The postoperative stability of the first metatarsal

ABSTRACT

The hallux valgus deformity is characterised by an increased first intermetatarsal angle, which can be reduced by osteotomies on the first metatarsal bone, such as the Proximal osteotomy and the Scarf shaft osteotomy. Osteotomy and subsequent screw fixations were performed on 18 matched pairs of cadaveric specimens to compare the postoperative stability of these two common types of operative correction. Biomechanical testing with plantar force was carried out and failure load was measured for each specimen. The results indicate that the threaded bones provide a high postoperative loading capacity. When maximal strain was exceeded, the specimens failed in the proximal third, irrespective of the type of osteotomy. Moreover, we found that in contrast to the living age the mineral density and the individual geometry of the bone have a marked influence on the postoperative loading capacity. Finally, static biomechanical studies demonstrated that the Scarf osteotomy is significantly more stable than the commonly used Proximal osteotomy. Regarding the early postoperative mobilization of the patients concerned, the Scarf osteotomy proved to be superior, but the Proximal osteotomy requires a more cautious rehabilitation program (AU)

RESUMEN

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