Articular malalignment between the scaphoid, lunate, and radius leads to abnormal force loading and the subsequent development of progressive arthritic changes that comprise Scapholunate Advanced Collapse (SLAC) wrist. The purpose of this study is to evaluate the clinical outcomes and complications associated with Lunocapitate Arthrodesis (LCA) for the treatment of SLAC wrist.
We retrospectively identified 56 patients (60 cases) between September 2010 and February 2020 with SLAC wrist changes treated with LCA. Of the 60 cases undergoing LCA, single-screw fixation was utilized in 46 cases, two-screw fixation in 9 cases, and staple fixation in 5 cases respectively. Objective outcomes were derived from union rate, rate of fusion, return to work time, active range of motion, and grip and pinch strength recovery. Subjective outcomes were determined by patient reported Disabilities of the Arm, Shoulder, and Hand (DASH) scores.
We are reporting on 60 cases, 46 male, 14 female, mean age 57 years [range: 31-85] with SLAC wrist who underwent LCA. Our cohort reported a 93% union rate and an 84-day mean rate of fusion. Mean return to work time was 129 days. Final active wrist range of motion was 36° for dorsiflexion, 33° for volarflexion, 16° for radial deviation, 16° for ulnar deviation, 82° for pronation, and 83° for supination (Mean: 396 days). Final grip and pinch strengths recovered were 77% for gross grip, 83% for lateral pinch, and 76% for precision pinch (Mean: 359 days) compared to the contralateral side. The mean preoperative DASH score was 71 compared to the mean postoperative DASH score of 37 (p<0.01). Four non-unions were observed. Two patients went on to have screw removal and one patient went on to have staple removal. Three patients went on to have wrist fusion for continued pain.
In our study we found LCA to be an effective salvage procedure for SLAC wrist. LCA is a less taxing procedure, requires shorter operating time, and produces comparable range of motion, grips strength recovery, and post-operative DASH scores to Four Corner Arthrodesis. Furthermore, the viability of LCA via single-screw fixation may serve to reduce hardware-related operative costs without adversely affecting union rates.