Endurance Behavior of Cemented Tibial Tray Fixation Under Anterior Shear and Internal-External Torsional Shear Testing: A New Methodological Approach

BackgroundEarly total knee arthroplasty failures continue to surface in the literature. Cementation technique and implant design are two of the most important scenarios that can affect implant survivorship. Our objectives were to develop a more suitable preclinical test to evaluate the endurance of the implant-cement-bone interface under anterior shear and internal-external (I/E) torsional shear testing condition in a biomechanical sawbones.MethodsImplants tested included the AS VEGA System PS and the AS Columbus CR/PS (Aesculap AG, Germany), with zirconium nitride (ZrN) coating. Tibial implants were evaluated under anterior shear and I/E torsional shear conditions with 6 samples in 4 test groups. For the evaluation of the I/E torsional shear endurance behavior, a test setup was created allowing for clinically relevant I/E rotation with simultaneous high axial/tibio-femoral load. The test was performed with an I/E displacement of ±17.2°, for 1 million cycles with an axial preload of 3,000 N.ResultsAfter the anterior shear test an implant-cement-bone fixation strength for the AS VEGA System tibial tray of 2,674 ± 754 N and for the AS Columbus CR/PS tibial tray of 2,177 ± 429 N was determined (P = .191). After I/E rotational shear testing an implant-cement-bone fixation strength for the AS VEGA System PS tray of 2,561 ± 519 N and for the AS Columbus CR/PS tray of 2,824 ± 515 N was resulted (P = .39).ConclusionBoth methods had varying degrees of failure modes from debonding to failure of the sawbones foam. These two intense biomechanical loading tests are more strenuous and more representative of clinical activity.     

Breast Elastography: How to Perform and Integrate Into a “Best-Practice” Patient Treatment Algorithm

Breast elastography has been available for more than 15 years but is not widely incorporated into clinical practice. Many publications report extremely high accuracy for various breast elastographic techniques. However, results in the literature are extremely variable. This variability is most likely due to variations in technique, a relatively steep learning curve, and variability in methods between vendors. This article describes our protocol for performing breast elastography using both strain elastography and shear wave elastography, which produces high sensitivity and specificity. Additionally, we will describe the most commonly known false-positive and false-negative lesions as well as how to detect them.     

裘昌林教授从伏风宿痰辨治神经系统“怪病”

[目的]总结裘昌林教授诊疗神经系统“怪病”的临床经验。[方法]通过复习相关中医文献、跟师临证、整理医案等方式，总结裘师治疗神经系统疑难病的病因病机、辨治思路、用药特色，并举验案一则以示临床应用。[结果]裘师认为，伏风内潜系“怪病”的病因，宿痰内停为“怪病”之夙根，风痰合而为患故见“奇证”，治疗上以搜风豁痰为大法，将涤痰汤作为搜风豁痰的基础方，在此基础上对平时深潜体内之伏风，适量选用虫类药搜风通络以增强临床疗效。所举验案中患儿辨证为肝旺脾虚、风痰阻络，经豁痰息风、清热平肝治疗后，收效良好。[结论]神经系统“怪病”因反复发作，严重影响患者的生活质量。裘昌林教授从伏风宿痰辨治神经系统“怪病”，经验独到，值得临床推广。     

基于“内脏高敏感理论”辨治腹泻型肠易激综合征经验举隅

现代医学认为内脏高敏感与肠易激综合征的发生有重要联系。笔者从“风气内动”理论出发，阐述“内脏高敏感理论”与腹泻型IBS病机，认为脾胃失和，脾虚湿蕴，土壅侮木，肝郁生风是主要病机，故治疗本病以柔肝理脾，胜湿止泻为基本治法。选方以过敏煎为主方，过敏煎具有滋阴息风，缓急止痛，健脾除湿，涩肠止泻的功效，因此治疗腹泻型IBS临床疗效显著。