Intermetatarsal angle and hallux abductus angle reduction after first metatarsophalangeal joint arthrodesis in mild, moderate, and severe hallux valgus

Background: First metatarsophalangeal joint fusion is a commonly used procedure for treating many pathologic disorders of the first ray. Historically, hallux valgus deformity with severely increased intermetatarsal angle or metatarsus primus adductus indicated need for a proximal metatarsal procedure. However, the effectiveness and reliability of first metatarsophalangeal joint arthrodesis in reducing the intermetatarsal angle has been increasingly described in the literature. We compared findings at our institution with current literature for further validation of this well-accepted procedure in correcting hallux valgus deformity with high intermetatarsal angle. Methods: Weightbearing preoperative and postoperative radiographs of 43 patients, 31 women and 12 men, meeting the inclusion and exclusion criteria were identified. Two independent investigators measured the hallux abductus and intermetatarsal angles. Preoperative and postoperative measurements for each angle were compared and average reduction calculated. The data were further analyzed by grouping deformities as mild, moderate, and severe. Mean follow-up was 10 months. Results: The overall mean preoperative intermetatarsal and hallux abductus angles decreased significantly (from 13.098 to 9.338 and from 23.728 to 12.198, respectively; both P < .01). When grouping deformities as mild, moderate, and severe, all of the categories maintained reduction of intermetatarsal and hallux abductus angles (P < .01). Furthermore, the mean reduction of the intermetatarsal and hallux abductus angles seemed to correlate with preoperative deformity severity. Conclusions: In patients undergoing correction of hallux valgus deformity, first metatarsophalangeal joint arthrodesis produced consistent reductions in the intermeta-tarsal and hallux abductus angles. Furthermore, these findings are consistent with those reported by other institutions.