Pyrocardan Implant Arthroplasty for Carpometacarpal Osteoarthritis of the Thumb: A Comparative Study with a Historical Control Group.

New and improved surgical techniques are warranted to treat osteoarthritis of the thumb carpometacarpal joint (CMC-1). The Pyrocardan implant yields striking results but only few series exist, making the evidence scarce.  The aim of this study was to conduct a prospective series using the Pyrocardan implant.  We compared the outcomes to a matched historical control group of patients operated on with ligament reconstruction and tendon interposition. The hypothesis was that the Pyrocardan implant would yield better patient-reported outcomes as well as the procedure would be safe and effective in relieving symptoms of CMC-1 osteoarthritis. In total, 30 patients were included in the prospective series. These 30 patients were compared, in a 1:3 design, to a matched historical group.  Results were promising with visual analogue scale scores of 0.7 (rest) and 2.1 (function), key-pinch score of 5.1 kg, and shortened Disability of the Arm, Shoulder, and Hand score of 14.3 after 1 year when using the Pyrocardan implant. The revision rate was 10%. We found no evidence of subsidence of the thumb. We found no differences in patient-reported outcomes between the two groups.  In conclusion, the Pyrocardan implant is a viable option in the treatment of CMC-1 osteoarthritis but with a significant revision rate. When comparing the Pyrocardan implant to a historical control group, we failed to find any differences in patient-reported outcomes.  IV - case series.