Low-Dose Irradiation of Allografts for Ligament and Tendon Reconstruction

Soft tissue allografts for ligament and tendon reconstruction have been used successfully for many years, and their usage has increased dramatically in the past decade. The rate of soft tissue allograft usage in primary anterior cruciate ligament (ACL) reconstruction vs. autograft usage went up from 17% of all surgeries in 2002 to 46% of all surgeries in 20081. Allografts are either processed aseptically, with a sterility assurance level (SAL) of 10-3 if properly validated, or terminally sterilized at a SAL of 10-6. Low-dose, low-temperature gamma irradiation as a terminal sterilization method to treat aseptically processed tissue was introduced to provide a safe and reliable allograft option for surgeons and their patients, due to the previous history of allograft recalls. From 1994 to 2007, almost all allograft recalls were for musculoskeletal tissues, and they were due to improper or incomplete donor evaluation, contamination, recipient infection, and positive serologic tests2. Even with increased regulation by the American Association of Tissue Banks (AATB), allograft recalls can still occur. Therefore, there is an increasing interest in sterilization methods that yield a SAL of 10-6. This white paper will demonstrate that irradiated allografts provide the necessary biomechanical strength and safety needed for ligament and tendon reconstruction.