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75 Cards in this Set
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Synovial osteochondromatosis
Case findings: Multiple calcifications in within the region of the synovium Erosion of the femoral head Formation of multiple cartilaginous nodules within the synovium Well defined bony erosions may be seen Primary: synovial metaplasia Secondary: MC due to osteoarthritis MC finding is multiple rounded calcified or ossified loose bodies in the synovium Appear as rounded densities with central lucencies Complication: Malignant transformation to synovial chondrosarcoma |
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Unicameral bone cyst
Case findings: Radiolucent lesion with sclerotic margins Mild cortical thinning Mild osseous expansion of the body of the calcaneus DDX: Intrasosseous lipoma: may see central calcification Pseudotumor: thinning of the trabeculae |
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Fibromatosis
Case findings: XR: Areas of lucency, cortical thinning, and bony remodeling within adjoining portions of the distal right radius and ulna Periosteal elevation along volar aspect of both bones MRI: Soft tissue mass centered in the interosseous membrane and flexor compartment of distal right forearm Mass is predominantly dark on both T1 and T2 Enhances heterogeneously DDX: Fibromatosis Fibrosarcoma MC ST malignancy in neonate and young infant Rhabdomyosarcoma Older children and commonly arise from muscles of the extremities Signal characteristics similar to muscle Not usually low signal on T1/T2 Synovial cell sarcoma MC in 3-5th decade Similar imaging features as fibromatosis Benign lesion that never metastasizes but can be locally aggressive Classification: Superficial: small and slow growing Deep: generally more aggressive MC low T1 and T2 (fibrous nature) Enhancement is variable, ranges from none to diffuse |
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Scleroderma (progressive system sclerosis)
Case findings: Resorption of the distal phalanges Classic: ST calcification Atrophy of the finger tips (tapering) Autoamputation of the terminal tufts (pencil-in-cup deformity) Intercarpal joint space narrowing DDX acro-osteolysis (PINCHFO) Psoriasis, sarcoidosis Injuries: frostbite, thermal injury, post-traumatic Neuropathic: DM, leprosy, chronic insensitivity to pain, Lesch-Nyan syndrome CVD: scleroderma Hyperparathyroidism Familial/congenital: Hajdu-Cheney Occupational: polyvinyl chloride exposure |
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Melorheostosis
Case findings: Multiple areas of increased bone density Marked thickening of the lateral femoral cortex, which has a somewhat undulating medial margin Dripping wax appearance to the margins of the hyperostotic bone in the 2nd - 4th phalanges Frequently distributed along a single sclerotome Bone scan: appearance similar to Paget’s Often crosses joints and may result in flexion contractures |
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Pellegrini-Stieda
Calcification or ossification of the MCL at its insertion on the medial femoral condyle |
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Hyperparathyroidism
Case findings: Multiple lytic and somewhat expansile lesions with well-defined borders Subperiosteal resorption is present along the radial aspect of the proximal and mid phalanges Brown tumors (osteoclastomas): Multiple well margined lytic lesions MC eccentric and cortical in location DDX: enchondroma |
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Erosive inflammatory OA
MC post-menopausal women STS, bone proliferation with central erosions sea-gull deformity May see ankylosis of IP joint (not seen in non-inflammatory OA) DDX of single joint involvement: Septic arthropathy Psoriasis Erosive osteoarthritis Adult Still’s disease Cronkhite-Canada syndrome Inflammatory polyposis associated with erosive OA |
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Osteochondroma
Case findings: Exophytic expansile lesion in spinous process Vertebral osteochondroma is MC in posterior osseous elements Direct continuity of cortex and marrow cavity Tip of the osteochondroma is covered by hyaline cartilage cap |
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Osteoblastoma
MC located in the posterior element of the vertebral body DDX: Aneurysmal bone cyst Osteoid osteoma Osteoblastoma |
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Ankylosing spondylitis
Case findings: Ankylosis of SI joints Syndesmophyte: ossification of annulus fibrosis Ossification of interspinous ligaments MC seronegative spondyloarthropathy Males 15-35 years-old Extra-articular manifestations: Iritis, aortic insufficiency, UL interstitial lung disease Sacroiliitis: involves ligamentous and synovial portion of the SI joint Bamboo spine: from continuous syndesmophytes Squaring of vertebral bodies |
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Osteopetrosis (marble bone disease, Albers-Schonberg)
Types: congenital AR lethal, tarda AD benign Symmetrical generalized dense bones with lack of cortical and medullary differentiation Bone-in-bone appearance in spine and long bones Sandwich vertebra sign: increased density at end plates Diffuse vertebral body sclerosis Increased density at skull base and calvaria DDX: Engelmann’s disease: affects only diaphysis of tubular bone (in contrast, osteopetrosis affects the entire bone) |
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CPPD deposition disease
CPPD (calcium pyrophosphate dihydrate) deposition leads to Distinctive gout-like pattern of arthritis (pseudogout) Structural joint damage (pyrophosphate arthropathy) Calcification of articular cartilage (knee, hip, shoulder, TFCC, symphysis) Patello-femoral compartment involvement Pseudogout arthropathy (similar to OA): Medial joint space narrowing Subchondral sclerosis Osteophyte formation Chondrocalcinosis Chondrocalcinosis: Calcification of hyaline (articular) cartilage or fibrocartilage (menisci) DDX (“HOGWASH”) of chondrocalcinosis: Hemochromatosis Ochronosis Gout Wilson’s Acromegaly MC pseudogout (CPPD deposition) Hyperparathyroidism |
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Aneurysmal bone cyst
Expansile lesion containing thin-walled, blood-filled cystic cavities MC long tubular bones and spine DDX lytic lesion in spinous process: Osteoblastoma Aneurysmal bone cyst Osteoid osteoma |
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Chondrosarcoma
Case findings: XR: mixed lytic and sclerotic lesion within the right frontal bone with relatively well-defined sclerotic margins CT: thickening of the outer table, presence of calcified matrix May occur as: Primary bone tumor or Develop from a pre-existing lesion (e.g., enchondroma) Pain is a distinguishing feature between enchondroma and chondrosarcoma |
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Neurofibroma
Case findings: T1: homogeneously isointense with muscle ovoid mass along the expected course of the femoral neurovascular structures T2: target appearance with a hyperintense rim and central area of decreased SI Target appearance (on T2): unique to NF Dense collagen and fibrous tissue centrally and myxoid material at the periphery |
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Bone infarct
Case findings: Patchy areas of lucency and sclerosis Bone collapse at articular surfaces Osteonecrosis: encompasses both AVN: occurs at articular surface (e.g., femoral epiphysis) Bone infarct: occurs away from articular surface (e.g., diaphysis of long bones) |
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Discoid meniscus
Sagittal: continuous meniscal signal is seen on three or more sagittal images that are 5 mm thick Coronal: meniscal tissue extends closer to the notch than a normal meniscus and the height of the discoid meniscus may be 2 mm or greater than the opposite meniscus MC affects lateral meniscus |
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GCT of tendon sheath (extra-articular PVNS)
MC slow growing and painless Bone involvement is rare and no calcification is seen May have pressure erosions DDX: Chronic hemarthrosis Malignant fibrous histiocytoma Desmoid tumor |
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Pigmented villonodular synovitis (PVNS)
Proliferative disorder affecting synovium of joints, bursae, and tendons Dense hemorrhagic effusion Hemosiderin deposition Well-defined erosions Nodular synovial masses in a juxta-articular distribution (low T1 and variable T2) NOT seen: osteophytic response |
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Dorsiflexion intercalated carpal instability (DISI)
Case findings: Gap of 4 mm between scaphoid and lunate Lateral XR: dorsal flexion of the lunate |
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Essex-Lopresti fracture
Comminuted and displaced fracture of the radial head AND Subluxation or dislocation of the DRUJ Due to longitudinal compression force Monteggia fracture Fracture of the ulna and dislocation of the radial head Monteggia fracture MC than Galeazzi fracture |
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Malgaigne fracture
Case findings: Fracture of right sacral ala, and right pubic rami Unstable, vertical shear fracture Breaks occur at two locations in the pelvic ring (anterior and posterior aspects) Examples: Vertical fracture of both pubic rami AND a fracture of the ilium or sacrum or a dislocation of the SI joint Dislocation of the symphysis with either dislocation of the SI joint or fracture of the sacrum or ilium |
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Segond fracture
Vertical avulsion fracture of proximal lateral tibia at insertion of the lateral capsular ligament Occurs with knee in flexion as a result of internal rotation of tibia Differentiate from avulsion proximal fibula (insertion site of biceps femoris and lateral collateral ligament) Segond fracture associated with: ACL tear, meniscal tear O’Donahue’s triad: ACL tear, MCL injury, medial meniscus injury |
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Chondromalacia patella
Case findings: CT arthrogram (utilizing air as the contrast material): demonstrates superficial irregularity of patellar cartilage Loss of cartilage over one or more portions of the patella MC medial facet of the patella Odd facet (medial aspect of the medial facet) is the MC affected by chondromalacia |
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Dorsal defect of the patella
Case findings: Round lytic lesion with sclerotic rim on articular surface of the patella, upper outer quadrant Variation in normal ossification of the bone Alternatively, may be related to traction occurring in the insertion site of the vastus lateralis muscle Appears as radiolucent area in superolateral aspect of patella DDX: Chondroblastoma Osteochondritis Gout |
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Maisonneuve fracture
Components: Fracture of the proximal third of fibula Rupture of the distal tibiofibular syndesmosis Associated with: Fracture of the tibia Rupture of the deltoid ligament (medial ankle) |
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Gout
Case findings: XR: Focal prominence of ST overlying 1st tarsometatarsal joint Erosive deformity along medial margin of 1st tarsometatarsal joint MRI: Destruction of medial dorsal aspect of medial cuneiform bone with adjacent ST mass Central necrosis and peripheral gadolinium enhancement DDX: Gout Focal pigmented villonodular synovitis Soft tissue sarcoma Amyloid Giant cell tumor of tendon sheath Well defined erosions with sclerotic borders or overhanging edges Soft tissue nodules may calcify in presence of renal failure Random distribution in hands without marked osteoporosis Affects 1st MTP joint 40% with gout have concomitant CPPD (look for chondrocalcinosis) |
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Spontaneous osteonecrosis about the knee (SONK)
Case findings: Coronal fat-suppressed proton-density and sagittal inversion recovery images Irregularity of the subchondral bone and subjacent bone marrow edema in medial femoral condyle Tear of the medial meniscus Also called Ahlback’s disease Idiopathic disorder characterized by osteonecrosis and distinct from osteochondritis dissecans Affects the weight-bearing surfaces of the joint (medial femoral condyle) |
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Cyclops lesion
Case findings: Sagittal T2: Status post ACL reconstruction Nodular focus of low signal intensity at the posterior aspect of Hoffa's infrapatellar fat pad Localized form of anterior arthrofibrosis Complication of reconstruction of the ACL Located anterior to the graft and may be the result of debris from drilling in preparation of the tibial tunnel, or it may relate to graft impingement from injured ligamentous fibers MR low signal intensity, consistent with fibrous tissue DDX lesions in Hoffa’s fat pad: Cyclops lesion Hoffa’s disease: traumatic and inflammatory changes occurring in the infrapatellar fat pad in young athletes leads to fibrosis Synovitis Intra-articular loose body Synovial osteochondromatosis Solitary chondroma |
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Acromegaly
Case findings: ST prominence, tuft size is increased and spadelike Heel pad thickening (> 23 mm may suggest acromegaly) Enlargement of destruction of sella turcica Secondary to pituitary adenoma Onset of acromegaly is in the 3rd - 5th decade Gigantism: manifested by an increase in stature, when the syndrome occurs before epiphyseal fusion |
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Lipoma arborescens
Case findings: Sagittal T1: hypertrophic synovial villi distended with fat and a large joint effusion Sagittal T2: frondlike mass and large joint effusion in the suprapatellar recess Intra-articular fatty tumour of unknown cause MC in knee May arise de novo or develop in DJD, RA, or trauma Focal deposits of fat are observed beneath a swollen synovial membrane |
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Adamantinoma
Case findings: Expansile osteolytic lesion with patchy sclerosis in the tibia MC localized in the middle third of the tibia or other tubular bone Multilocular, slightly expansile osteolytic lesion, sometimes with reactive bone sclerosis and small satellite radiolucent foci DDX: Fibrous dysplasia Osteofibrous dysplasia (ossifying fibroma): cannot differentiate from adamantinoma |
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Pyknodysostosis
DDX of diffuse osteosclerosis and acro-osteolysis: Hyperparathyroidism Pyknodysostosis Skull: Hypoplasia of mandible Widening of cranial sutures AR, short stature, normal mentation Wormian bones Wormian bones Intrasutural bones, MC lambdoid suture DDX (PORKCHOPS) Pyknodysostosis Osteogenesis imperfecta Healing rickets Menke’s kinky hair syndrome: defective intestinal copper absorption Cleidocranial dysostosis Hypothyroidism (cretinism), hypophosphatasia Otopalatodigital syndrome: an osteochondrodysplasia characterized by typical facies, hearing defects, and digits resembling those of a tree frog in both hands and feet Primary acro-osteolysis (Hadju-Cheney) / pachydermoperiostosis (idiopathic, familial hypertrophic osteoarthropathy) Down’s syndrome |
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Osteopetrosis (marble bone disease, Albers-Schonberg)
Types: congenital AR lethal, tarda AD benign Symmetrical generalized dense bones (lack of cortical and medullary differentiation) Bone-in-bone appearance in spine and long bones Sandwich vertebra sign: increased density at vertebral end plates Diffuse vertebral body sclerosis Increased density at skull base and calvaria DDX: Engelmann’s: affects only diaphysis of tubular bone (in contrast, osteopetrosis affects the entire bone) Sandwich vertebra sign: increased density at end plates |
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Chondroblastoma
DDX end of bone lesion (epiphysis, apophysis): Chondroblastoma ABC GCT Infection EG Low-grade chondrosarcoma |
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Glomus tumor
Case findings: Scalloped lytic defect with sclerotic border Benign vascular tumor Clinical triad: sensitivity to cold, localized tenderness, severe intermittent pain DDX tuft cystic lesion: Subungual glomus tumor (enhances) Epithelial inclusion cyst Thorn granuloma (enhances) |
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Tumoral calcinosis
Small calcified nodules progress to large multilobular calcific deposits in periarticular tissues MC on extensor surfaces Single joint involvement |
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Sarcoidosis
Lacelike lytic lesions in short tubular bone |
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Chondrosarcoma
XR: Lucency in left sacrum with an abnormal soft tissue density containing calcified matrix overlying the left sacrum and ilium CT: Large mass surrounding and involving the left posterior ilium and sacrum Cortical destruction of the posterior sacrum and ilium ST tissue component of the mass invades the iliacus and gluteal muscles and contains multiple areas of calcification DDX: Chondrosarcoma Osteosarcoma Chordoma Plasmacytoma XR: lucent lesion with scalloping of the cortex and periosteal reaction CT: define the cortex and visualize calcification of the cartilage matrix MR: presurgical evaluation to visualize the extent of bone and soft tissue involvement |
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TB arthritis
Case findings: XR: lobulated lucency of proximal ulna, demineralization of the distal humerus, and effusion CT: erosions of the radial head, distal humerus and ulna with edema or cellulitis in the subcutaneous tissues posterior to the elbow MR: correlate well with CT and demonstrate joint effusion with abnormal signal and bony destruction of the distal humerus and proximal radius with likely cellulitis in the posterior subcutaneous tissues Chest CT (not shown): demonstrates LUL nodules Uncommon, slowly progressive disease MC monoarticular and involves weight bearing joints Early changes: distention of joint capsule/effusion, soft tissue swelling, joint dislocation Late changes: joint space destruction, erosion, osteopenia |
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Parosteal osteosarcoma
Case findings: XR: Exuberant, aggressive, disorganized periosteal reaction of the distal femur with increased sclerosis of the bone CT: Confirm a large mass with extensive bone formation, portions contiguous with the cortex of the femur MR: Large mass of mixed signal intensity that arises from and nearly encircles the distal femur Greatest bulk of the mass projects posteriorly Bone marrow involvement and cortical breakthrough near the lateral femoral condyle Osteosarcoma: 2nd MC primary malignant bone tumor (after multiple myeloma) May be secondary to: Paget’s disease Fibrous dysplasia 3-50 years after radiation Dedifferentiated chondrosarcoma Types: Parosteal, periosteal Conventional Telangiectatic Radiology: Purely osteolytic (~30% of cases) Purely osteoblastic (~45% of cases) Mixture of both Elevation of the periosteum (Codman triangle) Extension of tumor through the periosteum may result in a sunburst appearance MR: assess extent of intramedullary disease (medullary backgrowth) Bone scan: evaluation for the presence of metastatic or multifocal disease |
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Multiple hereditary exostoses
Case findings: Multiple large, irregular, calcified masses arising from distal femora and proximal tibia and fibula Continuity of the medullary space and cortical surface of the masses into the underlying metaphysis No sclerotic margin, orientation away from the adjacent joints, and the presence of cartilage caps are demonstrated DDX single osteochondroma: Osteoma Periosteal chondroma Juxtacortical myositis ossificans Fibrous dysplasia Chondrosarcoma Parosteal osteosarcoma Soft tissue osteosarcoma |
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Osteosarcoma
AP pelvis: Calcified ST mass associated with the mid portion of the left ischium with mild bony irregularity of the ischium CT pelvis: Pathologic fracture through left acetabulum Osteolytic defect of ischium and ileum at the hip joint Soft tissue mass with calcification medial to acetabulum. MR pelvis: Heterogeneous mass in left acetabulum extending anteroinferiorly into the pubic ramus and posteriorly into the ischium Extensive soft tissue component projecting medially and displacing the obturator internus muscle heterogeneous enhancement of the bone Peripheral enhancement is noted in the soft tissue mass suggesting a central necrotic component MC males, 2nd – 3rd decades DDX: Ewing’s sarcoma Classification by location: Intramedullary or central Intracortical Surface Periosteal Parosteal |
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DDX solitary lucent epiphyseal lesion
Chondroblastoma Giant cell tumor Aneurysmal bone cyst Eosinophilic granuloma Intraosseous ganglion Geode Infection (TB) PVNS (often multiple lucencies, erosions) Pigmented villonodular synovitis Case findings: XR: Sharply marginated cortical lucency in proximal tibia MRI: Synovial proliferation with diffuse hemosiderin deposition (low T1 and T2) within the hypertrophied synovium Bone erosion within the posterior aspect of the tibial plateau, just inferior to the tibial eminence Fluid in the suprapatellar pouch Types: Nodular form: Focal proliferation of synovial tissue within any synovial-lined structure, and MC occurs in tendon sheaths and IP joints of the hands Former variety is often referred to as tendon sheath xanthoma or giant cell tumor of a tendon sheath Diffuse form: Proliferation of synovial tissue in intraarticular synovial cavity of a joint MC monoarticular, MC knee Proliferating synovium causes pressure erosion of adjacent bone MC monoarticular and LACKS periarticular osteopenia DDX: Synovial osteochondromatosis: Synovial proliferation and the formation of cartilaginous or calcified loose bodies in synovial space Non-calcified synovial osteochondromatosis can appear identical to PVNS No hemosiderin deposition Synovial sarcoma: No hemosiderin deposition |
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Osteonecrosis
Case findings: Extensive avascular necrosis involving left femoral head, neck and proximal shaft Reactive left hip joint effusion Right femoral head demonstrates a lesser degree of avascular necrosis than the left femoral head Etiology (GASEPTIC): Gaucher’s Anemia Steroids Ethanol Pancreatitis, pregnancy Trauma Idiopathic (LCP) Caissons, collagen vascular disease |
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Perilunate dislocation
Diagnosis: dorsal perilunate dislocation with scapholunate disruption and no evidence of fracture Case findings: Volar tilt to the lunate Capitate is dorsal to and overlaps the lunate Proximal lunate articular surface remains aligned with the distal radius Associated widening of the scapholunate joint AP view: Carpus is foreshortened with overlap of the proximal and distal rows Triangular shaped lunate indicates tilting of the lunate which could be associated with lunate or perilunate dislocation Lateral view is needed to make the diagnosis Perilunate dislocation Capitate lies dorsal or volar to the lunate bone Proximal articular surface of the lunate remains parallel to distal radius Lunate dislocation Proximal articular margin and central axis of the capitate remain aligned with distal radius Lunate is almost invariably displaced volarly |
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Osteochondritis
Case findings: Widening of the capitellum with decreased mineralization Fragmentation and ST density with the radiocapitellar joint MC children between the ages of 10-15 years little league elbow Little league elbow Medial epicondyle avulsion Delayed or accelerated growth of the medial epicondyle Medial epicondylar apophysitis Delayed closure of the medial epicondylar growth plate Osteochondritis or OCD of the capitellum Deformity of the radial head Olecranon apophysitis Panner’s disease Involves capitellum of distal humerus MC boys, 5-10 years old Separated from osteochondritis by age, mechanism and no loose body formation Full return of function whereas osteochondritis often leads to post-traumatic arthritis |
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Giant cell tumor
Osteolytic eccentric, epiphyseal extension from metaphyseal origin Intermediate aggressiveness with poorly defined margins and no rim of sclerosis MC about knee, 50% recurrence After irradiation: chance of malignant transformation into osteosarcoma or fibrosarcoma DDX: Giant cell tumor Aneurysmal bone cyst Chondroblastoma LCH Infection Greater trochanter: apophysis, an epiphyseal equivalent |
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Osteopoikilosis
Case findings: Multiple, ill-defined, sclerotic lesions throughout the pelvis with the appearance of multiple bone islands Type of osteosclerotic dysplasia Features: Multiple well-defined, rounded, small, homogenous sclerotic foci Symmetric distribution, predilection for epiphyseal and metaphyseal segments of tubular bone Appear as multiple bone islands DDX multiple sclerotic lesions: Multiple bone islands Osteopoikilosis Osteoblastic metastases Mastocytosis Tuberous sclerosis Mastocytosis Proliferation of fibroblasts and granulomatous tissue in the marrow replacing normal marrow Osteopenia, expansion and ballooning of the medullary cavity, thin cortices Remaining trabecula is thickened Sclerosis takes place with bone repair Small bowel: Wall thickening and barium segmentation Small nodular filling defects in a segmental pattern |
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Fibrolipomatous hamartoma (neural fibrolipoma)
Case findings: Axial proton-density MR image of the wrist: heterogenous mass within the carpal tunnel Mass contains fat, displaces the flexor tendons and causes bowing of the flexor retinaculum Tumor of fatty and fibrous tissue MC involves median nerve in the carpal tunnel, LC tibial nerve Associated with macrodystrophia lipomatosa Gradual infiltration of nerves by fibrofatty tissue (MC median nerve) |
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Fibrous dysplasia
Case findings: XR: large expansile lesion of 12th posterior rib DDX: Fibrous dysplasia Plasmacytoma Metastatic disease Chondrosarcoma Radiolucent expansile medullary lesion (but may replace both cancellous and cortical bone) Ground glass: due to dysplastic microtrabeculae Well-defined sclerotic margins, endosteal scalloping Either monostotic (80%) or polyostotic McCune-Albright syndrome: Polyostotic fibrous dysplasia Cafe au lait spots Precocious puberty |
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Dermatomyositis
Linear and confluent calcifications in soft tissues (at pressure points in the extremities, axillae, hands and inguinal regions) Lacy, reticular subcutaneous calcium deposit encasing the trunk Fibrosis leads to contractures and deformities of the trunk |
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Hemophilic arthropathy
Hemorrhage produces synovitis (pannus formation) Features: Overgrowth of epiphysis Widening of intercondylar notch (knee) Hemosiderin deposition Joint effusion DDX: Juvenile RA |
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Lipohemarthrosis
Mixture of fat and blood in a joint cavity following trauma Presence of a fat-fluid level is nearly diagnostic of a fracture, even when that fracture is radiographically occult Posterior dislocation of the right hip with blood and fat filling the acetabular fossa White arrow indicates fat layering upon blood (black arrow) Lipohemarthrosis of glenohumeral joint: globular focus of fat layering upon a small amount of blood |
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Onchronosis (alkaptonuria)
Spondylitis and arthritis of large joints (knees, shoulders, hips) Deposition in cartilage synovial thickening Spine: Degenerative disc disease Resembles ankylosis spondylitis Disc space calcification Pathognomonic: seen in younger patient Universal disc calcification DJD of root joints (hips and shoulders) LS and Pelvis: Severe osteoporosis Widespread discal calcifications with disc space loss Sclerosis of SI joints bilaterally Ossification in acetabular labra of the hips |
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Tarsal coalition
Diagnosis: subtalar coalition (talocalcaneal) Case findings: Lateral ankle: C sign: C-shaped line formed by medial outline of talar dome and inferior outline of sustentaculum tali CT ankle: Bony bridge between talar dome and sustentaculum tali Types: cartilage, fibrous tissue, osseous MC calcaneonavicular, LC talocalcaneal Diagnosis: calcaneonavicular coalition Anteater nose sign: enlargement of the anterosuperior portion of the calcaneus (arrow) Diagnosis: talocalcaneal coalitition Osseous excrescence or "beak" protruding from anterior talus (arrow) |
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Multiple hereditary exostoses (MHE)
Multiple bilateral and symmetrical osteochondromas MRI may be used to assess cartilaginous cap Development of pain attributable to an exostosis is worrisome from sarcomatous degeneration Complications: Fracture Vascular injury Neurologic compromise Bursa formation Malignant transformation |
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Jaccoud’s arthritis
Case findings: Radial deviation at radiocarpal joint Ulnar deviation at the MCP joints Capsular erosions at several metacarpal heads Deforming nonerosive arthropathy that may appear after repeated attacks of arthritis in patients with rheumatic fever Asymptomatic, reversible joint deformities |
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Osteoarthritis
Features: Joint space narrowing Subchondral sclerosis Marginal osteophyte formation Subchondral cysts Hands Not due to mechanical stress MC involves 1st MCP of thumb, DIP Secondary degenerative arthritis Atypical location: CPPD (knee) Atypical appearance: marked DJD of one hip (RA, AVN) Atypical age Types: Trauma, infection AVN RA, CPPD Hemophilia |
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Gout
Asymmetric, monoarticular MC involves 1st MTP Olecranon bursitis common Tophi rarely calcify Features: Juxta-articular erosions (overhanging edges) No joint space narrowing (JSN a late finding) Soft tissue swelling No osteoporosis |
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Rheumatoid arthritis
Features: Bilaterally symmetrical Proximal joints: MCP, PIP, ulnar styloid Periarticular demineralization May lead to secondary DJD: Marked narrowing of joint space Intact articular cartilage Little or no sclerosis RA foot: 5th MTP early (MC) RA of hips: marked JSN, little sclerosis |
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Systemic lupus erythematosus
Subluxation without erosions DDX: SLE, Jaccoud's arthropathy AVN: intrinsically or secondary to steroids |
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Psoriatic arthritis
Case findings: Hand: Periostitis (arrows) STS of 3rd digit Erosions at margin of DIP joint Fingers: Marginal and central erosions (arrows) Intra-articular ankylosis Flexion contractures at DIP joints MC involves DIP (hands > feet) Acro-osteolysis (pencil-in-cup deformity) Soft tissue swelling (sausage digit) No osteoporosis Asymmetric SI involvement (like IBD, TB) Spine: non-marginal syndesmophytes Case findings: diffuse fusiform soft-tissue swelling of entire 3rd digit Sausage digit: fusiform soft-tissue swelling involving an entire, single digit Psoriatic sacroiliitis Asymmetric SI joint (DDX: IBD, TB) Non-marginal syndesmophytes Ivory phalanx sign Sclerosis of an entire phalanx (MC great toe) Result of bony proliferation as an exaggerated healing response to injury Seen in seronegative spondyloarthropathy (e.g. psoriatic arthritis) |
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Scleroderma
Case findings: Hands: acroosteolysis and flexion contractures Pelvis: extensive soft tissue calcifications MC affects DIP, IP, and surrounding soft tissues areas of the hand Acroosteolysis at distal phlangeal tufts secondary to pressure from surrounding sclerotic soft tissues Soft tissue subcutaneous and periarticular calcifications Soft tissue atrophy and thickening Tendon sheath fibrosis can cause contracture deformities Preferential involvement of 1st CMC Osteolysis of trapezium and 1st metacarpal base 1st metacarpal subluxation Intra-articular calcifications |
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Charcot arthropathy
Features: Fragementation Soft tissue swelling Joint destruction Sclerosis Osteophytosis Joint involvement: Shoulder (syrinx) Hips (tertiary syphilis, diabetes) Feet (diabetes) |
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Multiple bone infarcts from sickle cell disease
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Avascular necrosis
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Pigmented villonodular synovitis (PVNS)
Proliferative disorder affecting synovium of joints, bursae, and tendons Dense hemorrhagic effusion Hemosiderin deposition Well-defined erosions Nodular synovial masses in a juxta-articular distribution (low T1 and variable T2) NOT seen: osteophytic response |
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Acetabular protrusio
Diagnosis: Paget’s Medial wall of acetabulum projects medial to ilioischial line (> 6 mm women, > 3 mm men) Primary protrusio (Otto pelvis): Affects middle-aged women Familial protrusion of the acetabulum, bilateral Secondary: Paget’s disease Rheumatoid arthritis, ankylosing spondylitis, septic arthritis Osteoarthritis, osteomalacia Sickle cell anemia Neoplasm, trauma, irradiation RA, CPPD: Axial migration of femoral head Symmetric loss of joint space OA: Migration of femoral head is superior or medial Consequence of more focal destruction of cartilage Primary acetabular protrusio (Otto pelvis) Idiopathic protrusio acetabuli bilaterally, secondary arthritic changes are seen |
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Chondrocalcinosis
CPPD (calcium pyrophosphate dihydrate) deposition leads to Distinctive gout-like pattern of arthritis (pseudogout) Structural joint damage (pyrophosphate arthropathy) Calcification of articular cartilage (knee, hip, shoulder, TFCC, symphysis) Patello-femoral compartment involvement Pseudogout arthropathy (similar to OA): Medial joint space narrowing Subchondral sclerosis Osteophyte formation Chondrocalcinosis Chondrocalcinosis: Calcification of hyaline (articular) cartilage or fibrocartilage (menisci) DDX (“HOGWASH”) of chondrocalcinosis: Hemochromatosis Ochronosis Gout Wilson’s Acromegaly MC pseudogout (CPPD deposition) Hyperparathyroidism |
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Fibrous dysplasia
Radiolucent expansile medullary lesion (but may replace both cancellous and cortical bone) Ground glass: due to dysplastic microtrabeculae Well-defined sclerotic margins, endosteal scalloping Either monostotic (80%) or polyostotic McCune-Albright syndrome: Polyostotic fibrous dysplasia Cafe au lait spots Precocious puberty |
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Non-ossifying fibroma
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Reiter’s syndrome
Clinical triad: urethritis, arthritis, conjunctivitis Periostitis at tendinous insertions (whiskering) DDX: DISH, AS Osteoporosis DDX: RA |
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Prepatellar bursitis
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Osteochondritis dessicans
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