Does ulnar variance relate with TFCC lesions?

This study aims to investigate triangular fibrocartilage complex (TFCC) alterations and accompanying ligamentous pathologies in cases with positive (PUV) and negative ulnar variance (NUV) using MRI, and to compare findings with a control group presenting with ulnar-sided wrist pain but no trauma history. A total of 124 patients were retrospectively evaluated: groups with radiographically confirmed PUV or NUV and a control group with ulnar-sided wrist pain but no trauma history. MRI examinations of the wrist were assessed by two musculoskeletal radiologists. Evaluated parameters included TFCC morphology and integrity, disc thickness and angle, presence and location of tears, integrity of associated ligamentous structures, degenerative findings in ulnar carpal bones, and distal radioulnar joint changes. TFCC tears were observed in 91% of PUV cases, 63% of NUV cases, and 40% of the control group. Central disc perforation rates were 40% in PUV, 10% in NUV, and 10% in controls (P < 0.001). Volar radioulnar ligament (VRUL) and dorsal radioulnar ligament (DRUL) tears were significantly more common in PUV cases (VRUL: 26%, DRUL: 44%) compared to NUV (VRUL: 5%, DRUL: 29%) and controls (VRUL: 0%, DRUL: 7%). Ulnar-sided attachment tears were more frequent in NUV, though not statistically significant (P = 0.062). Ulnocarpal chondromalacia (Palmer 2B) was present in 16% of PUV cases, and degenerative arthritis in ulnolunate and ulnotriquetral joints (Palmer 2E) in 42%, compared to only 5% in NUV and controls (P < 0.001). Ulnotriquetral ligament tears were significantly higher in PUV and frequently accompanied VRUL tears (P = 0.007). Chronic ECU tendon tears were more common in both PUV and NUV groups versus controls (P = 0.002). Multiple compartment TFCC tears are frequently observed in PUV and NUV cases. PUV is significantly associated with disc thinning, central perforation, degeneration, and ulnocarpal joint changes. VRUL and DRUL tears, which are not part of the traditional Palmer classification, are notably common in PUV. Conversely, ulnar attachment tears are more frequently noted in NUV cases.