A new study from the University of Southampton has found that certain bone marrow lesions can help identify patients who are likely to suffer from rapidly progressing osteoarthritis (OA).  

OA results from damage to articular cartilage induced by a complex interplay of genetic, metabolic, biochemical, and biomechanical factors with secondary components of inflammation. The process involves interactive degradation and repair processes of cartilage, bone, and synovium. It is widely believed that in most patients, the initiating mechanism is damage to normal articular cartilage by physical force. Chondrocytes react to this injury by releasing degradative enzymes and by elaborating inadequate repair responses.

The SEKOIA (Strontium Ranelate in Knee Osteoarthritis) study is an international, multicenter, randomized, double-blind trial in outpatients with knee OA conducted in 98 centers in 18 countries. The selection criteria defined eligible patients as white, ambulatory men and women aged ≥50 years with knee OA according to American College of Rheumatology criteria with pain on at least half of the days of the previous month (intensity ≥40 mm on a 100-mm visual analog scale).  A total of 559 men and women fulfilling these criteria were followed for an average of 3 years with serial knee radiographs, with a subset of these patients receiving serial knee magnetic resonance imaging (MRI) examinations.  Kellgren and Lawrence (KL) grades to measure the presence of typical features of OA were assigned to patients by looking at joint space narrowing, presence of osteophytes, and evidence of bone sclerosis.

 Bone marrow lesions (BMLs) associated with OA appear as areas of bone located beneath arthritic cartilage with evidence of edema, fibrosis, and necrosis.  Individuals with MRI-detected BMLs at the tibiofemoral joint at baseline were found to have a significantly higher rate of annual change in joint space width. This difference persisted even after adjusting for differences in age, sex, and baseline KL grade.  Individuals with BMLs on initial knee MRI scans had OA that progressed at an average rate of 0.15 mm/y as compared to a rate of 0.10 mm/y in patients with no BML on initial MRI scans.  This study highlights a potential early indicator of rapidly progressing knee OA that may help guide early treatment and intervention. It also underscores the need for further study into the mechanisms by which bone marrow lesions are affecting the rates of progression of OA and the possibility for new therapeutic interventions.

Reference

Edwards MH, Parsons C, Bruyère O, et al; the SEKOIA Study Group. High Kellgren-Lawrence grade and bone marrow lesions predict worsening rates of radiographic joint space narrowing: the SEKOIA study. J Rheumatol. 2016; Jan 15. pii: jrheum.150053. [Epub ahead of print]