Avascular Necrosis of the Hip: A Post COVID-19 Sequela

A 60-year-old African American male presented to the hospital with seven months of progressively worsening left anterior hip pain with no known trauma. Two months after the pain onset, he underwent an x-ray of the pelvis with the lateral left hip, revealing dystrophic soft tissue calcification adjacent to the superolateral left acetabulum. Pain at this time was attributed to presumed sciatica vs arthritis. The patient underwent multimodal treatment for his pain without relief. In the month prior to the presentation, the patient also developed right hip pain. He then underwent a bilateral hip x-ray, revealing left femoral neck lucency suspicious for a nondisplaced fracture. CT pelvis was ordered at this time for further evaluation and demonstrated bilateral subcapital hip fractures. He was subsequently discharged from the emergency department with pending laboratory work and plans for close outpatient orthopedic surgery follow-up. The following day, the patient was instructed to return to the hospital due to an elevated erythrocyte sedimentation rate of 39 mm/hr and C-reactive protein of 41.6 mg/L. Subsequent MRI pelvis revealed bilateral subcapital femoral neck fractures with avascular necrosis (AVN) requiring surgical intervention with bilateral hip arthroplasty. Our patient underwent an extensive workup with no evidence of traditional risk factors for osteonecrosis, osteopenia, or other bone diseases. A pertinent finding in the patient's history was an admission for severe SARS-CoV-2 (COVID-19) infection 10 months prior. 'Long COVID' is a complex illness that has been shown to affect intravascular blood flow, and likely contributed to the development of bilateral hip AVN in our patient. Given this novel presentation, it is crucial that AVN be considered early in evaluating anterior hip pain for patients with a history of COVID-19 infection in order to avoid severe consequences such as femoral neck fractures.