Studying the Balance of the Coper and Non-Coper ACL-Deficient Knee Subjects

PURPOSE It seems that there is an association between the anterior cruciate ligament (ACL) and stability of the knee. This study aimed to evaluate the balance condition of the injured and non-injured sides of the coper and non-coper ACL-D (deficient) subjects during single and bilateral standing conditions. METHODS This case-control study was carried out on 10 coper and 5 non-coper ACL-D knee subjects and 15 sex-age matched healthy subjects. A Zebris platform pedobarograph tool was used in this study. The subjects were tested barefoot during single and bilateral leg stance conditions. The outcome measurements included measurement of the center of pressure (COP) path line length, confidence ellipse area and sway velocity. RESULTS In double leg stance, data analysis revealed that the COP path line length, confidence ellipse area and sway velocity all showed a significant increase in the injured leg of the non-coper ACL-D subjects when compared to the injured leg of the coper ACL-D and healthy subjects (P=0.002). During single leg stance, all of the parameters showed significant increase in the injured leg of both coper and non-copers of the ACL-D subjects relative to the healthy subjects (P<0.05). CONCLUSION This study confirmed a balance deficiency in the injured and apparently healthy leg of the non-coper and coper ACL-D knee subjects. Increased COP path line length, sway velocity and the coinfidence ellipse area clearly showed an impaired body balance. The reduced postural control of the non-coper ACL-D knee subjects in bilateral standing could be more evidence of their poor knee stability status.