Validity,responsiveness and reliability of the Patient-Rated Tennis Elbow Evaluation

Abstract

Introduction

Lateral epicondylitis (LE) is a common, often chronic injury that affects a person's ability to grip and perform manual tasks including activities of daily living and leisure. Treatment of LE is controversial; however, there have been no standardized tools with which to measure outcomes in trials investigating new or existing therapies for LE. The Patient-Rated Tennis Elbow Evaluation (PRTEE) was designed to fill this gap, but has not yet been validated to the same standard as other, similarly developed tools.

Methods

Sixty subjects with LE who participated in a double-blind randomized controlled trial were measured with respect to the PRTEE, ‘overall pain’, ‘resting pain’, ‘pain during sleep’, ‘pain at its worst’ and ‘pain at its least’, and quality of life. All tools were administered at baseline, four and eight weeks.

Results

The PRTEE showed poor item-specific validity with measures of similar constructs. The intraclass correlation coefficient for test–retest reliability over four weeks was 0.76. The mean PRTEE differences between the group that experienced clinical significant change and the group that experienced virtually no change were significantly different from one another (t = −2.96, df = 30, P = 0.006).

Discussion

The PRTEE shows questionable discriminant ability due to its moderate test–retest reliability and possibly due to low convergent validity with other measures of similar constructs. The PRTEE appears to be sensitive to change, but the margin of difference between a clinically relevant change and ‘no change’ is very small.