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J Knee Surg 2009; 22(2): 111-113
DOI: 10.1055/s-0030-1247734
Original Article

© 2009 Thieme Medical Publishers

A Biomechanical Analysis of Bone-Patellar Tendon-Bone Grafts After Repeat Freeze-Thaw Cycles in a Cyclic Loading Model

Gregory H. Lee, Ashwin Kumar, Eric Berkson, Nikhil Verma, Bernard R. Bach Jr , Nadim Hallab
  • The Division of Sports Medicine, Department of Orthopedic Surgery, Rush University Medical Center, Rush Medical College, Chicago, Ill
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Publication History

Publication Date:
14 January 2010 (online)

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ABSTRACT

The purpose of this study was to examine the biomechanical effects of bone-patellar tendon-bone (BPTB) grafts subject to repeat freeze-thaw cycles in a cyclic loading model. We hypothesized that repeat freeze-thaw cycles have deleterious effects on the tensile properties of BPTB grafts.

Thirty BPTB composite grafts were harvested from porcine knee specimens. Tendons were randomized into 3 groups: fresh, 1 freeze-thaw cycle (—80°C), or 2 freeze-thaw cycles. The grafts were cyclically loaded to simulate the forces on the anterior cruciate ligament during walking and running, prior to single cycle load-to-failure testing.

All tendon failures were mid-substance and occurred during the single cycle load-to-failure testing. There was no statistically significant difference in ultimate stress or strain between the groups. Repeat freeze-thaw cycles do not have deleterious effects on the tensile properties of BPTB grafts in a cyclic loading model. Potential influence on biologic graft healing or integration remains unknown.