Immobilization of the ankle using a walking cast or boot is a common treatment to relieve pain. When walking with a walking cast or boot, the ankle joint still bears compressive load, but is limited in its ability to move. The use of this intervention suggests that pain may be exacerbated by the interaction of compression and movement and that other interventions that reduce or eliminate movement may also be effective at reducing pain. Unfortunately, the use of walking casts or boots reduce the need for muscular contractions across the ankle joint, leading to atrophy and weakness of the leg muscles. Walking casts and boots are also highly noticeable interventions that may negatively affect patient compliance. Recent work has shown that rocker shoes can be manufactured that lead to little or no motion at the ankle during single limb support (SLS) phase of walking, the period of highest compressive load on the joints. These rocker shoes lead to "natural immobilization" of the ankle joint because they provide a rocker shape that able- bodied persons consistently and naturally try to obtain during level walking. Muscle activity is still needed to "naturally immobilize" the ankle with rocker shoe, suggesting that long term use of the shoes may not lead to muscle atrophy. This pilot study includes development of rocker shoes that can "naturally immobilize" the ankle during single limb support of walking and a comparison of these rocker shoes with a walking boot. The study will contain parallel groups of persons with constant chronic ankle pain for whom walking boots are being considered as an approach to reduce pain. One group (n = 15) will use rocker shoes that "naturally immobilize" the ankle during SLS, while the second group (n = 15) will use a walking boot to immobilize the ankle. Both groups will use the interventions over a two month period of time and data will be acquired before and after the intervention focusing on pain relief, calf circumference (to reflect muscle atrophy), usage times, and patient satisfaction.
Arthritis is the leading cause of disability in the US. Approximately 15% of community-dwelling persons over age 65 have chronic pain in the foot and ankle, including many Vietnam veterans. While rheumatoid arthritis (RA) and osteoarthritis (OA) are largely age and use related, osteoarthritis can result from injury at any age and produce chronic pain, the incidence of which would be greater in populations that have been highly active, such as veterans. Osteoarthritis of the ankle in particular affects between 1-4% of the adult population and the incidence of post traumatic ankle osteoarthritis has risen in recent years. Rocker shoes that "naturally immobilize" the ankle during the single limb support phase of walking may reduce pain without negative effects of complete immobilization in a walking boot (e.g. muscle atrophy). Successful development and testing of these rocker shoes could lead to pain relief in many veterans with foot and ankle pain.