可控性应力与微动对骨折愈合影响的组织学研究

目的 探讨骨折端在不同轴向应力作用下,不同骨折愈合时期所需轴向应力的适宜力值. 方法 32只青山羊均行股骨干中段横行截骨制作骨折模型,按骨折端施加实验动物自身体质量的0倍(对照组)、1/6(A组)、1/3(B组)、1/2(C组)应力分为4组,每组8只.术后4、8周分批处死,每次每组处死4只,行大体观察和组织学观察,测量骨折端骨外膜骨痂面积. 结果 对照组有1只动物骨折端发生成角畸形,实验A、B、C组分别有1、2、4只动物骨折端发生成角畸形.术后4周,对照组、A、B、C组骨折端骨外膜骨痂面积平均值分别为(1.15±0.34)、(1.86±0.28)、(2.18±0.36)、(1.99±0.33)cm~2,A、B、C组分别与对照组比较,骨折端骨痂生成多,骨外膜骨痂面积差异有统计学意义(P<0.05).术后8周,沿轴向排列骨外膜骨痂中骨性骨痂多、致密,皮质骨松化明显;对照组、A、B、C组骨折端骨外膜骨痂面积平均值分别为(1.38±0.31)、(2.09±0.23)、(2.69±0.28)、(2.71±0.31)cm~2,A、B、C组分别与对照组比较,B、C组分别与A组比较,差异均有统计学意义(P<0.05). 结论 骨折端施加轴向应力时能促进骨折端骨痂生长,较大的应力强度能更好地促进骨折端骨痂生长,但同时会造成骨折愈合成角畸形发生率增高.骨折端施加自身体质量的1/3应力时骨折端成角畸形发生率较低,最适宜促进骨折端骨痂生长.     

高压氧对小鼠胫骨骨折愈合过程中骨生物力学特性及胶原蛋白含量的影响

目的 探讨高压氧对小鼠胫骨骨折愈合过程中骨生物力学特性及胶原蛋白含量的影响.方法 采用简单随机抽样法将216 只昆明小鼠随机分为对照组（108 只）和高压氧组（108 只）,建立胫骨骨折模型.高压氧组予以高压氧治疗,对照组不予高压氧治疗.分别于骨折后1、2、3、4 周取材,取材前通过行为学评分和斜板实验评价两组小鼠的行为学特征,观察取材后胫骨的一般生物学特征,检测胫骨标本的抗扭力和抗折力,测定胫骨骨痂组织的胶原蛋白含量,同时采用改良Masson 染色对骨痂组织中的胶原蛋白进行组织学观察.结果 与对照组相比,高压氧组小鼠骨折后1、2 周行为学评分降低;2、3、4 周斜板实验坡度升高（P ＜0.05）.骨折后1周高压氧组小鼠右侧胫骨宽度（骨痂处）、胫骨抗折力均大于对照组,两组比较,差异有统计学意义（P ＜0.05）;骨折后2 周高压氧组小鼠右侧胫骨抗扭力高于对照组,骨折后1、2、3 周右侧与左侧胫骨抗扭力比值以及两侧胫骨抗折力比值均高于对照组,两组比较,差异有统计学意义（P ＜0.05）;高压氧组小鼠骨折后1、2、3、4 周骨痂胶原纤维含量高于对照组（P ＜0.05）,且高压氧组改良Masson染色出现较多的蓝色反应.结论 在小鼠胫骨骨折的愈合过程中,高压氧治疗提高了骨痂组织中胶原蛋白的含量,增强了骨的生物力学性能,对骨折愈合起到促进作用.     

人工合成成骨生长肽促进兔胫骨骨折愈合的实验研究

目的观察人工合成的成骨生长肽(sOGP)经静脉应用对兔胫骨骨折愈合的影响。方法52只新西兰大白兔制成胫骨中段截骨、髓内钉固定骨折模型后,随机分为两组。实验组从术后第1d开始每天注射sOGP0.5μg·kg-1至取材前1d,对照组注射同样剂量的生理盐水。分别于术后第1、2、3、4、6周每组宰杀3～5只,测定血清ALP、BGP;同时取材测定骨折端骨密度、摄X线片后,再行组织学检查和形态分析,观察骨痂的大小及其组成成分的变化;其中术后6周的标本还进行了生物力学测定。结果实验组血清ALP、BGP水平高于对照组。X线片显示两组骨折均愈合,第3、4周实验组外骨痂平均面积比对照组大,3周时为265.44mm2、209.95mm2,4周时为233.10mm2、209.21mm2。第3、4、6周的骨密度实验组均大于对照组,其中第4周的骨密度经F检验两组的差异具有显著性(P<0.05)。组织学形态分析显示第2、3、4周的外骨痂平均面积实验组比对照组大;所有实验组外骨痂中小梁骨占骨痂总面积的百分比均高于对照组,其中第2、4周经F检验两组的差异具有显著性(P<0.05)。第6周骨折端平均最大破坏载荷及最大位移实验组比对照组高,但差异没有显著性(P>0.05)。结论全身应用sOGP对不稳定固定的兔胫骨横断骨折的愈合具有一定的促进作用。     

低频可控性微动影响长骨骨折愈合的实验研究

目的应用可控性微动外固定支架研究骨折端低频微动对骨痂增殖和骨折愈合的影响。方法绵羊39只,双侧胫骨中段横行截骨,间隙2mm,用连有微动装置的单边外固定支架固定。术后10d,随机选择一侧肢体进行微动,按不同的微动频率分为3组:A组0.5Hz,B组1Hz,C组5Hz;幅度为0.25mm,4周结束(30min/d)。另一侧肢体不微动,为对照组。分别于术后4、6、9周切取标本进行大体观察、X线检查、组织学检测及生物力学测试。结果大体与X线检查显示各实验组均有大量的骨痂生成,4周末达高峰;组织学检测显示微动组骨痂软骨内骨化与类骨质形成的速率在6周最为明显,均快于对照组,以B组形成速率最快。9周末生物力学测试微动组弯曲刚度均强于对照组,以B组的力学强度最大。结论骨折端低频微动在骨折愈合早期均能有效地促进骨痂生长,加速骨痂的矿化,以1Hz频率效果最佳。     

胫骨延长后骨痂直径与新生骨预后关系的临床分析

目的探讨胫骨延长后骨痂直径与新生骨预后的关系.方法 1996年1月～2001年12月,对68例胫骨延长者测量达所需延长长度时的骨痂直径,计算骨痂直径率(callus diameter ratios,CDR);统计拆除外固定架后2～4周时新生骨发生骨折例数及畸形角度,比较骨折和成角畸形与CDR的关系.结果拆除外固定架前胫骨前屈角度5度以上畸形19例,其中11例发生骨折;拆除外固定架后胫骨出现5度以上畸形6例,其中2例骨折;其余43例胫骨延长骨痂正常愈合.计算CDR值:CDR值小于80% 23例,其中发生新生骨骨折13例,成角畸形5度以上者21例;CDR在81%～85%之间6例,成角畸形5度以上4例;CDR值超过86% 39例,无畸形或新生骨骨折.结论胫骨延长时CDR小于80%时,容易发生新生骨骨折和畸形;CDR大于85%时,无新生骨骨折和畸形发生;两组间具有统计学意义(P＜0.05).CDR是判断骨痂能否正常愈合较为理想的检测指标.     

不同神经损伤对骨折前期愈合影响的实验研究

目的：研究脊髓和周围神经损伤对骨折前期修复的影响。方法：将实验大鼠分成3组，一组为T10脊髓横断伴股骨骨折，另两组分别为周围神经切断伴股骨骨折组和单纯股骨骨折组。骨折后2周和4周摄股骨X线片，4周处死大鼠行骨痂细胞和组织学检查。结果：骨折后2周3组均未出现明显骨痂，术后4周测量x线片骨痂大小显示周围神经切断组骨痂最多，其次分别为对照组和脊髓损伤组。组织学显示周围神经切断组骨痂量多，并有明显的皮质骨桥接断端，但其中类骨质较多，骨钙的沉积相对较少，而且骨痂缺乏血管和正常的骨小梁结构，骨化重建不够理想；而脊髓损伤组骨痂则表现为欠成熟，细胞种类多，分布紊乱，少部分仍处于纤维修复阶段。对照组的组织学改变介于两者之间，但其骨小梁结构良好而且骨钙沉着明显。结论：不同类型神经损伤对骨折愈合前期有着不同的影响。失周围神经支配对骨折修复有一定的加速作用，而脊髓损伤则延缓了骨折前期愈合，其发生机理仍需进一步研究。     

骨折合并颅脑损伤大鼠血小板衍生生长因子表达的研究北大核心CSCD

目的观察胫骨骨折合并颅脑损伤大鼠血清及骨痂组织内血小板衍生生长因子（PDGF）的表达变化,探讨颅脑损伤对骨折愈合的影响及作用机制。方法选择144只SD大鼠随机分为4组（n=36只）：正常对照组（N组）、颅脑损伤组（TBI组）、单纯骨折组（F组）和骨折合并颅脑损伤组（TBI＋F组）,并制作相应组别的损伤模型。造模后第3天、1周、2周、3周、4周处死大鼠,4组均采用酶联免疫吸附试验法检测大鼠血清PDGF的表达;F组和TBI＋F组大鼠通过x线片观察右胫骨骨折处骨痂生长情况,通过苏木精．伊红染色观察骨痂生长及组织形态,免疫组织化学法检测骨痂组织PDGF的表达,逆转录聚合酶链反应法检测骨痂组织PDGFmRNA的水平,并进行比较。结果x线片示TBI＋F组大鼠骨折愈合速度比F组快。TBI＋F组大鼠血清PDGF表达量较其他3组高,且峰值时间提前,差异均有统计学意义（P〈0．05）。TBI＋F组大鼠骨折端局部成骨活动较F组强。TBI＋F组大鼠第3天、1周时局部骨痂组织中PDGF阳性细胞数较F组明显增多升高,且峰值时间提前,差异均有统计学意义（P〈0．05）。TBI＋F组大鼠第3天、1周时局部骨痂组织中PDGFmRNA表达水平较F组显著增高,差异均有统计学意义（P〈0．05）。结论颅脑损伤可以加速大鼠骨折愈合的进程,这可能与颅脑损伤后大鼠体内PDGF的表达增高有关。     

神经生长因子对胫骨骨折大鼠骨力学、骨强度及骨桥蛋白及下游相关因子水平的影响

目的 探讨神经生长因子（NGF）对胫骨骨折大鼠骨力学、骨强度及骨桥蛋白（OPN）及下游相关因子水平的影响。方法 将42只大鼠按照随机数字表法分为A组（腓肠肌两侧注射生理盐水）、B组（腓肠肌两侧注射NGF）,每组21只。建立胫骨骨折模型后,观察两组骨痂的大小、骨折愈合情况,测定生物力学检测指标（最大载荷、弹性载荷、最大挠度）、胫骨骨强度指标（骨密度和骨矿含量）,HE染色观察胫骨骨折形态,Western blot法检测OPN和局部黏着斑激酶（FAK）蛋白表达。结果 (1) B组骨折愈合更快,更早地完成了骨痂重塑,且愈合过程中,形成的骨痂更大。(2)术后1、3、5周,B组最大载荷、弹性载荷、最大挠度及OPN、FAK蛋白表达、骨密度明显大于A组（P<0.05）,骨矿含量明显少于A组（P<0.05）;A组术后各时间点各项指标比较差异均无统计学意义（P> 0.05）;B组骨矿含量随时间推移逐步降低,其余指标随时间推移逐步升高（P<0.05）。(3) B组骨痂组织中软骨组织形成更早,面积更大,软骨组织向骨组织转化的过程更快。结论 NGF可以改善大鼠胫骨骨折最大载荷、弹性载荷、...     

黄骨髓对兔骨折愈合影响的实验研究

[目的]研究自体黄骨髓一期移植对骨折愈合作用的实验疗效,观察黄骨髓是否具有成骨能力,为进一步临床应用提供理论依据。[方法]36只新西兰大白兔随机分为3组,建立左侧胫骨骨折延迟愈合模型,A组仅以钢板内固定;B组钢板内固定后,植入空白明胶海绵,C组钢板内固定后,植入黄骨髓与明胶海绵复合物。术后每组分别于2、4、8、12周各处死3只动物,进行影像学检测、大体观察及HE染色检查,观察骨折愈合情况及骨痂形成情况。[结果]A组及B组在术后4周只可见少量骨痂形成,而C组在术后2周即可见骨痂形成,术后4周可见大量骨痂形成,至术后8周C组骨折线消失,而A、B组骨折线仍可见;术后12周,A、B组仍可见骨折线存在。[结论]黄骨髓在骨折后能明显促进骨折愈合,在预防骨不连或骨折延迟愈合中具有重要作用。     

血管内皮生长因子对骨折愈合相关因子表达的调控

目的探讨应用和拮抗血管内皮生长因子(VEGF）对骨折愈骨相关因子表达的影响，并观察骨折愈台过程中的病理改变。方法用105只天上I=白兔制作骨折模型．随机分为对照组、应用VECF组和拮抗vEGF组，分别于伤后8、24、72b和1．3、5、8周测定各组动物骨折端相关因子的表达变化、同时取骨折端标本脱钙进行兜镜观察。结果应甩VEGF使骨折端埘BMP的表达时同提前和延良，拈抗VEGF抑制rBMP的表达，应用VEGF组伤后3J嗣时骨折端充填有纤维性骨痴，软骨骨痂和骨性骨痂．5周时新生骨以编织骨为主，8周时骨折正常愈合；括抗VH押导受伤后初期骨细胞坏死增多，1～5周各时相点骨折端均有灶性坏死出现，3同时骨折部位血管生成明显减少。结论骨折愈台过程需要多因子参与、协调，VEGF有可能是作为骨折愈台过程中的一种重要因子在发挥作用     

Gene therapy with human osteoprotegerin decreases callus remodeling with limited effects on biomechanical properties

Osteoprotegerin (OPG) is a naturally occurring protein, which prevents bone resorption by inhibition of osteoclastogenesis, function, and survival. Therefore, recombinant OPG may be an attractive drug in the treatment of chronic bone resorptive diseases such as osteoporosis. Gene therapy has the potential to achieve long-term treatment by delivering genes of anti-resorptive proteins to the recipient. The effects of OPG gene therapy on fracture healing have not been described previously.

The influence of OPG gene therapy on callus formation, callus tissue structural strength, apparent material properties, and histology of tibia fractures in rats was investigated after 3 weeks and 8 weeks of healing. Intramuscular administration of adeno-associated virus (AAV) vector-mediated OPG resulted in increased levels of OPG in serum of approximately 100 ng/ml throughout the study period. Control animals with fractures received transduction with an AAV reporter gene construct (AAV-enhanced green fluorescent protein (eGFP)), and in this group serum OPG levels remained at baseline (<10 ng/ml). After 3 weeks of healing, AAV-OPG treatment reduced the number of osteoclasts in the callus tissue (33%, P < 0.001). However, AAV-OPG treatment did not influence callus dimensions, callus bone mineral content (BMC), fracture structural strength, or apparent callus tissue material properties. After 8 weeks of healing, AAV-OPG treatment reduced the number of osteoclasts in the callus tissue (31%, P < 0.001) compared with AAV-eGFP fractures. Furthermore, deposition of new woven bone at the fracture line of the original cortical bone was hampered (new woven bone present: in all AAV-eGFP animals, in 41% of AAV-OPG-treated animals, P < 0.001). AAV-OPG treatment also increased callus BMC (18%, P = 0.023) compared with AAV-eGFP fractures. AAV-OPG did not influence callus dimensions, structural strength of the fractures, or ultimate stress, whereas elastic modulus was reduced in the AAV-OPG groups (37%, P = 0.039). The experiment demonstrates that AAV-OPG gene therapy decreases the fracture remodeling, but this does not influence the structural strength of healing fractures.     

辛伐他汀对桡骨远端骨折老年女性骨密度及骨折愈合的影响

目的探讨辛伐他汀对老年女性桡骨远端骨折骨密度及骨折愈合的影响。方法分析98名桡骨远端骨折老年女性术前及术后3个月健侧桡骨远端1/3处骨密度,依据术后是否口服辛伐他汀治疗其他内科疾患分为辛伐他汀治疗组(56例)及对照组(42例)。结果治疗前辛伐他汀组与对照组健侧桡骨远端1/3处骨密度差异无统计学意义(P0.05)。治疗3个月后辛伐他汀组健侧桡骨远端1/3处骨密度与治疗前骨密度相比差异具有统计学意义(P0.05);对照组健侧桡骨远端1/3处骨密度均值增高,与初始时差异无统计学意义(P0.05)。治疗3个月后辛伐他汀组与对照组两组间骨密度差异无统计学意义(P0.05)。通过卡方检验分析发现辛伐他汀组与对照组相比骨折愈合数存在统计学差异,辛伐他汀可以促进骨折愈合;分析两组间治疗前后骨质正常、骨量减少、骨质疏松数之间差异无统计学意义,辛伐他汀不影响骨质疏松患病率。结论桡骨远端骨折老年女性应用辛伐他汀(20 mg/d)可以改善桡骨远端骨密度、促进骨折愈合,但不影响骨质疏松患病率。     

轴向载荷分担比指导外固定器动力化的临床应用

目的:探讨轴向载荷分担比用于胫腓骨骨干骨折术后指导外固定器轴向动力化促进骨折愈合的有效性。方法:选取外固定器治疗的胫腓骨骨干骨折患者100例,随机分为观察组50例,对照组50例。观察组在轴向载荷分担比指导下行外固定器轴向动力化治疗,对照组未行动力化,随访比较两组的治疗效果。结果:所有患者均获随访,随访时间4～12个月,平均6.5个月,治疗期间所有患者均未出现外固定针断裂、松动及再骨折等并发症,观察组1例骨搬移患者轴向载荷分担比5%,X线片显示骨折断端有连续性骨痂通过,拆除外固定器连接杆后发生移位,恢复原数值行轴向加压再动力化,现已愈合。观察组除外1例骨搬移患者,其余49例患者外固定器固定时间为[(24.4±4.7)周],骨折临床愈合时间为[(22.4±4.7)周],与对照组50例患者外固定器固定时间[(29.3±5.6)周],骨折临床愈合时间[(27.3±5.6)周]比较,显著减少(P0.05)。结论:外固定器轴向载荷分担比指导胫腓骨骨干骨折外固定术后轴向动力化可以加速骨折愈合,但不适合骨搬移截骨端已硬化患者。     

苯妥英促进骨折愈合的临床观察

目的　观察苯妥英对骨折愈合的促进作用。方法　选择40 例胫腓骨闭合性骨折患者,随机分为两组,治疗组用苯妥英和接骨丹口服,对照组仅用接骨丹口服。术后分期观察一般情况,纵向叩击痛,骨折临床愈合时间,X线片骨痂生长情况。结果　全部患者骨折均在伤后3个月内愈合,但治疗组纵向叩击痛、临床愈合时间及X线片骨痂生长均明显优于对照组。结论　口服苯妥英有明显的促进骨折愈合的作用。由于中成药接骨丹含有钙成分,避免了单用苯妥英使血钙降低的可能性     

Influence of extensive muscle injury on fracture healing in rat tibia

OBJECTIVES: The treatment of tibial fractures associated with severe soft tissue injury remains a challenge. The objective of our experiment was to ascertain the influence of standardized muscle injuries on fracture healing in a nailed rat tibial fracture model. We hypothesized that a severe crush injury of leg muscles might not be as deleterious to fracture healing as total loss of a large muscle segment. STUDY DESIGN: A randomized study in male Wistar rats with a diaphyseal osteotomy. METHODS: Three separate, but complementary experiments were done in 51 rats. The first experiment involved 30 rats randomly assigned to three increasingly severe soft tissue interventions in a nailed tibial osteotomy model. The second experiment involved 14 rats divided into two groups to study blood flow measurements of the muscle envelope after soft tissue injury. Seven rats were used in the third experiment to provide biomechanical data and dimensions of the rat tibia. The protocol for the first experiment was intramedullary nailing after a middiaphyseal osteotomy of the left tibia. In group A, the soft tissue injury was minimal, while the muscles in the anterolateral compartment were crushed in group B. Resection of the anterolateral compartment muscles, resulting in only skin coverage at the fracture site, was performed in group C. The fibular nerve was resected in all three groups so that the animals were non-weight bearing on the operated extremity. At 4 weeks, the healing bones in each group were studied clinically, radiographically, and biomechanically. RESULTS: Radiographs in two planes revealed a clearly visible fracture line in the three intervention groups at 4 weeks. The callus area following muscle resection in group C was significantly reduced compared with the minimal soft tissue injury in group A. Biomechanically, resection of the anterolateral compartment muscles in group C reduced maximum bending load and fracture energy compared with fractures with minimal soft tissue injury in group A, while bending rigidity and fracture energy was reduced compared with muscle crush in group B. No difference in mechanical characteristics was detected between the healing bones in groups A and B. CONCLUSION: This animal study indicates that crushing of the leg muscle envelope with reduced blood flow does not influence the quality of bone healing at 4 weeks to a significant degree. Resection of a large muscle segment impairs tibial fracture healing significantly.     

Osteoprotegerin Treatment Impairs Remodeling and Apparent Material Properties of Callus Tissue without Influencing Structural Fracture Strength

The influence of osteoprotegerin (OPG) treatment on callus formation, callus tissue structural strength, apparent material properties, and histology of tibia fractures in rats was investigated after 3 weeks and 8 weeks of healing. OPG was given intravenously (10 mg/kg twice weekly) during the entire observation period, and control animals with fractures received vehicle only. When compared with control fractures after 3 weeks of healing, OPG treatment reduced the number of osteoclasts in the callus tissue (93%, P < 0.001) and hampered resorption of genuine cortical bone in the fracture line; OPG treatment did not influence callus dimensions, callus bone mineral content (BMC), fracture structural strength, or callus tissue apparent material properties. When compared with control fractures after 8 weeks of healing; OPG treatment reduced the number of osteoclasts in callus tissue (92%, P < 0.001), augmented callus dimensions (anteriorposterior diameter: 12%, P = 0.034, mediolateral diameter: 13%, P = 0.013), and increased callus BMC (50%, P = 0.007); OPG treatment hampered deposition of new woven bone at the fracture line of the genuine cortical bone (new woven bone present in all vehicle animals, but only in 13% of the OPG-treated animals (P < 0.001)); OPG treatment did not influence structural strength of the fractures, but decreased apparent material properties of the callus tissue (ultimate stress: 51%, P < 0.001; elastic modulus: 42%, P = 0.033). The experiment demonstrates that OPG treatment does not influence the early callus expansion and fracture strength. However, during the subsequent period of remodelling, OPG treatment impairs the normal remodeling and consolidation processes.     

唑来膦酸治疗老年女性骨质疏松性骨折的研究

目的 研究唑来膦酸治疗老年女性骨质疏松性骨折的疗效。方法 选择2009年至2010年住院的60岁以上女性长骨骨折患者192例检测BMD,分为治疗组和对照组,两组均在治疗骨折同时给予钙剂和骨化三醇治疗,治疗组于术后1-2周给予唑来膦酸5mg静脉滴注。术后每12个月复查并记录腰椎部骨密度变化,同时观察术后骨折愈合情况、3年内再骨折率的差异。结果 在治疗三年后治疗组骨密度较对照组均有所提高,且差异有统计学意义（p<0.05）;术后三年内治疗组再骨折率低于对照组,且差异有统计学意义（p<0.05）;在骨折愈合方面两组随访3月骨折均愈合良好,结果差异无统计学意义（p>0.05）。结论 唑来膦酸可以有效降低老年女性骨质疏松性骨折患者的再骨折率、提高骨密度,且并不影响骨折愈合。     

Immunosuppression with FK506 has no influence on fracture healing in the rat

Immunosuppressant drugs like cyclosporine A and FK506 are widely used for solid organ transplantation. They are accelerating bone remodeling but cause net bone loss. The aim of this study was to investigate the effect of FK506 on fracture healing in the rat. Eighty Lewis rats were divided into four groups, which received FK506 (1 mg/kg BW) or no treatment for 2 or 4 weeks, beginning after production of a closed, nondisplaced unilateral tibial fracture. Radiographic, histological, and biomechanical studies were used to evaluate fracture healing and histomorphometric analysis of the tibial metaphysis of the intact contralateral side was performed. Radiographs revealed no difference of the healing of the control fractures compared with the fractures in the FK506-treated group at 2 and 4 weeks. The mechanical parameters of the tested contralateral intact tibiae and of the fracture callus demonstrated no difference between control and immunosuppressed animals. Tibial bone histomorphometry revealed increased measures of bone formation and bone resorption, accompanied by a significant reduction of percent trabecular area. At 4 weeks, the fractures showed osseous healing with woven bone at the fracture site and only minimal amounts of cartilage. Histological grading was not different between the control and the FK506 group at both time points. We conclude that systemic application of FK506 has no biomechanical and histological effects of experimental fracture healing in the rat. However, resorption far in excess of formation leads to a net bone loss in the trabecular bone of the tibia that has no effect on the stability of the intact bone.     

Interface contact profiles of a novel locking plate and its effect on fracture healing in goat

Objective： To evaluate the interface characteristics of the new-designed locking plate （LP） and limited contact-dynamic compression plate （LC-DCP） and compare the fracture healing between LP and LC-DCP in a goat tibia fracture model.
Methods： Eight-hole LP and LC-DCP were applied to fix fresh goat tibiae in a reproducible manner. The average pressure, force and interface contact area were calculated using Fuji prescale pressure sensitive film interposed among the plate and the bone and image analysis system, Eighthole LP and LC-DCP were applied to each tibia in a goat tibia fracture model. The fracture healing was evaluated by X-ray photography at postoperative 8 weeks. The goats were sacrificed at postoperative 12 weeks. Three-point bending test was conducted in the tibiae.
Results： The interface contact of LP system was smaller than that ofLC-DCP （P〈0.05）, while interface contact force of LP system was higher than that of LC-DCP （P〈0.05）. Radiographs revealed that the fracture line disappeared in the LP group, while the fracture line was visible in DCP group at postoperative 8 weeks. At postoperative 12 weeks, the bending strength and bending load of fractured tibia were higher in LP group than in DCP group, respectively.     

可吸收棒加骨水泥髓内固定的实验性研究

目的 研究自增强型可吸收棒（PDLLA）联合磷酸钙骨水泥（CPC）髓内固定管状骨骨折的可行性，为用于手部掌、指骨骨折提供实验室依据。方法 将自增强型可吸收棒植入兔股骨干（横形骨折）髓腔内，两端用磷酸钙骨水泥粘合固定（实验组），克氏针髓内固定（对照组）。术后比较两组周围组织的反应，X线片变化及力学强度。结果 术后4周实验组和对照组的股骨干横向截骨均未见明显畸形，X线片示实验组的骨痂量多于对照组；测定股骨三点弯曲最大破坏载荷实验，结果两组无明显差异。术后8周剪切力较术后4周无下降。术后8周两组的骨折均愈合，未出现局部反应性肿胀、积液、感染及全身毒性反应。结论 自增强型可吸收棒与磷酸钙骨水泥在骨内具有良好的组织相容性，两者联合应用行管状骨骨折髓内固定，效能与克氏针固定相当。