The mechanical characteristics and early-stage clinical effects of double bundle anterior cruciate ligament reconstruction with femoral direct fiber insertion

Objective To investigate the finite element analysis and early-stage clinical effects of double bundle anterior cruciate ligament (ACL) reconstruction with femoral direct fiber insertion. Methods From June 2016 to June 2017, a total of 26 cases of ACL reconstruction were analyzed retrospectively, including 15 males and 11 females, mean age 30.5±4.6 years. All the patients underwent ACL reconstruction by the same operator. The early-stage clinical effects were evaluated by the finite element analysis, pivot shift test, Lachman test, preoperative and postoperative IKDC score, Lyshlom score, KT-2000, 3D-CT and MRI. Results The finite element analysis confirmed theoretically that the double bundle ACL reconstruction with femoral direct fiber insertion could restore the stability and biomechanics of knee effectively. The results of pivot shift test were negative, and the Lachman test were negative except one first-stage positive after operation. 3D-CT showed that the bone tunnel was located in the direct fiber area. MRI showed clearly the ACL of double bundle after operation. Lysholm score increased from 56.5±3.6 pre-operation to 61.9±3.2 at three months after operation, and up to 88.5±2.0 two years after operation with statistically significant difference (F=824.72, P<0.001). IKDC score increased from 48.3±2.8 before operation to 58.0±2.0 at three months after operation, and to 92.5±2.6 at two years after operation with statistically significant difference (F=2 256.66, P<0.001). KT-2000 side-side difference decreased from 5.6±0.7 mm to 1.6±0.5 mm at three months after operation, and to 1.5±0.6 mm at two years after operation with statistically significant difference (F=389.14, P<0.001). Conclusion The double bundle ACL reconstruction with femoral direct fiber insertion can effectively restore the stability and the biomechanical environment of knee joint with satisfied early-stage clinical effects. Key words: Anterior cruciate ligament; Reconstructive surgical procedures; Finite element analysis