Avascular Necrosis of the Femoral Head in a Healthy, Young, Adult Male

Background: Avascular necrosis (AVN) of the femoral head can be caused by a variety of factors including tobacco use, traumatic injury, or hypercoagulability. Hypercoagulability in the body can lead to the formation of thrombi in the microcirculation, resulting in many possible complications. This report will discuss a case of a healthy, young male who developed avascular necrosis of the femoral head as a result of Factor V Leiden. Case Information: A 30-year-old previously healthy male presented to the outpatient family medicine clinic with a chief complaint of severe pain in his right hip. The pain had been present for eight months and was progressively getting worse. The patient’s only past medical history was hyperlipidemia. He was not taking any medications, he exercised regularly, he worked as a sales representative, and he did not have any family history of clotting disorders. He had no history of trauma, tobacco use, alcohol consumption, or steroid use. On physical exam, he had extreme pain upon flexion of the right hip. An X-ray of the right hip showed equivocal broadening of the superolateral femoral head-neck junction suggesting mechanical impingement. He then presented two weeks later with more intense pain in his hip and was unable to walk. He was referred to orthopedic surgery, where an MRI was performed and showed Stage 3 avascular necrosis of the femoral head. He then saw hematology and testing revealed that he was heterozygous for a mutation in the r506q gene responsible for factor V, confirming his diagnosis to be Factor V Leiden. The patient had a right total hip arthroplasty and is doing well. Conclusions: AVN of the femoral head is a debilitating condition. When left untreated, it is estimated that between 70-80% of patients will progress to bilateral AVN, making diagnosing the underlying cause vital. Hypercoagulability is believed to be a major and common cause of AVN; thus, systemic anticoagulation therapy should be considered to prevent further complications, especially when a patient is homozygous for the mutation on Factor V. While other treatment options for AVN of the femoral head are available, when the necrotic lesion has become too large or the femoral head has collapsed, total hip arthroplasty remains the best option. Although many patients discover that they have Factor V Leiden due to family history, this patient was unusual in that he presented with an irreversible complication of the disease.