The present prospective study investigated the influence of the static ulnar variance on the success of arthroscopic debridement of degenerative TFCC lesions.
10 patients with an ulnar positive variance ("Ulna+") and 12 patients with ulnar neutral or ulnar negative variance ("Ulna-/0") were examined preoperatively (U0), as well as at 2 (U2) and 6 (U6) months after arthroscopic debridement of degenerative TFCC lesions and compared with each other. After the U2 investigation due to persistent complaints in 9 of 10 patients with an ulnar positive variance there was a need for further surgery, consisting of ulnar shortening osteotomy (USO). The following parameters were recorded in each case: pain at rest and with load, the summed wrist range of motion - consisting of extension and flexion, radial and ulnar deviation, pronation and supination - compared to the contralateral side, the strength of the affected hand compared to the contralateral side, the Mayo modified wrist score (MMWS), the Krimmer score and the DASH score. Preoperatively there were no significant differences between the 2 cohorts "Ulna+" and "Ulna-/0" except for the characteristic "pain at rest".
At 2 months postoperatively (U2), the results in the cohort "Ulna+" remained at a significantly or tendentially poorer level compared to the cohort "Ulna-/0". The subsequent surgical treatment of the subgroup "Ulna+" with USO led to almost complete approximation of the results at 6 months postoperatively (U6). In addition to this, with time (U6) within each subgroup there were tendential or significant improvements of all characteristics compared to the preoperative situation (U0). At U6 four of 22 patients were -unable to work.
Degenerative lesions of the TFCC can be treated successfully by arthroscopic debridement in cases of ulnar negative and ulnar neutral variance. Patients with ulnar positive variance and persistent complaints after debridement of the TFCC can be treated successfully with a secondary ulnar shortening osteotomy.