A biomechanical comparison of the Z step-cut and basilar crescentic osteotomies of the first metatarsal.

The basilar crescentic osteotomy is a popular procedure for the correction of moderate to severe hallux valgus deformity. Dorsiflexion due to malposition of the osteotomy, fixation failure, or late contracture of the soft tissues can lead to lateral metatarsalgia. This study compares the mechanical properties of the Z step cut osteotomy Scarff to those of the crescentic osteotomy in cantilever-bending. The ultimate load, maximum bending moment and energy absorbed were significantly greater for the Scarff osteotomy compared to those in the crescentic osteotomy (p < 0.001). Values for stiffness did not differ between the two osteotomies. Failure of the cortical bone-bridge between the screw-hole and the osteotomy was observed in all crescentic osteotomies, while fracture of the proximal dorsal bridge was seen in all Scarff osteotomies.