In the spring of 2007, I was honored to receive the Mr. and Mrs. Charles S.S. Chow Research Scholarship. This honor allowed me to complete my thesis work for my Master of Science in the Department of Bioengineering at the University of Pittsburgh. My research topic was on various double bundle anterior cruciate ligament (ACL) reconstruction techniques. My thesis consisted of three comprehensive projects that looked into variables important to the outcome of double bundle ACL reconstruction. Double bundle ACL reconstruction has gained popularity in Europe and Japan over the last two decades. The procedure is designed to replicate the unique function of the two functional bundles of the native ACL. The first two projects determined how changing the knee flexion angle at which each graft was fixed, affected the force distribution of the two grafts in double bundle ACL reconstruction. With the knowledge gained from these two studies, we were able to determine an appropriate range of knee flexion angles for the fixation of the two grafts that would also reduce the risk of graft failure due to improper loading.
The third study of my thesis involved looking into an alternate technique that utilized only a single tibial and femoral tunnel, but maintained the advantages of having two grafts to replicate the two functional bundles of the intact ACL. In general, a double bundle ACL reconstruction requires that two tunnels be drilled in the femur, and either one or two tunnels in the tibia. However, in the event of a revision surgery, due to persistent instability or graft failure, problems could arise due to the two large tunnels already in existence. Therefore, we examined a new technique, in which one femoral tunnel was drilled for the first graft, while the second graft was fixed over the top on the lateral femoral condyle, to a more traditional double bundle procedure with two femoral tunnels for each graft. With the use of our laboratory’s robotic/universal force moment sensor (UFS) testing system, I was able to measure the knee kinematics of an intact knee, and compare this to the knee kinematics after cutting the ACL, as well as after the two double bundle ACL reconstruction procedures. In addition, to understand the function of the ACL and the ACL replacement grafts, the in situ force carried by the ACL to maintain knee stability was also measured and compared.
With the aid of the scholarship, I was able to complete my study. It is exciting to find that knee kinematics of our new single femoral tunnel could achieve similar knee kinematics to that of the knee with an intact ACL, as well as the double bundle ACL reconstruction with two femoral tunnels. Therefore, I believe that my findings warrants further studies that include more complex loading conditions that simulate normal daily activities.
Without the generosity of the Chow Research Scholarship, I would not have been able to complete this final project that was so critical to my master’s thesis. The completion of such a complex project took longer than I had anticipated, and the funding provided through the Chow Scholarship allowed me to remain focused, so that I could do my experiments carefully, analyze my data correctly, and ultimately complete my thesis satisfactorily. Finally, I thank the ASIAM Institute Board of Directors and the Chow family for this prestigious scholarship.