Unilateral stance strategies of athletes with ACL deficiency

Abstract

Aberrant movement strategies are characteristic of ACL-deficient athletes with recurrent knee instability (noncopers), and may instigate premature or accelerate joint degradation. Biomechanical evaluation of kinematic changes over time may elucidate noncopers' responses to neuromuscular intervention and ACL reconstruction (ACLR). Forty noncopers were randomized into a perturbation group or a strength training only group. We evaluated the effects of perturbation training, and then gender on knee angle and tibial position during a unilateral standing task before and after ACLR. No statistically significant interactions were found. Before surgery, the strength training only group demonstrated knee angle asymmetry, but 6 months after ACLR, both groups presented with similar knee flexion between limbs. Aberrant and asymmetrical tibial position was found only in females following injury and ACLR. Neither treatment group showed distinct unilateral standing strategies following intervention; however, males and female noncopers appear to respond uniquely to physical therapy and surgery.

Figure 1

Algorithm for noncoper randomization and testing procedures.

Figure 2

Tibial position (m) of each subject before pre-operative intervention, after preoperative intervention, and 6 months post anterior cruciate ligament reconstruction (ACLR).

Figure 3

Knee flexion angle (degrees) of the involved (solid lines) and uninvolved (dashed) limbs of the PERT and STR before preoperative intervention, after preoperative intervention, and 6 months post ACLR.

Figure 4

Tibial position of males (top graph) and females (bottom graph) before preoperative intervention, after preopera-tive intervention, and 6 months post ACLR.

Figure 5

Knee flexion angle (degrees) of males and females before preoperative intervention, after preoperative intervention, and 6 months post ACLR.