Fracture toughness of steel-fiber-reinforced bone cement

Fractures in the bone-cement mantle (polymethyl methacrylate) have been linked to the failure of cemented total joint prostheses. The heat generated by the curing bone cement has also been implicated in the necrosis of surrounding bone tissue, leading to loosening of the implants. The addition of reinforcements may improve the fracture properties of bone cement and decrease the peak temperatures during curing. This study investigates the changes in the fracture properties and the temperatures generated in the ASTM F451 tests by the addition of 316L stainless steel fibers to bone cement. The influence of filler volume fraction (5-15% by volume) and aspect ratios (19, 46, 57) on the fracture toughness of the acrylic bone cement was assessed. Increasing the volume fraction of the steel fibers resulted in significant increases in the fracture toughness of the steel-fiber-reinforced composite. Fracture-toughness increases of up to 2.63 times the control values were obtained with the use of steel-fiber reinforcements. No clear trend in the fracture toughness was discerned for increasing aspect ratios of the reinforcements. There is a decrease in the peak temperatures reached during the curing of the steel-fiber-reinforced bone cement, though the decrease is too small to be clinically relevant. Large increases in the fatigue life of acrylic bone cement were also obtained by the addition of steel fibers. These results indicate that the use of steel fibers may enhance the durability of cemented joint prostheses.     

重建钉治疗股骨颈干骨折

目的探讨重建型交锁髓内钉在股骨复杂骨折中的应用。方法10例创伤性股骨颈干骨折重建型交锁髓内钉固定。结果10例获得随访10～43个月，平均25个月。1例骨感染经处理后骨延迟愈合，未出现交锁钉断裂及股骨头坏死等并发症，本组优5例，良4例，可1例，优良率为90％。结论同侧股骨颈合并股骨干的复杂股骨骨折，选择重建型交锁髓内钉固定较为合适。本方法创伤小、并发症少，固定牢固，可早期功能锻炼，功能恢复良好。     

合并同侧股骨干骨折的股骨颈骨折5例漏诊分析

目的:分析合并同侧股骨干骨折的股骨颈骨折的漏诊原因及治疗方法.方法:5例合并同侧股骨干骨折的股骨颈骨折患者均在漏诊情况下行股骨干骨折切开复位、内固定术;确定诊断后,1例改行重建髓内钉内固定,1例改行DHS内固定,1例行全髋置换,另2例未予处理.结果:2例改换内固定术式者骨折愈合,髋关节功能优;2例未行处理者骨折畸形愈合,髋关节功能差;1例行全髋置换者功能为良.结论:漏诊与原发损伤重,体检不全面,X线投照不规范,阅片不仔细等因素有关.一旦漏诊,手术治疗效果优于非手术治疗.     

骨密度对股骨颈骨折内固定效果影响的生物力学研究

目的:为提高股骨颈骨折内固定治疗的效果,通过生物力学实验,观察骨密度对内固定强度的影响。方法:取成人股骨上段防腐标本２０只,测量股骨颈骨密度值。根据骨密度值高低,将标本分为Ａ、Ｂ两组,每组１０只。两组的骨密度值有显著差异(Ｐ＜０．０１)。将标本制成股骨颈骨折模型,均用加压螺纹钉内固定后行负载实验,比较两组固定的强度。结果:骨密度低的Ｂ组标本在４００Ｎ载荷下的骨折位移明显大于骨密度高的Ａ组(Ｐ＜０．０１),且最大负荷也明显小于Ａ组(Ｐ＜０．０１)。结论:骨密度对股骨颈骨折固定的强度有直接影响,骨密度值可作为预测股骨颈骨折内固定治疗效果的一个重要指标。     

利用股骨重建钉治疗同侧股骨颈股骨干骨折临床分析

目的探讨应用股骨重建钉治疗同侧股骨干、股骨颈骨折的临床疗效。方法对28例同侧股骨干股骨颈骨折患者采用股骨重建钉治疗。结果术后随访12～45个月,股骨干骨折临床愈合时间为25～35周,平均28周;股骨颈骨折临床愈合时间为12～30周,平均18周。结论应用股骨重建钉治疗同侧股骨干、股骨颈骨折可获得良好的临床疗效,具有一定的应用价值。     

Fracture toughness of bovine bone: influence of orientation and storage media

Using the single-edge notched bending (SENB) test, two fracture toughness parameters of longitudinal and transverse bovine bone specimens were evaluated: the critical stress intensity factor, Kc, determined from the peak load to initiate fracture, and the energy or work of fracture, Wf, the energy required to extend a crack through a notched specimen. It was found that preservation of bone in alcohol resulted in a 25-45% higher Kc value compared to control specimens stored in physiological saline; whereas the work of fracture, Wf, demonstrated the opposite behaviour, with the alcohol stored specimens having a 28-56% lower value than the saline control specimens. It was established that the effect of alcohol is reversible upon the bone being restored in saline. Consistent with previous studies, it was found that cracks oriented in the longitudinal direction resulted in both a significantly lower fracture toughness and lower work of fracture than those cracks directed transversely. The results are discussed in terms of the proposed deformation and fracture mechanisms known to occur in bone.     

In vitro biomechanical study of femoral torsion disorders: effect on tibial proximal epiphyseal cancellous bone deformation

Purpose  

Osteoarthritis (OA) of the knee is a degenerative disease mainly found in elderly population. Valgus deformity seems to be directly related to lateralised gonarthrosis. Contradictory outcomes of surgical series are published in the literature and report satisfactory and unsatisfactory long-term results. Lower limb torsions disorders have been considered as being another factor inducing gonarthrosis. This paper presents an in vitro study aiming at quantifying the relationships between experimental femoral torsion disorders (medial and lateral) and the deformation of the cancellous bone of the proximal tibial epiphysis (CB_TPE).     

Exploration on the effect of predeposit autotransfusion on bone marrow hematopoiesis after femoral shaft fracture

ObjectiveBy observing the changes in the number and activity of CD34+ cells in bone marrow after predeposit autotransfusion (PAT) to patients with femoral shaft fracture (FSF), to evaluate the effects of PAT on hematopoietic function and hematopoietic stem cells in bone marrow.MethodsSelected FSF patients were randomly divided into 2 groups: the control group (patients did not receive blood transfusion after surgery) and PAT group (patients received PAT after surgery). The content of RBC and Plt in blood samples were counted by blood routine. The cell cycle and proportion of CD34+ myelinated cells in blood samples was analyzed by flow cytometry. The telomere DNA length of hematopoietic stem cells (HSCs) in the control groups and PAT group at postoperation 24 was analyzed by southern blot.ResultsThe content of RBC and Plt in postoperation 6 h and 24 h in the control group was evidently higher compared to that in PAT group, while Hb content in control group was significantly lower compared to that in PAT group. The proportion of CD34+ myelinated cells in post-transfusion 6 h and postoperation 24 h in PAT group was evidently higher compared to that in the control group. In PAT group, S phase at postoperation 24 h was significantly larger compared to that at post-transfusion 6 h. The telomere DNA length of HSCs in PAT group was longer than that in the control group.ConclusionPAT can increase the number of HSC, while does not cause the abnormal aging of HSCs. PAT is suitable for postoperative blood transfusion of patients with FSF.     

股骨和胫骨骨干骨折内固定术前测量评估髓内钉长度的研究进展

目的:总结股骨和胫骨骨干骨折内固定术前髓内钉长度测量评估方法的研究进展,为临床应用提供参考。方法:以"股骨""胫骨""髓内钉长度""术前测量"以及"femur""tibia""intramedullary length""preoperative measurement"等为中、英文关键词,在中国知网、万方医学、Pub...     

Histomorphometric and osteocytic characteristics of cortical bone in male subtrochanteric femoral shaft

The histomorphometric properties of the subtrochanteric femoral region have rarely been investigated. The aim of this study was to investigate the age‐associated variations and regional differences of histomorphometric and osteocytic properties in the cortical bone of the subtrochanteric femoral shaft, and the association between osteocytic and histological cortical bone parameters. Undecalcified histological sections of the subtrochanteric femoral shaft were obtained from cadavers (n = 20, aged 18–82 years, males). They were cut and stained using modified Masson‐Goldner stain. Histomorphometric parameters of cortical bone were analysed with ×50 and ×100 magnification after identifying cortical bone boundaries using our previously validated method. Within cortical bone areas, only complete osteons with typical concentric lamellae and cement line were selected and measured. Osteocytic parameters of cortical bone were analyzed under phase contrast microscopy and epifluorescence within microscopic fields (0.55 mm² for each). The cortical widths of the medial and lateral quadrants were significantly higher than other quadrants (P < 0.01). Osteonal area per cortical bone area was lower and cortical porosities were higher in the posterior quadrant than in the other quadrants (P < 0.05). Osteocyte lacunar number per cortical bone area was found higher in the young subjects (≤ 50 years) than in the older ones (> 50 years) both before and after adjustments for body height and weight (P < 0.05). Moreover, significant but low correlations were found between the cortical bone and osteocytic parameters (0.20 ≤ R² ≤ 0.35, P < 0.05). It can be concluded that in healthy males, the cortical histomorphometric parameters differ between the anatomical regions of the subtrochanteric femoral shaft, and are correlated with the osteocytic parameters from the same site. These findings may be of use when discussing mechanisms that predispose patients to decreasing bone strength.     

皮持骨在拉伸型,剪切型和撕裂型加载条件下的断裂韧性——纵向断裂…

对以质骨在拉伸、剪切和撕裂型载荷下的裂纹启裂韧性进行了研究。总数为１３０个紧凑拉式样,紧凑剪切试样和三腿型试样分别用于测量骨的拉伸型、剪切型和撕裂型启裂韧性。多试样柔度法用来测定当ａ／Ｗ＝０．５５（１,裂纹长度,Ｗ,试样宽度）时的临界能量释放率。临界应力强度因子由ａ／Ｗ＝０．５５的试样在试验中得到的临界载荷来计算。为了考察骨力学 各是性对于它的剪切型和撕裂裂纹启裂韧性的影响,对骨试样的裂纹扩展方向     

Changes in bone architecture in the femoral head and neck in osteoarthritis

This study analyses changes in the bony architecture of the femoral head and neck in osteoarthritis. Five osteoarthritic hips were obtained from female patients undergoing total hip replacement and were compared to non-arthritic control specimens from the dissecting room. Analysis was carried out on a coronal bony slice of the femoral head and on a transverse section of the upper femoral neck. The results indicated that in the region of the compressive trabeculae the intertrabecular areas were generally smaller in the osteoarthritic specimens and that the inferior part of the cortex of the femoral neck had thickened. Our data thus quantified changes consistent with the thickening of compressive trabeculae reported by others and with thickening of the region of the femoral neck on which they converge. We found less trabecular bone in non-weight-bearing regions of the lower femoral head and in the medulla of the upper neck in the osteoarthritic specimens consistent with loss of tensile trabeculae. Scanning electron microscopy suggested that bone resorption activity was higher in the subchondral and non-weight-bearing regions of the osteoarthritic femoral heads than in the controls.     

Differences and relationships between the physical properties and the microscopic structure of human femoral,tibial and fibular cortical bone

Coefficients of correlation between certain physical properties and the histological components of the break area were calculated on an IBM 7090 computer for 56 femoral, 79 tibial and 37 fibular specimens of embalmed cortical bone of standardized size and shape. Strong positive correlations (0.01–0.02 significance level) were found between tensile strength and the percentage of interstitial lamellae in the break area; between hardness and the number of osteons/mm²; and between hardness and the percentage of osteons in the break area. Equally high negative correlations were found between tensile strength and percentage of osteons in the break area; between shearing strength and average area/osteon remnant; between elastic modulus and percentage of spaces in the break area; and an even higher correlation (0.001) between hardness and percentage of spaces in the break area. Negative correlations (at slightly more than 0.05 significance level) were found between shearing strength and modulus and average area/osteon. Osteons tend to reduce the tensile strength and elastic modulus of bone while interstitial lamellae tend to increase them. The probable reason is the relatively greater amount of cement lines, which are sites of weakness where failure can occur, in Haversian bone as compared with lamellar bone. The predominant orientation of collagen fibers and the amount and distribution of calcium may also be involved. These factors are now being investigated.     

股骨颈支持带的解剖学研究及临床意义

目的　探讨股骨颈支持带的形态结构特点,为临床股骨颈的安全显露提供解剖学依据。 方法　取新鲜下肢标本4例、红色乳胶灌注固定标本60例,通过显微解剖、铸型标本和股骨颈支持带切片等方法研究股骨颈支持带的位置、形态、分布及中段宽度等。 结果　(1)3条支持带的形态结构特点：上支持带出现率100%,恒定出现,走行在11:00～13:00位置,此支持带变异最小;下支持带出现率为100%,走行在06:00～07:30位置,在3条支持带中它最为坚韧;前支持带出现率为60%,变异最大,走行在02:30～04:00位置。(2) 组织切片显微镜观察发现血管贯穿于支持带,上、下支持带均有血管、神经支配。(3) 股骨颈安全显露的区域：08：00～10：00的位置,此处支持带较少出现。 结论　上、下支持带恒定出现,走行位置较为恒定,且富含血管、神经,是股骨头血供的重要来源,同时经大转子后内侧切开显露股骨颈,操作更安全、方便。     

Maximal voluntary isokinetic knee flexion torque is associated with femoral shaft bone strength indices in knee replacement patients

It is currently unknown whether knee replacement-associated bone loss is modified by rehabilitation programs. Thus, a sample of 45 (18 men and 25 women) persons with unilateral knee replacement were recruited; age 66 years (sd 6), height 169 cm (sd 8), body mass 83 kg (sd 15), time since operation 10 months (sd 4) to explore the associations between maximal torque/power in knee extension/flexion and femoral mid-shaft bone traits (Cortical cross-sectional area (CoA, mm(2)), cortical volumetric bone mineral density (CoD, mg/mm(3)) and bone bending strength index (SSI, mm(3))). Bone traits were calculated from a single computed tomography slice from the femoral mid-shaft. Pain in the operated knee was assessed with the WOMAC questionnaire. Stepwise regression models were built for the operated leg bone traits, with knee extension and flexion torque and power, age, height, body mass, pain score and time since operation as independent variables. CoA was 2.3% (P=0.015), CoD 1.2% (P<0.001) and SSI 1.6% (P=0.235) lower in the operated compared to non-operated leg. The overall proportions of the variation explained by the regression models were 50%, 29% and 55% for CoA, CoD and SSI, respectively. Body mass explained 12% of Coa, 11% of CoD and 11% of SSI (P≤0.003). Maximal knee flexion torque explained 38% of Coa, 7% of CoD and 44% of SSI (p≤0.047). For CoD time since operation also became a significant predictor (11%, P=0.045). Knee flexion torque of the operated leg was positively associated with bone strength in the operated leg. Thus, successful rehabilitation may diminish bone loss in the operated leg.     

三参数模型计算股骨颈松质骨压缩蠕变方程

背景：无论是人工关节的研究还是股骨颈骨折内外固定都需要了解股骨颈松质骨的蠕变力学特性。 目的：通过实验定量得出股骨颈蠕变与时间的变化规律。 方法：在电子万能试验机上对股骨颈松质骨8个试样进行蠕变实验。模拟人体体温36.5 ℃的温度场下进行实验,蠕变实验的应力增加速度为0.11 MPa/s。设定实验时间为7 200 s,采集100个数据以三参数模型处理实验数据。 结果与结论：股骨颈松质骨蠕变,最初600 s变化较快,之后应变缓慢上升,7 200 s蠕变量为0.84%。结果显示蠕变曲线是以指数关系变化的,三参数模型能很好的拟合股骨颈松质骨的蠕变曲线和方程。     

激素性股骨头坏死与股骨颈骨折患者股骨头内骨小梁形态学对比研究

目的利用微计算机断层扫描技术(Micro-CT)对比分析激素性股骨头坏死与股骨颈骨折患者的股骨头内骨小梁的结构特点。 方法选取2016年9月至2017年9月因股骨颈骨折与激素性股骨头坏死于大连大学附属中山医院行人工全髋关节置换术的患者,分别设为骨折组与坏死组,每组各20例(20髋),术中完整取出股骨头作为研究材料。应用计算机对股骨头进行三维重建,利用x、y、z轴各2个相互平行的平面将股骨头分割成27个区域,27个区域的编号规则：分为内侧、中间、外侧3个区,每组按照由前向后、由上向下的顺序编为1～9号。内侧区编号为m1、m2……m9;中间区编号为c1、c2……c9;外侧区编号为l1、l2……l9。对样本进行Micro-CT断层扫描,获取股骨头样本的计算机三维图像。手工选取兴趣区,采用骨体积分数、骨小梁厚度、骨小梁数量、骨小梁间隙等三维空间参数分别对2组股骨头内骨小梁进行评价。数据比较采用t检验和单因素方差分析。 结果在骨折组中,将股骨头按矢状面分割为内侧区、中间区、外侧区进行对比,中间区表现为骨体积分数均值最大、厚度均值最大、数量均值最大、间隙均值最小的优势骨小梁区域,差异均有统计学意义(F＝36.59、73.50、38.60、48.50,P值均小于0.05);将股骨头按冠状面分割为前区、中间区、后区进行对比,前区表现为骨体积分数均值最大、厚度均值最大、数量均值最大、间隙均值最小,差异均有统计学意义(F＝69.50、43.92、85.40、36.00,P值均小于0.05);将股骨头按水平面分割为上区、中间区、下区进行对比,上区表现为骨体积分数均值最大、厚度均值最大、数量均值最大、间隙均值最小,差异均有统计学意义(F＝37.03、29.47、255.50、45.50,P值均小于0.05)。对比坏死组股骨头不同部位骨小梁微结构参数,如果将股骨头分为内侧区、中间区、外侧区,中间区表现为骨体积分数均值最大、厚度均值最大、数量均值最大、间隙均值最小的优势骨小梁区域,差异均有统计学意义(F＝41.42、26.60、400.00、36.00,P值均小于0.05);如果将股骨头分为上区、中间区、下区,上区表现为骨体积分数均值最大、厚度均值最大、数量均值最大、间隙均值最小,差异均有统计学意义(F＝52.99、25.33、28.50、37.33,P值均小于0.05);如果将股骨头分为前区、中间区、后区,前区表现为骨体积分数均值最大、厚度均值最大、数量均值最大、间隙均值最小,差异均有统计学意义(F＝2 567.17、57.29、42.11、41.17,P值均小于0.05)。与坏死组相比,骨折组骨小梁骨体积分数均值更大,差异有统计学意义(t＝4.90,P＝0.01)、骨小梁厚度均值更大,差异有统计学意义(t＝－4.17,P＝0.01)、骨小梁数量均值更大,差异有统计学意义(t＝－31.37,P＝0.01),骨小梁间隙均值更小,差异有统计学意义(t＝－7.12,P＝0.01)。 结论激素对于坏死股骨头的影响不仅仅是坏死区,包括硬化区、正常骨小梁区,即对于整个股骨头都产生了影响。     

生物型与骨水泥型人工股骨头置换治疗高龄股骨颈骨折

背景：随着人工关节材料、工艺及技术的成熟和发展,人工股骨头置换治疗股骨颈骨折尤其是老年患者有移位的股骨颈骨折日渐普及。 目的：观察生物型与骨水泥型人工股骨头置换治疗合并心脏病老年性股骨颈骨折的临床疗效。 方法：选择2004年1月至2009年12月天津疗养院骨科中心收治合并心脏病的股骨颈骨折患者35例,其中合并心绞痛型冠心病16例,心肌梗死型冠心病8例,无症状冠心病8例,缺血性心肌病冠心病3例。18例采用生物型人工股骨头置换,17例采用骨水泥型人工股骨头置换。 结果与结论：35例患者除1例在术中死亡外,34例均获得随访,随访时间8-36个月,置换过程中出现3例并发症均为骨水泥型组,其中1例在手术过程中经抢救无效死亡,2例在置换过程中血压下降,呼吸困难,经过抢救后生命特征恢复正常。在随访过程中发现生物型组中2例骨质疏松较严重的患者有部分假体下沉,生物型组优良率89%(16/18),骨水泥型组优良率94%(16/17),提示对于合并严重心脏病的患者适合运用生物型人工股骨头置换,而有骨质疏松的患者适合运用骨水泥型人工股骨头置换。