RHEUMATOID ARTHRITIS

Rheumatoid arthritis often gives rise to painful collapse or partial collapse of the foot into valgus under load-bearing conditions, limiting the subject's ability to walk. However, the ankle joint frequently remains unimpaired. Thus, in serious cases a cosmetic splint is required which supports the foot whilst allowing the ankle to plantarflex and dorsiflex. The Cherwell ankle-foot orthosis has been designed and extensively tested in Oxford and elsewhere during the last four years, and can now be prescribed and supplied from three orthopaedic centres to meet this requirement. KEY WORDS: Rheumatoid arthritis, Orthotics, Ankle, Foot. DAMAGE to the metatarsophalangeal joints is very common in patients with rheumatoid arthritis and its treatment, whether by conservative or operative methods, well established (1). Although symptoms and radiological evidence of disease are less frequent in the more proximal foot and in the ankle joints, the almost universal tendency for damaged mid-tarsal and sub-talar rheumatoid joints to collapse into valgus under load, means that stand-ing and walking are painful in approximately half the patients (2). The size of the problem has been estimated (3) and it is possible that up to 1 % of the population could require some form of mid- or hind-foot support. In the early stages of the condition, the arches of the foot can be maintained, and pressure points can be relieved by insoles and other adaptations to the shoes. Rigid insoles and shoe modifications can also change the line of force through the foot and thereby reduce pain and instability. As the disease develops, some feet remain fully or partially mobile, but walking becomes extremely painful. Insoles and corrected shoes are inadequate, and the patient's daily activities become restricted. The disease may, however, take another course, with the foot becoming deformed and rigid, so that special footwear is necessary. To meet the need for conservative treatment of painful valgus feet, the Cherwell cosmetic orthosis was designed and developed in 1978. Since that time it has undergone extensive field trials in Oxford and elsewhere