Cross-cultural adaption, translation and validation of the Toronto extremity salvage score (TESS) for patients in German-speaking countries

Abstract

Summary Objective The preferred treatment for malignant bone and soft tissue tumors is limb salvage surgery; the Toronto extremity salvage score (TESS) is commonly used to measure physical functioning of the affected extremity. The aims of this study were to translate and culturally adapt the German version of the TESS, as well as to explore its convergent reliability, validity and re-test reliability. Study design Patients (n = 50) 32 lower extremity (LE) and 18 upper extremity (UE) were asked to fill out the German TESS two times (t1: clinical visit, t2: regular email) and the SF-36 once. Methods The TESS questionnaires were translated from English into German, back translated into English, and culturally adapted. The reliability was assessed with Cronbach’s alpha (α). The validity was measured with the SF-36 physical component score and TESS using the Spearman rank correlation coefficient (r). Furthermore, the test-retest reliability was calculated with the intraclass correlation coefficient (ICC). Results Internal consistency for both questionnaires was excellent (LE t1: α = 0.924, t2: α = 0.952; UE t1: α = 0.957, t2: α = 0.898). A statistically significant correlation was found between the SF-36 physical component scale and the German TESS (LE r = 0.741, UE r = 0.713). The ICC between baseline (t1) and re-test (t2) was 0.952 and 0.871 for the lower and upper extremities, respectively. Conclusion Initial evidence demonstrated that the German TESS is a valid and reliable instrument for use with patients after surgical treatment of malignant bone or soft tissue sarcoma.