Correlation between MRI and conventional radiographic findings in evaluation of osteoarthritis.

Objective: To evaluate the diagnostic accuracy of X-rays in detecting osteoarthritis (OA) in comparison to MRI. Study Design: Cross-sectional study. Setting: The Fauji Foundation Hospital, Rawalpindi. Period: August, 2023 to March, 2024. Methods: Total 350 patients consented to clinical interviews, physical examinations, standing radiographs, and MRIs. Standing, semi-flexed posteroanterior radiographs of the knees were obtained with proper alignment to accurately detect joint space narrowing. Manual measurements of joint space width were conducted by a blinded orthopedic surgeon using the Kellgren-Lawrence grading system. Data analysis was performed using SPSS 23, with frequencies, percentages, means, and standard deviations calculated for relevant variables. Diagnostic accuracy was assessed using a 2x2 table. Results: Of the 350 patients, 61.1% were up to 60 years old, and 38.9% were over 60 years old. Among those with positive MRI results, 70.1% also had a positive X-ray, while 29.6% did not. Cohen's Kappa was 0.377, indicating fair to moderate agreement. Sensitivity was 54.3%, specificity 82.4%, positive predictive value 70.1%, and negative predictive value 70.4%, with an overall diagnostic accuracy of 70.3%. Conclusion: X-rays demonstrated high specificity and moderate predictive values, but low sensitivity, suggesting that some OA cases may be missed if relying solely on X-rays.