Summary
This research aims to assess how repetitive loading plays a role in the fatigue of the ACL structure after repetitive/cycling loading
Abstract
Mechanisms of Anterior Cruciate Ligament Injury During Different Cycling Loading. A Porcine Study
Jason Koh1, MD, Asheesh Bedi1, MD, Sunjung Kim2, PhD, Farid Amirouche1,2, PhD
2Department of Orthopaedic Surgery, University of Illinois at Chicago, Chicago, Illinois, USA
1Department of Orthopaedic Surgery, University Health System, Skokie, Illinois, USA
Abstract
The anterior cruciate ligament (ACL) is an essential stabilizer in the kinematics of the knee. Athletes in high-demand sports such as soccer, football, and basketball and trauma victims frequently injure their ACLs. An anterior cruciate ligament (ACL) tear is the most common knee injury. There are between 100,000 and 200,000 ACL ruptures annually in the United States alone [1-3].
The knee is a complex dynamic structure where the primary function of the ACL is to control anterior translation of the tibia and may play a secondary restraining function of limiting the tibial rotation.
The ACL is often said to comprise two bundles: an anteromedial bundle tight in flexion and a posterolateral bundle tight in extension. This ligament is believed to weaken with time, and fatigue significantly contributes to its premature failure. Most athletes subject the knee to high performance, flexion-extension, and torsion at high frequency. According to the National Collegiate Athletic Association (NCAA) injury surveillance system, which has tracked all injuries associated with United States college athletics since 1988, American football players sustain the most considerable number of ACL tears, but these are contact injuries. It’s also known that most ACL tears occur from noncontact athletic injuries. Female athletes sustain higher rates of ACL injury per athletic exposure across sports and countries.
Purpose
This research aims to assess how repetitive loading plays a role in the fatigue of the ACL structure after repetitive/cycling loading at a rate of 1Hz. The relationship between cycles 200, 500, 1000, and 2000 will be analyzed regarding load control versus the overall stretch, micro-fatigue damage, and the load-to-failure force-displacement relation. Previous ACL cycling work has focused on low cycling rates of 100 cycles or less; we believe active athlete knees are subjected to much higher cyclic rates.
Methods
Four groups of ten porcine knee specimens will be carefully dissected and mounted on an apparatus for knee simulation in our Biomechanics Laboratory. The knees will be kept hydrated throughout the testing procedure. The linkage system allows for load compression and cycling, ensuring proper alignment and fixation to prevent slippage. Set the testing apparatus in displacement control mode and ensure the load is within 2 to 3 times body weight. We will test diverse groups at different cycle rates of 200, 500, 1000, and 2000 cycles to assess the ligament's fatigue response at various stages. During the test, we will monitor the applied displacement, load, and other relevant parameters. Finally, each specimen will be subject to failure, and maximum load, displacement, and other relevant parameters during the tensile test will be recorded.
Conclusion
The results will provide insight into ACL load fatigue and structural micro-stress rates that lead to injuries. We will analyze the data from the fatigue and tensile failure tests to evaluate the ligament's behavior and mechanical properties. Correlate the fatigue performance with the ligament's tensile properties to understand the relationship between fatigue and failure.