Clinical course of masticatory function recovery following arthrocentesis in patients with unilateral mandibular condyle head fracture

The aim of this study was to investigate the clinical course of masticatory function recovery following arthrocentesis. Patients with a unilateral condylar head fracture who underwent arthrocentesis for therapeutic reasons were evaluated and compared with patients with a unilateral condylar head fracture who did not undergo arthrocentesis. At 3 months after treatment, the occlusal contact area and maximum bite force in patients with a fracture treated with arthrocentesis were greater than in those who did not receive arthrocentesis at the same time points, although the differences were not significant. Moreover, at 1 and 3 months following arthrocentesis, mean (±SD) occlusal contact area (1 month: 1.99 ± 0.55 mm², p = 0.01; 3 months: 2.90 ± 1.36 mm², p = 0.03) and maximum bite force (1 month: 82.45 ± 15.04 N, p = 0.01; 3 months: 101.11 ± 14.53 N, p = 0.01) on the fractured side in patients who underwent that treatment were significantly reduced when compared with those on the non-fractured side. The authors conclude that if the priority is to avoid open reduction and internal fixation, then the arthrocentesis approach might be a less invasive alternative, albeit with the price of a prolonged healing interval.     

Effects of running-induced fatigue on plantar pressure distribution in runners with different strike types

BackgroundRunning induced-fatigue is an important factor in running related injuries. Runners with different strike types have different running mechanics and suffer from different injury patterns. Underlying mechanism of this difference is not well understood.Research questionThe aim of this study was to examine the effects of running-induced fatigue on plantar pressure distribution in runners with different strike types.Methods30 rearfoot (age = 21.56 ± 2.28 years; height = 1.67 ± 0.08 m; mass = 61.43 ± 11.57 kg; BMI = 21.77 ± 2.9 kg∙m⁻²) and 30 forefoot (age = 19.73 ± 1.68 years; height = 1.71 ± 0.08 m; mass = 65.7 ± 13.45; BMI = 22.53 ± 3.39 kg∙m⁻²) strike male and female recreational runners were recruited to this study. Participants ran in 3.3 m/s barefoot along the plantar pressure measuring device (Footscan®, Rsscan International) before and after running-induced fatigue. Fatigue protocol was performed on a treadmill. Peak plantar pressure and peak plantar force (% body weight), contact time and medio-lateral force ratio were calculated while running. Repeated measures ANOVA test was used to investigate the effect of running-induced fatigue on plantar pressure variables (p ≤ 0.05).ResultsAfter running-induced fatigue, in the rearfoot strike group, increases in loading of medial and lateral portions of the heel, first metatarsal and big toe was observed, and in lesser toes and in the forefoot push off phase, the medio-lateral force ratio decreased. While, in the forefoot strike group first to third metatarsals loading increased and fifth metatarsal loading decreased after fatigue, and medio-lateral force ratio in the foot flat and forefoot push off phase increased. In both groups contact time increased after fatigue.SignificanceOur data indicate that running-induced fatigue has different effects on plantar pressure distribution pattern in runners with different strike type. These different effects reflect different adaptation strategies in runners with different strike types, and could explain existence of different injury patterns in runners with different strike types.     

Change in Pull-Out Force during Resorption of Magnesium Compression Screws for Osteosynthesis of Mandibular Condylar Fractures

Background: Magnesium has been used as degradable fixation material for osteosynthesis, but it seems that mechanical strength is still a current issue in these fixations. The aim of this study was to evaluate the axial pull-out force of compression headless screws made of magnesium alloy during their resorption. Methods: The tests included screws made for osteosynthesis of the mandible head: 2.2 mm diameter magnesium alloy MgYREZr (42 screws) and 2.5 mm diameter polylactic-co-glycolic acid (PLGA) (42 pieces, control). The screws were resorbed in Sørensen’s buffer for 2, 4, 8, 12, and 16 weeks, and force was measured as the screw was pulled out from the polyurethane block. Results: The force needed to pull the screw out was significantly higher for MgYREZr screws than for PLGA ones (p < 0.01). Within eight weeks, the pull-out force for MgYREZr significantly decreased to one third of its initial value (p < 0.01). The dynamics of this decrease were greater than those of the pull-out force for PLGA screws (p < 0.05). After these eight weeks, the values for metal and polymer screws equalized. It seems that the described reduction of force requires taking into account when using magnesium screws. This will provide more stable resorbable metallic osteosynthesis.     

Digital bathroom scales with open source software provide valid dynamic ground reaction force data for assessment and biofeedback

BackgroundMeasuring dynamic vertical ground reaction force allows for assessment of important clinical and physical capacity factors such as weight bearing asymmetry, force distribution, and rate of force development. However, current technologies for accurately assessing ground reaction force are typically expensive.Research QuestionThe aim of this study was to examine the validity and reliability of obtaining static and dynamic ground reaction force data from low-cost modified digital bathroom scales.MethodsFour modified bathroom scales, two units each of two different brands, were examined. Repeated mechanical loading trials were performed with known loads ranging from 0.01 to 65 kg, with acquired data compared against the known loading to calculate accuracy, hysteresis, and non-linearity. Dynamic trials consisting of 5 times sit-to-stand and weight-shifting were performed by 32 adults. Absolute and relative agreement intraclass correlation coefficient, and Pearson’s and Spearman’s correlations were performed to determine validity and reliability for the mechanical tests. Bland-Altmann plots were created for each comparison. Mean absolute error (MAE) and unbiased cross-correlation were performed on the dynamic data, comparing the calibrated data to the known values from a Bertec force platform.ResultsHysteresis and non-linearity were excellent (<0.2 % full-scale), and mechanical test results showed excellent reliability and validity. Cross-correlation results for the dynamic data were excellent, however MAE for the more rapid sit-to-stand task was higher than the slower weight-shifting test. This may have been due to the low default sampling rate for the lowest noise setting of the HX711 amplifier (10 Hz).SignificanceIn summary, our results suggest that digital bathroom scales can be easily and inexpensively modified to obtain accurate vertical ground reaction force data, with sensitivity to detect changes of as little as 0.01 kg.     

运动学对线应用于全膝关节置换术的研究进展

全膝关节置换术是目前治疗终末期膝关节骨性关节炎最有效的方法之一，全膝关节置换术后膝关节功能、术后膝关节疼痛与术后下肢力线有着密切的关系。目前膝关节置换术下肢对线方式主要采用机械力学对线方法，该方法可以改善膝关节功能，但是有部分患者也会产生术后膝关节的疼痛、活动受限等并发症，导致术后患者满意度较差。近些年越来越多的研究开始关注运动力学对线技术并应用于临床。运动学对线技术旨在重建患者的解剖结构，将膝关节假体运动轴与膝关节生理性运动轴保持一致，减少膝关节周围软组织和韧带的松解，实现膝关节生理性运动。该文就运动力学对线方法在全膝关节置换术中的应用进展作一综述。     

Input representations and classification strategies for automated human gait analysis

BackgroundQuantitative gait analysis produces a vast amount of data, which can be difficult to analyze. Automated gait classification based on machine learning techniques bear the potential to support clinicians in comprehending these complex data. Even though these techniques are already frequently used in the scientific community, there is no clear consensus on how the data need to be preprocessed and arranged to assure optimal classification accuracy outcomes.Research questionIs there an optimal data aggregation and preprocessing workflow to optimize classification accuracy outcomes?MethodsBased on our previous work on automated classification of ground reaction force (GRF) data, a sequential setup was followed: firstly, several aggregation methods – early fusion and late fusion – were compared, and secondly, based on the best aggregation method identified, the expressiveness of different combinations of signal representations was investigated. The employed dataset included data from 910 subjects, with four gait disorder classes and one healthy control group. The machine learning pipeline comprised principle component analysis (PCA), z-standardization and a support vector machine (SVM).ResultsThe late fusion aggregation, i.e., utilizing majority voting on the classifier's predictions, performed best. In addition, the use of derived signal representations (relative changes and signal differences) seems to be advantageous as well.SignificanceOur results indicate that great caution is needed when data preprocessing and aggregation methods are selected, as these can have an impact on classification accuracies. These results shall serve future studies as a guideline for the choice of data aggregation and preprocessing techniques to be employed.     

多力视角下社会资本参与基层卫生服务的动力机制及优化策略研究

社会办医作为我国基层卫生服务的重要组成部分,可以弥补基层卫生机构发展总量与质量不足等问题,对于推进整个基层卫生服务高质量发展也是有着重大裨益。文章从物理学的"力"出发,运用支持力,推力,引力,阻力,摩擦力五种"力"探讨社会资本参与基层卫生服务的动力形成机制,并构建动力斜坡图,针对存在问题,提出加大支持力和引力,合理利用推力,减少摩擦力,消除阻力等优化建议,以期助力社会资本参与基层卫生服务建设平稳进行。