Effects Of A Unloading Protective Brace On In-Nivo Kinematics Of Knee

Objective:The knee joint consists of three compartments,and injury can occur in any one of them.Mobility-assisted interventions are included in the treatment plan for multicompartmental knee injuries.As a type of mobility-assisted intervention,the knee unloading protective brace can be used to limit excessive joint motion and reduce joint stress to prolong disease progression and prevent sports injuries again.However,there is no high-precision in-vivo 6-degree-of-freedom(DOF)kinematic studies of knee unloading protective brace have been found.The high-speed Dual-plane Fluoroscopic Imaging System(DFIS),the current gold standard for in-vivo skeletal kinematic measurements,allows observation of real changes under rapid skeletal motion.We used the DFIS system to verify the changes in knee in-vivo6 DOF kinematics with and without a overall unloading brace(OUB),to observe the realistic motion unloading protection effect of the OUB,and to provide a theoretical basis for brace intervention in patients with multicompartmental knee injuries.Methods:Ten healthy adult male college students were included in this study,and magnetic resonance imaging(MRI)data were acquired and examined on the right knee joint of each subject,and a three-dimensional(3D)model of the knee joint was created.Two-dimensional(2D)fluoroscopic images of the 10 subjects with and without the OUB under walking conditions at a treadmill speed of 3.6 km/h were acquired using high-speed DFIS.The established 3D knee skeletal model was then aligned with the2 D fluoroscopic images to obtain 3D kinematic data of the knee joint.Results:After with the OUB,the proximal-distal translational range of motion(ROM)of the tibiofemoral joint increased by 1.54 mm(P=0.035)during the stance phase of the gait cycle,with no significant changes in other DOFs;In the opposite toe off phase,the proximal-distal translational increased by 0.51mm(P=0.006),internal translational decreased by 2.15 mm(P=0.018),with no significant changes in other DOFs;In the heel rise period,proximal-distal knee translational increased by 0.70 mm(P=0.012),and anterior translational decreased by 2.81 mm(P=0.012),with no significant changes in other DOFs;In the opposite initial contact phase,with the OUB increased the proximal-distal knee translational by 1.08 mm(P=0.033),decreased internal translational by 2.15 mm(P=0.019),decreased extension by 5.64°(P=0.025),with no significant changes in other DOFs;In the toe-off period,the proximal-distal translational increased by 1.59±1.72mm(P=0.017),with no significant changes in other DOFs;Conclusion:During the five critical points of the gait cycle in support phase,the OUB can effectively increase the proximal-distal translational,reduce joint stress.OUB can play a positive role in the decompression protection of patients with multicompartmental knee injuries.