The intraosseous and extraosseous vascular supply of the fifth metatarsal: implications for fifth metatarsal osteotomy.

BACKGROUND: Osteotomies of the fifth metatarsal may disrupt the nutrient artery and result in nonunion. The location of the nutrient artery foramen relative to the location of common osteotomies has not been described. The goal of this study was to describe the vascular supply of the proximal fifth metatarsal, including the artery of origin of the nutrient artery and the location of the nutrient artery foramen.

METHODS: Fifty-six adult cadaver specimens were amputated below the knee. The anterior tibial, posterior tibial, and peroneal arteries were injected with India ink and Ward's Blue Latex. The specimens were frozen for 48 hours and then thawed to room temperature. The soft tissues were débrided with sodium hypochlorite, and the extraosseous vascularity was recorded. The fifth metatarsal was then removed and the intraosseous vascular anatomy elucidated using a modified Spälteholz technique.

RESULTS: The dorsalis pedis, posterior tibial, and peroneal arteries branch in predictable patterns to supply the fifth metatarsal. The nutrient artery arose from the fourth plantar metatarsal artery in 100% of specimens and inserted into the plantar medial diaphysis in 83% of specimens. The nutrient artery foramen was an average of 26.8 mm (range, 19-40) from the medial aspect of the base of the fifth metatarsal.

CONCLUSIONS: When an operative approach to the fifth metatarsal is planned, care should be taken to avoid stripping the bone on the plantar and medial aspects.

CLINICAL RELEVANCE: Osteotomies placed within the proximal 40 mm of the bone carry a risk of disrupting the nutrient artery, resulting in possible nonunion.