Development and external validation of a prediction model for patient-relevant outcomes in patients with chronic widespread pain and fibromyalgia.

BACKGROUND: The objective of this study was to develop prediction models and explore the external validity of the models in a large sample of patients with chronic widespread pain (CWP) and fibromyalgia (FM). METHODS: Patients with CWP and FM referred to rehabilitation services in Norway (n = 986) self-reported data on potential predictors prior to entering rehabilitation, and self-reported outcomes at one-year follow-up. Logistic regression models of improvement, worsening and work status, and a linear regression model of health-related quality of life (HRQoL), were developed using lasso regression. Externally validated estimates of model performance were obtained from the validation set. RESULTS: The number of participants in the development and the validation sets was 771 and 215 respectively; only participants with outcome data (n = 519-532 and 185, respectively) were included in the analyses. On average, HRQoL and work status changed little over one year. The prediction models included 10-11 predictors. Discrimination (AUC statistic) for prediction of outcome at follow-up was 0.71 for improvement, 0.67 for worsening, and 0.87 for working. The median absolute error of predictions of HRQoL was 0.36 (0.22-0.51). Reasonably good predictions of working at follow-up and HRQoL could be obtained using only the baseline scores as predictors. CONCLUSIONS: Moderately complex prediction models (10-11 predictors) generated poor to excellent predictions of patient-relevant outcomes. Simple prediction models of working and HRQoL at follow-up may be nearly as accurate and more practical. SIGNIFICANCE: Prediction modelling of outcome in rehabilitation has been sparsely explored. Such models may guide clinical decision-making. This study developed and externally validated prediction models for outcomes of people with chronic widespread pain and fibromyalgia in a rehabilitation setting. Multivariable prediction models generated poor to excellent predictions of patient-relevant outcomes, but the complexity of these models may reduce their clinical utility. Simple univariable prediction models were nearly as accurate and may have more potential for use in clinical practice.

Prevalence of motor impairment in residents of New South Wales, Australia aged 55 years and over: cross-sectional survey of the 45 and Up cohort.

BACKGROUND: The population prevalence of many diseases is known. However, little is known of the population prevalence of motor impairments. METHODS: The aim of this study was to determine the point prevalence of specific motor impairments (weakness, fatigue, contracture, impaired balance and impaired coordination) in the population aged 55 years and older resident in New South Wales, Australia in 2018. 55,210 members of the 45 and Up cohort were invited to participate in a follow-up survey that included questions on motor impairment. Responses were received from 20,141 people (36%). Calibrated estimates of prevalence of specific motor impairments, and of having at least one motor impairment, were obtained using survey weights based on the known multivariate distributions of age, gender and geographical location (28 regions) in the population. RESULTS: More than one-third of adults aged over 55 residing in New South Wales have difficulty using their hands, arms or legs. The prevalence of each motor impairment (muscle weakness, fatigue, contracture, impaired balance or impaired coordination) in this population is between 4 and 12%. The prevalence of at least one of these impairments is 21%. The prevalence of at least one impairment in people aged 85 and over is 42%. Women consistently had more difficulty using hands, arms and legs, and more motor impairment, than men. Difficulty using hands, arms and legs and the prevalence of all motor impairments, especially poor balance, greatly increased with age. CONCLUSION: The prevalence of specific motor impairments in older Australian adults is high - comparable to that of the most prevalent diseases. There may be merit in considering motor impairment as a significant public health problem in its own right.

Passive changes in muscle length.

This review, the first in a series of minireviews on the passive mechanical properties of skeletal muscles, seeks to summarize what is known about the muscle deformations that allow relaxed muscles to lengthen and shorten. Most obviously, when a muscle lengthens, muscle fascicles elongate, but this is not the only mechanism by which muscles change their length. In pennate muscles, elongation of muscle fascicles is accompanied by changes in pennation and changes in fascicle curvature, both of which may contribute to changes in muscle length. The contributions of these mechanisms to change in muscle length are usually small under passive conditions. In very pennate muscles with long aponeuroses, fascicle shear could contribute substantially to changes in muscle length. Tendons experience moderate axial strains even under passive loads, and, because tendons are often much longer than muscle fibers, even moderate tendon strains may contribute substantially to changes in muscle length. Data obtained with new imaging techniques suggest that muscle fascicle and aponeurosis strains are highly nonuniform, but this is yet to be confirmed. The development, validation, and interpretation of continuum muscle models informed by rigorous measurements of muscle architecture and material properties should provide further insights into the mechanisms that allow relaxed muscles to lengthen and shorten.

A simple but reliable method for measuring 3D Achilles tendon moment arm geometry from a single, static magnetic resonance scan.

Current methods for measuring in vivo 3D muscle-tendon moment arms generally rely on the acquisition of magnetic resonance imaging (MRI) scans at multiple joint angles. However, for patients with musculoskeletal pathologies such as fixed contractures, moving a joint through its full range of motion is not always feasible. The purpose of this research was to develop a simple, but reliable in vivo 3D Achilles tendon moment arm (ATMA) technique from a single static MRI scan. To accomplish this, for nine healthy adults (5 males, 4 females), the geometry of a cylinder was fit to the 3D form of the talus dome, which was used to estimate the talocrural flexion/extension axis, and a fifth-order polynomial fit to the line of action of the Achilles tendon. The single static scan in vivo 3D ATMA estimates were compared to estimates obtained from the same subjects at the same ankle joint angles using a previously validated 3D dynamic MRI based in vivo ATMA measurement technique. The ATMA estimates from the single scan in vivo 3D method (52.5mm±5.6) were in excellent agreement (ICC=0.912) to the validated in vivo 3D method (51.5mm±5.1). These data show reliable in vivo 3D ATMA can be obtained from a single MRI scan for healthy adult populations. The single scan, in vivo 3D ATMA technique provides researchers with a simple, but reliable method for obtaining subject-specific ATMAs for musculoskeletal modelling purposes.

A pilot randomised trial of community-based care following discharge from hospital with a recent spinal cord injury in Bangladesh.

OBJECTIVES: To explore the feasibility of conducting a full trial designed to determine the effectiveness of a model of community-based care for people with spinal cord injury in Bangladesh. STUDY DESIGN: A pilot randomised trial. SETTING: Community, Bangladesh. SUBJECTS: Participants were 30 people with recent spinal cord injury who were wheelchair-dependent and soon to be discharged from hospital. INTERVENTION: Participants randomised to the intervention group received a package of care involving regular telephone contact and three home visits over two years. Participants randomised to the control group received usual care consisting of a telephone call and an optional home visit. MAIN MEASURES: Participants were assessed at baseline and two years after randomization. The primary outcome was mortality and secondary outcomes were measures of complications, depression, participation and quality of life. RESULTS: A total of 24 participants had a complete spinal cord injury and six participants had an incomplete spinal cord injury. Median (interquartile) age and time since injury at baseline were 31 years (24 to 36) and 7 months (4 to 13), respectively. Two participants, one in each group, died. Five participants had pressure ulcers at two years. There were no notable impediments to the conduct of the trial and no significant protocol violations. The phone calls and home visits were delivered according to the protocol 87% and 100% of the time, respectively. Follow-up data were 99% complete. CONCLUSION: This pilot trial demonstrates the feasibility of a full clinical trial of 410 participants, which has recently commenced. SPONSORSHIP: University of Sydney, Australia.

Psychological and socioeconomic status, complications and quality of life in people with spinal cord injuries after discharge from hospital in Bangladesh: a cohort study.

STUDY DESIGN: Mixed retrospective-prospective cohort study. OBJECTIVES: To determine psychological and socioeconomic status, complications and quality of life in people with spinal cord injuries (SCI) after discharge from a hospital in Bangladesh. SETTING: Bangladesh. METHODS: All patients admitted in 2011 with a recent SCI to a hospital in Bangladesh were identified. Patients were interviewed by telephone in 2014 using translated versions of the SF12, the SCI Secondary Conditions Scale, the Centre for Epidemiologic Studies Depression Scale (CESDS) and the Participation Component of the WHODAS. Questions were also asked about employment, living and financial situation, and opportunities to get out of bed and out of the house. Data were stratified by ability to walk on discharge. RESULTS: A total of 350 people were discharged with a recent SCI in 2011. By 2014, 55 had died. Of those still living, 283 were interviewed (96% follow-up rate). At the time of interview, 47% of participants were employed. One-quarter (26%) of those who were wheelchair-dependent had a pressure ulcer. The mean (s.d.) scores for the Mental and Physical Component of the SF12 were 32.0 points (5.5) and 35.8 points (3.9), respectively. The median (interquartile range) scores for the SCI Secondary Conditions Scale, CESDS and WHODAS for those who were wheelchair-dependent were 15% (10 to 19), 11 points (9 to 18) and 26 points (23 to 26), respectively. CONCLUSION: Many people with SCI in Bangladesh are house-bound, unemployed, living in poverty and have pressure ulcers. They experience moderate rates of depression and report limited quality of life.

Two-year survival following discharge from hospital after spinal cord injury in Bangladesh.

STUDY DESIGN: Mixed retrospective-prospective cohort study. OBJECTIVES: To determine 2-year survival following discharge from hospital after spinal cord injury in Bangladesh. SETTING: Bangladesh. METHODS: Medical records were used to identify all patients admitted in 2011 with a recent spinal cord injury to the Centre for Rehabilitation of the Paralysed, a large Bangladeshi hospital that specialises in care of people with spinal cord injury. Patients or their families were subsequently visited or contacted by telephone in 2014. Vital status and, where relevant, date and cause of death were determined by verbal autopsy. RESULTS: 350 of 371 people admitted with a recent spinal cord injury in 2011 were discharged alive from hospital. All but eleven were accounted for two years after discharge (97% follow-up). Two-year survival was 87% (95% CI 83% to 90%). Two-year survival of those who were wheelchair-dependent was 81% (95% CI 76% to 86%). The most common cause of death was sepsis due to pressure ulcers. CONCLUSION: In Bangladesh, approximately one in five people with spinal cord injury who are wheelchair-dependent die within two years of discharge from hospital. Most deaths are due to sepsis from potentially preventable pressure ulcers.

Changes in the length and three-dimensional orientation of muscle fascicles and aponeuroses with passive length changes in human gastrocnemius muscles.

The mechanisms by which skeletal muscles lengthen and shorten are potentially complex. When the relaxed human gastrocnemius muscle is at its shortest in vivo lengths it falls slack (i.e. it does not exert any passive tension). It has been hypothesised that when the muscle is passively lengthened, slack is progressively taken up, first in some muscle fascicles then in others. Two-dimensional imaging methods suggest that, once the slack is taken up, changes in muscle length are mediated primarily by changes in the lengths of the tendinous components of the muscle. The aims of this study were to test the hypothesis that there is progressive engagement of relaxed muscle fascicles, and to quantify changes in the length and three-dimensional orientation of muscle fascicles and tendinous structures during passive changes in muscle length. Ultrasound imaging was used to determine the location, in an ultrasound image plane, of the proximal and distal ends of muscle fascicles at 14 sites in the human gastrocnemius muscle as the ankle was rotated passively through its full range. A three-dimensional motion analysis system recorded the location and orientation of the ultrasound image plane and the leg. These data were used to generate dynamic three-dimensional reconstructions of the architecture of the muscle fascicles and aponeuroses. There was considerable variability in the measured muscle lengths at which the slack was taken up in individual muscle fascicles. However, that variability was not much greater than the error associated with the measurement procedure. An analysis of these data which took into account the possible correlations between errors showed that, contrary to our earlier hypothesis, muscle fascicles are not progressively engaged during passive lengthening of the human gastrocnemius. Instead, the slack is taken up nearly simultaneously in all muscle fascicles. Once the muscle is lengthened sufficiently to take up the slack, about half of the subsequent increase in muscle length is due to elongation of the tendinous structures and half is due to elongation of muscle fascicles, at least over the range of muscle-tendon lengths that was investigated (up to ∼60 or 70% of the range of in vivo lengths). Changes in the alignment of muscle fascicles and flattening of aponeuroses contribute little to the total change in muscle length.

A non-invasive, 3D, dynamic MRI method for measuring muscle moment arms in vivo: demonstration in the human ankle joint and Achilles tendon.

Muscle moment arms are used widely in biomechanical analyses. Often they are measured in 2D or at a series of static joint positions. In the present study we demonstrate a simple MRI method for measuring muscle moment arms dynamically in 3D from a single range-of-motion cycle. We demonstrate this method in the Achilles tendon for comparison with other methods, and validate the method using a custom apparatus. The method involves registration of high-resolution joint geometry from MRI scans of the stationary joint with low-resolution geometries from ultrafast MRI scans of the slowly moving joint. Tibio-talar helical axes and 3D Achilles tendon moment arms were calculated throughout passive rotation for 10 adult subjects, and compared with recently published data. A simple validation was conducted by comparing MRI measurements with direct physical measurements made on a phantom. The moment arms measured using our method and those of others were similar and there was good agreement between physical measurements (mean 41.0mm) and MRI measurements (mean 39.5mm) made on the phantom. This new method can accurately measure muscle moment arms from a single range-of-motion cycle without the need to control rotation rate or gate the scanning. Supplementary data includes custom software to assist implementation.

Predator-prey systems depend on a prey refuge.

Models of near-exclusive predator-prey systems such as that of the Canadian lynx and snowshoe hare have included factors such as a second prey species, a Holling Type II predator response and climatic or seasonal effects to reproduce sub-sets of six signature patterns in the empirical data. We present an agent-based model which does not require the factors or constraints of previous models to reproduce all six patterns in persistent populations. Our parsimonious model represents a generalised predator and prey species with a small prey refuge. The lack of the constraints of previous models, considered to be important for those models, casts doubt on the current hypothesised mechanisms of exclusive predator-prey systems. The implication for management of the lynx, a protected species, is that maintenance of an heterogeneous environment offering natural refuge areas for the hare is the most important factor for the conservation of this species.

Patterns of physical activity in children with haemophilia.

The current widespread use of prophylaxis in developed countries has enabled greater participation in physical activity. However, there are no data available on leisure-time physical activity in Australian children with haemophilia. The data reported here were obtained from a case-crossover study nested in a prospective cohort study of 104 boys with moderate and severe haemophilia followed for one year. Each child's physical activity was assessed using a modifiable physical activity questionnaire (Kriska's MAQ) administered at baseline, and a one-week prospective activity diary at a randomly determined time. Children were aged 4-18 years. The median time spent in sport or leisure-time physical activity in the preceding year was 7.9 h/week (IQR 4.6 to 12.9). The median time spent in vigorous physical activity was 3.8 h/week (IQR 1.6 to 6.4) and in moderate and vigorous physical activity 6.4 h/week (IQR 3.7 to 10.0). The median small-screen time was 2.5 h/day (IQR 0.5 to 2.5). Forty-five per cent of all children and 61% of children over the age of 10 years played at least one competitive sport. Averaged across one week, 43% of all children met the Australian government physical activity guidelines for children and 36% met the guidelines for small-screen time. This study provides the first data regarding leisure-time physical activity in children with haemophilia living in Australia. The majority of Australian children with haemophilia are not meeting the national physical activity and small-screen time guidelines.

Feasibility of short message service to document bleeding episodes in children with haemophilia.

The increasing emphasis on home-based treatment for the management of children with haemophilia has meant that many of these children no longer regularly report to a medical facility. Consequently, it is difficult to monitor incidence of bleeding episodes. The aim of this study was to assess the feasibility of using a short message service (SMS) to monitor incidence of bleeding episodes in children with haemophilia. One hundred and four children with moderate and severe haemophilia A or B took part in a 1-year prospective study between 2008 and 2010. Children or their parents were asked to maintain a bleeds diary. They received a weekly SMS asking whether there had been a bleeding episode in the preceding week. Response rates were calculated. Children were followed for a total of 4839 person-weeks. SMS replies were received for 4201 weeks. Thus, the rate of follow-up was 86.8%. Median responses rates were 94.2% (IQR: 86.1-100%). Weekly SMS is a feasible reporting tool for documenting bleeding episodes in children with haemophilia. It is associated with high response rates and minimal expense and intrusion. The use of SMS could be extended to encourage compliance to prophylactic treatment, particularly in adolescents with haemophilia.

Incidence and predictors of contracture after spinal cord injury--a prospective cohort study.

STUDY DESIGN: Prospective cohort study. OBJECTIVES: To determine incidence of contracture and develop prediction models to identify patients susceptible to contracture after spinal cord injury. SETTING: Two Sydney spinal cord injury units. METHODS: A total of 92 consecutive patients with acute spinal cord injury were assessed within 35 days of injury and 1 year later. Incidence of contracture at 1 year was measured in all major appendicular joints by categorizing range of motion on a 4-point scale (0-no contracture to 3-severe contracture), and in the wrist, elbow, hip and ankle by measuring range of motion at standardized torque. Multivariate models were developed to predict contracture at 1 year using age, neurological status, spasticity, pain and limb fracture recorded at the time of injury. RESULTS: At 1 year, 66% of participants developed at least one contracture (defined as ≥1 point deterioration on the 4-point scale). Incidence of contracture at each joint was: shoulder 43%, elbow and forearm 33%, wrist and hand 41%, hip 32%, knee 11% and ankle 40%. Incidence of contracture determined by standardized torque measures of range (defined as loss of ≥10 degrees) was: elbow 27%, wrist 26%, hip 23% and ankle 25%. Prediction models were statistically significant but lacked sufficient predictive accuracy to be clinically useful (R(2)≤31%). CONCLUSION: The incidence of contracture in major joints 1 year after spinal cord injury ranges from 11-43%. The ankle, wrist and shoulder are most commonly affected. It is difficult to accurately predict those susceptible to contracture soon after injury.

Measuring changes in muscle stiffness after eccentric exercise using elastography.

Muscle stiffness has been reported to increase following eccentric muscle exercise, but to date only indirect methods have been used to measure it. This study aimed to use Magnetic Resonance Elastography (MRE), a noninvasive imaging technique, to assess the time-course of passive elasticity changes in the medial gastrocnemius and soleus muscles before and after a bout of eccentric exercise. Shear storage modulus (G') and loss modulus (G'') measurements were made in eight healthy subjects for both muscles in vivo before, one hour after, 48 hours after and 1 week after eccentric exercise. The results show a 21% increase in medial gastrocnemius storage modulus following eccentric exercise with a peak occurring ~48 hours after exercise (before exercise 1.15 ± 0.23 kPa, 48 hours after 1.38 ± 0.27 kPa). No significant changes in soleus muscle storage modulus were measured for the exercise protocol used in this study, and no significant changes in loss modulus were observed. This study provides the first direct measurements in skeletal muscle before and after eccentric exercise damage and suggests that MRE can be used to detect the time course of changes to muscle properties.

Fitness and quality of life in children with haemophilia.

Prior to the introduction of prophylactic clotting factor, children with haemophilia were discouraged from physical activity due to the risk of bleeds. Reports of children with haemophilia having lower levels of fitness and strength than their healthy peers were therefore well accepted. This study aimed to establish whether these deficits continued, and specifically, whether Australian boys with haemophilia and von Willebrand disorder had lower strength and aerobic capacity than their peers, despite widespread use of prophylaxis. Forty-four boys aged 6.1-17.0 years (mean 10.9, SD 3.2) with haemophilia A and B and von Willebrand disorder participated in the study. Fitness, strength and body mass index (BMI) measures were compared with age- and gender-matched data from a representative cohort of school children. Quality of Life was measured using the Haemo-QoL to obtain baseline measures in an Australian population. There were no statistically significant or clinically important differences in aerobic fitness or BMI between the boys with haemophilia and controls in any age category. Boys with haemophilia in Years 4, 6 and 10 had greater strength than their peers. Australian boys with bleeding disorders do not have impaired aerobic capacity or strength compared with their peers. Quality of life in Australian boys with haemophilia is comparable to their European counterparts.

Changes in recruitment of transversus abdominis correlate with disability in people with chronic low back pain.

OBJECTIVES: Although motor control exercises have been shown to be effective in the management of low back pain (LBP) the mechanism of action is unclear. The current study investigated the relationship between the ability to recruit transversus abdominis and clinical outcomes of participants in a clinical trial. METHODS: Ultrasonography was used to assess the ability to recruit transversus abdominis in a nested design: a sample of 34 participants with chronic LBP was recruited from participants in a randomised controlled trial comparing the efficacy of motor control exercise, general exercise and spinal manipulative therapy. Perceived recovery, function, disability and pain were also assessed. RESULTS: Participants with chronic LBP receiving motor control exercise had a greater improvement in recruitment of transversus abdominis (7.8%) than participants receiving general exercise (4.9% reduction) or spinal manipulative therapy (3.7% reduction). The effect of motor control exercise on pain reduction was greater in participants who had a poor ability to recruit transversus abdominis at baseline. There was a significant, moderate correlation between improved recruitment of transversus abdominis and a reduction in disability (r = -0.35; 95% CI 0.02 to 0.62). CONCLUSION: These data provide some support for the hypothesised mechanism of action of motor control exercise and suggest that the treatment may be more effective in those with a poor ability to recruit transversus abdominis.

Passive mechanical properties of gastrocnemius in people with multiple sclerosis.

BACKGROUND: There is evidence to suggest that contractile properties of muscles in people with multiple sclerosis change as a consequence of demyelination in central nervous system. However, passive properties of muscles in people with multiple sclerosis have not been previously investigated. The purpose of this study was to characterise passive mechanical properties of gastrocnemius in people with multiple sclerosis and to compare these properties with those of gastrocnemius in neurologically normal people. METHODS: Ten people with multiple sclerosis having signs and symptoms of weakness in the legs (Disease step 1-3) and 10 age- and sex-matched healthy people participated in the study. Ultrasound images of muscle fascicles of medial gastrocnemius as well as passive ankle torque and ankle angle data were obtained simultaneously as the ankle was rotated through its full range with the knee in a range of positions. Analysis of ultrasound images and passive ankle torque-angle relations allowed us to derive the slack lengths and maximal strains of whole muscle-tendon units, muscle fascicles and tendons. Paired-samples t-tests were used to compare these variables in the two groups. RESULT: There was no difference between subjects with multiple sclerosis and healthy controls in the mean slack lengths and mean maximal strains of the whole muscle-tendon units or of their fascicles or tendons. INTERPRETATIONS: These data suggests that typically, in people with multiple sclerosis who have impaired lower limbs but are still ambulatory, the passive mechanical properties of the gastrocnemius muscles are normal.

Analgesic effects of treatments for non-specific low back pain: a meta-analysis of placebo-controlled randomized trials.

OBJECTIVE: Estimates of treatment effects reported in placebo-controlled randomized trials are less subject to bias than those estimates provided by other study designs. The objective of this meta-analysis was to estimate the analgesic effects of treatments for non-specific low back pain reported in placebo-controlled randomized trials. METHODS: Medline, Embase, Cinahl, PsychInfo and Cochrane Central Register of Controlled Trials databases were searched for eligible trials from earliest records to November 2006. Continuous pain outcomes were converted to a common 0-100 scale and pooled using a random effects model. RESULTS: A total of 76 trials reporting on 34 treatments were included. Fifty percent of the investigated treatments had statistically significant effects, but for most the effects were small or moderate: 47% had point estimates of effects of <10 points on the 100-point scale, 38% had point estimates from 10 to 20 points and 15% had point estimates of >20 points. Treatments reported to have large effects (>20 points) had been investigated only in a single trial. CONCLUSIONS: This meta-analysis revealed that the analgesic effects of many treatments for non-specific low back pain are small and that they do not differ in populations with acute or chronic symptoms.

Effects of 6 months of regular passive movements on ankle joint mobility in people with spinal cord injury: a randomized controlled trial.

STUDY DESIGN: Assessor-blinded within-subject randomized controlled trial. OBJECTIVE: To determine the effects of 6 months of regular passive movements on ankle joint mobility in people with spinal cord injury. SETTING: Community, Australia. METHODS: A total of 20 people with tetraplegia living in the community had one ankle randomized to a control group and the other to an experimental group. Carers administered passive movements to participants' experimental ankles for 10 min, 10 times a week for 6 months. The control ankles were left untreated. The primary outcome was passive ankle dorsiflexion range of motion. RESULTS: Adherence was high (mean adherence rate of 96%). Ankle dorsiflexion range of motion decreased by a mean (s.d.) of 2 degrees (4) in control ankles and increased by 2 degrees (4) in experimental ankles. The mean (95% confidence interval, CI) effect on ankle dorsiflexion range of motion was 4 degrees (95% CI, 2-6 degrees ). CONCLUSION: Regular passive movements have small effects on ankle joint mobility. It is unclear if these effects are clinically worthwhile.