Relation between cartilage loss and pain in knee osteoarthritis

We read with interest the recent work in Annals of the Rheumatic Diseases by Bacon and colleagues regarding the relationship between cartilage loss and pain in patients with knee osteoarthritis (OA).1 The authors included 600 participants within the Osteoarthritis Initiative and found that cartilage loss was significantly associated with a small degree of worsening in pain over 24 months. The relation between cartilage thickness loss and pain was partially mediated by synovitis change, rather than by changes in bone marrow lesions. This finding prompted us to reconsider the relation between cartilage loss and pain, and the clinical efficacy of the chondroprotective application in the treatment of knee OA. Their excellent and important work adds to our knowledge base, but we do have two minor points that may help to contextualise findings from this study and contribute to further investigations.

First, the predominant patient population included in this...