A 32 year old man presents with worsening pain in his right hip for 6 months. The pain was localized to the front of the hip, occurred with movement, and was associated with restriction of motion. There was no pain at rest. He also experienced pain in his right knee during the same time period. However, there was no associated swelling or restriction of knee motion. There is no history of previous trauma, and his medical and surgical histories are unremarkable. He has been consuming 3 to 4 glasses of whiskey on a daily basis for several years now. A complete blood count is found to be normal. His ESR is 5 mm/1h, while a C-reactive protein assay is within normal levels.
The X-ray of the right knee appears completely normal.
The x-rays reveal sclerotic and lytic areas in the head of the right femur, in association with a partial subchondral collapse. The joint space of the right hip joint is diminished. The left hip joint and femur appear normal.
The MRI demonstrates osteonecrosis (avascular necrosis) of the head of the right femur, with subchondral collapse and femoral head flattening. The right acetabulum appears normal, but there is narrowing of the joint space. The left femur and hip joint appear normal.
You realize that arthroscopy is probably not the most appropriate investigation right now.