前十字韧带损伤是常见的膝关节运动损伤.目前的常规治疗方案是在关节镜下取自体髌韧带或腘韧带植入胫骨、股骨骨隧道,用内植物加强固定,重建前十字韧带功能.界面螺钉是重建前十字韧带的常用固定器械.理想的界面螺钉材料应满足坚强的固定强度并能长时间维持,促进骨性愈合或腱骨愈合的生物活性.界面螺钉材料包括金属材料和可吸收高分子聚合物材料两类.金属界面螺钉提供的固定强度及固定刚度高,但需二次手术取出;可吸收高分子聚合物界面螺钉不用二次手术取出,但力学强度低,降解过程中可能诱发无菌性炎症反应,出现螺钉松动、骨道变宽等并发症.镁金属界面螺钉是一种新型的可降解界面螺钉,已逐渐广泛应用于前十字韧带重建的固定.镁为人体必需营养元素,镁金属材料植入体内生物相容性良好,可促进骨质长入与矿质沉积,同时激活纤维软骨止点再生,在关节腔内不会诱发严重的炎症反应;体外与动物模型研究均证实其力学强度和刚度远高于高分子聚合物材料,接近骨皮质;且体内降解速率可通过合金工艺进行调控.%The anterior cruciate ligament (ACL) injury in sports is a common knee joint injury.It is widely accepted to reconstruct ACL under arthroscopy with autologous patellar ligament or popliteal ligament fixed in tibial or femoral tunnel with interference screws.Interference screws are widely used as intra-articular fixation devices in ACL reconstruction.The ideal materials for interference screw provide rigid fixation of graft with high mechanical strength,long-lasting stiffness and the bioactivity to stimulate osteointegration and tendon-bone healing.Current interference screws are made of metals and bio-absorbable polymers.Metallic interference screws provide high mechanical strength and stiffness for tendon graft fixation,but require a second surgery for removal.Bioabsorbable interference screws made of polymers avoid second surgery for removal,but have lower mechanical strength and might cause aseprtic inflammation during its degradation as well as screw slip,tunnel enlargement and many other complications.Magnesium (Mg) has been investigated as a novel and potential biomaterials for biodegradable interference screws.Mg is essential nutrient element and has good biocompatibility.Its mechanical strength and related stiffness are much higher than that of biodegradable polymers and are close to cortical bone.Furthermore,the degradation rate of Mg in vivo could be modulated via techniques such as alloying.In previous studies,the relationship between screw design and its pull-out force has been investigated,based on which the design of interference screw is optimized.The mechanical properties (the ultimate load to failure and the related stiffness) of interference screws proved to be higher than that of bioabsorbable interference screws sharing the same design both in vitro and in vivo.Furthermore,Mg performs good biocompatibility without severe intra-articular inflammatory reactions,as well as unique bioactivities to promote osteointegration,mineral deposition and the regeneration of fibrocartilaginous entheses.The present study reviews the researches of Mg interference screws both in vitro and in vivo,gives reference for further research and has great importance for the application of Mg interference screws in ACL reconstruction.
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