A biomechanical analysis of bone-patellar tendon-bone grafts after repeat freeze-thaw cycles in a cyclic loading model.
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 degrees 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.
Lee
Gregory H
GH
Division of Sports Medicine, Department of Orthopedic Surgery, Rush University Medical Center, Rush Medical College, Chicago, IL 60612, USA.
Kumar
Ashwin
A
Berkson
Eric
E
Verma
Nikhil
N
Bach
Bernard R
BR
Hallab
Nadim
N
D000465:Algorithms; D000818:Animals; D016118:Anterior Cruciate Ligament / Q000637:transplantation; D019645:Arthroplasty, Replacement, Knee / Q000379:methods; D001696:Biomechanical Phenomena; D050376:Bone-Patellar Tendon-Bone Grafting / Q000379:methods*; D004548:Elasticity; D005615:Freezing; D007719:Knee Joint / Q000601:surgery; D023421:Models, Animal; D017847:Patellar Ligament / Q000601:surgery / Q000637:transplantation; D011897:Random Allocation; D034421:Sus scrofa; D013552:Swine; D013718:Tensile Strength