| Background:Anterior Cruciate ligament(ACL)is an important structure which resists anterior tibial translational and tibil internal rotation in knee joint.ACL rupture is a common sports medicine injury,its main injury mechanism for excessive axial stress and torsional shear stress caused by tibial abnormal forward and internal rotation,cause anterior cruciate ligament continuity interruption,at the same time can be accompanied by meniscus tear,articular cartilage edema injury.Clinical arthroscopic ACL reconstruction is currently recognized surgical treatment.The goal is to restore the stable structure of the knee joint as much as possible,prevent the aggravation of joint instability,cause secondary injury,avoid further injury of articular cartilage and meniscus,and reduce the risk of secondary early osteoarthritis,and finally help patients to recover their sport ability and and sport level.After more than 20 years of development,ACL reconstructive surgery has been relatively mature.However,many clinical satisfaction and postoperative return to movement of ACL reconstruction are not satisfactory,among which graft failure and residual instability of knee joint caused by the deviation of bone tunnel position during operation are the main factors of ACL reconstruction failure.For the intraoperative positioning of the bone tunnel,the subjective choice of the surgeon has a large error,while the use of traditional locators is greatly influenced by the diameter of the graft muscle tendon,so an individualized surgical method is needed to be studied to achieve accurate anatomical ACL reconstruction.For a long time,Computed Tomography(CT)is difficult to get the satisfied images in ligament and tendon,but Dual-Source Computed Tomography(DSCT)has the characteristics of fast imaging,high resolution and stereoscopic visual display for soft tissue.This study attempts to expand the function of DSCT in ACL graft imaging,study the relationship between ACL graft position and bone tunnel placement after surgery,determine the anatomy of ACL reconstruction,and provide a theoretical basis for further research for surgical evaluation criteria,improvement of bone tunnel locationing technology,and achieve personalized and accurate anatomical reconstruction of ACL.Objective:Study 1:In this research attempted to use DSCT in imaging of the graft after ACL single-bundle reconstruction.Study 2:To three-dimensionally document ACL graft and evaluate graft position and the tunnel placement after single-bundle ACL reconstruction with DSCT,and explore its clinical application value.Study 3:To compare the efficacy of DSCT-assisted ACL anatomical single-bundle reconstruction and conventional ACL anatomical single-bundle reconstruction.methods:Study 1:DSCT was used to scan 35 patients diagnosed as ACL injury who underwent arthroscopic single-bundle reconstruction of ACL,reconstruct the image of ACL grafts,and analyze the image quality.Study 2:A total of 123 patients who underwent arthroscopic ACL single-bundle reconstruction in Orthopaedic Department of Maanshan People’s Hospital from January 2017 to October 2021 were scanned by DSCT within one week,and divided into"impingement group"(n=35),"too posterior group"(n=37),"good group"(n=51).Graft position and tunnel placement were evaluated,femoral tunnel position(Fx、Fy,Bernard quadrant method),tibial tunnel position(Tx、Ty,Lorenz method),graft length(L),angles in sagittal plane(∠α)and coronal plane(∠β)were measured and compared subsequently.Study 3:A retrospective analysis was performed for arthroscopic single-bundle ACL reconstruction of 55 patients with ACL rupture using autologous tendon in orthopedic Department of Maanshan People’s Hospita from June 2020 to December 2021.The 28 cases using conventional ACL anatomical single bundle reconstruction method were in the conventional group,including 17 males and 11 females with the mean age of 30.75±8.41 years(range,18-48 years);27 patients with DSCT assisted ACL reconstruction were DSCT group,19 males,8 females,with the mean age of 31.96±8.92 years(range,17-49 years).Lysholm score and IKDC score were used to evaluate the knee joint function,Lachman test,Front drawer test and Pivot-shift test were used to evaluate the knee joint forward and rotational stability,and Howell grading method of Magnetic Resonance Imaging(MRI)was used to evaluate the postoperative ACL graft healing status,and the difference between the two groups was compared.And apply DSCT scan to compare the placement of postoperative bone tunnel and preoperative circle marks to evaluate the accuracy of tunnel location assisted by DSCT.Results:Study 1:All 35 grafts were successfully imaged by DSCT with our technique and scanning parameters,of which 33 had clear graft images and 2 had unclear graft images,and the graft image score was 5.6769±0.8638.Study 2:In impingement group,femoral tunnel position descriptive Fxl,Fy1 was 22.72± 1.21%,22.92± 1.72%respectively in average;tibial tunnel position descriptive Txl,Tyl was 53.29± 1.68%,38.49±3.65%respectively in average;the graft descriptive L1,∠α1 and ∠β1 was 26.86±1.27mm,9.17±0.65° and 9.54±1.19° respectively.In too posterior group,femoral tunnel position descriptive Fx2,Fy2,was 22.11± 1.34%,23.24± 1.40%respectively in average;tibial tunnel position descriptive Tx2,Ty2 was 56.59± 1.00%,53.50±2.85%respectively;the graft descriptive L2,∠α2 and ∠β2 was 27.40± 1.39mm,7.66±0.72° and 8.17±0.71° respectively.In good group,femoral tunnel position descriptive Fx3,Fy3 was 22.42±1.27%,22.97±1.68%respectively in average;tibial tunnel position descriptive Tx3,Ty3 was 56.90± 1.19%,46.17±4.33%respectively;the graft descriptive L3,∠α3 and ∠β3 was 27.04± 1.38mm,8.53±0.40°and 78.55±0.66° respectively.Statistic analysis showed that there was no significant difference(P>0.05)between any groups at Fx,Fy and L,but significant difference(P<0.05)was found in three groups at Tx,Ty and ∠α,∠β.Tx,Ty and ∠α were independent risk factors for impingement between the graft and the intercondylar roof,and Ty and ∠α were independent risk factors for posterior deviation of the tibial tunnel.Study 3:The mean preoperative Lysholm score of patients in the conventional group was 46.37±4.05,increased to 80.33±5.13 at 3 months after surgery,The Lysholm score at 6 months and 12 months after surgery were 85.00±3.90 and 87.41±3.31 respectively;The mean preoperative Lysholm score of patients in the DSCT group was 46.85±3.61,Increased to 79.93±4.34 at 3 months after surgery,The Lysholm score at 6 months and 12 months after surgery were 86.67±4.18 and 88.44±3.50 respectively.The mean preoperative IKDC score of patients in the conventional group was 37.61 ±3.42,Increased to 79.46±5.10 at 3 months after surgery,The IKDC scores at 6 months and 12 months after surgery were 84.93±4.18 and 87.64±3.20 respectively;The mean preoperative IKDC score of patients in the DSCT group was 38.74±4.10,Increased to 79.26 ± 4.25 at 3 months after surgery,The IKDC scores were 85.48±4.06 and 88.44±3.20 at 6 and 12 months after surgery,respectively.The Lysholm knee score and ICDC scores were higher at 3,6,and 12 months after surgery(P<0.05);There was no significant difference between the two groups(P>0.05).Comparing the Lachman test,anterior drawer test and Pivot-Shift test before and after surgery,the Postoperative group was better than the preoperative group(P<0.05),and the DSCT group was better than the conventional group(P<0.05).At the follow-up of 12 months after surgery,the proportion of grade Ⅰ in the conventional group was 46.4%;The proportion of grade Ⅰ in DSCT group was 77.8%,and the proportion of Howell grade Ⅰ in DSCT group was significantly higher than that in conventional group(P<0.05).After postoperative review,the bone tunnel located by DSCT was in good position,basically in line with the preoperative design,and was very close to the original anatomical footprint.conclusion:Study 1:The graft of ACL single-bundle reconstruction can be documented clearly by DSCT with certain scanning technique and parameters which we recommended.It is of great value to study the anatomy of ACL and the biomechanics of ACL deeply.Study 2:DSCT can clearly evaluate the graft position and bone tunnel placement after single-bundle reconstruction of ACL and analyze risk factors causing graft collision and posterior deviation of bone tunnels.Briefly speaking,DSCT contributes to guiding the accurate preoperative positioning and postoperative evaluation.Study 3:ACL individualized single bundle anatomical reconstruction with DSCT is more close to the ACL anatomical footprint,anterior and rotational stability of postoperative knee is better,ACL graft healing is good,and the clinical efficacy is satisfactory. |
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