Functional knee brace effects during walking in patients with anterior cruciate ligament reconstruction

The purpose of this study was to compare lower extremity joint kinematics and kinetics during walking with and without a functional knee brace in patients with recent anterior cruciate ligament reconstructions. Seven volunteers walked at 1.26 m/s with and without one of two functional knee braces 3 weeks after surgery. Eleven uninjured subjects were also tested as a control group. Video and ground-reaction data were collected and combined with inverse dynamics to estimate the joint positions, moments, and powers during the stance phase. Patients with ligament reconstructions were more erect with the brace, using 19% less knee flexion compared with walking without the brace. Areas under the internal extensor moment curve (angular impulse) and power curve (work) at the hip increased 40% and 44%, respectively, while walking with the brace. Extensor angular impulse decreased 41% at the knee while using the brace, and plantar flexor angular impulse and work increased 21% and 30%, respectively, at the ankle. While walking with the brace, the patients still had different kinematics, moments, and powers than the control subjects. The reduced extensor moment at the knee in the braced condition indicated that the load on the recently reconstructed ligament was reduced and that the brace protected the ligament during the stance phase of walking. We concluded that functional knee braces may be one means of developing neuromuscular adaptations during gait after anterior cruciate ligament reconstruction surgery.