Effects of torsional rigidity on fracture healing: strength and mineralization in rat femora

OBJECTIVE: To assess the effects of torsional rigidity and dynamization on fracture healing in a medullary nailed rat femoral model. STUDY DESIGN: Randomized study in male Wistar rats with a diaphyseal osteotomy/fracture. METHODS: Reamed cannulated nailing was performed in sixty rats. One group (twenty rats) received unlocked nails (UL group) and another group received nails with proximal and distal locking that was dynamized after twenty days (DL group). The third group was statically locked (SL group). A fourth group of twenty rats served as the control group. After randomization, the femurs of ten rats in each group at six and twelve weeks were studied clinically, radiologically, and biomechanically, and bone mineralization was measured by dual-energy x-ray absorptiometry (DEXA). RESULTS: Radiographs in two planes revealed clearly visible fractures at six weeks, and at twelve weeks bridging callus was apparent in all three treatment groups. The callus area in the UL group was significantly larger at six weeks than in the other groups, and at twelve weeks the UL and DL groups had larger callus areas than the SL group. Biomechanically, UL nails had reduced maximum bending load at six and twelve weeks, while DL nails had increased fracture energy at six weeks compared with SL nails. Bone mineral content and bone mineral density in the callus segment and diaphysis were increased with DL nails at six weeks. CONCLUSION: This animal study indicates that (a) interlocked nailing has a beneficial effect on bone healing and (b) although dynamization may have a beneficial effect on the quality of early bone healing, (c) dynamization does not increase the rate of bony union. The clinical implication is that routine early dynamization of locked femoral fractures may not be indicated, reserving dynamization to cases of delayed union.     

Optimization of intramedullary nailing by numerical simulation of fracture healing

Due to the annular gap between intramedullary (IM) nails and the endosteal surface, high interfragmentary movement can occur under loading. This could prolong the healing time, particularly for thin IM nails that are often used for unreamed IM nailing. The aims of our study were to determine the influence of the nail diameter on the healing time of human tibial shaft fractures and to investigate whether the healing time could be shortened by increasing the stiffness of the implant material. Therefore, a corroborated numerical model for simulating the fracture healing process in humans was used to simulate the healing process of human tibial fractures treated with IM nails. The calculated healing time (up to 71 weeks) was longest for transverse fractures treated with thin IM nails made of titanium. That the healing time was disproportionately long depended on the nail diameter, and could be greatly reduced by using a thicker nail or using steel instead of titanium. To avoid a prolonged healing time, the nail should be thick, and the annular gap should be as narrow as possible. Alternatively, using steel instead of titanium may also help to avoid a prolonged healing time.     

The effect of aging on fracture healing in the rat

Summary The effect of age on the biomechanical properties of healing tibial fractures was studied by comparing the fracture healing in 2-year-old male Wistar rats with the fracture healing in 3-month-old male Wistar rats after 40 and 80 days of healing. There were no significant differences in the mechanical parameters after 40 days of healing, but after 80 days, a considerable delay in the fracture healing process was noted in the old rats compared with the young adult rats when evaluated by maximum load, maximum stress, stiffness, and energy absorption in a three-point bending procedure. In the contralateral, nonfractured bones, the tibiae from the old animals sustained higher loads and had higher stiffness than the bones from the young adult animals, but stress values, elastic modulus, and capacity for energy absorption was much lower in the old animals.     

Rupture of the extensor pollicis longus tendon following dorsal entry flexible nailing of radial shaft fractures in children

Introduction

Diaphyseal forearm fractures are common in children and adolescents. Intramedullary fixation with flexible nails has a high success rate. Complications related to the insertion of the radial nail include injury to the superficial branch of the radial nerve and rupture of the extensor pollicis longus (EPL) tendon.

Materials and Methods

We report a series of nine patients who sustained an EPL injury related to the insertion of an elastic intramedullary nail into the radius.

Results

All nine patients underwent operative management, consisting of either EPL release, EPL direct repair, or tendon transfer (using extensor indicis proprius). In all cases, the nail entry site was directly related to the location of EPL. In many of the cases the EPL dysfunction occurred early on but it’s recognition was often delayed.

Conclusion

Based on our findings, we recommend the use of a radial entry point. For surgeons who prefer the dorsal entry point, we recommend that they use an incision which allows visualisation of the extensor tendons and that any post-operative EPL dysfunction is addressed promptly.     

Fracture healing after reamed and unreamed intramedullary nailing in sheep tibia

Intramedullary nailing is a well-established method for stabilisation of long-bone shaft fractures. It is still a controversy as to whether the procedure should be done by an unreamed or reamed technique.In the present animal study, 24 sheep were treated with intramedullary nailing. Midshaft fractures (Arbeitsgemeinschaft für Osteosynthese (AO) type 42-A2/3) were created. Eight sheep were treated with an unreamed nailing technique (UN), a further eight sheep underwent tibia nailing by the reamed technique using the conventional AO reaming system (RC) and in a further eight sheep, reamed nailing was performed using an experimental reaming system (RE). Intra-operatively, the intramedullary pressure was measured and, during a healing time of 10 weeks, the growth of callus formation was labelled with fluorescence markers after 4 and 6 weeks. After 10 weeks, the animals were euthanised and the quality of fracture healing was determined by recording stiffness in torsion, antero-posterior and mediolateral bending and the load at yield. In addition, the callus formation at the fracture zone was evaluated by fluorescence microscopy and macroradiographs.The results showed a decrease of intramedullary pressure when reamed nailing was performed with the RE (72.5 mmHg) system compared with the conventional AO reaming system (227 mmHg). Mechanical testing did not reveal any significant differences either for torsional or bending stiffness or for load at yield for any of the three procedures. Histological evaluation showed a similar callus formation for the UN group and the RE group. Callus formation in the UN (65 mm²) and RE (63 mm²) groups showed a higher increase during the first 6 weeks than those treated with the conventional AO reaming system (27 mm²). This means that, especially during the first weeks of fracture healing, damage to the bone by the reaming process can be reduced by reaming with a reaming device with lowered cutting flutes and smaller drive-shaft diameter.Intramedullary pressure can be significantly reduced by using reaming systems with reduced drive-shaft diameters and deepened cutting flutes. In the early phase of fracture healing, callus formation can be influenced positively when using the RE system.     

Low-dose X-irradiation promotes mineralization of fracture callus in a rat model

Objectives  This study investigated the hypothesized beneficial effect of low-dose irradiation (LDI) on fracture callus mineralization in a rat model. Methods  Seventy-two male Sprague–Dawley rats were averagely randomized into LDI group (rats treated with LDI) and SHAM group (rats treated with sham irradiation). Right after either LDI or sham irradiation, a standardized closed fracture on the right femur was established. At 2, 3 and 4 weeks postfracture, 12 rats in each group were euthanized. Fracture callus was assessed by using radiography and MicroCT for callus bridging, peripheral quantitative computed tomography (pQCT) for quantifying bone mineral content (BMC) and cross sectional area (CSA), confocal laser scanning microscopy for measuring area fraction of fluorescence labeling (AFFL) and four-point bending test for examining mechanical properties. Results  The CSA and AFFL were found to be 22 and 33% smaller in the LDI group compared to the SHAM group at 2 weeks (P < 0.05 for both), whereas the BMC and AFFL were 15 and 34% higher in the LDI group at 3 weeks (P < 0.05 for both). The changing patterns were consistent with the findings in 3-D MicroCT reconstructions. The mechanical parameters (Max-Load, Stiffness and Energy) were also 18, 30 and 24% higher in the LDI group than in the SHAM group at 3 weeks (P < 0.05 for all). At 4 weeks, there was no difference found for all assessments between the two groups. Conclusion  The results indicated LDI promoted mineralization at the stage of hard callus formation in a rat fracture model.     

Tobacco extract but not nicotine impairs the mechanical strength of fracture healing in rats.

The influence of nicotine and tobacco extract (without nicotine) alone and in combination on and mechanical strength of closed femoral fractures in rats was investigated. One hundred four male Sprague-Dawley rats were divided into four groups receiving: nicotine, tobacco extract, tobacco extract plus nicotine, and saline. One week prior to fracture, osmotic pumps were implanted subcutaneously in all animals to administer nicotine equivalent to the serum level of nicotine observed in a smoker consuming one to two packs of cigarettes daily. An equivalent volume of saline was administered to the control animals. Tobacco extract was administered orally. A closed transverse femoral diaphysial fracture was performed, and stabilized with an intramedullary pin. The fractures were mechanically tested after 21 days of healing. Tobacco extract alone decreased the mechanical strength. Ultimate torque and torque at yield point of the tobacco extract group were decreased by 21% (p=0.010) and 23% (p=0.056), respectively, compared with the vehicle (saline) group, and by 20% (p=0.023) and 26% (p=0.004), respectively, compared with the nicotine group. No difference was found between the tobacco extract and tobacco extract plus nicotine groups. An 18% (p=0.013) reduction in torque at yield point was observed in the tobacco extract plus nicotine group compared with the nicotine group. No differences in ultimate stiffness, energy absorption, and callus bone mineral content at the fracture line were found between any of the groups. Serum levels of nicotine were between 40-50 ng/mL in the group given nicotine alone and the group given tobacco extract plus nicotine (equivalent to serum levels observed in persons smoking one to two packs of cigarettes per day).     

Immediate versus delayed intramedullary nailing for open fractures of the tibial shaft: A multivariate analysis of factors affecting deep infection and fracture healing

Background:

The purpose of this study was to evaluate contributing factors affecting deep infection and fracture healing of open tibia fractures treated with locked intramedullary nailing (IMN) by multivariate analysis.

Materials and Methods:

We examined 99 open tibial fractures (98 patients) treated with immediate or delayed locked IMN in static fashion from 1991 to 2002. Multivariate analyses following univariate analyses were derived to determine predictors of deep infection, nonunion, and healing time to union. The following predictive variables of deep infection were selected for analysis: age, sex, Gustilo type, fracture grade by AO type, fracture location, timing or method of IMN, reamed or unreamed nailing, debridement time (≤6 h or >6 h), method of soft-tissue management, skin closure time (≤1 week or >1 week), existence of polytrauma (ISS< 18 or ISS≥18), existence of floating knee injury, and existence of superficial/pin site infection. The predictive variables of nonunion selected for analysis was the same as those for deep infection, with the addition of deep infection for exchange of pin site infection. The predictive variables of union time selected for analysis was the same as those for nonunion, excluding of location, debridement time, and existence of floating knee and superficial infection.

Results:

Six (6.1%; type II Gustilo n=1, type IIIB Gustilo n=5) of the 99 open tibial fractures developed deep infections. Multivariate analysis revealed that timing or method of IMN, debridement time, method of soft-tissue management, and existence of superficial or pin site infection significantly correlated with the occurrence of deep infection (P< 0.0001). In the immediate nailing group alone, the deep infection rate in type IIIB + IIIC was significantly higher than those in type I + II and IIIA (P = 0.016). Nonunion occurred in 17 fractures (20.3%, 17/84). Multivariate analysis revealed that Gustilo type, skin closure time, and existence of deep infection significantly correlated with occurrence of nonunion (P < 0.05). Gustilo type and existence of deep infection were significantly correlated with healing time to union on multivariate analysis (r² = 0.263, P = 0.0001).

Conclusion:

Multivariate analyses for open tibial fractures treated with IMN showed that IMN after EF (especially in existence of pin site infection) was at high risk of deep infection, and that debridement within 6 h and appropriate soft-tissue managements were also important factor in preventing deep infections. These analyses postulated that both the Gustilo type and the existence of deep infection is related with fracture healing in open fractures treated with IMN. In addition, immediate IMN for type IIIB and IIIC is potentially risky, and canal reaming did not increase the risk of complication for open tibial fractures treated with IMN.     

骨质疏松性骨折愈合与骨量、骨结构及力学性能相关性的实验研究

目的探明骨质疏松性骨折愈合程度与骨量、骨结构与力学性能的相互关系,以期能为临床治疗提供科学指导与理论依据.方法选择8月龄雌性SPF级SD大鼠130只,随机分为2组：骨质疏松性骨折组（OPFM）与一般性骨折组（CFM）,每组各65只.手术方法建立骨质疏松性骨折与一般性骨折的实验模型,于术后1、2、4、6、8、12、16周作骨痂组织形态计量学、骨密度与力学性能测试等观察.结果①骨痂组织骨组织形态计量学结果发现：OPFM组成熟小梁骨占骨痂面积比CFM组小,且小梁骨厚度变薄、小梁骨间距较宽;同时骨小梁动力学参数显示：OPFM组骨小梁表面荧光标记百分比（LS）较CFM组低,而骨矿化沉积率（MAR）却较高.②骨密度（BMD）测定显示：两组BMD值8周时均达到高峰（P＞0.5）,随后均降低,OPFM组下降尤为明显;12周时两组间差异有显著性（P＜0.05）.③骨痂组织扭转力学强度测试结果表明：8、12周OPFM组扭转强度均较CFM组低.结论在骨质疏松性骨折修复过程中,骨痂组织的有机成份组成、显微结构、骨矿代谢与骨量的异常改变导致了其力学强度乃至骨折愈合质量的降低,是再次骨折发生的主要原因.     

Vascular reorganization and return of rigidity in fracture healing

The present study addresses the relationship between vascular reorganization and the biomechanical changes occurring during canine long bone fracture healing. A middiaphyseal osteotomy of the radius was performed, and angiographic studies were carried out using India ink injections from 2 to 12 weeks postosteotomy. The radii were harvested, subjected to nondestructive four-point bend testing on an Instron, and then sectioned and cleared according to the Spaltholtz technique. The observed microangiographic patterns were correlated with the calculated rigidity values. Quantitative bone blood flow measurements around the osteotomy were performed on a different group of animals, using the radiotracer microsphere technique, at 3, 6, and 9 weeks postosteotomy to correlate with our qualitative microangiographic results. We demonstrated a direct and predictable relationship between the phase of vascular reorganization and the rigidity. This correlation was present even in our delayed union specimens.     

Role of dual energy X-ray absorptiometry in monitoring fracture healing in a rat femoral fracture model

Earlymobilizationandweightbearingplayimportantrolesinminimizingtheamountofbonelosstoachievegoodhealingafterbonefracture.1Areliableandnoninvasivemethodforevaluatingfracturehealingcannotonlyhelpdecidewhentostarweightbearing, butalsohelpdetecttheimpairedboneunionearlytopreventdelayedunionsornonunions.However, objectivequantitativemethodsforearlyevaluationoffracturehealinghavenotbeendevelopedyet. DualenergyX rayabsorptiometry(DEXA)isoneofthemostaccuratemethodsformeasuringbonemassinvivo. Itismain…     

去势对骨折早期愈合过程的影响

目的 通过对去势大鼠股骨骨折模型愈合早期骨痂的组织学、骨密度以及转化生长因子β1(Transforming growth factor beta 1.TGF-β1)、碱性成纤维细胞生长因子(basic fibroblast growth factor,bFGF）、骨形态发生蛋白-2(bone morphogenetic proteins-2，BMP-2)合成变化的观察．探讨骨质疏松骨折早期愈合过程的变化。方法 将60只雌性SD大鼠分为去势组和对照组，3个月后制成股骨干骨折模型．伤后不同阶段处死．分别进行组织学、骨密度以及TGF-β1,bFGF,BMP-2免疫组化染色方法观察。结果 大鼠去势后3个月全身骨密度检查证实去势组骨质疏松形成。骨折后第3d两组均开始形成原始骨痂；第4～6周，去势组骨痂比对照组少，且软骨痂比例较高．骨密度较低，免疫组化染色显示，在两组间bFGF、BMP-2的表达与分布、高峰出现与持续时间差异无显著性．去势组骨小梁附近表达TGF-β1的成骨细胞数目减少，结论 骨质疏松使大鼠骨折早期骨痂的数量与质量降低，自软骨性骨痂至骨性骨痂演变过程减缓．对骨折愈合过程的影响与BMP-2、bFGF的表达无明显关联。TGF-β1在成骨细胞中的表达减少可能是引起骨质疏松骨折愈合质量下降的因素之一．     

Effect of autocontrol micromotion intramedullary interlocking nail on fracture healing： an experimental study

Objective: To investigate the effect of autocontrol micromotion locking nail ( AMLN ) on experimental fracture healing and its mechanism. Methods: 16 goats undergoing both sides of transverse osteotomy of the femoral shafts were fixed intramedullary with AMLN and Gross-Kempf (GK) nail, respectively. The follow-up time was 7, 14, 28 and 56 days. Roentgenographic, biomechanical, histological, scanning electromicroscopic and biochemical analyses were done. Results: (1) The strength of anticompression, antiflexion and antitorsion in the fractural end in the AMLN-fixed group was higher than that of GK nail-fixed group; whereas, the rate of stress shelter in the fractured end decreased significantly (P<0.01). (2) The content of the total collagen, insoluble collagen, calcium and phosphate in the AMLN-fixed group was higher than that in the GK nail-fixed group (P<0.05). (3) Histological observation and quantitative analysis of calluses revealed that AMLN could promote the growth of bridge calluses and periosteum calluses. Hence the facture healing and remolding process achieved early, which was much better than traditional GK nail fixation. (P<0.05). (4) 7-14 days postoperation, the calluses of AMLN-fixed group was flourish and camellarly arranged and the collagen fibril formed constantly in the absorption lacuna of bone trabecula. 28-56 days postoperation, the collagen fibril was flourish around the absorption lacuna and was parallel to the bone's longitudinal axis. Active bony absorption and formation were seen, so was remolding and rebuilding. Haversian system was intact and the bony structural net was very tenacious because of the deposition of calcium salt. None of the above findings was observed in the GK nailfixed group. Conclusions: The design of AMLN accords well with the plastic fixation theory. As the geometry ametabolic system constituted by the intramedullary fixation instruments and the proximal and distal end of the fracture is very firm and stable, the disturbance to the physical stress distributed in the fractural end is light. The generation and conduct of the intermittent physical stress between the fractural parts could reach the balance between stress conduct and stress protection. The feature that the healing and remolding take place at the same time speeds up the fractural healing process.     

Early period of fracture healing in ovariectomized rats

Objective. To evaluate the effect of osteoporosis on fracture healing through observing the hlstomorphological changes, bone mineral density of callus and expression and distribution of transforming growth factor beta 1 (TGF-β1 ), basic fibroblast growth factor (bFGF)and bone morphogenetic protein.2 (BMP-2) in ovariectomized rats. Methods. Sixty female Sprague-Dawley rats ( aged 12 weeks and weighing 235 g on average ) were randomly divided into an ovariectomized (OVX) group (n =30) anda sham-operated (SO) group ( n = 30). Ovariectomy was performed in the OVX rats and same incision was made in the SO rats. Three months later, fracture of femoral shaft was made on all the rats. Then they were killed at different time points. Callus formation was observed with histological and imethods. Results: A reduction in callus and bone mineral density in the healing femur and a decrease of osteoblasts expressing TGF-β1 near the bone trabecula were observed in the OVX rats 3-4 weeks after fracture.Histomorphological analysis revealed a higher content of soft callus in the OVX rats than that in the SO rats.Immunohistochemistry results showed that no remarkable difference in expression and distribution of BMP-2 and bFGF between the OVX and SO groups was found. Conclusions: Osteoporosis influences the quantity and quality of callus during the early period of fracture healing. The effect of osteoporosis on fracture healing has no relationship with the expression of BMP-2 or bFGF. The decreased expression of TGF-I31 in osteoblasts may cause a decrease in quality of facture healing after osteoporosis.     

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.     

糖尿病大鼠骨折后血管内皮生长因子的变化

目的 观察糖尿病大鼠骨折后血管内皮细胞生长因子（VEGF）的变化。方法 70只清洁雄性Wistar大鼠随机分为对照组和链脲佐菌素（stz）诱导的速发型糖尿病组，线锯锯断两组大鼠左胫骨后复位外固定。于骨折后1、2、3、4、6、8周取静脉血保留血清；大鼠左下肢X线片观察骨折愈合情况；取骨折断端组织行HE染色光镜观察、免疫组织化学检测VEGF；酶联免疫吸附分析法（EHsa）检测血清VEGF。结果 糖尿病组4周可以看见纤维骨痂，8周才有较多骨性骨痂出现，较对照组明显滞后；HE染色镜下观察糖尿病组骨形成滞后；3周VEGF免疫组织化学灰度值两组间差异有统计学意义，（实验组142．8±3．8；对照组128．0±5．5，P〈0．01）；两组血清中VEGF差异元统计学意义（P〉0．05）。结论 糖尿病大鼠骨折后血清中VEGF未减少，局部组织VEGF含量低是导致糖尿病大鼠骨折愈合差的原因之一。     

振动力学刺激对骨质疏松性骨折愈合的影响

目的本研究旨在探讨高频率低能量的振动力学刺激对骨质疏松性骨折愈合的影响。方法59只大鼠建立大鼠卵巢切除骨质疏松模型,建模成功后构建股骨骨折模型,并随机分为振动力学刺激组和对照组。骨折后第5天开始对振动组使用高频率低能量振动平台(35Hz,峰振幅0.3重力加速度)行每天20min的振动力学刺激,对照组则行假治疗。每周摄X线片观察骨折愈合的情况,并采用显微计算机断层扫描和生物力学测试评估骨痂生成的情况及其力学属性。结果 X线随访显示,振动组的骨折愈合速度和愈合率均优于对照组。前者新生矿化骨痂的体积在治疗后第2周和第4周时均显著高于后者。第8周时,振动组成熟骨痂的体积以及整体的力学强度均显著优于对照组。结论高频率低能量振动力学刺激可促进骨质疏松性骨折的愈合。     

Effects of trypsinization and mineralization on intrasynovial tendon allograft healing to bone

The purpose of the current study was to develop a novel technology to enhance tendon‐to‐bone interface healing by trypsinizing and mineralizing (TM) an intrasynovial tendon allograft in a rabbit bone tunnel model. Eight rabbit flexor digitorum profundus (FDP) tendons were used to optimize the trypsinization process. An additional 24 FDP tendons were stratified into control and TM groups; in each group, 4 tendons were used for in vitro evaluation of TM and 8 were transplanted into proximal tibial bone tunnels in rabbits. The samples were evaluated histologically and with mechanical testing at postoperative week 8. Maximum failure strength and linear stiffness were not significantly different between the control and TM tendons. A thin fibrous band of scar tissue formed at the graft‐to‐bone interface in the control group. However, only the TM group showed obvious new bone formation inside the tendon graft and a visible fibrocartilage layer at the bone tunnel entrance. This study is the first to explore effects of TM on the intrasynovial allograft healing to a bone tunnel. TM showed beneficial effects on chondrogenesis, osteogenesis, and integration of the intrasynovial tendon graft, but mechanical strength was the same as the control tendons in this short‐term in vivo study. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:468–474, 2015.     

降钙素对卵巢切除大鼠股骨骨折愈合的影响

目的观察降钙素对卵巢切除大鼠股骨骨折愈合的作用，为临床上治疗骨质疏松性骨折提供实验依据。方法50只雌性、14周龄SD大鼠共分成5组，每组10只。分成假手术组（Sham，G1），双侧卵巢切除术组（OVX，G2），假手术＋骨折组（Sham＋F，G3），卵巢切除术＋骨折组（OVX＋F，G4），卵巢切除＋骨折＋降钙素药物组（OVX＋F＋CT，G5），骨折组大鼠均采用右股骨中段横行骨折，髓内针固定；降钙素采用皮下给药，隔日1次（16IU·kg^-1）。所有大鼠于术后4周杀死，取右侧股骨标本。然后，分别进行CR摄片、组织形态学观察，并应用双能X线骨密度仪（DEXA）测量右股骨整体、远段和中段骨密度以及BMP-2免疫组化观察，并应用病理图像分析仪对BMP-2免疫组化进行光密度测量。结果（1）OVX组与Sham组比较，BMD显著下降。（2）OVX＋F＋CT组与OVX＋F组比较：骨痂mBMD显著增高；BMP-2的表达无显著性差异。结论降钙素对OVX大鼠股骨骨折具有明显促进骨折愈合的作用，加速编织骨向板层骨的演变过程。     

BMP促进去神经后废用性骨质疏松骨折愈合的实验研究

为了观察ＢＭＰ对去神经后废用性骨质疏松性骨折愈合的作用，作考选用６月龄健康标准大鼠，严格配对分组，切除双侧坐骨神经后３周证实有明显骨质疏松。然后在腔骨人工骨折骨缺损处分别植入酸解胶状鼠尾胶原（对照）及ＢＭＰ与胶原混和物（实验组）。通过血清钙浓度、碱性磷酸酶活性及骨组织形态计量学多项参数的观察，显示ＢＭＰ对去神经后废用性骨质疏松骨折愈合有明显促进作用（Ｐ＜０．０５～０．０１）