骨科可吸收材料的降解和生物力学性能研究进展

降解和生物力学性能是可吸收材料的两个重要特性。虽然可吸收材料具有可降解、生物相容性好等优点，但根据目前可降解材料在骨科临床中的要求和应用情况，材料的降解速度和力学性能方面还需要进一步完善。文章综述了各类可吸收材料在骨科临床应用中的降解行为、降解过程中生物力学性能的变化，并展望了可吸收材料的前景。     

国外医用缝合线的发展状况

医用缝合线是一种用于伤口缝合、组织结扎和组织固定的无菌线,主要分为非吸收性缝合线和可吸收性缝合性二种。本文较全面介绍了国外医用缝合线的发展状况和高分子材料在医用缝合线上的应用,并比较了各种医用缝合线的特点。     

国外医用缝合线的发展状况

医用缝合线是一种用于伤口缝合、组织结扎和组织固定的无菌线，主要分为非吸收性缝合线和可吸收性缝合性二种。本较全面介绍了国外医用缝合线的发展状况和高分子材料在医用缝合线上的应用，并比较了各种医用缝合线的特点。     

可降解、可吸收性骨科材料类型及发展

综述了可用作可降解、可吸收性骨科材料的高分子材料、无机材料和复合材料 ,主要对聚乳酸、甲壳素和磷酸三钙等可降解吸收骨科材料的性质、用途等做了较为详细的阐述。并对可降解吸收骨科材料的发展趋势进行了探讨。认为各种材料之间的复合 ,特别是与骨形态发生蛋白以及骨髓基质干细胞之间的复合 ;现有材料的增强 ;寻找新的可降解可吸收材料将是可降解可吸收骨科材料的发展趋势     

可吸收缝线材料的可降解与临床应用

背景：由于可吸收缝合线具有良好的生物相容性及机械强度,在临床被广泛应用。 目的：探讨不同可吸收性缝线的体外降解性能,分析可吸收缝合线临床应用中的优势及其体外降解行为的影响因素。 方法：通过检索近年来文章内容与可吸收缝线材料降解性能和应用相关的文献,从可吸收缝线材料的性能及降解行为影响因素、可吸收与不可吸收缝合线临床应用比较等对可吸收缝线材料相关研究成果作回顾性分析,为临床提供理论依据。 结果与结论：可吸收缝合线体可被机体完全降解吸收,无不良反应,创口愈合后不留瘢痕,克服了不可吸收缝合线不能在体内分解的缺点,其降解产物的体内吸收主要有2个途径：一为体内巨细胞与吞噬细胞吞噬,另一途径为降解产物进入人的体液与血液,如乳酸通过体循环被吸收排泄。人体内有一个极其复杂的生理环境,存在着影响材料性能的各种因素。加之材料的种类不同,它们在体内的降解行为也不尽相同,因此需要在一定范围内设计合成和加工出具有特殊性能的可降解高分子材料满足临床需要。中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程全文链接：     

三种可吸收合成缝合线在犬胃和膀胱部位缝合的病理学观察

作者研究了ＴＨ、ＴＦ可吸收合成缝合线犬胃和膀胱部位后７、１５及２５天的组织学变化，并与美国ＰＤＳ可吸收合成缝合线进行比较。结果发现在胃部缝合７－１５天，ＴＨ呆吸收合成缝合线以纤维增生为主，炎性细胞较少，组织反应相对较轻，ＴＦ可吸收合成终究事线以炎性反应为主，纤维增生较轻；ＰＤＳ可吸收合成合线在胃部位缝合７天炎性细胞和纤维增生较明显，三各可吸收合成缝合线在膀胱部位缝合的炎性细胞和纤维增生均比胃部缝     

可吸收缝合线修复韧带运动性损伤及其材料学性质

背景：缝合技术的进步与发展为肌腱、韧带组织单位的撕裂或断裂治疗提供了保障,可吸收缝合材料的运用在更大程度上可以避免不可吸收缝合材料存在的治疗风险,正在普遍受到医患双方的青睐。 目的：分析可吸收缝合线的材料的材料学特征,探索在韧带损伤康复工程中的临床应用价值。 方法：由第一作者检索1990/2010 PubMed数据及万方数据库选择文章内容与软组织缝合治疗方法、材料学特点、生物相容性及其应用效果相关等方面的文献。 结果与结论：可吸收缝合线在体内可以降解成为可溶性产物,从而减小了患者二次手术的痛苦和尽量减小了患者缝合处瘢痕的形成,越来越受到医患双方的青睐,目前各种不同材料可吸收缝合线的出现,在一定程度上满足了人们的需求。     

组织工程软骨缝合技术及缝合材料的研究与进展

背景：软骨组织的生理特征及其功能结构特点表面,其受损后自我康复较难,根据其受伤特点及受损区域可以进行相应缝合,但缝线材料的选择尤为重要,随着可吸收缝线材料的研制与运用,为软骨组织缝合技术的运用提供了更大保障。 目的：文章综述了软骨组织生理特征,医用缝合线材料研究进展及其运用情况,着重介绍了可吸收缝线的材料学特征及其临床运用效果,指导临床合理选择材料和对新材料进行开发或研制。 方法：应用计算机检索CNKI和PubMed数据库中1993-01/2011-01关于软骨损伤及医用缝线材料的文章,在标题和摘要中以“软骨;缝合线;材料”或“Cartilage; Seam; materials”为检索词进行检索。选择文章内容与缝线材料相关,同一领域文献则选择近期发表或发表在权威杂志文章。初检得到193篇文献,根据纳入标准选择30篇文章进行综述。 结果与结论：软骨的生理特征制约着自我修复的效果,一般认为较难恢复,所以大多采用切除手术,但切除手术后期效果不理想,应尽量保留软骨组织,同时研究发现软骨组织周边区域具有一定的自我修复功能,所以对于规则性裂伤进行缝合康复,后期效果较好。但又由于软骨组织特殊的功能结构及需体内手术,所以不可吸收缝合线很难避免二次伤害及手术效果不理想,可吸收缝合线的出现为软骨组织的缝合康复及其缝合技术的发展提供了更大可能和保障,随着缝合技术的进步及新型材料的研制成功,软骨缝合作为一种组织工程修复手段将会得到逐步运用和改良。     

缝合线植入兔肌肉后的组织病理学观察

医用可吸收缝合线是一种用于伤口缝合，组织结扎和组织固定的无菌线。缝合组织后引起什么程度的炎症反应，缝合成周围组织有什么样的病理变化，可吸收合成缝线在体内被吸收的时间，都与缝合线的结合有关。我们用ＴＨ可吸收合成缝合成植入兔肌肉后５、３０、９０、１２０、１５０、１８０及２１０天做组织学观察，与美国Ｄｅｘｏｎ＇１１可吸收合成缝合成线进行了比较。     

拉伸法测Mersilk缝合线的力学性能

为了获得非吸收性Mersilk缝合线的力学性能,用JCD3型读数显微镜代替JC10型读数显微镜改进了FD-YC-II型杨氏模量测定仪,利用拉伸法测量1-0型Mersilk缝合线在加载、卸载时的轴向伸长量,得到了拉伸Mersilk缝合线的应力-应变曲线与滞后回线,测得Mersilk缝合线直径为（0.372±0.003） mm、拉伸强度为（320.87±4.64） MPa、断裂伸长率为（11.91±0.11）%、杨氏模量为（65.91±0.88） MPa,并测定了应力-应变滞后回线。实验结果表明,用FD-YC-II型杨氏模量测定仪测定手术缝合线力学性能的实验方法简单、结果可靠,可以为医学临床应用提供数据参考,也可用于医学物理实验教学。     

Nanoindentation of injection molded PLA and self-reinforced composite PLA after in vitro conditioning for three months

Poly(lactic acid) (PLA) is used for medical devices such as sutures or orthopedic screws. A standard way to determine the loss of mechanical properties of a degradable polymer would be to soak the polymer in phosphate buffered saline (PBS) and test the desired property as a function of immersion time. This method is not sensitive enough to discern changes in mechanical properties through the cross-section of the polymer and neglects the degradation that is occurring at the molecular level. This article presents results of a nanoindentation study carried out with PLA. The modulus and hardness of PLA is characterized as a function of processing method, immersion time in PBS, and location of the indent. Measuring local properties with the nanoindenter allowed detection of differences in material properties as a function of all three of these variables. The mechanical properties on the edge were lower than the interior of the sample after in vitro degradation, and changes were seen earlier for nanoindentation than for traditional flexural or tensile tests. The nanoindenter is a valuable tool for quantifying changes in material properties and may have applicability for accelerated tests to screen biomaterials.     

The application of polyhydroxyalkanoates as tissue engineering materials

Polyhydoxyalkanoates (PHA) are polyesters produced by microorganisms under unbalanced growth conditions. They are generally biodegradable and thermoprocessable, making them attractive as biomaterials for applications in both conventional medical devices and tissue engineering. Over the past years, PHA, particularly poly 3-hydroxybutyrate (PHB), copolymers of 3-hydroxybutyrate and 3-hydroxyvalerate (PHBV), poly 4-hydroxybutyrate (P4HB), copolymers of 3-hydroxybutyrate and 3-hydroxyhexanoate (PHBHHx) and poly 3-hydroxyoctanoate (PHO) and its composites have been used to develop devices including sutures, repair devices, repair patches, slings, cardiovascular patches, orthopedic pins, adhesion barriers, stents, guided tissue repair/regeneration devices, articular cartilage repair devices, nerve guides, tendon repair devices, bone marrow scaffolds, and wound dressings. The changing PHA compositions also allow favorable mechanical properties, biocompatibility, and degradation times within desirable time frames under specific physiological conditions. This paper reviews what have been achieved in the PHA tissue engineering area and concluded that the PHA prospective will look very bright in the near future.     

Preparation and characterization of sol-gel hydroxyapatite and its electrochemical evaluation for biomedical applications

Metallic materials having good mechanical properties, high corrosion resistance, and good compatibility with biological materials are used as orthopedic devices. Type 316L stainless steel is the most widely used material for implant fabrication in India for orthopedic applications owing to their good corrosion resistance, hot and cold workability, excellent mechanical properties, and availability at low cost. However, it faces corrosion-related problems in physiological environment and thus releases toxic metal ions into the tissues surrounding the implants. Hence, hydroxyapatite (HAP) coatings over the metal implant have been developed as an alternative method to improve the surface conditions of the base metal. In the present investigation, the development of a sol-gel-derived hydroxyapatite coating on 316L SS is being explored. The corrosion resistance behavior of the coating was assessed through electrochemical studies involving cyclic polarization experiments and impedance analysis in Ringer's solution. The results have indicated that the sol-gel-derived HAP coatings exhibited excellent resistance to localized attack on pristine 316L SS.     

Comparison of strength properties of poly-L/D-lactide (PLDLA) 96/4 and polyglyconate (Maxon) sutures: in vitro, in the subcutis, and in the achilles tendon of rabbits

Achilles tendon rupture is a common injury. Absorbable sutures are not commonly used because of their limited strength properties. Recently, sutures with prolonged strength retention properties have been developed. The aim of the study is to test the mechanical properties of recently developed poly-L/D-lactide (PLDLA) sutures in comparison with polyglyconate (Maxon) sutures. PLDLA (0.2 mm thick) and Maxon (4.0) sutures were studied in vitro by immersion in a buffered saline solution (pH 7.4). Tensile strength tests were done on sutures retrieved after 1-26 weeks. In vivo, they were implanted in the subcutis of 32 rabbits. Tensile strength tests were done on sutures retrieved after 1-6 weeks. The sutures were also used to repair the Achilles tendon in rabbits. Maximum force before breaking and percentage elongation of tendons were determined. Although PLDLA had a lower initial tensile strength than Maxon, PLDLA showed more prolonged tensile strength retention than Maxon. Tendons repaired with PLDLA, however, had a lower strength than Maxon-repaired tendons at six weeks (insignificant difference). PLDLA has more prolonged tensile strength properties compared with Maxon. Thus, PLDLA offers an alternative to Maxon in repair of the Achilles tendon.     

个性化骨植入医疗器械质量控制及技术评价研究

目的 对个性化骨植入医疗器械质量控制及技术评价提出相关建议,以期为监管机构和生产企业等相关人员提供指导和参考。方法 立足于个性化骨植入医疗器械的特点,依照医疗器械安全和性能的基本原则,汲取风险管理意识经验,为促进质量控制和技术评价的科学性,从法规体系建设、上市前研究和上市后监管等角度出发,对个性化骨植入医疗器械的质量控制和技术评价的关注点进行充分探讨。结果 个性化骨植入医疗器械的质量控制应重点关注机构和人员、设备、文件管理、设计开发等方面,技术评价应重点关注个性化骨植入医疗器械的基本特征和实际应用产品的技术评价。结论 建议完善个性化骨植入医疗器械指导文件的建设,深入个性化骨植入医疗器械上市前研究,加强个性化骨植入医疗器械上市后的监管。     

Medical devices in orthopedic applications

Orthopedic medical devices have been extremely successful in restoring mobility, reducing pain, and improving the quality of life for millions of individuals each year. Their success is reflected in the worldwide biomaterials market, in which orthopedic devices dominated sales at approximately $14 billion in 2002. Of this, approximately $12 billion was spent on joint replacements. In spite of their overwhelming benefits and successes, orthopedic medical devices are not without risk of adverse effects. Most adverse joint replacement outcomes are thought to be mediated by degradation products generated by wear and electrochemical corrosion. Infection and flaws in device manufacturing are other noteworthy causes of orthopedic device failure. This article illustrates and discusses the uses, general properties, and limitations (including adverse outcomes) of orthopedic biomaterials, which are fundamental to understanding requirements for improving current orthopedic medical devices.     

Effect of different sterilization processing methods on the mechanical properties of human cancellous bone allografts

Use of new sterilization methods applied to human bone is likely to affect both the mechanical and biological properties of human cancellous grafts. The mechanical properties of the transplanted bone inevitably determine the short- and mid-term results of the orthopedic procedure performed. The aim of this study was to compare, under similar conditions, the mechanical effects of gamma irradiation, lipid extraction, and treatment with 6M urea on trabecular bone samples, through conventional mechanical tests and measurement of the ultrasound wave propagation rate. Deteriorations measured for gamma irradiation and lipid extraction were low: 2.4% and 2.5%, respectively, for ultrasound propagation wave measurements. They were clearly significant for protocol including 6M urea, corresponding to a loss of 30% in values measured in the control sample for the stress to failure, inciting prudence when grafted bone is used for support in orthopedic assembly. High consistency in the results obtained between travel time of the ultrasound wave, easily done, and measurement of stress to failure through conventional tests, favor the use of ultrasound protocol, described as a quality test performed on bone grafts in the tissue bank before distribution and implantation.     

Tensile properties of suture materials

The tensile properties of three new sutures, two non-absorbable and one absorbable material, have been evaluated and compared with those of polypropylene and nylon sutures. It was found that the five materials differed significantly in their tensile strengths and elastic/plastic deformation characteristics but displayed comparable elongations at failure. All sutures showed a decrease in failure load and elongation at failure when knotted. Most materials showed an increased tensile strength and decreased elongation at failure for smaller suture gauges, and this behaviour is thought to be related to their internal molecular organization.     

Composites of poly(DL-lactide-co-glycolide) and calcium carbonate: in vitro evaluation for use in orthopedic applications

Biodegradable materials utilized in current orthopedic sports medicine fixation devices are required to maintain mechanical properties for at least 12 weeks to facilitate tissue healing and then ideally degrade with eventual replacement by surrounding tissue (bone). Current materials exhibit excessive longevity, which limit the potential for bone replacement, an ideal outcome in clinical procedures where revisions are a possibility. This study investigates material property modification of poly(DL-lactide-co-glycolide) (PLGA) by calcium carbonate. Modification of the degradation rate of PLGA by calcium carbonate (16, 36, 51% w/w) was demonstrated and the percentage of calcium carbonate within the polymer optimized at 36% (w/w). The optimized formulation was molded into a fixation screw and in vitro degradation demonstrated a gradual loss in molecular weight but with a pull-out strength retention beyond 12 weeks. Significant mass loss then occurred after 26 weeks. Physical testing, insertion torque, and failure torque indicated that this composite also had sufficient initial mechanical properties required for screw in type fixation devices. The combination of mechanical properties and degradation behavior suggests that this material may have potential to be utilized in orthopedic fixation devices that are placed in bone.     

Development and characterisation of silver-doped bioactive glass-coated sutures for tissue engineering and wound healing applications

A novel silver-doped bioactive glass powder (AgBG) was used to coat resorbable Vicryl (polyglactin 910) and non-resorbable Mersilk surgical sutures, thereby imparting bioactive, antimicrobial and bactericidal properties to the sutures. Stable and homogeneous coatings on the surface of the sutures were achieved using an optimised aqueous slurry-dipping technique. Dynamic mechanical analysis (DMA) was used to investigate the viscoelastic parameters of storage modulus and tandelta and thermal transitions of the as-received and composite (coated) sutures. The results generally showed that the bioactive glass coating did not affect the dynamic mechanical and thermal properties of the sutures. The in vitro bioactivity of the sutures was tested by immersion in simulated body fluid (SBF). After only 3 days of immersion in SBF, bonelike hydroxyapatite formed on the coated suture surfaces, indicating their enhanced bioactive behaviour. Resorbable sutures with bioactive coatings as fabricated here, in conjunction with 3-D textile technology, may provide attractive materials for producing 3-D scaffolds with controlled porosities for tissue engineering applications. The bactericidal properties imparted by the Ag-containing glass coating open also new opportunities for use of the composite sutures in wound healing and body wall repair.