Cross-cultural adaptation and validation of the Filipino translation of the knee injury and osteoarthritis outcome score in Filipinos with knee osteoarthritis at a tertiary hospital

ABSTRACT

Objectives@#1) To translate and cross-culturally adapt the Knee Injury and Osteoarthritis Outcome Score (KOOS) into Filipino; 2) To validate the Filipino translation of KOOS using the Filipino Short-Form 36 Health Survey (SF-36) among patients with knee osteoarthritis (kOA) at a tertiary hospital. @*Methodology@#A Filipino version of the KOOS was translated and cross-culturally adapted from the original English version and validated following standard guidelines. Adult Fiipino patients with knee osteoarthritis at the University of the Phiippines-Philippine General Hospital were asked to complete identical questionnaires containing the Filipino KOOS and Filipino SF-36, with re-test on the same patients after a median of 14 days. Reliability was assessed using Cronbach’s alpha and intraclass correlation coefficients (ICC); dimensionality using convergent and divergent construct validity. @*Results@#The Filipino translation of the KOOS was administered to 30 patients with knee OA (kOA). Cronbach's α across the Filipino KOOS domains ranged from 0.71 to 0.89 suggesting good internal consistency. The reproducibility of measurements of all KOOS subscales by ICC ranged from 0.97 to 1.0. For convergent construct validity, there was moderate correlation between KOOS ADL (0.38, p =0.03) and knee-related QoL (0.42, p=0.02) by SF-36 Physical Functioning (PF). A strong correlation (0.51, p=0.003) was observed between KOOS sports and recreation domain with SF-36 PF. For divergent construct validity, there was weak correlation between KOOS pain (0.015, p=0.93) and symptoms (0.15, p=0.42) with SF 36 Social Functioning. @*Conclusion@#The Filipino version of the KOOS is a valid and reliable instrument to measure the different aspects of disability affecting quality of life of Filipino patients with kOA.