Article

Hamstring co-contraction may affect recovery from anterior cruciate
ligament reconstruction.
The aim of the study was to evaluate the changes in
hamstring co-contraction during the early postoperative stages. DESIGN:
Twenty-five patients with anterior cruciate ligament reconstruction were followed
up for 1-3 mos postoperatively, during which the Lysholm and International Knee
Documentation Committee questionnaires were completed and surface electromyograms
were assessed during terminal knee extension maximum voluntary contraction and
step-up tests. The integrated electromyogram of the tested muscles and
co-contraction ratio were analyzed. RESULTS: Co-contraction ratio during terminal
knee extension maximum voluntary contraction at 3 mos postoperatively was
significantly less than that at 1 mo postoperatively (P < 0.0083), and it did not
significantly differ from that of the uninvolved knee. In contrast, the
co-contraction ratio during step-up was significantly higher at 2 and 3 mos
postoperatively than that before surgery (P < 0.0167) and for the uninvolved knee
(P < 0.05). Moreover, the postoperative hamstring co-contraction ratio in
patients with a chronic injury was significantly higher during the step-up test
than in patients with an early injury (P = 0.017). CONCLUSIONS: Hamstring
co-contraction ratio during terminal knee extension maximum voluntary contraction
recovers during the early postoperative stages. However, hamstring co-contraction
ratio during step-up, which may be related to knee joint proprioception, remains
high, particularly for patients with a chronic injury. CLINICAL TRIAL:
ChiCTR-COC-17011167.

Langue : ANGLAIS