A systematic review and meta-analysis of fall incidence and risk factors in elderly patients after total joint arthroplasty

Background:Falls in the elderly have become a serious social problem worldwide. Approximately a third of persons fall at least once in the year after total joint arthroplasty (TJA), but preventing and treating falls is still challenging in clinical practice. Until now, no formal systematic review or meta-analysis was performed to summarize the risk factors of falls after TJA. The present study aimed to quantitatively and comprehensively conclude the risk factors of falls after TJA in elderly patients.Methods:The electronic databases to be searched include CNKI, Embase, Medline, and Cochrane central database (all up to November 2018). All studies on the risk factors of falls after TJA in elderly patients without language restriction were reviewed. Process of evaluation of identified studies and extraction of data were independently conducted by 2 reviewers, qualities of included studies were assessed using the Newcastle–Ottawa Scale. Data were pooled and a meta-analysis completed. All analyses were performed by the software Stata 11.0.Results:A total of 14 studies were included, which altogether included 1284456 patients with TJA, of them 12879 cases of falls occurred after surgery, suggesting the accumulated incidence of 13.1% and the prevalence of in-hospital falls was 1.0%. This study has provided evidence for the preventing of falls in the elderly patients who were underwent TJA. Outcome measures include advanced age, female, Overweight (BMI≥25 kg/m²), falls history, use of walking aid, diabetes, cardiac disease, hypertension, COPD and depressive symptoms. The ABC Scale was significantly negatively correlated with falls after lower extremity joint replacement.Conclusions:Related prophylaxis strategies should be implemented in elderly patients involved with above-mentioned risk factors to prevent falls after TJA.     

From the Cover: Functional changes of the reward system underlie blunted response to social gaze in cocaine users

Social interaction deficits in drug users likely impede treatment, increase the burden of the affected families, and consequently contribute to the high costs for society associated with addiction. Despite its significance, the neural basis of altered social interaction in drug users is currently unknown. Therefore, we investigated basal social gaze behavior in cocaine users by applying behavioral, psychophysiological, and functional brain-imaging methods. In study I, 80 regular cocaine users and 63 healthy controls completed an interactive paradigm in which the participants’ gaze was recorded by an eye-tracking device that controlled the gaze of an anthropomorphic virtual character. Valence ratings of different eye-contact conditions revealed that cocaine users show diminished emotional engagement in social interaction, which was also supported by reduced pupil responses. Study II investigated the neural underpinnings of changes in social reward processing observed in study I. Sixteen cocaine users and 16 controls completed a similar interaction paradigm as used in study I while undergoing functional magnetic resonance imaging. In response to social interaction, cocaine users displayed decreased activation of the medial orbitofrontal cortex, a key region of reward processing. Moreover, blunted activation of the medial orbitofrontal cortex was significantly correlated with a decreased social network size, reflecting problems in real-life social behavior because of reduced social reward. In conclusion, basic social interaction deficits in cocaine users as observed here may arise from altered social reward processing. Consequently, these results point to the importance of reinstatement of social reward in the treatment of stimulant addiction.Cocaine dependence is a chronically relapsing disorder defined by uncontrolled and compulsive drug use (1). Despite severe negative consequences including disrupted social relationships, loss of employment, and somatic and psychiatric illnesses, an addicted person’s life is often centered around the drug of choice and activities related to it (2). Therefore, drug use is classified as a major social, legal, and public health problem (3). After cannabis, cocaine is the second most prevalent illegal drug in the United States and Europe (4, 5), with a lifetime prevalence among young adults of 6.3% in Europe (15- to 34-y-olds) (4) and 13.3% in the United States (18- to 25-y-olds) (5).Social cognition and social support for drug users are of great clinical relevance, as they have been reported to influence onset of drug use and development of substance use disorders, and treatment success in patients with substance use disorders (6, 7). Impairments in social cognition may augment the risk of social isolation, aggression, and depression, likely supporting the vicious circle of drug use (8). Additionally, impaired social cognition may contribute to the decay of social relationships in addicted patients (9) with negative consequences for treatment success given that higher social support predicted longer abstinence duration (10). Furthermore, no efficient pharmacological treatment for cocaine addiction is currently available (11), and treatment approaches such as cognitive behavioral therapy rely, at least in part, on the emotional responsiveness and social abilities of drug users (12). Previous results suggest that cocaine users (CUs) show impairments in different facets of social cognition, particularly in emotional empathy, mental perspective taking, and emotion recognition in prosody, which are related to deficits in real-life social behavior such as fewer social contacts and more criminal offenses (13, 14). Furthermore, in money distribution games, CUs act more self-servingly and less altruistically than stimulant-naïve controls (15). Volkow et al. (9) postulated that neuroadaptations in the reward systems of drug users (e.g., ventral striatum and orbitofrontal cortex) alter reward processing such that the value of the abused drug is enhanced and concurrently the value of nondrug rewards, including social interaction, is reduced. Consequently, general social competence might become impaired and promote antisocial and criminal behavior. This may explain why social consequences of drug use (e.g., imprisonment or familial problems) do not prompt drug-addicted people to quit using the drug as well as how they contribute to increased drug use and transition from recreational drug use to addiction (9). However, whereas altered processing of monetary rewards has been reported in CUs (16), social reward processing has not been studied yet, neither on the psychological nor the neural level. Therefore, it remains elusive whether CUs (i) show behavioral differences to reward stemming from social interactions and, if so, (ii) which neural adaptations within reward circuitry underlie these potential changes in social interaction behavior.An essential part of social interaction is the phenomenon of “social gaze,” which has two aspects: Gaze can be used by the gazing person as a deictic cue to manipulate the attention of others, and can be read out by observers as a hint toward attentional focus of the gazing person (17). Both aspects can converge in joint attention (JA), which is a central element of social interaction (18) and is established when a person follows the direction of another person’s gaze so that both attend to the same object (19). Engagement in JA is considered to reflect our understanding of another person’s point of view (20). The capacity of JA emerges at 8–12 mo of age (21) and is predictive for later language learning (22) and the development of more advanced social skills such as mental perspective taking (e.g., the attribution of intentions and goals to others, also known as theory of mind) (23). Impaired JA is a core symptom of autism spectrum disorders (24).To test for social gaze differences between CUs and healthy controls (HCs), we applied a paradigm designed to capture the reciprocal and interactive nature of JA (25) (Fig. S1), where participants engage in an online interaction with an anthropomorphic virtual character in real time. Compared with self-initiated nonjoint attention (NJA; i.e., if the counterpart does not follow one’s gaze but rather pays attention to another object), self-initiated JA (i.e., if the counterpart follows one’s own gaze) is perceived as more pleasurable and associated with stronger activation of reward-related brain areas in healthy controls (25). This rewarding nature of JA might underlie the human motivation to engage in the sharing of experiences that emerges in early childhood (22, 25).It has been suggested that changes in social reward processing might underlie alterations in social behavior and cognition in CUs (9). Here we conducted two studies assessing JA processing, which constitutes an elegant approach to investigate basic social interaction patterns related to social reward processing (25), in CUs and stimulant-naïve HCs by means of behavioral, psychophysiological, and functional brain-imaging methods. In study I, a large sample of relatively pure CUs with few psychiatric comorbidities (n = 80) and stimulant-naïve HCs (n = 63) completed an interactive JA task (25) while valence and arousal ratings, error scores, reaction time, and pupil size were obtained. Pupil dilation provides an objective index of affective processing (26, 27). Based on the observations obtained in study I, we further investigated the neural correlates of the blunted emotional response to social gaze in subsamples of 16 CUs and 16 HCs using functional magnetic resonance imaging (fMRI) during an abridged version of the paradigm (study II). We hypothesized that altered emotional responses to JA are accompanied by less pronounced activation in reward-related brain areas of CUs.     

Comparison of some intrinsic risk factors of shoulder injury in three phases of menstrual cycle in collegiate female athletes

Objectivespresent study aims to investigate the changes in the shoulder joint stability factors during the menstrual cycle.Designcross-sectional study;Settinglaboratory.Participants15 healthy collegiate female athletes with normal menstrual cycles.Main outcome measuresshoulder strength, proprioception, laxity and functional stability were the primary outcomes. Participants were assessed in three phases (mense, ovulation, midluteal (day 21) by 4 different categories of tests, each designed for a different factor. Shapiro-Wilk Test was used to determine normality of data, ANOVA and Friedman Test were used to compare results. Significance level and alpha were considered 95 percent and ≥0.05, respectively. Data shown a relation between proprioception, strength and menstrual cycle.Resultsshoulder strength was significantly increased in ovulation phase compared to other phases (p < 0.5) (effect size >0.14). Proprioception was significantly decreased in luteal phase than in mense and ovulation phases (p < 0.5) (effect size >0.14). Finally, ligament laxity and functional stability showed no change in all phases (p < 0.5).ConclusionMenstrual cycle and sexual hormones affect muscle strength and proprioception of shoulder joint, but have no effect on ligament laxity and functional stability.     

Does footwear affect articular cartilage volume change after a prolonged run?

The aim of this study was to investigate knee intra-articular cartilage volume changes after a prolonged running bout in three footwear conditions. Twelve participants performed 75-minute running bouts in the three footwear conditions. Before and after each running bout, magnetic resonance imaging (MRI) scans were obtained using a high-resolution 3.0 Tesla MRI. Three-dimensional reconstruction of the cartilage plates of the patella, the femur, and the tibia was created to quantify cartilage volume change due to the 75-minute running bout. Three-dimensional biomechanical data were also collected using an integrated motion capture and force treadmill system. There were no statistically significant differences among shoe conditions for all anatomical regions. However, significant cartilage volume reductions at all anatomical sites were observed after the 75-minute running bout in each footwear condition. These data suggest that the intra-articular knee cartilage undergoes a significant reduction in cartilage volume during a prolonged run that may indicate an increase in joint loading. There was a considerable variation in cartilage volume between participants across footwear conditions indicating an individual cartilage volume response to footwear. An individualistic approach to footwear recommendations may help in minimizing this change in cartilage.     

Biomechanics of graded running: Part II—Joint kinematics and kinetics

Compared to level running (LR), different strategies might be implemented by runners to cope with specific challenges of graded running at different speeds. The changes in joint kinetics and kinematics associated with graded running have been investigated, but their interactions with speed are unknown. Nineteen participants ran on an instrumented treadmill at five grades (0°, ±5° and ± 10°) and three speeds (2.50, 3.33 and 4.17 m/s), while 3D motion and forces were recorded. Three speed × five-grade repeated-measures ANOVA was used to analyze kinetic and kinematic variables. A speed × grade interaction was observed for hip range of motion (ROM). Downhill running (DR) at fastest speed did not reduce ROM at the hip, compared to LR. Compared to LR, it was observed that the hip joint was responsible for a greater contribution of energy generation while running at the fastest speed at +10°. Speed × grade interactions were also observed for the energy absorption, peak moment, and peak power at the knee. Contrary to LR, running faster during UR did not require higher peak power at the knee. Finally, DR at the fastest speed did not increase peak negative power at the knee compared to LR. This study demonstrates that ankle, knee, and hip joint kinetics depend on speed and grade of running, while the effect of grade on joint kinematics was not substantially modulated by speed.     

不同视觉方式引导下的运动想象脑电信号特征对比分析研究

目的 研究人服匹配因素（包括肘关节旋转中心位置、人服几何匹配度）对人服典型关节耦合运动的影响,了解人服耦合力学特性。方法 采用内置式测量方法进行试验,受试者穿戴航天服上肢组件在负压舱内指定位置完成肘关节屈曲运动,使用惯性运动捕捉系统与压力测量系统,分别采集人体运动数据与人服接触力的数据,并对测量结果进行分析。结果 人服耦合运动受到人服匹配因素的影响,受试者在4个位置肘关节屈曲40°时的平均力矩分别为3.7565Nm、2.8561Nm、2.9113Nm和4.0129Nm,屈曲过程消耗的能量平均为1.769J、1.565J、1.176J和1.982J;航天服关节阻尼力矩与围度比线性相关,相关系数r=0.7315。结论 航天服关节中间位置与人体肘关节旋转中心匹配时活动性能较好,较小的前臂围着服工况运动时受到的关节阻尼力矩较小,人服耦合力学特性与人服匹配因素密切相关。     

Reconstruction of the temporomandibular joint: a comparison between prefabricated and customized alloplastic prosthetic total joint systems

The implantation of an alloplastic total temporomandibular joint (TMJ) prosthesis is an innovative approach for the treatment of end-stage TMJ disorders. Two types of system exist: prefabricated (stock) and customized computer-aided design/computer-aided manufacturing (CAD/CAM) devices. A clinical study was performed to evaluate the effectiveness of these two designs. Twenty-eight patients treated between 2015 and 2017 were included and assigned to two groups: stock prostheses (group 1) and customized CAD/CAM prostheses (group 2). Clinical evaluations were performed at five time-points up to 6 months postoperative. Parameters included maximum interincisal opening, pain, diet, complications, and subjective well-being at the end of follow-up. Differences between pre-surgery and 6-month post-surgery values were highly significant (P < 0.001). No patient required a liquid diet at the end of treatment, and 66% of group 1 patients and 100% of group 2 patients reported improved well-being. Complications were observed in 32% of patients and included temporary paralysis of the facial nerve. In conclusion, clinical outcomes of stock and CAD/CAM prostheses suggested great improvements in mouth opening and reduction of pain as a result of the rehabilitation of TMJ function. Results showed comparable data for the two types of prosthesis design at 6 months postoperative.