全膝关节置换术后早期股四头肌肌力降低——肌肉主动激活障碍和肌萎缩

背景：尽管全膝关节置换能够缓解疼痛和恢复膝关节的功能活动度，但术后1年仍然存在股四头肌乏力和功能下降。本研究的目的是确定肌肉主动激活障碍和肌萎缩在术后早期股四头肌肌力降低中的作用。 方法：以20例单侧膝关节骨性关节炎患者分别在术前（平均10天）和术后（平均27天）进行测量。股四头肌肌力和主动激活通过脉冲叠加刺激技术测量，即在股四头肌最大主动等长收缩时给予一超阈值电流脉冲刺激。使用核磁共振成像技术测量股四头肌的最大横截面积。 结果：和术前相比，术后股四头肌肌力下降了62％，主动激活能力下降了17％，最大横截面积下降了10％，差异具有统计学意义（p〈0．01）。总的来说，股四头肌主动激活障碍和肌萎缩占股四头肌肌力下降原因的85％（p〈0．001）。多元线性回归分析发现股四头肌主动激活障碍导致的肌力丢失几乎是由于肌萎缩导致的肌力丢失的两倍。和术前水平相比，肌肉收缩时膝关节的疼痛程度在术后并没有显著变化（p=0．31）。在肌力测试中，膝关节疼痛的变化对于股四头肌主动激活没有显著的影响（p=0．14）。 结论：全膝关节置换术后1个月股四头肌肌力障碍仍然严重。这种肌力障碍主要由股四头肌的主动激活障碍引起，另外，肌萎缩也起到一定的作用。肌肉收缩时膝关节疼痛对肌肉主动激活的影响不大。可信水平：预测性研究，Ⅰ级。进一步可信度参见作者介绍。     

Lack of increased bleeding after paracentesis and thoracentesis in patients with mild coagulation abnormalities

To determine whether untreated mild coagulopathy in patients with no evidence of clinical bleeding is associated with an increased risk of hemorrhage after paracentesis or thoracentesis, retrospective examination was conducted of 608 consecutive procedures for which prothrombin time (PT), partial thromboplastin time (PTT), platelet (Plt) counts, and preprocedure and postprocedure hemoglobin concentrations were available. There was no increased bleeding in patients with mild to moderate coagulopathy (defined as PT or PTT up to twice the midpoint normal range or pit count of 50 to 99 x 10(3) per microL [50-99 x 10(9)/L]). However, patients with markedly elevated serum creatinine levels (6.0 to 14.0 mg/dL [530-1240 mumol/L]) had a significantly greater average hemoglobin loss (-0.82 +/- 1.3 g/dL [-8 +/- 13 g/L], n = 11) than patients with normal serum creatinine levels (-0.12 +/- 0.88 g/dL [-1 +/- 9 g/L], n = 450) (p = 0.011). Overall, the frequency of bleeding complications requiring red cell transfusions was very low: 0.2 percent of events. The most common diagnosis for patients who had paracentesis was alcoholic liver disease (72%); for those having thoracentesis, it was infection (37%). It can be concluded that, for these patients, prophylactic plasma or platelet transfusions are not necessary. Patients with markedly elevated serum creatinine deserve close postprocedure observation.     

Auswirkungen des ?Slacklinings“ auf die Gleichgewichtsf?higkeit von Senioren

Background

Staying independent and active in old age requires the ability to maintain equilibrium in the best possible way. Because of an increasing life expectancy physical fitness in the elderly is gaining more and more attention. The purpose of this randomized controlled trial was to examine whether slackline training for 3?weeks is suited to improve balance control in elderly people aged 60 years and over.

Methods

Thirty-four seniors aged 60?C72 years participated in this study. The participants were randomly assigned to an intervention group (n=17) or a control group (n=17). Subjects in the intervention group participated over a period of 3?weeks twice a week for 20?min in slackline training whereas control group subjects got no training. Baseline and post-intervention measurements included two clinical (functional reach test and balance test according to Wydra) and two biomechanical (posturography on a force platform and the BalensoSenso system) assessments to evaluate dynamic and static equilibration.

Results

Subjects who performed slackline training showed highly significant improvement in maintaining equilibrium under dynamic circumstances. Intervention group subjects also showed highly significant progression in static balance in the balance test according to Wydra and significantly reduced the length of sway in narrow stance on the force platform. All other measurements under static conditions showed no significant rise but tendencies of improvement were recorded. The control group demonstrated no significant changes in the post-measurement at all.

Conclusion

The results suggest that slackline training seems to be suited to improve equilibration in elderly people within a very short period of time.     

Treatment of lateral ankle instability with transfer of the extensor digitorum brevis muscle

Ankle sprains are the most common injuries sustained during sports and physical exercise. Treatment is usually conservative because most of these injuries heal without consequence. However, some injuries may be followed by chronic lateral pain and instability, and surgical stabilization is sometimes necessary. In select cases, there is little or no residual ligament or scar tissue remaining for late reconstruction. Proximal transfer of the origin of the extensor digitorum brevis muscle as a substitute for deficient ligament tissue can be used in these difficult cases. During the years 1971 to 1992, 13 ankles in 10 patients underwent surgery using the proximal extensor digitorum brevis muscle transfer method. At follow-up, all the ankles manifested functional stability and were stable with no clinical drawer sign. All had a normal range of motion in the ankle joint but showed a desired decreased supination range of motion throughout the hindfoot and ankle. The functional Karlsson scores were 84.5 +/- 18.8 before injury, 26.4 +/- 18.7 before surgery, and 83.6 +/- 18.7 at follow-up. Thus, the extensor digitorum brevis muscle transfer seems to be a useful alternative method of long-term ankle stabilization in these difficult chronic case; the results correlate well with a few other studies using this method.     

Predicting mortality and length-of-stay for neonatal admissions to private hospital neonatal intensive care units: a Southern African retrospective study

Objectives

To predict neonatal mortality and length of stay (LOS) from readily available perinatal data for neonatal intensive care unit (NICU) admissions in Southern African private hospitals.

Methods

Retrospective observational study using perinatal data from a large multicentre sample. Fifteen participating NICU centres in the Medi-Clinic private hospital group in Southern Africa. We used 2376 infants born between 1 January – 31 December 2008 to build the regression models, and a further 1 578 infants born between 1 January – 31 December 2007 to test the models. Outcome measures were mortality and length of hospital stay for NICU admissions.

Results

Of the infants included in the 2008 dataset, ninety-one (3.8%) died after being admitted to NICU centres. The median LOS for non-transferred survivors was 11 days. An analysis of the structural peculiarities of the data showed high correlations between groups of the perinatal variables pertaining to the size and Apgar scores of the newborn infants, respectively. The logistic regression model to predict neonatal mortality had a good fit (AUC: 0.8507, misclassification rate: 13.6%), but the low positive predictive value of this model reduces its usefulness. The poisson log-linear model to predict LOS had a good fit (predicted R²: 0.7027).

Conclusions

Apgar score at one minute, birth weight, and delivery mode significantly influence the odds of neonatal death and are associated with significant effects on LOS.     

The muscle activation of the erector spinae during hyperextension with and without the pelvis restrained

The purpose of this study was to determine if pelvic restraint during hyperextension on a variable angle Roman chair (VARC) changes the muscle activation of the erector spinae musculature. Seventy volunteers (18–35 years) performed hyperextension exercises on the VARC with and without the pelvis restrained. Surface electromyography (EMG) was used to measure the muscle activation of the erector spinae at the third lumbar vertebra (L3). Total root mean square (RMS) for eccentric and concentric phases were amplitude normalized to a maximal voluntary isometric contraction (MVIC). A post test questionnaire was used to determine the subjective feeling of localized fatigue.The EMG data were analyzed with a Multivariate Hotelling's T² test and univariatet -tests. The questionnaire data were analyzed using McNemar's test. Alpha was set at 0·05. A statistically significant (p < 0·01) but small (approximately 3%) increase in the RMS of the erector spinae was demonstrated in the unrestrained condition for both independent variables: concentric and eccentric motion. Conversely, a greater proportion of participants subjectively reported greater effort in the lumbar extensors with the pelvis restrained. It is unclear if these observed changes in muscle activation and subjective perceptions can direct changes in the clinical practice.     

Ergonomics in Industrialized Dairy Operations

ABSTRACT

This paper presents a summary of a panel presentation by agriculture health and safety scientists on ergonomics of industrialized dairy parlor operations in the United States. Dairy industry trends in the United States were discussed in the panel presentation, which took place during the New Paths: Health and Safety in Western Agriculture conference, November 11–13, 2008. Dairy production is steadily moving to large-herd operations because of associated economies of scale and other economic and social conditions. Large-herd operations utilize a parlor milking system, as compared to a stanchion system used primarily in smaller operations. Each milking system presents different risks for worker injury. Low back, knee, and shoulder musculoskeletal symptoms were most frequently reported among workers in smaller dairy operations. Another study analyzing workers' compensation (WC) data from large-herd milking operations found nearly 50% of livestock-handling injury claims involved parlor milking activities. Nearly 27% of injuries were to the wrist, hand, and fingers, nearly 13% to the head or face, and 11% to the chest. Results indicated the vulnerability of these body parts to injury due to the worker-livestock interface during milking. More focused research should investigate milking practices and parlor designs as they relate to worker safety and health. Additional dairy-related injury research is vital given the trend towards large industrial milking operations.     

Estimating within‐study covariances in multivariate meta‐analysis with multiple outcomes

Multivariate meta‐analysis allows the joint synthesis of effect estimates based on multiple outcomes from multiple studies, accounting for the potential correlations among them. However, standard methods for multivariate meta‐analysis for multiple outcomes are restricted to problems where the within‐study correlation is known or where individual participant data are available. This paper proposes an approach to approximating the within‐study covariances based on information about likely correlations between underlying outcomes. We developed methods for both continuous and dichotomous data and for combinations of the two types. An application to a meta‐analysis of treatments for stroke illustrates the use of the approximated covariance in multivariate meta‐analysis with correlated outcomes. Copyright © 2012 John Wiley & Sons, Ltd.