Anatomic considerations of the peroneal nerve for division of the fibula during high tibial osteotomy.

Twenty legs in 10 cadavers were dissected to determine the course of the deep peroneal nerve from its origin to its termination. Particular attention was paid to defining: (1) its relationship to palpable landmarks, (2) the angle of the course of its proximal portion against the long axis of the fibula, (3) distribution of the proximal branch to the extensor hallucis longus muscle, and (4) safe areas of osteotomy in the proximal fibula during high tibial osteotomy. The extensor hallucis longus was often supplied by only one branch from the deep peroneal nerve at 99.8 mm (31.7%) distally from the apex of the fibula; this seems to explain why osteotomy of the fibula at its proximal one third often causes paralysis of this muscle. The findings suggest that safe areas for osteotomy in the proximal fibula during high tibial osteotomy are located up to 20.5 mm (6.5%) distal to the tip of the fibular head and that the safe angle of a periosteal incision against the fibular neck area is 64.1 degrees.