title: Radioprotection provides functional mechanics but delays healing of irradiated tendon allografts after ACL reconstruction in sheep.
abstract: Successful protection of tissue properties against ionizing radiation effects could allow its use for terminal sterilization of musculoskeletal allografts. In this study we functionally evaluate Achilles tendon allografts processed with a previously developed radioprotective treatment based on (1-ethyl-3-(3-dimethylaminopropyl)carbodiimide) crosslinking and free radical scavenging using ascorbate and riboflavin, for ovine anterior cruciate ligament reconstruction. Arthroscopic anterior cruciate ligament (ACL) reconstruction was performed using double looped allografts, while comparing radioprotected irradiated and fresh frozen allografts after 12 and 24 weeks post-implantation, and to control irradiated grafts after 12 weeks. Radioprotection was successful at preserving early subfailure mechanical properties comparable to fresh frozen allografts. Twelve week graft stiffness and anterior-tibial (A-T) translation for radioprotected and fresh frozen allografts were comparable at 30 % of native stiffness, and 4.6 and 5 times native A-T translation, respectively. Fresh frozen allograft possessed the greatest 24 week peak load at 840 N and stiffness at 177 N/mm. Histological evidence suggested a delay in tendon to bone healing for radioprotected allografts, which was reflected in mechanical properties. There was no evidence that radioprotective treatment inhibited intra-articular graft healing. This specific radioprotective method cannot be recommended for ACL reconstruction allografts, and data suggest that future efforts to improve allograft sterilization procedures should focus on modifying or eliminating the pre-crosslinking procedure.
authors.affiliation: Department of Orthopaedic Surgery, Robert Wood Johnson Medical School - Rutgers University, 51 French St MEB Rm 424, P.O. Box 19, New Brunswick, NJ, 08901, USA.
authors.forename: Aaron U
authors.initials: AU
authors.lastname: Seto
authors.forename: Brian M
authors.initials: BM
authors.lastname: Culp
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Gatt
authors.forename: Michael
authors.initials: M
authors.lastname: Dunn
mesh_terms: D064591:Allografts / Q000187:drug effects* / Q000528:radiation effects*; D000818:Animals; D059549:Anterior Cruciate Ligament Reconstruction; D001696:Biomechanical Phenomena / Q000187:drug effects / Q000528:radiation effects; D001842:Bone and Bones / Q000187:drug effects / Q000528:radiation effects; D005720:Gamma Rays; D011837:Radiation-Protective Agents / Q000494:pharmacology*; D012756:Sheep; D013710:Tendons / Q000187:drug effects* / Q000528:radiation effects; D014945:Wound Healing / Q000187:drug effects* / Q000528:radiation effects
chemical_list: D011837:Radiation-Protective Agents