Prevalence and the Influence of Trapeziometacarpal Osteoarthritis on Patients with Carpal Tunnel Syndrome.

Background: The coexistence of carpal tunnel syndrome (CTS) and trapeziometacarpal (TMC) osteoarthritis have been previously described. The influence of TMC osteoarthritis in the outcomes of CTS surgery is yet to be elucidated. The purpose of this study is to examine the prevalence of TMC osteoarthritis in patients who underwent open carpal tunnel release (OCTR) and to analyse the influence of osteoarthritis on the postoperative outcomes of CTS. Methods: We retrospectively reviewed 134 procedures on 113 patients who underwent OCTR between 2002 and 2017. The presence of TMC osteoarthritis was based upon preoperative plain radiograph. For the evaluation of CTS, pre- and postoperative muscle power of abductor pollicis brevis (APB) muscle by manual muscle testing (MMT) and distal motor latency (DML) detected on the APB muscle was examined. Results: The mean follow-up period was 11.4 months. The prevalence of radiographic TMC osteoarthritis was 40% in patients who underwent OCTR. In electrophysiological study, the mean pre- and postoperative DML showed no statistical difference regardless of the coexistence of TMC osteoarthritis. However, there was a significantly higher incidence of poorer muscle strength of the APB in patients with TMC osteoarthritis. No patients complained of TMC joint pain prior to OCTR, but four cases developed TMC joint pain during the postoperative follow-up period, all of whom had full recovery of APB muscle strength. Conclusions: The presence of asymptomatic TMC osteoarthritis may affect the postoperative outcomes of OCTR, so preoperative evaluation of TMC osteoarthritis should be considered in patients undergoing OCTR. In addition, the symptoms of TMC osteoarthritis may worsen in some patients after CTS surgery and should be taken into consideration during the postoperative follow-up. Level of Evidence: Level IV (Therapeutic).