TFCC Tear MRI Signs: Ulnar Wrist Pain, X-ray Clues, and Palmer Types

Palmer traumatic TFCC tears are classified by location: 1A central, 1B ulnar, 1C distal, and 1D radial. Degenerative lesions are grouped separately as 2A-2E by progressive severity.

Ulnar variance describes the length difference between the distal ulna and radius. Positive ulnar variance concentrates load through the TFCC, accelerating degenerative Type 2 changes and ulnar impaction syndrome with lunate and triquetrum chondromalacia. Negative variance reduces TFCC load but is associated with Kienbock's disease. Ulnar shortening osteotomy is a primary surgical strategy when positive variance accompanies degenerative TFCC tears. If joint-space narrowing is the dominant finding, compare wrist arthritis; if there is post-traumatic distal radial tilt or shortening, compare distal radius fracture.

The central disc normally shows uniformly low signal on all sequences. Pathological tears appear as focal high T2 signal or complete discontinuity traversing the disc. Foveal detachment (Type 1B) manifests as fluid between the ulnar attachment and the fovea with distal radioulnar joint instability. Pseudo-tears from magic angle artifact can mimic radial-sided tears on standard sequences and should be confirmed on perpendicular planes. MR arthrography with intra-articular gadolinium increases sensitivity for complete tears by demonstrating contrast extravasation.