METABOLIC (CRYSTAL DEPOSITION) ARTHROPATHY
CALCIUM PYROPHOSPHATE DEPOSITION DX (CPPD) peripheral jt, deposits crystal in hyaline / fibrocartilage
Chondrocalcinosis
PyroPhosphate arthropathy
Ddx from DJD *5 Features
Unusual distribution (e.g. shoulder)
Unusual intraarticular distribution (e.g. lateral tibiofemoral joint, radiocarpal joint)
Prominent subchondral cysts
Severe subchondral bone changes (e.g. fragmentation, collapse, loose bodies)
Variable osteophyte formation
Knee - menisci, patellafemoral (medial, lateral, isolated changes)
Wrist
Calcification in triangular fibrocartilage complex (TFCC)
Radiocarpal joint
Large cysts
“Terry Thomas sign”
Scapholunate advanced collapse (SLAC) wrist
HYDROXYAPATITE DEPOSITION Dx (HADD)
Calcific Tendonitis Tendon Ca2+ near insertion
Round, oval, sharp margins
GOUT Hyperuricaemia, renal calculi, 1st MTP, Tophi in synovium, cartilage, subchondral bone
Tophi eccentric, periarticular
Bone erosion, “overhanging margin”
Joint space preserved until late
Bone density remains normal
Hand
Erosions, soft tissue swelling, misalignments
Wrist “spotty carpals”
Bone density is normal
SARCOID affects multiple organ systems, non-caseating granulomas, hepatosplenomegaly, chest x-ray
Middle and distal phalanges m/c (granulomas form in marrow space or paraosseous tissue)
Diffuse-- “lace-like” trabecular pattern
Well circumscribed-- cystic lucencies
Chest: lymphadenopathy (potato nodes) and fibrosis
OCHRONOSIS
Spine
Peripheral Joints
Loss of disc height and disc calcification
Minimal osteophytosis
Multiple vacuum phenomena
Eventual fusion
early severe degenerative changes
chondrocalcinosis
PIGMENTED VILLONODULAR SYNOVITIS PVNS hips, peripheral joints
Marginal erosions
Pressure erosions
Joint effusion
Soft tissue masses
Apple Core Deformity - circumferential erosion of femoral neck
IDIOPATHIC TUMORAL CALCINOSIS