Clinical outcomes of modified Mitchell's osteotomy and shortening oblique osteotomy for forefoot deformities with hallux valgus due to rheumatoid arthritis: A retrospective analysis.

Introduction: Rheumatoid arthritis (RA) is a systemic autoimmune disease that primarily affects the synovial membrane, leading to progressive joint destruction. Among RA-related deformities, forefoot deformities are particularly common, causing severe pain, gait disturbances, and a significant decline in patient quality of life. Typical forefoot deformities observed in patients with RA include hallux valgus (HV), hammer toe deformities, and plantar callosities, all of which require appropriate therapeutic intervention. We aimed to evaluate the clinical outcomes of modified Mitchell's osteotomy with shortening oblique osteotomy (SOO) for forefoot deformities in patients with RA.

Methods: Twenty-four patients (31 feet) underwent surgery between 2005 and 2023. The cohort included 22 women (29 feet) and two men (2 feet) with a mean age of 59 ± 12 years and disease duration of 20.3 ± 8.7 years. Clinical outcomes were assessed using the Japanese Society for Surgery of the Foot (JSSF) RA Foot and Ankle Scale and radiographic evaluations.

Results: At a mean follow-up of 10.1 years, the JSSF scale score improved significantly from 57.9 to 77.1 points; HV angle (HVA) significantly improved from 31.7° to 17.1°; and the 1st to 5th intermetatarsal angles (M1M5A) significantly improved from 29.3° to 20.6°. The 28 joint-Disease activity score with erythrocyte sedimentation rate significantly improved from 2.75 to 2.20. Complications included recurrence of callosities in six feet (16.1%), metatarsal phalangeal joint subluxation in 13 feet (8.4%), appearance of HV deformity in 10 feet (32.3%), and infections in two feet (6.5%). No non-union was observed.

Conclusions: Modified Mitchell's osteotomy with SOO significantly reduced pain and improved walking ability in patients with RA. The procedure also achieved a remarkable degree of radiographic correction, particularly a reduction in HVA and M1M5A, contributing to improved forefoot alignment. These findings suggest that the procedure provides clear benefits. Careful attention should be paid to potential postoperative complications such as the appearance of HV deformity and infection.