Osteoarthritis (OA) affects the hips and knees most often but can also cause ankle pain. Walking becomes very difficult because of joint pain and morning stiffness. This study reports on the use of three orthotics for ankle OA. Each one is used a little differently to control joint motion and align the foot and ankle in order to reduce pain.
The three types of ankle orthotics reviewed are: 1) solid ankle foot orthosis (AFO), 2) rigid hindfoot orthosis (HFO-R), and 3) articulated hindfoot orthosis (HFO-A). Th solid AFO covers the back of the calf, heel and bottom of the foot. No motion of the ankle or foot is allowed. The HFO-R covers the hindfoot and heel but not the toes. It prevents ankle motion but allows foot movement. The HFO-A fits across the lower calf, heel, and foot. It has a mechanical hinge joint to allow ankle motion but not foot mobility.
The orthotics were compared against each other and to a shoe without an orthosis. Patients walked over various ground surfaces. Ground conditions included a level surface, going up and down a ramp, and walking along a side-slope.
A motion analysis system was used to track the movement of ankle and foot. Each patient was tested unbraced and then with each of the orthotics on all surfaces. The authors report the HFO-R was the best choice for all surfaces. It held the hindfoot stable the best while still allowing the forefoot to move.
If ankle motion is to be restricted without affecting overall foot function, then the HFO-R is optimal when ankle OA pain is caused by ankle motion.