不同异体皮质骨板桥接股骨缺损的实验研究

[目的]观察冷冻组、酒精组、新鲜组异体皮质骨板桥接兔股骨缺损处的生物力学、影像学及组织学变化的差异。[方法]将制备好的冷冻、酒精储存和新鲜异体皮质骨板分别植入随机分组的3组大白兔股骨缺损处，植入后4、8、12周取材，从生物力学、影像学及组织学方面分析3种异体皮质骨板在兔体内的生物学变化过程。[结果]术后4周冷冻、酒精、新鲜组弯曲应力及位移相近，8、12周前2组较新鲜组有很大差异。术后12周冷冻、酒精组X线片均见异体皮质骨与宿主骨融合一体，新鲜组则未见融合。术后4周冷冻、酒精组出现成骨细胞，新鲜组未见；术后8周冷冻、酒精组有连续排列的成骨细胞，新鲜组仅见少量不连续的成骨细胞；术后12周冷冻、酒精组见大量连续排列的成骨细胞，新鲜组仅见排列连续的成骨细胞。[结论]冷冻、酒精储存异体皮质骨板和新鲜异体皮质骨板均具有初期生物力学的支撑功能；酒精储存异体骨板和冷冻异体骨板均能达到宿主骨-异体骨融合，而新鲜异体骨板由于免疫排斥反应其宿主骨-异体骨愈合能力较差。     

深低温冷冻异体肌腱移植的组织学和生物力学研究

[目的]探讨深低温冷冻同种异体肌腱替代自体肌腱进行移植治疗肌腱缺损的可行性及移植后异体肌腱的形态学和生物力学性能的动态变化.[方法]采用兔跟腱缺损修复模型,经深低温冷冻的同种异体跟腱为实验组.自体跟腱移植为对照组,分别在术前及术后2、4、8周时对实验组同种异体跟腱及对照组自体跟腱进行大体观察、组织学检查和生物力学测试.[结果]同种异体跟腱与自体跟腱在移植前和移植后2、4、8周时其大体观察、组织学检查和生物力学测试等各项指标均无明显差异,显示同种异体跟腱和自体跟腱有相类似的结构及愈合过程.另外,同种异体跟腱在移植后其力学性能(除衰竭应变外)均比移植前明显降低.随时间推进有上升的趋势,但8周时仍明显低于移植前水平.[结论]深低温冷冻同种异体肌腱可替代自体肌腱应用于移植修复肌腱缺损.同时,由于移植后肌腱力学性能明显下降,需给予适当保护,防止过度牵拉而导致衰竭.     

骨髓间充质干细胞促进骨-肌腱结合部位早期愈合的动物生物力学实验研究

[目的]通过生物力学研究,观察骨髓间充质干细胞对骨-肌腱结合部愈合的影响.[方法]采用骨髓穿刺、全骨髓培养法获取兔骨髓间充质干细胞.24只18周龄新西兰大白兔随机分为2组,实验组将骨髓间充质干细胞与Pluronic F-127载体材料结合后,植入兔髌骨部分切除模型,对照组只进行手术,不植入细胞.在术后6、12、18周处死动物取标本(n=4)进行生物力学检测评估骨-肌腱结合部位的愈合恢复情况.[结果]生物力学结果显示相同时间点实验组拉断负荷及极限拉应力均大于对照组,差异有统计学意义(P<0.05),提示实验组恢复较对照组迅速.[结论]相同时间点实验组拉断负荷、极限拉应力均大于对照组.实验组的力学特性明显高于对照组.骨髓间充质干细胞可以促进骨-肌腱结合部细胞早期愈合,提高其力学特性.     

补肾密骨片结合骨髓移植对桡骨延迟愈合的实验研究

[目的]观察补肾密骨片结合经皮自体骨髓移植对骨折延迟愈合治疗后的骨密度和生物力学性能影响。[方法]预制新西兰大耳白兔骨延迟愈合模型，将75只兔随机分为四组：A组20只，饲料中加入补肾密骨片，骨延迟愈合区注入自体红骨髓2ml；B组20只，饲料中加入补肾密骨片，骨延迟愈合区不注入自体红骨髓；C组20只，饲料中不加补肾密骨片，骨延迟愈合区注入自体红骨髓；D组15只，造成骨延迟愈合模型后，饲料中不加补肾密骨片，骨延迟愈合区不注人自体红骨髓。治疗后12周处死动物取材，行骨密度及生物力学测试。[结果]骨密度及生物力学测试均显示A组骨愈合优于B、C、D组。[结论]补肾密骨片结合经皮自体骨髓移植治疗骨折延迟愈合的骨组织的骨密度及生物力学强度优于单一骨髓移植或中药治疗。     

骨髓间充质干细胞及其复合物修复兔桡骨缺损的实验研究

[目的]通过新西兰大白兔骨髓间充质干细胞离体培养后与去抗原牛松质骨复合植入新西兰大白兔桡骨缺损处，比较修复节段性桡骨缺损的效果，初步探讨治疗骨缺损的组织工程学方法。[方法]新西兰大白兔骨髓间充质干细胞（MSCs）离体培养、纯化、扩增后在等同于细胞培养的条件下与去抗原牛松质骨（BCB）复合培养，制成MSCs／BCB复合物并经电镜扫描证实复合物有细胞生长。制成同种异体新西兰大白兔桡骨干15mm节段性动物模型，MSCs／BCB复合物通过手术移植入动物模型桡骨缺损处，通过X线放射学、组织学、生物力学检测对比实验组与对照组、空白组骨缺损修复情况。[结果]术后2、4、8、12、16周实验组与实验对照组放射学检查评价新骨生成有显著性差异（P〈0．01）。术后组织学检查新骨生成速度、生成量均有显著性差异（P〈0．01）。16周生物力学三点抗弯曲实验载荷、弯曲应力检测，实验组与实验对照组新骨生成有显著性差异（P〈0．01），实验组标本与正常基本一致。空白对照组各时点均无新骨形成，最后缺损由纤维组织充填。[结论]骨髓间充质干细胞（MSCs）是骨组织工程中适宜的种子细胞。去抗原牛松质骨能够与兔骨髓间充质干细胞体外复合培养，移植入异体新西兰大白兔后未见明显免疫排斥反应，是可以选择的细胞载体。MSCs／BCB复合物植入修复兔桡骨缺损能够加速新骨形成，修复效果明显优于单纯BCB植入。     

组织工程化人工骨修复骨缺损的实验研究

[目的]观察兔骨髓基质细胞与生物活性玻璃联合培养构建的组织工程化人工骨修复兔桡骨缺损的效果,探讨组织工程化人工骨促进骨缺损修复的作用机制.[方法]体外分离培养兔的骨髓基质细胞,经过传代扩增后,与生物活性玻璃联合立体培养构建组织工程化人工骨后,植入兔桡骨缺损处.通过大体形态观察、影像学、组织学、扫描电镜检查及生物力学分析,分别与单纯植入生物活性玻璃、髂骨以及空白组进行对比,观察各组对骨缺损修复的效果.[结果]植入组织工程化人工骨的兔桡骨缺损完全愈合,成骨效果与自体髂骨相似明显优于其他组.[结论]骨髓基质细胞复合生物活性玻璃构建的组织工程化人工骨能很好的完成骨缺损的修复.     

计算骨丧失量经椎弓根打压植骨治疗胸腰椎压缩性骨折的生物力学研究

[目的]探讨用计算骨丧失量的方法经椎弓根打压植骨(transpedicular impacted grafting,TPIG)治疗胸腰椎压缩性骨折的生物力学性能。[方法]将6具成人新鲜尸体胸腰椎标本,模拟正常组、压缩性骨折损伤组、单纯计算骨丧失量TPIG和单纯经椎弓根植骨组(transpedicular grafting,TPG)、计算骨丧失量TPIG+椎弓根固定和TPG+椎弓根固定组,行生物力学实验应力分析,比较各组的椎体和椎间盘的强度、刚度和稳定性以及扭转生物力学性能。[结果](1)计算骨丧失量TPIG+椎弓根固定组的椎体和椎间盘的强度、刚度和稳定性高于TPG+椎弓根固定组,具有显著性差异(P0.05);(2)单纯计算骨丧失量TPIG组的强度和刚度高于单纯TPG组,并具有显著性差异(P0.05);(3)从扭转生物力学试验中也同样得到了相似的结论。[结论]计算骨丧失量TPIG+椎弓根固定治疗胸腰椎压缩性骨折具有优越的生物力学性能,适合于临床应用。     

一氧化氮调节骨折愈合的实验研究

[目的] 探讨一氧化氮在骨折愈合中的可能作用。[方法] Wistar大鼠60只随机分为实验组和对照组。两组动物的饮用水分别含L-硝基-精氨酸甲基脂（L-NAME）和D-硝基-精氨酸甲基脂（D-NAME），建立股骨开放骨折模型，骨折后第3d、1、2和4周，取每组6只大鼠骨折处骨痂行HE染色观察。另6只大鼠于骨折后4周行骨痂的面积、骨密度和骨折的生物力学评价。[结果] 骨折后两组大鼠体重增加无差别。HE染色光镜下见骨折后不同时期L-NAME组骨折处骨痂生成少，骨痂塑形慢，未成熟细胞比例较对照组多（P〈0．05），加入L-NAME后使骨折愈合反应减小，实验组骨痂的大小、骨密度和愈合强度均明显低于对照组，有明显的统计学意义。[结论] 在骨折愈合过程中加入L-NAME会使骨折愈合减慢，一氧化氮可能促进骨折的愈合过程。     

不同内固定方法治疗踝关节后侧骨-韧带损伤的生物力学及有限元研究

[摘要]目的：通过标本生物力学和有限元分析的方法，比较分析不同的手术方法对踝关节旋前外旋Ⅳ度损伤后踝关节稳定性恢复的影响，并比较各手术方法之间是否存在差异。方法：随机选取6具成人新鲜小腿-足标本，去除踝周及以上软组织，保留踝周韧带和骨间膜。     

间充质干细胞体内成骨的实验研究

[目的]探讨间充质干细胞在体内的成骨能力。[方法]从羊髂嵴处抽取10～15ml骨髓组织，用Pereoll分离液按梯度离心法分离出间充质干细胞，培养、增殖后种植在多孔β-磷酸三钙上，构建组织工程化骨，植入8只羊的左后肢跖骨缺损区（长21mm）作为实验组；单纯植入多孔β-磷酸三钙陶瓷材料的8只羊作为对照组；分别在术后6、12、24周处死动物行放射学、组织学和生物力学检测。[结果]放射学和组织学检测，术后6周实验组即可见有新骨生成，对照组则无明显新骨生成；骨缺损部位新生骨样组织、编织骨和板状骨出现的时间实验组也都较对照组早，并且不经软骨介导即能直接成骨，而对照组从两端以“爬行替代”方式成骨。术后24周，放射学和生物力学检测显示实验组骨缺损几乎完全修复，对照组只有部分愈合。[结论]间充质干细胞不仅在体外具有良好的增殖能力，回植人体内后仍然具有良好的成骨能力，不需经过软骨过程就能直接形成新骨，显示了间充质干细胞作为骨组织工程种子细胞良好的应用前景。     

Structural properties of reconstruction constructs for the interosseous ligament of the forearm

PURPOSE: The Essex-Lopresti fracture-dislocation, also termed longitudinal radioulnar dissociation (LRUD), results in major functional impairment from pain and limitation of motion at the wrist and elbow. Interosseous ligament (IOL) reconstruction has been proposed to help treat LRUD and restore forearm stability. The objective of this study was to evaluate the biomechanical structural properties of 3 different IOL reconstruction constructs and of the intact IOL for comparison. METHODS: Structural tensile testing was performed on 24 fresh-frozen cadaveric forearms with 4 different forearm conditions: IOL intact and IOL reconstructed with Achilles tendon, flexor carpi radialis (FCR) tendon, and bone-patellar tendon-bone. Isolated radius-IOL-ulna constructs were loaded to failure in a materials testing machine with force applied along the local fiber direction. RESULTS: Stiffness in the intact IOL was 129 +/- 31 N/mm, which was significantly stiffer than any of the constructs tested. The intact IOL was 8 times stiffer than the Achilles tendon construct, 7 times stiffer than the FCR construct, and 3 times stiffer than the bone-patellar tendon-bone construct. The Achilles tendon and FCR constructs were similar to each other biomechanically but the bone-patellar tendon-bone construct was slightly stiffer than the Achilles tendon and FCR constructs. CONCLUSIONS: All graft constructs tested were inferior structurally to the intact IOL. The results of this study provide a biomechanical basis for graft selection for reconstruction of the IOL.     

Achilles tendon healing: A correlation between functional and mechanical performance in the rat

The pathogenesis and treatment of rupture of the Achilles tendon remain a source of controversy. This study presents the results of a biomechanical, functional, and morphological evaluation of a group of rats that had division and repair of the Achilles tendon. A total of 46 rats were used: 18 for biomechanical testing, 18 for functional evaluation, and 10 for histology. Morphological examination revealed an early inflammatory response with loose connective tissue formation that was replaced gradually by fibroblasts and a collagenous matrix. The functional evaluation (Achilles functional index [AFI]) was made from measurements of the hind pawprints of walking rats. Division and repair of the Achilles tendon produced a significant functional impairment (mean [±SEM] AFI = ?87 ± 8; p < 0.001), which gradually improved with healing time. The load to failure for the repaired tendons consistently improved with healing time, in a manner similar to the functional recovery. The average deformation (repair/control) varied considerably and was not related to healing time. The stiffness of the repaired tendons increased with healing time and was 60% of the corresponding control side by day 15. The major finding of this study was a strong correlation between the AFI and the failure load of the healing tendon-bone constructs (250–300 g group, r = 0.97, p < 0.001; 325–375 g group, r = 0.96, p < 0.001).     

Effects of immobilization on achilles tendon healing in a rat model

The aim of this study was to evaluate the effects of immobilization and mobilization on the functional and biomechanical recovery of injured Achilles tendons. Male Sprague-Dawley rats were allocated randomly into four groups: (a) sham operation, (b) division only (surgical transection of the Achilles tendon without immobilization), (c) “dummy” external fixation (division of the Achilles tendon and application of Kirschner wires), and (d) rigid external fixation (division of the Achilles tendon and immobilization with Kirschner wires connected by two triangular frames). All procedures were performed on the right lower limb; the left, uninjured, lower limb served as an internal control. Kirschner wires and external fixators were removed on day 12. Functional performance was determined from measurements of hind pawprints of rats walking preoperatively and on postoperative days 1, 3, 5, 7, 9, 11, 13, and 15. On day 15, the animals were killed and biomechanical evaluations were performed on both the injured and the uninjured Achilles tendon constructs. No functional or mechanical deficits were observed in the sham-operation group. Animals subjected to division of the Achilles tendon had an initial functional deficit that returned to near normal by day 15. The application of Kirschner wires was associated with an impairment of the functional performance of the rat as well as of the mechanical properties of the tendon-bone constructs. Immobilization by connection of the Kirschner wires to an external frame had an additional, highly significant (p < 0.001) detrimental effect on the functional and mechanical recovery of Achilles tendon-calcaneal complexes.     

腓骨短缩对胫距关节生物力学接触特性的影响

[目的]测定腓骨短缩时,胫距关节的接触特性的变化,探讨腓骨短缩的最大允许程度。[方法]6具小腿标本,去除踝关节以上的皮肤、肌肉等软组织,用夹具将其固定于正常行走踝关节中立位,分别测出在正常,腓骨短缩2、4、6 mm时,胫距关节的接触压及接触面积并进行比较,观察并总结出接触压及接触面积的变化趋势。[结果]通过模拟试验发现,腓骨短缩时,胫距关节总接触面积呈减小趋势,前外、后外象限的接触面积、接触压呈增大趋势,而前内,后内象限的接触面积、接触压均减小。[结论]2 mm以上(包含2 mm)的腓骨短缩,均会造成胫距关节接触特性的显著改变。     

Einfluss von Prozessierung und Sterilisation auf die Festigkeit von Pins aus boviner Tibiakompakta

In a biomechanical study pins made of xenogenous cortical bone were tested in vitro. Forty pins of 3 mm diameter and 60 mm length were made of eight different cattle tibiae and allocated to five different treatment groups. Freeze-dried pins served as control group. Pins of the second group were preserved in concentrated sodium chloride solution and defatted with acetone (Tuto-plast processing). Pins of groups three to five were treated with sodium chloride and acetone and afterwards sterilized by different means (ethylene oxide, autoclavation, or gamma radiation). All pins were subjected to a three-point-bending test and a shear test. We found that bending strength and shearing strength were most increased after sodium chloride and acetone treatment, whereas after sterilization with ethylene oxide or autoclaving, the stability of the pins was similar to the control group. The stability was considerably diminished after gamma radiation. Taking into account possible toxic side effects of ethylene oxide, we conclude that Tutoplast processing followed by autoclavation presents a reliable preparation method for the clinical use of implants made of bovine cortical bone.     

钛制弹性髓内钉微创治疗锁骨中段骨折的生物力学研究

[目的]探讨钛制弹性髓内钉微创治疗锁骨中段骨折内固定的生物力学性能,为临床应用提供科学依据。[方法]采集18具成人新鲜锁骨标本,制成中外1/3处锁骨骨折模型,分别采用钛制弹性髓内钉、重建钢板和克氏针内固定,运用实验应力分析方法测试其生物力学性能进行比较。[结果]钛制弹性髓内钉在强度、刚度和稳定性及应力遮挡方面比重建钢板、克氏针内固定来得优越,统计显示具有显著性差异(P<0.05)。[结论]钛制弹性髓内钉微创治疗锁骨中段骨折比传统的重建钢板和克氏针内固定具有一定的优势,生物力学性能优越,微创术式固定,操作方便,是目前锁骨骨折内固定的理想术式。     

磷酸钙骨水泥加固颈椎前路单皮质骨螺钉的生物力学研究

[目的]评价磷酸钙骨水泥（calcium phosphate cement，CPC）对颈椎前路单皮质骨螺钉固定的加固作用。[方法]单皮质骨螺钉固定于C3-6椎体标本，行轴向拔出实验，周期抗屈实验，抗剪切力测试。[结果]修复组、强化组螺钉的最大轴向拔出力（POS）明显高于对照组，强化组周期抗屈后位移明显小于对照组，而最大抗剪切力明显大于对照组。[结论]磷酸钙骨水泥能显著提高螺钉的最大轴向拔出力及抗剪切能力，对颈椎前路螺钉的固定有明显的加强作用。     

聚羟基丁酸酯可吸收缝线灭菌方法的实验研究

目的：研究不同的灭菌方法对聚羟基丁酸酯（PHB）可吸收缝线的降解性和力学特性的影响。方法：将聚羟基丁酸酯（PHB）可吸收缝线进行酒精浸泡、环氧乙烷、紫外线照射三种方法进行灭菌处理后,用细菌培养检测灭菌效果,用粘度法测定聚合物分子量从而观察缝线的降解性,用拉伸试验测定缝线的力学特性。结果：①酒精浸泡灭菌组有10%检出细菌,环氧乙烷及紫外线灭菌组未检出细菌;②紫外线照射灭菌和酒精浸泡灭菌组可使缝线黏度下降并具有显著性差异,环氧乙烷对缝线黏度下降的影响没有显著性差异;③经酒精和紫外线灭菌后缝线的断裂强度降低明显,差异具有显著性,经环氧乙烷灭菌后缝线的断裂强度降低无显著性差异。经紫外线灭菌后缝线的断裂伸长率明显降低,差异具有显著性,经酒精和环氧乙烷灭菌后缝线的断裂伸长率无明显降低。结论：环氧乙烷灭菌对PHB可吸收缝线的降解性和力学特性影响较小,是PHB可吸收缝线较理想的灭菌方法。