Effect of elbow position on grip strength in the evaluation of lateral epicondylitis.

Purpose: This study evaluated the maximum grip strength in a position of elbow extension versus flexion as a diagnostic tool in the assessment of a patient with suspected lateral epicondylitis (LE).

Methods: From our database we identified 81 patients with grip strength measurements and the diagnosis of LE. From these patient records we collected grip strength measurements with the elbow in full extension and with the elbow in 90 degrees of flexion for the affected and the healthy extremity. We then compared 2 values: the pretreatment grip strength in flexion and extension for the affected extremity and the pretreatment grip strengths of the nonaffected extremity compared with the affected extremity. Grip strengths were compared with paired and unpaired 2-tailed t tests.

Results: Grip strength was no different in flexion and extension for the healthy extremity and 29% stronger in flexion than in extension for the affected extremity. The affected arm averaged 50% of the strength of the healthy arm in extension and 69% of the strength of the healthy arm in flexion. These differences were statistically significant. An 8% difference in grip strength between flexion and extension was found to be 83% accurate in distinguishing the affected from the unaffected extremities.

Conclusions: The measurement of extension grip strength is a useful objective tool to aid in the diagnosis of LE. In patients with LE, the grip strength decreases as one moves from a position of flexion to a position of extension.