Effect of an anterior-sloped brace joint on anterior tibial translation and axial tibial rotation: A motion analysis study

BackgroundAnterior tibial translation and axial tibial rotation are major biomechanical factors involved in anterior cruciate ligament injuries. This study sought to evaluate a brace prototype designed with an anterior-sloped joint, in terms of its efficacy in attenuating anterior tibial translation and axial tibial rotation during landing, using a motion analysis approach.MethodsTen healthy male subjects performed single-leg landing tasks from a 0.6-m height with and without the brace prototype. Ground reaction force and kinematics data were obtained using a motion-capture system and force-plates. Anterior tibial translation and axial tibial rotation were determined based on tibial and femoral marker reference frames. Vertical and anterior–posterior ground reaction forces, hip, knee and ankle joint range-of-motions and angular velocities, anterior tibial translation and axial tibial rotation were compared between unbraced and braced conditions using Wilcoxon signed-rank test.FindingsWe found no significant difference in peak vertical and anterior–posterior ground reaction forces (p = 0.770 and p = 0.332 respectively) between unbraced and braced conditions. Knee joint range-of-motion and angular velocity were lower (p = 0.037 and p = 0.038 respectively) for braced condition than unbraced condition. Anterior tibial translation and axial tibial rotation were reduced (p = 0.027 and p = 0.006 respectively) in braced condition, compared to unbraced condition.InterpretationThe anterior-sloped brace joint helps to attenuate anterior tibial translation and axial tibial rotation present in the knee joint during landing. It is necessary to test the brace prototype in a sporting population with realistic sports landing situations in order to assess its effectiveness in lowering anterior cruciate ligament injury risk.