Extremity Musculoskeletal Injury Research Articles

Musculoskeletal extremity injuries in a cohort of schoolchildren aged 6–12: A 2.5‐year prospective study

The objectives of this prospective school cohort study were to describe the epidemiology of diagnosed musculoskeletal extremity injuries and to estimate the injury incidence rates in relation to different settings, different body regions and injury types. In all, 1259 schoolchildren, aged 6-12, were surveyed weekly during 2.5 years using a new method of automated mobile phone text messaging asking questions on the presence of any musculoskeletal problems. All injuries were clinically diagnosed. Physical activity was measured from text messaging and accelerometers. A total number of 1229 injuries were diagnosed; 180 injuries in the upper extremity and 1049 in the lower extremity, with an overall rate of 1.59 injuries per 1000 physical activity units [95% confidence interval (CI) 1.50-1.68]. Upper extremities accounted for a rate of 0.23 (95% CI 0.20-0.27) and lower extremities accounted for 1.36 (95% CI 1.27-1.44). This study has added a wide overall perspective to the area concerning incidence and incidence rates of musculoskeletal extremity injuries in schoolchildren aged 6-12 years, including severe and less severe, traumatic, and overuse injuries. The understanding of injury epidemiology in children is fundamental to the acknowledgement and insurance of the appropriate prevention and treatment.

Seasonal variation in musculoskeletal extremity injuries in school children aged 6–12 followed prospectively over 2.5 years: a cohort study

ObjectivesThe type and level of physical activity in children vary over seasons and might thus influence the injury patterns. However, very little information is available on the distribution of injuries...

Weak Grip Strength Does not Predict Upper Extremity Musculoskeletal Symptoms or Injuries Among New Workers

Grip strength is often tested during post-offer pre-placement screening for workers in hand-intensive jobs. The purpose of this study was to evaluate the association between grip strength and upper extremity symptoms, work disability, and upper extremity musculoskeletal disorders (UE MSDs) in a group of workers newly employed in both high and low hand intensive work. 1,107 recently-hired workers completed physical examinations including grip strength measurements. Repeated surveys obtained over 3 years described the presence of upper extremity symptoms, report of physician-diagnosed musculoskeletal disorders (MSDs), and job titles. Baseline measured grip values were used in analytic models as continuous and categorized values to predict upper extremity symptoms, work disability, or UE MSD diagnosis. Twenty-six percent of males and 20 % of females had low baseline hand strength compared to normative data. Multivariate logistic regression analyses showed no consistent associations between grip strength and three health outcomes (UE symptoms, work disability, and MSDs) in this young cohort (mean age 30 years). Past MSD and work type were significant predictors of these outcomes. Physical hand strength testing was not useful for identifying workers at risk for developing UE MSDs, and may be an inappropriate measure for post-offer job screens.

Linear Modeling of Human Hand-Arm Dynamics Relevant to Right-Angle Torque Tool Interaction

A new protocol was evaluated for identification of stiffness, mass, and damping parameters employing a linear model for human hand-arm dynamics relevant to right-angle torque tool use. Powered torque tools are widely used to tighten fasteners in manufacturing industries. While these tools increase accuracy and efficiency of tightening processes, operators are repetitively exposed to impulsive forces, posing risk of upper extremity musculoskeletal injury. A novel testing apparatus was developed that closely mimics biomechanical exposure in torque tool operation. Forty experienced torque tool operators were tested with the apparatus to determine model parameters and validate the protocol for physical capacity assessment. A second-order hand-arm model with parameters extracted in the time domain met model accuracy criterion of 5% for time-to-peak displacement error in 93% of trials (vs. 75% for frequency domain). Average time-to-peak handle displacement and relative peak handle force errors were 0.69 ms and 0.21%, respectively. Model parameters were significantly affected by gender and working posture. Protocol and numerical calculation procedures provide an alternative method for assessing mechanical parameters relevant to right-angle torque tool use. The protocol more closely resembles tool use, and calculation procedures demonstrate better performance of parameter extraction using time domain system identification methods versus frequency domain. Potential future applications include parameter identification for in situ torque tool operation and equipment development for human hand-arm dynamics simulation under impulsive forces that could be used for assessing torque tools based on factors relevant to operator health (handle dynamics and hand-arm reaction force).

The Addition of Body Amor Diminishes Dynamic Postural Stability in Military Soldiers

Poor postural stability has been identified as a risk factor for lower extremity musculoskeletal injury. The additional weight of body armor carried by Soldiers alters static postural stability and may predispose Soldiers to lower extremity musculoskeletal injuries. However, static postural stability tasks poorly replicate the dynamic military environment, which places considerable stress on the postural control system during tactical training and combat. Therefore, the purpose of this study was to examine the effects of body armor on dynamic postural stability during single-leg jump landings. Thirty-six 101st Airborne Division (Air Assault) Soldiers performed single-leg jump landings in the anterior direction with and without wearing body armor. The dynamic postural stability index and the individual stability indices (medial-lateral stability index, anterior-posterior stability index, and vertical stability index) were calculated for each condition. Paired sample t-tests were performed to determine differences between conditions. Significant differences existed for the medial-lateral stability index, anterior-posterior stability index, vertical stability index, and dynamic postural stability index (p < 0.05). The addition of body armor resulted in diminished dynamic postural stability, which may result in increased lower extremity injuries. Training programs should address the altered dynamic postural stability while wearing body armor in attempts to promote adaptations that will result in safer performance during dynamic tasks.

Healthcare delivery aboard US Navy hospital ships following earthquake disasters: Implications for future disaster relief missions

Since 2004, the US Navy has provided ship-borne medical assistance during three earthquake disasters. Because Navy ship deployment for disaster relief (DR) is a recent development, formal guidelines for equipping and staffing medical operations do not yet exist. The goal of this study was to inform operational planning and resource allocation for future earthquake DR missions by 1) reporting the type and volume of patient presentations, medical staff, and surgical services and 2) providing a comparative analysis of the current medical and surgical capabilities of a hospital ship and a casualty receiving and treatment ship (CRTS). The following three earthquake DR operations were reviewed retrospectively: 1) USNS Mercy to Indonesia in 2004, 2) USNS Mercy to Indonesia in 2005, and 3) USNS Comfort/USS Bataan to Haiti in 2010. (The USS Bataan was a CRTS.) Mission records and surgical logs were analyzed. Descriptive and statistical analysis was performed. Comparative analysis of hospital ship and CRTS platforms was made based on firsthand observations. For the three missions, 986 patient encounters were documented. Of 1,204 diagnoses, 80 percent were disaster-related injuries, more than half of which were extremity trauma. Aboard hospital ships, healthcare staff provided advanced (Echelon III) care for disaster-related injuries and various nondisaster-related conditions. Aboard the CRTS, staff provided basic (Echelon II) care for disaster-related injuries. Our data indicate that musculoskeletal extremity injuries in sex- and age-diverse populations comprised the majority of clinical diagnoses. Current capabilities and surgical staffing of hospital ships and CRTS platforms influenced their respective DR operations, including the volume and types of surgical care delivered.

Associations between childhood obesity and upper and lower extremity injuries

ObjectivesTo estimate the overall and age-specific associations between obesity and extremity musculoskeletal injuries and pain in children.MethodsThis cross-sectional study used information from electronic medical records of 913 178 patients aged...

CSM 2012 Orthopaedic Section Platform Presentations (Abstracts OPL1–OPL64)

CSM 2012 Orthopaedic Section Platform Presentations (Abstracts OPL1–OPL64)

The impact of an increase in work rate on task demands for a simulated industrial hand tool assembly task

Global competition in the manufacturing sector has created an environment for continuous improvement resulting in methods to increase capacity while lowering cost. Speed Fastening (SF) is one manufacturing assembly method currently being modified to improve its production capacity. This semi-automated riveting process is limited by a lack of continuous feed of fasteners supplied to the tool. One path to productivity improvement that has been identified for improving productivity in SF is the development of a continuous feed tool, which would eliminate non-value added time currently scheduled for reloading. In preparation for the design of a new tool, a proactive investigation was conducted to characterize the influence of work rate (i.e. frequency of fastener insertion) on task demands (e.g. muscular effort, posture, etc.) for manual SF work. Twelve healthy female subjects participated in simulated SF work over four test sessions. The first test session was used to familiarize subjects with the task, as well as the data collection protocol. Subsequent test days were block randomized to one of three work rates (7, 14 and 21 fasteners per minute) with subjects required to complete 120 min of simulated SF work at waist and shoulder height. Overall, an increase in work rate imposed a significant increase ( p < 0.0001, 7 %MVIC) in the muscle activity recorded from the wrist extensors, despite the fact that no significant changes were observed in the 50th percentile upper extremity joint posture. As expected, the location of work (i.e. waist vs. shoulder height) imposed significant differences in muscle activity and joint posture. On average, participants assumed significantly greater magnitudes of wrist flexion ( p = 0.0025) and ulnar deviation ( p < 0.001) for shoulder height trials. Based on these findings it is expected that an increased work rate may expose SF operators to an elevated risk of MSI, particularly for work completed at shoulder height. Relevance to industry Repetitive work performed with a powered hand tool is considered a risk factor for the development upper extremity musculoskeletal injury. This investigation contributes to an improved understanding of the impact that an increased pace of work has on the physical demands of operators during a simulated industrial task.

Influence of Pain Associated with Musculoskeletal Disorders on Grip Force Timing

Study Design Retrospective repeated-measures design. Introduction Pain is a common symptom associated with musculoskeletal conditions. Purpose This study examined if pain resulting from a unilateral upper extremity musculoskeletal injury compromises the person's ability to rapidly initiate and release handgrip. Methods Delays in initiating and releasing a handgrip were determined for 28 individuals with “low pain” and 12 individuals with “high pain” in the injured upper extremity. All participants had no pain in the uninjured upper extremity. Results The high-pain group was 10% slower in initiating and releasing a grip than the low-pain group, in both injured and uninjured upper extremities, for both maximal and submaximal grips. In addition, delay in grip initiation was, on average, 8% longer for the injured than for the uninjured upper extremity. Conclusions Unilateral musculoskeletal pain appears to delay grip initiation and relaxation bilaterally, perhaps due to a centrally mediated mechanism. Level of Evidence n/a.

Are extremity musculoskeletal injuries in children related to obesity and social status? A prospective observational study in a district general hospital

Obesity is one of the several independent risk factors for the risk of fractures. Major epidemiological studies also suggested the social status of the patients to be a confounding factor. We aimed to look at the influence of obesity on fractures and to determine if the social status of the patients is a confounding factor. This is an observational study of 560 children with musculoskeletal injuries who presented over a period of 8months and the data were collected prospectively. Obesity status and social deprivation index were estimated. The prevalence of overweight and obese children was 29.9%. Twenty-four percent of the boys and 31% of the girls were obese (P=0.2). In the group of most deprived areas, the prevalence of obesity increased to 40% in those needing admission for intervention. Although there is a slight increase in obesity, there is no suggestion of increased rate of fractures in deprived areas. Upper limb injuries were more predominant, with distal radius fracture being the most common injury. Boys sustain fractures twice as often as girls. There is a tendency to increasing obesity with increasing age.

Landing Impact, Hip Kinematics, and Hip Strength Predict Dynamic Postural Stability in Army 101st Airborne

Postural instability contributes to unintentional lower extremity musculoskeletal injury. It is unclear if reported contributors to knee injury influence dynamic postural stability. PURPOSE: To determine if peak vertical ground reaction force (vGRF), sagittal and frontal plane knee and hip kinematics at initial contact, knee flexor/extensor strength, and hip abductor/adductor strength significantly predict dynamic postural stability index (DPSI). METHODS: Thirty nine male Army 101st Airborne (Air Assault) soldiers participated (26.3±5.6 yrs, 176.9±8.5 cm, 81.0±17.7 kg). Three dimensional kinematic and ground reaction forces (GRFs) were captured with a motion capture system interfaced with a force plate. Subjects performed a double-leg forward jump over a 12" hurdle with a single-leg landing on a force plate positioned at a distance of 40% subject height. Subjects landed on the dominant limb, stabilized as quickly as possible, and maintained single-leg balance with hands at the waist. DPSI was calculated using three dimensional GRFs from the first three seconds following initial contact. Isokinetic knee strength at 60o/sec and side-lying isometric hip strength at 10o hip abduction were tested using a multi-mode dynamometer. Strength and peak vGRF were normalized to % body weight. A stepwise multiple linear regression was performed to determine if the independent variables significantly predicted DPSI. The F probability for variable entry of.05, F probability for variable removal of.10, and alpha level of.05 for model significance was set a priori. RESULTS: Significant predictors in the linear regression model of DPSI include peak vGRF, hip abduction strength, and hip flexion/extension angle at initial contact (p <.001; R2 =.88; respective b=.0001, -.0013,.0018; constant=.0141). CONCLUSIONS: Dynamic postural stability for soldiers of the Army 101st Airborne (Air Assault) may be optimized by decreasing landing impact, increasing hip abduction strength, and increasing hip flexion at initial contact during landing tasks. Current injury prevention strategies targeting the significant knee injury contributors may concurrently benefit dynamic postural stability. Investigations are warranted to assess effects of training targeting the hip on dynamic postural stability.

Systematic Review of the Role of Occupational Health and Safety Interventions in the Prevention of Upper Extremity Musculoskeletal Symptoms, Signs, Disorders, Injuries, Claims and Lost Time

Little is known about the most effective occupational health and safety (OHS) interventions to reduce upper extremity musculoskeletal disorders (MSDs) and injuries. A systematic review used a best evidence synthesis approach to address the question: "do occupational health and safety interventions have an effect on upper extremity musculoskeletal symptoms, signs, disorders, injuries, claims and lost time?" The search identified 36 studies of sufficient methodological quality to be included in data extraction and evidence synthesis. Overall, a mixed level of evidence was found for OHS interventions. Levels of evidence for interventions associated with positive effects were: Moderate evidence for arm supports; and Limited evidence for ergonomics training plus workstation adjustments, new chair and rest breaks. Levels of evidence for interventions associated with "no effect" were: Strong evidence for workstation adjustment alone; Moderate evidence for biofeedback training and job stress management training; and Limited evidence for cognitive behavioral training. No interventions were associated with "negative effects". It is difficult to make strong evidenced-based recommendations about what practitioners should do to prevent or manage upper extremity MSDs. There is a paucity of high quality OHS interventions evaluating upper extremity MSDs and none focused on traumatic injury outcomes or workplace mandated pre-placement screening exams. We recommend that worksites not engage in OHS activities that include only workstation adjustments. However, when combined with ergonomics training, there is limited evidence that workstation adjustments are beneficial. A practice to consider is using arm supports to reduce upper extremity MSDs.

Frontal Plane Lower Extremity Biomechanics During Walking in Boys Who Are Overweight Versus Healthy Weight

To compare frontal plane lower extremity biomechanics during walking in adolescent boys who were overweight (OW) versus healthy weight (HW). Fourteen boys (7 considered HW, body mass index for age <85th percentile; age 10.8 +/- 0.7 years; 7 considered OW, body mass index for age >95th percentile; age 12.0 +/- 0.7 years) participated. Three-dimensional kinematic data were collected during walking at self-selected speeds. Group means were compared using Student's t tests (alpha = 0.05). Significant differences were found in timing of rearfoot motions and moments, amplitude of knee motion peaks, timing of knee moment peaks, and timing and amplitudes of peak hip motion and moments. Boys who were OW collapsed into hip adduction and knee valgus during stance and attempted to compensate with rearfoot inversion. Observed differences in frontal plane kinematics during walking suggest that boys who are OW have increased risk of lower extremity musculoskeletal injuries and dysfunction.

A Physiological and Psychological Basis for Anti-Pronation Taping from a Critical Review of the Literature

Anti-pronation taping is a treatment technique commonly used by clinicians in the management of lower extremity musculoskeletal pain and injury. The clinical efficacy of anti-pronation tape is described anecdotally and has some support through clinical trials for some foot conditions. However, the mechanism(s) underlying its clinical efficacy is unknown, but are broadly categorized under mechanical, neurophysiological and psychological hypotheses. This article explores these hypotheses and contributes to the understanding of the technique.A computer database search was conducted to identify relevant experimental studies using an a priori defined search strategy. Data were extracted from reviewed articles and wherever possible mean differences between baseline and taped condition and the 95% confidence interval, as well as percentage change scores and effect size statistics were calculated. Articles were organized pertaining to the hypothetical mechanism investigated and presented accordingly into biomechanical, neurophysiological or psychological paradigms.Overall, the research to date has focused predominantly on the mechanical paradigm with far fewer papers being found for the neurophysiological and psychological paradigms. The literature provides evidence that anti-pronation tape has a biomechanical effect, which has been demonstrated by increases in navicular height and medial longitudinal arch height, reductions in tibial internal rotation and calcaneal eversion and alteration of plantar pressure patterns, under both static (i.e. standing) and dynamic (i.e. walking, jogging, running) conditions. The reduction in pronation was dependent on the surrogate measure of pronation used, but generally ranged from as little as 5% increase in longitudinal arch height during jogging to as much as a 33% change in calcaneal eversion during walking. Preliminary evidence from few studies suggests that anti-pronation tape has a neurophysiological effect as it has been shown to reduce the activity of several muscles of the leg during dynamic tasks such as walking, hopping, cutting, back pedalling and drop jumps. Data were difficult to extract from these papers, but it would appear from a small study that the reduction is in the order of about 45% for tibialis posterior. To date, there has been limited investigation of the psychological effects of anti-pronation tape. A main issue, as with most placebo or sham interventions for physical therapy research, is that of an appropriate comparator in this regard. Consequently, these effects are currently not well understood. This article reports of evidence in support of anti-pronation tape exerting a biomechanical effect. As its name suggests, it does reduce pronation. There is emerging evidence of a neurophysiological effect, which is generally one of reduction in muscle activity, but caution is urged in over-interpreting a few studies on small sample sizes. Further research is required in this paradigm before sports medicine practitioners can utilize these findings in day-to-day clinical practice. Due to insufficient evidence, this article was unable to draw any conclusions as to the psychological effects of the tape, but the article does prompt the need for further exploration into the possible role of placebo in the clinical effects of anti-pronation taping.

Comparison of ergonomic risk assessments in a repetitive high-risk sawmill occupation: Saw-filer

Aims The aims of this study are to: (1) compare the results of 5 ergonomic risk assessment methods calculated with quantified physical exposure information, (2) examine the effect of multiple definitions of the posture and exertion variable on the risk assessment methods, (3) describe the variability in risk assessment scores between workers, (4) examine the ability of risk assessment component scores to differentiate between facilities with significantly different levels of exposure, and (5) examine the association between risk output and recorded incidence rates. Scope Quantified physical exposure information collected from 15 saw-filers in four sawmill facilities was used to calculate the RULA, REBA, ACGIH TLV, Strain Index and OCRA procedures based on multiple posture and exertion variable definitions. Results Recorded incidence of upper extremity musculoskeletal injury in the saw-filer position ranged from 0.12 to 0.86 per person year worked. All risk assessment methodologies examined (with the exception of the ACGIH TLV calculated with %MVC) agreed a level of risk was associated with performance of the saw-filer job. Posture and exertion variable definition was observed to have a significant effect on the component scores and/or risk output of all methods assessed. Meaningful variability in risk assessment scores was observed between workers. Components of all assessments, with the exception of the ACGIH TLV, differentiated between facilities assessed. Average risk index scores of the SI and OCRA procedures were observed to increase as recorded incidence of injury increased; however statistical significance was not demonstrated. Conclusions Suggestive evidence exists that the components of the strain index and OCRA methods measuring posture and frequency were sensitive to actual differences between facilities and that the combined role of physical exposures in precipitation of musculoskeletal injury was accounted for. Posture and exertion variable definitions were observed to significantly affect the component scores and/or risk output of all methods. Relevance to industry An understanding of inter subject variability, the effect of variable definition selected, and the sensitivity of risk output to incidence of injury are necessary to correctly apply ergonomic risk assessments in industrial prevention efforts.

Prevalence of upper extremity musculoskeletal injuries among recreational badminton players

Prevalence of upper extremity musculoskeletal injuries among recreational badminton players

Bmi Versus Exercise Impacts Injuries/illnesses Rates In Obese And Overweight Individuals

PURPOSE: To examine overweight and obese participants in a weight loss or weight gain prevention program to determine the type of injuries observed, and predictors of physical activity injuries. METHODS: 489 sedentary participants (BMI> 25 kg/m2) were randomized into either a control group or 1 of 5 behavioral weight loss programs that emphasized both a dietary and exercise component. Three programs restricted calories to 1200–1500/day and exercise progressed to 200 min/wk, and 2 programs had no dietary intake allowances but encouraged healthy eating with exercise progressing to 150 or 300 min/wk. Walking was prescribed as the primary mode of exercise. During the 18 month intervention, participants reported at 6 month intervals any injury or illness that affected their ability to exercise. Three separate survival models were built; all injuries, upper body musculoskeletal injuries, and lower body musculoskeletal injuries. RESULTS: 43% reported at least 1 injury/illness that affected their ability to exercise. The most common self-reported injuries or illnesses that affected the participant's ability to exercise were lower body musculoskeletal (∼20%), cold/flu/respiratory infections (∼17%) and upper body musculoskeletal injuries (∼12%). Approximately 33% of the lower body musculoskeletal injuries were attributed to knee injuries. Other common lower extremity musculoskeletal injuries included sprains (14%), tendonitis (12%), hip injuries (8%), general muscular injury (8%), spur (8%) and plantar fascitis (5%). Exercise was the sole contributor for 3% of the injuries, with 57% of the injuries not caused by exercise. 57% of the injuries or illnesses affected exercise participation for one week or less, with less than 10% affecting exercise participation for 3 months or longer. Injury rates between the various treatment groups did not differ from the control group. A higher BMI resulted in earlier reporting of an injury or illness. CONCLUSION: Injury rates for obese and overweight participants that initiated an exercise program were comparable to a sedentary control group. These data suggest that BMI contributes to the onset of injuries and illness. However, the prevalence of injuries is low with most only affecting exercise participation for 1 week or less.

Assessment of physical demands and comparison of multiple exposure definitions in a repetitive sawmill job: board edger operator

The primary objectives of the study were to 1) describe the physical exposures in a sawmill job with a high incidence of upper extremity musculoskeletal injuries in terms of multiple measures of posture, exertion and frequency (with varying definitions) and 2) to examine the comparability of those definitions. Surface electromyography and electrogoniometry were used to quantify the muscle demands and joint motions. Fourteen board edger operators from two sawmill facilities participated. All exposure assessments, with the exception of surface EMG measurements, were performed on the production lines. EMG measurements were performed within the facility in a location removed from the production line. The measurements showed that, on average, ranges of motions of 59, 102 and 84 degrees respectively in the planes of wrist radial/ulnar deviation, flexion/extension and pronation/supination were required to perform the job. Significant differences (p < .001) were observed between ranges of motion defined by peak postures and those due to peak postures required to perform the primary task only. Performance of the primary task required an average of 32% of maximum voluntary contraction from the forearm muscles assessed. Repetitions per day ranged, on average, from 2,015 to 9,365. Incidence of reported upper extremity musculoskeletal injuries in the two facilities assessed was found to be higher with the greater total exposure. However, examination of the trend with a standardized measure of injury incidence was not possible.

Modulation of soleus H-reflex by presynaptic spinal mechanisms during varying surface and ankle brace conditions

Aims Reflex excitability is modulated in part by presynaptic spinal mechanisms. Presynaptic inhibition may prevent an over-response of the motoneuron pool to afferent information. A paired-reflex depression (PRD) conditioning protocol can be used to monitor reflex plasticity. Manipulation of stance, surface, and external bracing are common methods of rehabilitating and treating lower extremity musculoskeletal injuries. The intent of this study was to evaluate changes in PRD of the soleus H-reflex during single-leg stance under varying stability conditions. Methods Seven trials were completed for each condition in ten healthy volunteers (age = 23 ± 1.8 yr, weight 65.0 ± 11.3 kg, height = 168.7 ± 28.0 cm). The conditioning stimuli were composed of soleus H-reflex pairs evoked 80 ms apart at an equal intensity. The mean percent decrease of the second H-reflex relative to the first represented PRD. Results A 2×2 repeated measures ANOVA ( P < 0.05) was used to evaluate influence of surface (foam, no foam) and support (semi-rigid ankle brace, no ankle brace) on PRD. Main effects testing revealed a significantly greater soleus PRD ( P = .034) for the foam surface (62.5%) compared the flat surface (57.5%). Ankle brace application did not influence soleus PRD ( P = 0.63). Conclusion The increase in soleus PRD during the foam condition suggests depression of the motoneuron pool. This may lessen postural over-corrections while maintaining upright stance during less stable conditions. No change in PRD during the ankle brace condition suggests that mechanical reinforcement provided an increase in ankle stability, decreasing the demand on the motoneuron pool.