Behavior of the first cuneiform in the surgical correction of metatarsus adductus

Abstract

Purpose Metatarsus adductus is an adduction deformity of the forefoot. Our purpose is to uphold the claim that the main anomaly is to be found on the cuneiform side of the cuneo-metatarsal joint and that the growth of the medial cuneiform is fundamental for correction further to capsulotomy. Materials and methods This is a radiological study of 23 children with idiopathic or clubfoot-related metatarsus adductus subjected between 1982 and 2000 to a release of the cuneiform metatarsal joint. X-rays were taken of the 30 operated feet and of 12 contralateral feet used as controls. The following measurements were made: cuneiform-metatarsal angle, distal inclination angle of the medial cuneiform bone, angle formed between the latter surface and the first metatarsal and the proximal articular angle of the first metatarsal. The mean pre-op, immediate post-op and post-op final values of these angles were compared using the relevant statistical tests. Results As regards idiopathic metatarsus adductus, the cuneiform metatarsal angle went from a preop value of 150.4° to 170.2° at the end of follow-up; the distal inclination angle of the medial cuneiform went from 62° to 81.1°; and the angle formed between the latter surface and the first metatarsal and the proximal articular angle of the first metatarsal went from 88.4° to 89.1°. With respect to clubfoot-related metatarsus adductus, the cuneiform metatarsal angle went from a preop value of 155.3° to 169.7°, the distal inclination angle of the medial cuneiform went from 61.9° to 79.7°, and the angle formed between the latter surface and the first metatarsal and the proximal articular angle of the first metatarsal went from 88.3° to 90°. On the healthy side, the angle values showed virtually no changes. Conclusions The obliqueness of the medial cuneiform-metatarsal joint is closely related to metatarsus adductus. Post-surgical correction also takes place at the expense of this bone, which tends to fill the space created by the capsulotomy.