Study Of The Quadriceps Rehabilitation In The Early Postoperative Period After Anterior Cruciate Ligament Reconstruction Based On Flexible Deformation Electromyography Dual-mode Transducer

ObjectivePatients with anterior cruciate ligament(ACL)injuries and patients after anterior cruciate ligament reconstruction(ACLR)often suffer from quadriceps atrophy and strength loss.The quadriceps is an important muscle in maintaining the stability of the knee joint,so functional assessment and strength training of the quadriceps is important.This study aimed to observe the activity of the quadriceps during knee extension in patients with ACL injuries,and to compare three types of quadriceps rehabilitation exercises in the early postoperative period after ACLR to guide the rehabilitation of the quadriceps in patients with ACL injuries.MethodsForty patients who underwent ACLR surgery from December 2021 to March 2022 at Qilu Hospital of Shandong University were collected for general information.Knee extension in sitting position was performed before surgery using a flexible deformation electromyography dual-mode transducer,and electromyography(EMG)signals of rectus femoris,vastus medialis obliquus and vastus lateralis were collected at different knee extension angles.After ACLR,EMG signals of rectus femoris,vastus medialis obliquus and vastus lateralis were collected during quadriceps isometric contraction,straight leg raise for 5s,and straight leg raise for 10s.The subjective fatigue and pain levels were scored after training using a rating of perceived exertion(RPE)and a visual analogue scale(VAS).The EMG signals were processed using MATLAB software,and the integrated EMG(iEMG)values were calculated for each muscle.SPSS 23.0 statistical software was used for data analysis.Paired-samples t-test was used to compare the quadriceps EMG data,scale scores between the two knee extension phases and between the healthy and affected sides.One-way ANOVA was used to analyze the differences between groups in quadriceps EMG data and scale scores under the three rehabilitation exercises.A significant difference was considered at p<0.05 and a very significant difference was considered at p<0.01.Results1.iEMG of rectus femoris,vastus medialis obliquus and vastus lateralis during sitting knee extension 45°～0° were higher than 90°～45° knee extension in patients with ACL injuries on both the healthy and affected sides(p<0.01).During knee extension 90°～45°,the iEMG of vastus medialis obliquus was higher on the healthy side than on the affected side(p<0.05).The iEMG of rectus femoris,vastus medialis obliquus and vastus lateralis were higher on the healthy side than on the affected side during 45°～0° knee extension(p<0.05).2.In the 3 rehabilitation exercises in patients after ACLR,the balance of force generation and the degree of force generation of quadriceps during isometric contraction on the healthy side were significantly better than other rehabilitation exercises(p<0.01),while the balance of force generation and the degree of force generation of quadriceps during straight leg raise on the affected side were better than isometric contraction(p<0.01),and the stimulation effect of straight leg raise for 10s was better than that of straight leg raise for 5 s on the vastus medialis obliquus(p<0.01).The degree of quadriceps force generation during isometric contraction on the affected side was less than that on the healthy side(p<0.01),while the degree of quadriceps force generation during the 2 straight leg raises was slightly greater than that on the healthy side(p<0.01).3.In the fatigue assessment of the 3 rehabilitation exercises,the RPE of the 3 rehabilitation exercises on the affected side was greater than that on the healthy side(p<0.01);the RPE of isometric contraction was the lowest on both the healthy side and the affected side(p<0.01),and the RPE of straight leg raise for 10s was the highest(p<0.01).4.In the assessment of the pain level of the 3 rehabilitation exercises,the VAS of isometric contraction was the lowest on the affected side(p<0.01),and the VAS of straight leg raise for 10s was the highest(p<0.01).The VAS of all 3 rehabilitation exercises on the healthy side was 0.Conclusion1.The degree of quadriceps activity during sitting knee extension is related to the change in knee joint angle.ACL injury leads to a decrease in quadriceps activity,especially in vastus medialis obliquus and at the end of sitting knee extension(45°～0°).2.There was a difference between the affected side and the healthy side in quadriceps force generation during the early postoperative rehabilitation training.The straight leg raise for 10s has a better exercise effect on the affected quadriceps,especially on vastus medialis obliquus.3.A more relaxing training method,such as isometric contraction,can be chosen during early postoperative rehabilitation training to reduce the patient’s pain and psychological burden effectively.