To analyze the rate of allograft contamination from living donors using a swab culture method and to determine the necessity of antibacterial processing.

From September 2001 to June 2004, 334 allografts were obtained from living donors undergoing total joint arthroplasty. Two hundred and fourteen allografts were obtained from the femoral heads, 86 from the knee joint, and 34 from other sources. All allografts from donors with inflammatory diseases were discarded. After retrieving the graft, the entire surface of the allograft was carefully swabbed, and the specimen was inoculated and cultured on blood agar for 48 hours. A bacterial culture with the entire tissue was also carried out on discarded allografts, and the rate of contamination was compared with that of used allografts.

Of the 334 allografts, 20 (6%) allografts were culture positive using swab method. 132 allografts were discarded. The reasons for discarding were a prior medical history in 26, no informed consent in 54 and a positive blood test in 10. The rate of contamination of the discarded allografts was 15% (20/132) using the swab method, and 19% (25/132) using entire tissue culture method. The sensitivity of the swab culture technique was only 44%.

The low sensitivity implies that the swab method is unsuitable for detecting bacterial contamination. Unprocessed swab-culture-negative grafts may be contaminated with organisms that can cause infections. Therefore, additional antibiotic processing such as gamma-irradiation will be required.