The Biomechanical Research Of Anterior Cruciate Ligament Reconstruction With Single-layer And Double-layer Bone-patellar Tendon-bone Allograft

Objective:Anterior cruciate ligament (ACL) injury is the most common problem inthe injury of knee joint. Because the self-healing ability of anterior cruciateligament is very poor, currently graft reconstruction is the main methods forthe treatment of anterior cruciate ligament injury. Bone-Patellar Tendon-Bone(B-PT-B) is the most commonly autograft in anterior cruciate ligamentreconstruction. The initial strength of the autograft is the precondition of theeventually function of the knee joint. The graft-tunnel mismatch in theproximal part of the tibial tunnel and the ultimate strength after thepostoperative ligamentization process have been potential problems for thetraditional10-mm wide graft. The double-layer bone-patellar tendon-boneallograft can match to the graft with the bone tunnel better and increase theinitial strength of the graft. The purpose of this study is to reconstruct theanterior cruciate ligament of the rabbit with single-layer and double-layerbone-patellar tendon-bone allograft, observe the biomechanics of the autograft,then explore the effect of the double-layer bone-patellar tendon-bone allograftfor anterior cruciate ligament reconstruction.Methods:1. Under the aseptic condition, allografts were randomly taken from oneside of rear limbs of sixteen mature New Zealand White rabbits. With themethod of Wang Fei et al, the grafts were respectively prepared intosingle-layer and double-layer. Then the geometric characteristics of them weredetermined. The fresh graft was keeped with sterile chamber in the refrigeratorof-152℃for fourteen days.2. Thirty-two New Zealand white rabbits were used in this study, and divided into2groups (A and B). An ACL reconstruction was performed ingroup A by using single-layer bone-patellar tendon-bone allograft, and ingroup B by double-layer bone-patellar tendon-bone allograft.3.The specimens were collected at3,6,12and24weeks after surgery. Thebiomechanics of the bone-allograft-bone were determined. Statistical analysiswas taken to compare the biomechanics of ACL reconstruction with twoallografts.Results:Rabbits had a good knee function and grew in good condition. The drawertest and Lachnman test were both negative in all the Rabbits. In terms of thesingle-layer allograft, double-layer allograft has a greater cross-sectional area，which has led to a better graft-tunnel match. The maximum load, maximumstress, maximum displacement of group B is significantly greater than group A(P<0.05).Conclusions:Both single-layer and double-layer allograft can effectively restablish thestructure and function of anterior cruciate ligament and maintain the stabilityof the knee joint. Double-layer allograft has a better graft-tunnel match, whichcan provide a more powerful strength. Double-layer bone-patellar tendon-boneallograft is the ideal choice for the anterior cruciate ligament reconstruction.