by Scott Baltic

Last Updated: 2007-10-10 13:45:21 -0400 (Reuters Health)

NEW YORK (Reuters Health) – Routine intraoperative cultures of allograft tissue used in anterior cruciate ligament (ACL) reconstruction appear not to predict risk of postoperative infection, according to a report in the September issue of the American Journal of Sports Medicine.

A retrospective analysis of 247 cultures taken from 321 consecutive anterior cruciate ligament reconstructions found that although 24 (9.7%) of the cultures were positive, none of those patients developed any signs of wound complication.

The researchers also note that the 74 patients excluded from this study because complete cultures were not obtained were followed for at least 3 months postoperatively, with no evidence of infection.

Furthermore, although there were two cases of septic arthritis, both requiring multiple debridements and eventual revision ACL surgery, in neither case was the intraoperative culture positive.

Dr. David R. Guelich of Chicago Orthopaedics & Sports Medicine and his associates report that the ACL reconstructions, which took place from January 2004 through May 2006, were all performed by the same surgeon, and all grafts were supplied by a single accredited tissue bank.

Cultures were taken intraoperatively for anaerobic, aerobic, fungal and atypical organisms, before the allograft tissue was given an antibiotic wash and implanted.

All patients received standard prophylactic antibiotics (intravenous vancomycin and perioperative cefazolin), and all received follow-up examinations at 2 weeks, 4 weeks, 6 weeks, 3 months, and 6 months.

Of the 24 cultures that were found to be positive after implantation of the tissue, 16 (67%) grew organisms of high pathogenicity and 8 (33%) were of low pathogenicity.

None of these 24 patients received additional antibiotics; none showed evidence of infection such as erythema, recurrent effusions, or high fever; and none developed septic arthritis or wound complications. All were discharged home the day of surgery.

"These results may call into question the utility of routinely culturing allograft tissue, as positive results did not correlate with infectious complications," Dr. Guelich told Reuters.

"Nevertheless," Dr. Guelich continued, "it is important to continue investigating the safety of allograft tissue, as its popularity continues to increase in ACL reconstruction."

The researchers suggest that future studies should focus on culturing allograft tissue before and after the antibiotic wash is applied.

Am J Sports Med 2007;35:1495-1499.