Preoperative Prediction Of Graft Diameter And Postoperative Graft Maturity Assessment For Anterior Cruciate Ligament Reconstruction Based On Magnetic Resonance Imaging(MRI)

First partQuantitative DWI and T2 mapping to evaluate the changes in graft maturity at 6 and 12 months after anterior cruciate ligament reconstructionBackground Grafts undergo a "maturity" process after anterior cruciate ligament reconstruction(ACLR)of the knee joint,and the degree of graft maturity affects the time a patient can return to sports after surgery.Quantitative MRI can detect the dynamic changes of water content and collagen fibers during graft maturation.Objective To quantify the status of graft remodeling using DWI and T2 mapping functional MRI at 6 and 12 months after anterior cruciate ligament reconstruction(ACLR)and its correlation with the corresponding clinical function score.Methods Patients(n=44 cases)who underwent ACLR from August 2020 to October 2021 and normal knee volunteers(n=21 cases)were collected prospectively 3.0T MRI routine sequence and DWI and T2 mapping scans were performed at 6 and 12 months.The ADC value and T2 value of the intra-articular segment of the graft and its three sub-segments(proximal,middle,and distal)were measured after surgery.IKDC,Lysholm clinical score.Results The ADC and T2 value of the proximal,middle,distal and entire intra-articular segment of the ACL graft decreased from 6 to 12 months after surgery(P<0.001).At each time point,there was no significant correlation with IKDC and Lysholm scores.At 6 months after operation,the ADC and T2 value of the distal segment of the intraarticular segment of the graft were higher than those of the proximal segment(P<0.001),while the ADC values of the three segments were similar in 12 months.Conclusion:DWI and T2 mapping can detect changes in the maturity of the intraarticular segment of the graft from 6 to 12 months after ACLR surgery.DWI and T2 mapping,as non-invasive quantitative imaging indicators for evaluating grafts,have potential clinical application value.The second partPreoperative MRI prediction of hamstring graft size in anterior cruciate ligament reconstruction of kneeBackground The diameter of the graft in anterior cruciate ligament reconstruction(ACLR)is an important factor for the refraction of the graft.Autologous tendon area measured on preoperative MRI was used to predict intraoperative graft diameter.Objective An anterior cruciate ligament graft diameter prediction model was constructed by measuring the cross-sectional area of the hamstring tendon(semitendinosus and gracilis)in preoperative knee magnetic resonance imaging.Methods MRI images of the knee were collected from patients(n=265)who underwent single-bundle anterior cruciate ligament reconstruction(ACLR)of 4 hamstring tendons at the Third Affiliated Hospital of Southern Medical University from January 2013 to August 2020;the cross-sectional areas of the semitendinosus tendon and gracilis tendon at the largest level of the femoral inner and outer condyles were measured.The relationship between the preoperative MRI-measured hamstring tendon cross-sectional area and intraoperative graft diameter was analyzed using correlation analysis,and the predictive value of popliteal cross-sectional area on intraoperative graft diameter was analyzed using the subject operating characteristic curve(ROC curve).Results In 136 patients with intraoperative graft diameter<8 mm,the mean crosssectional area of the semitendinosus tendon was 10.27±2.36 mm2,the mean cross,sectional area of the gracilis tendon was 5.33±1.70 mm2,and the mean cross-sectional area of the hamstring tendon was 15.60±3.66 mm2.129 patients with intraoperative graft diameter≥8 mm had a mean cross-sectional area of 13.66±2.99 mm2 for the semitendinosus tendon,7.73±2.12 mm2 for the gracilis tendon,and 21.40±4.58 mm2 for the hamstring tendon.The correlation coefficients between intraoperative graft diameter and cross-sectional area of gracilis tendon and semitendinosus tendon were 0.535(P<0.01)and 0.553(P<0.01),respectively.The subject’s area under the curve AUC was 0.838,and the optimal threshold for the cross-sectional area of the hamstring tendon measured on MRI for grafts greater than 8 mm was 19.97mm2.Conclusion:The hamstring cross-sectional area measured on preoperative knee MRI images can predict the diameter of intraoperative autologous hamstring muscle grafts.When the hamstring tendon cross-sectional area measured on MRI was greater than 19.97 mm2,the graft diameter was greater than 8 mm.