Responsiveness and interpretability of the pain subscale of the Knee and Hip Osteoarthritis Outcome Scale (KOOS and HOOS) in osteoarthritis patients according to COSMIN guidelines.

This study endorses the responsiveness of the KOOS and HOOS pain subscales in patients with knee or hip OA and patients after TKA and THA based on construct and criterion validity approaches. The KOOS pain subscale might be able to detect the MIC at an individual level after arthroplasty, but both the KOOS and HOOS pain subscales were not able to do so after conservative treatment. This study is the first to report a considerable response shift in MIC of the KOOS and HOOS pain subscales. This should be taken into consideration when evaluating MIC of the KOOS and HOOS pain subscale after conservative versus operative treatment. Future research should present more reference data regarding MIC scores after different treatments.