[PMN-elastase as a marker in diagnosis and follow-up of bone and joint infections].

PMN elastase, a proteolytic enzyme, is a biochemical marker for pathologic granulocyte stimulation. In the presence of sepsis, excessive neutrophil stimulation occurs and significant amounts of PMN elastase are released into the plasma and serve as an indicator for the severity of the disease and the prognosis. PMN elastase is also a useful parameter for preoperative diagnostic management and postoperative follow-up of bone and joint infections. In patients with osteomyelitis and joint empyema (n = 48) PMN elastase had a sensitivity of 77%, which was only exceeded by that of the unspecific erythrocyte sedimentation rate (sensitivity 89%). Sensitivities of other inflammation parameters were lower: C-reactive protein (CRP) 67%, fibrinogen 50%, neopterin 32% and leukocyte count 21%. Determination of PMN elastase levels was also helpful in postoperative follow-up of patients with bone and joint infections. In the early postoperative period PMN elastase levels normalized more quickly than the other parameters unless patients actually developed complications. At the first postoperative determination (day 2-4 after surgery) 38% of the patients (n = 24) already had PMN elastase levels within the normal range (less than or equal to 40 micrograms/l) (CRP 13%). After 10 days PMN elastase was normal in 57% and CRP in 30% of the patients. Later on both parameters reacted similarly: by the time of discharge from hospital levels of PMN elastase were normal in 70% and CRP levels in 74%.