In Vivo Forces in the Plantar Fascia During the Stance Phase of Gait

Abstract

Plantar fasciotomies have become commonplace in podiatric and orthopedic medicine for the treatment of plantar fasciitis. However, several complications have been associated with plantar fascial release. It has been speculated that the cause of these complications is excessive release of the plantar fascia. The aim of this project was to determine whether the amount of fascia released, from medial to lateral, causes a significant increase in force in the remaining fascia. A dynamic loading system was developed that allowed a cadaveric specimen to replicate the stance phase of gait. The system was capable of applying appropriate muscle forces to the extrinsic tendons on the foot and replicating the in vivo timing of the muscle activity while applying force to the tibia and fibula from heel strike to toe-off. As the plantar fascia was sequentially released from medial to lateral, from intact to 33% released to 66% released, the real-time force and the duration of force in the remaining fascia increased significantly, and the force was shifted later in propulsion. In addition, the subtalar joint was unable to resupinate as the amount of fascia release increased, indicating a direct relationship between the medial band of the plantar fascia and resupination of the subtalar joint during late midstance and propulsion. (J Am Podiatr Med Assoc 93(6): 429-442, 2003)