Arthroplasty of the trapeziometacarpal joint with or without bioabsorbable polylactide scaffold (RegJoint™) interposition.

The RegJoint™, a bioabsorbable polylactide scaffold, was introduced in 2011 for scaphometacarpal interposition following trapeziectomy for osteoarthritis. As previous clinical trials provided controversial results, we aimed to prove the non-inferiority of RegJoint™ interposition. In this retrospective study, first metacarpal suspension arthroplasty alone (SA) was compared to suspension with RegJoint™ interposition (RJ). Thirty-four patients with 37 treated thumbs (SA: 14; RJ: 23) were assessed clinically and radiologically at a mean follow-up of 5.3 ± 2.6 years (SA: 7.96; RJ: 3.73). Patient-reported outcomes were measured on three questionnaires (DASH, PRWE and PEM) and a visual analogue pain scale; there were no significant differences between the 2 groups. Clinical assessment comprised range of motion, opposition, pain, first-ray length, hand span, prominence, instability, force and sensitivity to touch. The RJ group showed significantly better palmar abduction (p = 0.026); the other outcome parameters were comparable in the 2 groups. Follow-up radiographs showed osteolysis in 2 SA hands and 3 RJ hands (p = 0.551). First-ray length had decreased by a mean 4.7 ± 2.7 mm at follow-up (SA: -3.8; RJ: -5.2; p = 0.056). No signs of adverse tissue reactions were observed. We conclude that RegJoint™ spacers do not produce more complications than suspension alone but provide no added benefit.