Pelletier JP et al. (2007) Risk factors associated with the loss of cartilage volume on weight-bearing areas in knee osteoarthritis patients assessed by quantitative magnetic resonance imaging: a longitudinal study. Arthritis Res Ther [doi: 10.1186/ar2272]

Researchers from North America have investigated the risk factors associated with progression of knee osteoarthritis (OA) by using MRI to quantitatively assess the progressive loss of cartilage volume in different areas of the knee and studying the correlation of these changes with demographic, clinical, radiological, and structural variables. This longitudinal study included a subset of 107 patients with symptomatic knee OA selected from a larger trial assessing the effects of bisphosphonate therapy. Patients were evaluated at baseline and at 24 months with X-ray and MRI investigations of the knee.

The analysis revealed that the greatest percentage of cartilage volume loss over the 24-month period occurred in the medial condyle and plateau, followed by the lateral plateau and the trochlear area. In general, the central weight-bearing subregions were worst affected. The loss of cartilage at 24 months compared with baseline was significant for all subregions apart from the anterior and posterior portions of the lateral condyle and anterior portion of the tibial plateau (P <0.0001).

Patients at greatest risk of cartilage loss, particularly in the medial compartment, tended to be female, to have a higher BMI, and to have a narrower joint space width. The most significant structural risk factors were severe medial meniscal tear or extrusion, and subchondral bone marrow hypersignal.

The authors conclude that their findings shed light on the natural history of knee OA, the evolution of symptoms, and the risk factors associated with cartilage loss.