Gait patterns before and after anterior cruciate ligament reconstruction.

The aim of this study is to determine how selected gait parameters may change as a result of anterior cruciate ligament (ACL) deficiency and following ACL reconstruction. The study was performed on 25 ACL-deficient subjects prior to and 6 weeks, 4 months, 8 months and 12 months after ACL reconstructive surgery by the bone-patellar tendon-bone technique. Gait analysis was performed using the zebris three-dimensional ultrasound-based system with surface electromyograph (zebris Medizintechnik GmbH, Germany). Kinematic data were recorded for the lower limb. The muscles examined include vastus lateralis and medialis, biceps femoris and adductor longus. The results obtained from the injured subjects were compared with those of 51 individuals without ACL damage. The acute ACL-deficient patients exhibited a quadriceps avoidance pattern prior to and 6 weeks after surgery. The quadriceps avoidance phenomenon does not develop in chronic ACL-deficient patients. In the individuals operated on, the spatial-temporal parameters and the knee angle had already regained a normal pattern for the ACL-deficient limb during gait 4 months after surgery. However, the relative ACL movement parameter-which describes the tibial translation into the direction of ACL-and the EMG traces show no significant statistical difference compared with the values of healthy control group just 8 months after surgery. The results suggest that: (1) development of a quadriceps avoidance pattern is less common than previously reported, (2) anterior cruciate ligament deficiency and reconstruction significantly alter the lower extremity gait pattern, (3) the gait parameters shift towards the normal value pattern, and (4) the re-establishment of pre-injury gait patterns--including the normal biphase of muscles--takes at least 8 months to occur.