The role of the hamstrings in stabilizing a knee with ACL deficit / 中华物理医学与康复杂志

ABSTRACT

Objective:To investigate the effect of enhancing the strength of the hamstring on the stability of the knee joint.Methods:Thirty patients with anterior cruciate ligament (ACL) tears were randomly divided into a training group ( n=15) and a control group ( n=15). After the injury′s edema stage, all of the subjects received the standard 6-stage rehabilitation training for ACL injury, including isokinetic exercise, isometric tension and contraction exercise, single or bipedal jumping, proprioception exercises and cardiovascular exercise. On the basis of that standard training, additional hamstring strengthening training was given to the training group. It involved three sessions of weight-bearing flexion of the knee joint six to eight times, at least five times a week for three months. All of the subjects underwent the passive relaxation test (PRT), knee function scoring (Lysholm scores) and weight-bearing MRI before and within 1 month after the training. Anterior shift of the tibia (TAS) was measured using weight-bearing magnetic resonance imaging (MRI). Results:Before the training there were no significant differences between the groups in terms of average PRT or Lysholm scores. After the training, the average PRT score in neither group had improved significantly. The average Lysholm scores of the training and control groups were not significantly different either, though both groups′ averages had improved significantly compared with before the training. The average tibial shifts were also significantly smaller than before the training, with the training group′s average significantly smaller than that of the control group.Conclusion:Increasing hamstring muscle strength can reduce tibial anteversion in the weight-bearing upright position and improve the stability of the knee joint after ACL injury.