Quantitative assessment of postural balance in patients with chronic anterior cruciate ligament injury- A controlled study

Purpose: Evaluation of single and double limb support postural balance in patients with Anterior cruciate ligament (ACL)injury and comparison of the postural strategy adopted after ACL injury/deficiency(ACLD) with that of an age-matched healthy individual.

Methods: The study group that included 33 subjects confirming inclusion criteria had undergone postural balance assessment using the HUMAC Balance system. The parameters of the center of pressure excursion were recorded on a force plate and compared with age, BMI matched 66 healthy volunteers of control group. The center of pressure excursions was monitored using dependable variables such as sway path length(cm), the average velocity of sway(cm/sec), and the mean COP stability score(%). The mobility component was recorded as the percentage (%) of time spent on each target.

Result: A decrease in postural balance in the injury group was evidenced by a statistically significant decrease of stability score(p = 0.015), increase in path length(p = 0.002) and decrease on time on target mean score (p= <0.001),. Although, the stability score path length and average sway velocity scores in the sound limb of the ACLD group showed impaired balance, the differences were not statistically significant (p = 0.180, p = 0.561, and p = 0.639 respectively) when compared with the dominant limb of the control group.

Conclusion: HUMAC balance system is an effective and simplified measure for quantifying postural balance. Although overall postural stability in ACL injury is impaired, static postural balance is maintained by the compensatory of strategy of sound limb. However, the quantitative parameters of postural stability for the sound limb, despite of a lower mean value, did not show statistically significant differences from the dominant limb of the controlled group.