Surface replacing arthroplasty of the proximal interphalangeal joint using the CapFlex-PIP implant: a prospective study with 5-year outcomes.

The purpose of this prospective study was to evaluate the 5-year outcomes in patients after proximal interphalangeal joint arthroplasty using the surface replacing implant, CapFlex-PIP. Ninety-two prosthesis were implanted and 65 patients with 68 implants were available for follow-up. The brief Michigan Hand Outcomes Questionnaire score improved significantly from 45 (SD 15) before surgery to 71 (SD 17) at 5 years. On the numeric rating scale, pain during activities decreased significantly from 6.4 (SD 1.9) to 1.8 (SD 1.9). Range of motion of the joints increased significantly from 45° (SD 21) to 54° (SD 24). An axis deviation of more than 5° was found in 65% of the joints before surgery, but only in 25% at 5 years. Soft tissue reoperations were performed on eight patients. Four out of 92 implants underwent revision for stiffness or implant loosening. In three implants, the distal component migrated without needing revision. Overall, the CapFlex-PIP implant demonstrates favourable medium-term results in surface replacing arthroplasty of the proximal interphalangeal joint.