Pathological anatomy and dynamic effect of the displaced plantar plate and the importance of the integrity of the plantar plate-deep transverse metatarsal ligament tie-bar.

Normal and deformed forefeet have been investigated by cadaver anatomical dissections and experiments, by radiographs, CT and MRI scanning, and by clinical studies. Evidence is presented to show that the skeleton of the foot rests on and is controlled by a multi-segmental ligamentous and fascial tie-bar system. Transversely across the plantar aspect of the forefoot, the plantar plates and the deep transverse metatarsal ligaments form a strong ligamentous structure which prevents undue splaying of the forefoot. Longitudinally, the five digital processes of the deeper layer of the plantar fascia are inserted into the plantar plates and control the longitudinal arch of the foot. It is suggested that many forefoot deformities result from the failure of parts of the tie-bar system and the dynamic effect of displacement of the plantar plates. Understanding this allows a more logical approach to their treatment.