Scaphocapitate Fusion in Advanced Kienböck’s Disease
Authors: Collon Sylvie , Berger Anthony , Tham Stephen , McCombe David 
Published: September 2016

Objective: The treatment goal in Kienböck’s disease is to preserve the integrity and allow revascularization of the lunate and preserve wrist motion while relieving patients’ symptoms. In stage 3 Kienböck’s disease, the lunate is often unsalvageable due to comminution and subsequent collapse. Scaphocapitate (SC) fusion aims at decompressing the lunate while restoring carpal height and maintaining wrist motion. Materials and Methods: We retrospectively reviewed patients with a minimal 1-year follow-up who underwent SC fusion in stage 3A and 3B Kienböck’s disease. Eleven patients were reviewed clinically and radiologically. Pain, Disabilities of Arm, Shoulder and Hand (DASH) and Patient-Rated Wrist Evaluation (PRWE) scores, satisfaction, wrist range of motion, and grip strength were assessed independently. Preoperative and last follow-up standard films were compared for Lichtman stage, radiocarpal or midcarpal osteoarthritis, scapholunate and radioscaphoid angles, the Stahl index, carpal height, ulnar carpal deviation, and ulnar variance. Results: In all, 7 male and 4 female patients were reviewed. The average follow-up was 4.85 years (1-10.55 years). The average age at the time of surgery was 30.1 years (18.5-36 years). Six patients had a radial shortening at the same time and 2 others had 2 and 23 years prior to SC fusion. The lunate was not explored and always left in place. Preoperative pain was 8 (6-10) and was described as constant by all patients. Visual analogue scale (VAS) significantly decreased after surgery to 1.09 (0-2; P < .0001). Wrist range of motion was mildly but not significantly ( P = .45) improved at follow-up. Preoperative wrist flexion was 35.5° (20°-50°) and wrist extension was 35° (20°-70°). Postoperative wrist flexion was 42.7° (10°-95°) and wrist extension was 41.4° (30°-70°). Wrist range of motion was significantly decreased in comparison with the unaffected wrist. Pronosupination was comparable with the unaffected ( P = .01) side. Grip strength was significantly decreased ( P = .027) with 25.8 kg in comparison with the unaffected side with 34.5 kg. Nine lunates were stage 3B, and 2 were stage 3A. Radiographically, all SC fusions united. Ulnar variance was −1 mm on average. Three stage 3B patients improved to stage 3A on follow-up films. Four patients with more than 4-year follow-up had radiographic dorsal radioscaphoid and radial styloid osteophyte suggesting impingement but was not clinically symptomatic. The carpal height decrease from 1.47 to 1.2 was not statistically significant ( P = .09). Ulnar carpal deviation and Stahl index were unchanged. The radioscaphoid and scapholunate angles were restored to a normal range. Functional outcome was good: Average DASH was 30.45 and PRWE was 23.8. Nine patients thought their wrist was very good or good, and 2 thought that it was fair. Nine out of 11 patients were employed and remained so at follow-up. Two patients changed jobs to less demanding positions. Conclusion: SC fusion is a treatment option for advanced Kienböck’s disease. Pain relief is significant. Wrist range of motion remains similar to the preoperative range. Carpal collapse does not progress and keeping the lunate avoids ulnar translation. However, radiological progression of radioscaphoid arthritis may occur.