Effect of Surgical Procedures for Rheumatoid Forefoot Deformities on Radiographic Foot Length and Width Variations

Background: The number of patients with rheumatoid arthritis (RA) undergoing forefoot arthroplasty has increased to better control the disease. Despite patients frequently expressing concerns regarding postoperative foot appearance and footwear-related expectations, no study has investigated postoperative changes in foot length and width in patients with RA. The aim of this study was to evaluate the effect of surgical procedures for rheumatoid forefoot deformities on variations in radiologically determined foot length and width. Methods: In total, 72 feet of 50 women and 3 men (average age: 66.7 years) underwent joint-preserving arthroplasty (n = 33) and arthrodesis of the first metatarsophalangeal joint with shortening osteotomy of the lesser metatarsals or resection arthroplasty of the lesser metatarsal heads (n = 39); procedures were carried out in our institute from August 2013 to February 2020. The mean disease duration was 23.5 years, and the average follow-up period was 17.5 months. Pre- and postoperative hallux valgus angle (HVA), intermetatarsal angle (IMA) of the first and second metatarsals (M1M2A), and IMA of the first and fifth metatarsals (M1M5A) were measured on weightbearing radiographs as well as foot length and width. We also evaluated the correlation between changes in radiographic parameters and variations in radiologically determined foot length and width. Results: Radiologically determined foot width changed significantly from 10.1 cm to 9.7 cm (p < 0.01), while no significant difference was found between pre- and postoperative radiologically determined foot length. HVA, M1M2A, and M1M5A were significantly improved after the surgery (p < 0.01, p < 0.01, and p < 0.01, respectively). A significant negative correlation was found between the variation in radiologically determined foot length and changes in HVA (r = -0.29, p = 0.02) and M1M5A (r = -0.23, p < 0.05), while a significant positive correlation was found between the variation in the foot width and changes in HVA (r = 0.34, p < 0.01), M1M2A (r = 0.55, p < 0.01), and M1M5A (r = 0.45, p < 0.01). There were no significant differences between operative procedures regarding variation in radiologically determined foot length and width. Conclusions: Surgical procedure for rheumatoid forefoot deformity improved radiographic parameters and reduced radiographic foot width while maintaining foot length.