The clinical trajectory of people with knee osteoarthritis: secondary analysis of a follow-up assessment following a two-year supplemental intervention

To report the clinical trajectory of physical function in people with knee osteoarthritis (OA) four years following a two-year daily intervention involving daily glucosamine and chondroitin sulfate supplements. Secondary objective is to determine if baseline patellofemoral OA features identified on magnetic resonance imaging (MRI) at baseline predict changes in physical function, pain and quality of life two and four years following a supplement intervention.