The aim of the study was to evaluate the correlations between clinical symptoms (pain), physical examination, ultrasound (US), and radiological findings in patients with bilateral knee osteoarthritis (OA).
Knee pain was appreciated during medial and lateral palpation of each knee joint and using visual analogue scale (VAS) and The Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). US evaluation (osteophytes, meniscal protrusion, synovial fluid, femoral hyaline cartilage thickness) and radiological assessment (osteophytes, femoral-tibial space, Kellgren-Lawrence [K-L] score, enthesopathies) were performed by two examiners blinded to the clinical results and to each other. All these findings were scored with a five-point scale.
A total of 52 consecutive patients aged 63.44+/-9.49 were examined, 33 (80.5%) being females. In patients with bilateral knee OA the pain, evaluated by WOMAC score and VAS, was correlated with the presence of osteophytes and cartilage thickness but no association with medial meniscal protrusion and effusion was demonstrated. Pain produced by palpation of the knee was strongly associated with the presence of medial osteophytes. VAS and WOMAC scores increased with the severity of radiological and US findings. The presence of osteophytes and articular cartilage damage at US examination were strongly and positively correlated with radiological K-L score. US examiners agreement was good for osteophytes and moderate for meniscal protrusion, cartilage damage, and synovial fluid. The cartilage damage score was the only independent predictor for VAS scale; for WOMAC score the sex, cartilage damage, the presence of medial osteophytes and lateral meniscal protrusion were the independent predictors.
Pain intensity was correlated with the severity of US findings, cartilage damage score being an independent predictor for both VAS and WOMAC scores. Medial osteophytes and lateral meniscal protrusion and are independent predictors for WOMAC score.