Rigid Hindfoot Orthosis Helps Ankle Arthritis
In this study, researchers compare different ankle-foot orthoses (AFO) used by patients with subtalar osteoarthritis (OA). The subtalar joint is part of the ankle. It is located just above the calcaneus (heel bone) where the talus bone meets the calcaneus.

AFOs are a type of brace made from a rigid polypropylene (plastic). The goal is to limit hindfoot motion thereby reducing pain and improving stability. They are especially helpful for walking over uneven surfaces.

Ten patients with subtalar OA were included. Three types of AFOs were used: rigid AFO, rigid hindfoot orthosis (HFO-R) and articulated hindfoot orthosis (HFO-A). The rigid AFO supports the back of the calf down to the base of the toes. The HFO-R starts midcalf and includes the ankle but not the foot or toes. The HFO-A starts midcalf, has a hinge joint at the ankle, and goes to the base of the toes.

Patients were filmed walking over level ground, up and down a ramp, and on two types of slopes. Tests were also done in standard shoes without the orthoses. A special computer program analyzed the three-dimensional movement. Angles of motion of the hindfoot were calculated.

The results showed that none of the orthoses kept the hindfoot from moving all the time. Motion was certainly less with an orthotic compared to without it. The HFO-R did the best job holding the hindfoot stable while still allowing motion in the forefoot.

The authors conclude patients with pain and stiffness from subtalar OA should try the HFO-R orthotic. Besides reducing pain, it may also improve step and stride length. The patient may be able to walk longer distances with less fatigue.
Yu-Chi Huang, MD, et al. Effects of Ankle-Foot Orthoses on Ankle and Foot Kinematics in Patients with Subtalar Osteoarthritis. In Archives of Physical Medicine and Rehabilitation. August 2006. Vol. 87. No. 8. Pp. 1131-1136.