Comparison of quadriceps and hamstring muscle strength after exercises with and without blood flow restriction in the postoperative period of the anterior cruciate ligament: a randomized controlled trial.

BACKGROUND The anterior cruciate ligament (ACL) reconstruction surgery takes the patient through a period where muscle mass loss occurs. The blood flow restriction combined with strengthening exercises can be an alternative to improve the muscle strength of the quadriceps and hamstrings in the postoperative period of ACL reconstruction. Objective Compare the gain in muscle strength between exercises with and without occlusion in the quadriceps and hamstring muscles in the postoperative period of reconstruction of the anterior cruciate ligament. Methods This is a randomized, prospective, longitudinal clinical trial, parallel, analytical, experimental type, with random allocation.The study included the participation of postoperative patients, with reconstruction of the anterior cruciate ligament. The isometric muscle strength of knee extension and flexion was evaluated using a digital hand dynamometer and the physical function of the knee, using the Lysholm, KOOS and IKDC questionnaires in the pre -operative and after 4, 8 and 12 weeks. All patients signed a written informed consent form prior to the start of the study Results After comparing the rehabilitation of the groups, a statistical difference was observed in quadriceps muscle strength (p <0.01) after 12 weeks and hamstrings (p <0.01) after 8 and 12 weeks in the injured legs. In the analysis of the participants' physical function, there was a significant difference in the Lysholm questionnaire (p <0.01) after 8 and 12 weeks, in the KOOS pain questionnaire (p <0.01) after 4 weeks, symptoms and daily activities (p <0, 01) after 8 and 12 weeks, quality of life (p <0.01) after 12 weeks, and in the IKDC questionnaire (p <0.01) after 8 and 12 weeks. Conclusion The blood flow restriction has proved to be efficient for improving muscle strength of the quadriceps, hamstrings and physical function of the knee after reconstruction of the anterior cruciate ligament in early rehabilitation.