DIAGNOSTIC ACCURACY OF X-RAY IN DIAGNOSING AVASCULAR FEMORAL HEAD, KEEPING MAGNETIC RESONANCE IMAGING (MRI) AS GOLD STANDARD

Abstract

Avascular necrosis of the femoral head is a common cause of musculoskeletal disability, and it presents a significant diagnostic and therapeutic challenge. Although patients are initially asymptomatic, avascular necrosis frequently leads to joint destruction, typically before the age of 50. Magnetic Resonance Imaging (MRI) is a non-invasive, rapid, and compassionate diagnostic tool commonly used by clinicians. This study aims to determine the diagnostic accuracy of X-rays in detecting avascular necrosis of the femoral head, using MRI as the gold standard. This Cross-Sectional Validation Study was conducted at the Department of Radiology, JPMC, Karachi, Pakistan. The study was conducted over six months after the synopsis approval, from November 6, 2021, to May 5, 2022. This study included all patients who met the inclusion criteria and visited the JPMC Hospital in Karachi. After explaining the procedure, risks, and benefits of the study, informed consent was obtained from all patients. All patients underwent X-rays, and those diagnosed with avascular necrosis of the femoral head underwent MRI. The collected data was entered into the attached proforma and used electronically for research. The mean age was 48.8±9.2, with 92 (63.0%) male and 54 (37.0%) female patients. The diagnostic accuracy of the X-ray was 82.88% in detecting avascular necrosis of the femoral head, with sensitivity and specificity of 82.05% and 83.82%, respectively. The positive predictive value (PPV) was 53.42%, and the negative predictive value (NPV) was 80.28%, using MRI findings as the gold standard. In conclusion, the use of X-ray in evaluating avascular necrosis of the femoral head was not helpful and comparable to MRI. Therefore, an MRI should be performed in every case of avascular necrosis of the femoral head to achieve an accurate diagnosis. More prospective and well-controlled trials are required to validate the current findings.