Chapter 20 - Osteonecrosis and Organ Transplantation

Abstract

Osteonecrosis is a well-recognized complication associated with organ transplantation. It is a pathological condition characterized by the death of the cellular constituents of bone and marrow. The process of aseptic bone necrosis is associated with glucocorticoid use, and the mechanism by which glucocorticoids initiate the pathologic process has recently been elucidated. Rates are particularly high in patients with systemic lupus erythematosus. The incidence of osteonecrosis also increases in patients on dialysis. The exact prevalence of osteonecrosis after organ transplantation is, however, difficult to assess as many cases are clinically silent. The most common symptom of osteonecrosis is pain that is usually deep in nature, localized to the groin with occasional radiation down the thigh to the knee. Symptoms are usually exacerbated by physical activity and weight bearing and relieved by rest. In the late stages of osteonecrosis, pain is often present at rest, and patients may develop a limp, as they are no longer able to bear weight on the affected joint. Osteonecrosis affecting the bone beneath a weight-bearing joint surface is associated with a significant risk of developing a subarticular fracture, which appears to initiate the symptoms. Optimizing the dose of glucocorticoids has led to a significant reduction in the incidence of osteonecrosis post-transplantation. Substituting these agents entirely with calcineurin inhibitors may decrease this complication of the transplantation process even further. Early diagnosis using magnetic resonance imaging is essential for the success of available surgical interventions.