No abstract

The objective of the study was to evaluate the clinical, functional, and biomechanical symptoms in patients with anterior cruciate ligament (ACL) rupture before and after ACL reconstruction. The study enrolled 20 patients and 20 healthy subjects as controls. Walking biomechanics was assessed at three time points: before surgery and three months and a year or more after surgical reconstruction. Impact loads on both sides differed significantly from the respective values before surgery (p<0.05). Walking cycle duration decreased with time after surgery. On both sides (affected and unaffected), hip movement amplitudes were significantly smaller than in control (p<0.05). They remained so in the follow-up periods after the reconstruction. Before ACL reconstruction, the amplitude of the main flexion of the knee was significantly reduced both on the affected and unaffected sides. The amplitude gradually increased after the reconstruction, and a year post-surgery, it reached, on the operated side, the same values as in the control group. Complete functional recovery of the knee joint was not achieved within a year after the ACL surgical reconstruction. The remaining changes, however, were not clinically pronounced and could only be detected by instrumental gait analysis. The compensatory processes developed bilaterally, in both the hip and knee joints.

Materials and methods. The authors studied gait biomechanics in respect of time, velocity and dynamics in 34 patients with verified ACL rupture including 11 patients (first group) before the surgery and 23 patients (second group) after the surgery. Patients of the first group were followed in the period from 1 week up to 6 years (mean-18 months), of the second group-from 1.5 months up to 5.5 years (mean-13 months). Patients of the second group underwent standard arthroscopic ACL reconstruction with semitendinous and gracillis tendon autograft. Biomechanical gait examination was performed using strap down inertial motion sensors that register rotation angles in space. The authors measured time phases of gait cycle, movements in hip and knee joints in three mutually perpendicular planes as well as walking shock load. Results. Time phases of gait cycle in both groups demonstrated normal values both on healthy and affected limbs. Movements in hip and knee joints were within the normal range, no reliable differences in the analogous indices for each limb were reported. Shock load in walking was registered within 1.6 g, symmetrical on both sides; shock load dynamics was absent in the group of patients after the surgery. Study results did not identify functional disorders during random flat surface waking that would be specific for ACL lesion as compared to normal values and to intact limb. However, a certain tendency was observed towards an increase of flexion-extension movement range in the knees following ACL reconstruction. The reported differences were not credible. Conclusion. The authors did not observe any specific functional knee joint instability during normal activities in the first group of patients with ACL rupture. On the one hand, that means that ACL lesion does not manifest in such circumstances, on the other-knee joint instability does not progress during flat surface walking at a random pace. The obtained results give certain ground to reconsider the concept of "knee joint instability".