Autograft contamination during preparation for anterior cruciate ligament reconstruction

Background: The autograft preparation process for anterior cruciate ligament reconstruction has a potential for graft contamination. The purpose of this study was to evaluate the possibility of contamination of the bone-patellar tendon-bone and hamstring tendon autograft during preparation for anterior cruciate ligament reconstruction. Methods: A primary isolated reconstruction of the anterior cruciate ligament with use of bone-patellar tendon-bone autograft (thirty patients) and hamstring tendon autograft (thirty patients) was performed in a prospective, consecutive series of patients. Three tissue samples were obtained for culture from each graft at different time-intervals during the graft preparation. In addition, the erythrocyte sedimentation rate and the C-reactive protein level were evaluated preoperatively and on the third, seventh, and twentieth postoperative days, and the clinical course of all patients was monitored. Results: The time needed for graft preparation was significantly longer for hamstring autografts (nineteen minutes) than for bone-patellar tendon-bone autografts (ten minutes) (p = 0.032). In the hamstring group, cultures of graft tissue from four patients (13%) were positive for bacteria. In the bone-patellar tendon-bone group, cultures of graft tissue from three patients (10%) were positive for bacteria; the difference between groups was not significant (p = 0.923). No patient had development of a postoperative infection. There were no differences between patients with a contaminated graft and those with an uncontaminated graft with regard to postoperative changes in the erythrocyte sedimentation rate or the C-reactive protein level at all time-intervals. Conclusions: A high rate (12%) of autograft contamination can be expected during autograft preparation for anterior cruciate ligament reconstruction. The contamination rate is almost equal for both bone-patellar tendon-bone and hamstring tendon autografts. We could not identify an association between contaminated grafts implanted in the knee and postoperative inflammatory markers such as the erythrocyte sedimentation rate and the C-reactive protein level. Level of Evidence: Therapeutic Level II. See Instructions to Authors for a complete description of levels of evidence.