Assessing hip abduction and adduction strength: can greater segmental fixation enhance the reproducibility?

OBJECTIVE: To improve the reproducibility of testing hip abduction and adduction using an isokinetic dynamometer by a novel testing protocol. DESIGN: Test-retest design. SETTING: Biodynamics laboratory. PARTICIPANTS: Fifteen healthy subjects (9 men, 6 women; age, 22.4+/-0.5 y) were recruited. INTERVENTIONS: Two setups were compared: the first according to manufacturer's guidelines (setup A) and the second a novel setup incorporating pelvic fixation (setup B). Setups A and B were performed in a random order. Both setups included the same battery of isokinetic (30 degrees/s, 60 degrees/s) and isometric tests, and were repeated 1 week later. MAIN OUTCOME MEASURES: The peak torque for each abduction and adduction exercise was noted and pelvic motion during testing was recorded. RESULTS: Setup B significantly (P<.05) reduced transverse pelvic rotation by between 7.5 degrees and 8.0 degrees dependent on test speed. Mean differences for reproducibility of peak torque, ranged from 0.8 to 11.7 Nm. The coefficients of repeatability of both setups were similar, ranging from 21.4 to 56.3 Nm across isokinetic exercises. A similar observation was noted for isometric exercises, with the differences between the coefficients of repeatability ranging from 18.6 to 40.0 Nm. CONCLUSIONS: Reducing pelvic rotation does not enhance reproducibility of the system and is not related to torque production. Further research is required to determine the optimal test setup.     

Does the orientation of the distal radioulnar joint influence the force in the joint and the tension in the interosseous membrane?

OBJECTIVE: To investigate the effect of change in the orientation of the distal radioulnar joint on the force in the joint and the strain in the interosseous membrane. DESIGN: Biomechanical study in fresh frozen cadavers. BACKGROUND: The articular surfaces of the distal radioulnar joint may be orientated in parallel with the long axis of the forearm (a Type I joint) or at an oblique angle opening distally to the ulnar side (a Type II joint). METHODS: Three cadaveric upper limbs were held on a custom built frame allowing measured rotation and axial loading across the wrist. Measurements of force in the distal radioulnar joint and strain in the interosseous membrane were taken and repeated after replacement of the distal radioulnar joint with prosthetic Type I and Type II joints. FINDINGS: The force in the joint and the strain in the interosseous membrane increased with increasing load across the wrist (P < 0.0001). The force in the Type I joint was reduced compared to the normal or Type II joint. This difference was greater with increasing load and was significant at 8 kg (P < 0.001). The strain in the interosseous membrane was maximal at neutral forearm rotation and decreased with increasing pronation and supination. INTERPRETATION: The force in the joint is greater with the Type II distal radioulnar joint. We believe this compressive force increases joint stability and this orientation of the articular surfaces should be considered in the design of a total distal radioulnar joint arthroplasty.     

Odontoid plate fixation without C1–C2 arthrodesis: Biomechanical testing of a novel surgical technique and comparison to the conventional screw fixation procedure

Background

Odontoid plate fixation without C1–C2 arthrodesis appears to be a practicable option for the management of odontoid fractures that are not amenable for conventional screw fixation. The purpose of this study was to measure the mechanical stability of odontoid plate fixation using a specially designed plate construct, and to compare the results to those after conventional screw fixation.

Methods

The second cervical vertebra was removed from twenty fresh human spinal columns. Stiffness and failure load of the intact odontoid were measured, and type II odontoid fractures were created. Afterward, the specimens were randomly assigned to one of the following four groups: Group I: plate-fixation; Group II: 2-AO-screw-fixation; Group III: 1-AO-screw-fixation; Group IV: Herbert-screw-fixation. In a second series, stiffness and failure load of the stabilized odontoid fractures were assessed for comparison and statistical analysis.

Findings

Group I showed a significantly higher mean failure load than the other groups. The mean failure load of Group I after fixation of the odontoid fracture was 86% of the mean failure load of the intact odontoid. Comparing Groups II, III and IV, there was no significant difference regarding the failure load. In these three groups the mean failure load after odontoid fixation was approximately 50% of the mean failure load of the intact odontoid.

Interpretation

Odontoid plate fixation as an alternative procedure in certain fracture patterns provided a significantly higher biomechanical stability than the technique of odontoid screw fixation. Using a specially designed plate construct, 86% of the original stability of the intact odontoid was restored.     

Gastrointestinal motility and glycemic control in diabetes: the chicken and the egg revisited?

Upper gastrointestinal dysfunction occurs frequently in diabetes and potentially contributes to both abdominal symptoms and impaired glycemic control; conversely, variations in blood glucose concentration reversibly affect gut motility in humans. In this issue of the JCI, Anitha et al. report apoptosis of rodent enteric neurons under hyperglycemic conditions, both in vitro and in vivo, associated with impaired PI3K activity and preventable by glial cell line-derived neurotrophic factor. These observations add to recent insights gained from animal models regarding the etiology of diabetic gastrointestinal dysfunction, but investigators must strive to translate animal data to human diabetes.     

Is MAST in the past? The pros and cons of MAST usage in the field

Initially, MAST was viewed as a panacea for hypovolemic trauma patients. Through decades of study, this has not panned out. However, MAST seems to stabilize and decrease bleeding in pelvic and long-bone fractures of the lower extremities. It also appears useful in anaphylaxis and in non-traumatic intra-abdominal hemorrhage. The suit has proven deleterious to trauma victims with moderate hypotension (systolic BP 50-90 mm Hg) who face only a short ride to a hospital, especially those with thoracic injuries. Its role in patients with severe hypotension or long prehospital transport times remains unclear. In severely hypotensive patients, the improvement in BP and oxygenation to the heart and brain may override any negative effects of continued hemorrhage. We must wait for further studies to resolve these issues.     

Research in public health and end-of-life care – Building on the past and developing the new

Introduction: Public health approaches offer the opportunity to move beyond clinical and health services approaches to end-of-life (EoL) care, to focus on whole populations, individuals and communities rather than patients and carers. They also allow concepts such as capacity, resilience, and wellbeing to come to the fore.

Methods: This paper, drawing on the experience of a diverse group of academics and practitioners from three countries in Europe, considers the research challenges related to examining new public health approaches to EoL care and how learning from more traditional or classic public health research can influence a future research agenda. Additional opportunities provided by the new public health approach to broaden learning and participation in research are considered.

Results: By bringing together strong traditional methods such as analysis of longitudinal population-level data with participatory approaches that draw on communities' experience and aspirations for care, the authors suggest that new and improved opportunities exist to evaluate the impact of participatory approaches.

Discussion: In conclusion, the paper urges researchers from classic and new public health to work in partnership to generate and respond to the emerging research agenda around new public health initiatives. There is much to be learned from both.     

Are both the sensory and the affective dimensions of pain encoded in the face?

The facial expression of pain plays a crucial role in pain communication and pain diagnostics. Despite its importance, it has remained unknown which dimensions of pain (sensory and/or affective) are encoded in the face. To answer this question, we used a well-established cognitive strategy (suggestions) to differentially modulate the sensory and affective dimensions of pain and investigate the effect of this manipulation on facial responses to experimental pain. Twenty-two subjects participated in the study. Their facial expressions, pain intensity, and unpleasantness ratings as well as skin conductance responses to tonic and phasic heat pain were assessed before and after suggestions directed toward increase in affective and sensory qualities of pain, respectively, were provided. Facial expressions were analyzed with the Facial Action Coding system. As expected, suggestions designed to increase the sensory dimension produced a selective increase in pain intensity ratings, whereas suggestions designed to increase pain affect produced increased unpleasantness ratings and elevated skin conductance responses. Furthermore, suggestions for either increased pain affect or pain sensation produced selective modulations in facial response patterns, with facial movements around the eyes mostly encoding sensory aspects, whereas movements of the eyebrows and of the upper lip were closely associated with the affective pain dimension. The facial expression of pain is a multidimensional response system that differentially encodes affective and sensory pain qualities. This differential encoding might have evolved to guarantee that the specific characteristics of one’s pain experience are facially communicated, thereby ensuring adequate help and support from others.