Weight-bearing roentgenograms of 308 feet of rheumatoid arthritis patients were analyzed. Several angles were determined, including the metatarsus primus adductus angle (between the first and second metatarsals, > or = 10 degrees) and the forefoot spread angle (between the first and fifth metatarsals, > or = 30 degrees). Pes planus was diagnosed when the internal arch angle was equal to or greater than 130 degrees. Tarsal arthritis was defined as the presence of joint space narrowing. Varus of the first metatarsal was correlated with tarsal arthritis and pes planus but not with duration of the disease. Forefoot spread was correlated with duration of the disease and erosive metatarsal disease but not with involvement of the midfoot. These data demonstrate that orthopedic treatment should be initiated as soon as involvement of the first metatarsal is detected and should be directed at the hindfoot, midfoot, and first metatarsal whose deformations occur concomitantly.