Relating bone marrow oedema to hs-CRP in knee osteoarthritis

ObjectiveTo study the correlation between bone marrow oedema (BME) on knee magnetic resonance imaging (MRI) and plasma high sensitive-CRP (hs-CRP) levels in patients with symptomatic osteoarthritis (OA) of the knee.MethodsThirty patients with symptomatic OA of the knee were included and stratified into three equal groups consisting of normal alignment, varus or valgus misalignment of symptomatic knee. Radiographic scoring using Kellgren-Lawrence grading (K-L grade) was performed and an MRI of the knee taken. Intensity of pain was evaluated using a pain visual analogue scale (VAS) and the functional status determined by Lequesne functional index. In addition, hs-CRP was estimated in all patients and in 20 healthy controls.ResultsBME was present in 14 patients (46%) with OA and in none of the controls. Patients with BME had significantly longer disease duration, a higher lequesne score, suggesting greater functional impairment and more advanced radiological changes. A significantly higher number of patients (12/30, 40%) had an elevated hs-CRP than healthy controls (2/20, 10%, P=0.02). There was, however, no association between hs-CRP and BME. Patients with varus and valgus deformities harboured BME on the medial and lateral tibiofemoral compartments, respectively.ConclusionBME is a feature of advanced OA of the knee and is associated with radiographic progression, a greater functional impairment and longer disease duration. It is, however, not associated with raised hs-CRP levels.