Retrospective analysis of scaphoid trapezium pyrocarbon implant intervention in STT arthritis: a 3-year follow-up study.

Aim: The purpose of this study was to evaluate clinical, patient rated and radiological outcome of the scaphoid trapezium pyrocarbon implant (STPI) at a minimum of three years follow-up.

Methods: Consecutive patients operated with the STPI due to scaphotrapeziotrapezoidal (STT) arthritis between 2012 and 2019 were included. Patients were evaluated preoperatively and annually after surgery for range of motion, grip strength, key pinch, quick-DASH, pain, and satisfaction. Radiographs were evaluated for implant position, signs of dorsal intercalated segment instability (DISI), capitolunate (CL) angle, scapholunate (SL) distance, and presence of osteophytes.

Results: Twenty-six patients (29 implants) were included. Seven implants were revised during the follow up, mainly due to pain: three implants were removed, four patients received a new STPI of a different size, leaving 22 implants in 20 patients available for follow up, 9 males and 11 females. Median age was 61.7 years (51-78 years). Median follow-up time was 68 months (37-105 months). Comparing preoperative status to the last follow-up, wrist extension and deviation, thumb abduction, and grip strength did not change. Key Pinch, quick DASH, pain, and patient satisfaction improved significantly at last follow-up. Radiographic signs of DISI were seen in six cases preoperatively and in 12 cases at last follow-up.

Conlusion: At a minimum of three years follow-up, the STPI used for STT-arthritis improve pain, quick-DASH result, and patient satisfaction significantly. ROM and grip strength did not change compared to preoperative values. Radiographic signs of carpal instability were common at the follow-up and the revision rate was high.