EFFECTS OF SEAT POSITION ON THE JOINT MOMENTS OF THE LOWER EXTREMITIES DURING CYCLING IN THE ELDERLY

The purpose of this study was to quantify the joint moments of the lower extremities with different seat positions during cycling in elderly. Fifteen older adults performed cycling on a self-developed bicycle ergometer at three horizontal and three vertical seat positions. The pedals were instrumented with six-component load cells to measure pedal reaction forces; and a motion capture system was used to measure body segment kinematic data. Both data sets were used to calculate joint moments during a crank cycle. The results showed that seat positions affected joint moments significantly, especially the horizontal positions. A more posterior seat position led to a more balanced loading at the hip and knee, with less peak muscle loadings. The results will be helpful for cycle design and fitting for the elderly

Pulmonary Tuberculosis with Delayed Tuberculosis Infection of Total Knee Arthroplasty

Tuberculous prosthetic joint infection is rare. While early diagnosis is critical for treatment, it is usually delayed. Here, we present the case of a 72-year-old patient who underwent total knee arthroplasty for his right knee due to degenerative arthritis 4 years ago. Three years after arthroplasty, pulmonary tuberculosis was found and he hesitated on starting antituberculosis chemotherapy. He suffered from progressive pain and swelling of the right prosthetic knee for 2 months before this admission. The pathologic report of the debridement of the right prosthetic knee was caseous granulomatous inflammation with positive acid-fast staining bacilli. The culture of the debridement also yielded Mycobacterium tuberculosis. He died due to aspiration pneumonia with multiorgan dysfunction. This case is a reminder of the possibility of tuberculosis while dealing with prosthetic joint infection. [J Formos Med Assoc 2007;106(1):82-85

Comparison and prediction of pullout strength of conical and cylindrical pedicle screws within synthetic bone

<p>Abstract</p> <p>Background</p> <p>This study was designed to derive the theoretical formulae to predict the pullout strength of pedicle screws with an inconstant outer and/or inner diameter distribution (conical screws). For the transpedicular fixation, one of the failure modes is the screw loosening from the vertebral bone. Hence, various kinds of pedicle screws have been evaluated to measure the pullout strength using synthetic and cadaveric bone as specimens. In the literature, the Chapman's formula has been widely proposed to predict the pullout strength of screws with constant outer and inner diameters (cylindrical screws).</p> <p>Methods</p> <p>This study formulated the pullout strength of the conical and cylindrical screws as the functions of material, screw, and surgery factors. The predicted pullout strength of each screw was compared to the experimentally measured data. Synthetic bones were used to standardize the material properties of the specimen and provide observation of the loosening mechanism of the bone/screw construct.</p> <p>Results</p> <p>The predicted data from the new formulae were better correlated with the mean pullout strength of both the cylindrical and conical screws within an average error of 5.0% and <it>R</it>²= 0.93. On the other hand, the average error and <it>R</it>²value of the literature formula were as high as -32.3% and -0.26, respectively.</p> <p>Conclusion</p> <p>The pullout strength of the pedicle screws was the functions of bone strength, screw design, and pilot hole. The close correlation between the measured and predicted pullout strength validated the value of the new formulae, so as avoid repeating experimental tests.</p

18F-FDG PET/CT-based gross tumor volume definition for radiotherapy in head and neck Cancer: a correlation study between suitable uptake value threshold and tumor parameters

<p>Abstract</p> <p>Background</p> <p>To define a suitable threshold setting for gross tumor volume (GTV) when using ¹⁸Fluoro-deoxyglucose positron emission tomography and computed tomogram (PET/CT) for radiotherapy planning in head and neck cancer (HNC).</p> <p>Methods</p> <p>Fifteen HNC patients prospectively received PET/CT simulation for their radiation treatment planning. Biological target volume (BTV) was derived from PET/CT-based GTV of the primary tumor. The BTVs were defined as the isodensity volumes when adjusting different percentage of the maximal standardized uptake value (SUVmax), excluding any artifact from surrounding normal tissues. CT-based primary GTV (C-pGTV) that had been previously defined by radiation oncologists was compared with the BTV. Suitable threshold level (sTL) could be determined when BTV value and its morphology using a certain threshold level was observed to be the best fitness of the C-pGTV. Suitable standardized uptake value (sSUV) was calculated as the sTL multiplied by the SUVmax.</p> <p>Results</p> <p>Our result demonstrated no single sTL or sSUV method could achieve an optimized volumetric match with the C-pGTV. The sTL was 13% to 27% (mean, 19%), whereas the sSUV was 1.64 to 3.98 (mean, 2.46). The sTL was inversely correlated with the SUVmax [sTL = -0.1004 Ln (SUVmax) + 0.4464; R²= 0.81]. The sSUV showed a linear correlation with the SUVmax (sSUV = 0.0842 SUVmax + 1.248; R²= 0.89). The sTL was not associated with the value of C-pGTVs.</p> <p>Conclusion</p> <p>In PET/CT-based BTV for HNC, a suitable threshold or SUV level can be established by correlating with SUVmax rather than using a fixed threshold.</p

Real-Time Gait Cycle Parameter Recognition Using a Wearable Accelerometry System

This paper presents the development of a wearable accelerometry system for real-time gait cycle parameter recognition. Using a tri-axial accelerometer, the wearable motion detector is a single waist-mounted device to measure trunk accelerations during walking. Several gait cycle parameters, including cadence, step regularity, stride regularity and step symmetry can be estimated in real-time by using autocorrelation procedure. For validation purposes, five Parkinson’s disease (PD) patients and five young healthy adults were recruited in an experiment. The gait cycle parameters among the two subject groups of different mobility can be quantified and distinguished by the system. Practical considerations and limitations for implementing the autocorrelation procedure in such a real-time system are also discussed. This study can be extended to the future attempts in real-time detection of disabling gaits, such as festinating or freezing of gait in PD patients. Ambulatory rehabilitation, gait assessment and personal telecare for people with gait disorders are also possible applications

Anti-Arthritic Effects of Magnolol in Human Interleukin 1β-Stimulated Fibroblast-Like Synoviocytes and in a Rat Arthritis Model

Fibroblast-like synoviocytes (FLS) play an important role in the pathologic processes of destructive arthritis by producing a number of catabolic cytokines and metalloproteinases (MMPs). The expression of these mediators is controlled at the transcriptional level. The purposes of this study were to evaluate the anti-arthritic effects of magnolol (5,5′-Diallyl-biphenyl-2,2′-diol), the major bioactive component of the bark of Magnolia officinalis, by examining its inhibitory effects on inflammatory mediator secretion and the NF-κB and AP-1 activation pathways and to investigate its therapeutic effects on the development of arthritis in a rat model. The in vitro anti-arthritic activity of magnolol was tested on interleukin (IL)-1β-stimulated FLS by measuring levels of IL-6, cyclooxygenase-2, prostaglandin E2, and matrix metalloproteinases (MMPs) by ELISA and RT-PCR. Further studies on how magnolol inhibits IL-1β-stimulated cytokine expression were performed using Western blots, reporter gene assay, electrophoretic mobility shift assay, and confocal microscope analysis. The in vivo anti-arthritic effects of magnolol were evaluated in a Mycobacterium butyricum-induced arthritis model in rats. Magnolol markedly inhibited IL-1β (10 ng/mL)-induced cytokine expression in a concentration-dependent manner (2.5–25 µg/mL). In clarifying the mechanisms involved, magnolol was found to inhibit the IL-1β-induced activation of the IKK/IκB/NF-κB and MAPKs pathways by suppressing the nuclear translocation and DNA binding activity of both transcription factors. In the animal model, magnolol (100 mg/kg) significantly inhibited paw swelling and reduced serum cytokine levels. Our results demonstrate that magnolol inhibits the development of arthritis, suggesting that it might provide a new therapeutic approach to inflammatory arthritis diseases

Gait changes in individuals with bilateral hallux valgus reduce first metatarsophalangeal loading but increase knee abductor moments

Hallux valgus (HV), one of the most common foot pathologies in modern society, affects not only the foot itself, but also the other lower limb joints. The purpose of the study was to investigate the kinematic and kinetic changes in the lower limb joints in patients with bilateral HV during level walking. Twelve female patients with bilateral HV and 12 healthy female controls walked while three-dimensional kinematic and kinetic data were measured. Patients with HV were found to shift their center of pressure (COP) laterally away from the 1st metatarsophalangeal joint (MPJ), which helped unload the joint during late stance. The lateral shift of the COP in these patients was associated with the reduced toe-out angles of the foot as a result of increased internal rotation of the hip. However, this strategy increased the abductor moments at the knee, an index closely correlated with the medial load at the knee and a predictor of the onset and progression of medial OA. Early treatment of HV may be helpful not only for reducing foot pain and deformity, but also for preventing the potentially harmful loading at the knee, especially in those at risk of medial knee OA. (C) 2014 Elsevier B.V. All rights reserved

Design and Biomechanical Analysis of Dynamic External Skeletal Fixator with Arthrodiatasis for Upper Extremity

中文摘要 外固定器已被接受用來治療上肢關節如腕關節和肘關節的骨折。我們利用現有的商用外固定器來治療病患，並將治療的結果列述於本論文中。除了分析商用外固定器的功能與原理之外，我們也提出具有動態牽引功能的外固定器設計概念。 我們也針對所設計的外固定器做了生物力學分析。首先是骨針定位與肘關節角度對外固定器軸心對位的影響。從運動學觀點來看，骨頭與外固定器的架構形成了一個封閉的連桿系統。對於具備轉軸的動態外固定器，關節的動態牽引和軸心定位必定和設備(如外固定器的設計)，手術(如骨針定位)和關節的因素(如關節角度)相關。我們針對跨肘的外固定器連桿系統於不同初始條件做數值分析，得到不少組解可以達成軸心定位。這避免了單一解在手術上困難度極高的疑慮。 此外我們也評估了肘關節角度和骨針偏折對外固定器系統的同心牽引與牽引減少的影響，因為在臨床上知道關節表面被拉伸距離的減少是有助於手術的準備計劃。我們依據具轉軸的外固定器和強化的關節韌帶建立了四個有限元素分析模型。計算並比較了尺骨側與肱骨側因外固定器拉伸所引伸的距離及骨針沿特定力傳遞路徑固定於手肘上的影響，以改善具動態牽引功能的肘外固定器的使用情形。 最後我們利用齊次轉換矩陣進行運動學分析來評估骨針施打位置與插入角度對跨腕式關節外固定器的軸心對位之影響。分析骨針定位的改變於運動學上的限制。數值分析的結果同時用三角幾何模型與電腦模擬來驗證。各個骨針定位參數的影響並用田口氏工程方法加以驗證。經此齊次轉換矩陣分析所得的各種骨針位置與角度可作為外科醫師手術時的參考。同時適當的骨釘定位與最佳的外固定器設計所提供的軸心定位功能是術後跨腕關節運動的關鍵。Abstract The external fixators have been used for the treatments of the fractures in the elbow joint and wrist joint of the upper extremity. The clinical practices using the commercial external fixators were performed and the positive results were reported in this thesis. Other than the commercial fixators of which we reviewed the function, we also proposed our conceptual design of the fixator with the arthrodiatasis. Several biomechanical analyses were performed based on the fixator of our design. Firstly we analysis the effect of the pin placement and the elbow angle on the hinge-alignment of the elbow fixator. From the kinematic viewpoint, the bone-fixator construct forms a closed linkage system. For the traditional static fixator, previous study demonstrated numerically that the placement of the fixing pins and the initial condition at the fracture site significantly restrained the fracture reduction and fixator adjustability. For the hinged dynamic fixator, the functions of joint distraction and hinge alignment might be closely related to some devices (e.g. fixator design), surgery (e.g. pin placement), and joint factors (e.g. elbow angle). In our parametric analysis of the bridged elbow-fixator linkage system under various initial configurations, there are multiple solutions to achieve hinge alignment which prevent the concerns that when only a unique solution exists for the hinge alignment, the arthrodiatasis inevitably becomes a highly technique-demanding surgery for setting the initial configuration of the bone-pin-fixator construct. Secondly we evaluated the effects of elbow angle and pin deflection on the concentric distraction and distraction loss of the elbow-fixator-pin construct since it is of clinical importance to clarify the loss between distracted distance of the articular surfaces and fixator’s distractor(s) for surgery planning. We deployed four finite-element elbow models with the unilaterally hinged fixator and stiffened periarticular tissues. The distraction values from the fixator distractor and fixing pins to the stiffened elbow, along the specified load-transferring path, were calculated and compared on both humeral and ulnar sides and thus improved the use of the elbow hinged fixator with arthrodiatasis. Thirdly we performed the kinemtic analysis to evaluate the influence of the pin locations and insertion angle to the hinge alignment of the bridging wrist joint fixator via the principle of homogeneous transformation matrix. The pin placement variables were parametrically changed to analyze their kinematic limitations. The numerical results were validated by the trigonometric model and computerized simulation. The influences of the pin placements were also evaluated with Taguchi method. The bone pin locations and orientations under different scenarios obtained from HTM analysis can be a good reference for the surgical application in the practical surgery. The current study demonstrated that the adequate pin placement and optimal fixator design which provided the hinge alignment function were critical for the postoperative bridged wrist motion.CONTENTS試委員會審定書cknowledgements..........4文摘要..................5bstract..................6igure and Table Index....8hapter 1.Introduction.....14.1 Functional anatomy and biomechanics of elbow....14.1.1 Anatomy.........................................15.1.2 Kinematic.......................................16.1.3 Stability.......................................17.1.4 Kinetic.........................................19.1.5 Further Development.............................21.2 Functional Anatomy of Hand and Wrist............21.3 Dilema of Stability and Mobility in the treatment of complex instability, contracture and fracture/dislocation.....................................23hapter 2.Treatment of Complex Elbow Injury with External Skeletal Fixator (ESF) with Arthrodiatasis...............28.1 Case Report.....................................28.1.1 Case 1..........................................28.1.2 Case 2..........................................29.2 Effects of the ESF with Arthrodiatasis in the Treatment of Complex Elbow Injury........................30hapter 3.Optimal Design of a Newly Designed Elbow ESF with Arthrodiatasis...........................................38.1 Introduction to the Commercialized Equivalent Counterparts.............................................38.2 Design Rationale of a New Elbow ESF with Arthrodiatasis...........................................40.2.1 Hinge-alignment Function........................41.2.2 Arthroplasty-distracting Function...............42.2.3 Rehabilitation-training function................42hapter 4.Design of a Newly Bridging Wrist ESF with Arthrodiatasis and Non-bridging Wrist ESF................52.1 Introduction to the Commercialized Equivalent Counterparts.............................................52.1.1 Overview........................................52.1.2 Introduction to Commercialized Bridging Wrist ESF......................................................53.1.3 Introduction to Commercialized Non-bridging Wrist ESF......................................................55.2 Design Rationale of a New Bridging ESF with Arthrodiatasis...........................................57.2.1 Hinge-alignment Function.......................57.2.2 Arthroplasty-distracting Function...............58.2.3 Rehabilitation-training Function................58.3 Design Rationale of a New Non-bridging ESF......59hapter 5.Biomechanical Influences of Pin Placement and Elbow Angle on Hinge Alignment of Hinged Elbow-Fixator Construct................................................67.1 Overview........................................67.2 Mathematical Description of the Elbow-Fixator Kinematic Linkage System.................................68.3 Result..........................................74.4 Discussion......................................76hapter 6.Analysis of Joint Distraction Loss of the Bridged Elbow by Dynamic Fixator.................................87.1 Overview........................................87.2 Hinge Elbow Model...............................88.3 Finite Element Model............................91.4 Results.........................................93.4.1 Joint Distraction...............................93.4.2 Distraction Loss................................95.5 Discussion......................................95.5.1 Joint Distraction...............................96.5.2 Distraction Loss................................98hapter 7.The Influences of the Pin Placement on the Hinge Alignment of a Newly Designed Wrist ESF.................106.1 Overview.......................................106.2 Material and Methods...........................106.2.1 The Establishemnt of the Linkage System between the Radius,etacarpal Bone and External Fixator....................106.2.2 Kinematic Geometry of the Linkage System.......108.2.3 Geometric Model of the Wrist/Fixator System....110.2.4 Effects of Individual Clinical Parameter.......111.2.5 Verification with Computer Simulation..........112.3 Results........................................112.4 Discussions....................................114hapter 8.Conclusion and Future Works...................129.1 Conclusion.....................................129.1.1 Elbow ESF with Arthrodiatasis..................129.1.2 Wrist Bridging ESF with Arthrodiatasis and Non-bridging ESF............................................130.2 Future Works...................................131題研究補助致謝........................................132eferences..............................................133ppendix Previously Published Papers...................14