Prevalence of the tarsal tunnel syndrome in rheumatoid arthritis.
Forty-eight patients with definite of classical rheumatoid arthritis (RA) were studied for the presence of tarsal tunnel syndrome (TTS). Nerve conduction velocities and distal latencies were determined in a constant temperature room and the findings compared with a group of 35 normal, age-matched subjects. After excluding four patients with peripheral neuropathy, a definite delay in the distal motor latency of the tibial nerve was documented in 11 subjects (25%). Two of the 11 had foot symptoms suggestive of TTS. These 11 patients with prolonged distal motor latencies did not otherwise differ from RA patients without TTS in terms of disease duration or severity, treatment, or the presence of foot deformity. Thus, compressive neuropathy of the branches of the posterior tibial nerve is a relatively frequent finding in patients with definite or classical RA.