Examining the Efficacy of Arthroscopic Scaphocapitate Arthrodesis for Advanced Kienbock's Disease: Clinical and Radiological Outcomes.

Background: Altering wrist biomechanics, Kienbock's disease leads to progressive carpal collapse that results in early arthritis and degenerative changes. By shifting the loading axis toward the radioscaphoid joint, scaphocapitate arthrodesis (SCA) has been reported as a salvage procedure effective in treating symptomatic patients with advanced Kienbock's disease. In this study, we aimed to evaluate the clinical and radiological outcomes of arthroscopic SCA in symptomatic patients with advanced stages of Kienbock's disease.

Methods: Between March 2010 and February 2021, we included 15 patients with symptomatic stage IIIA (n=2) and stage IIIB (n=13) Kienbock's disease who were followed up for a minimum of 24 months after arthroscopic SCA with or without lunate excision. The lunate was excised in 6 patients and retained in 9. Visual analog scale (VAS) pain score, grip strength, range of motion (ROM), active flexion-extension arc, and modified Mayo wrist score (MMWS) were measured preoperatively and at each follow-up examination after surgery. Operation-related complications and radiographic changes were also assessed.

Results: There were 13 women and 2 men, with a mean age of 57.6 years (range, 21-74 years) at the time of undergoing arthroscopic SCA. Follow-up ranged from 24 to 116 months, with an average of 56.9 ± 32.3 months. Bony union was achieved in all patients. At preoperative examination, wrist ROM (67%) and grip strength (48%) significantly decreased, compared to the contralateral wrist. At the final follow-up, there were significant improvements in VAS, grip strength, and MMWS, whereas the active wrist ROM showed no significant change. Radioscaphoid angle recovered after surgery, while radiographic carpal collapse and ulnar translation of the carpus occurred. In subgroup analysis according to excision of the lunate, there were no significant differences in VAS, MMWS, grip strength, or total ROM. However, increased ulnar translation and decreased radial deviation were noted in the lunate excision group.

Conclusions: Arthroscopic SCA achieved significant improvements in pain and wrist function in patients with advanced Kienbock's disease without any complications. Excision of the lunate when performing arthroscopic SCA seemed to induce progressive carpal ulnar translation, with no apparent clinical benefits over retaining it.