The routine culture of allograft tissue in anterior cruciate ligament reconstruction

Background: Allograft tissue is an acceptable alternative to autograft tissue in anterior cruciate ligament (ACL) reconstruction. However, several infections associated with tissue procurement have led some to consider routine intraoperative cultures of allograft tissue before implantation. A positive culture result presents a treatment dilemma in the asymptornatic patient. Hypothesis: Treatment of culture swab-positive allograft tissue is unnecessary if there is no evidence of clinical infection. Study Design: Cohort study (prognosis); Level of evidence, 2. Methods: Retrospective analysis was performed on 247 cultures taken in 321 consecutive ACL reconstructions from a single surgeon. Allograft cultures were taken intraoperatively before antibiotic washing and implantation. All patients received standard prophylactic antibiotics consisting of intravenous vancomycin and perioperative cefazolin, and were routinely monitored in the postoperative period for signs of infection. Results: Twenty-four of 247 (9.7%) cultures were positive after implantation. Sixteen of these (67%) grew organisms of high pathogenicity, whereas 8 (33%) were of low pathogenicity. Cultures were classified as poor, scant, or rare in all 24 patients. These patients did not receive additional antibiotics, and none went on to develop septic arthritis or wound complications. The 2 cases of septic arthritis had negative intraoperative cultures. Conclusions: Treatment of low-virulence organisms or minimal growth high-virulence organisms is unnecessary if no evidence of clinical infection exists. The results may call into question the utility of routinely culturing allograft tissue as positive results did not correlate with infectious complications.