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