Effect of Knee Support on ACL-Deficient Knee Kinematics While Walking

Abstract

Functional knee supports are frequently used to protect the anterior cruciate ligament (ACL)-deficient knee. Despite the frequent use of supports, very few studies have evaluated the effect of knee support on knee motion. It is not clear how knee support influences the knee kinematics while walking. In order to clarify the effect of a knee support on knee joint kinematics while walking, we conducted a kinematic gait analysis of six young people (age 17-28 years) with unstable ACLs using ambulatory knee braces with a knee motion analysis system. Three kinematic knee motion parameters (knee flexion, anterior-posterior tibial translation, and internal-external rotation of the tibia relative to the femur) were measured when the subjects walked at their natural speed with four types of knee support (Nippon Sigmax) that differed in form and function and without knee support. The results showed that 1) the knee supports limited the range of motion of all three kinematic parameters, especially internal-external rotation of the tibia, compared to without support, 2) with knee support, internal rotation of the tibia was prevented significantly, and 3) the restraint of range of motion in the three kinematic parameters depended on the knee support stiffness, such as the material used and support components.