Intraarticular and plantar pressure distribution in the ankle joint complex with various foot positions

Ankle injuries are often followed by degenerative changes in the hindfoot j oints. Knowledge about the pressure distribution of the intact ankle joint may help to understand the mechanisms leading to cartilage damage. Therefor e, we determined the intraarticular and plantar pressure distribution of th e ankle joint complex and the Chopart joints with varying foot positions. 12 human lower leg specimens were axially loaded in a foot-loading simulato r with full body weight (600 N). A capacitive pressure distribution platfor m was used to determine plantar pressure patterns. The intraarticular loadi ng situation was measured with Fuji Prescale film. 3 different foot positio ns (neutral, 10 degrees dorsiflexion, 10 degrees plantarflexion) were inves tigated. Dorsiflexion led to an increase of the intraarticular contact area, force a nd mean pressure in the hindfoot. Plantarflexion instead increased loading in the Chopart joints. In the plantar pressure distribution force and peak pressure under the hindfoot increased with dorsiflexion. With plantarflexio n area, force and peak pressure under mid- and forefoot increased. With our study we could demonstrate that the loading situation of the ankle joint complex is significantly influenced by the foot position. These find ings may help to understand the development and localisation of arthritic c hanges due to posttraumatic changes of the joint loading characteristics.