Reliability and validity of Turkish version of the patient rated tennis elbow evaluation

The objective of this study was to test the reliability of the Turkish version of PRTEE (PRTEE-T) as a specific scale for LE, and to investigate the validity of this version by correlating and comparing its outcomes with those of the scales DASH (the Disabilities of the Arm, Shoulder, and Hand questionnaire) and Quick DASH (QDASH), pain (VAS), tenderness, and maximal grip strength (MGS). Fifty patients (14 males and 36 females) with the diagnosis of lateral epicondylitis were included in this study. PRTEE Questionnaire was translated into Turkish according to the guideline for the cross-cultural adaptation process. All patients filled the PRTEE-T questionnaire. Maximal grip strength, pain, and tenderness were measured. Next, the patients filled the DASH forms. The patients were asked to reevaluate PRTEE-T 2 h after they filled the first form. The internal consistency reliability of PRTEE-T was assessed by calculating ‘if item deleted’ using Cronbach alpha and ‘Item–total correction’ coefficient for each item of the questionnaire. Consistency of subscales was assessed using Spearman’s rho correlation coefficient. In addition to correlation analysis, test–retest values were compared using Wilcoxon test to assess the changes on the basis of the items. Criterion validity of the scale was measured using DASH and QDASH scales, and construct validity was measured using tenderness and maximal grip strength values by Spearman’s rho correlation coefficient. For internal reliability; Cronbach alpha coefficient was calculated 0.837 by the overall assessment of the scale. For test–retest reliability; correlation coefficient was found 0.920 (P < 0.001). Comparison of the scores obtained from test–retest measurements showed no significant difference (P > 0.05). The pain sub-scale, the function sub-scales, and the overall score from the PRTEE-T each showed significant correlations with the DASH score (P < 0.001), QDASH score (P < 0.001), and maximal grip strength (P < 0.001). Significant correlation was found between the sub-scales of the scale. The results of our study have shown that the Turkish version of a specific and practical scale developed for LE can be both valid and reliable. PRTEE-T is easy to apply in a relatively short period and may prove to be valuable for evaluation and follow up of the patients in daily clinical practice.