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。     

海水浸泡开放性骨折不同救治方法的实验研究

目的观察两种骨折固定方法救治海水浸泡开放性骨折的大体形态、组织病理学、影像学变化。方法取成年新西兰兔50只，随机分为三组：对照组10只、A组20只、B组20只。于胫骨中段截骨制成开放性骨折动物模型。对照组伤口自然旷置3h，A组和B组海水浸泡伤口3h。随后对照组和A组行伤口清创、钢板螺钉内固定术；B组行伤口清创、外固定架固定、伤口开放换药、二期缝合。观察各组的伤口感染情况、骨折愈合的组织学、影像学变化和测定骨折断端骨痂的平均比灰度值。结果a）对照组感染1只（10％），A组感染15只（75％），B组感染5只（25％）。各组间结果有统计学差异（P〈0．05）。b）术岳45d时各组间骨折断端组织愈合等级有统计学差异（P〈0．05）。c）术后45d时各组间骨折部位骨痂的生长情况在影像学上表现为对照组大于B组大于A组。各组间骨愈合率对照组为100％，A组为66．7％，B组为93．3％。d）术后45d时骨折断端间骨痂的平均比灰度值对照组为8．1149±1．2043，A组为6．2268±1．4000，B组为6．5138±1．3045，各组间有统计学差异（P〈0．05）。结论海水浸泡使开放性骨折伤口感染率增高；海水浸泡使开放性骨折断端骨痂形成不良率增高；骨外固定架与钢板内固定比较救治成功率提高。     

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、...     

自制植骨器在交锁髓内钉固定胫骨骨折中的应用

目的观察自制植骨器微创植骨在交锁髓内钉固定胫骨骨折中的临床应用疗效。方法对2009年5月至2011年12月收治的105例胫骨干骨折患者随机分成A、B两组,A组采用闭合复位交锁髓内钉固定,并于胫骨平台髓内钉入口处取骨,通过自制植骨器微创植骨;B组单纯采用闭合复位交锁髓内钉固定。两组在骨痂出现时间、骨折愈合时间、骨折愈合率、并发症发生率及胫骨平台稳定性等方面进行对比性研究。结果105例均获随访,随访时间1—3年,A组骨痂出现时间平均（28±3）d,骨折愈合时间平均（120±12）d,骨折愈合率98．1％,并发症发生率1．9％;B组骨痂出现时间平均（45±4）d,骨折愈合时间平均（155±13）d,骨折愈合率90．4％,并发症发生率9．6％。A、B两组在骨痂出现时间、骨折愈合时间及并发症发生率方面差异有统计学意义（P〈0．05）;在骨折愈合率方面A组优于B组,但差异无统计学意义（P〉0．05）。结论在闭合复位交锁髓内钉固定胫骨骨折的手术中,采用自制植骨器微创植骨可以使骨痂提早出现、缩短骨折愈合时间、减少并发症的发生率。     

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。     

股骨隐蔽性高能量骨折骨痂形成障碍的实验模型研究

目的 探讨股骨隐蔽性高能量骨折骨痂形成障碍实验模型的建立及骨痂形成障碍的预防方法.方法 取成年犬20只,随机分为A、B两组,每组10只.造成闭合的左侧股骨横断形或短斜形骨折,手持骨折两端,用两骨折端沿骨干纵轴方向平行刺伤骨膜及邻近肌肉10次,刺伤深度为骨端重迭1.5 cm.A组立即行切开复位8孔钢板内固定.B组先行手法复位经皮经大转子细克氏针临时固定,10d后行切开复位8孔钢板内固定.分别于术后2、4、6、8、12周每组各处死2只犬,取出骨折标本,行大体和组织切片观察骨痂生长情况.并于术后3、6、9、12周行患侧X线片检查. 结果 大体及组织学观察结果显示:A组动物术后2周骨折处可见坏死渗液腔;术后4周渗液腔缩小,骨端发白,无组织覆盖;术后6周骨端已无渗液,骨端吸收;术后8 ～12周无任何内、外骨痂生长,骨端进一步吸收,骨生长活动完全停滞,成功建立股骨骨痂形成障碍的实验模型.B组术后2周可见侧方骨痂的芽生,术后4周直接骨痂开始芽生,术后6周直接骨痂开始会合,术后8～12周产生正好填平骨折间隙的骨痂愈合.术后12周X线片亦显示:A组骨端萎缩吸收,骨折间隙增宽;B组断端骨痂桥接稳定. 结论 本研究成功建立了早期切开复位内固定所引发的股骨隐蔽性高能量骨折骨痂形成障碍的实验模型.延期手术可以预防骨痂形成障碍.     

雌激素对去势SD雌性大鼠骨折愈合影响的实验研究

为初步探讨雌激素与骨折愈合关系及其作用机制,采用SD雌性大鼠,分为A、B、C三组,后两组去势,21d后造成动物左胫腓骨闭合骨折,C组用雌激素处理,于不同时期分别行AKP测定、组织学检查、X线检查及红外光谱测定。结果显示:骨痂形成早期B组软骨骨痂较另两组稍多,但各组骨痂成熟程度无显著差异,骨痂形成后期B组骨痂疏松,而C组小梁粗大,呈编织、板层化趋势。可见,雌激素在SD雌性大鼠骨折愈合早期起重要调节作用,骨痂形成早期轻度抑制软骨骨痂形成,骨痂形成后期促进小梁骨增生及其向编织骨的转化。     

转化生长因子β1联合自体骨髓移植治疗兔桡骨骨折延迟愈合

目的探讨TGF-β1局部注射联合经皮自体骨髓移植对骨折愈合的促进作用。方法预制新西兰大耳白兔骨延迟愈合模型,将40只新西兰白兔随机分为A、B、C和D组,每组10只。每组分别在骨缺损模型建立后5天和10天于骨延迟愈合区注入自体血液2ml加生理盐水1ml;自体红骨髓2ml加生理盐水1ml;自体血液2ml加TGF-β11ml(100μg);自体红骨髓2ml加TGF-β11ml治疗。术后4周行组织学观察和骨痂内骨系细胞立体定量分析;术后8周行骨几何参数和骨密度(骨痂处)测定,骨生物力学测试和单位质量骨痂中钙含量测定。结果 D组成骨细胞的平均体积密度、骨痂厚度改变、钙含量、骨折愈合处的最大抗弯强度、极限应力、极限刚度和极限负荷时的能量吸收,均非常显著性高于A组(P<0.01),显著性高于B组和C组(P<0.05)。结论 TGF-β1局部注射联合经皮自体骨髓移植,是治疗骨折延迟愈合的一种有效方法。     

细微运动对长骨干骨折愈合的作用——动物实验系列研究初步总结

新西兰兔108只,造成股骨中段骨折用髓针内固定86只;胫骨中段骨折用钢板螺钉内固定22只,随机分成三组。A组用脉冲电流刺激仪刺激肌肉收缩,B组用脉冲机械振动仪振动骨折段,C组是对照组。实验结果显示:骨折肢体的血流,骨痂的钙和镁元素,GH、B_2m、AKP和低分子蛋白定量,以及骨折愈合的刚度和强度,实验组A、B均较对照组高,骨折愈合快。临床启示:骨折内固定后接受细微运动而产生骨折段内应变,能促进骨折愈合。     

髓内钉内固定或单臂外固定支架外固定加植骨治疗肱骨干骨折骨不愈合

目的 探讨髓内钉内固定加植骨与单臂外固定支架外固定加植骨两种方式治疗肱骨干骨折骨不愈合的疗效。方法将35例肱骨干骨折骨不愈合患者分为两组,19例行髓内钉内固定加植骨术（A组）,16例行单臂外固定支架外固定加植骨术（B组）。比较两组患者的影像学愈合时间、并发症、肱骨短缩和DASH评分。结果患者均获随访,时间13～28（16±4）个月。影像学愈合时间：A组（6．2±0．8）个月,B组（5．5±0．9）个月。DASH评分：A组（22．9±3．6）分,B组（24．1±3．2）分。两组比较差异无显著性（P〉0．05）。结论髓内钉内固定或单臂外固定支架外固定加植骨治疗肱骨干骨折骨不愈合均可获得满意疗效。     

形状记忆锯齿臂环抱内固定器固定后骨折愈合的动物实验观察

以镍钛形状记忆合金制成锯齿臂环抱内固定器作犬股骨干骨折固定,对骨折愈合过程中外骨痂和连接骨痂行组织学观察.结果表明骨折为典型的Ⅱ期骨折愈合:固定1月后可见明显外骨痂,骨痂内多为典型编织骨结构,胶原纤维稀疏、紊乱;术后2月骨痂量更多,骨痂的不少部位已转化为板层骨,胶原纤维趋向密集整齐;术后3月骨痂已为板层骨结构,已有哈氏系统形成.作者认为,该内固定器消除了骨折端的剪切力和扭转力,保留了压缩应力,同时对髓内血管、骨内膜无损伤,有利于骨折愈合,为长骨干骨折的内固定治疗提供了一种新方法.     

CYR61 (CCN1) protein expression during fracture healing in an ovine tibial model and its relation to the mechanical fixation stability.

The formation of new blood vessels is a prerequisite for bone healing. CYR61 (CCN1), an extracellular matrix-associated signaling protein, is a potent stimulator of angiogenesis and mesenchymal stem cell expansion and differentiation. A recent study showed that CYR61 is expressed during fracture healing and suggested that CYR61 plays a significant role in cartilage and bone formation. The hypothesis of the present study was that decreased fixation stability, which leads to a delay in healing, would lead to reduced CYR61 protein expression in fracture callus. The aim of the study was to quantitatively analyze CYR61 protein expression, vascularization, and tissue differentiation in the osteotomy gap and relate to the mechanical fixation stability during the course of healing. A mid-shaft osteotomy of the tibia was performed in two groups of sheep and stabilized with either a rigid or semirigid external fixator, each allowing different amounts of interfragmentary movement. The sheep were sacrificed at 2, 3, 6, and 9 weeks postoperatively. The tibiae were tested biomechanically and histological sections from the callus were analyzed immunohistochemically with regard to CYR61 protein expression and vascularization. Expression of CYR61 protein was upregulated at the early phase of fracture healing (2 weeks), decreasing over the healing time. Decreased fixation stability was associated with a reduced upregulation of the CYR61 protein expression and a reduced vascularization at 2 weeks leading to a slower healing. The maximum cartilage callus fraction in both groups was reached at 3 weeks. However, the semirigid fixator group showed a significantly lower CYR61 immunoreactivity in cartilage than the rigid fixator group at this time point. The fraction of cartilage in the semirigid fixator group was not replaced by bone as quickly as in the rigid fixator group leading to an inferior histological and mechanical callus quality at 6 weeks and therefore to a slower healing. The results supply further evidence that CYR61 may serve as an important regulator of bone healing.     

微型钛板与记忆合金环抱器治疗掌指骨骨折的对比研究

目的对比分析微型钛板内固定和记忆合金环抱器内固定治疗掌指骨（近中节指骨）骨折的临床疗效。方法采用微型钛板治疗组（A组）66例104处及记忆合金治疗组（B组）61例92处,对比分析两种手术治疗效果。随访3～12个月,平均6个月,以TAFS评分为评价标准,并记录伤口感染、骨折愈合时间、骨折延迟愈合、骨不连、关节僵硬、肌腱粘连、内置物外露等并发症发生情况。结果127例均达骨性愈合。A组（104处骨折）优良率93．29％,B组（92处骨折）,优良率79．9％。两组TAFS功能评分结果差异有统计学意义（芹=4．14,P〈0．05）,A组明显优于B组。A组延迟愈合3处（2．88％）;B组延迟愈合7处（7．59％）。B组病例延迟愈合率高于A组。A组骨折愈合时间平均31．5d：B组骨折愈合时间平均54．6d。无骨不连发生。两组结果差异有统计学意义（t=2．23,P〈0．05）,A组骨折愈合时间明显短于B组,两组术后感染率无差异。结论微型钛板治疗掌指骨骨折在术后关节功能恢复情况、骨折愈合时间、骨折延迟愈合、关节僵硬、肌腱粘连、内置物外露等并发症发生指标上明显优于记忆合金环抱器治疗组．是目前掌指骨骨折较为理想的治疗方法。     

Effect of recombinant human osteogenic protein-1 on the healing of a freshly closed diaphyseal fracture

Osteogenic protein-1 (OP-1), or bone morphogenetic protein-7, is an osteoinductive morphogen that is involved in embryonic skeletogenesis and in bone repair. In bone defect models without spontaneous healing, local administration of recombinant human OP-1 (rhOP-1) induces complete healing. To investigate the ability of rhOP-1 to accelerate normal physiologic fracture healing, an experimental study was performed. In 40 adult female goats a closed tibial fracture was made, stabilized with an external fixator, and treated as follows: (1) no injection; (2) injection of 1 mg rhOP-1 dissolved in aqueous buffer; (3) injection of collagen matrix; and (4) injection of 1 mg rhOP-1 bound to collagen matrix. The test substances were injected in the fracture gap under fluoroscopic control. At 2 and 4 weeks, fracture healing was evaluated with radiographs, three-dimensional computed tomography (CT), dual-energy X-ray absorptiometry, biomechanical tests, and histology. At 2 weeks, callus diameter, callus volume, and bone mineral content at the fracture site were significantly increased in both rhOP-1 groups compared with the no-injection group. As signs of accelerated callus maturation, bending and torsional stiffness were higher and bony bridging of the fracture gap was observed more often in the group with rhOP-1 dissolved in aqueous buffer than in uninjected fractures. Treatment with rhOP-1 plus collagen matrix did not result in improved biomechanical properties or bony bridging of the fracture gap at 2 weeks. At 4 weeks there were no differences between groups, except for a larger callus volume in the rhOP-1 plus collagen matrix group compared with the control groups. All fractures showed an advanced stage of healing at 4 weeks. In conclusion, the healing of a closed fracture in a goat model can be accelerated by a single local administration of rhOP-1. The use of a carrier material does not seem to be crucial in this application of rhOP-1.     

The effect of PTH(1‐34) on fracture healing during different loading conditions

Parathyroid hormone (PTH) and PTH(1‐34) have been shown to promote bone healing in several animal studies. It is known that the mechanical environment is important in fracture healing. Furthermore, PTH and mechanical loading has been suggested to have synergistic effects on intact bone. The aim of the present study was to investigate whether the effect of PTH(1‐34) on fracture healing in rats was influenced by reduced mechanical loading. For this purpose, we used female, 25‐week‐old ovariectomized rats. Animals were subjected to closed midshaft fracture of the right tibia 10 weeks after ovariectomy. Five days before fracture, half of the animals received Botulinum Toxin A injections in the muscles of the fractured leg to induce muscle paralysis (unloaded group), whereas the other half received saline injections (control group). For the following 8 weeks, half of the animals in each group received injections of hPTH(1‐34) (20 µg/kg/day) and the other half received vehicle treatment. Fracture healing was assessed by radiology, dual‐energy X‐ray absorptiometry (DXA), histology, and bone strength analysis. We found that unloading reduced callus area significantly, whereas no effects of PTH(1‐34) on callus area were seen in neither normally nor unloaded animals. PTH(1‐34) increased callus bone mineral density (BMD) and bone mineral content (BMC) significantly, whereas unloading decreased callus BMD and BMC significantly. PTH(1‐34) treatment increased bone volume of the callus in both unloaded and control animals. PTH(1‐34) treatment increased ultimate force of the fracture by 63% in both control and unloaded animals and no interaction of the two interventions could be detected. PTH(1‐34) was able to stimulate bone formation in normally loaded as well as unloaded intact bone. In conclusion, the study confirms the stimulatory effect of PTH(1‐34) on fracture healing, and our data suggest that PTH(1‐34) is able to promote fracture healing, as well as intact bone formation during conditions of reduced mechanical loading. © 2013 American Society for Bone and Mineral Research.     

Initial vascularization and tissue differentiation are influenced by fixation stability.

Fracture healing requires a certain degree of mechanical stability and an adequate blood supply. The hypothesis of the present study was that increased interfragmentary shear leads to a reduced initial vascularization and prolonged healing. The aim of the study was to quantitatively analyze the histological appearance of vascularization and tissue differentiation with regard to fracture stability during the course of healing. A mid-shaft osteotomy of the tibia was performed in two groups of sheep and stabilized with either a rigid or semirigid external fixator, differing in bending stiffness. Interfragmentary movements and ground reaction forces were evaluated in vivo during a 9-week period. The sheep were sacrificed at 2, 3, 6, and 9 weeks postoperatively. The tibiae were tested biomechanically and histological sections from the callus were prepared for analysis of tissue differentiation and vascularization. Larger interfragmentary shear movements in the semirigid fixator group were associated with a reduced initial blood supply. At 6 weeks the semirigid fixator group showed a significantly lower percentage of mineralized bone and a higher amount of fibrous tissue leading to a significantly lower stiffness of the callus than the rigid fixator group. This initial delay in healing was compensated for in the later stages with the production of greater volumes of callus tissue so that both groups showed the same callus stiffness at 9 weeks. However, the rigid fixator group showed signs of the beginning of callus remodeling at the latest time points suggesting a faster bone healing. The results indicate the important role of the initial mechanical stability specifically in the vascularization of an osteosynthesis. Further studies should illustrate the precise role of mechanical conditions on the regulation of angiogenesis during early bone healing.     

镍-钛记忆环抱器治疗四肢骨折

目的 探讨记忆环抱器治疗四肢骨折的特点、机理与疗效。方法 对2001年5月～12月收治的97例患回顾性分析：锁骨骨折54例，尺、桡骨骨折30例，腓骨中下段骨折5例，肱骨骨折4例，股骨骨折3例，跖骨骨折1例。骨折通过切开复位，镍．钛记忆环抱器固定，体部置于张力侧。单纯骨折不用外固定。结果 97例患随访9～16月，均于术后3～10周达到临床愈合。54例于3～6月完全骨性愈合。结论 镍-钛记忆环抱器用于四肢骨折内固定，具有手术简单、时间短、固定牢固、骨折端血运破坏少、骨折愈合快、可早期功能锻炼，是一种治疗骨折的好方法。     

Mechanical stimulation by external application of cyclic tensile strains does not effectively enhance bone healing

OBJECTIVE: To determine whether an externally induced interfragmentary movement enhances the healing process of a fracture under flexible fixation. DESIGN: Randomized, prospective in vivo animal study with control group. Twenty-four skeletally mature Merino sheep were randomly assigned to six groups of four animals, which received cyclic interfragmentary movements of 0.2 and 0.8 millimeters and stimulation frequencies of 1, 5, and 10 Hertz, respectively. Twelve animals did not receive any externally applied stimulation and served as a control group. SETTING: Unrestricted stall activity with weight bearing reduced by tenotomy of the Achilles tendon. INTERVENTIONS: Osteotomy of the tibial diaphysis with three-millimeter gap width fixed with a six-pin, monolateral, double-bar external fixator. Interfragmentary movement of the osteotomy gap was externally induced by a motor-driven actuator unit. Five hundred cycles inducing nonuniform tensile strains within the gap were performed each day. MAIN OUTCOME MEASUREMENTS: Nine weeks after surgery, the animals were killed, and bone mineral density and callus cross-sectional area were measured with quantitative computed tomography. Callus projectional area was assessed by radiographs, and mechanical stability was determined with a three-point bending test. RESULTS: External stimulation with nonuniform cyclic tensile strains did slightly affect but not significantly enhance the fracture healing process. Varying the stimulation frequency had no influence on the healing process. The stimulation with 0.8 millimeter displacement magnitude resulted in a larger periosteal callus, but a decreased bone mineral density compared with the 0.2-millimeter displacement magnitude. The stimulation had no significant influence on the mechanical properties of the healing bone. CONCLUSIONS: Induced cyclic tensile strains did not produce a relevant enhancement of bone healing under flexible fixation.     

Staphylococcus aureus peptidoglycan impairs fracture healing: an experimental study in rats.

Staphylococcus aureus is the common organism causing musculoskeletal infections. Staphylococcus aureus peptidoglycan (SaPG) has been identified to increase the acute inflammatory response to wounding, increase reparative granulation tissue, and improve healing. The healing of bone fractures is a balanced process of granulation tissue that is calcified to obtain increasing stability. By increasing reparative collagen accumulation, however, SaPG may induce a shift towards immature fibrous callus production. Therefore, it was our hypothesis that SaPG would impair bone healing after fracture. In three groups, each of nine rats, a mid-diaphyseal osteotomy/fracture of the femoral bone was performed and then nailed. In one group of animals, SaPG was applied locally at the fracture site, and in another group SaPG was applied intraperitoneally (systemically). Control littermate received saline. The animals were sacrificed after 6 weeks, and the mechanical characteristics of the healing osteotomies were evaluated. We found that application of SaPG locally induced a hypertrophic and immature callus as evaluated by callus production, by bone mineral content and density, and by bending moment and rigidity. In the rats given SaPG intraperitoneally, bone healing went uneventful compared to the control rats. Collectively, these data show that SaPG induces an alteration in the normal bone healing response towards a less calcified callus production.     

Strontium Is Incorporated into the Fracture Callus but Does Not Influence the Mechanical Strength of Healing Rat Fractures

Strontium ranelate (SrR) is a new agent used in the treatment of osteoporosis and is suggested to reduce bone resorption and increase bone formation. We investigated whether SrR influences the macro- and nanomechnical properties of healing fractures in rats. A closed tibia fracture model was used to study fracture healing in rats after 3 and 8 weeks of healing. Two groups of rats were treated with SrR (900 mg/kg/day) mixed into the food, while two groups served as control animals. The healing fractures were investigated by three-point bending, dual energy X-ray absorptiometry, energy-dispersive X-ray spectroscopy (EDX), and nanoindentation. There was a 100-fold increase (P < 0.001) in serum Sr after 3 and 8 weeks of SrR treatment. The callus volume was significantly higher in the SrR-treated group than in control animals (P < 0.01) after 3 weeks of healing. This was accompanied by a significant increase in callus bone mineral content (P < 0.05). However, after 8 weeks of healing, no difference was found in either callus volume or bone mineral content. SrR did not influence maximum load or stiffness of the fractures after either 3 or 8 weeks of healing. EDX showed that Sr was incorporated into the callus; however, this did not influence the nanomechanical properties. In conclusion, SrR stimulates callus formation but has no effect on callus remodeling. Sr is incorporated into the newly formed callus tissue, but this has no deteriorating effect on the mechanical properties of rat tibial fractures at either the macroscopic or nanoscopic level after 3 or 8 weeks of healing.