Mechanical Comparison of Biplanar Proximal Closing Wedge Osteotomy with Plantar Plate Fixation Versus Crescentic Osteotomy with Screw Fixation for the Correction of Metatarsus Primus Varus

Abstract

Proximal crescentic metatarsal osteotomy is a clinically successful technique for correcting metatarsus primus varus in hallux valgus surgery. However, there have been instances of dorsal elevation of the metatarsal head with this technique. Mechanical testing on 10 matched pairs of cadaver feet was performed to evaluate a new technique combining a biplanar closing wedge osteotomy and plantar plate fixation versus crescentic metatarsal osteotomy. The specimens were tested in cantilever-bending mode on an MTS Mini Bionix test frame. The mean load-to-failure values were 127.2 ± 81.9 N (SD) for biplanar osteotomy with plate fixation and 44.9 ± 43.3 N for crescentic osteotomy ( P = 0.019); the mean stiffness values at the initial portion of the load-deflection curve were 83.11 ± 73.76 N/mm and 31.95 ± 43.00 N/mm, respectively ( P = 0.012). The biplanar wedge osteotomy with plantar plate fixation demonstrated significantly stronger fixation than the crescentic osteotomy, with higher mean load-to-failure and stiffness values. This newly described technique may provide an acceptable alternative for patients at risk for dorsal elevation of the metatarsal, particularly those who are noncompliant or have osteopenia. Clinical study will determine whether this new technique offers satisfactory long-term results.