Mechanics of the hallux valgus foot and the effect of Keller's operation.

Using a system for measuring the load distribution under the foot, patients with hallux valgus were compared, before and after undergoing Keller's operation, with a group of normal subjects. Preoperatively the patients showed reduced loading under all their toes and increased loading under their lateral metatarsal heads; the decrease under the hallux was found to correlate with an increase in hallux valgus angle. Postoperatively there was a further decrease in loading under the hallux and an increase under the first metatarsal head.