动力髋螺钉与股骨近端髓内钉治疗老年股骨近端骨折的临床疗效比较

目的:比较动力髋螺钉与股骨近端髓内钉治疗老年股骨近端骨折的临床疗效和安全性。方法:收集我院收治的老年股骨近端骨折患者64例,随机分为DHS组和PFN组,每组各32例。DHS组患者给予动力髋螺钉的固定方式,PFN组给予股骨近端髓内钉的固定方式。手术后对患者的手术切口长度、术中出血量、手术时间、骨折愈合时间、术后并发症以及患者临床疗效进行检测并比较。结果:与治疗前相比,两组患者治疗后的Harris评分均显著下降(P0.05);与DHS组相比,PFN组患者的手术切口长度、术中出血量、手术时间、骨折愈合时间、术后并发症的发生率以及Harris评分均较低(P0.05)。结论:股骨近端髓内钉的固定治疗老年股骨近端骨折的临床疗效较好,安全性更高。     

近端膨胀髓内钉与抗旋髓内钉治疗老年股骨转子间骨折的临床疗效分析

目的:探究近端膨胀髓内钉与近端螺旋刀片抗旋髓内钉治疗老年股骨转子间骨折疗效及躁动发生率比较。方法:病例来源为2012年5月至2013年10月收入我院的老年股骨转子间骨折患者60例,采用随机数字表随机分为两组,膨胀钉组30例,采用近端膨胀髓内钉的手术方法,PFNA组30例,采用近端螺旋刀片抗旋髓内钉的手术方法。手术结束后,对两组患者进行X射线片、手术时间及出血量、髋关节功能的比较,同时对比躁动发生率。结果:X线检查结果显示两组患者经手术后骨折处均复位良好,无并发症及内固定物的脱落及松动,两组比较无显著差异(P0.05);与PFNA组相比,膨胀组患者的手术时间及出血量明显降低,差异具有统计学意义(P0.05);两组患者术后3个月、6个月的Harris评分显示,与PFNA组相比,膨胀钉组的优良率明显升高,髋关节优于PFNA组,差异具有统计学意义(P0.05);膨胀钉组患者躁动率为10.00%低于PFNA组患者躁动率为33.33%,具有统计学意义(P0.05)。结论:可膨胀髓内钉具有手术时间较短、出血量少,更利于骨折的愈合,且躁动发生率较低,对股骨转子间骨折的疗效优于较近端螺旋刀片抗旋髓内钉,对临床有指导意义,值得临床推广。     

PFN与DHS治疗老年不稳定型股骨粗隆下骨折的疗效分析

目的:比较PFN与DHS内固定治疗老年不稳定型股骨粗隆下骨折的预后及评其疗效方法:2002年1月至2008年1月我科共收治老年不稳定型股骨粗隆下骨折患者129例,男59例,女70例,年龄51～86岁,平均61.7岁随机选择PFN或DHS内固定,PFN组62例,DHS组67例。比较两组的手术时间、术中出血量、术后第二天CRP值、张力侧出现骨痂时间、骨折愈合时间、Harris评分等6项指标。结果:116例获得13～48个月的随访,平均18.7月,除手术时间及Harris评分无差异外,PFN组在术中出血量、术后第二天CRP值、张力侧出现骨痂时间、骨折平均愈合时间等方面与DHS组比较有显著优势(P<0.05)结论:PFN内固定创伤小、术后并发症率较低,可以成为治疗老年不稳定型股骨粗隆下骨折的主要方法     

PFN与DHS治疗老年不稳定型股骨粗隆下骨折的疗效分析

目的：比较PFN与DHS内固定治疗老年不稳定型股骨粗隆下骨折的预后及评其疗效。方法：2002年1月至2008年1月我科共收治老年不稳定型股骨粗隆下骨折患者129例,男59例,女70例,年龄51～86岁,平均61．7岁。随机选择PFN或DHS内固定,PFN组62例,DHS组67例。比较两组的手术时间、术中出血量、术后第二天CRP值、张力侧出现骨痂时间、骨折愈合时间、Harris评分等6项指标。结果：116例获得13-48个月的随访,平均18．7月,除手术时间及Harris评分无差异外,PFN组在术中出血量、术后第二天CRP值、张力侧出现骨痂时间、骨折平均愈合时间等方面与DHS组比较有显著优势（P〈0．05）。结论：PFN内固定创伤小、术后并发症率较低,可以成为治疗老年不稳定型股骨粗隆下骨折的主要方法。     

动力加压髋螺钉对股骨上段生物力学特征性的影响

目的：探讨股骨上端骨折,以动力加压髋螺钉进行骨固定治疗,骨折愈合后,取出动力加压髋螺钉以后的股骨上段与完整的股骨上段的生物力学特性相比较,为临床内固定取出术后功能锻炼的强度提供量化依据。方法：收集8具新鲜尸体股骨标本进行实验应力分析,分别测定完整股骨上段和动力加压髋螺钉取出后股骨上段的力学特性改变。结果：动力加压髋螺钉取出术后股骨上段的力学特性与完整股骨上段的力学特性相比有显著的差异（P＜0．01）。结论：股骨上端骨折如果以动力加压髋螺钉为治疗手段,在骨折愈合取出内固定后,功能锻炼只能控制在慢速步行水平,不能进行奔跑、跳跃等活动,以防止再骨折等并发症的发生。     

Prediction of strength and strain of the proximal femur by a CT-based finite element method

Hip fractures are the most serious complication of osteoporosis and have been recognized as a major public health problem. In elderly persons, hip fractures occur as a result of increased fragility of the proximal femur due to osteoporosis. It is essential to precisely quantify the strength of the proximal femur in order to estimate the fracture risk and plan preventive interventions. CT-based finite element analysis could possibly achieve precise assessment of the strength of the proximal femur. The purpose of this study was to create a simulation model that could accurately predict the strength and surface strains of the proximal femur using a CT-based finite element method and to verify the accuracy of our model by load testing using fresh frozen cadaver specimens. Eleven right femora were collected. The axial CT scans of the proximal femora were obtained with a calibration phantom, from which the 3D finite element models were constructed. Materially nonlinear finite element analyses were performed. The yield and fracture loads were calculated, while the sites where elements failed and the distributions of the principal strains were determined. The strain gauges were attached to the proximal femoral surfaces. A quasi-static compression test of each femur was conducted. The yield loads, fracture loads and principal strains of the prediction significantly correlated with those measured (r=0.941, 0.979, 0.963). Finite element analysis showed that the solid elements and shell elements in undergoing compressive failure were at the same subcapital region as the experimental fracture site.     

Densitometric, morphometric and mechanical distributions in the human proximal femur

With the prevalent use of DXA-measured BMD to assess pathologic hip fractures and its recently reported lack of reliability to predict fracture or account for efficacy of anti-resorptive therapy, it is reasonable to assess whether variations in the primary and secondary tensile and compressive trabecular microstructure can account for variations in proximal femur strength in comparison to DXA-measured BMD. To that end, microstructural and densitometric measures of trabecular bone specimens, from discrete sites within the proximal femur, were correlated with their mechanical properties. We hypothesize that accounting for regional variations in trabecular microstructure will improve predictions of proximal femur strength and stiffness compared to bone density measured by DXA. Forty-seven samples (seven donors) from seven distinct sites of human proximal femur underwent DXA and muCT imaging and mechanical testing. The results revealed significant variations in BMC, morphometric indices and mechanical properties within the proximal femur. This work has demonstrated that the mechanical performance of each sub-region is highly dependent on the corresponding trabecular microstructure. BMD measured by DXA at standard regions of interest cannot resolve the variations in trabecular density and microstructure that govern the mechanical behavior of the proximal femur. This work suggests that a quantitative Singh index that uses high resolution QCT to monitor the trabecular microstructure at specific sub-regions of the proximal femur may allow better predictions of hip fracture risk in individual patients and an improved assessment of changing bone structure in response to pharmacological interventions.     

The Odocoileus virginianus Femur: Mechanical Behavior and Morphology

Biomechanical research relies heavily on laboratory evaluation and testing with osseous animal structures. While many femora models are currently in use, including those of the European red deer (Cervus elaphus), the Odocoileus virginianus femur remains undocumented, despite its regional abundance in North America. The objective of this study was to compare biomechanical and morphological properties of the Odocoileus virginianus femur with those of the human and commonly used animal models. Sixteen pairs of fresh-frozen cervine femora (10 male, 6 female, aged 2.1 ± 0.9 years) were used for this study. Axial and torsional stiffnesses (whole bone) were calculated following compression and torsion to failure tests (at rates of 0.1 mm/sec and 0.2°/sec). Lengths, angles, femoral head diameter and position, periosteal and endosteal diaphyseal dimensions, and condylar dimensions were measured. The results show that the cervine femur is closer in length, axial and torsional stiffness, torsional strength, and overall morphology to the human femur than many other commonly used animal femora models; additional morphological measurements are comparable to many other species’ femora. The distal bicondylar width of 59.3mm suggests that cervine femora may be excellent models for use in total knee replacement simulations. Furthermore, the cervine femoral head is more ovoid than other commonly-used models for hip research, making it a more suitable model for studies of hip implants. Thus, with further, more application-specific investigations, the cervine femur could be a suitable model for biomechanical research, including the study of ballistic injuries and orthopaedic device development.     

Development of a locking femur nail for mice

We herein report on a novel locking intramedullary nail system in a murine closed femur fracture model. The nail system consists of a modified 24-gauge injection needle and a 0.1-mm-diameter tungsten guide wire. Rotation stability was accomplished by flattening the proximal and distal end of the needle. Torsional mechanical testing of the implants in osteotomized cadaveric femora revealed a superiority of the locking nail (3.9+/-1.0 degrees rotation at a torque of 0.9 Nmm, n=10) compared to the unmodified injection needle (conventional nail; 52.4+/-3.2 degrees, n=10, p<0.05). None of the implants, however, achieved the rotation stability of unfractured femora (0.3+/-0.5 degrees, n=10). In a second step, we tested the feasibility of the in vivo application of the locking nail to stabilize a closed femoral midshaft fracture in C57BL/6 mice. Of interest, none of the 10 animals showed a dislocation of the locking nail over a 5-week period, while 3 of 4 animals with conventional nail fracture stabilization showed a significant pin dislocation within the first 3 days (p<0.05). Mechanical testing after 5-weeks stabilization with the locking nail revealed an appropriate bone healing with a torque at failure of 71.6+/-3.4% and a peak rotation before failure of 68.4+/-5.3% relative to the unfractured contralateral femur. With the advantage that closed fractures can be fixed with rotation stability, the herein introduced model may represent an ideal tool to study bone healing in transgenic and knockout mice.     

半髋关节置换治疗高龄老年人不稳定转子间骨折的效果研究

目的:探讨半髋关节置换术治疗老年不稳定性转子间骨折的治疗效果。方法:选择我院骨科2013年1月至2015年2月入院的老年不稳定转子间骨折患者64例,随机分为半髋关节置换组和髓内钉固定组,对两组手术时间、术中出血量、术后并发症、术后髋关节功能恢复状况进行评价。结果:半髋关节置换组手术时间较髓内钉固定组短(P0.05),半髋关节置换组和髓内钉固定组术中出血量、手术后并发症、髋关节功能恢复状况的差异不具有统计学意义(P0.05)。结论:半髋关节置换术治疗老年不稳定性转子间骨折具有较好的临床效果。     

逆行可膨胀髓内钉与锁定钢板治疗股骨远端骨折的疗效比较

目的:探讨比较运用逆行可膨胀髓内钉与股骨远端锁定钢板治疗股骨远端33A、33C1型骨折的疗效。方法:对2013年3月至2015年6月收治并符合纳入标准的43例股骨远端33A、33C1型骨折患者进行回顾性研究。按照不同的手术固定方式分为逆行可膨胀髓内钉组(n=18)和锁定钢板组(n=25),记录并比较两组手术时间、失血量、愈合时间及功能结果、术中及术后并发症。结果:所有骨折最终都获得愈合;逆行可膨胀髓内钉组在手术时间及失血量上都显著低于锁定钢板组,两组在愈合时间及功能评定方面无明显差异;5例开放性骨折的患者中1例出现浅表伤口感染,1例患者延迟愈合。结论:股骨远端逆行可膨胀髓内钉在获得与锁定钢板相当的骨折愈合时间及患肢功能的情况下,具有操作简单、手术时间短、失血量少等特点,对于股骨远端33A、33C1型骨折来说是一个较好的选择。     

微创经皮LCP 接骨术治疗老年股骨近端粉碎骨折

目的:本研究通过观察微创锁定钢板接骨术治疗老年股骨近端粉碎骨折临床效果,旨在找出最佳治疗方式。方法:自2007年12月～2010年03月,应用股骨近端锁定加压钢板治疗老年股骨近端粉碎骨折23例。记录术中出血量、手术时间,术后并发症、骨折愈合时间及最后一次随访时功能恢复情况。结果:骨折临床愈合时间为12～28周,平均16周。除1例患者髋内翻畸形,1例锁定加压钢板断裂外,其他患者均达到骨性愈合。结论:股骨近端锁定钢板具有创伤小、固定可靠、骨折愈合快、功能恢复满意的特点,尤其适用于老年股骨近端粉碎骨折。     

股骨近端三维有限元模型评价髋部骨折患者骨密度

目的：探究骨密度与老年髋部骨折股骨近端三维有限元模型密度的关系。方法：选取8 例老年髋部骨折,其中4 例股骨颈骨 折,4 例股骨转子间骨折;左侧肢体3 例,右侧肢体5 例。分别测定腰椎骨密度和双侧髋关节CT 资料,运用Mimics软件和abaqus 软件对健侧股骨近端进行重建和计算出该模型的密度。结果：股骨转子间骨折组腰椎骨密度为(-4.05± 0.24) g/cm2,三维有限元模 型密度为[(1.15± 0.02)× 106],均低于股骨颈骨折组的(-3.15± 0.54) g/cm2,[(1.34± 0.06)× 106],两组比较差异均有统计学意义（均 P<0.05）。腰椎的骨密度与三维有限元模型密度成线性正相关（r=0.881,P=0.004）。结论：骨密度与老年髋部骨折股骨近端三维有限 元模型密度成线性正相关的关系,可为进一步用有限元分析法探讨老年髋部骨折部位与骨密度的关系提供理论依据。     

锁定型gamma钉与普通型gamma钉、动力髋螺钉治疗不稳定性股骨粗隆间骨折的 临床疗效比较

目的:比较锁定型γ钉(Locking Gamma Nail,LGN)、普通型γ钉(Traditional Gamma Nail,TGN)和动力髋螺钉(Dynamic Hip Screw,DHS)治疗不稳定性股骨粗隆间骨折的临床疗效和安全性。方法:选择2009年1月至2011年1月在我院分别接受锁定型γ钉(A组)、普通型γ钉(B组)和动力髋(C组)内固定治疗的随访资料完整的患者共92例。记录和比较三组患者的手术时间、术中出血量、骨折愈合时间及末次髋关节功能评分等相关数据。结果:A组、B组和C组的手术时间、术中出血比较有统计学差异(均P<0.01),但A、B组之间无明显统计学差异;A组和B组、C组的骨折愈合时间、髋关节功能评分比较差异均有统计学意义(均P<0.01),B、C组之间无明显统计学意义。结论:LGN的固定效果和生物力学性能良好,操作简便,固定牢固,整体治疗效果优于TGN和DHS,可作为临床治疗不稳定性股骨粗隆间骨折的首选。     

SL-R柄人工股骨头置换术与股骨近端防旋髓内钉治疗老年不稳定型骨质疏松性股骨粗隆间骨折的疗效比较研究

目的:探讨股骨近端防旋髓内钉、SL-R柄人工股骨头置换术两种术式治疗老年不稳定型骨质疏松性股骨粗隆间骨折的应用效果。方法:选取2015年1月-2017年6月间于河北医科大学附属秦皇岛市第一医院行手术治疗的老年不稳定型骨质疏松性股骨粗隆间骨折患者98例,以数表法将患者随机均分为对照组(n=49)和观察组(n=49)。其中对照组采用股骨近端防旋髓内钉,观察组采用SL-R柄人工股骨头置换术。比较两组患者临床各项指标、手术前后髋关节功能评分以及术后并发症发生情况。结果:观察组手术时间、术中失血量均高于对照组,但住院时间、开始负重时间则低于对照组(P0.05)。观察组术后并发症发生率为4.08%(2/49),低于对照组的18.37%(9/49)(P0.05)。术后1个月、3个月时患者髋关节各项评分相比术前均有升高,术后3个月的各项评分高于术后1个月(P0.05);观察组术后1个月、3个月各项评分均高于对照组(P0.05)。结论:在老年不稳定型骨质疏松性股骨粗隆间骨折患者治疗过程当中,采用SL-R柄人工股骨头置换术可减少住院时间,疗效确切,无严重并发症,且可改善髋关节各项功能评分。     

Biomechanical and clinical alterations of the hip joint following femoral neck fracture and implantation of bipolar hip endoprosthesis

The implantation of a bipolar partial hip endoprosthesis is a treatment of choice for displaced medial femoral neck fracture. We present an experimental study which asses and compare biomechanical and clinical status through period before and after hip fracture and implantation of bipolar partial hip endoprosthesis. This study encompassed 75 patients who suffered from an acute medial femoral neck fracture and were treated with the implantation of a bipolar partial hip endoprosthesis. Their biomechanical status (stress distribution on the hip joint weight bearing area) and clinical status (Harris Hip Score) were estimated for the time prior to the injury and assessed at the follow-up examination that was, on average, carried out 40 months after the operation. Despite ageing, the observed Harris Hip Score at the follow-up examination was higher than that estimated prior to the injury (77.9 > 69.6; p = 0.006). Similarly, the hip stress distribution was reduced (2.7 MPa < 2.3 MPa; p = 0.001). While this reduction can be attributed to a loss of weight due to late ageing, the principal improvement came from the operative treatment and corresponding restoration of the biomechanical properties of the hip joint. The implantation of a bipolar partial hip endoprosthesis for patients with displaced medial femoral neck fractures improves the biomechanical and clinical features of the hip, what should have on mind during making decision about treatment.     

Variation of trabecular architecture in proximal femur of postmenopausal women

This investigation of microstructure in the human proximal femur probes the relationship between the parameters of the FRAX index of fracture risk and the parameters of bone microstructure. The specificity of fracture sites at the proximal femur raises the question of whether trabecular parameters are site-specific during post-menopause, before occurrence of fragility fracture. The donated proximal femurs of sixteen post-menopausal women in the sixth and seventh decades of life, free of metabolic pathologies and therapeutic interventions that could have altered the bone tissue, constituted the material of the study. We assessed bone mineral density of the proximal femurs by dual energy X-ray absorptiometry and then sectioned the femurs through the center of the femoral head and along the femoral neck axis. For each proximal femur, morphometry of trabeculae was conducted on the plane of the section divided into conventional regions and sub-regions consistent with the previously identified trabecular families that provide regions of relatively homogeneous microstructure. Mean trabecular width and percent bone area were calculated at such sites. Our findings indicate that each of mean trabecular width and percent bone area vary within each proximal femur independently from each other, with dependence on site. Both trabecular parameters show significant differences between pairs of sites. We speculate that a high FRAX index at the hip corresponds to a reduced percent bone area among sites that gives a more homogeneous and less site-specific quality to the proximal femur. This phenomenon may render the local tissue less able to carry out the expected mechanical function.     

Distal skeletal tibia assessed by HR-pQCT is highly correlated with femoral and lumbar vertebra failure loads

Dual energy X-ray absorptiometry (DXA) is the standard for assessing fragility fracture risk using areal bone mineral density (aBMD), but only explains 60–70% of the variation in bone strength. High-resolution peripheral quantitative computed tomography (HR-pQCT) provides 3D-measures of bone microarchitecture and volumetric bone mineral density (vBMD), but only at the wrist and ankle. Finite element (FE) models can estimate bone strength with 86–95% precision. The purpose of this study is to determine how well vBMD and FE bone strength at the wrist and ankle relate to fracture strength at the hip and spine, and to compare these relationships with DXA measured directly at those axial sites. Cadaveric samples (radius, tibia, femur and L4 vertebra) were compared within the same body. The radius and tibia specimens were assessed using HR-pQCT to determine vBMD and FE failure load. aBMD from DXA was measured at the femur and L4 vertebra. The femur and L4 vertebra specimens were biomechanically tested to determine failure load. aBMD measures of the axial skeletal sites strongly correlated with the biomechanical strength for the L4 vertebra (r = 0.77) and proximal femur (r = 0.89). The radius correlated significantly with biomechanical strength of the L4 vertebra for vBMD (r = 0.85) and FE-derived strength (r = 0.72), but not with femur strength. vBMD at the tibia correlated significantly with femoral biomechanical strength (r = 0.74) and FE-estimated strength (r = 0.83), and vertebral biomechanical strength for vBMD (r = 0.97) and FE-estimated strength (r = 0.91). The higher correlations at the tibia compared to radius are likely due to the tibia’s weight-bearing function.     

Concept and development of an orthotropic FE model of the proximal femur

PURPOSE: In contrast to many isotropic finite-element (FE) models of the femur in literature, it was the object of our study to develop an orthotropic FE "model femur" to realistically simulate three-dimensional bone remodelling. METHODS: The three-dimensional geometry of the proximal femur was reconstructed by CT scans of a pair of cadaveric femurs at equal distances of 2mm. These three-dimensional CT models were implemented into an FE simulation tool. Well-known "density-determined" bony material properties (Young's modulus; Poisson's ratio; ultimate strength in pressure, tension and torsion; shear modulus) were assigned to each FE of the same "CT-density-characterized" volumetric group.In order to fix the principal directions of stiffness in FE areas with the same "density characterization", the cadaveric femurs were cut in 2mm slices in frontal (left femur) and sagittal plane (right femur). Each femoral slice was scanned into a computer-based image processing system. On these images, the principal directions of stiffness of cancellous and cortical bone were determined manually using the orientation of the trabecular structures and the Haversian system. Finally, these geometric data were matched with the "CT-density characterized" three-dimensional femur model. In addition, the time and density-dependent adaptive behaviour of bone remodelling was taken into account by implementation of Carter's criterion. RESULTS: In the constructed "model femur", each FE is characterized by the principal directions of the stiffness and the "CT-density-determined" material properties of cortical and cancellous bone. Thus, on the basis of anatomic data a three-dimensional FE simulation reference model of the proximal femur was realized considering orthotropic conditions of bone behaviour. CONCLUSIONS: With the orthotropic "model femur", the fundamental basis has been formed to realize realistic simulations of the dynamical processes of bone remodelling under different loading conditions or operative procedures (osteotomies, total hip replacements, etc).     

Stress changes in the femoral head due to porous ingrowth surface replacement arthroplasty

Finite element stress analyses were conducted of the canine femoral head before and after implantation of various surface replacement-type components. The femoral head was replaced by four implant geometries; (a) shell, (b) shell with peg, (c) shell with rod, and (d) a new epiphyseal replacement design. All implants were modelled to simulate bony ingrowth along the underside of the shell and along the surfaces of the peg and rod. The results indicated that in the normal femur the forces are transferred from the articular surface through the femoral head cancellous bone to the inferior cortical shell of the femoral neck. After shell-type surface replacement, forces were transferred more distally at the rim of the shell and at the end of the peg or rod, thereby reducing the stresses in the proximal head cancellous bone. Computer simulation of bone remodelling due to proximal bone stress reduction was shown to accentuate the abnormality of the stress fields. Surface replacement with a lower modulus material created a less abnormal redistribution of bone stresses. The new epiphyseal replacement design resulted in stress distributions similar to those in the normal femoral head and minimal shear stresses at the implant/bone interface. These findings suggest that the epiphyseal replacement concept may provide better initial mechanical integrity and create a more benign milieu for adaptive bone remodelling than conventional, shell-type surface replacement components.