Wrist is not a single joint. For the purpose of Arthropathies, the wrist can be divided into following compartments:
1. Inferior radioulnar joint
2. Radiocarpal joint
3. Midcarpal joint
4. Pisiform-triquetral joint
5. Carpometacarpal joint
6. 1st CMCJ
RA:
Symmetrical
Initial coimpratments: radiocarpal, radioulnar, pisiform-triquetral
Eventually pancompartmental
Major damage occurs in distal ulna
JCA:
Midcarpal and common carpometacarpal compartments are predominalty involved with distal carpal migration
Eventual fusion of carpal bones and base of 2-5 metacarpals
relative sparing of the 1st CMCJ and radiocarpal joint
OA and erosive OA:
1st CMCJ with radial subluxation and trepizioscaphoid joints
CPPD:
Mimics OA
Radiocarpal joint is predominantly involved with narrowing of the joint space
Also midcarpal
Check lunotriquetral joint for chondrocalcinosis. This is more sensitive than TFCC for chondrocalcinosis
Radial erosions
Decrease in lunate-capitate space
Increase in scapholunate space
Destruction of trapezio-scaphoid joint
Chondrocalcinosis
Gout:
Predominant involvement of common carpometacarpal joints with erosions at the bases of metacarpals
CMCj may also be involved
Septic arthritis:
Never forget this in the differentials
Diffuse pancompartmental
Scleroderma:
Arthropathy in 1st CMCj with subluxation and calcification
SLAC:
Collapse of scapholunate space
References:
Resnick et al, Bone and joint imaging, 3rd edition, Elsevier Saunders publications
