Has the median nerve involvement in rheumatoid arthritis been overemphasized?

Rheumatoid arthritis (RA) is a well and widely recognised cause of carpal tunnel syndrome (CTS). In the rheumatoid wrist, synovial expansion, joint erosions and ligamentous laxity result in compression of the median nerve due to increased intracarpal pressure. We evaluated the published studies to determine the prevalence of CTS and the characteristics of the median nerve in RA and its association with clinical parameters such as disease activity, disease duration and seropositivity. A total of 13 studies met the eligibility criteria. Pooled data from 8 studies with random selection of RA patients revealed that 86 out of 1561 (5.5%) subjects had CTS. Subclinical CTS, on the other hand, had a pooled prevalence of 14.0% (30/215). The cross sectional area of the median nerve of the RA patients without CTS were similar to the healthy controls. The vast majority of the studies (8/13) disclosed no significant relationship between the median nerve findings and the clinical or laboratory parameters in RA. The link between RA and the median nerve abnormalities has been overemphasized throughout the literature. The prevalence of CTS in RA is similar to the general population without any correlation between the median nerve characteristics and the clinical parameters of RA.