A randomized clinical trial of first metatarsophalangeal (MTP) joint hemiarthroplasty with a synthetic cartilage implant demonstrated equivalent pain, function and safety outcomes to first MTP joint arthrodesis at 2 years. The implant cohort continues to be followed under an extension of the original study and we report on prospectively determined 5+ year outcomes for subjects assessed to date. Patients treated with hemiarthroplasty implant as part of the previously mentioned trial are eligible for enrollment in the extended study (n=135). At the time of this report, 57 patients had reached the 5+ years postoperative time point, of which 5 were lost to follow-up. The remaining 52 patients with mean age of 58.5 (range, 38.0–0.0) underwent physical examination, radiographic evaluation, assessment of implant survivorship and collection of patient completed VAS pain, and Foot and Ankle Ability Measure (FAAM) sports subscale and activities of daily living (ADL) subscale scores. Mean follow-up is 5.8 (range, 4.8–8.4) years.Introduction
Methods
Patients with advanced stage hallux rigidus from 12 centers in Canada and the UK were randomized (2:1) to treatment with a small (8/10 mm) hydrogel implant (Cartiva) or 1st MTP arthrodesis. VAS pain scale, validated outcome measures (FAAM sport scale), great toe active dorsiflexion motion, secondary procedures, radiographic assessment and safety parameters were evaluated. 236 patients were initially enrolled, 17 patients withdrew prior to randomization, 17 patients withdrew after randomization and 22 were non-randomized training patients, leaving 152 implant and 50 arthrodesis patients. Standard demographics and baseline outcomes were similar for both groups. Mean VAS pain scores decreased from 6.8 and 6.9 respectively for the implant and arthrodesis groups from baseline to 1.4 and 0.7 at 24 months. Similarly, the FAAM sports score improved significantly from baseline levels of 37 and 36 to 24 months level of 77 and 82 respectively for the implant and arthrodesis groups. First MTP active dorsiflexion motion improved an average of 4° at 3 months after implant placement and was maintained at 24 months. Secondary surgeries occurred in 17 (11.2%) implant patients and 6 (12.0%) arthrodesis patients. Fourteen (9.2%) implants were removed and converted to arthrodesis and 6 (12.0%) arthrodesis patients had painful hardware requiring removal. There was no case of implant fragmentation, wear, or bone loss. Analysis of a single composite endpoint utilizing the three primary study outcomes (pain, function, and safety) showed statistical equivalence between the2groups. In patients requiring surgery for advanced stage hallux rigidus, treatment with a small synthetic cartilage implant resulted in comparable clinically important pain relief and functional outcomes compared to 1st MTP arthrodesis while preserving and often improving great toe motion. Secondary surgical intervention was similar in the implant and arthrodesis groups. Revision from a small implant plug to arthrodesis can be performed if needed.Conclusion
