Knee injury and Osteoarthritis Outcome Score (KOOS) scales were valid and responsive in a recent study that examined a cohort (n=1,143) of US total knee replacement (TKR) patients. KOOS quality of life (QOL) performed particularly well in capturing aggregate knee-specific outcomes. Pre-TKR and 6-month post-TKR data from patients was used to compare the KOOS, Western Ontario and McMaster Universities Arthritis Index (WOMAC), and Short Form (SF-36) Health Survey. Researchers found:

• In support of convergent and discriminant validity, KOOS scale scores were worse for patients using an assistive device but only declined weakly with increasing comorbid conditions.
• While all knee-specific scales discriminated between better, same, or worse (BSW) groups, the KOOS QOL scale was significantly better than all measures except the SF-36 Physical Component Summary.
• KOOS Pain and Symptoms scales discriminated better than WOMAC Pain and Stiffness scales among BSW groups.