Carpal tunnel syndrome in patients with rheumatoid arthritis and psoriatic arthritis: an electrophysiological and ultrasonographic study

This study aimed to investigate the carpal tunnel syndrome (CTS) in patients with rheumatoid arthritis (RA) and psoriatic arthritis (PsA), compare the electrophysiological and ultrasonographic findings and evaluate related variables. Cut-off value of median nerve cross-sectional area (MCSA) was determined for the diagnosis of CTS. 70 RA patients, 39 PsA patients, a control group of 70 healty people were included in this study. Demographic characteristics, disease activity and functional status were recorded. Patients were referred for nerve conduction studies performed according to the American Academy of Neurology standards. Sonographic examination was carried on for MCSA evaluation. The mean age of patients was 51.87 ± 8.47, 50.61 ± 11.33, 49.75 ± 10.52 years and female ratio was 72.9%, 71.8%, 75.7% in RA, PsA and controls, respectively. Electrophysiologically, CTS frequency was found to be 13.2%, 15.4%, 3.5% in RA, PsA, control group, respectively, and a significant difference was found compared to the control group (p < 0.05). Ultrasonographically MCSA was measured as 8.52 ± 2.19 mm2, 8.97 ± 2.41 mm2, 7.09 ± 1.83 mm2 in RA, PsA, control group, respectively, a significant difference was observed compared to the control group (p < 0.05). As a result of the Receiver Operating Characteristics analysis, the thereshold value of MCSA for CTS was determined as 10.5 mm2.The frequency of CTS was found to be 30% in RA and 41% in PsA. The frequency of CTS with both ENMG and USG (MCSA) were higher in patients with RA and PsA as compared to the control group. Although it was not statistically significant, CTS frequency was higher in PsA than RA. To our knowledge this is the first study assessing CTS in patients with PsA, and adressing MCSA cut off value for CTS diagnosis in RA and PsA.