Effects of anteriorly-loaded treadmill walking on dynamic gait stability in young adults

BackgroundAnteriorly-loaded walking is common in many occupations and may increase fall risk. Dynamic gait stability, defined by the Feasible Stability Region (FSR) theory, quantifies the kinematic relationship between the body’s center of mass (COM) and base of support (BOS). FSR-based dynamic gait stability has been used to evaluate the fall risk.Research questionHow does front load carriage affect dynamic gait stability, step length, and trunk angle among young adults during treadmill walking?MethodsIn this between-subject design study, 30 healthy young adults were evenly randomized into three load groups (0%, 10%, or 20% of body weight). Participants carried their assigned load while walking on a treadmill at a speed of 1.2 m/s. Body kinematics were collected during treadmill walking. Dynamic gait stability (the primary variable) was calculated for two gait events: touchdown and liftoff. Step length and trunk angle were measured as secondary variables. One-way analysis of variance was conducted to detect any group-related differences for all variables. Post-hoc analysis with Bonferroni correction was performed when main group differences were found.ResultsNo significant differences but medium to large effect sizes were found between groups for dynamic gait stability at touchdown (p = 0.194, η² = 0.114) and liftoff (p = 0.122, η² = 0.139). Trunk angle significantly increased (indicating backward lean) with the front load at touchdown (p < 0.001, η² = 0.648) and liftoff (p < 0.001, η² = 0.543). No significant between-group difference was found related to the step length (p = 0.344, η² = 0.076).SignificanceCarrying a front load during walking significantly alters the trunk orientation and may change the COM-BOS kinematic relationship and, therefore, fall risk. The findings could inform the design of future studies focusing on the impact of anterior load carriage on fall risk during different locomotion.     

Reliability and criterion validity of two-dimensional movement assessments in those with patellofemoral pain

ObjectivesDetermine criterion validity and intra/inter-rater reliability of 2-dimensional (2D) knee frontal plane projection angle (kFPPA), hip frontal plane projection angle (hFPPA), and dynamic valgus index (DVI) during forward step-downs in those with patellofemoral pain (PFP).DesignCross-sectional.SettingUniversity research laboratory.Participants39 participants with PFP (34.18 ± 7.41years, 170± .1 cm, 81.03 ± 19.36 kg, duration of pain: 68.67 ± 85.08months, anterior knee pain scale: 80.49 ± 7.87, visual analog scale:2.08 ± 2.02)Main outcome measuresAverage 3D hip and knee sagittal, frontal, and transverse joint angles and 2D kFPPA, hFPPA, and DVI at maximum knee flexion were variables of interest. 3D DVI was calculated as the sum of hip and knee frontal and transverse angles. 2D kFPPA, hFPPA, and DVI were calculated by two raters independently on two occasions.ResultsIntra- and inter-rater reliability of all 2D angles were excellent. kFPPA was moderately correlated to 3D knee transverse angles. hFPPA was moderately correlated to 3D hip frontal and transverse angles and largely correlated to 3D DVI. 2D DVI was moderately correlated to hip transverse angles.ConclusionkFPPA, hFPPA, and DVI are reliable. hFPPA may be reflective of 3D hip and knee frontal and transverse motion during forward step-downs in those with PFP.     

Association of quadriceps angle with plantar pressure distribution,navicular height and calcaneo-tibial angle

ObjectiveThe aim of study was to analyze the association between Quadriceps Angle (QA) and plantar pressure, navicular height (NH), and calcaneo-tibial angle (CTA).MethodsA total of 64 volunteers (mean age: 22.25 ± 2.54 (range:19–33)) participated in this cross sectional study. EMED-m (Novel GmbH, Germany) electronic pedobarograph was employed for dynamic plantar pressure measurement using two step protocol. The angle between the vertical axis of calcaneus and the long axis of Achilles tendon for CTA. The height of navicular tubercle from the ground was measured while the subject was standing on both feet for NH. QA was measured while the subject was standing in a relaxed posture where both feet bearing equal weight.ResultsThere were significant negative correlations between QA and maximum force (MxF) under the 4th. metatarsal head (MH4). The QA was also significantly correlated with MxF and force-time integral (FTI) under the bigtoe (BT). FTI under the 3rd. metatarsal head (MH3), MH4 and 5th. metatarsal head (MH5) were significantly negatively correlated with QA. Pressure-time integral (PTI) under the MH4 and MH5 were found to be significantly negatively correlated with QA. A significant correlation was also found between QA and NH (p < 0.0001), whilst there was no correlation between QA and CTA. Regression analysis showed that NH was appeared as the major contributor for the QA (β = −0.49, p < 0.001) in the dynamic condition, followed by BT-FTI (β = 0.37, p < 0.001) and MH5-MxF (β = −0.21, p < 0.037).ConclusionThese findings may imply that the NH which can at least be controlled by appropriate shoe inserts may affect QA. This way, loading pattern of both plantar region and whole lower extremity may be altered.Level of evidenceLevel III, Diagnostic Study.     

Symptom improvement in dry eye subjects following intranasal tear neurostimulation: Results of two studies utilizing a controlled adverse environment

PurposeTo evaluate the safety and effectiveness of the intranasal tear neurostimulator (ITN) in improving dry eye symptoms assessed in a controlled adverse environment (CAE®).MethodsStudy 1: Multicenter, subject-masked, randomized-sequence, crossover design. Single intranasal (active) and extranasal (control) ITN administration during CAE exposure. Study 2: Single-arm, open-label design. Intranasal ITN administration ≥2 times/day for 45 days, CAE assessment at days 0 and 45. In both studies, upon CAE entry, and every 5 min thereafter, subjects assessed eye dryness score (visual analog scale, 0–100 mm; EDS-VAS), and ocular discomfort score (ODS; Ora Calibra™, 0–4), for ≈2 h. Study 1: when ODS was ≥3 at 2 consecutive timepoints, subjects applied ITN intranasally or extranasally for ≈3 min, and again when achieving the same ODS criteria in randomized sequence. Study 2: days 0 and 45, ITN was applied for ≈3 min employing the same ODS criteria as Study 1.ResultsStudy 1: Significantly greater pre- to post-application reductions in mean [SEM] EDS (−16.5 [1.7] vs −3.1 [1.7], P < 0.0001) and ODS (−0.93 [0.08] vs −0.34 [0.08], P < 0.0001; n = 143) with intranasal vs extranasal stimulation. Study 2: On day 0 (n = 52) and day 45 (n = 48), significant pre- to post-application reductions in mean [SEM] EDS (−15.9 [2.7] and −15.2 [2.4]; P < 0.0001), and ODS (−1.3 [0.2] and −1.3 [0.1]; P < 0.0001). Few device-related adverse events were reported, none serious.ConclusionsAcute symptom relief is significant with the ITN and remains undiminished after daily use.     

Monolithic crowns fracture analysis: The effect of material properties,cusp angle and crown thickness

ObjectivesThis study aimed to investigate the collective influence of material properties and design parameters on the fracture behavior of monolithic dental crowns.MethodsThree-dimensional (3D) models (N = 90) with different combinations of design parameters (thickness, cusp angle and occlusal notch geometry) and material type (lithium disilicate, feldspar ceramic, zirconia, hybrid resin ceramic and hybrid polymer-infiltrated ceramic) were developed for the failure analysis using extended finite element method (XFEM) to identify the stress distribution, crack initiation load, fracture surface area and fracture pattern. Analytical formulation, in vitro fracture tests and fractographic analysis of dedicated models were also performed to validate the findings of the XFEM simulation.ResultsFor all material types considered, crowns with a sharp occlusal notch design had a significantly lower fracture resistance against occlusal loading. In most of the models, greater crown thickness and cusp angle resulted in a higher crack initiation load. However, the effect of cusp angle was dominant when the angle was in the low range of 50° for which increasing thickness did not enhance the crack initiation load.SignificanceComparing the critical load of crack initiation for different models with the maximum biting force revealed that for the studied monolithic materials excluding zirconia, a design with a rounded occlusal notch, 70° cusp angle and medium thickness (1.5 mm occlusal) is an optimum combination of design parameters in terms of tooth conservation and fracture resistance. Zirconia crowns exhibited sufficient strength for a more conservative design with less thickness (1.05 mm occlusal) and sharper cusp angle (60°).     

浅析茯苓“角药”在《伤寒杂病论》中的配伍与应用

"角药"是由3味中药联合应用、配伍而成,相辅相成,互为犄角。《伤寒杂病论》中包含着大量的角药运用,根据其在方剂中发挥作用的不同。文章分别从独立成方、方剂中主要作用、方剂中次要或辅助作用以及多组角药联合作用4个方面对经方中茯苓"角药"进行详细的梳理和分析,以期为临床提供指导与参考。     

唑来膦酸联合椎体后凸成形治疗骨质疏松性压缩骨折：提高骨密度、预防椎体再骨折、远期疗效评价的Meta分析

文题释义：椎体后凸成形：采用椎体内置入气囊的方法通过扩张使椎体复位，在椎体内部形成空隙，减小骨水泥注入所需的推力，使骨水泥在椎体内不易流动，可有效解除或缓解疼痛、恢复病椎高度，但临床发现仍存在骨水泥渗漏等风险。 唑来膦酸：椎体后凸成形已被广泛应用于骨质疏松性压缩骨折的治疗，临床疗效显著，然而如何有效改善骨质疏松状况成为临床面临的重要问题。唑来膦酸是双膦酸盐类药物，可有效抑制骨吸收，降低再发骨折风险，改善骨折患者的功能评分。 背景：临床应用唑来膦酸治疗骨质疏松症缺乏系统的科学评价和循证学依据，因此目前对于唑来膦酸联合椎体后凸成形治疗骨质疏松性椎体压缩骨折的临床疗效尚无明确定论。 目的：系统评价唑来膦酸联合椎体后凸成形治疗骨质疏松性椎体压缩骨折的临床疗效。 方法：应用计算机检索公开发表在CNKI、万方、维普等中文数据库及CBM、PubMed、Cochrane等英文数据库中，有关唑来膦酸联合椎体后凸成形治疗骨质疏松性椎体压缩骨折的随机对照试验，试验组治疗方式为唑来膦酸联合椎体后凸成形，对照组治疗方式为椎体后凸成形，时间截止至2019年9月。由2位研究员独立进行文献筛选、数据提取，按Cochrane协作网标准对纳入随机对照试验逐个进行质量评价，采用RevMan 5.3软件对符合纳入标准的研究进行统计分析。 结果与结论：①最终纳入5篇文献，均为随机对照研究，试验组患者175例，对照组患者184例；②统计分析结果显示：试验组治疗后12个月的骨密度高于对照组[MD=0.12，95%CI(0.08，0.17)，P < 0.000 01]，治疗后6，12个月的目测类比评分低于对照组[MD=0.46，95%CI(0.18，0.75)，P=0.002；MD=0.85，95%CI(0.20，1.50)，P=0.01]，治疗后1年的Oswestry功能障碍指数评分低于对照组[MD=6.59，95%CI(4.77，8.41)，P < 0.000 01]，骨水泥渗漏率、椎体骨折再发率低于对照组[OR=0.22，95%CI(0.08，0.59)，P=0.003；OR=0.18，95%CI(0.07，0.50)，P=0.000 8]；两组椎体高度恢复、椎体后凸Cobb角比较差异无显著性意义[MD=0.65，95%CI(-0.27，1.56)，P=0.16；MD=-0.60，95%CI(-2.45，1.25)，P=0.53]；③结果表明与单独应用椎体后凸成形相比，唑来膦酸联合椎体后凸成形在提高骨密度值、减少椎体骨折再发率、改善患者远期临床症状、预防骨水泥骨水泥渗漏等并发症方面具有显著优势，但后期仍需大量高质量的多中心随机对照研究提供更充足的证据。 ORCID: 0000-0001-8871-3539(李凯明) 中国组织工程研究杂志出版内容重点：人工关节；骨植入物；脊柱；骨折；内固定；数字化骨科；组织工程