膝骨关节炎患者本体感觉、肌力及关节功能的相关性研究

目的 通过研究膝骨关节炎患者的膝关节本体感觉、屈伸肌群峰力矩及膝关节功能,探索三者之间的相关性。方法 本研究共纳入56例膝骨关节炎患者。本体感觉评估和膝关节屈伸肌群肌力评估均采用Isomed 2000等速肌力测试训练仪。个体本体感觉功能以膝关节的被动运动感知阈为评价指标,膝关节屈伸肌群肌力以膝关节屈伸肌群的峰力矩及峰力矩体质量比为评价指标。膝关节功能评估采用WOMAC问卷量表。同时对上述三者的相关性进行分析。再以膝骨关节炎患者关节功能WOMAC评分为因变量,年龄、体质量指数、 VAS疼痛评分、双侧Kellgren-Lawrance分级均值、双侧股四头肌肌力均值、双侧腘绳肌肌力均值、双侧本体感觉误差均值作为自变量进行多元逐步回归分析。结果 膝关节左、右侧本体感觉与股四头肌肌力及腘绳肌肌力均存在负相关（ Pr=0.659, Pr分别为－0.511、－0.408, PB）=0.385, P=0.007〕、VAS疼痛评分（B=0.347, P=0.014）与WOMAC评分呈正相关。结论 膝骨关节炎患者本体感觉-被动运动感知阈的低下与关节屈伸肌群肌力下降及关节功能下降有关。膝骨关节炎患者疼痛程度、本体感觉功能一定程度上参与影响膝骨关节炎患者的关节功能。     

舌体对舌力介导器的静息压力分析

目的:探讨坐位静息状态下舌肌对不同矢状向和垂直向位置舌力介导器的压力,以初步探索舌力介导器作为一种支抗方式的效用范围. 方法:纳入19例个别正常牙合志愿者(男4名,女15名,年龄23~33岁) ,分别个体化制作舌力介导器,矢状向测量选取正中线上对应于第二前磨牙远中、第一磨牙远中和第二磨牙远中3个部位,垂直向测量以舌位记录为参考零点,分别测量-3 mm、0 mm和3 mm这3个高度对应于第一磨牙远中处的压力. 所用传感器型号为美国Honeywell公司生产的FSS1500NS,压力校验仪、监测仪以及分析软件由厦门福芯微电子科技有限公司设计制作. 志愿者取坐位,测量舌体处于自然放松状态时的静息压力. 使用Friedman test对矢状向及垂直向各组数据进行多样本比较的秩和检验,P<0. 05为差异有统计学意义. 结果:在垂直向上,随着舌力介导器高度增加,压力逐渐增大(P<0. 001),-3 mm、0 mm和3 mm高度的压力均值分别为105. 83 Pa、167. 75 Pa和254. 25 Pa. 在矢状向上,压力由近中至远中逐渐减小(P<0. 001),其均值分别为177. 64 Pa、126. 72 Pa和109. 37 Pa. 结论:舌肌在静息状态下对舌力介导器的压力随基托高度增加而增大,并且由近中至远中逐渐减小,但在实际应用时应综合考虑效果和舒适度,不宜过高和偏远中.     

股骨近端防旋髓内钉手术治疗对老年股骨粗隆间骨折患者骨代谢和骨强度的影响

目的 探讨股骨近端防旋髓内钉手术(PFNA)治疗对老年股骨粗隆间骨折患者骨代谢和骨强度的影响.方法 选择2014年1月至2015年8月医院收治的老年股骨粗隆间骨折患者50例为观察组对象,另在医院健康体检处选择50例无骨折病史的正常老年人作为对照组,对观察组患者进行PFNA治疗,测定并比较手术前后观察组患者和对照组正常老年人的骨代谢和骨强度指标.结果 手术前,观察组患者骨代谢指标中前胶原氨基末端前肽Ⅰ型(PINP)、甲状旁腺激素(PTH)、Ⅰ型胶原羧基端肽(CTX)和血清骨钙素(OC)水平均明显高于对照组(均P<0.05),而25(OH)D3明显低于对照组(P<0.05);手术后,观察组患者血清PINP水平[(86.03±27.78)mg/L]较手术前[(53.97±26.13)mg/L]明显升高(P<0.05);PTH水平[(27.67±11.54)ng/L]较手术前[(51.22±17.65)ng/L]明显下降(P<0.05),略高于对照组[(36.85±12.86)ng/L](P>0.05),25(OH)D3、CTX和OC水平与手术前比较无明显变化(均P>0.05).手术前,观察组患者股骨粗隆间区以及股骨颈区骨强度指标中横截面转动贯量(CSMI)、骨密度(BMD)和截面模量z值(Z)均比对照组低(均P<0.05),屈曲比率(BR)明显高于对照组(P<0.05);手术后,观察组患者骨强度指标与手术前相比均稍有下降,但不具有统计学意义(P>0.05).结论 老年股骨粗隆间骨折患者经PFNA治疗后骨代谢增加,骨强度无明显改变,可能由于手术中应力遮挡作用而使髓内钉周围骨有少量丢失,需要加强抗骨质疏松治疗和防护措施以预防骨折.     

用骨强度概念探索骨密度测量的诊断指标

30多年来，医学上一直用骨矿密度（BMD,g/cm^2）诊断骨质疏松，骨质疏松引起骨折，骨折由骨强度减低引起，体重是骨强度的重要决定因素。 本引入体重评价BMC（g）和BMD两个指标。结果，体重与BMC的相关明显强于与BMD的相关，证明男女之间的BMC差由体重引起，男女间相同体重配对的BMC没有差异，所以在评价骨的 力学强度上体重标准化后BMC优于BMC指标。     

Improving Risk Assessment: Hip Geometry, Bone Mineral Distribution and Bone Strength in Hip Fracture Cases and Controls. The EPOS Study

Hip geometry and bone mineral density (BMD) have previously been shown to relate independently to hip fracture risk. Our objective was to determine by how much hip geometric data improved the identification of hip fracture. Lunar pencil beam scans of the proximal femur were obtained. Geometric and densitometric values from 800 female controls aged 60 years or more (from population samples which were participants in the European Prospective Osteoporosis Study, EPOS) were compared with data from 68 female hip fracture patients aged over 60 years who were scanned within 4 weeks of a contralateral hip fracture. We used Lunar DPX ‘beta’ versions of hip strength analysis (HSA) and hip axis length (HAL) applied to DPX(L) data. Compressive stress (Cstress), calculated by the HSA software to occur as a result of a typical fall on the greater trochanter, HAL, body mass index (BMI: weight/(height)²) and age were considered alongside femoral neck BMD (FN-BMD, g/cm²) as potential predictors of fracture. Logistic regression was used to generate predictors of fracture initially from FN-BMD. Next age, Cstress (as the most discriminating HSA-derived parameter), HAL and BMI were added to the model as potentially independent predictors. It was not necessary to include both HAL and Cstress in the logistic models, so the entire data set was examined without excluding the subjects missing HAL measurements. Cstress combined with age and BMI provided significantly better prediction of fracture than FN-BMD used alone as is current practice, judged by comparing areas under receiver operating characteristic (ROC) curves (p<0.001, deLong’s test). At a specificity of 80%, sensitivity in identification was improved from 66% to 81%. Identifying women at high risk of hip fracture is thus likely to be substantially enhanced by combining bone density with age, simple anthropometry and data on the structural geometry of the hip. HSA might prove to be a valuable enhancement of DXA densitometry in clinical practice and its use could justify a more pro-active approach to identifying women at high risk of hip fracture in the community. Received: 16 March 2001 / Accepted: 3 August 2001     

The association between isoinertial trunk muscle performance and low back pain in male adolescents

The literature reports inconsistent findings regarding the association between low back pain (LBP) and trunk muscle function, in both adults and children. The strength of the relationship appears to be influenced by how LBP is qualified and the means by which muscle function is measured. The aim of this study was to examine the association between isoinertial trunk muscle performance and consequential (non-trivial) low back pain (LBP) in male adolescents. Healthy male adolescents underwent anthropometric measurements, clinical evaluation, and tests of trunk range of motion (ROM), maximum isometric strength (STRENGTH) and peak movement velocity (VEL), using an isoinertial device. They provided information about their regular sporting activities, history and family history of LBP. Predictors of “relevant/consequential LBP” were examined using multivariable logistic regression. LBP status was reassessed after 2 years and the change from baseline was categorised. At baseline, 33/95 (35%) subjects reported having experienced consequential LBP. BMI, a family history of LBP, and regularly playing sport were each significantly associated with a history of consequential LBP (p < 0.05). 85/95 (89%) boys participated in the follow-up: 51 (60%) reported no LBP at either baseline or follow-up (never LBP); 5 (6%) no LBP at baseline, but LBP at follow-up (new LBP); 19 (22%) LBP at baseline, but none at follow-up; and 10 (12%) LBP at both time-points (recurrent/persistent LBP). The only distinguishing features of group membership in these small groups were: fewer sport-active in the “never LBP” group); worse trunk mobility, in the “persistent LBP” group, lower baseline sagittal ROM in the “never LBP” and “new LBP” (p < 0.05). Regular involvement in sport was a consistent predictor of LBP. Isoinertial trunk performance was not associated with LBP in adolescents.     

胸主动脉夹层动脉瘤假腔壁力学分析的动物实验

目的从力学的角度分析腹主动脉瘤破裂和胸主动脉夹层动脉瘤破裂的原因。方法通过胸主动脉夹层假腔内外层的屈服形状改变比能,发现两者间的关系。结果60%的实验犬形成夹层模型。假腔内层的形状改变比能测试结果差异有统计学意义。结论当胸主动脉管壁遭遇大于内层屈服形状改变比能而又小于外层屈服形状改变比能的血流冲击时,就会导致中膜分离形成夹层。     

Pullout strength of anterior spinal instrumentation: a product comparison of seven screws in calf vertebral bodies

A lot of new implant devices for spine surgery are coming onto the market, in which vertebral screws play a fundamental role. The new screws developed for surgery of spine deformities have to be compared to established systems. A biomechanical in vitro study was designed to assess the bone–screw interface fixation strength of seven different screws used for correction of scoliosis in spine surgery. The objectives of the current study were twofold: (1) to evaluate the initial strength at the bone–screw interface of newly developed vertebral screws (Universal Spine System II) compared to established systems (product comparison) and (2) to evaluate the influence of screw design, screw diameter, screw length and bone mineral density on pullout strength. Fifty-six calf vertebral bodies were instrumented with seven different screws (USS II anterior 8.0 mm, USS II posterior 6.2 mm, KASS 6.25 mm, USS II anterior 6.2 mm, USS II posterior 5.2 mm, USS 6.0 mm, USS 5.0 mm). Bone mineral density (BMD) was determined by quantitative computed tomography (QCT). Failure in axial pullout was tested using a displacement-controlled universal test machine. USS II anterior 8.0 mm showed higher pullout strength than all other screws. The difference constituted a tendency (P = 0.108) when compared to USS II posterior 6.2 mm (+19%) and was significant in comparison to the other screws (+30 to +55%, P < 0.002). USS II posterior 6.2 mm showed significantly higher pullout strength than USS 5.0 mm (+30%, P = 0.014). The other screws did not differ significantly in pullout strength. Pullout strength correlated significantly with BMD (P = 0.0015) and vertebral body width/screw length (P < 0.001). The newly developed screws for spine surgery (USS II) show higher pullout strength when compared to established systems. Screw design had no significant influence on pullout force in vertebral body screws, but outer diameter of the screw, screw length and BMD are good predictors of pullout resistance.     

Influence of internal fixator flexibility on murine fracture healing as characterized by mechanical testing and microCT imaging

Mechanically well‐defined stabilization systems have only recently become available, providing standardized conditions for studying the role of the mechanical environment on mouse bone fracture healing. The aim of this study was to characterize the time course of strength recovery and callus development of mouse femoral osteotomies stabilized with either low or high flexibility (in bending and torsion) internal fixation plates. Animals were euthanized and femora excised at 14, 21, and 28 days post‐osteotomy for microCT analysis and torsional strength testing. While a larger mineralized callus was observed in osteotomies under more flexible conditions at all time points, the earlier bridging of the mineralized callus under less flexible conditions by 1 week resulted in an earlier recovery of torsional strength in mice stabilized with low flexibility fixation. Ultimate torque values for these bones were significantly higher at 14 and 21 days post‐osteotomy compared to bones with the more flexible stabilization. Our study confirms the high reproducibility of the results that are achieved with this new implant system, therefore making it ideal for studying the influence of the mechanical environment on murine fracture healing under highly standardized conditions. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29: 1245–1250, 2011     

Comparison of two platelet activation markers using flow cytometry after in vitro shear stress exposure of whole human blood

Platelet activation is the initiating step to thromboembolic complications in blood‐contacting medical devices. Currently, there are no widely accepted testing protocols or relevant metrics to assess platelet activation during the in vitro evaluation of new medical devices. In this article, two commonly used platelet activation marker antibodies, CD62P (platelet surface P‐selectin) and PAC1 (activated GP IIb/IIIa), were evaluated using flow cytometry. Anticoagulant citrate dextrose solution A (ACDA) and heparin anticoagulated human blood from healthy donors were separately exposed to shear stresses of 0, 10, 15, and 20 Pa for 120 s using a cone‐plate rheometer model, and immediately mixed with the platelet marker antibodies for analysis. To monitor for changes in platelet reactivity between donors and over time, blood samples were also evaluated after exposure to 0, 2, and 20 µM of adenosine diphosphate (ADP). Following ADP stimulation, the percentage of both CD62P and PAC1 positive platelets increased in a dose dependent fashion, even 8 h after the blood was collected. After shear stress stimulation, both CD62P and PAC1 positive platelets increased significantly at shear stress levels of 15 and 20 Pa when ACDA was used as the anticoagulant. However, for heparinized blood, the PAC1 positive platelets decreased with increasing shear stress, while the CD62P positive platelets increased. Besides the anticoagulant effect, the platelet staining buffer also impacted PAC1 response, but had little effect on CD62P positive platelets. These data suggest that CD62P is a more reliable marker compared with PAC1 for measuring shear‐dependent platelet activation and it has the potential for use during in vitro medical device testing.