Extremely early stage osteonecrosis of the femoral head in a patient with hip pain secondary systemic steroid pulse therapy for Vogt-Koyanagi-Harada syndrome: A case report.

INTRODUCTION: Osteonecrosis of the femoral head (ONFH) is a corticosteroid-associated disease that mostly cause femoral head collapse and gait disturbance. At the final stage of ONFH, the most reliable treatment is total hip arthroplasty even in young patients. Although magnetic resonance imaging (MRI) is useful for early diagnosis, initial stages are asymptomatic, with pain intensifying after femoral head collapse.

PRESENTATION OF CASE: A 34-year-old female patient with rapid bilateral loss of vision was diagnosed Vogt-Koyanagi-Harada syndrome. She immediately received corticosteroid pulse therapy. While undergoing therapy, she complained of groin pain. The initial MRI of the hip did not show abnormal findings. As the right proximal thigh pain progressed, an MRI of the lumbar spine was performed. No compression of the spinal cord was observed, and right ONFH was suspected on the basis of a characteristic band image. The patient was diagnosed with Stage 1 ONFH 7 weeks after the initial symptoms. She was successfully treated by joint-preserving regenerative therapy using growth factor. After surgery, the patient completely recovered from pain.

DISCUSSION: The occurrence of hip pain while receiving corticosteroid therapy was very rare. The present case was considered a result of reduction of the blood supply to the femoral head induced by hip pain that progressed to ONFH for unknown reasons.

CONCLUSION: It is difficult to identify cases of corticosteroid-associated ONFH even in patients with potential risk. In this case, we could identify the patient extremely early based on the ONFH image and could provide joint-preserving regenerative therapy.