Comparison of Ultrasonographic and Radiographic Findings in Knee Osteoarthritis: A Cross-sectional Study
TL;DR
USG provides improved detection of osteophytes and offers additional information on soft-tissue and early structural changes in knee OA and serves as a valuable, accessible adjunct to conventional radiography for comprehensive evaluation and early diagnosis of knee OA.
Abstract
Introduction: Knee Osteoarthritis (OA) is a prevalent degenerative joint disorder and a major cause of pain and disability among the elderly population. Conventional radiography remains the standard imaging modality for diagnosis and grading; however, it has limited sensitivity in detecting early and soft-tissue changes. Ultrasonography (USG) has emerged as a useful, cost-effective adjunct for evaluating both osseous and periarticular soft-tissue abnormalities. Hence, there is a need to assess its diagnostic efficacy in comparison with radiography. Aim: To compare the ultrasonographic features with radiographic grading (Kellgren-Lawrence) in patients with knee OA. Materials and Methods: The present cross-sectional observational study was conducted in the Department of Orthopaedics at SRM Medical College Hospital and Research Institute, Kattankulathur, Chennai, Tamil Nadu, India. from May 2024 to August 2024. A total of 48 patients aged above 50 years fulfilling the American College of Rheumatology (ACR) criteria for knee OA were included. All patients underwent standing anteroposterior and lateral radiographs, graded using the Kellgren-Lawrence (KL) classification, followed by ultrasonographic evaluation using a high-frequency linear probe. Parameters studied included osteophytes, Joint Space Narrowing (JSN), cartilage thickness, joint effusion, Baker’s cyst, and meniscal protrusion. Statistical analysis was performed using Statistical Package for Social Sciences (SPSS) software (version 22.0). McNemar’s test, Chi-square test, and paired t-test were applied. A p-value of <0.05 was considered statistically significant. Results: The majority of patients were aged 60-69 years 20 (41.7%) with a female predominance 26 (54.2%). Most cases belonged to Kellgren-Lawrence (KL) Grade 2 18 (37.5%) and Grade 3 16 (33.3%). USG detected osteophytes in 44 (91.7%) of patients compared to 34 (70.8%) on radiography (p=0.004). JSN was observed in 38 (79.2%) by USG and 36 (75.0%) by radiography (p=0.62), showing no significant difference. Ultrasonographic findings such as reduced cartilage thickness 32 (66.7%), joint effusion 20 (41.7%), and meniscal protrusion 12 (25.0%) increased significantly with higher KL grades (p<0.05). Mean medial joint space measurements were comparable between modalities (p=0.48), whereas USG detected significantly reduced lateral joint space compared to radiography (p=0.03). Conclusion: USG provides improved detection of osteophytes and offers additional information on soft-tissue and early structural changes in knee OA. It associates well with radiographic severity and serves as a valuable, accessible adjunct to conventional radiography for comprehensive evaluation and early diagnosis of knee OA.
