Studies have compared outcomes of first metatarsophalangeal joint (MTPJ1) implant hemiarthroplasty and arthrodesis, but there is a paucity of data on the influence of patient factors on outcomes. We evaluated data from a prospective, RCT of MTPJ1 implant hemiarthroplasty (Cartiva) and arthrodesis to determine the association between patient factors and clinical outcomes. Patients ≥18 years with Coughlin hallux rigidus grade 2, 3, or 4 were treated with implant MTPJ1 hemiarthroplasty or arthrodesis. Pain VAS, Foot and Ankle Ability Measure (FAAM) Sports and ADL, and SF-36 PF scores were obtained preoperatively, and at 2, 6, 12, 24, 52 and 104 weeks postoperatively. Final outcomes, MTPJ1 active peak dorsiflexion, secondary procedures, radiographs and safety parameters were evaluated for 129 implant hemiarthroplasties and 47 arthrodeses. Composite primary endpoint criteria for clinical success included pain reduction ≥30%, maintenance/improvement in function, and no radiographic complications or secondary surgical intervention at 24 months. Predictor variables included: grade; gender; age; BMI; symptom duration; prior MTPJ1 surgery; preoperative hallux valgus angle, ROM, and pain. Two-sided Fisher's Exact test was used (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
