Polish Cross-Cultural Adaptation and Validation of the Knee Outcome Survey Activities of Daily Living Scale (KOS-ADLS) in Patients Undergoing Total Knee Arthroplasty

BACKGROUND: The Knee Outcome Survey Activities of Daily Living Scale (KOS-ADLS) is a self-reported questionnaire used for the evaluation of the overall health of patients with knee dysfunctions. The purpose of this study was to perform a cross-cultural adaptation of the Polish version of KOS-ADLS and to evaluate its psychometric properties in patients at the end-stage of knee osteoarthritis who were qualified for a total knee replacement (TKR). MATERIAL/METHODS: Seventy patients consecutively qualified for surgical TKR procedure participated in this study. To adapt the KOS-ADLS, the following scales and reference tests were used: Knee injury and Osteoarthritis Outcome Score (KOOS), Visual Analogue Scale (VAS), Time Up and Go test (TUG), and Five Times Sit to Stand test (5×STS). The studies were conducted 3 times: 2 weeks before surgery (first study), 6 to 13 days later (retest), and 6 months after surgery. RESULTS: The Polish version of KOS-ADLS showed excellent reliability (ICC=0.89 SEM=2.68, MDC=7.43) and high responsiveness (ES=4.76, SRM=3.18). The internal consistency was poor in the first assessment (Cronbach’s alpha=0.68), but acceptable in the post-surgery evaluation (Cronbach’s alpha=0.86). There were fair and moderate correlations found between KOS-ADLS and VAS scales in the first examination, TUG, and 5×STS. Stronger correlations were observed between the results obtained in KOS-ADLS and KOOS. CONCLUSIONS: The Polish version of the KOS-ADLS demonstrated good reliability, validity, and responsiveness for use in patients who have undergone TKR surgery.