The effect of chevron osteotomy with lateral capsular release on the blood supply to the first metatarsal head.

The chevron osteotomy is one of the most widely used distal metatarsal osteotomies for the treatment of hallux valgus in adults. Because the osteotomy interrupts the intraosseous blood supply to the metatarsal head, there has always been a concern that the operation could produce osteonecrosis of the metatarsal head, particularly if the important extraosseous blood supply was also damaged. We used latex injection and a modified Spalteholz technique in cadaveric specimens to demonstrate the effect of the chevron osteotomy, with and without lateral capsular release, on the vascular supply to the first metatarsal head. We found an extensive network of extraosseous vasculature to the metatarsal head both proximal and distal to the site of the osteotomy. Both of these vascular networks were preserved when the osteotomy was done properly. Also, an extensive plantar and plantar lateral network of vessels provided circulation to the head. Potential technical flaws in the performance of the osteotomy included cutting of the first dorsal metatarsal artery by overpenetration of the saw blade and incorrect placement of the proximal arms of the osteotomy inside the joint capsule. These technical errors, alone or in conjunction with extensive capsular stripping, can result in damage to the vessels that supply the metatarsal head.