Minimally invasive arthroscopy-assisted arthrodesis for thumb carpometacarpal osteoarthritis

Introduction Arthrodesis is a reliable surgical procedure for treatment of thumb carpometacarpal (CMC) osteoarthritis that provides hand strength and pain relief. Locking plate fixation is a common technique that provides rigid fixation and a high rate of bone union; however, it requires extensive surgical exploration of the first metacarpal and trapezium. Here, we report the surgical outcome of minimally invasive arthroscopy-assisted thumb CMC arthrodesis that preserves soft tissue supplying the blood flow to the bones. Materials and methods Nine thumbs of nine patients who underwent arthroscopy-assisted thumb CMC arthrodesis were retrospectively analysed (mean postoperative follow-up, 19.7 months). We investigated the time from surgery to bone union, grip strength, pinch strength (pulp and key), range of motion (ROM) of the thumb, visual analogue scale (VAS) score for pain, Disabilities of Arm, Shoulder, and Hand (DASH) score, and Hand20 questionnaire score preoperatively and at the final follow-up. Results Bone union was observed in eight of the nine patients. The mean time to bone union was 2.9 months (range 8 weeks–9 months). Although grip strength changed from 24.0 kg preoperatively to 25.8 kg at the final follow-up (not significant), the pulp pinch strength and key pinch strength significantly increased from 2.3 kg and 3.7 kg preoperatively to 3.8 kg and 5.6 kg at the final follow-up, respectively. No significant change occurred in the thumb ROM. The DASH score, Hand20 questionnaire score, and VAS score for pain significantly improved from 29.8, 42.2, and 78.4 preoperatively to 12.4, 11.2, and 13.2 at the final follow-up, respectively. Non-union was observed in one patient. No other complications were observed. Conclusions Arthroscopy-assisted arthrodesis is a valuable procedure for thumb CMC osteoarthritis. However, the learning curve for this procedure must be overcome before the operative time can be shortened and successful bone union and satisfactory outcomes achieved.