Osteonecrosis (also called aseptic necrosis, ischemic necrosis, or avascular necrosis) is bone infarction caused by a lack of blood supply. It may be an idiopathic or a primary disorder, secondary to a systemic condition, or due to trauma. Conditions associated with osteonecrosis of the femoral head include femoral neck fracture, hip dislocation, occult or minor trauma, sickle cell disease, collagen vascular diseases, alcohol abuse, renal transplant, systemic lupus erythematosus, dysbarism, chronic pancreatitis, exogenous steroid administration, Cushing disease, decompression sickness, Gaucher disease, and renal osteodystrophy. Osteonecrosis of the hip may cause pain anywhere from the buttock to the knee. X-ray, CT, or MRI may aid in diagnosis. Joint replacement may be needed.
Osteomyelitis is an infection of the bone that results in bony destruction commonly caused by Staphylococcus aureus. Patients have local pain and may have associated warmth, swelling, and erythema. Imaging may be normal. MRI is the preferred imaging study but bone biopsy is required for confirmation. The acutely ill patient should receive high-dose, broad-spectrum, parenteral antibiotics based on the patient's risk factors and most likely organisms (Table 179-3).
Osteitis pubis occurs following pregnancy, in athletes due to overuse of the adductors and gracilis muscles, and after bladder and prostate surgery. It causes pain in the region of the pubis and generally resolves over a period of months with rest and NSAIDs. Myositis ossificans (also known as heterotopic calcification) is the deposition of bone in abnormal sites after direct trauma. Pain and a palpable mass will be present. Pain or physical obstruction may limit motion in the affected muscle or joint. Surgery may be required.