Arthroscopic scaphocapitate fusion with lunate preservation without autologous bone grafts for Lichtman stage III Kienböck disease: a retrospective observational study

Purpose: This study aimed to evaluate the outcomes of arthroscopic scaphocapitate fusion with lunate preservation, without autologous bone grafts, in stage III Kienböck disease, which causes significant wrist dysfunction due to lunate necrosis.Methods: Nine patients with stage III Kienböck disease underwent arthroscopic scaphocapitate fusion with lunate preservation from 2017 to 2022. Bone substitutes were used instead of autologous bone grafts: demineralized bone matrix, allogenic cancellous bone chips, and a bone substitute composed of hydroxyapatite combined with recombinant human bone morphogenetic protein-2. The clinical outcomes assessed were pain visual analogue scale (VAS), grip strength, wrist range of motion (ROM), Patient-Rated Wrist Evaluation (PRWE), and Disabilities of the Arm, Shoulder, and Hand (DASH) scores. Radiological assessments included bone union and modified carpal height ratio (MCHR).Results: At a mean follow-up of 22.7 months, all patients achieved bone union, with an average time to union of 8 weeks. Significant improvements were observed in wrist ROM (mean increase from 58.3° to 75.6°, p=0.001), grip strength (29.4% to 71.8% of the contralateral side, p<0.001), DASH scores (43.9 to 17.5, p<0.001), PRWE scores (45.2 to 18.0, p<0.001), and pain VAS (5.7 to 2.9, p<0.001). The mean MCHR decreased slightly from 1.41 to 1.39 (p<0.001).Conclusion: Arthroscopic scaphocapitate fusion with lunate preservation, without autologous bone grafts, effectively improved pain, function, and anatomical outcomes in stage III Kienböck disease. Further research is needed to validate these findings.