Comparison of the outcomes of first metatarsophalangeal joint arthrodesis by locking plate and compression screw in patients with severe hallux valgus or hallux valgus revision

Introduction: Arthrodesis of the first metatarsophalangeal joint (MTP1) is indicated for hallux rigidus, septic arthritis, severe hallux valgus (HV) or HV revision. Few studies have compared the functional and radiographic outcomes between indications. The goal of this study was to compare the results of MTP1 arthrodesis in patients with severe HV or HV revision at 6 months postoperative. The hypothesis was that there are no differences in the fusion rate, functional scores and radiological correction between the two groups. Materials and methods: This was a retrospective, observational, single-center study conducted between January 1, 2018 and July 31, 2021. The inclusion criteria were patients treated for severe HV or HV revision by MTP1 arthrodesis with a compression screw and locking plate who were at least 18 years of age. The exclusion criteria were a history of septic arthritis of MTP1 without prior HV surgery, primary hallux rigidus, rheumatoid arthritis, incomplete medical record. The functional outcomes consisted of the Foot Function Index (FFi-f) and the European Foot and Ankle Society (EFAS) score. Radiographs were made to evaluate preoperative and postoperative deformity, the correction and the fusion rate. These outcomes were compared between two groups: severe HV and HV revision. Results: An analysis was done of 58 cases of MTP1 arthrodesis: 45 severe HV and 13 HV revisions. The mean patient age was 66 years, and the mean follow-up was 15.7 months. There were no significant differences between the two groups in the postoperative functional scores: EFAS (p = 0.85) and FFI-f (p = 0.14). At the final review, there were no significant differences between the two groups in the foot angle measurements (hallux valgus angle, p = 0.08 and intermetatarsal angle, p = 0.15) and fusion rate (p = 0.89) with a 93% fusion rate in patients with severe HV and 92% in patients with HV revision. Conclusion: Given the good radiographic and functional outcomes, MTP1 arthrodesis by locking plate and compression screw is indicated as a first line surgical treatment for patients with severe HV or for patients undergoing HV revision. There is no evidence of a significant difference in the functional scores, fusion rate and radiographic correction between these two indications. Level of proof: IV; retrospective case series