High Implant Failure Rate in Patients with Arthrodesis for Thumb Carpometacarpal Joint Osteoarthritis

Abstract Purpose Thumb carpometacarpal (CMC) arthrodesis is a common surgical procedure used to treat osteoarthritis. However, the high complication rate can deter surgeons and patients from choosing this procedure. This study aimed to compare the implant failure rates of the different fixation techniques used in thumb CMC arthrodesis. Methods This retrospective study included 38 patients who underwent thumb CMC arthrodesis between June 2015 and May 2024. We defined implant failure, including screw dislodgement or locking mechanism failure, as the primary outcome and performed multinomial logistic regression analysis. The outcomes in each implant cohort were compared. Demographics, clinical outcomes, and implant types were analysed. Results In the multivariate analysis, implant choice was a significant prognostic factor for implant failure, which occurred in 11 (29%) patients. The APTUS Hand 2.0 plate showed significantly higher implant failure rates (73%) than the VariAx hand 2.3 (0%) and headless screws (0%). Other complications included non-union (11%), nerve injury (3%), and metal allergy (3%). Although the two headless screw cohorts were associated with longer casting times and lower EQ-5D scores, they showed less bone grafting and fewer complications. Conclusions The locking mechanism of the APTUS Hand 2.0 plate may be inadequate for the forces applied to the thumb joint, resulting in higher implant failure rates. Future studies are required to evaluate the long-term outcomes and biomechanics of different fixation techniques. Although thumb CMC arthrodesis is an effective treatment modality, careful implant selection is crucial to minimise complications. The study’s findings indicate a preference for headless screws.