Association Between Change in Scores of Knee Injury and Osteoarthritis Outcome Score-12 (KOOS-12) and Global Rating of Change Scale in Knee Osteoarthritis Patients

Background: Knee osteoarthritis (KOA) is the most prevalent form of osteoarthritis, contributing significantly to disability among older adults. Patient-reported outcome measures such as the Knee injury and Osteoarthritis Outcome Score-12 (KOOS-12) and global anchors like the Global Rating of Change Scale (GRCS) are widely employed to assess treatment response, but their alignment in physiotherapy-managed KOA remains uncertain. Objective: To evaluate the association between changes in KOOS-12 subscale scores (pain, function, quality of life) and GRCS ratings in patients with KOA undergoing physiotherapy. Methods: A prospective cohort study was conducted at Medicure Hospital, Lahore, including 60 patients aged 50–65 years with Kellgren–Lawrence grade II–III KOA. Participants completed KOOS-12 and GRCS questionnaires at baseline and at 4, 8, and 12 weeks of physiotherapy. Changes in KOOS-12 subscale scores were correlated with GRCS using Spearman’s rank correlation. Statistical analyses were performed with SPSS version 23, with p < 0.05 considered significant. Results: The mean age was 58.4 ± 4.15 years, and mean BMI was 30.6 ± 5.16 kg/m². Females comprised 58.3% of participants. Correlations between KOOS-12 changes and GRCS were weak: pain (rho = 0.15, p = 0.252), function (rho = 0.12, p = 0.375), and quality of life (rho = 0.11, p = 0.395). Conclusion: KOOS-12 subscales demonstrated only weak associations with patient-perceived improvement on GRCS, suggesting that multidimensional outcome assessment is essential for evaluating physiotherapy response in KOA.