Comparison of two proximal osteotomies for the treatment of hallux valgus

Abstract

Moderate to severe deformities of hallux valgus can be corrected with combination procedures, such as a proximal crescentic metatarsal osteotomy and a distal soft tissue procedure. Because crescentic osteotomy allows for motion in all planes, inadvertent metatarsal elevation can result in metatarsalgia. The crescentic shelf osteotomy (CSO) provides a plantar shelf, decreasing the complication of dorsiflexion fixation. Eighteen polyurethane foam specimens in three groups were prepared and tested to failure on a servohydraulic Instron testing machine. The mechanical characteristics of stiffness, deformation, ultimate failure load, and stored energy were compared between single-screw fixation crescentic osteotomies and single- and dual-screw CSOs in molded polyurethane foam metatarsal sawbones. In addition, 12 cadaver specimens were randomly divided, and a CSO or crescentic osteotomy was performed. Preosteotomy and postosteotomy intermetatarsal, dorsiflexion, and pronation angles were compared from radiograph measurements. The results showed comparable mechanical characteristics among the groups, as measured by the area under the curve (P=0.95), ultimate failure load (P=0.35), deformation (P=0.63), and stiffness (P=0.21). Greater improvements were seen in the CSO group compared with the crescentic osteotomy group in correction of the intermetatarsal angle (4.8 degrees compared with 3.2 degrees) and of the first metatarsal plantarflexion (2.3 degrees compared with 3.2 degrees of dorsiflexion). However, these differences were insignificant (P=0.10 and P=0.41) with the numbers available. Compared with the crescentic osteotomy, a CSO may possibly provide easier initial fixation but similar mechanical properties.