Cross-cultural adaptation and determination of the reliability and validity of PRTEE-S (Patientskattad Utvardering av Tennisarmbage), a questionnaire for patients with lateral epicondylalgia, in a Swedish population

Background: In Sweden, as well as in Scandinavia, there is no easy way to evaluate patients' difficulties when they suffer from lateral epicondylitis/epicondylalgia. However, there is a Canadian questionnaire, in English, that could make the evaluation of a patient's pain and functional loss both quick and inexpensive. Therefore, the aim of this study was to translate and cross-culturally adapt the questionnaire Patient-rated Tennis Elbow Evaluation into Swedish ( PRTEE-S; Patientskattad Utvardering av Tennisarmbage), and to evaluate the reliability and validity of the test. Methods: The Patient-rated Tennis Elbow Evaluation was cross-culturally adapted for the Swedish language according to well-established guidelines. Fifty-four patients with unilateral epicondylitis/ epicondylalgia were assessed using the PRTEE-S ( Patientskattad Utvardering av Tennisarmbage), the Disabilities of Arm, Shoulder, and Hand questionnaire, and the Roles & Maudsley score to establish the validity and reliability of the PRTEE-S. Reliability was determined via calculation of the intra-class correlation coefficient (ICC) the internal consistency was assessed by Cronbach'salpha, and validity was calculated using Spearman's correlation coefficient. Results: The test-retest reliability, using the PRTEE-S ( Patientskattad Utvardering av Tennisarmbage) intraclass correlation coefficient, was 0.95 and the internal consistency was 0.94. The PRTEE-S correlated well with the Disabilities of the Arm, Shoulder, and Hand questionnaire ( r = 0.88) and the Roles & Maudsley score ( r = 0.78). Conclusion: The PRTEE- S ( Patientskattad Utvardering av Tennisarmbage) represents a reliable and valid instrument to evaluate the subjective outcome in Swedish speaking patients with lateral epicondylitis/ epicondylalgia, and can be used in both research and clinical settings.