Anatomic Anteversion of the Acetabular Component Correlates with Polyethylene Linear Wear in Total Hip Arthroplasty: The Three-Dimensional Numerical Analysis

Background: Although abduction of the acetabular component is considered to predict factors for polyethylene wear attributable to osteolysis, other radiographic factors have yet to be elucidated. The purpose of the present study was to evaluate whether anteversion or change in implantation angle of the acetabular component influences polyethylene linear wear by using standing and supine radiographs of the hip joint. Methods: Standing and supine plain anteroposterior radiographs of 62 hip joints in which cementless total hip arthroplasty was performed were examined for polyethylene linear wear rate (mm/year), pelvic inclination, and radiological inclination and anatomic anteversion of the acetabular component. Results: All correlation coefficients of measurements of polyethylene linear wear, pelvic inclination angle, anatomical anteversion angle and radiological inclination angle were calculated highly. And by the three-dimensional numerical analysis, anatomic anteversion of the acetabular component had at least some effect on the degree of polyethylene wear. Conclusion: This study suggests that increased anteversion of the acetabular component reduces polyethylene linear wear in metal-on-polyethylene total hiparthroplasty.

Arthroscopic approach to the posterior compartment of the knee using a posterior transseptal portal

Arthroscopic surgery of the posterior compartment ofthe knee is difficult when only two anterior portals are used for access because of the inaccessibility of the back of the knee. Since its introduction, the posterior transseptal portal has been widely employed to access lesions in the posterior compartment. However, special care should be taken to avoid neurovascular injuries around the posteromedial, posterolateral, and transseptal portals. Most importantly, popliteal vessel injury should be avoided when creating and using the transseptal portal during surgery. Purpose of the present study is to describe how to avoid the neurovascular injuries during establishing the posterior three portals and to introduce our safer technique to create the transseptal portal. To date, we have performed arthroscopic surgeries via the transseptal portal in the posterior compartments of 161 knees and have not encountered nerve or vascular injury. In our procedure, the posterior septum is perforated with a 1.5-3.0-mm Kirschner wire that is protected by a sheath inserted from the posterolateral portal and monitored from the posteromedial portal to avoid popliteal vessel injury.

Evaluation of Conservative Treatment of Acute Fracture of the Odontoid Process of Axis with a Halo-Vest

We fitted a halo-vest on patients with a fracture of the odontoid process of the axis and evaluated the effects of conservative treatment on cervical muscular atrophy and the number and type of patient complaints after bone union. Four patients had Anderson Type II fractures and 6 patients had Type III fractures. Bone union was observed in all patients within 3 months after injury. After halo-vest fitting, cervical muscular atrophy increased with time, however, it gradually improved after removal of the halo-vest. Patients fixed with a halo-vest for more than 10 weeks complained of cervical discomfort and limited range of motion. No patients with fixation for less than 10 weeks had problems in bone union or had cervical complaints. Thus, less than a 10-week fixation period was considered to be appropriate.

Biomechanical Stability of Open-Wedge High Tibial Osteotomy: Comparison of Two Locking Plates

Introduction: Recently, new plates with locking screws have been developed and used for medial open-wedge high tibial osteotomy (HTO). The purpose of this study was to evaluate and compare biomechanical properties of different internal fixations in open-wedge HTO using the two currently available locking plates. Methods: Eight paired fresh-frozen cadaveric lower extremities were vertically embedded in steel boxes. The axial compression load was applied to the legs using the mechanical testing machine. The axial compression load test from 0 N to 550 N and the failure test were performed before and after HTO. One side of the leg of a specimen was fixed with the Puddu locking plate and the other side was fixed with the TomoFix plate to compare the two plates using the same specimen. A mode of failure and vertical displacement of the medial and lateral parts of the tibia at the osteotomy gap was recorded using a video camera in the failure test. The load–displacement data were analyzed to calculate stiffness, failure load, and displacement at failure. Results: The mean failure load was 1471.4 N and 1692.3 N and total vertical displacement at failure was 3.1 mm and 2.9 mm with the Puddu and TomoFix plates, respectively. During axial compression loading, displacements mainly occurred at the lateral osteotomy gap, while the medial gap was well preserved. No significant differences were observed in the failure load, displacement, or mode of failure between the two plates. Conclusions: The Puddu and TomoFix plates had similar biomechanical properties in open-wedge HTO. The results indicated reliable stability after open-wedge HTO without fibular osteotomy.

Successful Treatment of Spine Fracture for Diffuse Idiopathic Skeletal Hyperostosis with Teriparatide—A Report of Two Cases

We experienced 2 cases of spinal fracture in patients aged 80 years or older with diffuse idiopathic skeletal hyperostosis (DISH). Since they decided not to undergo surgical treatment, we provided conservative treatment with teriparatide. There has been no previous study on teriparatide for spine fracture in DISH. This is the first report of the successful use of teriparatide to treat spine fracture in DISH without surgical intervention. Our patients were treated with teriparatide for 8-9 months after diagnosis of the fracture. Union was obtained in two cases and no adverse events were observed during treatment. Our report showed that teriparatide could be an alternative to conventional intervention in spinal fracture of DISH.

Isolated Metastatic Barrett’s Adenocarcinoma of the Thoracic Epidural Space Causing Paraplegia

Barrett’s adenocarcinoma is an esophageal cancer arising from Barrett’s esophagus. In this report, a metastatic epidural tumor from Barrett’s adenocarcinoma with paraplegia that required surgical treatment is documented. A 50-year-old man who had had a resection of the distal esophagus due to Barrett’s adenocarcinoma six month before presented with progressive weakness and numbness in lower limbs with urinary disturbance. Magnetic resonance imaging of the thoracic region revealed compression of the spinal cord at the T3-4 level by a dorsally located epidural mass. No signal changes were detected in vertebrae. Since the paraplegia and urinary disturbance were rapidly progressing, laminectomy and tumor resection was performed. Postoperatively, neurological function improved immediately and there was no recurrence of spinal region. This is the first report on an isolated metastatic Barrett’s adenocarcinoma of the thoracic epidural space.

An Earth-mass planet in a time of COVID-19:KMT-2020-BLG-0414Lb

We report the discovery of KMT-2020-BLG-0414 Lb,with a planet-to-host mass ratio q2=0.9-1.2×10-5=3-4 q⊕at 1σ,which is the lowest mass-ratio microlensing planet to date.Together with two other recent discoveries(4?q/q⊕?6),it fills out the previous empty sector at the bottom of the triangular(log s,log q)diagram,where s is the planet-host separation in units of the angular Einstein radiusθE.Hence,these discoveries call into question the existence,or at least the strength,of the break in the mass-ratio function that was previously suggested to account for the paucity of very low-q planets.Due to the extreme magnification of the event,Amax~1450 for the underlying single-lens event,its light curve revealed a second companion with q3~0.05 and|log s3|~1,i.e.,a factor~10 closer to or farther from the host in projection.The measurements of the microlens parallaxπE and the angular Einstein radiusθE allow estimates of the host,planet and second companion masses,(M1,M2,M3)~(0.3 M⊙,1.0 M⊕,17 MJ),the planet and second companion projected separations,(a⊥,2,a⊥,3)~(1.5,0.15 or 15)au,and system distance DL~1 kpc.The lens could account for most or all of the blended light(I~19.3)and so can be studied immediately with high-resolution photometric and spectroscopic observations that can further clarify the nature of the system.The planet was found as part of a new program of high-cadence follow-up observations of high-magnification events.The detection of this planet,despite the considerable difficulties imposed by COVID-19(two KMT sites and OGLE were shut down),illustrates the potential utility of this program.

数码航空影像在建筑物震害信息提取中的应用

近几年被引入到航空摄影的数码航空相机,其辐射分辨率比传统的胶片航空相机高很多。因此,即使空间分辨率在同一水平,数码航空相机也能比胶片相机获取更清晰的地面影像。本文重点强调数码航空相机探测多种地震灾害的能力。数码航空相机、模拟航空相机和高分辨率卫星影像拍摄到了最近日本发生的几次地震的受灾地区,如2004年新泻中越地震和2007年新泻中越冲地震。本文首先进行了数码航空影像与扫描式模拟照片质量间的对比。然后对2007年新泻中越冲地震震前、震后拍摄的数码航空影像,应用了基于像元与基于对象两种分类方法提取出建筑破坏信息。经过一系列的数字图像处理后,倒塌建筑物的瓦砾被准确地提取出来。

轴向游隙对双列圆锥滚子轴承滚动体载荷分布的影响

利用埋入式光纤传感器,测量了双列圆锥滚子轴承的滚动体载荷,研究了轴向游隙对滚动体载荷的影响。结果表明,滚动体载荷分布系数随轴向游隙的增大而减小。

Transfer of electrons on scratched iron surfaces:Photoelectron emission and X-ray photoelectron spectroscopy studies

We report the activation energy, ΔEa, for the quantum yield in thermally assisted photoelectron emission(TAPE) under 210-nm-wavelength light irradiation, and the associated X-ray photoelectron spectroscopy(XPS) results. Samples were cleaned only in acetone and scratched in air, water, methanol, ethanol, acetone, benzene, and cyclohexane. Glow curves, describing the temperature dependence of photoelectron emission(PE) quantum yield(emitted electrons/photon), Y, were obtained. A simple method of determining ΔEa using Y, called YGC, at seven temperatures up to 353 °C, for the same Y glow curve, was proposed. The ΔEa obtained using this method was almost the same as that obtained from Y for seven stationary temperatures(YST). For scratched samples, the TAPE was measured over two cycles of temperature increase and subsequent decrease(Up1, Down1 and Up2, Down2 scans) in the 25–339 °C range, and ΔE_a was obtained from YGC. The Arrhenius plot was approximated by a straight line, although a convex swelling peak appeared in the Up1 scan. ΔE_(aUp1) was in the 0.212–0.035 eV range, depending on the environment in which scratching was performed; ΔE_(aUp1) for water was much higher than that for acetone. This was explained in terms of the mode of the acid–base interaction between the liquid molecules and the hydroxyl group of Fe–OH. The values of ΔE_(aDown1), ΔEa Up2, and ΔE_(aDown2) were in the 0.038–0.012 eV range. The total count of electrons emitted during the Up1 and Up2 scans was found to decrease with increasing ΔE_(aUp1) and ΔE_(aUp2), respectively. ΔE_(aUp2) was found to increase with increasing presence of the FeO component in the analyzed Fe oxides. The convex swelling peak was attributed to the removal of carbon materials from the scratched surface and the effect of the increased electron density of the surface hydroxyl group of FeOH under the light irradiation.