Influence of screw length and diameter on tibial strain energy density distribution after anterior cruciate ligament reconstruction  

作　　者：Jie Yao Guan-Ming Kuang Duo Wai-Chi Wong Wen-Xin Niu Ming Zhang Yu-Bo Fan 

机构地区：[1]Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering/National Key Lab of Virtual Reality Technology,Beihang University [2]Interdisciplinary Division of Biomedical Engineering,Faculty of Engineering,The Hong Kong Polytechnic University [3]Shenzhen Key Laboratory for Innovative Technology in Orthopaedic Trauma,Department of Orthopaedics and Traumatology,The University of Hong Kong-Shenzhen Hospital [4]The University of Hong Kong [5]Tongji University School of Medicine

出　　处：《Acta Mechanica Sinica》2014年第2期241-249,共9页力学学报（英文版）

基　　金：supported by the National Science & Technology Pillar Program of China(2012BAI18B07 and 2012BAI22B02);the National Natural Science Foundation of China(10925208 and 11120101001);the National Key Lab of Virtual Reality Technology

摘　　要：Postoperative tunnel enlargement has been frequently reported after anterior cruciate ligament（ACL）reconstruction.Interference screw,as a surgical implant in ACL reconstruction,may influence natural loading transmission and contribute to tunnel enlargement.The aims of this study are（1）to quantify the alteration of strain energy density（SED）distribution after the anatomic single-bundle ACL reconstruction;and（2）to characterize the influence of screw length and diameter on the degree of the SED alteration.A validated finite element model of human knee joint was used.The screw length ranging from 20 to 30 mm with screw diameter ranging from 7 to 9 mm were investigated.In the post-operative knee,the SED increased steeply at the extra-articular tunnel aperture under compressive and complex loadings,whereas the SED decreased beneath the screw shaft and nearby the intra-articular tunnel aperture.Increasing the screw length could lower the SED deprivation in the proximal part of the bone tunnel;whereas increasing either screw length or diameter could aggravate the SED deprivation in the distal part of the bone tunnel.Decreasing the elastic modulus of the screw could lower the bone SED deprivation around the screw.In consideration of both graft stability and SED alteration,a biodegradable interference screw with a long length is recommended,which could provide a beneficial mechanical environment at the distal part of the tunnel,and meanwhile decrease the bone-graft motion and synovial fluid propagation at the proximal part of the tunnel.These findings together with the clinical and histological factors could help to improve surgical outcome,and serve as a preliminary knowledge for the following study of biodegradable interference screw.Postoperative tunnel enlargement has been frequently reported after anterior cruciate ligament（ACL）reconstruction.Interference screw,as a surgical implant in ACL reconstruction,may influence natural loading transmission and contribute to tunnel enlargement.The aims of this study are（1）to quantify the alteration of strain energy density（SED）distribution after the anatomic single-bundle ACL reconstruction;and（2）to characterize the influence of screw length and diameter on the degree of the SED alteration.A validated finite element model of human knee joint was used.The screw length ranging from 20 to 30 mm with screw diameter ranging from 7 to 9 mm were investigated.In the post-operative knee,the SED increased steeply at the extra-articular tunnel aperture under compressive and complex loadings,whereas the SED decreased beneath the screw shaft and nearby the intra-articular tunnel aperture.Increasing the screw length could lower the SED deprivation in the proximal part of the bone tunnel;whereas increasing either screw length or diameter could aggravate the SED deprivation in the distal part of the bone tunnel.Decreasing the elastic modulus of the screw could lower the bone SED deprivation around the screw.In consideration of both graft stability and SED alteration,a biodegradable interference screw with a long length is recommended,which could provide a beneficial mechanical environment at the distal part of the tunnel,and meanwhile decrease the bone-graft motion and synovial fluid propagation at the proximal part of the tunnel.These findings together with the clinical and histological factors could help to improve surgical outcome,and serve as a preliminary knowledge for the following study of biodegradable interference screw.

关 键 词：Anterior crucial ligament reconstruction Strain energy density Screw length Screw diameter 

分 类 号：R687.3[医药卫生—骨科学]