Evaluation of clinical symptoms and sonographic characteristics of femoral trochlear cartilage in primary knee osteoarthritis

Objective: This study was designed to evaluate the clinical symptoms and sonographic characteristics of femoral trochlear cartilage in patients with knee joint osteoarthritis (OA). Methods: This cross-sectional study was conducted on 94 patients with painful primary knee OA according to the American College of Rheumatology criteria with a visual analog scale pain score of 30 mm or more. Clinical features were evaluated by a rheumatologist according to the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) criteria, and a radiologist performed ultrasonography within a week. The thickness and echogenicity grade of three cartilage regions were evaluated. Other findings such as meniscal extrusion, effusion, and Baker’s cyst were recorded. Results: The average age of patients was 60 years. The linear regression model showed a significant association of grades II and III trochlear cartilage injury with the pain index, physical activity, and WOMAC overall index. However, there was no significant association between the trochlear cartilage thickness in these three regions and the WOMAC indexes (including pain, physical activity, and the overall index). There was also no significant association between Baker’s cyst and the WOMAC indexes, but a significant association was found between meniscal extrusion and the WOMAC index (P≤0.001). Conclusion: According to our study, the echogenicity grade determined by ultrasonography of femoral trochlear cartilage affects the clinical symptoms of patients including pain. These findings indicate the role of this diagnostic device in understanding changes due to the disease, and it can help physicians focus on the pathology in order to control clinical symptoms in patients.