Abstract
Purpose
Evaluate allograft tissue commonly used in soft tissue reconstruction to determine whether stiffness and strength were significantly altered after grafts were treated with different sterilization methods. Unprocessed, irradiated, and grafts treated with supercritical CO2 were compared.
Methods
Thirty-eight anterior or posterior tibialis tendons were obtained from a tissue bank (Allograft Innovations, Gainesville, FL). Group I was unprocessed, group II was sterilized with gamma irradiation (20–28 kGy), and group III was sterilized with supercritical CO2. The grafts were pretensioned to 89 N for 300 s. Specimens were then loaded from 50 to 300 N at 0.5 Hz for 250 cycles before being loaded to failure at 50 mm/min. Dependent variables were compared between sterilization groups with one-way ANOVA (P < 0.05) and equivalence trial.
Results
There was no significant difference in load to failure or failure stress among groups I, II, and III. Group III resulted in 27–36 % lower stiffness than group I and II. This difference was significant at 1, 10, 50, 100, and 250 cycles. There was no significant difference in stiffness between group I and group II.
Conclusion
The two sterilization methods tested in this study do not affect allograft strength. The supercritical CO2 sterilization method resulted in significantly lower stiffness than unprocessed and irradiated allografts. However, the stiffness and strength of all groups tested were greater than that of published values of the native intact anterior cruciate ligament (ACL). This study provides previously unpublished mechanical test data on a new sterilization technique that will assist surgeons to decide which allograft to use in ACL reconstruction surgery.
Level of evidence
III.
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Acknowledgments
This study was funded by Stryker Orthopaedics (Mahwah, NJ, USA).
Conflict of interest
Monica Hawkins is an employee of Stryker Orthopaedics and owns stock in the company. This study was funded by Stryker Orthopaedics.
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Baldini, T., Caperton, K., Hawkins, M. et al. Effect of a novel sterilization method on biomechanical properties of soft tissue allografts. Knee Surg Sports Traumatol Arthrosc 24, 3971–3975 (2016). https://doi.org/10.1007/s00167-014-3221-0
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DOI: https://doi.org/10.1007/s00167-014-3221-0