An investigation of postural control in postoperative anterior cruciate ligament reconstruction patients

To investigate quadriceps strength and static and dynamic balance in the anterior cruciate ligament (ACL)-reconstructed patient and to compare these findings with an age-matched, injury-free control group.

A 2 x 2 mixed-design analysis of variance (group x leg) was applied to the static posture, dynamic balance, and strength data. In addition, Pearson product-moment correlations were calculated to determine the strength of the relationships among the dependent measures. All data were collected in the Motor Control Laboratory at Indiana University.

The experimental group was composed of 20 individuals who had undergone ACL reconstruction with a patellar tendon autograft. The control group comprised 20 participants with no history of significant orthopaedic injuries to the lower extremities.

The dependent variables were sway path linear mean for the static condition, dynamic-phase recovery time after perturbation for the dynamic measure, and quadriceps peak torque for strength.

We found significant differences between the ACL and control groups on the measures of dynamic-phase duration and peak torque. The static sway variable did not show a significant difference.

Evaluation of the postural control system under 2 conditions, static and dynamic, showed differences between the ACL and control groups for the dynamic condition only. These results suggest the presence of independent control mechanisms for the control of static and more dynamic postures. In addition, because there were no differences between the injured and noninjured legs of the ACL group, the theory of a central postural control scheme is supported.