Assessment of foot disorders using biomechanical analysis of foot loads during locomotion.

The aim of this study was to investigate techniques for assessment of surgical procedures for foot disorders. An optoelectronic system was used to obtain position data during walking for the knee joint, ankle joint and the second metatarsal joint. The ground reaction forces were simultaneously measured and the moment of force at the mentioned joints were analysed. Pressure transducers in the shoe were used to measure the local pressure at the great toe, first and fifth metatarsal heads, and heel pad. Among studied procedures were Keller's operation for hallux rigidus and distal oblique osteotomy for hallux valgus. The study indicated that both methods can be used to assess mediolateral shifts of the centre of pressure on the foot due to the operation. A difference between operation results were that the moment arm of the ground reaction force with respect to the knee joint increased after distal oblique osteotomy, while it decreased after the Keller type operation. From a clinical point of view this can have the effect that the loads at the knee joint and especially at the medial condyle increases after the distal oblique osteotomy. The study showed that the described techniques have a potential for assessment of surgery for first metatarsophalangeal joint. Of special relevance is the possibility of studying the effect of foot pathologies on the loads at the knee joint.