The Anatomy Of The Anterior Cruciate Ligament And The Biomechanical And Clinical Study Of The Reconstruction Of The Anterior Cruciate Ligament

??Anatomical study and clinical value of the anterior cruciate ligament.Objective: To observed anatomic morphological features of tibial and femoral attachment and morphology of ACL and measure the length,horizontal diameter,anteroposterior diameter and the endure stress at different joint position of ACL.The study could provide more detailed anatomic data and mechanical parameters for the diagnosis and treatment of anterior cruciate ligament injury.Methods: The study is performed in 42 knee samples,provided by Department of Anatomy of Xiang Ya School of Medicine.All of them are from different specimens.The femurol and the tibial side end of the retention of the stump 10 cm long.Remove the skin,muscle,joint capsule and patella around the knee,and retain the lateral and medial collateral ligament,anterior and posterior cruciate ligament and the lateral and medial meniscus.ACL and its attachment are visible.The length of anteriomedialis and post lateral part of ligament,the width and thickness of the central part of 1igament were measured with vernier caliper.Flex knee joint passively,and observe the fiber tension variation of ACL during flexion and extension.Separate ACL from the upper of ACL along the fiber bundle to go up to down separately,end on the femoral and tibial attachment.Divide ACL into anteromedial bundle(AMB)and posterolateral bundle(PLB),and cut off AMB and PLB from the tibial and femoral attachment respectively.Then trace the contours of tibial and femoral attachment.We understand the change of these measure value and 1igament tension at different joint position and understand me structure of ligament and its adherent bone tissue with operation microscope,histological section and Micro CT.With the application of SPSS 13.0 Statistical Package for measurement data processing,all measurements ara recorded as Mean±Standard Deviation.Results: The observation shows that anterior cruciate ligament locates between facies medialis midst l/3 of femur lateral condyle and spinous process of tibia.Fiber slopes down from post-outside to antero-inside.The fiber interlace together.There is no well-defined fiber bundle in ACL.We can only divide it as AMB and PLB by their function artificially.The tibial insertion of ACL located at the side of the medial inrercondylar ridge,and the posterior margin of it did not exceed the highese place of intercondylar ridge.AMB located on the anteromedial side of footprint,and PLB located on the posterolateral side of footprint.The irregular shape of tibial attachment could be divided into reversed triangle,oval and quadrilateral.The femoral attachment of ACL located on the posterior part of the inside of lateral femoral condyle.The edges of it were near the distal and rear edge of cartilage.AMB located on the anteromedial side of footprint,and PLB located on the posterolateral side of footprint.The shapes of the femoral attachment were oval primarily.The fiber connects compactly with bones from some angle and direction,just 1ike adhesive disc.When the knee was extended,the fibers of ACL were parallel in sagittal plane,as a flat ribbon.The distal and posterior part of fibers of ACL on the femoral attachment loosed gradually with the increasing of bending angle,and rotated forward.When the knee was bended to 90°,the distal and posterior part of fibers of ACL on the femoral attachment began to lie distal and anterior to the ligament.The proximal and anterior fibers loosed a little at the same time.When the knee was bended over 90°to 130°,the distal and posterior part of fibers of ACL lay in the front of the ligament completely.All fibers of ACL were tight.ACL rotated along the sagittal plane from the side view as knee was flexing and extending.There were always two different function bundles.At about 60°,the two function bundles of ACL were most obvious in the middle-upper section of the ligament.While knee move from extend to flexion the tension of anteriomedialis part of ACL rises from lower to higher and the tension of post 1ateral part of ACL is down from higher to 1ower.Both of them tense alternately.The length of ligament is invariableness.The result of microscope and histological section and Micro CT is alike with these observations.Micro CT shows that the bone density of attachment point is lower.It also tells us that in usually the stress on ligament is lower.As we measure it,the length of anteriomedialis part of ACL is 32.06~38.68 mm and post lateral part of ACL is 15.01~20.27 mm.The wide of central part of ACL is 7.48~12.05 mm and the thick is 5.66~9.56 mm.Conclusions: ACL located between facies medialis of femur lateral condyle and spinous process of tibia.Both of the end of ligament stick with bones.Fiber slope down from post-outside to antero-inside and interlace together.ACL could be divided into AMB and PLB functional bundles according to different fibers of ACL in knee flexion and extension.It was accepted widely in the world.While knee move from extend to flexion the tension of anteriormedialis and post lateral part of ACL change alternately.The length of ligament is invariableness.The measurements of ACL could be used as the reference in ACL reconstruction.In Chinese the measure value of ACL is shorter and smaller than reportorial results abroad.??Biomechanics Research of Reconstruction of ACLObjective: To understand the biomechanical nature of normal ACL and to compare thebiomechanical nature of ACL in different reconstruction methods.Methods: The study is performed in 21 samples.All of them are from different specimens.The femurol and the tibial side end of the retention of the stump 20 cm long.Remove the skin,muscle,joint capsule and patella around the knee,and retain the lateral and medial collateral ligament,anterior and posterior cruciate ligament and the lateral and medial meniscus.The specimen is fixed on the biomechanical machine.Use INSTRON 8032 electro-fluid servo-fatigue tester to test fresh normal cadaver knee and measure the biomechanical nature of normal knee ACL.Fix femur and tibia at 100 mm torque and give a pushing stress on post-superior of tibia as 5N/S till l00 N.Then measure the loading displacement of tibia and loading strain of ACL while the knee is at 0°,30°,60°,90°and 120° position respectively.Divide samples into five groups.There are 7 samples in each group.Then we measure normal ACL,cutting down ACL,reconstruction with one and double strands in single tunnel and reconstruction with double strands in double tunnel respectively.Results: Under the loading as 50 N,the tibial loading displacement while the knee is at 0°: normal ACL 2.37±0.69 mm,cutting ACL 6.14±0.59 mm,single strands 2.69±0.28 mm,double strands with single-tunnel 2.49±0.39 mm and double strands with double-tunnel 2.41±0.50 mm.The displacement with the cutting down ACL is larger than other case,and the difference was statistically significant(P<0.001).Compared with the other four cases,the difference was not great(P>0.05).while the knee is at 30°,60°,90°and 120°,the displacement is similar to that is at 0°.The displacement was greatest while the knee is at 30°.The result of the comparison was the same when loading 100 N and 50 N,but the displacement value was greater than 50 N.The main contribution of ACL is to restrain the loading displacement of tibia.The value of displacement of cutting ACL knee is much more man intact ACL knee.It will return to normal after reconstruction both with single and double strands.Comparatively speaking,in loading displacement of tibia and loading strain of ACL the reconstruction with double strands has a better result than single strands.It is more similar to normal ACL in biomechanical nature.Conclusions: The main function of ACL is to restrain the loading displacement of tibia.The value will be much more while ACL is cut.Which is interfere the function of knee and should be rebuilt.Three reconstruction methods can recover the nature of ACL in restraining the loading displacement of tibia.Analyzing the loading strain of ACL,the double-tunnel reconstruction with double strands is more similar to normal ACL in functional anatomy and biomechanical nature.The single-tunnel reconstruction can also recover the function of ACL,and it is simpler and more widely used in clinic.??Analysis on clinical efficacy of autogenous hamstring tendon for arthroscopic anterior cruciate ligament(ACL)reconstructionObjective: To investigate the clinical efficacy of hamstring tendon for arthroscopic ACL reconstruction.Methods: From September 2014 to June 2015,42 patients with ACL injury have been treated with arthroscopic hamstrings graft reconstruction in our hospital consecutively.The position and degree of trauma is diagnosed by arthroscopy.At the same time we handle some complicated lesion.Prepare hamstring tendon for 18-24 cm through a small anterior incision of the knee.The hamstring graft was folded into quadrupled.Guarding by arthroscopy and locator,we find center point of tibia attaching site for making tibia tunnel and endostoma of femur for making femur tunnel.The endostoma of femur is at 11 o'clock at right knee and 1 o'clock at left knee,7mm to posterior wall.Then we draw the tendon into tunnels and make it to normal location and tension at genuflex30°and fix it with the endobutton and the absorbable screw,respectively.The anatomical structure and the biomechanical function of the ACL were restored.After operation,function exercise is carried out with the aid of the knee joint support.Avoid violent exercise for half year.Results: All of the 42 cases were followed-up for 3-18 months(average 9 months)after operation.All patients achieved healing by the first intention.The extension and flexion functions were restored to normal at 8-10 weeks.The results of drawer test and Lachman test were positive in 2 patients and suspiciously positive in 6 patients.Patients are evaluated by Lysholm knee score.Before operation their score are 28-71(40.57±10.68)and at the time of follow-up their score are 65-100(86.43±9.33),showing significant difference(P< 0.001).If we set scare 90-100 as excellent,80-89 as good,70-79 as fair and <70 as poor,there are 14 cases have excellent effect and 19 are good,5 are fair and 4 are poor.Conclusion: Reconstructing defected ACL by orthroscopy is an excellent technology with slight trauma and little complication.It is convenience and exact fixing,Patients can recover soon.During operation we can diagnose and treat some complicated lesion.Reconstructing ACL with hamstring tendon and fixing it with the endobutton and the absorbable screw can rebuild an excellent biomechanical nature to defected ACL and stabilize knee.The clinical effect is excellent.