GAIT BIOMECHANICS ARE NOT NORMAL AFTER ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION AND ACCELERATED REHABILITATION

Purpose: Accelerated rehabilitation for anterior cruciate ligament (AC L) injury and reconstruction surgery is designed to return injured peo ple to athletic activities in approximately 6 months. The small amount of empirical data on this population suggests, however, that the torq ue at the knee joint may nor return until 22 months after surgery duri ng walking and even longer during running. Although the rehabilitation has ended and individuals have returned to preinjury activities, gait mechanics appear to be abnormal at the end of accelerated programs. T he purpose of this study was to compare lower extremity joint kinemati cs, kinetics, and energetics between individuals having undergone ACL reconstruction and accelerated rehabilitation and healthy individuals. Methods: Eight ACL-injured and 22 healthy subjects were tested. Injur ed subjects were tested 3 wk and 6 months (the end of rehabilitation) after surgery. Ground reaction force and kinematic data were combined with inverse dynamics to predict sagittal plane joint torques and powe rs from which angular impulse and work were derived. Results: The diff erence in all kinematic variables between the two tests for the ACL gr oup averaged 38% (all P < 0.05). The kinematics were not different bet ween the ACL group after rehabilitation and healthy subjects. Angular impulses and work averaged 100% difference for all joints (all P < 0.0 5) between tests for the ACL group. After rehabilitation, the differen ces between injured and healthy groups in angular impulse and work at both the hip and knee remained large and averaged 52% (all P < 0.05). Conclusions: Results indicated that after reconstruction surgery and a ccelerated rehabilitation for ACL injury, humans walk with normal kine matic patterns but continue to use altered joint torque and power patt erns.