A method of predicting the degree of functional correction of the metatarsus primus varus with a distal lateral displacement osteotomy in hallux valgus.

Metatarsus primus varus may be an important pathologic component in hallux valgus deformity. The correction of the pathologic intermetatarsal angle M1 M2 is essential for providing an acceptable alignment of the hallux. The distal lateral displacement osteotomy of the first metatarsal (Chevron or Mitchell) provides correction of the intermetatarsal angle M1 M2. The present paper describes a simple method of calculating preoperatively the maximum possible correction through such osteotomies. This method, based on the measurement of the length of the first metatarsal and the width at the osteotomy site, projects the amount of correction and, furthermore, provides the limits of angular correction through such osteotomies performed distally.