Five-year outcomes of a synthetic cartilage implant for the first metatarsophalangeal joint in advanced hallux rigidus

T. Daniels, Cartiva study group

Introduction/Purpose: A randomized clinical trial of first MTP joint hemiarthroplasty with a synthetic cartilage implant demonstrated equivalent pain, function and safety outcomes to first MTP joint arthrodesis at 2 years. Recognizing that many hemiarthroplasty and total toe implants have initially good results that deteriorate over time, the purpose of this study was to prospectively assess the safety and efficacy outcomes for the synthetic cartilage implant population and to determine if the excellent outcomes were maintained at >5 years.

Methods: One hundred nineteen patients were evaluated at 5+ years; 23 could not be reached for follow-up, but implant status was available for 7 of these subjects. Patients completed a pain visual analogue scale (VAS) and Foot and Ankle Ability Measure (FAAM) Sports and Activities of Daily Living (ADL) scores, preoperatively and at 2, 6, 12, 26, 52, 104 and 260 weeks postoperatively. Minimal clinically important differences are: ≥30% difference for pain VAS, 9 points for FAAM Sports, and 8 points for FAAM ADL. Great toe active dorsiflexion, weight-bearing radiographs, secondary procedures, and safety parameters were evaluated.

Results: Of 119 patients available at mean 5.8 years follow-up (SD ±0.7; range: 4.4-8.0), 9 underwent implant removal and conversion to fusion in years 2-5, leaving 106 patients. The implant survival rate was 92.4% at 5.8 years. Pain and function outcomes at 5.8 years were similar to those at 2 years. VAS Pain, FAAM Sports, ADL Scores were maintained or improved at 5.8 years. No evidence of avascular necrosis, device migration or fragmentation was observed. There were no unanticipated safety events through 5.8 years. Ninety-three (93%) percent would have the procedure again.

Conclusion: The synthetic cartilage hemiarthroplasty implant continues to demonstrate safety and efficacy for the treatment of advanced first MTP joint osteoarthritis with evidence of therapeutic effect and acceptable safety profile at 5.8 years.