Change in posture control after recent knee anterior cruciate ligament reconstruction?

The aim of this study was to compare statical postures of a knee anterior cruciate ligament reconstruction (ACLR) population with a healthy control population. Thirty-five patients (age 25.5 +/- 5.8 years) were compared at 15 days after an anterior cruciate ligament reconstruction with 35 healthy, age and sex-matched subjects. Bilateral and unilateral postures were studied according to various stances, knee extension and 20 degrees knee flexion with opened and closed eyes, using a stabilometric platform. A comparison with the non-ACLR limb and the healthy limbs of the control population was carried out. The ACLR subjects present with the following: (i) a significant change in two-legged stance, i.e. distances covered by the centre of pressure projection are significantly increased; (ii) a postural alteration during the ACLR one-legged stance with knee extension and opened eyes in comparison with the non-ACLR limb; (iii) an incapacity for certain ACLR subjects to perform one-legged stance on the non-ACLR limb when there is no visual compensation. Only 11.4% (95% CI: 0.9-21.9%) and 42.8% (95% CI: 26.3-59.3%) of ACLR subjects are capable of maintaining correctly a one-legged stance posture with closed eyes on both sides (knee extension and flexion, respectively). The identification of the ACLR knee limb is possible from the one-legged stance postural test in knee extension and opened eyes condition. Because of a change in two-legged balance and of the incapacity for certain ACLR subjects to maintain one-legged stance with closed eyes, a central origin explaining the abnormalities of postural control is suggested.