Thumb carpometacarpal osteoarthritis: trapeziectomy versus pyrocarbon interposition implant (Pi2) arthroplasty

We retrospectively compared the short-term outcomes of 18 thumbs that had a trapeziectomy and 18 that had a pyrocarbon interposition implant (Pi2) arthroplasty in 33 patients. We measured the Disability of the Arm, Shoulder, and Hand (DASH) and Short Form 36 (SF-36) scores at a mean of 20 months. Pain severity was assessed using a visual analogue scale (VAS), and level of patient satisfaction was assessed using a 5-point scale. The mean DASH scores at follow up were 27 for those that had a trapeziectomy and 35 for those that had a Pi2 arthroplasty (p = 0.001). There was no difference in the VAS for pain, SF-36 scores, or other parameters assessed. Six out of 18 (33%) thumbs in the Pi2 group had multiple operations, usually for dislocation or subluxation of the implant. The early results of Pi2 arthroplasty show a high complication rate compared with trapeziectomy and no identifiable benefit.