Positive leukocyte and negative bone scintigraphy in extensive arthroplasty infection.

An 85-year-old male resident of a nursing home presented after a fall with a painful left hip, confusion, and fever. He had multiple medical problems including severe vascular disease and poor vision as a result of macular degeneration. An Austin Moore left hip prosthesis had been inserted for a fractured femoral neck several years before. A septic workup showed a raised leukocyte count but no other focal abnormality. Plain radiography showed a periprosthetic fracture of the left hip. Blood cultures grew beta-hemolytic group A Streptococcus sensitive to penicillin. Bone scintigraphy was thought to be consistent with loosening of the prosthesis without evidence of a recent fracture. Tc-99m leukocyte scintigraphy was markedly abnormal, with extensive soft-tissue uptake suggestive of a large periprosthetic infective collection. This was confirmed at surgery with drainage of 200 mL pus from the left hip, and deep and superficial soft tissues of the thigh. The trochanteric fracture was well granulated and thought to be of long standing. The prosthesis was removed and the patient was treated with appropriate antibiotics with good effect.