三种不同内固定法治疗髌骨骨折82 例临床疗效的分析

目的:观察三种不同内固定法治疗髌骨骨折82例临床疗效及安全性。方法:将82例髌骨骨折患者随机分成三组,其中30人接受双克氏针钢丝环绕法治疗,髌骨周缘环形缝扎处理21例,31人应用镍钛聚髌器治疗。从手术时间、优良率、愈合时间、手术费用及并发症等指标进行评价。结果:三种内固定方法治疗髌骨骨折组的手术时间差异无统计学意义(P>0.05),镍钛聚髌器组的愈合时间、手术费用及术后并发症与双克氏针钢丝环绕法组及髌骨周缘环形缝扎处理组相比,差异具有统计学意义(P<0.05);镍钛聚髌器治疗髌骨粉碎性骨折的优良率与其它两组相比,差异具有统计学意义(P<0.05);三种方法治疗髌骨横断性骨折的优良率相互比较差异无统计学意义。结论:双克氏针钢丝环绕法、髌骨周缘环形缝扎法及镍钛聚髌器法都可以被采纳治疗髌骨横断性骨折;在治疗髌骨粉碎性骨折优先采用镍钛聚髌器法。     

天鹅记忆接骨器治疗骨折与骨不连动态记忆生物力学电测分析

目的：为临床使用天鹅记忆接骨器（SMC）提供科学的依据,并为进一步研究SMC动态记忆生物力学行为肱骨内部应力场奠定基础。方法：通过贴片,标定,得到SMC的载荷－应变曲线,然后根据SMC固定新鲜人体肱骨的应变值,计算SMC的动态记忆持骨力值。结果：SMC的鹅颈加压部,鹅体接骨板部,鹅翼持骨部三部相互协调,记忆持骨,其动态记忆持骨的生物学力值为110．35N,结论：SMC具有良好的耐疲劳重复使用性,其产生的动态记忆持骨力为术后早期功能锻炼提供了保证。     

三种不同内固定法治疗锁骨骨折62 例临床疗效的分析

目的:观察三种不同内固定法治疗锁骨骨折临床疗效及安全性.方法:将62例锁骨骨折患者随机分成三组,其中15人接受双克氏针钢丝环绕法治疗,钢板螺钉内固定处理17例,30人应用镍钛记忆合金环抱器治疗.从手术时间、优良率、愈合时间、术中出血及并发症等指标进行评价.结果:三种内固定方法治疗锁骨骨折组的手术时间、愈合时间、术中出血差异无统计学意义(P＞0.05),镍钛记忆合金环抱器组的术后并发症与双克氏针钢丝环绕法组及钢板螺钉内固定处理组相比,有差异具有统计学意义(P＜0.05);镍钛记忆合金环抱器治疗锁骨骨折的优良率与其它两组相比,有差异具有统计学意义(P＜0.05).结论:镍钛记忆合金环抱器法治疗锁骨骨折的临床疗效优于双克氏针钢丝环绕法、钢板螺钉内固定法.     

后交叉韧带断裂对外侧半月板生物力学的影响

目的:探讨后交叉韧带(Posterior cruciate ligament,PCL)损伤后对外侧半月板各部位生物力学特性的影响,为PCL断裂后外侧半月板损伤的防治避免骨性关节炎提供力学理论依据.方法:自愿捐献新鲜成年男性正常膝关节标本共10具,年龄21～36岁,平均32.3岁,为非对称性,左、右膝关节各5具.置于自制运动夹具上并通过电子试验机连续轴向加载0～800N负荷模拟膝关节的受力,采用压力感受器分别测定PCL完整组及PCL断裂组外侧半月板前角体部和后角于屈膝0、30、60及90°时应变值.结果:膝关节0°位,在PCL完整时,前角、体部和后角的应变均为负值,为压应变,当PCL完全切断时,前角、体部应变在各种载荷下较完整时均出现负向减小,而后角的应变却出现负向增大.膝关节30°、60°、90°位,PCL完整时前角、体部的应变为正值,是拉应变,且随载荷和角度的增大而增大,后角的应变是负值,为压应变,且随载荷和角度的增大而负向增大,PCL断裂组应变值明显大于完整组.不同角度不同载荷下两组差异均有统计学意义(P＜0.05).结论:PCL断裂会对外侧半月板产生显著的生物力学影响,这也为伤后避免膝关节屈曲负重和早期重建PCL保护半月板功能避免骨性关节炎提供了力学理论依据.     

镍钛形状记忆合金环抱器内固定术对多发性肋骨骨折患者术后疼痛、呼吸功能及肺部感染的影响

目的:探讨多发性肋骨骨折患者采用镍钛形状记忆合金环抱器内固定术治疗的临床效果。方法:选取2016年1月-2018年1月期间我院收治的97例多发性肋骨骨折患者。按照不同的治疗方法将患者分为对照组(n=47)和研究组(n=50),对照组患者给予胸部护板外固定术,研究组患者给予镍钛形状记忆合金环抱器内固定术。比较两组患者术后7 d的临床疗效,比较两组术前、术后7 d疼痛程度及呼吸功能情况,记录两组术后并发症发生情况。结果:研究组患者治疗后总有效率为92.00%(46/50),高于对照组患者的76.60%(36/47)(P0.05)。两组患者术后7 d视觉疼痛模拟评分量表(VAS)评分均较术前降低,且研究组低于对照组(P0.05)。两组患者术后7 d最大自主通气量占预计值百分比(MVV%)较术前升高,且研究组高于对照组(P0.05);两组患者术后7 d第1秒用力呼气肺活量占预计值百分比(FEV1%)比较无差异(P0.05)。研究组患者术后并发症总发生率8.00%(4/50),低于对照组的23.40%(11/47)(P0.05)。结论:多发性肋骨骨折经镍钛形状记忆合金环抱器内固定术治疗安全、有效,可明显减轻患者术后疼痛及改善呼吸功能,临床应用价值较高。     

氟对镍钛拉簧的腐蚀性研究

目的:研究模拟应用氟化物防龋的口腔环境下,不同浓度氟化物对镍钛拉簧的应力衰减的影响。方法:选取两种国内常用品牌0.010 inch镍钛拉簧各40根,随机将每种拉簧平均分入四个浓度组(0.05%、0.10%、0.15%和对照组),将相同浓度组的不同品牌弹簧分别固定于间距为20 mm的四个支架的两端。将四个支架分别放入37℃人工唾液中水浴。将实验组按浓度分组放入不同浓度氟化人工唾液(0.05%、0.10%、0.15%)中处理5 min,每天三次。分别于实验前、实验后1周、2周、3周、4周用拉伸机测量每根弹簧拉伸至20 mm时的应力。对实验结果使用重复测量的方差分析。结果:时间因素对两种镍钛拉簧拉伸应力的衰减的影响有统计学意义,氟化物浓度有辅助效应,二者有交互作用。氟化物作用下不同品牌镍钛拉簧的应力腐蚀变化不同。(P0.05)。结论:1.氟化物的存在可以增加镍钛拉簧的应力衰减。2.在正畸治疗的临床工作中在使用氟化物时应考虑增加镍钛拉簧的更换频率。     

高应变率下牛股骨粘弹性性质的研究

采用SHPB装置对湿润牛股骨在高应变率（10^1-10^31/秒）下的非线性粘弹性力学行为进行实验观测，为比较起见，也作了应变率为ε=0.7×10^-41/秒的准静态单轴压缩实验和ε=1.63×10^-21/秒的恒应变率单轴压缩实验，从而从实验上得到了（0.7×10^-4-10^31/秒）应变率范围内牛股骨中应力σ、应变ε和应变率ε之间的关系。运用Green和Rivlin非线性粘弹性的多重积分本构关系理论对实验结果进行解释，提出牛股骨的本构议程：σ（t)=E0ε αε^2 βτ^3 E1∫^t0ε(τexp(-t-τdτ E2∫^t0ε(τexp(-t-τ/^2)dε лэ。     

影响sc镍钛器械分离的相关因素分析

摘要 目的：分析影响sc镍钛器械分离的相关因素。方法：收集2020年1月至2022年4月在本院接受根管治疗的病例的离体牙。据研究目的和内容设计一般调查表收集临床资料。采用Schneider法测定根管弯曲度。结果：本次研究共收集到10047例病例,涉及22306个根管。其中236例病例（247根镍钛器械）发生器械分离,分离率为2.35%。其中有205例镍钛器械分离发生在磨牙,分离率为4.29%。有106例镍钛器械分离发生在上颌,分离率为1.83%;有130例镍钛器械分离发生在下颌,分离率为3.06%,两者相比差异具有统计学意义（x²=77.128,P<0.001）。轻度弯曲组镍钛器械分离率为0.32%,中度弯曲组镍钛器械分离率为1.04%,重度弯曲组镍钛器械分离组为3.46%,极重度弯曲组镍钛器械分离率为5.82%;随着根管弯曲度的增加,镍钛器械分离率呈明显上升趋势（z=291.883,P<0.001）。结论：sc镍钛器械分离率为2.35%,下颌磨牙根管预备中,器械分离发生率最高,根管弯曲度对器械分离发生也具有一定影响。     

应变稳态：稳态理论的完善

应变稳态（Allostasis）是基于稳态（Homestasis）的新兴生态学概念,它强调机体能在外界变化的环境中维持内环境稳定。综述了应变稳态的概念及其与稳态的区别与联系．进而阐述了不同类型的应变稳态状态（allostatic state）的生理功能和应变稳态负荷（allostatic load）的原理与类型。     

大鼠离体心肌粘性劲度定量评定的研究

本实验依据心肌工作模型和心肌顺应性的理论,从大鼠离体心肌静态、动态应力-应变指数曲线和应力松弛对数曲线中,求得反映心肌粘性劲度的指标η_1和η_2,并对心肌组织粘性成分的粘性劲度进行了定量评定。η_1和η_2值与心肌粘性劲度呈同向性变化、且重复性好。本工作提示,η_1和η_2可作为实用可靠的定量评定心肌顺应性的指标。     

Procedure for Investigating the Patellar Reflex under Isometric Conditions

A procedure for investigating the patellar reflex is described for isometric conditions when the position of the shin relative to the thigh is rigidly fixed by a special device. The sensors of the device record the development of the moment of force in each knee joint separately. The results obtained with an electromyogram and a mechanogram are compared.     

Patellar taping increases vastus medialis oblique activity in the presence of patellofemoral pain.

A common rehabilitation strategy for patellofemoral pain syndrome (PFPS), which lacks scientific evidence, includes pulling the patella medially with tape to reduce pain and increase the vastus medialis oblique (VMO) muscle activity. The purpose of this study was to examine the effect of various patellar taping procedures on force production, EMG activity of the VMO and vastus lateralis (VL) muscles, and perceived pain experienced by 30 women (27.3 +/- 1.53), half diagnosed with PFPS. The perceived pain, force, and EMG of the VMO and VL, were recorded while subjects performed maximal isokinetic leg presses at 30 degrees /s for each of the following patellar taping conditions: no tape (control), no glide (placebo), medial and lateral glide (experimental). The medial and placebo procedures significantly (P < 0.01) reduced perceived pain (70-80%) in PFPS subjects. Although patellar taping did not influence leg press force (P > 0.05), it increased the VMO activity and decreased the VL activity in PFPS subjects but had the opposite effect in healthy subjects. The findings suggest that taping the patella medially can contribute positively to PFPS rehabilitation. Because the medial glide and placebo taping conditions had similar effects, it is proposed that the benefits of patellar taping are not due to a change in patellar position but rather due to enhanced support of the patellofemoral ligaments and/or pain modulation via cutaneous stimulation.     

张力带钢丝法治疗髌韧带断裂

目的:探讨张力带钢丝法治疗髌韧带断裂的疗效。方法:回顾分析13例髌韧带断裂的手术治疗情况。结果:1例于术后2月出现钢丝断裂,但韧带连续性和强度恢复良好。其它所有病例功能恢复均达伤前水平,无韧带再断裂。结论:采用张力带钢丝法,以及对合并髌韧带挛缩或者缺损病例,结合半腱肌肌腱重建修复髌韧带断裂效果良好。     

Patellar cartilage deformation in vivo after static versus dynamic loading

The objective of this study was to test the hypothesis that static loading (squatting at a 90 degrees angle) and dynamic loading (30 deep knee bends) cause different extents and patterns of patellar cartilage deformation in vivo. The two activities were selected because they imply different types of joint loading and reflect a realistic and appropriate range of strenuous activity. Twelve healthy volunteers were examined and the volume and thickness of the patellar cartilage determined before and from 90 to 320s after loading, using a water excitation gradient echo MR sequence and a three-dimensional (3D) distance transformation algorithm. Following knee bends, we observed a residual reduction of the patellar cartilage volume (-5.9+/-2.1%; p<0.01) and of the maximal cartilage thickness (-2.8+/-2.6%), the maximal deformation occurring in the superior lateral and the medial patellar facet. Following squatting, the change of patellar cartilage volume was -4.7+/-1.6% (p<0.01) and that of the maximal cartilage thickness -4.9+/-1.4% (p<0.01), the maximal deformation being recorded in the central aspect of the lateral patellar facet. The volume changes were significantly lower after squatting than after knee bends (p<0.05), but the maximal thickness changes higher (p<0.05). The results obtained in this study can serve to validate computer models of joint load transfer, to guide experiments on the mechanical regulation of chondrocyte biosynthesis, and to estimate the magnitude of deformation to be encountered by tissue-engineered cartilage within its target environment.     

Forces acting on the patella during maximal voluntary contraction of the quadriceps femoris muscle at different knee flexion/extension angles

From knee extension moments measured with a dynamometer, the quadriceps muscle force, the patellar ligament force and the reaction force in the patellofemoral joint at various knee angles (0-90 degrees) were estimated. The information needed to calculate the combined effect of both patellofemoral and tibiofemoral joint on the mechanical advantage of the muscle was obtained from lateral-view radiographs of autopsy knees. The results show that the smallest quadriceps force (2,000 N) is exerted at maximal extension, and the largest force (8,000 N) at about 75 degrees of flexion. The patellar ligament force reaches a maximum (5,000 N) at 60 degrees. The reaction force in the patellofemoral joint is the smallest (1,000 N) at extension and is of the same values as the muscle force in a range from 75 to 90 degrees. Especially at large flexion angles, the value of the estimated forces is considerably larger (by 100%) than reported in the literature. This difference is attributed to the influence of the patellofemoral joint on the mechanical advantage of the muscle, which has not been taken into account in other studies.     

Influence of Age on Patellar Tendon Reflex Response

Background

A clinical parameter commonly used to assess the neurological status of an individual is the tendon reflex response. However, the clinical method of evaluation often leads to subjective conclusions that may differ between examiners. Moreover, attempts to quantify the reflex response, especially in older age groups, have produced inconsistent results. This study aims to examine the influence of age on the magnitude of the patellar tendon reflex response.

Methodology/Principal Findings

This study was conducted using the motion analysis technique with the reflex responses measured in terms of knee angles. Forty healthy subjects were selected and categorized into three different age groups. Patellar reflexes were elicited from both the left and right patellar tendons of each subject at three different tapping angles and using the Jendrassik maneuver. The findings suggested that age has a significant effect on the magnitude of the reflex response. An angle of 45° may be the ideal tapping angle at which the reflex can be elicited to detect age-related differences in reflex response. The reflex responses were also not influenced by gender and were observed to be fairly symmetrical.

Conclusions/Significance

Neurologically normal individuals will experience an age-dependent decline in patellar reflex response.     

Patellar mechanics during simulated kneeling in the natural and implanted knee

Kneeling is required during daily living for many patients after total knee replacement (TKR), yet many patients have reported that they cannot kneel due to pain, or avoid kneeling due to discomfort, which critically impacts quality of life and perceived success of the TKR procedure. The objective of this study was to evaluate the effect of component design on patellofemoral (PF) mechanics during a kneeling activity. A computational model to predict natural and implanted PF kinematics and bone strains after kneeling was developed and kinematics were validated with experimental cadaveric studies. PF joint kinematics and patellar bone strains were compared for implants with dome, medialized dome, and anatomic components. Due to the less conforming nature of the designs, change in sagittal plane tilt as a result of kneeling at 90° knee flexion was approximately twice as large for the medialized-dome and dome implants as the natural case or anatomic implant, which may result in additional stretching of the quadriceps. All implanted cases resulted in substantial increases in bone strains compared with the natural knee, but increased strains in different regions. The anatomic patella demonstrated increased strains inferiorly, while the dome and medialized dome showed increases centrally. An understanding of the effect of implant design on patellar mechanics during kneeling may ultimately provide guidance to component designs that reduces the likelihood of knee pain and patellar fracture during kneeling.     

Patellar reflex: II. Associated activation

Skeletal muscle activation accompanying voluntary (or involuntary) constriction of a local group of muscles and the use of the Jendrassik maneuver has been studied. Voluntary contraction of hand muscles, e.g., by squeezing a hand dynamometer, is the most convenient method for inducing the associated activation of skeletal muscles, thereby reinforcing the patellar reflex. Here, this method is also conventionally called the Jendrassik maneuver. In addition, the effects of sound and light on the patellar reflex have been studied.     

两种内固定方法治疗髌骨骨折术后关节面对合情况的比较

目的：比较改良张力带钢丝内固定和传统张力带钢丝内固定治疗髌骨横行骨折术后关节面对合的效果。方法：2007年3月至2011年9月,分别采用胥氏张力带钢丝内固定和改良张力带钢丝内固定且随访超过1年的髌骨横行骨折的患者64例,术中分别采用胥氏张力带钢丝内固定和改良张力带钢丝内固定治疗,随访时行膝关节X线摄片检查,观察关节面对合情况,比较两种治疗方法所致关节面台阶样错位是否大于2mm的差异。结果：64例患者均获得随访,随访时间8~18个月,平均13.2个月,骨折端均愈合,两组Lysholm评分比较无统计学意义（P=0.665）;胥氏张力带钢丝内固定组和改良张力带钢丝内固定组分贝出现1例（3.1%）和7例（21.9%）关节面台阶征,两组关节面台阶征的发生率比较差异有统计学意义（P=0.036）。结论：胥氏张力带钢丝固定法使髌骨骨折术后固定作用加强,关节面对合更好,能有效预防因台阶征引起的创伤性关节炎的发生。     

Lateral force–displacement behaviour of the human patella and its variation with knee flexion — a biomechanical study in vitro

This study measured the patellar lateral force–displacement behaviour at a range of knee flexion angles in normal human cadaver specimens. The knee extensor muscles were loaded in proportion to their physiological cross-sectional areas, the tensions being applied in physiological directions along the separate quadriceps muscles. Knee extension was blocked at a range of knee flexion angles from 0 to 90°, and patellar lateral displacement versus force characteristics were measured. This experiment was repeated with three total muscle forces, 20, 175 and 350 N, which were held constant at all flexion angles. It was shown that similar stability variation was obtained with the different total muscle loads, and also the forces required to produce a range of patellar displacements (1, 5, 9 mm) were examined. A 5 mm lateral patellar displacement required a constant displacing force (i.e. the patella had constant lateral stability) up to 60° knee flexion, and then a significant increase at 90°. The results were related to surgicaland anatomical observations.