Abstract
Introduction: A retrospective review was conducted on individuals who have undergone Mitchell osteotomy for mild to moderate hallux valgus deformity. Hallux valgus leads to altered load bearing function of the foot and correction of deformity might result in shortening of the first metatarsal. Transfer metatarsalgia is one of the common postoperative complication. This study aims to look at the restoration of load bearing function of the foot post deformity correction.
Methods: Patients with preoperative intermetatarsal angle of less than 14 degrees were included. Clinical records and radiographs were reviewed. Clinical evaluation done with AOFAS scores and plantar pressures recorded using musgrave system. The foot was divided into 7 regions: first metatarsal head, 2nd & 3rd metatarsal heads, 4th & 5th metatarsal heads, midfoot, heel, hallux and lesser toes. Average pressure, peak pressure distribution and contact time of all seven regions were analysed. A control group of 15 individuals with twenty normal feet were included for comparison. Statistical analysis was done with analysis of variance of the means and Pearson correlation tests.
Results: Seventeen mitchell osteotomy was performed on 13 patients with follow up ranging from 14 to 66 months, a mean of 34 months. Most of our study group were females with an age range of 25 to 71 years, a mean of 53 years. The mean postoperative AOFAS scores were 87 and a median of 90 out of 100. Pedobarograph findings: Statistically significant reduced average pressure, peak pressure and contact time were noted under hallux when compared to the normal control group. The peak pressures were reduced at all forefoot regions but statistically insignificant. Otherwise, the pressure distribution, contact time and center of pressure progression were similar to the normal feet. On analysis of correlation between the parameters observed, reduced pressure distribution under first metatarsal head lead to increased pressures under 4th, 5th metatarsal heads and lesser toes. Significant correlation found between the pressure distribution under hallux and the AOFAS scores, which reveals the outcome of procedure, depends on the load bearing characteristics of hallux and not the first MT head.
Conclusion: Mitchell osteotomy restores the load bearing function of the feet to near normal except hallux, which may affect the outcome of the procedure.
Theses abstracts were prepared by Professor Roger Lemaire. Correspondence should be addressed to EFORT Central Office, Freihofstrasse 22, CH-8700 Küsnacht, Switzerland.
