Hamstring autografts are associated with a high rate of contamination in anterior cruciate ligament reconstruction.

Purpose: To quantitatively evaluate the rate, type, and level of contamination of anterior cruciate ligament (ACL) hamstring autografts after harvesting and preparation or dropping onto the operating room (OR) floor.

Methods: Two hamstring autograft specimens were prospectively retrieved from each graft in a consecutive series of 50 patients undergoing primary isolated ACL reconstruction (100 specimens total). One specimen was retrieved immediately after harvesting and dropped onto the OR floor (dropped group). The other was retrieved just after graft implantation and before fixation (control group). Each specimen was incubated for aerobic and anaerobic growth, and the number of colony-forming units (CFU)/g was measured. Patients' clinical course was monitored for signs of surgical site infection (SSI).

Results: The control and dropped groups had positive culture rates of 11/50 (22%) and 16/50 (32%), respectively, with no significant difference between groups (n.s.). The most common organism in the control group was Staphylococcus epidermidis (45.5%) followed by S. aureus (36.4%). In the dropped group, the most common organism was S. epidermidis (31.3%) followed by Bacillus species (25%). The median (range) CFU/g among positive specimens in the dropped and control groups was 65 (8-150) and 10 (2-60), respectively (P = 0.0003). No patient developed postoperative SSI.

Conclusion: Intraoperative hamstring autograft contamination rates were high. Hence, routine prophylactic decontamination of all hamstring autografts after harvesting and preparation and before implantation is recommended.

Level Of Evidence: Controlled laboratory study.