Maximum load to failure of high dose versus low dose gamma irradiation of anterior cruciate ligament allografts: A meta-analysis.
BACKGROUND
The objective of this study was to systematically evaluate the existing literature to compare the biomechanical effects of low dose and high dose gamma irradiation on commonly used ACL allografts.


METHODS
A systematic search was performed in PubMed, Cumulative Index for Nursing and Allied Health Literature (CINAHL), Cochrane Reviews, SCOPUS, and SportDiscus. Nine studies were identified that met the following inclusion criteria: 1) controlled laboratory study, 2) investigation of standard allografts for anterior cruciate ligament reconstruction (ACLR), 3) gamma irradiation (dose reported) and a negative control group, and 4) mechanical loading (results reported).


RESULTS
Nine studies met all inclusion and exclusion criteria. There was a dose-dependent relationship between radiation and decreased mechanical tendon integrity. Low dose radiation (<2.5Mrad [Mrad]) showed graft weakening with an average of 4.3% decrease in load to failure (standardized mean difference [SMD], 0.23; 95% CI 0.216, 0.68; p=0.31), whereas high-dose radiation showed a significantly larger (32.4% average) decrease in load to failure (SMD, 1.79; 95% CI 1.194, 2.38; p<0.001).


CONCLUSIONS
Gamma irradiation has a negative effect on tendon allograft strength that is dose-dependent, with particularly large effects noted at irradiation doses of ≥2.5Mrad.
The Ohio State University College of Medicine, Columbus, OH, USA; Division of Sports Medicine, Department of Orthopaedics, The Ohio State University Wexner Medical Center, Columbus, OH, USA.
Alex C
AC
DiBartola
Division of Sports Medicine, Department of Orthopaedics, The Ohio State University Wexner Medical Center, Columbus, OH, USA.
Joshua S
JS
Everhart
Division of Sports Medicine, Department of Orthopaedics, The Ohio State University Wexner Medical Center, Columbus, OH, USA; Sports Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA.
Christopher C
CC
Kaeding
Division of Sports Medicine, Department of Orthopaedics, The Ohio State University Wexner Medical Center, Columbus, OH, USA; Sports Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA.
Robert A
RA
Magnussen
Division of Sports Medicine, Department of Orthopaedics, The Ohio State University Wexner Medical Center, Columbus, OH, USA; Sports Medicine, The Ohio State University Wexner Medical Center, Columbus, OH, USA. Electronic address: david.flanigan@osumc.edu.
David C
DC
Flanigan
D064591:Allografts; D016118:Anterior Cruciate Ligament / Q000601:surgery*; D000070598:Anterior Cruciate Ligament Injuries / Q000503:physiopathology / Q000601:surgery*; D001696:Biomechanical Phenomena; D004307:Dose-Response Relationship, Radiation; D005720:Gamma Rays / Q000009:adverse effects*; D006801:Humans; D013710:Tendons / Q000503:physiopathology / Q000528:radiation effects* / Q000637:transplantation*; D013718:Tensile Strength
Allograft; Anterior cruciate ligament; Gamma irradiation