Comparison of Quadriceps and Hamstring Muscle Strength after Exercises with and without Blood Flow Restriction following Anterior Cruciate Ligament Surgery: A Randomized Controlled Trial

Background: Muscle mass loss occurs following anterior cruciate ligament reconstruction surgery.Objective: To compare the gain in muscle strength in the quadriceps and hamstring muscles in patients following anterior cruciate ligament reconstruction surgery, using exercises with and without blood flow restriction.Methods: This is a randomized controlled trial, in which 50% (n = 14) of the participants were allocated to the intervention group and the remaining 50% (n = 14) to the control group. The study included the participation of postoperative patients, with reconstruction of the anterior cruciate ligament.Results: After comparing the rehabilitation of the groups, a statistical difference was observed in the quadriceps with an increase in muscle strength (p < 0.01) after 12 weeks and an increase in muscle strength hamstrings (p < 0.01) after 8 and 12 weeks in the injured legs of the intervention group compared to the control. In the analysis of the participants' physical function, there was an significant increase difference in the Lysholm questionnaire (p < 0.01) after 8 and 12 weeks, in the KOOS pain questionnaire (p < 0.01) after 4 weeks a decrease was observed, 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 there was an significant increase difference of the intervention group compared to the control.Conclusion: After anterior cruciate ligament surgery, exercises with blood flow restriction proved more efficient for improving the muscle strength of the quadriceps and hamstrings, and the physical function of the knee than the same exercises without blood flow restriction. LAY ABSTRACTAfter anterior cruciate ligament reconstruction surgery patients need to undergo a gradual process of rehabilitation. This prospective study compared muscle strength gain between exercises with and without blood flow restriction (BFR) in the quadriceps and hamstring muscles. Regarding knee extension, there was an improvement in muscle strength after 12 weeks in the injured legs. For knee flexion an improvement was observed at 8 weeks, in addition to improvement in functionality. The use of blood flow restriction in rehabilitation exercises after anterior cruciate ligament reconstruction was shown to be more efficient for muscle strength gain in the quadriceps and hamstrings and improvement in knee physical function.