What is the pain source? A case report of a patient with low back pain and bilateral hip osteonecrosis.

BACKGROUND Low back pain is a common symptom arising from many possible sources and includes the possibility of the contribution of remote pathology. This report describes a patient with bilateral osteonecrosis of the femoral heads presenting with a primary symptom of low back pain. CASE PRESENTATION A 37-year-old male presented for evaluation of dominant pain that existed for approximately 6-12 months and was located in the right low back. Milder pain was also reported in the right hip. Low back and hip pain were both aggravated by weight-bearing activities. An evidence-based diagnostic evaluation revealed little indication for a primary pain source originating from low back structures. Radiographs revealed bilateral osteonecrosis with evidence of left femoral head collapse. CONCLUSION Hip osteonecrosis may have contributed to an atypical presentation of low back pain due to aberrant localization of pain and/or combined with altered biomechanical loading of musculoskeletal structures.