MRI spectrum of avascular necrosis of femoral head in patients treated for COVID-19

Objectives: The objectives of the study were to analyze the spectrum of avascular necrosis (AVN) of the femoral head as seen in MRI images of patients treated for COVID-19. Material and Methods: The different patterns of the findings of AVN of the femoral head as seen in MRI images in 200 patients who received standard treatment for COVID-19 in the recent past and presented with hip pain were analyzed retrospectively. Results: No positive findings to suggest any femoral head AVN as per the Ficat and Arlet classification were seen in 94% of cases. Stage IV AVN was seen in 0 cases (0%). Stage I AVN was seen in 6 cases (3%). Stage II AVN was seen in 4 cases (2%). Stage III AVN was seen in 2 cases (1%). Conclusion: In patients who have received standard treatment for COVID-19 and who later developed hip pain, the incidence of AVN was seen in 6% of cases. It was mainly seen more in the younger population (<40 years of age) probably due to quick ambulation and return to daily work. Elderly patients were rarely affected. Normal MRI findings were more common in these cases. Among the positive MRI scans of such cases, mild findings of AVN (Stage I) were the most predominant.