Clinical outcomes following interpositional arthroplasty for advanced hallux rigidus: A retrospective case series

Abstract

Objective: To evaluate clinical and functional outcomes following interpositional arthroplasty in a Brazilian cohort. Methods: This retrospective case series included 10 patients with grade III-IV hallux rigidus (HR) treated between January and September 2025. All procedures were performed by a single experienced foot and ankle surgeon. Inclusion criteria were failure of at least six months of conservative treatment. Exclusion criteria included diabetes mellitus, rheumatoid arthritis, and prior first metatarsophalangeal joint (MTPJ) surgery. Outcomes were assessed using the visual analog scale (VAS) and the American Orthopaedic Foot & Ankle Society (AOFAS) score preoperatively and at four months postoperatively. Statistical analysis included descriptive statistics, the Shapiro-Wilk test, and the Wilcoxon signed-rank test, with significance set at p < 0.05. Results: The cohort was predominantly female (90.00%, 9/10), with a mean age of 58.700 ± 11.180 years. All patients achieved greater than 30° of first MTPJ range of motion at final follow-up. Radiographs demonstrated adequate bone resection and preservation of joint space. Pain improved progressively, with median VAS decreasing from 7.000 (IQR 6.500-8.000) preoperatively to 1.500 at four months (IQR 0.000-2.000). Functional outcomes improved significantly, with median AOFAS increasing from 52.000 (IQR 42.000-66.750) preoperatively to 84.000 (IQR: 84.000-99.000) at final follow-up. Conclusion: Interpositional arthroplasty resulted in significant improvements in pain and function while preserving joint motion in patients with advanced hallux valgus. This technique represents a viable motion-preserving alternative for selected patients who wish to avoid arthrodesis. Level of evidence IV; Retrospective Study.