Preparatory co-activation of the ankle muscles may prevent ankle inversion injuries

Ankle inversion sprains are the most frequent acute musculoskeletal injuries occurring in physical activity. Interventions that retrain muscle coordination have helped rehabilitate injured ankles, but it is unclear which muscle coordination strategies, if any, can prevent ankle sprains. The purpose of this study was to determine whether coordinated activity of the ankle muscles could prevent excessive ankle inversion during a simulated landing on a 30° incline. We used a set of musculoskeletal simulations to evaluate the efficacy of two strategies for coordinating the ankle evertor and invertor muscles during simulated landing scenarios: planned co-activation and stretch reflex activation with physiologic latency (60-ms delay). A full-body musculoskeletal model of landing was used to generate simulations of a subject dropping onto an inclined surface with each coordination condition. Within each condition, the intensity of evertor and invertor co-activity or stretch reflexes were varied systematically. The simulations revealed that strong preparatory co-activation of the ankle evertors and invertors prior to ground contact prevented ankle inversion from exceeding injury thresholds by rapidly generating eversion moments after initial contact. Conversely, stretch reflexes were too slow to generate eversion moments before the simulations reached the threshold for inversion injury. These results suggest that training interventions to protect the ankle should focus on stiffening the ankle with muscle co-activation prior to landing. The musculoskeletal models, controllers, software, and simulation results are freely available online at http://simtk.org/home/ankle-sprains, enabling others to reproduce the results and explore new injury scenarios and interventions.     

Rationalising requests for x-ray examination of acute ankle injuries.

Radiographs of injured ankles represent about 1 in 50 of all radiological examinations. The notes and radiographs of 100 patients with ankle injuries were reviewed, and the films of a further 93 patients who had ankle fractures treated by immobilisation were also scrutinised to assess the presence of absence of soft tissue swelling over the malleoli. Any accompanying radiographs of the foot requested at the same time were also studied. In 65 of the 100 cases of ankle injury there was no soft tissue swelling, and none of the patients had a major fracture, while 92 of the 93 patients with a major fracture had soft tissue swelling at the level of the malleoli. In 32 of the 100 cases of ankle injury foot radiographs had also been requested, but only three foot injuries were found. If the simple maxim of "No swelling adjacent to a malleolus, no radiographs" were applied radiography of twisted ankles could be reduced by as much as two-thirds. Moreover, if this maxim included the rider "and no routine foot films" the total casualty radiographic work load could be reduced by 8%.     

Differentiation of ankle sprain motion and common sporting motion by ankle inversion velocity

This study investigated the ankle inversion and inversion velocity between various common motions in sports and simulated sprain motion, in order to provide a threshold for ankle sprain risk identification. The experiment was composed of two parts: Firstly, ten male subjects wore a pair of sport shoes and performed ten trials of running, cutting, jump-landing and stepping-down motions. Secondly, five subjects performed five trials of simulated sprain motion by a supination sprain simulator. The motions were analyzed by an eight-camera motion capture system at 120 Hz. A force plate was employed to record the vertical ground reaction force and locate the foot strike time for common sporting motions. Ankle inversion and inversion velocity were calculated by a standard lower extremity biomechanics calculation procedure. Profiles of vertical ground reaction force, ankle inversion angle and ankle inversion velocity were obtained. Results suggested that the ankle was kept in an everted position during the stance. The maximum ankle inversion velocity ranged from 22.5 to 85.1°/s and 114.0 to 202.5°/s for the four tested motions and simulated sprain motion respectively. Together with the ankle inversion velocity reported in the injury case (623°/s), a threshold of ankle inversion velocity of 300°/s was suggested for the identification of ankle sprain. The information obtained in this study can serve as a basis for the development of an active protection apparatus for reducing ankle sprain injury.     

Effects of fatigue and gender on peroneal reflexes elicited by sudden ankle inversion.

The purpose of this study was to investigate the effects of neuromuscular fatigue and gender on peroneus brevis muscle (PB) and peroneus longus muscle (PL) reflexes elicited by sudden ankle inversion. Sixteen males and fifteen females stood on a "trap-door" platform that suddenly inverted the ankle 20 degrees when released. The resulting movement elicited peroneal reflexes. Reflex measurements were collected both before and after fatiguing the ankle evertors. Reflex delay in the PB and PL was not affected by fatigue, gender, or their interaction. Reflex amplitude in the PL exhibited no main effect of fatigue or gender, but their interaction was significant. Pairwise comparisons revealed PL reflex amplitude decreased by 11.3% in males (p=0.008) and increased 22.1% in females (p=0.003) with fatigue. A similar trend was found in the PB, but was not statistically significant. This opposite effect in females and males may be due to differences in how males and females compensate for fatigue, and may be related to the gender difference in ankle injury rate.     

Spiral computed tomography in the diagnosis of ankle and foot injuries

The data on 187 patients with traumatic lesions of the ankle joint and foot were used to analyze the capacities of computed tomography (CT) in the diagnosis of this pathology. The efficiency of CT versus X-ray study was evaluated. Specific guidelines are given to make spital CT. CT is shown to be of the most informative value in the diagnosis of lesions of the tibial plateau, undisplaced fractures of the internal malleolus, small marginal comminuted fractures, and lesions of the distal tibiofibular syndesmosis. There is evidence for that CT plays a dominant role in the diagnosis of lesions of the talus and calcaneus. Emphasis is laid on the great value of secondary multi- and three-dimensional image reconstructions.     

Guidelines for drug donations.

Drug donations are usually given in response to acute emergencies, but they can also be part of development aid. Donations may be given directly by governments, by non-governmental organisations, as corporate donations (direct or through private voluntary organisations), or as private donations to single health facilities. Although there are legitimate differences between these donations, basic rules should apply to them all. This common core of "good donation practice" is the basis for new guidelines which have recently been issued by the World Health Organisation after consultation with all relevant United Nations agencies, the Red Cross, and other major international agencies active in humanitarian emergency relief. This article summarises the need for such guidelines, the development process, the core principles, and the guidelines themselves and gives practical advice to recipients and donor agencies.     

The principles of radiological quality assessment of water resources

In the paper the main approaches to radiation safety of water objects have been analyzed. It is shown that radiation safety requirements for drinking water, fixed in the Rules and Regulations on radiation safety, do not ensure radiation safety of water objects used for the complex national economy needs. Application of the conservatism principle (choosing of the worst variant) for radiation safety ensuring is considered and proved. On the base of this principle the model is developed comparing the anthropocentric (sanitary--hygienic) with ecological (biota) principles for ensuring safety of water objects. It is proved, that the application of the Water Radiation Safety Rules currently in force, based on the norms of dose quotas, reserved for regulation of nuclear power plants and industry impact, ensures safety of the water ecological systems.     

An assessment of three selective media for bifidobacteria in faeces

Three previously described media enumerating Bifidobacterium spp. in faeces were compared with respect to their selectivity and quantitative recovery. The results of this study indicate that of the three media studied, Beerens'agar is the most suitable medium for isolation and enumeration of Bifidobacterium spp. from the gut microflora.