Radiology Review Manual (Dahnert, Radiology Review Manual)

Authors: Dahnert, Wolfgang

Title: Radiology Review Manual, 6th Edition

Copyright 2007 Lippincott Williams & Wilkins

> Table of Contents > Musculoskeletal System

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Musculoskeletal System

Differential Diagnosis of Musculoskeletal Disorders

Differential-Diagnostic Gamut of Bone Disorders

Conditions to be considered = dissect bone disease with a DIATTOM

DYSPLASIA = disturbance of bone growth
DYSTROPHY = disturbance of nutrition

Limping child

1 4 Years

4 10 Years

10 15 Years

Delayed bone age

Bone sclerosis

Diffuse Osteosclerosis

mnemonic: 5 M'S To PROoF

Constitutional Sclerosing Bone Disease

Sclerosing Bone Dysplasia

Solitary Osteosclerotic Lesion

Cortical Sclerotic Lesion in Child

Multiple Osteosclerotic Lesions

Bone-within-bone Appearance

= endosteal new bone formation

P.3

mnemonic: BLT PLT RSD RSD

Dense Metaphyseal Bands

mnemonic: DENSE LINES

Osteopenia

= decrease in bone quantity maintaining normal quality

Categories:

Osteoporosis

= reduced bone mass of normal composition secondary to

Incidence: 7% of all women aged 35 40 years; 1 in 3 women > age 65 years

Etiology:

Technique:

Osteoporosis of Spine

Osteomalacia

= accumulation of excessive amounts of uncalcified osteoid with bone softening + insufficient mineralization of osteoid due to

Etiology:

Histo: excess of osteoid seams + decreased appositional rate

P.5

Localized / Regional Osteopenia

Bone Marrow Edema

= hypointense on T1WI + hyperintense on T2WI relative to fatty marrow

Transverse Lucent Metaphyseal Lines

mnemonic: LINING

Frayed Metaphyses

mnemonic: CHARMS

Bone tumor

Role of Radiologist

Assessment of Aggressiveness

Local staging with MR imaging:

Local assessment with CT imaging:

Tumorlike Conditions

Pseudomalignant Appearance

Pattern of Bone Destruction

Size, Shape, and Margin of Bone Lesion

Tumor Position in Transverse Plane

Tumor Position in Longitudinal Plane

Tumors Localizing to Hematopoietic Marrow

Diffuse Bone Marrow Abnormalities in Childhood

Age Incidence of Malignant Bone Tumors

P.7

Sarcomas by Age

mnemonic: Every Other Runner Feels Crampy Pain On Moving
Ewing sarcoma 0 10 years
Osteogenic sarcoma 10 30 years
Reticulum cell sarcoma 20 40 years
Fibrosarcoma 20 40 years
Chondrosarcoma 40 50 years
Parosteal sarcoma 40 50 years
Osteosarcoma 60 70 years
Metastases 60 70 years

Age Incidence of Malignant Bone Tumors

Age [years] Tumor
0.1 Neuroblastoma
0.1 10 Ewing tumor in tubular bones (diaphysis)
10 30 Osteosarcoma (metaphysis); Ewing tumor in flat bones
30 40 Reticulum cell sarcoma (similar histology to Ewing tumor); fibrosarcoma; malignant giant cell tumor (similar histology to fibrosarcoma); parosteal sarcoma; lymphoma
>40 Metastatic carcinoma; multiple myeloma; chondrosarcoma

Round Cell Tumors

mnemonic: LEMON

Malignancy with Soft-tissue Involvement

mnemonic: My Mother Eats Chocolate Fudge Often

Tumor Matrix of Bone Tumors

Cartilage-forming Bone Tumors

Bone-forming Tumors

Fibrous Connective Tissue Tumors

Tumors of Histiocytic Origin

Tumors of Fatty Tissue Origin

Tumors of Vascular Origin

<1% of all bone tumors

Metastatic sites: lung, brain, lymph nodes, other bones

Tumors of Neural Origin

Intraosseous lesion

Bubbly Bone Lesion

mnemonic: FOGMACHINES

Infectious Bubbly Lesion

Blowout Lesion

Nonexpansile Unilocular Well-demarcated Bone Defect

Nonexpansile Multilocular Well-demarcated Bone Defect

Expansile Unilocular Well-demarcated Osteolysis

Poorly Demarcated Osteolytic Lesion without Periosteal Reaction

Poorly Demarcated Osteolytic Lesion with Periosteal Reaction

Mixed Sclerotic and Lytic Lesion

Mixed Bone Lesion with Button Sequestrum

Mixed Bone Lesion without Sequestrum

Trabeculated Bone Lesion

1. Giant cell tumor: delicate thin trabeculae
2. Chondromyxoid fibroma: coarse thick trabeculae
3. Nonossifying fibroma: lobulated
4. Aneurysmal bone cyst: delicate, horizontally oriented trabeculae
5. Hemangioma: striated radiating trabeculae

Lytic Bone Lesion Surrounded by Marked Sclerosis

mnemonic: BOOST

Multiple Lytic Lesions

mnemonic: FEEHMI

Multiple Lytic Lesions in Child

Lytic Bone Lesion in Patient <30 Years of Age

mnemonic: CAINES

Lytic Bone Lesion on Both Sides of Joint

mnemonic: SAC

Multiple Bone Lesions & Soft-tissue Tumor

Osteoblastic Bone Lesion

Widespread Osteosclerotic Lesions

Dwarfism

Classification:

Terminology:

Micromelia = shortening involves entire limb (eg, humerus, radius + ulna, hand)
Rhizomelia = shortening involves proximal segment (eg, humerus)
Mesomelia = shortening involves intermediate segment (eg, radius + ulna)
Acromelia = shortening involves distal segment (eg, hand)

Micromelic Dwarfism

= disproportionate shortening of entire leg

Acromelic Dwarfism

= distal shortening (hands, feet)

Rhizomelic Dwarfism

= shortening of proximal segments (humerus, femur)

mnemonic: MA CAT

Osteochondrodysplasia

Lethal Bone Dysplasia

in order of frequency:

Nonlethal Dwarfism

Late-onset Dwarfism

Hypomineralization in Fetus

Large Head in Fetus

Narrow Chest in Fetus

Platyspondyly

Bowed Long Bones in Fetus

Bone Fractures in Fetus

Limb reduction anomalies

Amelia = absence of limb
Hemimelia = absence of distal parts
Phocomelia = proximal reduction with distal parts attached to trunk

Aplasia / Hypoplasia of Radius

mnemonic: The Furry Cat Hit My Dog

Pubic Bone Maldevelopment

mnemonic: CHIEF

Bone overgrowth

Bone Overdevelopment

Erlenmeyer Flask Deformity

= expansion of distal end of long bones, usually femur

mnemonic: TOP DOG

P.12

Periosteal reaction / periostitis

1. Trauma, hemophilia  
2. Infection  
3. Inflammatory: arthritis
4. Neoplasm  
5. Congenital: physiologic in newborn
6. Metabolic: hypertrophic osteoarthropathy, thyroid acropachy, hypervitaminosis A
7. Vascular: venous stasis

Solid Periosteal Reaction

Patterns:

Interrupted Periosteal Reaction

= pleomorphic, rapidly progressing process undergoing constant change

Symmetric Periosteal Reaction in Adulthood

Periosteal Reaction in Childhood

mnemonic: PERIOSTEAL SOCKS

Periosteal Reaction in Infant

DDx: motion artifact

Enthesopathy

Cause:

Location: at site of tendon + ligament attachment

Bone trauma

Childhood Fractures

Pseudarthrosis in Long Bones

Exuberant Callus Formation

Epiphysis

Premature Epiphyseal Ossification

Epiphyseal / Apophyseal Lesion

Subarticular Lesion

Stippled Epiphyses

Physeal / Metaphyseal Widening & Irregularity

Epiphyseal Overgrowth

Epiphyseolysis

= SLIPPED EPIPHYSIS(zone of maturing hypertrophic cartilage affected, not zone of proliferation)

Joints

Approach to Arthritis

mnemonic: ABCDE'S

Signs of Arthritis

Prevalence of arthritis: 15% of population in USA

Conventional x-ray:

NUC:

MR:

P.14

Classification of Arthritides

Spondyloarthritis and Positive HLA-B 27 Histocompatibility Complex

1. Ankylosing spondylitis 95%
2. Reiter disease 80%
3. Arthropathy of inflammatory bowel disease 75%
4. Psoriatic spondylitis 70%
5. Normal population 10%

Monoarthritis

Destructive Monoarthritis

Nonseptic Monoarthritis

Arthritis without Demineralization

mnemonic: PONGS

Arthritis with Demineralization

mnemonic: HORSE

Deforming Nonerosive Arthropathy

Arthritis with Periostitis

Premature Osteoarthritis

mnemonic: COME CHAT

Synovial Disease with Decreased Signal Intensity

= hemosiderin deposition

P.15

Chondrocalcinosis

mnemonic: WHIP A DOG
mnemonic: 3 C's
Crystals CPPD, sodium urate (gout)
Cations calcium (any cause of hypercalcemia), copper, iron
Cartilage degeneration osteoarthritis, acromegaly, ochronosis

Subchondral Cyst

Loose Intraarticular Bodies

Intraarticular Process with Cortical Erosion

Erosions of DIP Joints

Articular Disorders of Hand and Wrist

Arthritis Involving Distal Interphalangeal Joints

mnemonic: POEM

Ankylosis of Interphalangeal Joints

mnemonic: S - Lesions

Sacroiliitis

Joint anatomy:

Sacroiliac Joint Widening

mnemonic: CRAP TRAP

Sacroiliac Joint Fusion

mnemonic: CARPI

Widened Symphysis Pubis

mnemonic: EPOCH

Arthritis of Interphalangeal Joint of Great Toe

Ribs

Thoracic Deformity

Funnel Chest = Pectus Excavatum

May be associated with:

Barrel Chest

Congenital Rib Anomalies

Prevalence: 1.4%

Short Ribs

Rib Lesions

Expansile Rib Lesion

mnemonic: O FEEL THE CLAMP

Abnormal Rib Shape

Rib Notching on Inferior Margin

Unilateral Rib Notching on Inferior Margin

Rib Notching on Superior Margin

Dysplastic Twisted Ribbon Ribs

Bulbous Enlargement of Costochondral Junction

Wide Ribs

Slender Ribs

Dense Ribs

Hyperlucent Ribs

Congenitally Lucent Ribs

Acquired Lucent Ribs

Clavicle

Absence of Outer End of Clavicle

Penciled Distal End of Clavicle

mnemonic: SHIRT Pocket

Destruction of Medial End of Clavicle

mnemonic: MILERS

Wrist & hand

Carpal Angle

= angle of 130 formed by tangents to proximal row of carpal bones

P.20

Metacarpal Sign

Lucent Lesion in Finger

mnemonic: GAMES PAGES

Dactylitis

= expansion of bone with cystic changes

Resorption of Terminal Tufts

Acroosteolysis

Acquired Acroosteolysis

mnemonic: PETER's DIAPER SPLASH

P.21

Acroosteosclerosis

= focal opaque areas + endosteal thickening

Fingertip Calcifications

Brachydactyly

= shortening / broadening of metacarpals phalanges

Clinodactyly

= curvature of finger in mediolateral plane

Polydactyly

Syndactyly

= osseous cutaneous fusion of digits

Shoulder

Shoulder Instability

= recurrent subluxation / dislocation of humeral head out of the glenoid socket during activities causing symptoms

Stabilizer: inferior glenohumeral ligament-labrum complex (most important); anterior labrum-ligament complex

Lesions after first anterior dislocation:

Hip

Snapping Hip Syndrome

Increase in Teardrop Width

Protrusio Acetabuli

P.22

mnemonic: PROT

Pain with Hip Prosthesis

Approximately 120,000 hip arthroplasties per year in USA

Plain film:

NUC (83% sensitive, 88% specific):

Bone Scintigraphy:

Sequential bone-gallium scintigraphy:

Combined labeled leukocyte marrow scintigraphy:

Accuracy: >90%
Concept: Tc-99m sulfur colloid maps aberrantly located normal bone marrow as a point of reference for leukocyte tracer

Arthrography:

Aspiration of fluid under fluoroscopy (12 93% sensitive, 83 92% specific for infection):

Evaluation of total hip arthroplasty

MEASUREMENTS

Reference line: transischial tuberosity line (R)

Radiographic Findings in Total Hip Arthroplasty

Knee

Bone Contusion Pattern

Double PCL sign on MRI

Absent bow-tie sign

Unique Tibial Lesions

Tibiotalar Slanting

= downward slanting of medial tibial plafond

Foot

Abnormal Foot Positions

Clubfoot = Talipes Equinovarus

Common severe congenital deformity characterized by

Rocker-bottom Foot = Vertical Talus

Associated with: Arthrogryposis multiplex congenita; spina bifida; trisomy 13 18

Talar Beak = Hypertrophied Talar Ridge

Heel Pad Thickening

= heel pad thickening >25 mm (normal <21 mm)

mnemonic: MAD COP

P.25

Soft-tissue Masses of Foot + Ankle

Soft tissues

Categories of Soft-tissue Masses

Value of Conventional Radiographs

Histologic Classification of Soft-tissue Lesions

Fat-containing Soft-tissue Masses

P.26

Extraskeletal Osseous + Cartilaginous Tumors

DDx:

Soft-tissue Calcification

Metastatic / Metabolic Calcification

= deposit of calcium salts in previously normal tissue

Location: lung (alveolar septa, bronchial wall, vessel wall), kidney, gastric mucosa, heart, peripheral vessels

Cause:

Dystrophic Calcification

= in presence of normal serum Ca + P levels secondary to local electrolyte / enzyme alterations in areas of tissue injury / inflammation

Cause:

Generalized Calcinosis

Idiopathic Calcification

Interstitial Calcinosis

Calcinosis Circumscripta

Calcinosis Universalis

Soft-tissue Ossification

= formation of trabecular bone

Connective Tissue Disease

Types and most distinctive features:

Mixed Connective Tissue Disease

Muscle

MR signal intensity of normal muscle:

Intramuscular Mass

P.28

Muscle Edema

muscle hyperintensity on STIR images

Fatty Infiltration of Muscle

Fixation devices

Internal Fixation Devices

External Fixation Devices

= smooth / threaded pins / wires attached to an external frame

Intramedullary Fixation Devices

Use: diaphyseal long bone fractures

P.31

Anatomy and Metabolism of Bone

Bone minerals

Calcium

Absorption: facilitated by vitamin D
Excretion: related to dietary intake; >500 mg/24 hours = hypercalciuria

Phosphorus

Absorption: requires sodium; decreased by aluminum hydroxide gel in gut
Excretion: increased by estrogen, parathormone decreased by vitamin D, growth hormone, glucocorticoids

Bone marrow

Anatomic sites for MRI marrow screening:

Hormones

Parathormone

Major stimulus: low levels of serum calcium ions (action requires vitamin D presence)

Target organs:

(a) BONE: increase in osteocytic + osteoclastic activity mobilizes calcium + phosphate = bone resorption
(b) KIDNEY: (1) increase in tubular reabsorption of Ca2+

(2) decrease in tubular reabsorption of phosphate (+ amino acids) = phosphate diuresis
(c) GUT: increased absorption of calcium + phosphorus

Major function:

Vitamin D Metabolism

required for

Biochemistry:

Action:

(a) BOWEL: (1) increased absorption of calcium from bowel

(2) increased absorption of phosphate from distal small bowel
(b) BONE: (1) proper mineralization of osteoid

(2) mobilization of calcium + phosphate (potentiates parathormone action)
(c) KIDNEY: (1) increased absorption of calcium from renal tubule

(2) increased absorption of phosphate from renal tubule
(d) CELL: binds to receptor on nucleus which leads to activation of genes involved in calcium homeostasis

Calcitonin

secreted by parafollicular cells of thyroid

Major stimulus: increase in serum calcium

Target organs:

(a) BONE: (1) inhibits parathormone-induced osteoclasis by reducing number of osteoclasts

(2) enhances deposition of calcium phosphate; responsible for sclerosis in renal osteodystrophy
(b) KIDNEY: inhibits phosphate reabsorption in renal tubule
(c) GUT: increases excretion of sodium + water into gut
Major function: decreases serum calcium + phosphate

Physis = Growth Plate

Four distinct zones of cartilage in longitudinal layers

Normal shoulder joint anatomy

Glenoid Labrum

Superior Sublabral Sulcus / Recess

= variations in depth of sulcus between glenoid rim + labrum

Types of Attachment of the Biceps-Labral Complex

Location: 12 o'clock position at the site of biceps tendon attachment (in sagittal plane)

Types of attachment of biceps-labral complex (BLC):

Biceps Tendon

Glenohumeral Ligaments

= thickened bands of joint capsule functioning as shoulder stabilizers

Superior Glenohumeral Ligament

Middle Glenohumeral Ligament (MGL)

P.33

Inferior Glenohumeral Ligament (IGL)

Parts:

Normal Anatomic Variants of Shoulder

Sublabral Foramen = Sublabral Hole

= sublabral hole between labrum + glenoid

Incidence: 11% of individuals
Location: 2 o'clock position anterior to biceps tendon attachment

may coexist with sublabral recess

DDx: labral tear

Buford Complex

P.34

Foramen of Weitbrecht

= opening between SGL and MGL

Foramen of Rouviere

= opening between MGL and IGL

Rotator cuff muscles

mnemonic: SITS

Occurrence of bone centers at elbow

mnemonic: CRITOE
Capitellum 1 year (3 6 months)
Radial head 4 years (3 6 years)
Internal humeral epicondyle 7 years (5 7 years, last to fuse)
Trochlea 10 years (9 10 years)
Olecranon 10 years (6 10 years)
External humeral epicondyle 11 years (9 13 years)
mnemonic: Nelson's X: 1, 7, 10, 11 years

Carpal bones

mnemonic: Some Lovers Try Positions That They Can't Handle
proximal row distal row
Scaphoid Trapezium
Lunate Trapezoid
Triquetrum Capitate
Pisiform Hamate

Ulnar Variance

Definition:

Effect of wrist position:

Radiographic standard view of unloaded wrist:

Lower extremity

Pes Anserinus

Iliotibial Tract

= strong stabilizing band of deep fascia composed of the fusion of aponeurotic coverings of:

Insertion:

Hamstrings

Cruciate Ligaments

Both cruciate ligaments are intracapsular but extrasynovial!

Anterior Cruciate Ligament (ACL)

Function: limits anterior tibial translation
Origin: inner face of lateral femoral condyle
Insertion: noncartilaginous region of anterior aspect of intercondylar eminence of tibia
Anatomy: several distinct bundles of fibers

(1) large posterior bulk = spiraling together at femoral origin

(2) small anteromedial bundle diverging at tibial insertion

Posterior Cruciate Ligament (PCL)

Function: limits posterior tibial translation
Origin: in a depression posterior to intercondylar region of tibia below joint surface
Insertion: most distal + anterior aspect of inner face of medial femoral condyle

Collateral Ligaments of Knee Joint

Medial (Tibial) Collateral Ligament

Origin: just distal to adductor tubercle of femur
Insertion: anteromedial face of tibia distal to level of tibial tubercle about 5 cm below joint line

P.36

Muscle Attachments of Shoulder

Name of Muscle Origin Insertion
Deltoid lateral third of clavicle deltoid tuberosity of humerus
  lateral border of acromion deltoid tuberosity of humerus
  lower part of spinous process of scapula deltoid tuberosity of humerus
Subscapularis medial 2/3 of costal surface of scapula superior aspect of lesser tubercle of humerus
Pectoralis major    
    clavicular portion medial half of clavicle crest of greater tubercle of humerus
    sternocostal portion manubrium + corpus of sternum crest of greater tubercle of humerus
    abdominal portion anterior sheath of rectus abdominis crest of greater tubercle of humerus
Pectoralis minor 2nd / 3rd 5th ribs superomedial aspect of coracoid process
Biceps brachii    
    long head supraglenoid tubercle of scapula tuberosity of radius
    short head tip of coracoid process tuberosity of radius
Coracobrachialis tip of coracoid process medial surface of middle third of humerus
Supraspinatus supraspinatus fossa of scapula greater tubercle of humerus, highest facet
Infraspinatus infraspinatus fossa of scapula greater tubercle of humerus, middle facet
Teres minor upper 2/3 of lateral border of scapula greater tubercle of humerus, lower facet
Teres major dorsum of inferior angle of scapula inferior crest of lesser tubercle of humerus

Hip Flexors

Muscle Attachments of Thigh

Name of Muscle Origin Insertion
Gracilis inferior pubic ramus pes anserinus
Semimembranosus ischial tuberosity medial tibial condyle
Semitendinosus ischial tuberosity pes anserinus
Biceps femoris    
    long head ischial tuberosity fibular head
    short head lateral linea aspera fibular head
Adductor    
    longus superior pubic ramus medial linea aspera
    magnus inferior pubic ramus medial linea aspera
Sartorius anterior superior iliac spine pes anserinus
Quadriceps    
    rectus anterior inferior iliac spine patellar tendon
    vastus lateralis greater trochanter patellar tendon
    vastus medialis medial intertrochanteric line patellar tendon
Iliopsoas    
    iliacus ilium lesser trochanter
    psoas lumbar spine lesser trochanter
Tensor fasciae latae anterior superior iliac spine anterolateral tibia

P.37

Cross Section through L4-5

Cross Section through S1-2

Cross Section through Acetabular Roof

Cross Section through L5-S1

Cross Section through S4

Cross Section through Greater Trochanter

P.38

Cross Section through Obturator Foramen

Cross Section through Mid Thigh

Fat Pads of the Right Hip in Perfect AP Position

Cross Section through Minor Trochanter

Cross Section through Mid Thigh

Bony Landmarks of the Right Hip in Perfect AP Position

P.39

deep and superficial dark bands separated by a thin bursa + fatty tissue (on coronal MR)

Lateral (Fibular) Collateral Ligament

Origin: lateral aspect of lateral femoral condyle
Insertion: styloid process of fibular head

Posterior Ankle Tendons

Achilles Tendon

Size: 7 mm in AP thickness (largest tendon of the body)
Origin: gastrocnemius + soleus muscle

Plantaris Tendon

parallels Achilles tendon anteromedially

Insertion: Achilles tendon. calcaneus, plantar fascia

Medial Flexor Tendons

Posterior Tibialis Tendon

Size: twice the size of flexor digitorum longus tendon
Course: beneath medial malleolus (used as pulley)
Insertion: navicular, all cuneiforms, base of first four metatarsals, os naviculare

Flexor Digitorum Longus

Flexor Hallucis Longus

Course: groove beneath posterior process of talus, beneath sustentaculum tali
Insertion: base of distal phalanx of hallux

Cross Section through Distal Right Leg mnemonic for medial tendons: Tom, Dick and Harry from medial to lateral

P.40

Plantar Compartments of the Midfoot

Plantar Compartments of the Forefoot

Medial compartment = bordered by medial septum (extending from plantar aponeurosis to navicular bone, medial cuneiform bone, and lateral border of plantar surface of 1st metatarsal bone); contains abductor hallucis m. + flexor hallucis brevis m. + flexor hallucis longus tendon
Lateral compartment = bordered by lateral septum (extending from plantar aponeurosis to medial surface of 5th metatarsal bone); contains abductor m. + short flexor m. + opponens m. of 5th toe
Central compartment = bordered by medial + lateral septa; communicates directly with posterior compartment of calf; subdivided by horizontal septa: adductor hallucis m. separated from quadratus plantae m.; contains flexor digitorum brevis m. + flexor digitorum longus tendon + quadratus plantae m. + lumbricales mm. + adductor hallucis m.
Deep subcompartment = bordered by transverse fascia of forefoot; separated from quadratus plantae m.; contains adductor hallucis m.

P.41

Accessory Ossicles of the Foot

Calcaneal Pitch = Calcaneal Inclination Angle = determines longitudinal arch of foot; angle between line drawn along the inferior border of calcaneus connecting the anterior and posterior prominences + line representing the horizontal surface

Boehler Angle = angle between first line drawn from posterosuperior prominence of calcaneus anteriorly to sustentaculum tali + second line drawn from anterosuperior prominence posteriorly to sustentaculum tali; measures integrity of calcaneus

Talocalcaneal Angle on LAT View = angle between lines drawn through mid-transverse planes of talus + calcaneus; the midtalar line parallels the longitudinal axis of the first metatarsal

Intermetatarsal Angle = amount that 1st + 2nd metatarsals diverge from each other

Heel Valgus cannot be measured directly on radiographs but inferred from the talocalcaneal angle and estimated on coronal CT sections

Talocalcaneal Angle on AP View = KITE ANGLE = the midtalar and midcalcaneal lines parallel the 1st + 4th metatarsals; angle is greater in infants

Angle of Metatarsal Heads = obtuse angle formed by lines tangential to metatarsal heads

P.42

Bone and Soft-Tissue Disorders

Achondrogenesis

= autosomal recessive lethal chondrodystrophy characterized by extreme micromelia, short trunk, large cranium

TRIAD: (1) severe short-limb dwarfism

(2) lack of vertebral calcification

(3) large head with normal / decreased calvarial ossification
Birth prevalence: 2.3:100,000
Path: disorganization of cartilage
Prognosis: lethal often in utero / within few hours or days after birth (respiratory failure)
DDx: often confused with thanatophoric dwarfism

Achondroplasia

Heterozygous Achondroplasia

Incidence: 1:26,000 66,000 births, most common of lethal bone dysplasias; M < F
Cx: apnea + sudden death (due to compression of spinal cord + lower brain stem)

OB-US (diagnosable >21 27th week GA):

P.43

Cx: (1) Hydrocephalus + syringomyelia (small foramen magnum)

(2) Recurrent ear infection (poorly developed facial bones)

(3) Neurologic complications (compression of spinal cord, lower brainstem, cauda equina, nerve roots): apnea and sudden death

4) Crowded dentition + malocclusion
Prognosis: long life
DDx: various mucopolysaccharidoses

Homozygous Achondroplasia

= hereditary autosomal dominant disease with severe features of achondroplasia (disproportionate limb shortening, more marked proximally than distally)

Risk: marriage of two achondroplasts to each other
Prognosis: often stillborn; lethal in neonatal period (from respiratory failure)
DDx: thanatophoric dysplasia

Pseudoachondroplasia

= part of osteochondroplasias

Prevalence: 4:1,000,000
Etiology: mutation of genes encoding for cartilage oligomeric matrix protein (COMP) on chromosome 19 (closely related to multiple epiphyseal dysplasia)
Age at presentation: 2 4 years
Cx: premature osteoarthritis
DDx: (1) Achondroplasia (large head with prominent frontal region + depressed bridge of nose, normal epiphyses, trident hands)

(2) Multiple epiphyseal dysplasia (near normal pelvis)

(3) Spondyloepiphyseal dysplasia congenita (hip joints more affected + near normal extremities)

(4) Diastrophic dwarfism (joint contractures and scoliosis at birth / in early infancy)

(5) Metatrophic dwarfism (dumbbell-shaped long bones + flattened vertebrae in infancy, less epiphyseal involvement)

Acrocephalosyndactyly

= syndrome characterized by

Type I : Apert syndrome = acrocephalosyndactyly
Type II : Vogt cephalosyndactyly
Type III : Acrocephalosyndactyly with asymmetry of skull + mild syndactyly
Type IV : Wardenburg type
Type V : Pfeiffer type

Acroosteolysis, Familial

dominant inheritance

Age: onset in 2nd decade; M:F = 3:1

Acromegaly

Etiology: excess growth hormone due to eosinophilic adenoma / hyperplasia in anterior pituitary

Actinomycosis

= chronic suppurative infection characterized by formation of multiple abscesses, draining sinuses, abundant granulation tissue secondary to mucosal disruption + low tissue oxygen tension

Organism: Actinomyces israelii / naeslundii / viscosus / eriksonii, gram-positive non acid-fast anaerobic pleomorphic small filamentous bacterium with proteolytic activity, superficially resembling the morphology of a hyphal fungus (Gomori methenamine silver stain-positive filaments); closely related to mycobacteria

Spread:

Histo: mycelial form in tissue; as opportunistic pathogens rod-shaped bacterial form normally inhabits oropharynx (dental caries, gingival margins, tonsillar crypts) + GI tract
Predisposed: individuals with very poor dental hygiene, immunosuppressed patients
Location: mandibulofacial > intestinal > lung

Clinical types:

Dx: anaerobic culture; species-specific antibodies
Rx: surgical d bridement + high doses of penicillin

Adamantinoma

Ainhum Disease

Rx: early surgical resection of groove with Z-plasty
DDx: (1) Neuropathic disorders (diabetes, leprosy, syphilis)

(2) Trauma (burns, frostbite)

(3) Acroosteolysis from inflammatory arthritis, infection, polyvinyl chloride exposure

(4) Congenitally constricting bands in amniotic band syndrome

Amyloidosis

= extracellular deposition of a chemically diverse group of protein polysaccharides in body tissues ( 2-microglobulin); tends to form around capillaries + endothelial cells of larger blood vessels causing ultimately vascular obliteration with infarction

2-microglobulin = low-molecular-weight serum protein not filtered by standard dialysis membranes

Path: stains with Congo red
At risk: patients on long-term hemodialysis

Amyloid Arthropathy

= synovial-articular pattern of amyloidosis

Location: cervical spine, hip, shoulder, elbow
DDx: inflammatory arthritis

Diffuse Amyloid Marrow Deposition

Amyloidoma

Aneurysmal Bone Cyst

= expansile pathologically benign lytic lesion of bone containing thin-walled cystic cavities filled with chronic blood products; name derived from roentgen appearance

Etiology:

Histo: intraosseous arteriovenous malformation with honeycombed spaces filled with blood + lined by granulation tissue / osteoid; areas of free hemorrhage; sometimes multinucleated giant cells; solid component predominates in 5 7%

Types:

Age: peak age 16 years (range 10 30 years); in 75% <20 years; F > M
Location: (a) spine (12 30%) with slight predilection for posterior elements; thoracic > lumbar > cervical spine (22%); involvement of vertebral body (40 90%); may involve two contiguous vertebrae (25%)

(b) long bones: eccentric in metaphysis of femur, tibia, humerus, fibula; pelvis

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CT:

MR:

NUC:

Angio:

Prognosis: 20 30% recurrence rate
Rx: preoperative embolotherapy; complete resection; radiation therapy (subsequent sarcoma possible)
Cx: (1) pathologic fracture (frequent)

(2) extradural block with paraplegia
DDx: (1) Giant cell tumor (particularly in spine)

(2) Hemorrhagic cyst (end of bone / epiphysis, not expansile)

(3) Enchondroma

(4) Metastasis (renal cell + thyroid carcinoma)

(5) Plasmacytoma

(6) Chondro- and fibrosarcoma

(7) Fibrous dysplasia

(8) Hemophilic pseudotumor

(9) Hydatid cyst

Angiomatosis

= diffuse infiltration of bone / soft tissue by hemangiomatous / lymphangiomatous lesions

Age: first 3 decades of life

May be associated with:

Angiosarcoma

= aggressive vascular malignancy with frequent local recurrence + distant metastasis

Histo: vascular channels surrounded by hemangiomatous / lymphomatous cellular elements with high degree of anaplasia
Age: M:F = 2:1
Associated with: Stewart-Treves syndrome

= angiosarcoma with chronic lymphedema developing in postmastectomy patients

Location: skin (33%); soft tissue (24%); bone (6%): tibia (23%), femur (18%), humerus (13%), pelvis (7%)
DDx: hemangioendothelioma, hemangiopericytoma

Ankylosing Spondylitis

= autoimmune disease of unknown etiology primarily affecting axial skeleton

Age: 15 35 years; M:F = 3:1 10:1; Caucasians:Blacks = 3:1
Associated with: (1) ulcerative colitis, regional enteritis

(2) iritis in 25%

(3) aortic insufficiency + atrioventricular conduction defect

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Anterior Tibial Bowing

Apert Syndrome

= ACROCEPHALOSYNDACTYLY type I

Frequency: 5.5:1,000,000 neonates
Etiology: autosomal dominant with incomplete penetrance; sporadic (in majority)

Associated with CNS anomalies:

Arteriovenous Fistula of Bone

Etiology: (a) acquired (usually gunshot wound)

(b) congenital
Location: lower extremity most frequent

Arthrogryposis

Pathophysiology: congenital / acquired defect of motor unit (anterior horn cells, nerve roots, peripheral nerves, motor end plates, muscle) early in fetal life with immobilization of joints at various stages in their development
Cause: ? neurotropic agents, toxic chemicals, hard drugs, hyperthermia, neuromuscular blocking agents, mytotic abnormalities, mechanical immobilization
Incidence: 0.03% of newborn infants; 5% risk of recurrence in sibling
Path: diminution in size of muscle fibers + fat deposits in fibrous tissue
Associated with: (1) neurogenic disorders (90%)

(2) myopathic disorders

(3) skeletal dysplasias

(4) intrauterine limitation of movement (myomata, amniotic band, twin, oligohydramnios)

(5) connective tissue disorders
Distribution: all extremities (46%), lower extremities only (43%), upper extremities only (11%); peripheral joints >> proximal joints; symmetrical

Asphyxiating Thoracic Dysplasia

Avascular Necrosis

Terminology (now often used interchangeably):

Histo:

Pathogenesis:

Cause:

mnemonic: PLASTIC RAGS
mnemonic: GIVE INFARCTS
Location: femoral head (most common), humeral head, femoral condyles

Radiography:

Avascular Necrosis of Hip

Plain film (positive only several months after symptoms):

Classification (Steinberg):

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P.50

Stage 0 = normal
Stage I = normal / barely detectable trabecular mottling; abnormal bone scan / MRI
Stage IIA = focal sclerosis + osteopenia
Stage IIB = distinct sclerosis + osteoporosis + early crescent sign
Stage IIIA = subchondral undermining ( crescent sign ) + cyst formation
Stage IIIB = mild alteration in femoral head contour / subchondral fracture + normal joint space
Stage IV = marked collapse of femoral head + significant acetabular involvement
Stage V = joint space narrowing + acetabular degenerative changes

NUC (80 85% sensitivity):

Technique: imaging improved with double counts, pinhole collimation

CT (utilized for staging of known disease):

MR (90 100% sensitive, 85% specific for symptomatic disease):

Prevalence of clinically occult disease: 6%

Blount Disease

Calv -K mmel-Verneuil Disease

Freiberg Disease

[Albert Henry Freiberg (1868 1940), orthopedic surgeon in Cincinnati, Ohio]

= osteochondrosis of head of 2nd (3rd / 4th) metatarsal

Age: 10 18 years; M:F = 1:3

Early:

Late:

Kienb ck Disease

K hler Disease

Legg-Calv -Perthes Disease

Panner Disease

Preiser Disease

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Spontaneous Osteonecrosis of Knee

= SONK

Cause: ? meniscal tear (78%), trauma with resultant microfractures, vascular insufficiency, degenerative joint disease, severe chondromalacia, gout, rheumatoid arthritis, joint bodies, intraarticular steroid injection (45 85%)
Age: 7th decade (range 13 83 years)
Location: weight-bearing medial condyle more toward epicondylus (95%), lateral condyle (5%), may involve tibial plateau

Talar AVN

Basal Cell Nevus Syndrome

Association: high incidence of medulloblastoma in children; ovarian fibroma (in 17%); cardiac fibroma (in 14%)

Battered Child Syndrome

Cx: (1) Brain atrophy (up to 100%)

(2) Infarction (50%)

(3) Subdural hygroma

(4) Encephalomalacia

(5) Porencephaly
DDx: normal periostitis of infancy, long-term ventilator therapy in prematurity, osteogenesis imperfecta, congenital insensitivity to pain, infantile cortical hyperostosis, Menkes kinky hair syndrome, Schmid-type chondrometaphyseal dysplasia, scurvy, congenital syphilitic metaphysitis

Benign Cortical Defect

= developmental intracortical bone defect

Age: usually 1st 2nd decade; uncommon in boys <2 years of age; uncommon in girls <4 years of age
Cx: pathologic / avulsion fracture following minor trauma (infrequent)
Prognosis: (1) Spontaneous healing resulting in sclerosis / disappearance

(2) Ballooning of endosteal surface of cortex = fibrous cortical defect

(3) Medullary extension resulting in nonossifying fibroma

Bone Infarct

Etiology:

Medullary Infarction

Location: distal femur, proximal tibia, iliac wings, ribs, humeri

Cortical Infarction

Cx: (1) Growth disturbances

    cupped / triangular / coned epiphyses

    H-shaped vertebral bodies

(2) Fibrosarcoma (most common), malignant fibrous histiocytoma, benign cysts

(3) Osteoarthritis

Bone Island

Age: any age (mostly 20 80 years of age); grows more rapidly in children
Histo: nest of lamellar compacted bone with haversian system embedded within medullary canal
Pathogenesis: ? misplaced cortical hamartoma,? developmental error of endochondral ossification as a coalescence of mature bone trabeculae with failure to undergo remodeling; not inherited
asymptomatic  
Location: ilium + proximal femur (88 92%), ribs, spine (1 14%), humerus, phalanges (not in skull)
Prognosis: may increase to 8 12 cm over years (40%); may decrease / disappear
DDx: (1) Osteoblastic metastasis (aggressive, break through cortex, periosteal reaction)

(2) Low-grade osteosarcoma (cortical thickening, extension beyond medullary cavity)

(3) Osteoid osteoma (pain relieved by aspirin, nidus)

(4) Benign osteoblastoma

(5) Involuted nonossifying fibroma replaced by dense bone scar

(6) Eccentric focus of monostotic fibrous dysplasia

(7) Osteoma (surface lesion)

Brucellosis

= multisystemic zoonosis of worldwide distribution; endemic in Saudi Arabia, Arabian Peninsula, South America, Spain, Italy (secondary to ingestion of raw milk / milk products)

Organism: small gram-negative nonmotile, nonsporing, aflagellate, nonencapsulated coccobacilli: Brucella abortus, B. suis, B. canis, B. melitensis
Histo: small intracellular pathogens shed in excreta of infected animals (urine, stool, milk, products of conception) cause small noncaseating granuloma within RES
Location: commonest site of involvement is reticulo-endothelial system; musculoskeletal system
Dx: serologic tests (enzyme-linked immunosorbent assay, counterimmunoelectrophoresis, rose bengal plate test
Rx: combination of aminoglycosides + tetracyclines
DDx: fibrous dysplasia, benign tumor, osteoid osteoma

Caisson Disease

= DECOMPRESSION SICKNESS = THE BENDS

Etiology: during too rapid decompression = reduction of surrounding pressure (ascent from dive, exit from caisson / hyperbaric chamber, ascent to altitude) nitrogen bubbles form (nitrogen more soluble in fat of panniculus adiposus, spinal cord, brain, bones containing fatty marrow)

Calcium Pyrophosphate Dihydrate Crystal Deposition Disease

Camptomelic Dysplasia

= sporadic / autosomal recessive dwarfism

Incidence: 0.05:10,000 births

Associated with:

Prognosis: death usually <5 months of age (within first year in 97%) due to respiratory insufficiency

Carpal Tunnel Syndrome

= entrapment syndrome caused by chronic pressure on the median nerve within the carpal tunnel

Cause: repetitive wrist / finger flexion; carpal tunnel crowding by cyst / mass / flexor tendon tendinitis or tenosynovitis / anomalous origin of lumbrical muscles
Pathogenesis: probably ischemia with venous congestion (stage 1), nerve edema from anoxic damage to capillary endothelium (stage 2), impairment of venous + arterial blood supply (stage 3)

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Carpenter Syndrome

Cerebrocostomandibular Syndrome

Chondroblastoma

= CODMAN TUMOR = BENIGN CHONDROBLASTOMA = CARTILAGE-CONTAINING GIANT CELL TUMOR

Incidence: 1% of primary bone neoplasms (700 cases in world literature)
Age: peak in 2nd decade (range of 8 59 years); 10 26 years (90%); M:F = 2:1; occurs before cessation of enchondral bone growth
Path: derived from primitive cartilage cells
Histo: polyhedral chondroblasts + multinucleated giant cells + nodules of pink amorphous material

(= chondroid) = epiphyseal chondromatous giant cell tumor (resembles chondromyxoid fibroma); chicken wire calcification = pericellular deposition of calcification is virtually PATHOGNOMONIC

Location:

Site: eccentric medullary, subarticular location with open growth plate (98% begin within epiphysis); tumor growth may continue to involve metaphysis (50%) + rarely diaphysis

MR:

Prognosis: almost always benign; may become locally aggressive; rarely metastasizes
Dx: surgical biopsy
Rx: curettage + bone chip grafting (recurrence in 25%)
DDx: (1) Ischemic necrosis of femoral head (may be indistinguishable, more irregular configuration)

(2) Giant cell tumor (usually larger + less well demarcated, not calcified, older age group with closed growth plate)

(3) Chondromyxoid fibroma

(4) Enchondroma

(5) Osteomyelitis (less well-defined, variable margins)

(6) Aneurysmal bone cyst

(7) Intraosseous ganglion

(8) Langerhans cell histiocytosis (less well-defined, variable margins)

(9) Primary bone sarcoma

Chondrodysplasia Punctata

Cx: respiratory failure (severe underdevelopment of ribs), tracheal stenosis, spinal cord compression
DDx: (1) Cretinism (may show epiphyseal fragmentation, much larger calcifications within epiphysis)

(2) Warfarin embryopathy

(3) Zellweger syndrome

Chondroectodermal Dysplasia

Chondromalacia Patellae

Chondromyxoid Fibroma

Rare benign cartilaginous tumor; initially arising in cortex

Incidence: <1% of all bone tumors
Histo: chondroid + fibrous + myxoid tissue (related to chondroblastoma); may be mistaken for chondrosarcoma
Age: peak 2nd 3rd decade (range of 5 79 years); M:F = 1:1

Chondrosarcoma

Spread: via marrow cavity / periosteum
Metastases (uncommon) to: lung, epidural space

CT:

MR:

Central Chondrosarcoma

Peripheral Chondrosarcoma

Clear Cell Chondrosarcoma

Histo: small lobules of tissue composed of cells with centrally filled vesicular nuclei surrounded by large clear cytoplasm
Age: 19 68 years, predominantly after epiphyseal fusion
Location: proximal femur, proximal humerus, proximal ulna, lamina vertebrae (5%); pubic ramus
Site: epiphysis

Enchondroma versus Chondrosarcoma in Appendicular Skeleton

  Enchondroma Intramedullary Chondrosarcoma
Mean age and sex 40 years; M:F = 2:3 50 years; M:F = 11:9
Palpable mass 28% 82%
Pain 40% (fracture associated) 95% (longer duration + increasing severity)
Lesion location hands, feet axial skeleton (spine, pelvis)
Site diaphysis metaphysis, epiphysis
Lesion size <5 cm >5 6 cm
Endosteal scalloping    
   relative to cortical thickness 90% <2/3 of cortical thickness 90% >2/3 of cortical thickness,
   relative to lesion length 66% along <2/3 of lesion 79% along >2/3 of lesion
Cortical remodeling (radiography) 15% 47%
Cortical thickening (radiography) 17% 47%
Periosteal reaction (radiography) 3% 47%
Pathologic fracture (radiography) 5% 27%
Matrix mineralization (CT) 100% (more extensive) 94% (less extensive)
Cortical destruction (CT) 8% 88%
Soft-tissue extension (MR) 3% 76%
Small hyperintense foci (T1WI) 65% 35%

Extraskeletal Chondrosarcoma

Incidence: 2% of all soft-tissue sarcomas

Myxoid Extraskeletal Chondrosarcoma

(most common)

Mean age: 50 years (range 4 92 years); M > F
Histo: surrounded by fibrous capsule + divided into multiple lobules by fibrous septa; delicate strands of small elongated chondroblasts are suspended in an abundant myxoid matrix; foci of mature hyaline cartilage are rare

MR:

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Prognosis: 45% 10-year survival rate; 5 15 years survival after development of metastases

Extraskeletal Mesenchymal Chondrosarcoma

MR:

Prognosis: 25% 10-year survival rate

Cleidocranial Dysostosis

OB-US:

Coccidioidomycosis

Histo: chronic granulomatous process in bones, joints, periarticular structures
Location: (a) bones: most frequently in metaphyses of long bones + medial end of clavicle, spine, ribs, pelvis / bony prominences of patella, tibial tuberosity, calcaneus, olecranon, acromion

(b) weight-bearing joints (33%): ankle, knee, wrist, elbow

    desert rheumatism = immune-complex mediated arthritis

(c) tenosynovitis of hand, bursitis

Congenital Insensitivity to Pain With Anhydrosis

Cornelia De Lange Syndrome

Cortical Desmoid

Cri-Du-Chat Syndrome

Crouzon Syndrome

OB-US:

Cruciate Ligament Injury

Anterior Cruciate Ligament Injury (ACL tear)

Frequency: in up to 69% of all patients undergoing arthroscopy; in up to 72% of acutely injured knees with hemarthrosis
Mechanism: twisting, valgus impaction + internal rotation, hyperextension of knee with foot planted (football) / lower leg forcibly externally rotated during knee flexion (backwards fall while skiing)

Secondary signs (low sensitivity, high specificity):

Associated signs:

False-positive Dx:

Associated injuries:

Rx: (1) conservative: strengthening of quadriceps muscle + brace for activities

(2) arthroscopic reconstruction with autograft (patellar tendon / combined semitendinosus and gracilis tendon) or allograft (cadaveric patellar / Achilles tendon)

Subacute ACL Tear

Definition: few weeks after injury

Chronic ACL Tear

Definition: months to years after injury

Partial ACL Tear (15%)

Posterior Cruciate Ligament Injury (PCL)

Prevalence: 2 23% of all knee injuries

Mechanism:

Deep Fibromatosis

Aggressive Infantile Fibromatosis

Location: head, neck (tongue, mandible, mastoid), shoulder, thigh, foot

Extraabdominal Desmoid Tumor

Peak age: 25 35 years
Histo: parallel halo arrays of uniform-appearing fibroblasts surrounded by highly variable amounts of collagen fibers with infiltrative growth pattern

MR:

Cx: compresses / engulfs adjacent structures
Prognosis: 75% recurrence within 2 years after surgical excision (up to 87% local recurrence in <30 years of age; 20% recurrence rate in >20 years of age)

Abdominal Desmoid Tumor

Location: mesentery (most common mesenteric primary), musculoaponeurosis of rectus, internal oblique muscle; occasionally external oblique muscle
Age: peak age in 3rd decade, 70% between 20 and 40 years of age; M:F = 1:3
Path: poorly circumscribed coarsely trabeculated tumor resembling scar tissue, confined to musculature + overlying aponeurosis
Histo: elongated spindle-shaped cells of uniform appearance, septated by dense bands of collagen, infiltration of adjacent tissue (DDx: low-grade fibrosarcoma, reactive fibrosis)
Associated with: Gardner syndrome, multiple pregnancies, prior trauma

firm slowly growing deep-seated mass

Size: 5 20 cm in diameter

MR:

CT:

US:

Cx: compression / displacement of bowel / ureter, intestinal perforation
Prognosis: locally aggressive growth; 25 65% recurrence rate
Rx: local resection + radiotherapy, antiestrogen therapy
DDx: (1) Malignant tumor: metastasis, fibrosarcoma, rhabdomyosarcoma, synoviosarcoma, liposarcoma, fibrous histiocytoma, lymphoma

(2) Benign tumor: neurofibroma, neuroma, leiomyoma

(3) Acute hematoma

Infantile Myofibromatosis

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P.63

Cause: unknown
Frequency: most common fibromatosis in childhood
Age: at birth (in 60%), <2 years (in 89%); M:F = 1.7:1
Path: well-marginated soft-tissue lesion 0.5 3 cm in diameter with scarlike consistency infiltration of surrounding tissues
Histo: spindle-shaped cells in short bundles and fascicles in periphery of lesion with features of both smooth muscle + fibroblasts; hemangiopericytoma-like pattern in center with necrosis, hyalinization, calcification

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Dermatomyositis

= autoimmune inflammatory myopathy with diffuse nonsuppurative inflammation of striated muscle + skin

Cause: cell-mediated (type IV) autoimmune attack on striated muscle
Pathophysiology: damaged chondroitin sulfate no longer inhibits calcification
Path: atrophy of muscle bundles followed by edema and coagulation necrosis, fibrosis, calcification
Histo: mucoid degeneration with round cell infiltrates concentrated around blood vessels
Age: bimodal: 5 15 and 50 60 years; M:F = 1:2

Clinical forms:

Cx: increased prevalence of malignant neoplasms of breast, prostate, lung, ovary, GI tract, kidney
Dx: muscle biopsy (normal in up to 15%)

Polymyositis

Desmoplastic Fibroma

Incidence: 107 cases in world literature
Histo: intracellular collagenous material in fibroblasts with small nuclei
Age: mean of 21 years (range 15 months to 75 years); in 90% <30 years; M:F = 1:1
Location: mandible (26%), ilium (14%), >50% in long bones (femur [14%], humerus [11%], radius [9%], tibia [7%], clavicle), scapula, vertebra, calcaneus
Site: central meta- / diaphyseal (if growth plate open); may extend into epiphysis with subarticular location (if growth plate closed)
Cx: pathologic fracture (9%)
Prognosis: 52% rate of local recurrence
Rx: wide excision
DDx: (1) Giant cell tumor (round rather than oval, may extend into epiphysis + subchondral bone plate)

(2) Fibrous dysplasia (occupies longer bone, contains mineralized matrix, often with sclerotic rim)

(3) Aneurysmal bone cyst (eccentric blowout appearance rather than fusiform)

(4) Chondromyxoid fibroma (eccentric with delicate marginal sclerosis + scalloped border)

Developmental Dysplasia of Hip (DDH)

Etiology:

Incidence: 0.15% of neonates (Australia 1%, Netherlands 3.7%, Poland 3.9%, Israel 5.9%, Austria 6.6%, Norway 16.9%)
Age: most dislocations probably occur after birth; M:F = 1:4 1:8; Caucasians > Blacks

Increased risk:

P.66

Radiographic Lines of Hip Joint Position

Anatomy: acetabulum has a small bony component + a large cartilaginous component at birth; acetabulum highly susceptible for modeling within first 6 weeks of age + minimally susceptible >16 weeks of age

Classification:

Location: left:right:bilateral = 11:1:4

Radiologic lines:

AP pelvic radiograph: >6 8 weeks of age (von Rosen view = legs abducted 45 + thighs internally rotated)

US (practical only up to 4 6 months of age):

Prognosis: alpha-angle <50 at birth / 50 59 after 3 months indicates significant risk for dislocation without treatment; follow-up at 4-week intervals are recommended

No Caption Available.

P.68

CT:

Cx: (1) Avascular necrosis of femoral head

(2) Intraarticular obstacle to reduction

   (a) pulvinar = fibrofatty tissue at apex of acetabulum

   (b) hypertrophy of ligamentum teres

   (c) labral hypertrophy / inversion

(3) Extraarticular obstacle to reduction (iliopsoas tendon impingement on anterior joint capsule with infolding of joint capsule)
Prognosis: 78% of hips become spontaneously normal by 4th week + 90% by 9th week
Rx: (1) Flexion-abduction-external rotation brace (Pavlik harness) / splint / spica cast

(2) Femoral varus osteotomy

(3) Pelvic (Salter) / acetabular rotation

(4) Increase in acetabular depth (Pemberton)

(5) Medialization of femoral head (Chiari)

Diastrophic Dysplasia

Prognosis: death in infancy (due to abnormal softening of tracheal cartilage)

Diffuse Idiopathic Skeletal Hyperostosis

Etiology:

? hypertrophic variant of spondylosis deformans

Age: >50 years; M:F = 3:1
Cx: postoperative heterotopic bone formation (hip)
DDx: (1) Fluorosis (increased skeletal density)

(2) Acromegaly (posterior scalloping, skull features)

(3) Hypoparathyroidism

(4) X-linked hypophosphatemic vitamin D resistant rickets

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(5) Ankylosing spondylitis (squaring of vertebral bodies, coarser syndesmophytes, sacroiliitis, apophyseal alteration)

(6) Intervertebral osteochondrosis (vacuum phenomenon, vertebral body marginal sclerosis, decreased intervertebral disk height)

Dislocation

Hip Dislocation

Incidence: 5% of all dislocations

Patellar Dislocation

= TRANSIENT LATERAL PATELLAR DISLOCATION

Incidence: 2 3% of all knee injuries
Mechanism: during attempt to slow forward motion while pivoting medially on a planted foot; internal rotation of femur on fixed tibia while knee is flexed + quadriceps contraction produces a net lateral force
At risk: shallow trochlear groove
Associated with: medial meniscal tear / major ligamentous injury in 31%
Age: young physically active people

MR:

Rx: (1)Temporary immobilization + rehabilitation: successful in 75%

(2) Surgery: fixation of osteochondral fragments, medial capsule repair, lateral retinacular release, vastus medialis et lateralis rearrangement, medial retinaculum reefing

Shoulder Dislocation

Sternoclavicular Dislocation (3%)

Acromioclavicular Dislocation (12%)

Grade 1 = soft-tissue swelling + no joint widening
Grade 2 = subluxation with elevation of clavicle of <5 mm (weight-bearing!)
Grade 3 = dislocation with wide AC joint + increased coracoclavicular distance

Glenohumeral Dislocation (85%)

Anterior / Subcoracoid Shoulder Dislocation

(95% of all shoulder dislocations)

Types: subcoracoid, subglenoid, subclavicular, intrathoracic
Mechanism: external rotation + abduction (fall on outstretched arm / hand behind occiput); 40% recurrent
Age: in younger individuals in their teens

May be associated with:

P.70

MRI (arthrography improves sensitivity to 89 99%, and specificity to >90%):

Cx: (1) Recurrent dislocations (in up to 90% of young active individuals)

(2) Repeated dislocations due to incomplete / inadequate healing = chronic recurrent anterior shoulder instability

(3) Arthritis (with repeated subluxations)
Rx: (1) Conservative treatment for most

(2) Surgical fixation for young athletes

Posterior Shoulder Dislocation (2 4%)

Cause: (a)traumatic: convulsive disorders /electric shock therapy

(b) nontraumatic: voluntary, involuntary, congenital, developmental
Types: subacromial, subglenoid, subspinous

May be associated with:

MRI:

Inferior Shoulder Dislocation (1 2%)

Mechanism: severe hyperabduction of arm resulting in impingement of humeral head against acromion
Cx: rotator cuff tear; fracture of acromion inferior glenoid fossa greater tuberosity; neurovascular injury

No Caption Available.

Superior Shoulder Dislocation (<1%)

= humeral head driven upward through rotator cuff

May be associated with: fracture of humerus, clavicle, acromion
DDx: drooping shoulder (transient phenomenon after fracture of surgical neck of humerus due to hemarthrosis / muscle imbalance)

Gadolinium Shoulder Arthrography

Wrist Dislocation

Mechanism: fall on outstretched hand
Incidence: 10% of all carpal injuries

Lunate Dislocation

Perilunate Dislocation

Rotary Subluxation of Scaphoid

= tearing of interosseous ligaments of lunate, scaphoid, capitate

Mechanism: acute dorsiflexion of wrist; may be associated with rheumatoid arthritis

Midcarpal Dislocation

Down Syndrome

= MONGOLISM = TRISOMY 21

Chromosomes: 95% nondisjunction, 5% translocation
Incidence: 1:870 live births, most common karyotype / chromosomal abnormality in USA

P.71

P.72

Dyschondrosteosis

DDx: pseudo-Madelung deformity (from trauma / infection)

Dysplasia Epiphysealis Hemimelica

Incidence: 1:1,000,000
Age: 2 4 years; M:F = 3:1
Cause: failure of normal progression of cellular cartilage breakdown (= aclasis); spontaneous occurrence
Path: lobulated mass protruding from epiphysis with a cartilaginous cap
Histo: normal bone + hyaline cartilage with abundant enchondral ossification (= abnormal cellular activity at cartilaginous ossification center)

Types:

Location: lower extremity (tarsus, knee, ankle); rare in upper extremity (humerus, ulna, scapula)
Site: restricted to medial OR lateral side of limb (= hemimelic), ie, medial:lateral = 2:1
Cx: premature secondary osteoarthritis
DDx: osteochondroma

Echinococcus of Bone

Occurs occasionally in the USA; usually in foreign-born individuals; bone involvement in 1%

Histo: no connective tissue barrier; daughter cysts extend directly into bone

Ehlers-Danlos Syndrome

= group of autosomal dominant diseases of connective tissue characterized by abnormal collagen synthesis

Types: 10 types have been described that differ clinically, biochemically, and genetically
Age: present at birth; predominantly in males

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Elastofibroma

= benign tumorlike lesion forming as a reaction to mechanical friction

Incidence: in 24% of women + 11% of men >55 years (autopsy study)
Age: elderly; M:F = 1:2
Histo: enlarged irregular serrated elastic hypereosinophilic fibers, collagen, scattered fibroblasts, occasional lobules of adipose tissue

Enchondroma

= benign cartilaginous growth in medullary cavity; bones preformed in cartilage are affected (NOT skull)

Incidence: 3 17% of biopsied primary bone tumors

Second most common cartilage-containing tumor!
Etiology: continued growth of residual benign rests of cartilage displaced from the growth plate
Age: 10 30 years; M:F = 1:1
Histo: lobules of pure hyaline cartilage

usually asymptomatic, painless swelling

Location: (usually solitary; multiple = enchondromatosis)

(a) in 40% small tubular bones of wrists + hand (most frequent tumor here), distal + mid aspects of metacarpals, proximal / middle phalanges

(b) proximal femur, proximal humerus, tibia, radius, ulna, foot, rib (3%)
Site: central within medullary canal + metaphyseal; epiphysis only affected after closure of growth plate
Cx: (1) Pathologic fracture

(2) Malignant degeneration in long-bone enchondromas in 15 20% (gradually increasing pain in an adult patient)
DDx: (1) Epidermoid inclusion cyst (phalangeal tuft, history of trauma, more lucent)

(2) Unicameral bone cyst (rare in hands, more radiolucent)

(3) Giant cell tumor of tendon sheath (commonly erodes bone, soft-tissue mass outside bone)

(4) Fibrous dysplasia (rare in hand, mostly polyostotic)

(5) Bone infarct

(6) Chondrosarcoma (exceedingly rare in phalanges, metacarpals, metatarsals)

Enchondromatosis

Cause: derangement of cartilaginous growth resulting in migration of cartilaginous rests from epiphyseal plate into metaphysis where they proliferate
Age: early childhood presentation
Association: juvenile granulosa cell tumor of ovary
Location: predominantly unilateral monomelic distribution (a) localized (b) regional (c) generalized
Cx: sarcomatous transformation (in 25 30%): osteosarcoma (young adults); chondro- / fibrosarcoma (in older patients)

Maffucci Syndrome

Engelmann-Camurati Disease

= PROGRESSIVE DIAPHYSEAL DYSPLASIA = CAMURATI-ENGELMANN DISEASE

Cause: autosomal dominant; disturbance in intramembranous bone formation + modeling (as occurs in cortex of long bones, calvaria, mandible, facial bones, midsegment of clavicle)
Age: 5 25 years (primarily in childhood); M > F
Location: usually symmetrical; NO involvement of hands, feet, ribs, scapulae
DDx: (1) Chronic osteomyelitis (single bone)

(2) Hyperphosphatasemia (high alkaline phosphatase levels)

(3) Paget disease (age, new-bone formation, increased alkaline phosphatase)

(4) Infantile cortical hyperostosis (fever; mandible, rib, clavicles; regresses, <1 year of age)

(5) Fibrous dysplasia (predominantly unilateral, subperiosteal new bone)

(6) Osteopetrosis (very little bony enlargement)

(7) Vitamin A poisoning

Epidermoid Cyst

Epidermoid Inclusion Cyst

= INTRAOSSEOUS KERATIN CYST = IMPLANTATION CYST

Age: 2nd 4th decade; M > F
Histo: stratified squamous epithelium, keratin, cholesterol crystals (soft white cheesy contents)
Location: superficially situated bones such as calvarium (typically in frontal / parietal bone), phalanx (usually terminal tuft of middle finger), L > R hand, occasionally in foot
DDx: (a) in finger: glomus tumor, enchondroma (rare in terminal phalanx)

(b) in skull: infection, metastasis (poorly defined), eosinophilic granuloma (beveled margin)

Epiphyseolysis of Femoral Head

Frequency: 2:100,000 people
Etiology: growth spurt, renal osteodystrophy, rickets, childhood irradiation, growth hormone therapy, trauma (Salter-Harris type I epiphyseal injury)
Pathogenesis: widening of physeal plate during growth spurt + change in orientation of physis from horizontal to oblique increases shear forces
Age: overweight 8 17 year old boys (mean age for boys 13, for girls 11 years); M:F = 3:1; black > white

Associated with:

Location: usually unilateral; bilateral in 20 37% (at initial presentation in 9 18%)

Grading (based on femoral head position):

mild = displaced by <1/3 of metaphyseal diameter
moderate = displaced by 1/3 2/3 of diameter
severe = displaced by >2/3 of metaphyseal diameter
Cx: (1) Chondrolysis = acute cartilage necrosis (7 10%) = rapid loss of >50% of thickness of cartilage

    joint space <3 mm

(2) Avascular necrosis of femoral head (10 15%): risk increases with advanced degree of slip, delayed surgery for acute slip, anterior pin placement, large number of fixation pins, subcapital osteotomy

(3) Pistol-grip deformity = broadening + shortening of femoral neck in varus deformity

(4) Degenerative osteoarthritis (90%)

(5) Limb-length discrepancy due to premature physeal closure
Rx: (1) limitation of activity

(2) prophylactic pinning

(3) osteotomy

Attempted reductions increase risk of AVN!

Essential Osteolysis

= progressive slow bone-resorptive disease

Histo: proliferation + hyperplasia of smooth muscle cells of synovial arterioles
DDx: (1) Massive osteolysis = Gorham disease (local destruction of contiguous bones, usually not affecting hands / feet)

(2) Mutilating forms of rheumatoid arthritis

(3) Tabes dorsalis

(4) Leprosy

(5) Syringomyelia

(6) Scleroderma

(7) Raynaud disease

(8) Regional posttraumatic osteolysis

(9) Ulcero-mutilating acropathy

(10) Mutilating forms of rheumatoid arthritis

(11) Acrodynia mutilante (nonhereditary)

Ewing Sarcoma

= EWING TUMOR

Incidence: 4 10% of all bone tumors (less common than osteo- / chondrosarcoma); most common malignant bone tumor in children; 4th most common bone tumor overall
Histo: small round cells, uniformly sized + solidly packed (DDx: lymphoma, osteosarcoma, myeloma, neuroblastoma, carcinoma, eosinophilic granuloma) invading medullary cavity and entering subperiosteum via Haversian canals producing periostitis, soft-tissue mass, osteolysis; glycogen granules present (DDx to reticulum cell sarcoma); absence of alkaline phosphatase (DDx to osteosarcoma); MIC2 cell surface immunoreactivity (in 100%)
Age: peak 15 years (range 5 months to 54 years); in 95% 4 25 years; in 30% <10 years; in 39% 11 15 years; in 31% >15 years; in 50% <20 years;M:F = 1:2; Caucasians in 96%

Location:

Metastases to: lung, bones, regional lymph nodes in 11 30% at time of diagnosis, in 40 45% within 2 years of diagnosis
Cx: pathologic fracture (5 14%)
Prognosis: 60 75% 5-year survival
DDx: (1) Multiple myeloma (older age group)

(2) Osteomyelitis (duration of pain <2 weeks)

(3) Eosinophilic granuloma (solid periosteal reaction)

(4) Osteosarcoma (ossification in soft tissue, near age 20, no lamellar periosteal reaction)

(5) Reticulum cell sarcoma (clinically healthy, between 30 and 50 years, no glycogen)

(6) Neuroblastoma (< age 5)

(7) Anaplastic metastatic carcinoma (>30 years of age)

(8) Osteosarcoma

(9) Hodgkin disease

Extramedullary Hematopoiesis

Familial Idiopathic Acroosteolysis

Fanconi Anemia

Prognosis: fatal within 5 years after onset of anemia; patient's family shows high incidence of leukemia

Farber Disease

= DISSEMINATED LIPOGRANULOMATOSIS

Histo: foam cell granulomas; lipid storage of neuronal tissue (accumulation of ceramide + gangliosides)
Prognosis: death from respiratory failure within 2 years

Femoroacetabular impingement

= repetitive microtrauma due to an anatomic conflict between proximal femur + acetabular rim at extreme range of motion

Age: 2nd 3rd decade; in patients with increased sports activity

Femoroacetabular Impingement

P.77

Types:

Fibrochondrogenesis

= autosomal recessive lethal short-limb skeletal dysplasia

Incidence: 5 cases
Prognosis: stillbirth / death shortly after birth
DDx: (1) Thanatophoric dysplasia

(2) Metatropic dysplasia

(3) Spondyloepiphyseal dysplasia

Fibrodysplasia Ossificans Progressiva

Histo: edema with proliferating fibroblasts in a loose myxoid matrix; subsequent collagen deposition plus calcification + ossification of collagenized fibrous tissue in the center of nodules
Age: presenting by age 2 years (50%)
CAVE: surgery is hazardous causing accelerated ossification at the surgical site

Fibroma of Soft Tissue

Histo: hypocellular highly collagenic tumor
Age: 3rd and 4th decades; M > F
Location: tendon sheath of distal upper extremity

Fibrosarcoma

Incidence: 4% of all primary bone neoplasm

Etiology:

Histo: spectrum of well to poorly differentiated fibrous tissue proliferation; will not produce osteoid / chondroid / osseous matrix
Age: predominantly in 3rd 5th decade (range of 8 88 years); M:F = 1:1
Metastases to: lung, lymph nodes
Location: tubular bones in young, flat bones in older patients; femur (40%), tibia (16%) (about knee in 30 50%), jaw, pelvis (9%); rare in small bones of hand + feet or spinal column
Site: eccentric at diaphyseal-metaphyseal junction into metaphysis; intramedullary / periosteal
Cx: pathologic fracture (uncommon)
Prognosis: 20% 10-year survival
DDx: (1) Osteolytic osteosarcoma (2nd 3rd decade)

(2) Chondrosarcoma (usually contains characteristic calcifications)

(3) Aneurysmal bone cyst (eccentric blown-out appearance with rapid progression)

(4) Malignant giant cell tumor (begins in metaphysis extending toward joint)

Fibrous Cortical Defect

Incidence: 30% of children; M:F = 2:1
Age: peak age of 7 8 years (range of 2 10 years); mostly before epiphyseal closure
Histo: fibrous tissue from periosteum invading underlying cortex
Location: metaphyseal cortex of long bone; posterior medial aspect of distal femur, proximal tibia, proximal femur, proximal humerus, ribs, ilium, fibula

Prognosis:

Fibrous Dysplasia

Cause: probable gene mutation during embryogenesis
Age: 1st 2nd decade (highest incidence between 3 and 15 years), 75% before age 30; progresses until growth ceases; M:F = 1:1
Path: spongiosa of medullary cavity filled by abnormal fibrous tissue containing poorly calcified trabeculae
Histo: matrix of immature collagen contains small irregularly shaped trabeculae of immature, inadequately mineralized woven bone; trabeculae not rimmed by osteoblasts (DDx from ossifying fibroma); cartilaginous islands present in 10% (DDx: chondrosarcoma)

Clinical Types:

May be associated with:

VARIANT: McCune-Albright syndrome (10%)
Sex: almost exclusively in girls

Fibrous Histiocytoma

Benign Fibrous Histiocytoma

Incidence: 0.1% of all bone tumors
Histo: interlacing bundles of fibrous tissue in storiform pattern (whorled / woven) interspersed with mono- / multinucleated cells resembling histiocytes, benign giant cells, and lipid-laden macrophages; resembles nonossifying fibroma / fibroxanthoma
Age: 23 60 years
Location: long bone, pelvis, vertebra (rare)
Site: typically in epiphysis / epiphyseal equivalent
Rx: curettage
DDx: nonossifying fibroma (childhood / adolescence, asymptomatic, eccentric metaphyseal location)

Atypical Benign Fibrous Histiocytoma

Histo: atypical aggressive features = mitotic figures present
Prognosis: may metastasize

Malignant Fibrous Histiocytoma

= MFH = MALIGNANT FIBROUS XANTHOMA = XANTHO-SARCOMA = MALIGNANT HISTIOCYTOMA = FIBRO-SARCOMA VARIANT

Histo: spindle-cell neoplasm of a mixture of fibroblasts + giant cells resembling histiocytes with nuclear atypia and pleomorphism in pinwheel arrangement; closely resembles high-grade fibrosarcoma (= fibroblastic cells arranged in uniform pattern separated by collagen fibers)

(a) pleomorphic-storiform subtype (50 60%)

(b) myxoid subtype (25%)

(c) giant cell subtype (5 10%)

(d) inflammatory subtype (5 10%)

(e) angiomatoid subtype (<5%)
Age: 10 90 (average 50) years; peak prevalence in 5th decade; more frequent in Caucasians; M:F = 3:2
Location: potential to arise in any organ (ubiquitous mesenchymal tissue); soft tissues >> bone

Soft-tissue MFH

Incidence: 20 30% of all soft-tissue sarcomas; most common primary malignant soft-tissue tumor of late adult life
Location: extremities (75%), [lower extremity (50%), upper extremity (25%)], retroperitoneum (15%), head + neck (5%)
Site: within large muscle groups
Prognosis: larger + more deeply located tumors have a worse prognosis; 2-year survival rate of 60%; 5-year survival rate of 50%; local recurrence rate of 44%; metastatic rate of 42% (lung, lymph nodes, liver, bone)
DDx: (1) Liposarcoma (younger patient, presence of fat in >40%, calcifications rare)

(2) Rhabdomyosarcoma

(3) Synovial sarcoma (cortical erosion)

P.81

Osseous MFH

Prevalence: 5% of all primary malignant bone tumors
Associated with: prior radiation therapy, bone infarcts, Paget disease, fibrous dysplasia, osteonecrosis, fibroxanthoma (= nonossifying fibroma), enchondroma, chronic osteomyelitis
Location: femur (45%), tibia (20%), 50% about knee; humerus (10%); ilium (10%); spine; sternum; clavicle; rarely small bones of hand + feet
Site: central metaphysis of long bones (90%); eccentric in diaphysis of long bones (10%)
Cx: pathologic fracture (30 50%)
DDx: (1) Metastasis

(2) Fibrosarcoma (often with sequestrum)

(3) Reticulum cell sarcoma

(4) Osteosarcoma

(5) Giant cell tumor

(6) Plasmacytoma

Pulmonary MFH (extremely rare)

Focal Fibrocartilaginous Dysplasia of Tibia

Associated with: tibia vara
Age: 9 28 months
Histo: dense hypocellular fibrous tissue resembling tendon with lacuna formation
Location: insertion of pes anserinus (= tendinous insertion of gracilis, sartorius, semitendinosus muscles) distal to proximal tibial physis; unilateral involvement
Prognosis: resolution in 1 4 years
DDx: (1) Unilateral Blount disease (typically bilateral in infants, varus angulation of upper tibia, decreased height of medial tibial metaphysis, irregular physis)

(2) Chondromyxoid fibroma, eosinophilic granuloma, osteoid osteoma, osteoma, fibroma, chondroma (not associated with tibia vara, soft-tissue mass)

Fracture

= soft-tissue injury in which there is a break in the continuity of bone or cartilage

General description:

Special terminology:

avulsion Fx = fragment pulled off by tendon / ligament from parent bone
transchondral Fx = cartilaginous surface involved
chondral Fx = cartilage alone involved
osteochondral Fx = cartilage + subjacent bone involved

Description of anatomic positional changes:

NUC:

Pathologic Fracture

= fracture at site of preexisting osseous abnormality

Cause: tumor, osteoporosis, infection, metabolic disorder

Stress Fracture

= fractures produced as a result of repetitive prolonged muscular action on bone that has not accommodated itself to such action

Insufficiency Stress Fracture

= normal physiologic stress applied to bone with abnormal elastic resistance / deficient mineralization

Cause:

Location: thoracic vertebra, sacrum, pubic bone, ilium, lower extremity (calcaneus, tibia, fibula)
Fracture orientation: perpendicular to long axis of bone

Plain film / CT (1 2 weeks after onset of fracture):

MR:

NUC (bone scan):

Pelvic Insufficiency Stress Fracture

Incidence: 1.8 5% of women >55 years
Predisposed: postmenopausal women
Location: sacral ala, parasymphyseal region of os pubis, pubic rami, supraacetabular region, iliac blades, superomedial portion of ilium

Types:

NUC:

CT and MR (most accurate modalities):

Prognosis: healing in 12 30 months

Femoral Insufficiency Fracture

Site: subcapital

Fatigue Stress Fracture

X-RAY (15% sensitive in early fractures, increasing to 50% on follow-up):

P.84

NUC ( gold standard = almost 100% sensitive):

MR (very sensitive modality; fat saturation technique most sensitive as it detects an increase in water content of medullary edema / hemorrhage):

CT (least sensitive modality):

helpful in: longitudinal stress fracture of tibia; in confusing pediatric stress fracture (to detect endosteal bone formation)

DDx:

Epiphyseal Plate Injury

Prevalence: 6 18 30% of bone injuries in children <16 years of age
Peak age: 12 years
Location: distal radius (28%), phalanges of hand (26%), distal tibia (10%), distal phalanges of foot (7%), distal humerus (7%), distal ulna (4%), proximal radius (4%), metacarpals (4%), distal fibula (3%)
Mechanism: 80% shearing force; 20% compression
Resistance to trauma: ligament > bone > physis (hypertrophic zone most vulnerable)

Salter-Harris classification (considering probability of growth disturbance)

mnemonic: SALTR
Slip of physis = type 1
Above physis = type 2
Lower than physis = type 3
Through physis = type 4
Rammed physis = type 5

P.85

Salter Type 1 (6 8.5%)

Salter Type 2 (73 75%)

= shearing force splits growth plate

Line of fracture: through physis + extending through margin of metaphysis separating a triangular metaphyseal fragment (= corner sign )
Location: distal radius (33 50%), distal tibia + fibula, phalanges
Prognosis: good, may result in minimal shortening

Salter Type 3 (6.5 8%)

Salter Type 4 (10 12%)

Location: lateral condyle of humerus, distal tibia

Salter Type 5 (<1%)

Triplane Fracture (6%)

Location: distal tibia, lateral condyle of distal humerus

Apophyseal Injury

Mechanism: excessive avulsive force
DDx of healing acute injury: osteomyelitis, Ewing sarcoma

Hand Fracture

Bennett Fracture

Rx: anatomic reduction important, difficult to keep in anatomic alignment
Cx: pseudarthrosis

Boxer's Fracture

Mechanism: direct blow with clenched fist

Gamekeeper's Thumb

= SKIER'S THUMB (originally described as chronic lesion in hunters strangling rabbits)

P.86

Incidence: 6% of all skiing injuries; 50% of skiing injuries to the hand
Mechanism: violent abduction of thumb with injury to ulnar collateral ligament (UCL) in 1st MCP (faulty handling of ski pole)

Apophyseal Avulsion Injuries

Location Muscle Origin / Insertion
Anterior superior iliac spine sartorius muscle + tensor fasciae latae m.
Anterior inferior iliac spine rectus femoris muscle
Lesser trochanter iliopsoas muscle
Ischial tuberosity hamstrings
Greater trochanter gluteus medius + minimus, internal obturator, gemellus, piriformis
Iliac crest abdominal musculature
Symphysis pubis + inferior pubic ramus long + short adductors, gracilis

No Caption Available.

Navicular Fracture

Rolando Fracture

Prognosis: worse than Bennett's fracture (difficult to reduce)

No Caption Available.

Forearm Fracture

Barton Fracture

Chauffeur Fracture

Colles Fracture

Mechanism: fall on outstretched hand

Essex-Lopresti Fracture

Galeazzi Fracture

Mechanism: fall on outstretched hand with elbow flexed

Anterior Humeral Line and Elbow fat Pads

Monteggia-type Fracture

= fracture of ulnar shaft + dislocation of radial head

Bado Classification:

Smith Fracture

Mechanism: hyperflexion with fall on back of hand

Elbow Fracture

Rib Fracture

Associated with: pneumothorax, hemothorax, lung contusion / laceration

Malgaigne Fracture

P.89

Flail Chest

Cough Fracture

Location: 4 9th rib in anterior axillary line

Pelvic Fracture

Unstable pelvic fractures:

Acetabular Fracture

Anatomy & Function:

Classification (Judet and Letournel):

Duverney Fracture

Posterior wall (lip / rim) fracture (27%)

Mechanism: indirect force transmitted through length of femur with flexed hip joint (knee strikes dashboard)
Associated with: posterior dislocation of femur

Transverse fracture (9%)

N.B.: most difficult to diagnose + comprehend

Anterior column fracture (5%)

Mechanism: blow to greater trochanter with hip externally rotated
Associated with: posterior column / transverse fracture

Posterior column fracture (4%)

Mechanism: indirect force transmitted through length of femur with hip abducted
Associated with: posterior dislocation of femur + sciatic nerve injury

Anterior wall fracture (2%)

Mechanism: force transmitted through greater trochanter
Associated with: posterior dislocation of femur + sciatic nerve injury

Malgaigne Fracture

P.90

Tibial Plateau Fractures

Mechanism: direct trauma

Bucket Handle Fracture

Duverney Fracture

Knee Fracture

Segond Fracture

Tibial Plateau Fracture (Schatzker classification)

Mechanism: valgus force ( bumper / fender fracture from lateral force of automobile against a pedestrian's fixed knee) / compression force often in extension
Type I = wedge-shaped pure cleavage fracture 6%
Type II = combined cleavage + median compression fracture 25%
Type III = pure compression fracture 36%
Type IV = medial plateau fracture with a split /depressed comminution 10%
Type V = bicondylar fracture, often withinverted Y appearance 3%
Type VI = transverse / oblique fracture withseparation of metaphysis fromdiaphysis 20%

Foot Fracture

Ankle Fracture

Incidence: ankle injuries account for 10% of all emergency room visits; 85% of all ankle sprains involve lateral ligaments

Ligamentous connections at ankle:

Lateral Malleolar Fractures

Weber Type A

Weber Type B

Ankle Fractures

Maisonneuve Fracture

Weber Type C

Chopart Fracture

Jones Fracture

P.92

Peroneus Brevis Avulsion Fracture

Lisfranc Fracture

Shepherd Fracture

Calcaneal Fracture

Incidence: most commonly fractured tarsal bone; 60% of all tarsal fractures; 2% of all fractures in the body; commonly bilateral
Mechanism: fall from heights
May be associated with: lumbar vertebral fracture
Age: 95% in adults, 5% in children
adulthood: intraarticular (75%), extraarticular (25%)
childhood: extraarticular (63 92%)

No Caption Available.

Classification:

Frostbite

Cause: (1) cellular injury + necrosis from freezing process

(2) cessation of circulation secondary to cellular aggregates + thrombi forming as a result of exposure to low temperatures below 13 C (usually cold air)
Location: feet, hands (thumb commonly spared due to protection by clenched fist)

Early changes:

CHILD

ADULT

Angio:

Bone scintigraphy:

Rx: selective angiography with intraarterial reserpine

Ganglion

Ganglion cyst = mucin-containing cyst arising from tendon sheath / joint capsule / bursa / subchondral bone lined by flat spindle-shaped cells
Synovial cyst = cyst continuous with joint capsule lined by synovial cells (term is used by some synonymously with ganglion)

Soft-tissue Ganglion

= cystic tumorlike lesion usually attached to a tendon sheath

P.93

Origin: synovial herniation / coalescence of smaller cysts formed by myxomatous degeneration of periarticular connective tissue
Prognosis: may resolve spontaneously
Rx: steroid injection may improve symptomatology
DDx on MRI: myxoid lipoma, highly necrotic tumor

Intraosseous Ganglion

Periosteal Ganglion

Gardner Syndrome

Gaucher Disease

Dx: elevated serum activity of -glucocerebrosidase; genotyping
Cx: >90% have orthopedic complications at some time

(1) Pathologic fractures + compression fractures of vertebrae

(2) Avascular necrosis of femoral head, humeral head, wrist, ankle (common)

(3) Osteomyelitis (increased incidence)

(4) Myelosclerosis in long-standing disease

(5) Repeated pulmonary infections

(6) Cancer of hematopoietic origin (14.7-fold risk)
Prognosis: highly variable clinical course; strong relationship between splenic volume and disease severity
Rx: no cure; bone marrow transplantation; enzyme replacement therapy with Cerezyme
DDx: metastatic disease, multiple myeloma, leukemia, sickle-cell disease, fibrous dysplasia

Giant Cell Reparative Granuloma

= GIANT CELL REACTION = GIANT CELL GRANULOMA

Cause: ? reactive inflammatory process to trauma / infection (not a true neoplasm)
Histo: numerous giant cells in exuberant fibrous matrix arranged in clusters around foci of hemorrhage + commonly exhibiting osteoid formation (unusual in giant cell tumor); indistinguishable from brown tumor of HPT; cystic degeneration + ABC components distinctly uncommon
Peak age: 2nd + 3rd decade (ranging from childhood to 76 years); 74% <30 years of age; M:F = 1:1
May be associated with: enchondromatosis, Goltz syndrome, fibrous dysplasia, Paget disease

Location:

Cx: pathologic fracture
Prognosis: may recur; no malignant transformation
Rx: curettage (22 50% recurrence rate) / local excision
DDx: (1) Enchondroma (same location, matrix calcification)

(2) Aneurysmal bone cyst (rare in small bones of hand + feet, typically prior to epiphyseal closure)

(3) Giant cell tumor (more aggressive appearance)

(4) Infection (clinical)

(5) Brown tumor of HPT (periosteal bone resorption, abnormal Ca + P levels)

P.95

Giant Cell Tumor

Origin: probably arise from zone of intense osteoclastic activity (of endochondral ossification) in skeletally immature patients
Incidence: 4 9.5% of all primary bone tumors; 18 23% of benign skeletal tumors; unusually high prevalence in China + southern India
Path: friable vascular stroma of numerous thin-walled capillaries with necrosis + hemorrhage + cyst formation (DDx: aneurysmal bone cyst without solid areas)
Histo: large number of multinucleated osteoclastic giant cells in a diffuse distribution in a background of mononuclear cells intermixed throughout a spindle cell stroma (DDx: giant cells characteristic of all reactive bone disease as in pigmented villonodular synovitis, benign chondroblastoma, nonosteogenic fibroma, chondromyxoid fibroma, fibrous dysplasia)
Age: peaks in 3rd decade; 1 3% < age 14; 80% between 20 and 50 years; 9 13% > age 50; M:F = 1:1.1 to 1:1.5 (in spine 1:2.5)
May be associated with: Paget disease (in 50 60% located in skull + facial bones)

Staging:

Stage 1 indolent radiographic + histologic appearance (10 15%)
Stage 2 more aggressive radiographic appearance with expansile remodeling (70 80%)
Stage 3 extension into adjacent soft tissues with histologically benign appearance (10 15%)

Location:

Cx: in 5 10% malignant transformation within first 5 years (M:F = 3:1); metastases to lung
Prognosis: locally aggressive; 80 90% recurrence rate within first 3 years after initial treatment
Rx: currettage + bone grafting (40 60% recurrence); currettage with filling of void with high-speed burr + polymethylmethacrylate (2 25% recurrence); wide resection (7% recurrence) and reconstruction with allografts / metal prosthesis; radiation therapy for inoperable GCT (39 63% recurrence)
DDx: (1) Aneurysmal bone cyst (contains only cystic regions; in posterior elements of spine)

(2) Brown tumor of HPT (lab values)

(3) Osteoblastoma

(4) Cartilage tumor: chondroblastoma, enchondroma (not epiphyseal), chondromyxoid fibroma, chondrosarcoma

(5) Nonossifying fibroma

(6) Bone abscess

(7) Hemangioma

(8) Fibrous dysplasia

(9) Giant cell reparative granuloma

Multifocal Giant Cell Tumor

= additional GCTs (up to a maximum of 20) developing synchronously / metachronously for up to 20 years without increased risk of pulmonary metastases

Incidence: <1% of all GCT cases
Age: 25 years (range, 11 62 years); M<F
May be associated with: Paget disease, usually polyostotic (GCT develops at a mean age of 61 years + after an average time lapse of 12 years) with involvement of skull + facial bones
Location: increased prevalence of hands + feet

Malignant Giant Cell Tumor

= group of giant cell containing lesions capable of malignant behavior + pulmonary metastases

Prevalence: 5 10% of all GCTs
Age: older than patients with benign GCTs

Types:

Glomus Tumor

Gout

= characterized by derangement of purine metabolism manifested by:

P.97

Age: >40 years; males (in women gout may occur after menopause)

Cause:

Histo: tophus (PATHOGNOMONIC LESION) composed of crystalline / amorphous urates surrounded by highly vascularized inflammatory tissue rich in histiocytes, lymphocytes, fibroblasts, foreign-body giant cells (similar to a foreign-body granuloma)

Clinical stages in chronologic order:

Location:

Rx: colchicine, allopurinol (effective treatment usually does not improve roentgenograms)

DDx:

Granulocytic Sarcoma

Gunshot Injury

Firearms: handgun, rifle (great energy), shotgun

Projectiles:

Assessment:

Cx: pellet embolization, magnetization in MRI

Hemangioendothelial sarcoma

Soft-tissue Hemangioendothelioma (common)

Location: deep tissues of extremities
Site: in 50% closely related to a vessel (often a vein)

Osseous Hemangioendothelioma (rare)

Age: 2nd 3rd decade of life; M > F
Location: calvarium, spine, femur, tibia, humerus, pelvis; multicentric lesions in 30% often with regional distribution (less aggressive)
Metastases to: lung (early)
Prognosis: 26% 5-year survival rate
DDx: aneurysmal bone cyst, poorly differentiated fibrosarcoma, highly vascular metastasis, alveolar rhabdomyosarcoma

Hemangioma

Histo: frequently containing variable amounts of nonvascular elements: fat, smooth muscle, fibrous tissue, bone, hemosiderin, thrombus

Fat overgrowth may be so extensive that some lesion may be misdiagnosed as a lipoma!

Osseous Hemangioma

Incidence: 10%
Histo: mostly cavernous; capillary type is rare
Age: 4th 5th decade; M:F = 2:1

Soft-tissue Hemangioma

Incidence: 7% of all benign tumors; most frequent tumor of infancy + childhood
Age: primarily in children; M < F
May be associated with: Maffucci syndrome (= multiple cavernous hemangiomas + enchondromas)

Synovial Hemangioma

Hemangiopericytoma

Hemochromatosis

= excess iron deposition in tissues (hemosiderosis) resulting in tissue injury

Primary / Idiopathic Hemochromatosis

Dx: liver biopsy with hepatic iron index > 2 (= iron concentration in mol/g of dry weight divided by patient's age in years)
Cx: hepatoma in 14% (iron stimulates growth of neoplasms)
Prognosis: death from CHF (30%), death from hepatic failure (25%), death from HCC (in up to 33%)
Rx: (1) Phlebotomy (return of life expectancy to normal if instituted prior to complications)

(2) Screening of family members (gene can be located by human leukocyte antigen typing)
DDx: Pseudogout (no arthropathy)

(2) Psoriatic arthritis (skin + nail changes)

(3) Osteoarthritis (predominantly distal joints in hands)

(4) Rheumatoid arthritis

(5) Gout (may also have chondrocalcinosis)

Secondary Hemochromatosis

= nongenetic iron overload

Transfusional Siderosis

Hemolytic Anemia

Cause:

Reconversion = recruitment of yellow marrow for hematopoiesis once hematopoietic capacity of existing red marrow stores is exceeded

Order of reconversion: spine > flat bones > skull > long bones (proximal > distal metaphysis > diaphysis > epi- / apophyses)

MR:

Cx:

DDx: leukemia (hyperintense on STIR)

Hemophilia

= X-linked deficiency / functional abnormality of coagulation factor VIII (= hemophilia A) in >80% / factor IX (= hemophilia B = Christmas disease)

Incidence: 1:10,000 males

Hemophilic Arthritis

P.102

Hemophilic Arthropathy (most common)

Cause: repeated bleeding into synovial joint
Path: pannus formation erodes cartilage with loss of subchondral bone plate and formation of subarticular cysts
Histo: synovial hyperplasia, chronic inflammatory changes, fibrosis, siderosis of synovial membrane
Age: 1st and 2nd decade

Hemophilic Pseudotumor (1 2%)

Cx: joint contracture (after repeated bleeding into muscle)
N.B.: Needle aspiration / biopsy / excision may cause fistulae / infection / uncontrolled bleeding!
Rx: palliative radiation therapy (destroys vessels prone to bleed) + transfusion of procoagulation factor concentrate

Hereditary hyperphosphatasia

Hereditary Multiple Diaphyseal Sclerosis

Hereditary Spherocytosis

Herniation Pit

Holt-Oram Syndrome

Autosomal dominant; M < F

Associated with CHD: secundum type ASD (most common), VSD, persistent left SVC, tetralogy, coarctation

Homocystinuria

Autosomal recessive disorder

Etiology: cystathionine B synthetase deficiency results in defective methionine metabolism with accumulation of homocystine + homocysteine in blood and urine; causes defect in collagen / elastin structure

Hyperparathyroidism

Sequelae:

Primary Hyperparathyroidism

Incidence: 25:100,000 per year; incidence of bone lesions in HPT is 25 40%

Etiology:

Histo: increased number of osteoclasts, increased osteoid volume (defect in mineralization), slightly increased osteoblasts = decreased bone mass
Age: 3rd 5th decade; M:F = 1:3

Associated with:

X-RAY (skeletal involvement in 10 20%):

NUC:

Rx: pathologic glands identified by experienced surgeons in 90 95% on initial neck exploration (ectopic + supernumerary glands often overlooked at operation; recurrent hypercalcemia in 3 10%)

Surgical risk for repeat surgery:

6.6% recurrent laryngeal nerve injury
20.0% permanent hypoparathyroidism
<1.0% perioperative mortality

Secondary Hyperparathyroidism

Tertiary Hyperparathyroidism

Ectopic Parathormone Production

= pseudohyperparathyroidism as paraneoplastic syndrome in bronchogenic carcinoma + renal cell carcinoma

P.106

Hypertrophic Osteoarthropathy

Etiology: (1) Release of vasodilators which are not metabolized by lung

(2) Increased flow through AV shunts

(3) Reflex peripheral vasodilation (vagal impulses)

(4) Hormones: estrogen, growth hormone, prostaglandin
Histo: round cell infiltration of the outer fibrous layer of periosteum followed by new bone proliferation
Location: tibia + fibula (75%), radius + ulna (80%), proximal phalanges (60%), femur (50%), metacarpus + metatarsus (40%), humerus + distal phalanges (25%), pelvis (5%); unilateral (rare)

Spine, pelvis, ribs usually spared!
Site: in diametaphyseal regions
Prognosis: treatment of underlying condition leads to remission of symptoms often within 24 hours + regression of radiographic findings in months
DDx: (1) Pachydermoperiostosis (self-limited, adolescence, autosomal dominant, M>F)

(2) Metastases (axial skeleton, focal asymmetric distribution)

(3) Chronic vascular insufficiency

(4) Thyroid acropachy

(5) Hypervitaminosis A

Hypervitaminosis A

Age: usually infants + children
Cause: overdosing vitamin A, 13-cis-retinoic acid (treatment for neuroblastoma)

Hypervitaminosis D

Hypoparathyroidism

Idiopathic Hypoparathyroidism

Secondary Hypoparathyroidism

Hypophosphatasia

= autosomal recessive congenital disease with low activity of serum-, bone-, liver-alkaline phosphatase resulting in poor mineralization (deficient generation of bone crystals)

Incidence: 1:100,000
Histo: indistinguishable from rickets

Hypothyroidism

Hypothyroidism during Childhood = Cretinism

Frequency: 1:4,000 live births have congenital hypothyroidism
Cause: sporadic hypoplasia / ectopia of thyroid

Hypothyroidism during Adulthood

Differences between Various Types of Hypothyroidism

  HypoPT Pseudo HypoPT Pseudopseudo HypoPT
Serum Ca
Serum P
AlkaPhos or or
Response to PTH-Injection
Urine AMP  
Urine P  
Plasma AMP  

P.108

Infantile Cortical Hyperostosis

Chronic Infantile Hyperostosis

Iron Deficiency Anemia

Age: infants affected
Cause: (1) inadequate iron stores at birth

(2) deficient iron in diet

(3) impaired gastrointestinal absorption of iron

(4) excessive iron demands from blood loss

(5) polycythemia vera (6) cyanotic CHD

Jaccoud Arthropathy

After subsidence of frequent severe attacks of rheumatic fever

Path: periarticular fascial + tendon fibrosis without synovitis
Location: primarily involvement of hands; occasionally in great toe

Klinefelter Syndrome

47, XXY (rarely XXYY) chromosomal abnormality

Incidence: 1:750 live births (probably commonest chromosomal aberration)

47, XXX = Superfemale Syndrome

Klippel-Trenaunay Syndrome

Cx: thrombophlebitis, deep venous thrombosis, pulmonary embolism, lymphangitis
Rx: (1) conservative: application of graded compressive stockings, pneumatic compression devices, percutaneous sclerosis of localized venous malformations / superficial varicosities

(2) surgical: epiphysiodesis, excision of soft-tissue hypertrophy, vein stripping
DDx: (1) Parke-Weber syndrome

   = congenital persistence of multiple microscopic AV fistulas + spectrum of Klippel-Trenaunay-Weber syndrome (pulsatility, thrill, bruit)

(2) Neurofibromatosis (caf -au-lait spots, axillary freckling, cutaneous neurofibromas, macrodactyly secondary to plexiform neurofibromas, wavy cortical reaction, early fusion of growth plate, limb hypertrophy not as extensive / bilateral)

(3) Beckwith-Wiedemann syndrome (aniridia, macroglossia, cryptorchidism, Wilms tumor, broad metaphyses, thickened long-bone cortex, advanced bone age, periosteal new-bone formation, hemihypertrophy)

(4) Macrodystrophia lipomatosis (hyperlucency of fat, distal phalanges most commonly affected, overgrowth ceases with puberty, usually limited to digits)

(5) Maffucci syndrome (cavernous hemangiomas, soft tissue hypertrophy, phleboliths, multiple enchondromas)

Labral Tears of Shoulder

Anterior Labral Tear

Location: anteroinferior labrum > entire anterior labrum > isolated tear of anterosuperior labrum
DDx: (1) Middle + inferior glenohumeral ligaments closely apposed to anterior labrum

(2) Recess between anterior labrum + glenoid rim

(3) Recess between middle + inferior ligaments

Slap Lesion

P.110

SLAP I = fraying of superior labrum; common in elderly as a degenerative tear
SLAP II = detachment of superior biceps-labral complex from glenoid rim

DDx: superior sublabral recess (less distance between labrum + glenoid, no irregular appearance, no lateral extension of defect)
SLAP III = bucket-handle tear of superior labrum leaving biceps tendon attached to glenoid
SLAP IV = bucket-handle tear of superior labrum with tear extending into biceps tendon
SLAP V = Bankart lesion dissecting upward to involve the biceps tendon
SLAP VI = unstable radial / flap tear with separation of biceps anchor
SLAP VII = superior labral tear extending into middle glenohumeral ligament
SLAP VIII = SLAP II + entire posterior labral tear; anterior inferior labrum not involved
SLAP IX = circumferential labral tear

Superior Labrum Anterior-to-Posterior Lesions

Langerhans cell histiocytosis

Cause: uncertain (? primary proliferative disorder possibly due to defect in immunoregulation; neoplasm; virus)
Path: influx of eosinophilic leukocytes simulating inflammation; reticulum cells accumulate cholesterol + lipids (= foam cells); sheets or nodules of histiocytes may fuse to form giant cells, cytoplasm contains (? viral) Langerhans bodies
Histo: Langerhans cells are similar to mononuclear macrophages + dendritic cells as the two major types of nonlymphoid mononuclear cells involved in immune + nonimmune inflammatory response; derived from promonocytes (= bone marrow stem cell)
Age: any age, mostly presenting at 1 4 years; M:F = 1:1
Location: bone + bone marrow, lymph nodes, thymus, ear, liver and spleen, gallbladder, GI tract, endocrine system
DDx: osteomyelitis, Ewing sarcoma, leukemia, lymphoma, metastatic neuroblastoma

Clinical manifestations:

Eosinophilic Granuloma (70%)

Prognosis: excellent with spontaneous resolution of bone lesions in 6 18 months

Hand-Sch ller-Christian Disease (20%)

Letterer-Siwe Disease (10%)

Prognosis: rapidly progressive with 70% mortality rate

Lateral Epicondylitis

Rx: (1) conservative management: avoidance of painful activity, application of ice, NSAID

(2) splints, steroid injection

(3) excision of abnormal tissue + decortication of epicondyle + reattachment of tendon
DDx of painful elbow: injury to radial collateral ligament / extensor carpi radialis longus tendon, cartilage defect

Laurence-Moon-Biedl Syndrome

Lead Poisoning

DDx: (1) Healed rickets

(2) Normal increased density in infants <3 years of age

Leprosy

Leukemia of Bone

Lipoblastoma

Rx: complete excision with tendency to recur in 10 25%
DDx: liposarcoma (extremely rare in children), dermoid cyst

Lipoma of Bone

DDx: fibrous dysplasia, simple bone cyst, posttraumatic cyst, giant cell tumor, desmoplastic fibroma, chondromyxoid fibroma, osteoblastoma

Lipoma of Soft Tissue

Most common mesenchymal tumor composed of mature adipose tissue

Histo: mature fat cells (adipocytes) that are uniform in size + shape, occasionally have fibrous connective tissue as septations; fat unavailable for systemic metabolism

Angiolipoma

Benign Mesenchymoma

Infiltrating Lipoma

Peak age: 5th 6th decade; M > F
Location: thigh (50%), shoulder, upper arm

Lipoma Arborescens

Location: knee; monoarticular
Frequently associated with: degenerative joint disease, chronic rheumatoid arthritis, prior trauma

Neural Fibrolipoma

DDx: cyst, ganglion, lipoma, traumatic neuroma, plexiform neurofibroma, vascular malformation

Liposarcoma

Lyme Arthritis

Agent: spirochete Borrelia burgdorferi; transmitted by tick Ixodes dammini
Histo: inflammatory synovial fluid, hypertrophic synovia with vascular proliferation + cellular infiltration

Lymphangioma

Age: found at birth (50 65%); within first 2 years of life (90%)
Location: soft tissue; bone (rare)

Lymphangiomatosis of bone

Lymphoma of Bone

Macrodystrophia Lipomatosa

Marfan Syndrome

Melorheostosis

Orientation of Meniscal Tears

Meniscal Tear

Cause: acute injury, degeneration related to aging

Type of cross-sectional tear pattern:

Type of arthroscopic surface pattern:

Site of injury:

Associated with: ligamentous injury

PITFALLS:

Mesomelic Dwarfism

Metaphyseal Chondrodysplasia

Metastases to Bone

P.120

Frequency:

If primary known If primary unknown
Breast 35% Prostate 25%
Prostate 30% Lymphoma 15%
Lung 10% Breast 10%
Kidney 5% Lung 10%
Uterus 2% Thyroid 2%
Stomach 2% Colon 1%
Others 13%    

SOLITARY BONE LESION

Location: axial skeleton (64 68%), ribs (45%), extremities (24%), skull (12%)
mnemonic: Several Kinds Of Horribly Nasty Tumors Leap Promptly To Bone
Breast cancer: extensive osteolytic lesions; involvement of entire skeleton; pathologic fractures common
Thyroid / kidney: often solitary; rapid progression with bone expansion (bubbly); frequently associated with soft-tissue mass (distinctive)
Rectum / colon: may resemble osteosarcoma with sunburst pattern + osteoblastic reaction
Hodgkin tumor: upper lumbar + lower thoracic spine, pelvis, ribs; osteolytic / occasionally osteoblastic lesions
Osteosarcoma: 2% with distant metastases, adjuvant therapy has changed the natural history of the disease in that bone metastases occur in 10% of osteosarcomas without metastases to the lung
Ewing sarcoma: extensive osteolytic / osteoblastic reaction (13% with distant metastases)
Neuroblastoma: extensive destruction, resembles leukemia (metaphyseal band of rarefaction), mottled skull destruction + increased intracranial pressure, perpendicular spicules of bone
Mode of spread: through bloodstream / lymphatics / direct extension
Location: predilection for marrow-containing skeleton (skull, spine, ribs, pelvis, humeri, femora)

Osteolytic Bone Metastases

Most common cause: neuroblastoma (in childhood); lung cancer (in adult male); breast cancer (in adult female), thyroid cancer; kidney; colon

Osteoblastic Bone Metastases

Mixed Bone Metastases

breast, prostate, lymphoma

Expansile / Bubbly Bone Metastases

kidney, thyroid

Permeative Bone Metastases

Burkitt lymphoma, mycosis fungoides

Bone Metastases with Sunburst Periosteal Reaction

Bone Metastases with Soft-tissue Mass

thyroid, kidney

Calcifying Bone Metastases

mnemonic: BOTTOM

Skeletal Metastases in Children

P.121

Skeletal Metastases in Adult

mnemonic: Common Bone Lesions Can Kill The Patient

Role of Bone Scintigraphy in Bone Metastases

Pathophysiology: accumulation of tracer at sites of reactive bone formation
False-negative scan: very aggressive metastases
False-positive scan: degeneration, healing fractures, metabolic disorders
DDx: pulmonary metastasis (SPECT helpful in distinguishing nonosseous lung from overlying rib uptake)

Role of Bone Scan in Breast Cancer

Role of Bone Scan in Prostate Cancer

Stage B: 5% with skeletal metastases
Stage C: 10% with skeletal metastases
Stage D: 20% with skeletal metastases

Role of Magnetic Resonance Imaging in Bone Metastases

in children: proximal + distal metaphyses of long bones, flat bones, spine
in adults: calvarium, spine, flat bones, proximal humeral + femoral metaphyses

Metatrophic Dysplasia

P.122

Prognosis: compatible with life, increased disability from kyphoscoliosis
DDx: achondroplasia, mucopolysaccharidoses

Methotrexate Osteopathy

Morton Neuroma

Rx: conservative treatment; surgical excision for neuromas >5 mm in transverse diameter (more commonly symptomatic)

Mucopolysaccharidoses

Cx: cord compression at atlantoaxial joint (types IV + VI)
Dx: combination of clinical features, radiographic abnormalities correlated with genetic + biochemical studies
Prenatal Dx: occasionally successful analysis of fibroblasts cultured from amniotic fluid
DDx: Gaucher disease, Niemann-Pick disease

Hurler Syndrome

Prognosis: death by age 10 15 years

Morquio Syndrome

Incidence: 1:40,000 births
Etiology: N-acetyl-galactosamine-6-sulfatase deficiency resulting in defective degradation of keratin sulfate (mainly in cartilage, nucleus pulposus, cornea)
Age: normal at birth; skeletal changes manifest within first 18 months; M:F = 1:1
Cx: cervical myelopathy (traumatic quadriplegia / leg pains / subtle neurologic abnormality) most common cause of death secondary to C2 abnormality; frequent respiratory infections (from respiratory paralysis)
Rx: early fusion of C1 C2
Prognosis: may live to adulthood (3rd 4th decade)
DDx: (1) Hurler syndrome (normal / increased vertebral height; vertebral beak inferior)
  (2) Spondyloepiphyseal dysplasia (autosomal dominant, present at birth, absent flared ilia / deficient acetabular ossification, small acetabular angle, deficient ossification of pubic bones, varus deformity of femoral neck, minimal involvement of hand + foot, myopia)

Multiple Epiphyseal Dysplasia

DDx: Legg-Perthes disease, hypothyroidism

Multiple Myeloma

Myelomatosis

Musculotendinous Injury

Muscle Contusion

Cause: direct trauma, usually by blunt object
Site: deep within muscle belly

Myotendinous Strain

Cause: single traumatic event from excessive stretching

Acute Avulsion Injury

Cause: forceful unbalanced often eccentric muscle contraction
Path: periosteal stripping with hematoma at tendon attachment site
Site: at tendon insertion

Myelofibrosis

DDx: (1) With splenomegaly: chronic leukemia, lymphoma, mastocytosis
  (2) Without splenomegaly: osteoblastic metastases, fluorine poisoning, osteopetrosis, chronic renal disease

Myeloid Depletion

Myeloproliferative Disorders

Myositis Ossificans

Myositis Ossificans Variants

Panniculitis Ossificans

Location: subcutis of mostly upper extremities

Fasciitis Ossificans

Location: fascia

Fibroosseous Pseudotumor of Digits

Rx: local excision
DDx: parosteal / periosteal osteogenic sarcoma, peripheral chondrosarcoma, periosteal chondroma, soft-tissue chondroma

Nail-patella syndrome

DDx: (1) Seckel syndrome = bird-headed dwarfism
  (2) Popliteal pterygium syndrome (absence of patella, toenail dysplasia)

Necrotizing Fasciitis

Incidence: 500 cases in literature
Age: 58 14 years; M>F
Cause: deep internal infection / malignancy (perforated duodenal ulcer / retroperitoneal appendix, retroperitoneal / perirectal infection, infiltrating rectal / sigmoid carcinoma
Predisposed: patients with diabetes, cancer, alcohol / drug abuse, poor nutrition
Organism: Staphylococcus, E. coli, Bacteroides, Streptococcus, Peptostreptococcus, Klebsiella, Proteus, C. perfringens (5 15%) (multiple organisms in 75%)
Histo: necrotic superficial fascia, leukocytic infiltration of deep fascial layers; fibrinoid thrombosis of arterioles + venules with vessel wall necrosis; microbial infiltration of destroyed fascia

P.128

Prognosis: poor with delay in diagnosis
Rx: extensive surgical d bridement
DDx: (1) Myonecrosis (infection originating in muscle)
  (2) Fasciitis-panniculitis syndromes (chronic swelling of skin + underlying soft tissues + fascial planes in arm + calf)
  (3) Soft-tissue edema of CHF / cirrhosis (symmetrical diffuse fat stranding)

Neuropathic Osteoarthropathy

DDx: osteomyelitis, septic arthritis (usually involve single joint)

Nodular Tenosynovitis

DDx: (1) Florid proliferative synovitis (diffuse infiltrative form of GCT = extraarticular subtype of PVNS)
  (2) Pigmented villonodular synovitis
  (3) Desmoid tumor
  (4) Malignant fibrous histiocytoma

Nonossifying Fibroma

CAVE: lesions >33 mm long involving >50% of the transverse bone diameter need observation
Prognosis: spontaneous healing in most cases
Cx: (1) Pathologic fracture (not uncommon)
  (2) Hypophosphatemic vitamin D resistant rickets + osteomalacia (tumor may secrete substance that increases renal tubular resorption of phosphorus)
DDx: (1) Adamantinoma (midshaft of tibia)
  (2) Chondromyxoid fibroma (bulging of cortex more striking, hyperintense on T2WI)
  (3) Fibrous dysplasia (internal septations rare)
  (4) Aneurysmal bone cyst (heterogeneously hyperintense with fluid-fluid levels)
  (5) Intraosseous ganglion (hyperintense on T2WI)

Multiple Fibroxanthomas (in 8 10%)

Associated with: neurofibromatosis, fibrous dysplasia, Jaff -Campanacci syndrome

Jaff -Campanacci Syndrome

Noonan Syndrome

DDx: Turner syndrome (mental retardation rare, renal anomalies frequent)

Ochronosis

Orodigitofacial Syndrome

Osgood-Schlatter Disease

Cx: nonunion of bone fragment, patellar subluxation, chondromalacia, avulsion of patellar tendon, genu recurvatum
Rx: immobilization / steroid injection
DDx: (1) Normal ossification pattern of tibial tuberosity between ages 8 14 (no symptoms)
  (2) Osteitis: tuberculous / syphilitic
  (3) Soft-tissue sarcoma with calcifications

Ossifying fibroma

Cx: frequent recurrences

Osteitis Condensans ILII

Incidence: 2% of population
Cause: chronic stress secondary to instability of pubic symphysis
Age: young multiparous women
DDx: (1) Ankylosing spondylitis (affects ilium + sacrum, joint space narrowing, involvement of other bones)
  (2) Rheumatoid arthritis (asymmetric, joint destruction)
  (3) Paget disease (thickened trabecular pattern)

Osteoarthritis

DDx: osteoblastic metastasis

Erosive Osteoarthritis

DDx: Rheumatoid arthritis, Wilson disease, chronic liver disease, hemochromatosis

Early Osteoarthritis

mnemonic: Early OsteoArthritis

Milwaukee Shoulder

Rapidly Destructive Articular Disease

Osteoblastoma

Osteochondroma

Osteochondromatous Variants

Solitary Osteochondroma

Frequency: 1 2%; M:F = 1.6:1 3.4:1
  20 50% of benign bone tumors;
  10 15% of all bone tumors
Age: 1st 3rd decade; M:F = 1.5:1
Site: metaphysis of long bones; rarely diaphysis
Location: in any bone that develops by enchondromal calcification; femur (30%), tibia (15 20%), about knee (40%), humerus (10 20%), hands and feet (10%), pelvis (5%), scapula (4%), rib (3%), spine (2%, cervical [esp. C2] > thoracic [T8 > T4] > lumbar)
Type: (a) pedunculated osteochondroma = narrow stalk
  (b) sessile osteochondroma = broad base

Hereditary Multiple Exostoses

Osteochondrosis Dissecans

DDx: spontaneous osteonecrosis, neuroarthropathy, degenerative joint disease, synovial osteochondromatosis

Osteochondritis Dissecans of Capitellum

Age: adolescent boys 13 16 years of age
Cause: overhead throwing activity / gymnastics

Osteofibrous Dysplasia

Cx: pathologic fracture in 25%, fractures will heal with immobilization; infrequently complicated by pseudarthrosis
DDx: fibrous dysplasia, Paget disease

Osteogenesis Imperfecta

Cx: (1) Impaired hearing / deafness from otosclerosis (20 60%)
  (2) Death from intracranial hemorrhage (abnormal platelet function)
Dx: chorionic villous sampling

P.136

Osteogenesis Imperfecta Type I

Osteogenesis Imperfecta Type II

Prognosis: stillborn / death shortly after birth due to pulmonary hypoplasia
DDx: congenital hypophosphatasia; achondrogenesis type I; camptomelic dysplasia

Osteogenesis Imperfecta Type III

Prognosis: progressive limb + spine deformities during childhood / adolescence

Osteogenesis Imperfecta Type IV

Transmission: autosomal dominant; mildest form with best prognosis

Osteoid Osteoma

Cortical osteoid osteoma (most common)

Cancellous Osteoid Osteoma (intermediate frequency)

Subperiosteal Osteoid Osteoma (rare)

Osteoma

Fibrous Osteoma

Osteomyelitis

Acute Osteomyelitis

Age: most commonly affects children
Cx: (1) Soft-tissue abscess
  (2) Fistula formation
  (3) Pathologic fracture
  (4) Extension into joint
  (5) Growth disturbance due to epiphyseal involvement
  (6) Neoplasm
  (7) Amyloidosis
  (8) Severe deformity with delayed treatment

Acute Neonatal Osteomyelitis

Age: onset <30 days of age

Acute Osteomyelitis in Infancy

Age: <18 months of age
Pathomechanism: spread to epiphysis because transphyseal vessels cross growth plate into epiphysis
Cx: frequent joint involvement
Prognosis: rapid healing

P.139

Acute Osteomyelitis in Childhood

Age: 2 16 years of age

Acute Osteomyelitis in Adulthood

Associated with: soft-tissue abscess, pathological fracture
Risk factors: IV drug use, previous trauma, immunosuppressed state, diabetes

Diabetic foot

Cause: callus / minor skin trauma (eg, toenail cutting)
Pathophysiology: pressure points callus ulceration osteomyelitis
DDx: Neuropathic osteoarthropathy (dislocation, disorganizaton, debris, destruction, density preserved; mildly symptomatic, joint effusion, multiple joints involved, marrow edema, periarticular enhancement; more common in ankle / Lisfranc / Chopart joints)

Chronic Osteomyelitis

Sclerosing Osteomyelitis of Garr

Chronic Recurrent Multifocal Osteomyelitis

Brodie Abscess

DDx: Osteoid osteoma

Epidermoid Carcinoma

Etiology: complication of chronic osteomyelitis (0.2 1.7%)
Histo: squamous cell carcinoma (90%); occasionally: basal cell carcinoma, adenocarcinoma, fibro-sarcoma, angiosarcoma, reticulum cell sarcoma, spindle cell sarcoma, rhabdomyosarcoma, parosteal osteosarcoma, plasmacytoma
Age: 30 80 (mean 55) years; M >> F
Latent period: 20 30 (range of 1.5 72) years

Osteopathia Striata

Osteopetrosis

Path: defective osteoclast function with failure of proper reabsorption + remodeling of primary spongiosa; bone sclerotic + thick but structurally weak + brittle
Cx: (1) Usually transverse fractures (common because of brittle bones) with abundant callus + normal healing
  (2) Crowding of marrow (myelophthisic anemia + extramedullary hematopoiesis)
  (3) Frequently terminates in acute leukemia
Rx: bone marrow transplant
DDx: (1) Heavy metal poisoning
  (2) Melorheostosis (limited to one extremity)
  (3) Hypervitaminosis D
  (4) Pyknodysostosis
  (5) Fibrous dysplasia of skull / face

Infantile Autosomal Recessive Osteopetrosis

Benign Adult Autosomal Dominant Osteopetrosis

Cause: defect on chromosome 1p21
Prognosis: normal life expectancy

Osteopoikilosis

Prognosis: not progressive, no change after cessation of growth
DDx: (1) Epiphyseal dysplasia (metaphyses normal)
  (2) Melorheostosis (diaphyseal involvement)
  (3) Mastocytosis
  (4) Tuberous sclerosis
  (5) Osteoblastic metastases

Osteosarcoma

Extraskeletal Osteosarcoma

High-grade Intramedullary Osteosarcoma

DDx: Osteoid osteoma, sclerosing osteomyelitis, Charcot joint

High-grade Surface Osteosarcoma

Location: femur, humerus, fibula
Site: diaphysis
Prognosis: identical to conventional intramedullary osteosarcoma

Intracortical Osteosarcoma

Low-grade Intraosseous Osteosarcoma

N.B.: the relatively benign appearance has resulted in misdiagnosis as a benign entity!
Cx: transformation into high-grade osteosarcoma
Prognosis: similar to parosteal osteosarcoma; 80 90% 5-year survival rate; local recurrence in 10% (due to inadequate resection)
DDx: fibrous dysplasia, nonossifying fibroma, chondrosarcoma, chondromyxoid fibroma

Osteosarcoma of Jaw

Prognosis: 40% 5-year survival rate (lower probability of metastases, lower grade)
DDx: metastatic disease (lung, breast, kidney), multiple myeloma, direct invasion by contiguous tumor from oral cavity, Ewing sarcoma, primary lymphoma of bone, chondrosarcoma, fibrosarcoma, acute osteomyelitis, amelo-blastoma, Langerhans cell histiocytosis, giant cell reparative granuloma, brown tumor of HPT

P.143

Osteosarcomatosis

Prognosis: uniformly poor with mean survival of 12 (range, 6 37) months
DDx: heavy metal poisoning, sclerosing osteitis, progressive diaphyseal dysplasia, melorheostosis, osteopoikilosis, bone infarction, osteopetrosis

Parosteal Osteosarcoma

Frequency: 4% of all osteosarcomas; 65% of all juxtacortical osteosarcomas
Origin: outer layer of periosteum; slowly growing lesion with fulminating course if tumor reaches medullary canal
Histo: low-grade lesion with higher-grade regions (22 64%), invasion of medullary canal (8 59%); fibrous stroma + extensive osteoid with small foci of cartilage
Age: peak age 38 years (range of 12 58 years); 50% > age 30 (for central osteosarcoma 75% < age 30); M:F = 2:3
Location: posterior aspect of distal femur (50 65%), either end of tibia, proximal humerus, fibula, rare in other long bones
Site: metaphysis (80 90%)
Prognosis: 80 90% 5- and 10-year survival rates (best prognosis of all osteosarcomas)
DDx: osteochondroma, myositis ossificans, juxtacortical hematoma, extraosseous osteosarcoma

Periosteal Osteosarcoma

Origin: deep layer of periosteum
Histo: intermediate-grade lesion; highly chondroblastic lesion with smaller areas of osteoid formation
Age: average 20 years (range of 13 70 years); M:F = 1.7:1
Location: tibia (40%), femur (38%), ulna and humerus (5 10%)
Site: anteromedial diaphysis of proximal tibia + middle / distal femur; limited to periphery of cortex with normal endosteal margin + medullary canal (resembles parosteal sarcoma)

Secondary Osteosarcoma

Prognosis: <5% 5-year survival rate

Small-cell Osteosarcoma

Age: similar to conventional osteosarcoma; M:F = 1:1
Histo: small round blue cells (similar to Ewing sarcoma) lacking cellular uniformity and consistently producing fine reticular osteoid
Location: distal femur
Site: metaphysis with frequent extension into epiphysis; diaphysis (in 15%)
Prognosis: extremely poor

Telangiectatic Osteosarcoma

DDx: aneurysmal bone cyst (no enhancing rim of viable tumor along lesion periphery)

Oxalosis

Cx: pathologic fractures

Pachydermoperiostosis

Prognosis: self-limiting = progression ceases after several years
DDx: hypertrophic pulmonary osteoarthropathy, thyroid acropachy

Paget Disease

P.145

Rx: calcitonin, biphosphonates, mithramycin
DDx: osteosclerotic metastasis, osteolytic metastasis, Hodgkin disease, vertebral hemangioma

Paraosteoarthropathy

Cx: ankylosis in 5%
Rx: 1000 2000 rad within 4 days following surgical removal

Phenylketonuria

DDx: homocystinuria

Phosphorus Poisoning

Pierre Robin Syndrome

May be associated with: CHD, defects of eye and ear, hydrocephalus, microcephaly
Cx: airway obstruction (relatively large tongue), aspiration

Pigmented Villonodular Synovitis

Rx: synovectomy (50% recurrence rate), arthrodesis, arthroplasty, radiation
DDx: (1) Degenerative / traumatic arthritis
  (2) Synovial sarcoma (solitary calcified mass outside joint)
  (3) Sclerosing hemangioma
  (4) Benign xanthoma
  (5) Xanthogranuloma

Intraarticular Localized Nodular Synovitis

Tenosynovial Giant Cell Tumor

Poland Syndrome

May be associated with: aplasia of mamilla / breast

Poliomyelitis

Popliteal Cyst

Progeria

Prognosis: most patients die in their 30s / 40s from complications of arteriosclerosis (myocardial infarction, stroke) or neoplasm (sarcoma, meningioma, thyroid carcinoma)
DDx: Cockayne syndrome (mental retardation, retinal atrophy, deafness, family history)

Pseudoachondroplasia

Pseudofractures

Pseudohypoparathyroidism

Pseudopseudohypoparathyroidism

Pseudoxanthoma Elasticum

Cx: GI tract hemorrhage

Psoriatic Arthritis

DDx: (1) Reiter syndrome (affects only lower extremity)
  (2) Ankylosing spondylitis
  (3) Rheumatoid arthritis (bilaterally symmetric well-defined erosions, juxtaarticular osteoporosis)

Pyknodysostosis

DDx: (1) Osteopetrosis (no dwarfism, no mandibular / skull abnormality, no phalangeal hypoplasia, no transverse metaphyseal bands, anemia, Erlenmeyer flask deformity; bone-within-bone appearance)
  (2) Cleidocranial dysostosis (no dense bones / terminal phalangeal hypoplasia, short stature)

Radiation Injury to Bone

Pathogenesis: vascular compromise with obliterative endarteritis + periarteritis followed by damage to osteoblasts + osteoclasts with decreased matrix production (growing bone + periosteal new bone most sensitive)

Reflex Sympathetic Dystrophy

Rx: sympathetic block, - / -adrenergic blocking agents, nonsteroidal antiinflammatory drugs, radiation therapy, hypnosis, acupuncture, acupressure, transcutaneous nerve stimulation, physiotherapy, calcitonin, corticosteroids, early mobilization

Reiter Syndrome

Cx: gastric ulcer + hemorrhage; aortic incompetence; heart block; amyloidosis

Relapsing Polychondritis

Rx: corticosteroids, immunosuppression
Prognosis: 74% 5-year survival rate; 55% 10-year survival rate; median survival time of 11 years; airway complications account for >50% of deaths

P.152

Renal osteodystrophy

Rx: 1. Decrease of phosphorus absorption in bowel (in hyperphosphatemia)
  2. Vitamin D3 administration (if vitamin D resistance predominates)
  3. Parathyroidectomy for 3 HPT (= autonomous HPT)

Dialysis-related Disorders

Congenital Renal Osteodystrophy

Vitamin D Resistant Rickets

Rx: phosphate infusion + large doses of vitamin D
DDx: vitamin-D deficient and dependent rickets (absence of muscle weakness + seizures + tetany)

Fanconi Syndrome

Prognosis: functional renal impairment likely when bone changes occur
Rx: large doses of vitamin D + alkalinization

Renal Tubular Acidosis

Rheumatoid arthritis

Cystic Rheumatoid Arthritis

DDx: gout (presence of urate crystals), pigmented villonodular synovitis (monoarticular)

Juvenile Rheumatoid Arthritis

Rickets

Cx: stress fracture, bowing deformity

Causes of Rickets

Classification of Rickets

Rotator Cuff Lesions

Subacromial Pain Syndrome

Impingement Syndrome

P.158

Cx: (1) partial / complete tear (may be precipitated by acute traumatic event on preexisting degenerative changes; common cause of rotator cuff tears)
  (2) cuff tendinitis / degenerative tendinosis
Dx: Lidocaine impingement test (= subacromial lidocaine injection relieves pain)
Rx: acromioplasty (= removal of a portion of the acromion), removal of subacromial osteophytes, removal / lysis / d bridement of coracoacromial ligament, resection of distal clavicle, removal of acromioclavicular joint osteophytes

Glenohumeral Instability

Rotator Cuff Tear

False negative: longitudinal tear, partial tear
False positive: intraarticular biceps tendon, soft-tissue calcification, small scar / fibrous tissue

Subacromial-Subdeltoid Bursitis

Supraspinatus Tendinopathy / Tendinosis

Cx: main risk factor for subsequent rotator cuff tear (not impingement)
DDx: supraspinatus tear (tendon has fluid intensity

Rubella

Prognosis: osseous manifestations disappear in 1 3 months; severe congenital defects from infection during first trimester
DDx: (1) CMV
  (2) Congenital syphilis (diaphysitis + epiphysitis)
  (3) Toxoplasmosis

Rubinstein-Taybi Syndrome

Cx in infancy: obstipation, feeding problems, recurrent upper respiratory infection

Sapho Syndrome

Prognosis: chronic course with unpredictable exacerbations + remissions
Rx: nonsteroidal antiinflammatory drugs, corticosteroids, analgesics, cyclosporine
DDx: infectious osteomyelitis / spondylitis, osteosarcoma, Ewing sarcoma, metastasis, Paget disease, aseptic necrosis of clavicle

Sarcoidosis

Scurvy

Infantile Scurvy

Age: 6 9 months (maternal vitamin C protects for first 6 months)
Predisposed: feeding with pasteurized / boiled milk
Pathogenesis: abnormal collagen formation
DDx: TORCH infections, leukemia, neuroblastoma

Adult Scurvy

Incidence: rare

P.161

Septic Arthritis

N.B.: MEDICAL EMERGENCY = immediate treatment necessary to prevent permanent joint damage!

Organism:

Pathophysiology:

Mode of infection:

Age: most prevalent in the young
Location: lower extremity (75%) with hip + knee in 90%

ACUTE SIGNS:

US:

NUC:

MR:

SUBACUTE SIGNS after 8 10 days:

Dx: (1) prompt arthrocentesis:

    turbid / frankly purulent synovial fluid:

    fluid WBC >20,000/mm3 with predominance of PMNs:

    positive result of Gram stain

(2) blood culture
Cx: (1) bone growth disturbance (lengthening, shortening, angulation)

(2) chronic degenerative arthritis

(3) ankylosis

(4) osteonecrosis = avascular necrosis

Shin Splints

Short Rib Polydactyly Syndrome

Sickle cell disease

Functional Asplenia

Autosplenectomy

Acute Splenic Sequestration Crisis

Sickle Cell Trait

SC Disease

Sickle-Thal Disease

Sinding-Larsen-Johansson Disease

Smallpox

Soft-Tissue Chondroma

Soft-Tissue Osteoma

Solitary Bone Cyst

Solitary Plasmacytoma of Bone

Spondyloepiphyseal Dysplasia

Spondyloepiphyseal Dysplasia Congenita

Spondyloepiphyseal Dysplasia Tarda

Sprengel Deformity

Subungual Exostosis

Superficial Fibromatoses

Infantile Digital Fibromatosis

Juvenile Aponeurotic Fibroma

Palmar Fibromatosis

Plantar Fibromatosis

Synovial Osteochondromatosis

= SYNOVIAL CHONDROMATOSIS = JOINT CHONDROMA

Primary Synovial Osteochondromatosis

Secondary Synovial Osteochondromatosis

Synovioma

Syphilis of Bone

Congenital Syphilis

Acquired Syphilis

Tarsal Coalition

Tarsal tunnel syndrome

Thalassemia Syndromes

Thalassemia Major

Thalassemia Intermedia

Prognosis: longer life expectancy

Thalassemia Minor

Thanatophoric Dysplasia

Thrombocytopenia-Absent Radius Syndrome

Thyroid Acropachy

Onset: after >18 months following surgical / radioactive ablation of thyroid gland for hyperthyroidism (does not occur with antithyroid medication)
Incidence: 0.5 1% of patients with thyrotoxicosis
DDx: (1) Pulmonary osteoarthropathy (painful)

(2) Pachydermoperiostosis

(3) Fluorosis (ligamentous calcifications)

Transient Regional Osteoporosis

= TRANSIENT BONE MARROW EDEMA

Cause: unknown;? overactivity of sympathetic nervous system + local hyperemia similar to reflex sympathetic dystrophy syndrome, trauma, synovitis, transient ischemia

Regional Migratory Osteoporosis

Partial Transient Osteoporosis

Transient Osteoporosis of Hip

Transient Synovitis of Hip

Treacher-Collins Syndrome

Trisomy D Syndrome

Trisomy E Syndrome

Tuberculosis of Bone

Incidence: 1 3 5% of tuberculous patients, 30% in patients with extrapulmonary tuberculosis
Age: any, rare in 1st year of life, M:F = 1:1

Tuberculous Arthritis

Tuberculous Osteomyelitis

Incidence: 16% of skeletal tuberculosis
Age: children <5 years (0.5 14%), rare in adults

Tuberculous Spondylitis

Tuberculous Spondylitis without Diskitis

Tumoral Calcinosis

Turner Syndrome

P.175

Bonnevie-Ullrich Syndrome

Turret Exostosis

Cause: trauma with formation of subperiosteal hematoma

Ulnar Collateral Ligament Tear

Cause: chronic overuse in throwing / other overhead motion (eg, tennis serving) generating increased valgus stress

Van Buchem Disease

Williams Syndrome

Wilson Disease

Related

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