[The significance of inflammatory changes in the tarsometatarsal joints for development of rheumatic splayed foot: a radiologic follow-up].

The involvement of foot joints is a common finding in more than 90% of the patients with rheumatoid arthritis. The typical deformity of the forefoot is the splayfoot with hallux valgus or hallux rigidus and deformities of the lesser toes. 70 feet of 36 patients with rheumatoid arthritis were observed radiologically over a period between 5 years/1 month and 6 years/1 month. The x-rays were analyzed for arthritic changes of the various joints and changes of the foot statics. The question was whether the splay of the forefoot is caused by an arthritis of the metatarsophalangeal or tarsometatarsal joints with a consequent weakening of joint capsules and ligaments, or statistically by a flattening of the longitudinal arch owing to arthritic changes of the hindfoot. The statistic analysis showed that the splay of the forefoot appears between the first and second metatarsal bones. The arthritis of the tarsometatarsal joints II-IV could be identified as a statistically significant factor for the development of a splayfoot in rheumatoid arthritis. The influence of arthritic changes of the tarsometatarsal joints I and V was striking, but not statistically significant. The arthritis of the tarsometatarsal joints caused a flattening of the transverse arch already at an early stage. An arthritis of the metatarsophalangeal joints and the flattening of the longitudinal arch with arthritides of the rear foot had no statistically significant influence on the forefoot. From the results, we must draw the conclusions that orthopedic aids like shoe supports with retrocapital metatarsal bars should be recommended already at an early stage of the disease and that the support of the longitudinal arch is not sufficient to prevent a splayfoot.