骨折周围骨痂移植治疗骨不愈合的形态学观察

目的 观察骨不愈合采用骨折断端周围自体骨痂移植治疗的效果。方法 新西兰兔42只,双侧桡骨中段模拟骨折,考察至明显骨痂生长随机分配实验I组36只,实验Ⅱ组6只,随机选择一侧髂骨切取部分全层骨和双侧骨折处周围骨痂备用,并建立1．0cm骨缺损的标准不愈合模型。实验Ⅰ组,左桡骨移植骨痂为A组,右桡骨移植髂骨为B组,术后分别为2、4、6、9、12、15周各处死6只兔并取标本作X线摄片和图像分析、标本大体观察,组织切片检查。实验组Ⅱ组,左桡骨移植髂骨为C组,右桡骨空白对照为D组,术后定期X线摄片检查。结果 ①术后15周,A、B、C组全部完成骨不愈合的修复;②D组无一例骨不愈合完整修复;③A、B组修复骨不愈合的病理过程相仿,首先是桥梁骨痂和连续骨痂形成,而后是成熟骨板期,最后是塑形期,但修复进程在实验9周存在明显差异（P＜0．05）,A组优B组。结论 骨折周围骨痂和髂骨都是较为理想的骨移植材料,在治疗骨不愈合过程中,骨痂移植在早期有加速骨缺损修复的趋势。     

骨折周围骨痂移植治疗骨不愈合的形态学观察

目的　观察骨不愈合采用骨折断端周围自体骨痂移植治疗的效果。方法　新西兰兔 42只 ,双侧桡骨中段模拟骨折 ,观察至明显骨痂生长随机分配实验Ⅰ组 36只 ,实验Ⅱ组 6只 ,随机选择一侧髂骨切取部分全层骨和双侧骨折处周围骨痂备用 ,并建立 1 0cm骨缺损的标准不愈合模型。实验Ⅰ组 ,左桡骨移植骨痂为A组 ,右桡骨移植髂骨为B组 ,术后分别于 2、 4、 6、9、 12、 15周各处死 6只兔并取标本作X线摄片和图像分析、标本大体观察 ,组织切片检查。实验Ⅱ组 ,左桡骨移植髂骨为C组 ,右桡骨空白对照为D组 ,术后定期X线摄片检查。结果　①术后 15周 ,A、B、C组全部完成骨不愈合的修复 ;②D组无一例骨不愈合完整修复 ;③A、B组修复骨不愈合的病理过程相仿 ,首先是桥梁骨痂和连接骨痂形成 ,而后是成熟骨板期 ,最后是塑形期 ,但修复进程在实验 9周存在明显差异 (P <0 0 5 ) ,A组优于B组。结论　骨折周围骨痂和髂骨都是较为理想的骨移植材料 ,在治疗骨不愈合过程中 ,骨痂移植在早期有加速骨缺损修复的趋势。     

皮质骨骨痂延长骨愈合的组织形态学观察

对皮质骨骨痂延长骨愈合过程的组织形态学变化进行观察。方法：在山羊左胫骨中段骨膜下横形截骨后用Ｉｌｉｚａｒｏｖ式外固定器固定。２周后作牵拉延长,每天１ｍｍ,连续３０天。定期摄Ｘ线片,并于截骨后１、２周,延长开始后１、２周,延长结束及结束后２、４、８、１２、１６周分期取材,作普通及偏光观察。结果：在骨痂延长早期,骨外膜侧即有直接骨形成,而延长间隙中先形成纤维组织,以后逐渐向纤维骨痂、骨性骨痂演变,最终形成新生皮质骨。结论：皮质骨骨干截骨后持续缓慢牵拉,对形成中的骨痂施以轴向的机械性张应力,能维持并刺激骨与软组织的再生,使截骨端间获得完全的骨愈合。其成骨方式可能以膜内骨化为主。     

前臂骨折愈合过程中骨痂骨密度的变化

目的：应用双有Ｘ线骨密度测定仪（ＤＥＸＡ）观察前臂骨折愈合过程中骨痂的骨密度变化,为临床提供一种测定骨折愈人事程度的方法。方法：对１７１例前臂骨折在正常愈合过程中骨折端区及其相邻两侧非骨折区骨矿物密度（ＢＭＤ）变化,将结果进行自身对照研究。结果：在观察期内,骨折区ＢＭＤ值呈显著上升趋势。非骨折区的ＢＭＤ则明显降低。结论：ＢＥＸＡ对骨折谪蝗ＢＭＤ跟踪测定可客观准确地反映骨折端骨痂生长状况,从而使骨折     

骨折周围骨痂移植治疗骨不愈合

目的观察用骨痂移植对骨折不愈合作用的临床疗效。方法1995年1月～2003年12月共收治增生型骨折不愈合19例,采用骨痂移植加内固定或外固定治疗。其中男16例,女3例;年龄19～57岁。骨折部位：肱骨4例,尺桡骨2例,股骨8例,胫骨5例。均为增生型骨折端有大量骨痂形成,其中普通钢板固定松动变形10例,加压钢板松动2例,梅花针固定变形3例,带锁髓内钉断裂2例,普通钢板断裂2例。骨折不愈合时间8～24个月。结果19例均获6～18个月随访,平均15.6个月。骨折愈合时间为6～8个月,其中1例术后7个月外伤后再骨折,钢板弯曲,经手术及骨痂骨植骨后7个月愈合。钢板内固定及交锁髓内钉治疗者无伤口感染;外固定架固定者1例针道感染,经消炎、换药痊愈。上肢骨折6例功能恢复良好;下肢骨折13例除上述1例再骨折功能恢复稍差外,其余功能恢复良好。结论采用骨痂移植简便易行,骨折愈合率高,可作为一种治疗骨不愈合的骨移植材料。     

异体软骨痂移植的初步结果

目的 通过观察异体软骨痂移植后的生物学过程判断其作为植骨材料的可行性。方法 将1只SD大鼠的双侧股骨干造成闭合骨折,1周时切开获取软骨痂,－196℃冻存2周后移植于5只SD大鼠的左侧胫骨干部分缺损区（此骨缺损模型的成骨活动只表现为膜内化骨的方式）,右侧植入异体松质骨作为对照组。将取材标本制成不脱钙切片,经亮绿和藏红T染色。结果 术后1周取材1例,缺损区实验侧和对照侧均未见有软骨组织和骨组织形成。术后2周处死其余4只大鼠,实验侧（3／4）可见有软骨组织和骨组织形成。骨组织内已有髓腔形成,骨组织周围是软骨组织,与宿主骨之间有纤维组织相隔。结论 异体软骨痂移植后未被吸收,可经软骨内化骨的方式产生骨组织,为软骨痂作为植骨材料的进一步研究和开发提供了初步依据。     

雄性激素减少对骨折愈合过程中骨痂显微结构变化的影响

目的探讨雄性激素减少对骨折愈合过程中骨痂显微结构变化的影响。方法清洁级SD大鼠40只,6月龄,随机分为骨折组（A组）及睾丸切除＋骨折组（B组）,建立骨折模型,造模后第3、7、14、21d,每组随机选取5只大鼠,切取骨痂标本,在显微镜下观察骨痂显微结构并拍片观察。结果A组毛细血管侵入时间、成纤维细胞、成软骨细胞、成骨细胞出现时间早于B组,且功能较B组活跃。结论睾丸切除后雄性激素下降对骨折愈合的影响,主要发生在骨折中后期,表现为软骨骨痂向骨性骨痂演变缓慢和骨改建期间骨吸收加剧。     

矩形髓内钉对实验性骨折愈合过程中骨痂含量的影响

目的：探讨矩形髓内钉（Rectangle -shaped Intramedullary,Nail,简称RIN）对骨折愈合过程中骨痂含量的影响。方法：用兔胫骨骨折内固定模型将RIN和传统的Ender's钉（Ender's Nalis，简称END）、四孔接骨板（Stainless Steel Plates，简称SPL）进行对比研究，通过阅片及计算机图像分析系统对不同内固定后不同时期的骨痂X线片进行分析。结果：骨痂直径测量显示：同组相比，8周时骨痂直径最大；同期比较，RIN组骨痂直径最大，END组次之，SPL组最少。RIN、END组和SPL组组间均有显著差异，RIN和END组相比则无显著差异；骨痂灰度密度分析显示：同组的骨痂灰度密度值随术后时间的增加而增大；同期比较，8周组的骨痂灰度密度值最高，END组次之，SPL组最少。RIN、END组和SPL组组间均有显著差异，RIN和END组相比，RIN组8周后组间差异显著。结论：RIN组和END组在骨折的不同时期的骨痂量较SPL组多，而且骨痂的钙化也较早，促进了骨折愈合。     

骨折愈合过程中骨痂骨密度的定量分析

目的：应用双能X线骨密度测定仪（DEXA）观察骨折愈合过程中骨痂听骨密度变化，说明临床测定骨折愈合程度的方法。方法：对171例前臂骨折在正常愈合过程中骨折端区有其相邻两侧非骨折区骨矿物密度（BMD）变化，将结果进行自身对照研究。结果：在整个观察期内，骨折区BMD值呈显著上升趋势（P＜0．01）。结论：DEXA对骨折端听BMD跟踪可测定可客观准确地反映骨折端骨痂生长状况，从而使骨折愈合检测数量化。     

Size and habit of mineral particles in bone and mineralized callus during bone healing in sheep

Bone healing is known to occur through the successive formation and resorption of various tissues with different structural and mechanical properties. To get a better insight into this sequence of events, we used environmental scanning electron microscopy (ESEM) together with scanning small‐angle X‐ray scattering (sSAXS) to reveal the size and orientation of bone mineral particles within the regenerating callus tissues at different healing stages (2, 3, 6, and 9 weeks). Sections of 200 µm were cut from embedded blocks of midshaft tibial samples in a sheep osteotomy model with an external fixator. Regions of interest on the medial side of the proximal fragment were chosen to be the periosteal callus, middle callus, intercortical callus, and cortex. Mean thickness (T parameter), degree of alignment (ρ parameter), and predominant orientation (ψ parameter) of mineral particles were deduced from resulting sSAXS patterns with a spatial resolution of 200 µm. 2D maps of T and ρ overlapping with ESEM images revealed that the callus formation occurred in two waves of bone formation, whereby a highly disordered mineralized tissue was deposited first, followed by a bony tissue with more lamellar appearance in the ESEM and where the mineral particles were more aligned, as revealed by sSAXS. As a consequence, degree of alignment and mineral particle size within the callus increased with healing time, whereas at any given moment there were structural gradients, for example, from periosteal toward the middle callus. © 2010 American Society for Bone and Mineral Research.     

Role of mechanical loading in the progressive ossification of a fracture callus

The progressive ossification pattern in a fracture callus was predicted based on a theory that relates the local stimulus for ossification to the tissue mechanical loading history. Two-dimensional finite element analyses of a fracture callus were considered at three different stages of ossification. The sites of callus ossification represented in the initial model were predicted by previous analyses relating mechanical stress and vascularity to the differentiation of mesenchymal tissue in the early callus. The zones of further ossification, bone bridging, and bone consolidation predicted in the present study were found to be similar to the ossification patterns that have been documented by other researchers. The approach used to predict fracture healing is identical to that of previous studies predicting joint morphogenesis, with the exception that fracture healing requires continuous, attached skeletal elements, whereas joint morphogenesis requires discontinuous, articulating skeletal elements.     

Biochemical characterization of fracture callus proteoglycans

The changes in proteoglycan molecules during the initial stages of fracture healing in rats were characterized. Following extraction of callus proteoglycan components with dissociative solvents, the components were purified in a cesium chloride density gradient. The recovered proteoglycans were characterized with respect to their molecular size distribution using gel filtration chromatography and a centrifugal transport methodology. During this early healing period, a decrease was observed in the relative proportion of the aggregate and in the hydrodynamic size and sedimentation coefficients of these molecules. While some molecular degradation could have occurred during the early stages of fracture healing, the dominant change of the proteoglycan molecules seemed to be disaggregation. No significant difference was observed in the proportion of aggregates reformed when exogenous hyaluronate and link glycoproteins were allowed to interact with the two corresponding monomer preparations. The molecular changes of the proteoglycan molecules seem to parallel those occurring during endochondral calcification of rat epiphyseal cartilage.     

Systemic leptin administration alters callus VEGF levels and enhances bone fracture healing in wildtype and ob/ob mice

IntroductionLeptinʼs role in bone formation has been reported, however, its mechanism of affecting bone metabolism is remaining unclear. In this study, we aimed to test whether leptin has a positive effect on fracture healing through the possible mechanism of increasing vascular endothelial growth factor (VEGF) expression in callus tissue.MethodsStandardized femur fractures were created in leptin-deficient ob/ob and wildtype C57BL/6J mice, and recombinant mouse leptin or its vehicle (physiological saline) was administered intraperitoneally during the study. Body weight, radiological, histologic and immunoblotting analyses were performed at different stages of fracture healing.Key findingsThe results showed that leptin treatment led to lower rate of body weight change in both mice genotypes. Radiological and histological analyses showed that the experimental groups had better fracture healing at 14, 21 and 28 days compared to the control groups. Leptin-treated groups had significantly higher VEGF expression in callus compared with the control groups at 2 and 3 weeks post-fracture except normal mice at 2 weeks, and leptin-deficient mice had higher VEGF levels in calluses than normal mice at the same timepoint.ConclusionLow-dose systemically-administered leptin has a positive effect on promoting fracture healing during the latter stages in a clinically-relevant mouse bone fracture model, and increase callus VEGF levels.     

The fracture gap size influences the local vascularization and tissue differentiation in callus healing

Background Revascularization of a fracture depends on fracture stability and fracture gap conditions. The aim of the study was to determine quantitatively the revascularization and tissue differentiation in an animal model with different fracture gaps and controlled biomechanical conditions.Materials and method The study was performed on ten sheep with an osteotomy on the right metatarsal. The fracture was stabilized by an external fixator that allowed adjustable axial interfragmentary movement. Two groups of five sheep each were adjusted to a medium sized gap (M, 2.1 mm) and a large gap (L, 5.7 mm) under comparable interfragmentary strain (30–32%). The animals were killed after 9 weeks, and the metatarsals were prepared for undecalcified histology and analysis of tissue differentiation and vessel distribution.Results Group M showed significantly more revascularization (M=1.62, L=0.85 vessels/mm²), more bone formation (M=37.2%, L=13.9%) and less fibrocartilage tissue (M=18.1%, L=39.1%) than group L. Larger vessels (>40 m) were found mainly in the medullary channel, and smaller vessels (<20 m) mainly in the peripheral callus. Histologically, group M showed partial bony bridging of the osteotomy gap, and the group L had delayed healing.Conclusion A good reduction of a fracture with small interfragmentary gaps is important for its revascularization and healing.     

Odanacatib increases mineralized callus during fracture healing in a rabbit ulnar osteotomy model

The effects of the cathepsin K inhibitor odanacatib (ODN) on fracture healing were monitored for ～6 and 15 weeks post‐fracture in two separate studies using the unilateral transverse mid‐ulnar osteotomy model in skeletally mature female rabbits. Rabbits were pre‐treated for 3–4 weeks with vehicle (Veh), ODN (2 mg/kg, po, daily), or alendronate (ALN) (0.3 mg/kg, sc, twice‐weekly) prior to osteotomy. In Study 1, the animals were maintained on the same respective treatment for ～6 weeks. In Study 2, the animals were also continued on the same therapy or switched from Veh to ODN or ODN to Veh for 15 weeks. No treatment‐related impairment of fracture union was seen by qualitative histological assessments in the first study. Cartilage retention was detected in the calluses of ALN‐treated rabbits at week‐6, while calluses in the ODN and Veh groups contained bony tissue with significantly less residual cartilage. ODN treatment also markedly increased the number of cathepsin K‐(+) osteoclasts in the callus, indicating enhanced callus remodeling. From the second study, ex vivo DXA and pQCT confirmed that ODN treatment pre‐ and post‐osteotomy increased callus bone mineral content and bone mineral density (BMD) versus Veh (p < 0.001) and discontinuation of ODN post‐surgery returned callus BMD to Veh. Peak load of ODN‐ or ALN‐treated calluses were comparable to Veh. ODN increased callus yield load (20%, p = 0.056) and stiffness (26%, p < 0.05) versus Veh. These studies demonstrated that ODN increased mineralized callus during the early phase of fracture repair without impairing callus formation or biomechanical integrity at the fracture site. © 2015 The Authors. Journal of Orthopaedic Research published by Wiley Periodicals, Inc. on behalf of the Orthopaedic Research Society. J Orthop Res 34:72–80, 2016.     

The effect of a brain lesion on bone healing

Using a feline model, the effects of stereotaxic brain lesions producing unilateral spasticity on bilateral fibular osteotomies were observed. Healing in spastic limbs occurred with more new bone formation than on the contralateral (control) side. Union appeared to be slightly faster in spastic limbs. Histomorphometric analysis of resected fibular specimens following union revealed little difference between spastic and non-spastic limbs. When these brain-lesioned animals were compared with a group with identical osteotomies but no brain lesions in respect of various systemic biochemical and endocrine parameters, no differences were found.     

高能量骨折延期手术促进骨愈合的实验研究

目的研究延期手术刺激旺盛的外骨痂生长在高能量骨折中的作用,探索提升骨折愈合能力的新途径。方法取成年狗20只,随机分为ABCD四组,各组均行股骨中段线锯截骨,电凝破坏周围骨膜,制造1 cm缺损,8孔钢板固定。A组截骨14 d后行内固定,B组即时内固定,C组即时内固定,但不用电凝破坏骨膜,D组14 d后行内固定,但固定时切除骨端周围已形成的肉芽。结果狗股骨破坏骨膜制造骨缺损后,早期手术固定组无外骨痂生长,几乎无内骨痂生长,引发了萎缩性骨不连;在同样破坏骨膜制造骨缺损的情况下延期手术固定组产生了旺盛的骨痂生长,产生了稳定固定下的骨痂愈合。结论高能量骨折早期手术固定抑制外骨痂生长,容易造成骨痂生长不良的低质量愈合现象。延期手术固定可以刺激良好的外骨痂生长,改善骨折愈合能力,预防骨不连的发生。     

Temporal delimitation of the healing phases via monitoring of fracture callus stiffness in rats

The healing process consists of at least three phases: inflammatory, repair, and remodeling phase. Because callus stiffness correlates with the healing phases, it is suitable for evaluating the fracture healing process. Our aim was to develop a method which allows determination of callus stiffness in vivo, the healing time and the duration of the repair phase. The right femurs of 16 Wistar rats were osteotomized and stabilized with either more rigid or more flexible external fixation. Fixator deformation was measured using strain gauges during gait analysis. The strains were recalculated as the callus stiffness over the time course of healing, and the healing phases were identified based on stiffness thresholds. Our hypothesis was that stabilization with more flexible external fixation prolongs the repair phase, therefore resulting in an extended healing time. Confirming our hypothesis, the duration of the repair phase (rigid: approximately 15 days, flexible: approximately 41 days) and the healing time (rigid: approximately 27 days, flexible: approximately 62 days) were significantly longer for more flexible external fixation. Our method allows the quantitative detection of differences in the healing time and duration of the repair phase without multiple time‐point sacrifices, which reduces the number of animals in experimental studies. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:1589–1595, 2014.