Postural control after anterior cruciate ligament reconstruction

Abstract

Injury in the anterior cruciate ligament (ACL) of the knee joint seems to affect the performance during maintenance of upright stance. However, the influence of ACL lesion or reconstruction on postural control is still unclear. This study examined the single and double-leg upright stance in 10 subjects who had undergone unilateral ACL reconstruction and in 10 subjects with normal knees. Participants w e r e submitted to three experimental positions on a fixed force platform: double, right and left-leg stance, with eyes closed. A three-dimensional system infrared emissor was used to obtain information about body oscillation. The results revealed that the mean sway amplitude and frequency, mean displacement speed and area, in antero-posterior and medial-lateral directions, were lower in double-leg stance than in single-leg stance, for both groups (p<0.05). Furthermore, mean sway amplitude and mean displacement area, in both directions, were larger in reconstructed-leg stance than in all other positions (p<0.01). These results indicated that ACL substitution by a graft has effect on postural control in tasks that require maintaining the upright stance on the reconstructed-leg. This seems to occur because w i t h the ACL repalcement by a graft, the information from the somatosensorial system still remains impaired.