Association between patient factors and outcome of synthetic cartilage hemiarthroplasty (Cartiva) versus first metatarsophalangeal joint arthrodesis in advanced hallux rigidus

A. Goldberg, M. Glazebrook, T. Daniels, G. de Vries, M.E. Pedersen, A.S.E. Younger, D. Singh, C. Blundell, A. Sakellariou, J. Baumhauer, The Cartiva Motion Study Group

Introduction: 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.

Methods: 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 (p< 0.05).

Results: Patient demographics and baseline outcome measures were similar. Success rates between implant MTPJ1 hemiarthroplasty and arthrodesis were similar when stratified by hallux rigidus grade, gender, age, BMI, symptom duration, prior MTPJ1 surgery status, and preoperative VAS pain, hallux valgus and ROM (p>0.05).

Conclusion: Synthetic cartilage implant hemiarthroplasty (Cartiva) is an appropriate treatment for patients with hallux rigidus grade 2, 3 or 4 and is a reasonable choice in hallux rigidus in patients with < 20 degrees HVA, with a high degree of preoperative stiffness, irrespective of gender, age, BMI, hallux rigidus grade, preoperative pain, or duration of symptoms, in contrast to what might have been expected.