Discriminating Between Copers and those with Chronic Ankle Instability with Clinical Outcomes

Introduction: Chronic ankle instability (CAI) is a common consequence of lateral ankle sprains and a leading cause of post-traumatic ankle osteoarthritis. Despite a history of a lateral ankle sprain, there are some individuals (copers) who appear to have a mechanism that allows them to avoid recurrent lateral ankle sprains and giving way episodes. To date, research has identified differences in perceptual (e.g. self-assessed disability), mechanical (e.g. ligament laxity), and sensorimotor (e.g. balance) outcomes between copers and those with CAI. However, the vast majority of these outcomes are considered research and/or laboratory based and thus impractical for most clinicians to use on a daily basis. The identification of clinical tools, capable of discriminating between copers and those with CAI is the first step in developing an accurate clinical battery of tests that can be used to predict patients more likely to develop CAI after an initial lateral ankle sprain. Therefore, the purpose of this investigation was to establish the ability of clinical outcome measures to discriminate between copers and those with CAI. Methods: Participants- A total of 46 participants (21 copers and 25 with CAI) were enrolled and completed the investigation. All participants read and signed the university approved informed consent document prior to participation. All subjects were between the ages of 18-30 and participated in recreational activity for at least 90 minutes each week. Copers and those with CAI had a history of at least one moderate to severe ankle sprain that required acute care. Copers resumed all pre-injury activity without limitation and without recurrent episodes of injury/giving way for at least 12 months prior to testing and scored \u3e24 on the ankle joint functional assessment tool (AJFAT). In comparison, those with CAI had at least one recurrent sprain within 6 months of testing and scored \u3c20 on the AJFAT. Protocol: Perceptual outcomes, the Foot Ankle Ability Measure (FAAM) and FAAM Sport (FAAM-S) were completed first. These questionnaires determine a subject’s self-assessed limitations during daily and physical activities and lower scores represent greater disability. Next, mechanical adaptations were assessed via the the weight bearing lunge test (WBLT) and talar glide test. The WBLT measured ankle dorsiflexion range of motion using a modified lunge technique. Maximum dorsiflexion was defined as the furthest distance the subject’s foot could be from a wall while the subject’s knee was in contact with the wall and the subject’s heel was flat on the ground. The talar glide test measures the magnitude of the talus’ posterior glide by measuring the change in passive knee flexion, from 90°, while an examiner simultaneously pushes the talus posteriorly and pulls the foot into dorsiflexion until the point of capsular restriction. Finally, sensorimotor dysfunction was assessed with the Star Excursion Balance Test (SEBT) and isometric strength testing. The SEBT is a measure of dynamic postural control and measures the distance a subject can reach with their contralateral leg without losing their balance. Reach distance was defined as the farthest point that an individual could touch without accepting weight on their reach leg and maintaining balance through the return to a bilateral stance. Reach distance was normalized to each subject’s leg length. Using a handheld dynamometer, ankle dorsiflexion, plantar flexion, eversion, and inversion strength was assessed during 3-second maximal contractions. Strength was normalized to a subject’s body weight. Statistical Analysis: Group differences in perceptual, mechanical, and sensorimotor outcomes were assessed with independent sample t-tests. If significance was achieved, the ability of an outcome to accurately discriminate between the groups was then assessed using the area under the curve (AUC) for receiver operating characteristic (ROC) curves. A ROC curve illustrates the “trade-off” between sensitivity and specificity throughout a measure’s entire range of values. Finally, clinical meaningfulness was established by the calculation of cut-off scores and likelihood ratios for outcomes that successfully discriminated between copers and those with CAI. A traditional level of significance (=0.05) was used for all analyses. RESULTS: The CAI group had significant perceptual and sensorimotor deficits relative to the coper group. Specifically, FAAM (Coper: 99.0±2.5%, CAI: 89.2±9.5%), FAAM-S (Coper: 96.6±4.1%, CAI: 79.3±16.2%), normalized posteriomedial SEBT reach distance (Coper: 91.2±8.1%, CAI: 83.5±6.5%), and normalized dorsiflexion strength (Coper: 74.5±19.9%, CAI: 62.9±12.8%) were lower in those with CAI relative to copers. The secondary analysis revealed that the FAAM (P\u3c0.01), FAAM-S (p\u3c0.01), and posteriomedial SEBT reach distance (p\u3c0.01) accurately discriminated between copers and those with CAI. The AUC scores, cut-off scores, and likelihood ratios can be seen in the table below. No differences existed with regards to talar glide, range of motion, anterior SEBT reach, posteriolateral SEBT reach, and normalized eversion, inversion, or plantar flexion strength. Outcome Measure Category AUC Cut-off Score Likelihood Ratios (95% Confidence Intervals) Positive Negative FAAM 0.93 99% 5.05 (2.92 to 10.36) 0.05 (0.01 to 0.21) FAAM-S 0.90 88% 31.00 (4.42 to 217.67) 0.33 (0.22 to 0.51) Posteriomedial SEBT Reach 0.79 89% 2.53 (1.77 to 3.79) 0.06 (0.02 to 0.27) DISCUSSION: The results of this investigation indicate that perceptual (FAAM, FAAM-S) and some sensorimotor outcomes (posteriomedial SEBT reach distance) can discriminate between copers and those with CAI. We hypothesize that these outcome measures represent part of the mechanism that 1) allows copers to function as if uninjured and 2) is absent in individuals who develop CAI. The current results, using clinical outcome measures, support previous findings that have illustrated perceptual and sensorimotor deficits using research and/or laboratory based outcomes. Further, because a variety of the current outcomes (perceptual and sensorimotor) successfully discriminated between copers and those with CAI, groups, the current findings support the theory that the causal mechanism of CAI is multi-factorial in nature. However, the most important finding of the current investigation is that the perceptual outcomes demonstrated the greatest ability to discriminate between copers and those with CAI with accuracy point estimates ranging from 0.90-0.93. Indeed, the perceptual outcomes (as a whole) demonstrated higher AUC estimates and positive likelihood ratios, as well as lower negative likelihood ratios compared with the sensorimotor outcomes (as a whole). This finding, which supports previous results, indicates that perceptual outcomes have the greatest ability to accurately predict those who became copers after initial lateral ankle sprain. Given the magnitude of the positive and negative likelihood ratios, we believe that perception based outcomes, such as the FAAM and FAAM-S, should be used in future longitudinal research investigations designed to determine if and when, post-injury, these outcomes can predict who will develop CAI after an initial lateral ankle sprain

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Mitochondrial precursor proteins are imported through a hydrophilic membrane environment

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Young people, crime and school exclusion: a case of some surprises

During the 1990s the number of young people being permanently excluded from schools in England and Wales increased dramatically from 2,910 (1990/91) to a peak of 12,700 (1996/97). Coinciding with this rise was a resurgence of the debate centring on lawless and delinquent youth. With the publication of Young People and Crime (Graham and Bowling 1995) and Misspent Youth (Audit Commission 1996) the 'common sense assumption' that exclusion from school inexorably promoted crime received wide support, with the school excludee portrayed as another latter day 'folk devil'. This article explores the link between school exclusion and juvenile crime, and offers some key findings from a research study undertaken with 56 young people who had experience of being excluded from school. Self-report interview questions reveal that whilst 40 of the young people had offended, 90% (36) reported that the onset of their offending commenced prior to their first exclusion. Moreover, 50 (89.2% of the total number of young people in the sample), stated that they were no more likely to offend subsequent to being excluded and 31 (55.4%) stated that they were less likely to offend during their exclusion period. Often, this was because on being excluded, they were 'grounded' by their parents

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Annihilation vs. Decay: Constraining dark matter properties from a gamma-ray detection

Most proposed dark matter candidates are stable and are produced thermally in the early Universe. However, there is also the possibility of unstable (but long-lived) dark matter, produced thermally or otherwise. We propose a strategy to distinguish between dark matter annihilation and/or decay in the case that a clear signal is detected in gamma-ray observations of Milky Way dwarf spheroidal galaxies with gamma-ray experiments. The sole measurement of the energy spectrum of an indirect signal would render the discrimination between these cases impossible. We show that by examining the dependence of the intensity and energy spectrum on the angular distribution of the emission, the origin could be identified as decay, annihilation, or both. In addition, once the type of signal is established, we show how these measurements could help to extract information about the dark matter properties, including mass, annihilation cross section, lifetime, dominant annihilation and decay channels, and the presence of substructure. Although an application of the approach presented here would likely be feasible with current experiments only for very optimistic dark matter scenarios, the improved sensitivity of upcoming experiments could enable this technique to be used to study a wider range of dark matter models.Comment: 29 pp, 8 figs; replaced to match published version (minor changes and some new references

Sensory-Targeted Ankle Rehabilitation Strategies for Chronic Ankle Instability

Deficient sensory input from damaged ankle ligament receptors is thought to contribute to sensorimotor deficits in those with chronic ankle instability (CAI). Targeting other viable sensory receptors may then enhance sensorimotor control in these patients. The purpose of this randomized controlled trial was to evaluate the effects of 2 weeks of sensory-targeted rehabilitation strategies (STARS) on patient- and clinician-oriented outcomes in those with CAI

Predicting Manual Therapy Treatment Success in Patients With Chronic Ankle Instability: Improving Self-Reported Function

CONTEXT: Therapeutic modalities that stimulate sensory receptors around the foot-ankle complex improve chronic ankle instability (CAI)-associated impairments. However, not all patients have equal responses to these modalities. Identifying predictors of treatment success could improve clinician efficiency when treating patients with CAI. OBJECTIVE: To conduct a response analysis on existing data to identify predictors of improved self-reported function in patients with CAI. DESIGN: Secondary analysis of a randomized controlled clinical trial. SETTING: Sports medicine research laboratories. PATIENTS OR OTHER PARTICIPANTS: Fifty-nine patients with CAI, which was defined in accordance with the International Ankle Consortium recommendations. INTERVENTION(S): Participants were randomized into 3 treatment groups (plantar massage [PM], ankle-joint mobilization [AJM], or calf stretching [CS]) that received six 5-minute treatments over 2 weeks. MAIN OUTCOME MEASURE(S): Treatment success, defined as a patient exceeding the minimally clinically important difference of the Foot and Ankle Ability Measure-Sport (FAAM-S). RESULTS: Patients with ≤5 recurrent sprains and ≤82.73% on the Foot and Ankle Ability Measure had a 98% probability of having a meaningful FAAM-S improvement after AJM. As well, ≥5 balance errors demonstrated 98% probability of meaningful FAAM-S improvements from AJM. Patients <22 years old and with ≤9.9 cm of dorsiflexion had a 99% probability of a meaningful FAAM-S improvement after PM. Also, those who made ≥2 single-limb-stance errors had a 98% probability of a meaningful FAAM-S improvement from PM. Patients with ≤53.1% on the FAAM-S had an 83% probability of a meaningful FAAM-S improvement after CS. CONCLUSIONS: Each sensory-targeted ankle-rehabilitation strategy resulted in a unique combination of predictors of success for patients with CAI. Specific indicators of success with AJM were deficits in self-reported function, single-limb balance, and <5 previous sprains. Age, weight-bearing-dorsiflexion restrictions, and single-limb balance deficits identified patients with CAI who will respond well to PM. Assessing self-reported sport-related function can identify CAI patients who will respond positively to CS