The Effect of Elbow and Forearm Position on the Resisted Wrist Extension Test and Incidence of Sensory Disturbance of the Superficial Radial Nerve in Patients with Lateral Epicondylitis.

Abstract

Background: The aim of this study is to determine the effect of elbow and forearm position on the resisted wrist extension test (RWET) in patients with lateral epicondylitis. We also looked at the incidence of associated sensory disturbance of the superficial radial nerve (SRN) and the effect of treatment of lateral epicondylitis on sensory disturbance. Methods: Sixty-three consecutive patients (68 limbs) with lateral epicondylitis and an equal number of age and gender matched volunteers were investigated. Patients with lateral epicondylitis were subdivided into two groups based on history of corticosteroid injection. We performed the RWET in four limb positions namely elbow extended and forearm pronated (EP), elbow flexed and forearm pronated (FP), elbow extended and forearm supinated (ES), elbow flexed and forearm supinated (FS). Sensory disturbance in the SRN was assessed using a Wartenberg pin wheel. Results: The positivity rate of the RWET was significantly higher in the EP position (100%) compared to the FP (66%), ES (62%) and the FS (24%) positions in limbs with lateral epicondylitis. The RWET was positive only in one subject in the EP position in the control group (1.5%). Sensory disturbance in the SRN territory was present in 63.2% of limbs and only two subjects (2.9%) in the control group. The incidence of sensory disturbance was significantly higher (74.5% vs. 48.3%, p < 0.05) in patients who did not have a corticosteroid injection. Conclusions: The sensitivity and specificity of the RWET is better when it is performed with the elbow in extension with the forearm pronated (EP); 63.2% of limbs with lateral epicondylitis were noted to have an associated sensory disturbance of the SRN and a corticosteroid injection seems to decrease the incidence of sensory disturbances. Level of Evidence: Level II (Diagnostic).