Introduction: Avascular necrosis (AVN) of femoral head can be defined as cellular death of bone due to loss of blood supply because of any reason. It affects the individuals at a relatively younger age and males are affected more commonly as compared to females. Though the exact pathophysiology is not known, but loss of blood supply causing death of osteocytes is the final component of AVN. Magnetic resonance imaging is reported to be highly sensitive and specific for the diagnosis of AVN and helps in early diagnosis. We conducted this study to analyze role of MRI in evaluation of avascular necrosis of femoral head. 

Materials and Methods: This was a prospective study conducted in the department of radiology of a tertiary care medical institute situated in an urban area. 50 patients having avascular necrosis of femoral head were included in this study on the basis of inclusion and exclusion criteria. Institutional ethical committee approved the study and informed consent was obtained from the patients. Demographic details and detailed history was noted in all the cases. MRI of both hips was done in all patients. MRI findings were studied. Statistical analysis was done using SSPE 16.0 software. For statistical purposes p value less than 0.05 was taken as statistically significant.

Results: In this study of 50 patients with avascular necrosis of femoral head there 43 (86%) males and 7 (14%) females with M: F ratio of 1:0.16 most of the patients (56%) were between 20-40 years and the mean age of patients was found to be 38.48 ± 13.28 years. AVN of femoral head was present bilaterally in 31 patients (62 %) and unilateral in 19 patients (38%). The most common risk factor associated with avascular necrosis of femoral head was alcohol consumption (56%). Most common stage of AVN was found to be Stage II (39.50%). The most common MRI sign in studied cases was double line sign which was present in 73/81 (90.12%) femoral heads. Stage II and III AVN was more common in age group of 21-30 years whereas stage IV AVN was more common in age group of 41-50 years. Effusion was present in 57 hip joints. Bone marrow edema was seen in 68 femoral heads out of 81 affected in our study. On the basis of MRI most common compartment to be affected was found to be antero-superior compartment (51.85%). Finally the analysis of the cases on the basis of Steinberg Staging showed that the out of 81 femoral heads Stage IIIC was the most common stage seen in 25 femoral heads (30.86 %).

Conclusion: Magnetic resonance imaging is highly sensitive and specific imaging technique for the early diagnosis of avascular necrosis of femoral head. Early diagnosis and appropriate intervention in cases with AVN of femoral head is associated with better outcome. This study demonstrates the diagnostic benefits of MRI in early detection of lesion and its properstaging.

Keywords: Avascular necrosis, Femoral Head, Magnetic resonance Imaging, Staging.

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Dr Mohammed Zeeshan Saleem

Junior Resident, Department of Radiology, MGM Medical College and Hospital