PMN elastase in bone and joint infections

PMN (polymorphonuclear neutrophil) elastase is a proteolytic enzyme which is a biochemical marker for abnormal granulocyte stimulation. In inflammation and sepsis, excessive neutrophil stimulation results in significant amounts of PMN elastase being released into the plasma which indicates the severity of the disease and its prognosis. In 62 patients with osteomyelitis or suppurative arthritis, PMN elastase had a diagnostic sensitivity of 81%, which is comparable to the nonspecific erythrocyte sedimentation rate. Sensitivity of C-reactive protein (CRP) was 71%, fibrinogen 54% and leucocyte count 26%. PMN elastase was also useful in the follow up of patients with bone and joint infections; in the early post-operative period it became normal more quickly than the other findings unless the patients developed complications. Ten days after operation, PMN elastase was normal in 75% of the patients compared to the CRP which became normal in only 25%. Later both results were similar: on discharge from hospital, PMN elastase was normal in 77% and CRP in 71%.