Epigenetic differences in stress response gene FKBP5 among children with abusive vs accidental injuries.

BACKGROUND: Survivors of child abuse experience high rates of adverse physical and mental health outcomes. Epigenetic alterations in the stress response system, the FKBP5 gene specifically, have been implicated as one mechanism that may link abuse to lifelong health issues. Prior studies primarily included older individuals with a remote history of maltreatment; our objective was to test for differential methylation of FKBP5 in children with abusive vs accidental injuries at the time of diagnosis. METHODS: We conducted a cross-sectional pilot study of acutely injured children <4 years old at two children's hospitals (n = 82). Research personnel collected injury histories, buccal swabs (n = 65), and blood samples (n = 25) to measure DNA methylation. An expert panel classified the injuries as abusive, accidental, or indeterminate. RESULTS: Children with abusive as compared to accidental injuries had lower methylation of the FKBP5 promoter in buccal and blood cells, even after controlling for injury severity, socioeconomic status, and psychosocial risk factors. CONCLUSION: These findings suggest that epigenetic variation in FKBP5 may occur at the earliest indication of abuse and may be associated with delayed resolution of the HPA axis stress response. Additional testing for epigenetic differences in larger sample sizes is needed to further verify these findings. IMPACT: Children (<4 years old) with abusive compared to accidental injuries showed lower methylation of the FKBP5 promoter in buccal and blood cells at the time of initial diagnosis even after controlling for injury severity, socioeconomic status, and psychosocial risk factors. Early childhood physical abuse may impact the epigenetic regulation of the stress response system, including demethylation within promoters and enhancers of the FKBP5 gene, even at the earliest indication of abuse. The findings are important because unmitigated stress is associated with adverse health outcomes throughout the life-course.

Femur morphology in healthy infants and young children.

The objective of this study was to characterize femur morphology in healthy infants and young children. Anterior-posterior (AP) radiographs of the femur from children age 0-3 years with no history of bone disease were obtained from two children's hospitals and one medical examiner's office. Femur morphological measures (bone length, minimum diaphysis diameter, growth plate width, and femur radius of curvature) and sectional structural measures were determined. Measures were described and compared based on subject age and mass. Relationships between measures and age and mass were evaluated. The 169 AP femur radiographs were obtained from 99 children (59.6% males, median age = 12.0 months, IQR = 0-27.5 months, median body weight = 10.0 kg, IQR = 4.4-15.6 kg). Femur length (rs  = 0.97, p < 0.001; rs  = 0.89, p < 0.001), trochanter width (rs  = 0.86, p < 0.001; rs  = 0.85, p < 0.001), minimum diaphysis diameter (rs  = 0.91, p < 0.001; rs  = 0.87, p < 0.001), and growth plate width (rs  = 0.91, p < 0.001; rs  = 0.84, p < 0.001) increased with age and weight, respectively. Cross-sectional area (rs  = 0.87; rs  = 0.86; p < 0.01), polar moment of inertia (rs  = 0.91; rs  = 0.87; p < 0.001), moment of inertia (rs  = 0.91; rs  = 0.87; p < 0.001), polar modulus (rs  = 0.91; rs  = 0.87; p < 0.001) and medullary canal diameter (rs  = 0.83, p < 0.001; rs  = 0.73, p < 0.001) at the minimum diaphysis also increased with age and weight, respectively. Changes during rapid bone growth are important to understanding fracture risk in infants and young children as they transition to independent walking. Femur length, trochanter width, minimum diaphysis diameter and growth plate width increased with age and weight. Structural properties associated with fracture resistance also increased with age and weight.

Retraction Note to: Radiographic characteristics that delineate abusive from accidental skull fractures, including the significance of fracture extension to sutures.

The authors have retracted the abstract #029 "Radiographic characteristics that delineate abusive from accidental skull fractures, including the significance of fracture extension to sutures".

Characteristics of rib fractures in young abused children.

BACKGROUND: The presumed mechanism of rib fractures in abuse is violent grasping of the torso causing anterior-posterior chest compression. We hypothesized an asymmetrical distribution of rib fractures in abused infants given the greater incidence of right-hand dominance within the general population. OBJECTIVE: The objective of this study was to characterize rib fractures in abused children, particularly sidedness; additionally, we evaluated the sidedness of other abusive skeletal fractures. MATERIALS AND METHODS: We reviewed medical records from abused children (0-18 months old) with rib fractures. We also retrospectively reviewed their radiographs to determine characteristics of rib fractures (number, side, rib region, level, acuity) and other skeletal fractures (number, side, location), as well as differences in the distribution of rib and other skeletal fractures. RESULTS: A total of 360 rib fractures were identified on 273 individual ribs involving 78 abused children. Sixty-three children (81%) had multiple rib fractures. There was a significantly greater number of left-side rib fractures (67%) than right-side fractures (P<0.001). Fractures were most often identified in the posterior and lateral regions and mid level of the ribcage (Ribs 5 through 8). Fifty-four percent of subjects had other skeletal fractures; these non-rib fractures were also predominantly on the left side (P=0.006). CONCLUSION: In our study of abused children, there was a higher incidence of rib fractures in the posterior, lateral and mid-level locations. Additionally, we found a predominance of left-side rib and other skeletal fractures. Further research is needed to understand whether factors such as perpetrator handedness are associated with these unequal distributions of fractures in abused children.

Classifying Injuries in Young Children as Abusive or Accidental: Reliability and Accuracy of an Expert Panel Approach.

OBJECTIVE: To assess interrater reliability and accuracy of an expert panel in classifying injuries of patients as abusive or accidental based on comprehensive case information. STUDY DESIGN: Data came from a prospective, observational, multicenter study investigating bruising characteristics of children younger than 4 years. We enrolled 2166 patients with broad ranges of illnesses and injuries presenting to one of 5 pediatric emergency departments in whom bruises were identified during examination. We collected comprehensive data regarding current and past injuries and illnesses, and provided deidentified, standardized case information to a 9-member multidisciplinary panel of experts with extensive experience in pediatric injury. Each panelist classified cases using a 5-level ordinal scale ranging from definite abuse to definite accident. Panelists also assessed whether report to child protective services (CPS) was warranted. We calculated reliability coefficients for likelihood of abuse and decision to report to CPS. RESULTS: The interrater reliability of the panelists was high. The Kendall coefficient (95% CI) for the likelihood of abuse was 0.89 (0.87, 0.91) and the kappa coefficient for the decision to report to CPS was 0.91 (0.87, 0.94). Reliability of pairs and subgroups of panelists were similarly high. A panel composite classification was nearly perfectly accurate in a subset of cases having definitive, corroborated injury status. CONCLUSIONS: A panel of experts with different backgrounds but common expertise in pediatric injury is a reliable and accurate criterion standard for classifying pediatric injuries as abusive or accidental in a sample of children presenting to a pediatric emergency department.

Canine cranial cruciate ligament deficient stifle biomechanics associated with extra-articular stabilization predicted using a computer model.

OBJECTIVE: To evaluate lateral fabellotibial suture (LFTS) and TightRope CCL (TR) extra-articular stabilization biomechanics in the cranial cruciate ligament (CrCL)-deficient canine stifle joint during the stance phase of gait. STUDY DESIGN: Computer simulations. ANIMALS: Healthy 33-kg Golden Retriever. METHODS: LFTS and TR were implemented in a previously developed 3-D quasi-static rigid body CrCL-deficient canine pelvic limb computer model simulating the stance phase of gait. Ligament loads, relative tibial translation, and relative tibial rotation were determined and compared across the CrCL-intact, CrCL-deficient, and extra-articular stabilized stifle joints. RESULTS: Compared to the CrCL-intact stifle, peak caudal cruciate and lateral collateral ligament (LCL) loads were increased in the LFTS-managed stifle, peak caudal cruciate and LCL loads were decreased in the TR-managed stifle, and peak medial collateral and patellar ligament (PL) loads were similar for both techniques. Compared to the CrCL-deficient stifle, peak caudal cruciate, lateral collateral, and medial collateral ligament loads decreased, and peak PL load was similar in the LFTS- and TR-managed stifle joints. Peak relative tibial translation decreased, and peak relative tibial rotation changed from internal rotation to external rotation in the LFTS- and TR-managed stifle joints compared to the CrCL-deficient stifle. CONCLUSION: Our computer model predicted controlled tibial translation, decreased cruciate and collateral ligament loads, and a change in femorotibial rotation from internal to external with LFTS and TR stifle management as compared to the CrCL-deficient stifle. This study demonstrates how computer modeling can be used to evaluate biomechanics of stifle stabilization surgical techniques.

Canine Stifle Biomechanics Associated With a Novel Extracapsular Articulating Implant Predicted Using a Computer Model.

OBJECTIVE: To evaluate the influence of the Simitri Stable in Stride™ extracapsular articulating implant (EAI) on canine stifle biomechanics in the cranial cruciate ligament (CrCL)-deficient stifle using a 3-dimensional (3D) quasi-static rigid body canine pelvic limb computer model simulating the stance phase of gait. STUDY DESIGN: Computer simulations. ANIMALS: Five-year-old neutered male golden retriever (33 kg). METHODS: The EAI was implemented in a previously developed 3D CrCL-deficient canine pelvic limb computer simulation model. Ligament loads, relative tibial translation, and relative tibial rotation were determined and compared to the CrCL-intact and CrCL-deficient stifle. RESULTS: The EAI significantly increased peak caudal cruciate and medial collateral ligament loads, significantly changed when peak lateral collateral ligament load occurred, and did not significantly affect peak patellar ligament load compared to the CrCL-intact stifle. Compared to the CrCL-deficient stifle, peak caudal cruciate, lateral collateral, and medial collateral ligament loads significantly decreased in the EAI-managed stifle. Despite decreased peak caudal cruciate ligament loading, the EAI-managed stifle generated local maxima that exceeded those of the CrCL-deficient stifle at various intervals of stance. Peak relative tibial translation and rotation significantly decreased in the EAI-managed stifle compared to the CrCL-deficient stifle. CONCLUSION: Model-predicted stifle biomechanics differed after EAI system application in the CrCL-deficient stifle, but were not restored to that of the CrCL-intact stifle.

Biomechanical investigation of the classic metaphyseal lesion using an immature porcine model.

OBJECTIVE: The classic metaphyseal lesion is highly associated with abuse in infants. Classic metaphyseal lesions, also referred to as corner or bucket-handle fractures, are fractures through the metaphyseal region of the long bones near the growth plate. Knowledge of the biomechanics and mechanisms necessary to produce a classic metaphyseal lesion may provide insight into the injury causation associated with this unique fracture type. Thus, the purpose of this study was to investigate loading conditions necessary to create a classic metaphyseal lesion using an immature porcine model. MATERIALS AND METHODS: Twenty-four pelvic limb specimens from 7-day-old and 3-day-old piglets were tested in lateral bending (varus and valgus) using an electromechanical testing machine. All specimens were loaded dynamically in four-point bending at a rate of 100 inches/min. Microcomputed tomography was performed on specimens before and after testing. Pre- and posttest CT images were compared to assess whether fracture had occurred. RESULTS: Fractures resembling classic metaphyseal lesions were identified in 12 of the 24 specimens. Microcomputed tomography images revealed trabecular disruptions visually similar to classic metaphyseal lesions in children. CONCLUSION: Metaphyseal fractures, consistent with clinical classic metaphyseal lesions, resulted from a single loading event delivering varus or valgus bending to the stifle (knee). A classic metaphyseal lesion is a unique type of fracture with specific morphologic characteristics. Therefore, we suggest using the term "classic metaphyseal fracture" in lieu of classic metaphyseal lesion to improve precision of terminology.

Ramp-related incidents involving wheeled mobility device users during transit bus boarding/alighting.

OBJECTIVES: To estimate the prevalence of wheeled mobility device (WhMD) ramp-related incidents while boarding/alighting a public transit bus and to determine whether the frequency of incidents is less when the ramp slope meets the proposed Americans with Disabilities Act (ADA) maximum allowable limit of ≤9.5°. DESIGN: Observational study. SETTING: Community public transportation. PARTICIPANTS: WhMD users (N=414) accessing a public transit bus equipped with an instrumented ramp. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Prevalence of boarding/alighting incidents involving WhMD users and associated ramp slopes; factors affecting incidents. RESULTS: A total of 4.6% (n=35) of WhMD users experienced an incident while boarding/alighting a transit bus. Significantly more incidents occurred during boarding (6.3%, n=26) than during alighting (2.2%, n=9) (P<.01), and when the ramp was deployed to street level (mean slope=11.4°) compared with sidewalk level (mean slope=4.2°) (P=.01). The odds ratio for experiencing an incident when the ramp slope exceeded the proposed ADA maximum allowable ramp slope was 5.4 (95% confidence interval, 2.4-12.2; P<.01). The odds ratio for assistance being rendered to board/alight when the ramp slope exceeded the proposed ADA maximum allowable ramp slope was 5.1 (95% confidence interval, 2.9-9.0; P<.01). CONCLUSIONS: The findings of this study support the proposed ADA maximum allowable ramp slope of 9.5°. Ramp slopes >9.5° and ramps deployed to street level are associated with a higher frequency of incidents and provision of assistance. Transit agencies should increase awareness among bus operators of the effect kneeling and deployment location (street/sidewalk) have on the ramp slope. In addition, ramp components and the built environment may contribute to incidents. When prescribing WhMDs, skills training must include ascending/descending ramps at slopes encountered during boarding/alighting to ensure safe and independent access to public transit buses.

Canine Stifle Biomechanics Associated With Tibial Tuberosity Advancement Predicted Using a Computer Model.

OBJECTIVE: To evaluate the effects of tibial tuberosity advancement (TTA) on canine biomechanics in the cranial cruciate ligament (CrCL)-deficient stifle using a 3-dimensional quasi-static rigid body pelvic limb computer model simulating the stance phase of gait. STUDY DESIGN: Computer simulations. ANIMALS: A 5-year-old neutered male Golden Retriever weighing 33 kg. METHODS: A TTA was implemented in a previously developed canine pelvic limb computer model using the tibial plateau slope and common tangent planning techniques. Ligament loads, relative tibial translation, and relative tibial rotation were determined and compared to CrCL-intact and CrCL-deficient stifles. RESULTS: The TTA significantly decreased peak caudal cruciate ligament load, significantly increased peak lateral collateral ligament load, and significantly changed peak medial collateral ligament load occurrence, while there was no significant difference in peak patellar ligament load compared to the CrCL-intact stifle. Compared to the CrCL-deficient stifle, peak caudal cruciate, lateral collateral and medial collateral ligament loads significantly decreased, while peak patellar ligament load was similar, peak relative tibial translation significantly decreased and peak relative tibial rotation was converted to external rotation in the TTA-treated stifle. Each TTA planning technique generated similar caudal cruciate, medial collateral, and patellar ligament loading as well as relative tibial translation, but lateral collateral ligament loading and occurrence of relative tibial rotation differed significantly across the techniques. CONCLUSIONS: Model-predicted stifle ligament loads improved following TTA compared to the CrCL-deficient stifle, but TTA did not restore CrCL-intact stifle biomechanics. The TTA effectively reduced tibial translation, but tibial rotation was not stabilized.

Health care utilization and barriers experienced by individuals with spinal cord injury.

OBJECTIVES: To identify from whom individuals with spinal cord injury (SCI) seek health care, the percentage who receive preventative care screenings, and the frequency and types of barriers they encounter when accessing primary and specialty care services; and to examine how sociodemographic factors affect access to care and receipt of preventative screenings. DESIGN: Cross-sectional, observational study using an Internet-based survey. SETTING: Internet based. PARTICIPANTS: Adults (N=108) with SCI who use a wheelchair as their primary means of mobility in the community. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Health care utilization during the past year, barriers encountered when accessing health care facilities, and receipt of routine care and preventative screenings. RESULTS: All but 1 participant had visited a primary care provider within the past 12 months, and 85% had had ≥ 1 visit to specialty care providers. Accessibility barriers were encountered during both primary care (91.1%) and specialty care (80.2%) visits; most barriers were clustered in the examination room. The most prevalent barriers were inaccessible examination tables (primary care=76.9%; specialty care=51.4%) and lack of transfer aids (primary care=69.4%; specialty care=60.8%). Most participants had not been weighed during their visit (89%) and had remained seated in their wheelchair during their examinations (85.2%). Over one third of individuals aged ≥ 50 years had not received a screening colonoscopy, 60% of women aged ≥ 50 years had not had a mammogram within the past year, 39.58% of women had not received a Papanicolaou smear within the previous 3 years, and only 45.37% of respondents had ever received bone density testing. CONCLUSIONS: Individuals with SCI face remediable obstacles to care and receive fewer preventative care screenings than their nondisabled counterparts. We recommend that clinics conduct Americans with Disabilities Act self-assessments, ensure that their clinical staff are properly trained in assisting individuals with mobility disabilities, and take a proactive approach in discussing preventative care screenings with their patients who have SCI.

Wheelchair securement and occupant restraint system (WTORS) practices in public transit buses.

The purpose of this study was to characterize wheelchair tiedown and occupant restraint system (WTORS) usage in public transit buses based on observations of wheelchair and scooter (wheeled mobility device: WhMD) passenger trips. A retrospective review of on-board video surveillance recordings of WhMD trips on fixed-route, large accessible transit vehicles (LATVs) was performed. Two hundred ninety-five video recordings were collected for review and analysis during the period June 2007-February 2009. Results showed that 73.6% of WhMDs were unsecured during transit. Complete use of all four tiedowns was observed more frequently for manual wheelchairs (14.9%) and power wheelchairs (5.5%), compared to scooters (0.0%), and this difference was significant (p=0.013). Nonuse or misuse (lap belt use only) of the occupant restraint system occurred during 47.5% of WhMD trips. The most frequently observed (52.5%) use of the lap belt consisted of bus operators routing the lap belt around the WhMD seatback in an attempt to secure the WhMD. These findings support the need for development and implementation of WTORS with improved usability and/or WTORS that can be operated independently by WhMD passengers and improved WTORS training for bus operators.

Wheeled mobility device transportation safety in fixed route and demand-responsive public transit vehicles within the United States.

An overview of the current status of wheelchair transportation safety in fixed route and demand-responsive, non-rail, public transportation vehicles within the US is presented. A description of each mode of transportation is provided, followed by a discussion of the primary issues affecting safety, accessibility, and usability. Technologies such as lifts, ramps, securement systems, and occupant restraint systems, along with regulations and voluntary industry standards have been implemented with the intent of improving safety and accessibility for individuals who travel while seated in their wheeled mobility device (e.g., wheelchair or scooter). However, across both fixed route and demand-responsive transit systems a myriad of factors such as nonuse and misuse of safety systems, oversized wheeled mobility devices, vehicle space constraints, and inadequate vehicle operator training may place wheeled mobility device (WhMD) users at risk of injury even under non-impact driving conditions. Since WhMD-related incidents also often occur during the boarding and alighting process, the frequency of these events, along with factors associated with these events are described for each transit mode. Recommendations for improving WhMD transportation are discussed given the current state of

RESNA's position on wheelchairs used as seats in motor vehicles.

This position paper is based on the premise that those who ride seated in wheelchairs are entitled to equivalent occupant safety when they are traveling in motor vehicles. The document summarizes research and best practice for safety and selection of crashworthy wheelchairs with the requisite features required by the WC19 safety standard when it is necessary for individuals to use a wheelchair as a seat in a motor vehicle. Recommendations are based on data from accident and injury databases, prior research and a synopsis of the design, testing, performance and labeling requirements of ANSI and ISO voluntary industry standards for wheelchair transportation safety. This paper is intended for an audience of consumers, rehabilitation and health care professionals, manufacturers of wheelchairs and wheelchair transportation equipment and those who make reimbursement and public policy decisions.

Head biomechanics of video recorded falls involving children in a childcare setting.

The objective of this study was to characterize head biomechanics of video-recorded falls involving young children in a licensed childcare setting. Children 12 to < 36 months of age were observed using video monitoring during daily activities in a childcare setting (in classrooms and outdoor playground) to capture fall events. Sensors (SIM G) incorporated into headbands worn by the children were used to obtain head accelerations and velocities during falls. The SIM G device was activated when linear acceleration was ≥ 12 g. 174 video-recorded falls activated the SIM G device; these falls involved 31 children (mean age = 21.6 months ± 5.6 SD). Fall heights ranged from 0.1 to 1.2 m. Across falls, max linear head acceleration was 50.2 g, max rotational head acceleration was 5388 rad/s2, max linear head velocity was 3.8 m/s and max rotational head velocity was 21.6 rad/s. Falls with head impact had significantly higher biomechanical measures. There was no correlation between head acceleration and fall height. No serious injuries resulted from falls-only 1 child had a minor injury. In conclusion, wearable sensors enabled characterization of head biomechanics during video-recorded falls involving young children in a childcare setting. Falls in this setting did not result in serious injury.

Investigation of femur fracture potential in common pediatric falls using finite element analysis.

A finite element (FE) model of an 11-month-old child's femur was developed to evaluate fracture risk in short-distance feet-first falls and bed falls. Pediatric material properties were applied to the FE model. Femur loading was derived from previously conducted fall experiments using a child surrogate where fall conditions (e.g., fall height, impact surface) were varied. Fracture thresholds based on principal stress and strain were used to examine potential for fracture. Peak stress/strain were significantly greater for feet-first falls from greater heights and onto harder impact surfaces. Feet-first falls exceeded some, but not all fracture thresholds. Bed falls did not exceed any fracture thresholds.

Validation of a Clinical Decision Rule to Predict Abuse in Young Children Based on Bruising Characteristics.

Importance: Bruising caused by physical abuse is the most common antecedent injury to be overlooked or misdiagnosed as nonabusive before an abuse-related fatality or near-fatality in a young child. Bruising occurs from both nonabuse and abuse, but differences identified by a clinical decision rule may allow improved and earlier recognition of the abused child. Objective: To refine and validate a previously derived bruising clinical decision rule (BCDR), the TEN-4 (bruising to torso, ear, or neck or any bruising on an infant <4.99 months of age), for identifying children at risk of having been physically abused. Design, Setting, and Participants: This prospective cross-sectional study was conducted from December 1, 2011, to March 31, 2016, at emergency departments of 5 urban children's hospitals. Children younger than 4 years with bruising were identified through deliberate examination. Statistical analysis was completed in June 2020. Exposures: Bruising characteristics in 34 discrete body regions, patterned bruising, cumulative bruise counts, and patient's age. The BCDR was refined and validated based on these variables using binary recursive partitioning analysis. Main Outcomes and Measures: Injury from abusive vs nonabusive trauma was determined by the consensus judgment of a multidisciplinary expert panel. Results: A total of 21 123 children were consecutively screened for bruising, and 2161 patients (mean [SD] age, 2.1 [1.1] years; 1296 [60%] male; 1785 [83%] White; 1484 [69%] non-Hispanic/Latino) were enrolled. The expert panel achieved consensus on 2123 patients (98%), classifying 410 (19%) as abuse and 1713 (79%) as nonabuse. A classification tree was fit to refine the rule and validated via bootstrap resampling. The resulting BCDR was 95.6% (95% CI, 93.0%-97.3%) sensitive and 87.1% (95% CI, 85.4%-88.6%) specific for distinguishing abuse from nonabusive trauma based on body region bruised (torso, ear, neck, frenulum, angle of jaw, cheeks [fleshy], eyelids, and subconjunctivae), bruising anywhere on an infant 4.99 months and younger, or patterned bruising (TEN-4-FACESp). Conclusions and Relevance: In this study, an affirmative finding for any of the 3 BCDR TEN-4-FACESp components in children younger than 4 years indicated a potential risk for abuse; these results warrant further evaluation. Clinical application of this tool has the potential to improve recognition of abuse in young children with bruising.

Ramps remain a barrier to safe wheelchair user transit bus ingress/egress.

Background: Wheelchair users (WCUs) often rely on ramps for access to transit buses. Previous studies indicate WCUs have difficulty using ramps for bus ingress/egress and many transportation-related incidents occur on ramps. However, experiences of WCU ramp usage during ingress/egress have not been fully described.Methods: Cross-sectional, internet-based survey of WCUs who ride transit buses was conducted. The participants were queried on frequency of bus usage, difficulty and incidents involving ramps, and factors contributing to difficulty and incidents. Wheelchair characteristics, primary condition, and whether participants received travel training were also captured. Chi-square was used to describe relationships between wheelchair type and frequency of difficulties and incidents, and odd ratios were used to determine likelihood of the incidents.Results: The majority (55.7%) of 384 participants reported using public transportation ≥ 1 per week. Seventy-eight percent of WCUs had ≥ 1 ramp incident over the past 3 years, with an increased likelihood of incidents occurring during ingress (OR = 1.53; CI 1.21-1.86). Of those who had an incident, 22% were injured or had damage to their wheelchair. Over 60% of those who had an incident identified steep ramp slope as being the contributing factor. Steep ramp slope, exterior ramp thresholds and wet surfaces were the most common contributing factors to difficulty using ramps.Conclusion: This is the first large-scale US study enabling WCUs to describe their experiences using transit bus ramps. Despite ADA guidelines, steep ramps remain the primary factor contributing to incidents and difficulty when using ramps to access transit buses.Implications for rehabilitationThe discrepancy between ADA maximum allowable ramp slopes for the built environment and transit buses may require an increased level of effort that is a barrier to transportation accessibility for some wheelchair users.Wheelchair users who access transit buses should be made aware of, and trained, to navigate ramp configurations found in the environment.We suggest rehabilitation therapists provide skills training specific to navigating transit bus ramp slopes that may be steeper and narrower than building ramps.

Long bone fracture characteristics in children with medical conditions linked to bone health.

BACKGROUND: Knowledge of fracture characteristics among children with medical conditions affecting bone could help to distinguish medical causes from child abuse. OBJECTIVE: Characterize long bone fracture morphology among children diagnosed with medical conditions linked to bone health. PARTICIPANTS AND SETTING: Patients <18 years at a single pediatric hospital diagnosed with a medical condition linked to bone health and ≥1 long bone fracture were studied. METHODS: This retrospective medical record review categorized underlying medical diagnoses as: metabolic bone disease, genetic disorder of connective tissue, neurologic disorder and other chronic disease. A pediatric radiologist reviewed plain films to determine fracture type and location. Descriptive statistics, as well as logistic regression were used to compare fracture types by clinical characteristics. RESULTS: Ninety-four patients were included and their diagnoses were genetic connective disorder (19; 20.2 %), metabolic bone disease (16; 17.0 %), neurologic disorder (27; 28.7 %), and other (32; 34.0 %). A total of 216 long bone fractures were sustained; 52.1 % of children had >1 long bone fracture. Of the 216 fractures, 55 (25.5 %) were in children < 1 year, 118 (54.6 %) were associated with known trauma, and 122 (56.5 %) were in non-ambulatory patients. Lower extremity fractures occurred with greatest frequency and most fractures occurred at the mid-diaphysis. Transverse was the most common fracture type in all diagnostic categories. Children with metabolic disorders had highest odds of transverse fracture (COR 3.55, CI 1.45-8.67; neurologic disorders as reference group). CONCLUSIONS: Diseases affecting bone health can influence fracture morphology. Transverse fractures were most common in bones impacted by disease.

Development of a Canine Rigid Body Musculoskeletal Computer Model to Evaluate Gait.

BACKGROUND: Kinematic and kinetic analysis have been used to gain an understanding of canine movement and joint loading during gait. By non-invasively predicting muscle activation patterns and forces during gait, musculoskeletal models can further our understanding of normal variability and muscle activation patterns and force profiles characteristic of gait. METHODS: Pelvic limb kinematics and kinetics were measured for a 2 year old healthy female Dachshund (5.4 kg) during gait using 3-D motion capture and force platforms. A computed tomography scan was conducted to acquire pelvis and pelvic limb morphology. Using the OpenSim modeling platform, a bilateral pelvic limb subject-specific rigid body musculoskeletal computer model was developed. This model predicted muscle activation patterns, muscle forces, and angular kinematics and joint moments during walking. RESULTS: Gait kinematics determined from motion capture matched those predicted by the model, verifying model accuracy. Primary muscles involved in generating joint moments during stance and swing were predicted by the model: at mid-stance the adductor magnus et brevis (peak activation 53.2%, peak force 64.7 N) extended the hip, and stifle flexor muscles (biceps femoris tibial and calcaneal portions) flexed the stifle. Countering vertical ground reaction forces, the iliopsoas (peak activation 37.9%, peak force 68.7 N) stabilized the hip in mid-stance, while the biceps femoris patellar portion stabilized the stifle in mid-stance and the plantar flexors (gastrocnemius and flexor digitorum muscles) stabilized the tarsal joint during early stance. Transitioning to swing, the iliopsoas, rectus femoris and tensor fascia lata flexed the hip, while in late swing the adductor magnus et brevis impeded further flexion as biceps femoris tibial and calcaneal portions stabilized the stifle for ground contact. CONCLUSION: The musculoskeletal computer model accurately replicated experimental canine angular kinematics associated with gait and was used to predict muscle activation patterns and forces. Thus, musculoskeletal modeling allows for quantification of measures such as muscle forces that are difficult or impossible to measure in vivo.