MatOrtho Proximal Interphalangeal Joint Arthroplasty via Lateral Approach: Minimum 2-Year Follow-Up

Background: The MatOrtho implant is a cementless, mobile-bearing surface arthroplasty with a cobalt-chromium metal-on polyethylene articulation designed to treat osteoarthritis of the PIP joint. Early results for the prosthesis inserted through a dorsal approach have demonstrated good pain relief but no significant improvement in range of motion. In an attempt to improve the range of motion the senior author has changed his surgical practice to inserting the MatOrtho implant via a lateral approach. The purpose of this study is to assess the outcome of this change of surgical technique. Methods: Consecutive patients with osteoarthritis who underwent PIPJ replacement surgery via the lateral approach at a single institution, with a minimum follow-up period of 2 years were identified. A visual analogue score was used to assess pain. Grip strength, range of motion and functional outcomes scores were collected. Results: A total of 46 PIP joint arthroplasties were performed in 29 patients. Ten patients were lost to follow-up resulting in 33 PIP joint arthroplasties reviewed in 19 patients. Six implants failed. The mean follow-up time at the final follow-up for the remaining 25 prosthesis was 34.2 months (range 24-52). Range of motion improved from a mean of 37.2 preoperatively to a mean of 57.9 postoperatively. This was statistically significant (p = 0.0007). There was also a significant improvement in pain and functional outcome scores but not for grip strength. Conclusions: The MatOrtho PIPJ replacement delivers significant improvements in pain relief and functional outcome scores, as well as increased range of motion when the surgical procedure is performed through a lateral approach. There are, however, limitations to the use of this implant. Currently we do not consider this implant when there is instability or deformity of the PIP joint preoperatively.