A prospective scintigraphic study of avascular necrosis of bone in renal transplant patients.

Avascular necrosis of bone (AVN) may cripple a patient who has had a successful renal transplant. The authors have attempted to gain more knowledge of this condition by undertaking a prospective survey to determine as accurately as possible the incidence of AVN in renal transplant patients. Routine six-month whole body bone scans were performed with 99mTechnetium Methylene Diphosphonate in 42 consecutive surviving renal transplant patients. The survey started in 1978-79, and patients were followed for a minimum of two years and a maximum of three years. As a result, seven were found to have AVN that would have remained undetected in two of the patients if routine whole body bone scanning had not been conducted. Despite a reduction in steroid dosage in recent years, the incidence of AVN in the authors' patients remains high at 17%. Bone scan appearances in renal transplant patients were classified and subdivided into four groups. By linking bone scans and radiographic and postmortem appearances of the femoral head, one very early case of AVN was detected. Routine bone scanning provided a more accurate estimation of the incidence of fractures in renal transplant patients (12%).