Using Surface Electromyography To Assess VL?RF And VM Muscle Strength Pre-and Post-ACL Reconstruction

ObjectiveWe analyze the electrical signals of vastus lateralis?rectus femoris and vastus medialis muscle when patients stretch the knee after ACL(anterior cruciate ligament)rupture and ACLR(anterior cruciate ligament reconstuction)by using surface electromyography.Through assessing the abnormality of knee extensor function in patients with ACL rupture,we try to provide theoretical basis for guiding pre-and post-operative rehabilitation training.Methods20 patients with unilateral ACL rupture were enrolled as research objects from the department of sports medicine in Shanghai Sixth People's Hospital between February and December in 2016,and 20 healthy individuals were enrolled as controls.Patients received 6 weeks of rehabilitation guidance after operation,and the AEMG of VL,RF,and VM were evaluated before and 6 weeks after operation by sEMG(surface electromyography)analysis.Results1.The comparison between pre-operative uninjured limbs in ACL group and right limbs in healthy group: The differences of AEMG in VL(vastus lateralis),RF(rectus femoris),and VM(vastus medialis muscle)between them were all not significant(p>0.05).2.The difference between pre-operative injured and uninjured limbs in ACL group: The AEMG of VL,RF,and VM were all significantly lower in injured limbs than those in uninjured limbs(p<0.01).The AEMG decrease of RF was the lowest,whereas the decline of VM was the greatest.3.The change of pre-and post-operative injured limbs in ACL group: The injured limbs demonstrated significantly higher AEMG of VL,RF,and VM after operation(p<0.01).4.The comparison between post-operative injured and uninjured limbs in ACL group: Although the AEMG of VL,RF,and VM were increased in post-operative injured limbs,these values were still significantly lower than those in uninjured limbs(p<0.05).5.The change of VL:VM ratios in pre-and post-operative injured limbs: The ratios of VL:VM were significantly decreased after operation(p<0.01).6.The VL:VM ratios of pre-and post-operative injured limbs in ACL group were compared with those of left limbs in healthy group respectively: The ratios of VL:VM were both significantly higher in pre-and post-operative injured limbs than those in healthy controls(p<0.05).7.The Lysholm and VAS score of knee joints: The Lysholm score and VAS score were both decreased 6 weeks after operation,and the differences of them between preand post-operation were both significant(p<0.05).Conclusion1.The pre-operative uninjured limbs in ACL group demonstrate normal quadriceps strength.2.The quadriceps strength is decreased in pre-operative injured limbs.The AEMG decrease of RF is the lowest,whereas the decline of VM is the greatest.3.Quadriceps strength can be improved by post-operative rehabilitation but can't recover to normal in a short period of time.4.The training of the VM strength should be especially strengthened after operation.