Potential Injury Mechanisms Research Articles

Determining the optimum number of cycles for calculating joint coordination and its variability during running at different speeds: A timeseries analysis

Understanding the intricacies of human movement coordination and variability during running is crucial to unraveling the dynamics of locomotion, identifying potential injury mechanisms and understanding skill development. Identification of minimum number of cycles for calculation of reliable coordination and its variability could help with better test organization and efficient assessment time. By adopting a cross-sectional study design, this study investigated the minimum required cycles for calculating hip-knee, hip-ankle and knee-ankle coordination and their variability using a continuous relative phase (CRP) method. Twenty-nine healthy adults ran on a treadmill at speeds of 9, 12.5, and 16 km.h−1 while 3D kinematic data of their lower limbs were recorded using 6 optoelectronic cameras. Using Intraclass Correlation Coefficient (ICC) analysis, reliability between CRP and its variability (CRPv) in different gait cycles (3, 5, 10, 20, 30) was assessed for each speed. A minimum of 10 cycles was required for CRP calculation across all speeds, whereas CRPv necessitated a minimum of 30 cycles for moderate to good reliability. While increasing the number of cycles improved ICC values for inter-joint CRP, the same trend was not consistently observed for CRPv, emphasizing the importance of separately assessing CRP and its variability metrics.

Construction and validation of a rat model of acute necrotizing pancreatitis-associated intestinal injury.

Acute pancreatitis (AP) is an acute inflammatory reaction of the pancreatic tissue, which involves auto-digestion, edema, hemorrhage, and necrosis. AP can be categorized into mild, moderately severe, and severe AP, with severe pancreatitis also referred to as acute necrotizing pancreatitis (ANP). ANP is characterized by the accumulation of necrotic material in the peritoneal cavity. This can result in intestinal injury. However, the mechanism of ANP-associated intestinal injury remains unclear. We established an ANP-associated intestinal injury rat model (ANP-IR model) by injecting pancreatitis-associated ascites fluid (PAAF) and necrotic pancreatic tissue at various proportions into the triangular area formed by the left renal artery and ureter. The feasibility of the ANP-IR model was verified by comparing the similar changes in indicators of intestinal inflammation and barrier function between the two rat models. In addition, we detected changes in apoptosis levels and YAP protein expression in the ileal tissues of rats in each group and validated them in vitro in rat epithelial crypt cells (IEC-6) to further explore the potential injury mechanisms of ANP-associated intestinal injury. We also collected clinical data from patients with ANP to validate the effects of PAAF and pancreatic necrosis on intestinal injury. Our findings offer a theoretical basis for restricting the buildup of peritoneal necrosis in individuals with ANP, thus promoting the restoration of intestinal function and enhancing treatment efficacy. The use of the ANP-IR model in further studies can help us better understand the mechanism and treatment of ANP-associated intestinal injury.NEW & NOTEWORTHY We constructed a rat model of acute necrotizing pancreatitis-associated intestinal injury and verified its feasibility. In addition, we identified the mechanism by which necrotic pancreatic tissue and pancreatitis-associated ascites fluid (PAAF) cause intestinal injury through the HIPPO signaling pathway.

Numerical analysis of injuries of e-scooter riders in frontal impacts against SUVs

The rising popularity of e-scooters in urban areas highlights the importance of understanding potential collision dynamics and consequences to enhance rider safety, especially since 80% of fatalities for these vulnerable road users result from incidents involving motor vehicles. This study aims to identify potential injury mechanisms of e-scooter riders involved in frontal impacts against Sports Utility Vehicles (SUVs) using Finite Element Analysis (FEA) and a Human Body Model (HBM). Six impact scenarios at 25 km/h were simulated: on the passenger's side door (1-SD), on the trunk door (2-TD), on the bonnet (3-FB), on the bonnet from the side (4-SB), on the windshield from the side (5-SW), and finally, on the bonnet with an offset (6-FO). A wide range of Injury Risk Criteria (IRCs) was analyzed, including A3MS, HIC15, BrIC, DAMAGE, Cmax and PC Score, and head contact forces were output. Injury Risk Curves were then used to calculate the probability and severity of the sustained injuries predicted by the mentioned IRCs. Overall, the results corresponding to the most injurious scenarios suggested serious (30% to 40% overall probability) and critical (45% probability for the 4-SB scenario) brain, moderate head (30% probability for scenarios 1-SD and 2-TD), and serious thoracic (26% to 78% overall probability) injuries. Additionally, in two scenarios (1-SD and 2-TD), the e-scooter rider's mandible impacted against the vehicle's roof side rail and rear spoiler, involving potential anterior-posterior serious mandible fractures. The conclusions reached in this study help to understand potential injury sources and provide valuable information for the design of specific safety systems or the creation or improvement of e-scooter legislation.

Comparison of rotator cuff to glenoid proximity based on scapulothoracic upward rotation classification

BackgroundRecent evidence suggests that internal impingement, or rotator cuff tendon deformation against the glenoid, occurs during overhead motions and may therefore be a mechanism of pathology even in non-athletes. Clinically, knowing how movement impacts potential injury mechanisms would be useful to guide movement-based treatment strategies. ObjectiveTo compare the distance between the glenoid and rotator cuff footprint between two groups classified based on scapulothoracic upward rotation (UR) magnitude (i.e., low, high) at 90° humerothoracic elevation. MethodsShoulder kinematics were quantified during scapular plane abduction in 60 participants using single-plane fluoroscopy. Of these, 40 were subsequently classified as having high or low scapulothoracic UR based on the sample's distribution. The minimum distance between the glenoid and rotator cuff footprint was calculated along with the locations of closest proximity (i.e., proximity centers). Minimum distances and proximity center locations were compared between groups using 2-factor mixed-model ANOVAs. The prevalence of glenoid-to-footprint contact was also compared. ResultsGlenoid-to-footprint distances consistently decreased as humerothoracic elevation angle increased, and the anterior aspect of the footprint was closest to the posterosuperior glenoid. Minimum distances were not significantly different between UR groups (p≥0.16). However, group differences existed in proximity center locations (p<0.01). Glenoid-to-footprint contact was identified in 75.0% of participants at an average (SD) of 133.6° (3.2°) humerothoracic elevation. ConclusionThe results of this study suggest that decreased UR as classified and assessed in this study does not significantly impact glenoid-to-footprint distances but does alter the location of the contact, which occurred in most participants.

The effect of axillary crutch length on upper limb kinematics during swing-through gait.

Axillary crutches are commonly used in rehabilitation. Inappropriately fit crutches may result in upper limb pain or injury. To investigate the effects of axillary crutch length on upper limb kinematics to better understand potential injury mechanisms. It was hypothesized that crutches that were longer or shorter than standard-fit crutches would alter upper limb kinematics. Cross-sectional. Gait laboratory. Fifteen healthy males with no prior crutch experience. Participants were fit with axillary crutches using standardized methods, as well as with crutches that were 5 cm longer and 5 cm shorter. Participants performed swing-through gait (1.20 ± 0.07 ms-1 ) with all crutch lengths in randomized order. Kinematics were recorded using an optical motion-tracking system and joint angles for the scapula, shoulder, elbow, and wrist were computed. The effects of crutch length on joint range of motion (ROM) and joint angles at initial crutch contact were analyzed using multivariate analysis (Hotelling's T2 ; α=.025) and simultaneous confidence intervals (CI). The long-standard crutch fit comparison showed effects across all joints (ROM p=.009; initial contact p < .001). Longer crutches resulted in greater scapular upward rotation (mean difference [95% CI] ROM: 1.0 [-0.2 to 2.2]; initial contact: -2.7 [-4.4, -1.1]) and shoulder abduction (ROM: 0.8 [-0.1 to 1.8]; initial contact: -1.9 [-4.1 to 0.3]). Crutch length also had effects across all joints for the short-standard fit comparison (ROM p=.004; initial contact p=.016). Shorter crutches resulted in greater scapula downward rotation (2.2 [-0.4 to 4.8]) and greater shoulder adduction (2.5 [-0.6 to 5.6]) at initial contact. Shorter crutches also reduced shoulder flexion/extension ROM (-2.5 [-4.4 to -0.6]). Altered crutch length results in scapular and shoulder kinematic deviations that may present risk factors for upper limb injury with crutch-walking. This may underline the importance of appropriate device fitting to reduce injury risk in crutch users.

Liver Injury and Acute Liver Failure After Bariatric Surgery: An Overview of Potential Injury Mechanisms.

The obesity epidemic has caused a surge in the use of bariatric surgery. Although surgery-induced weight loss is an effective treatment of nonalcoholic fatty liver disease, it may precipitate severe hepatic complications under certain circumstances. Acute liver injury (ALI) and acute liver failure (ALF) following bariatric surgery have been reported in several case series. Although rare, ALI and ALF tend to emerge several months after bariatric surgery. If so, it can result in prolonged hospitalization, may necessitate liver transplantation, and in some cases prove fatal. However, little is known about the risk factors for developing ALI or ALF after bariatric surgery and the mechanisms of liver damage in this context are poorly defined. This review provides an account of the available data on ALI and ALF caused by bariatric surgery, with emphasis on potential injury mechanisms and the outcomes of liver transplantation for ALF after bariatric surgery.

Assessment of brain injury biomechanics in soccer heading using finite element analysis

This study presents an in silico finite element (FE) model-based biomechanical analysis of brain injury metrics and associated risks of a soccer ball impact to the head for aware and unaware athletes, considering ball impact velocity and direction. The analysis presented herein implements a validated soccer ball and 50th percentile human head computational FE model for quantifying traumatic brain injury (TBI) metrics. The brain's mechanical properties are designated using a viscoelastic-viscoplastic constitutive material model for the white and gray matter within the human head FE model. FE results show a dynamic human head-soccer ball peak contact area of approximately seven times greater than those documented for helmet-to-helmet hits in American Football. Due to the deformable nature of the soccer ball, the impact dynamics are unique depending on the location and velocity of impact. TBI injury risks also depend on the location of impact and the impact velocity. Impacts to the rear (BrIC:0.48, HIC15:180.7), side (BrIC:0.52, HIC15:176.5), and front (BrIC:0.37, HIC15:129.0) are associated with the highest injury risks. Furthermore, the FE results indicate when an athlete is aware of an incoming ball, HIC15-based Abbreviated Injury Scale 1 (AIS 1) injury risks for the front, side, and rear impacts decrease from 10.5%, 18.5%, and 19.3%, respectively, to approximately 1% in front and side impacts and under 6% in a rear impact. Lastly, the unique contact area between the head and soccer ball produces pressure gradients in the ball that translate into distinguishable stress waves in the skull and the cerebral cortex. Statement of significanceMild traumatic brain injuries (mTBI) are a worrisome aspect of participation in most sports due to difficulties in their diagnosis in competitions and the potential of long-term neurological defects. These types of injuries are not well understood for athletes playing soccer, specifically pertaining to the risks of heading a soccer ball. Studies are warranted which investigate impacts in this game to improve current knowledge. Our computational study uses finite element modeling to investigate contact between a player's head and the soccer ball. The results of this study present potential injury mechanisms and risks caused by this contact interaction to contribute to the current understanding of brain injuries in soccer and the promotion of athlete safety.

Segment coordination and variability among prospectively injured and uninjured runners

ABSTRACT Coordinative variability (CAV) and underlying coordinative patterns are potential running-related overuse injury (RROI) mechanisms, but prospective analyses are needed. This study compared lower limb CAV and coordinative patterns between prospectively injured and uninjured runners. Knee, shank, and ankle kinematics were collected for 39 recreational runners at the beginning of a 6-month follow-up period. Subjects were classified as injured (n=21) or controls (n=18) based on RROI incidence during follow-up. CAV was quantified using modified vector coding. Time spent in each coordinative pattern category was quantified using binning frequency analysis. Coordinative patterns were classified as mechanically unsound if underlying joint/segment motions opposed anatomically allowable running motion. Wilcoxon Rank-Sum tests compared CAV and binning frequencies between groups within different stance portions for knee-shank, shank-ankle, and knee-ankle couplings (α≤0.05). During initial-stance, the injured group displayed significantly greater knee-ankle CAV (effect size (ES)=1.1), knee-shank CAV (ES=0.97), and greater frequency of mechanically unsound knee-shank (ES=0.72) and shank-ankle (ES=0.63) motion. During mid-stance, the injured group displayed lower frequency of mechanically sound knee-ankle motion (ES=0.31). In late-stance, the injured group displayed greater shank-ankle CAV (ES=0.11). Mechanically unsound coordinative patterns along with greater knee-ankle and shank-ankle CAV potentially lead to RROI.

Exploration of different classes of metrics to characterize motor variability during repetitive symmetric and asymmetric lifting tasks

The substantial kinematic degrees-of-freedom available in human movement lead to inherent variations in a repetitive movement, or motor variability (MV). Growing evidence suggests that characterizing MV permits a better understanding of potential injury mechanisms. Several diverse methods, though, have been used to quantify MV, but limited evidence exists regarding the merits of these methods in the occupational context. In this work, we explored different classes of methods for characterizing MV during symmetric and asymmetric box lifting tasks. Kinematic MV of both the whole-body center-of-mass (COM) and the box were quantified, using metrics derived from a linear method (Standard Deviation), a non-linear method (Sample Entropy; an index of movement regularity), and a novel application of an equifinality method (Goal Equivalent Manifold; an index related to the set of effective motor solutions). Our results suggest that individuals manipulate regularity and the set of effective motor solutions to overcome unwanted motor noises related to the COM. These results, together with earlier evidence, imply that individuals may prioritize stability over variability with increasing task difficulty. Task performance also appeared to deteriorate with decreasing variability and regularity of the COM. We conclude that diverse metrics of MV may be complimentary to reveal differences in MV.

Lower Limb Maneuver Investigation of Chasse Steps Among Male Elite Table Tennis Players.

Background and Objectives: The popularity of table tennis has increased globally. As a result, the biomechanical movement patterns in the lower limb during table tennis have attracted extensive attention from coaches, scientists and athletes. The purpose of this study was to compare the differences between the long and short chasse steps in table tennis and evaluate risk factors related to injuries in the lower limb. Materials and Methods: Twelve male elite athletes performed forehand topspin strokes with long and short chasse steps in this study, respectively. The kinematics data of the lower-limb joints were measured by a Vicon motion analysis system. The electromyograms (EMG) of six lower-limb muscles were recorded using a myoelectricity system. Results: The key findings were that the angle change rate of the ankle in the long chasse step was faster with a larger range of motion (ROM) in the coronal and transverse planes. The hip was also faster in the sagittal and transverse planes but slower in the coronal plane compared with the short chasse step. In addition, the vastus medialis (VM) was the first activated muscle in the chasse step. Conclusions: The hip and ankle joints in the long chasse step and the knee joint in the short chasse step have higher susceptibility to injury. Moreover, tibialis anterior (TA), vastus medialis (VM) and gastrocnemius (GM) should be sufficiently stretched and warmed prior to playing table tennis. The results of this study may provide helpful guidance for teaching strategies and providing an understanding of potential sport injury mechanisms.

Three-Dimensional Takeoff Step Kinetics of Long Jumpers with and without a Transtibial Amputation.

The loads applied on the musculoskeletal system during the long jump takeoff step are not well established for nonamputee athletes or athletes with a lower extremity amputation. Information on joint loading and potential injury mechanisms is important for improving training or rehabilitation protocols, prosthetic design, and the general understanding of the long jump. Three-dimensional takeoff step kinematics and kinetics were used for inverse dynamic model calculations on three male athletes with and seven male athletes without a below the knee amputation (BKA). Athletes with BKA used their affected leg as their takeoff leg. Despite equivalent long jump performance, ground reaction force application characteristics were widely different, and calculated joint loads were significantly lower in athletes with BKA compared with nonamputee athletes during the takeoff step. The takeoff step of the long jump for athletes with BKA seems to be dominated by sagittal plane movements, whereas it involves sagittal plane movement and compensatory joint work in the frontal plane for nonamputee athletes. Coaches and athletes should adapt training protocols to the unique musculoskeletal loading patterns of long jumpers with or without a BKA. Specifically, nonamputee athletes should strengthen the muscles responsible for hip and knee extension, as well as for frontal plane stabilization, early in the season to avoid injuries. The presented data enable clinicians to identify potential causes of pain or injury more differentially in both groups of athletes and might stimulate future research in the field of robotics and prosthetic components. Furthermore, the altered joint mechanics of athletes with BKA versus nonamputees serves as an explanation for their previously described more effective takeoff step.

Chronic Intermittent Hypobaric Hypoxia Attenuates Irradiation Induced Hippocampus Damage in Mice

To observe the manifestations of radiation induced hippocampus damage and the potential injury mechanisms in mice. To examine the protective effects with chronic intermittent hypobaric hypoxia (CIHH) on radiation induced hippocampus damage. A total of 48 male adult C57/BL mice were randomly divided into four groups as control group (group A), CIHH group (group B), irradiation group (group C) and CIHH plus irradiation group (group D). Whole brain irradiation was delivered to them with a single fraction of 10.0Gy. Before radiation, mice in Group B and Group D were treated with CIHH for 28 consecutive days. Thirty days later, the Mirros water maze test was used to evaluate the memory and cognitive function of the mice. Morphological alterations of hippocampal CA1 area were examined by Nissl staining. The expression level of mTOR, Beclin-1, LC3II/I as well as GRP78 and CHOP were quantitatively analyzed by Western blot. The expression of doublecortin (DCX) in the subgranular zone (SGZ) of dentate gyrus (DG) in hippocampus was detected by immunofluorescence to evaluate the neurogenesis. The time of escape latency was increased in group C when compared with group A, whereas it was decreased when compared to group D. The exploration time in the first quadrant within one minute of the mice in group C was significantly reduced than that in group A, the times of cross the platform within one minute was also decreased. The exploration time and the times of cross the platform within one minute were 14.12 ±0.82 S and 2.08 ±0.26 in group D, and were 7.42 ±0.73S and 0.83 ±0.24 times in group C. After irradiation was performed, pathological changes as swelling, nuclear deviation, disorder of cell structure, degeneration and necrosis in neuronal cells of CA1 in hippocampus could be observed by Nissl staining, whereas the damages in hippocampus were ameliorated in group D. In comprison with group A, The levels of GRP78, CHOP, Beclin-1 and LC3II/Iin hippocampus were significantly increased, but the expression of mTOR protein was decreased in group C. When compared with group D, the levels of GRP78, CHOP and mTOR were increased (P < 0.01 for both), and the expression of Beclin-1 and LC3II/Iwere reduced (P < 0.05 for both) in group C. Compared with group A, the expression of DCX in CA1 region of the hippocampus was significantly decreased than that in group C. After pretreatment with CIHH, the expression of it in group D was much higher than that in group C. Irradiation could cause histopathological damage in hippocampus in mice. The potential mechanisms of radiation induced hippocampus damage might be attributed to ER stress and neurogenesis reduction. Simultaneously, irradiation could activate autophagy in hippocampus, which might play a protective role by reducing the damage of ER stress. Pretreated with CIHH could attenuates irradiation induced hippocampus injury by inducting of autophagy as well as increasing the neurogenesis in CA1 region in mice.

Responses and Injuries to PMHS in Side-Facing and Oblique Seats in Horizontal Longitudinal Sled Tests per FAA Emergency Landing Conditions.

The objective of the present exploratory study is to understand occupant responses in oblique and side-facing seats in the aviation environment, which are increasingly installed in modern aircrafts. Sled tests were conducted using intact Post Mortem Human Surrogates (PMHS) seated in custom seats approximating standard aircraft geometry. End conditions were selected to represent candidate aviation seat and restraint configurations. Three-dimensional head center-of-gravity linear accelerations, head angular velocities, and linear accelerations of the T1, T6, and T12 spinous processes, and sacrum were obtained. Three-dimensional kinematics relative to the seat were obtained from retroreflective targets attached to the head, T1, T6, T12, and sacrum. All specimens sustained spinal injuries, although variations existed by vertebral level. While the tension mechanism was associated with cervical spine injuries, complex distraction-coupled with bending and tension was attributed to thoracolumbar spine injuries. Skeletal fractures to the ribcage were attributed to compression induced by the restraint from the seatbelt, the presence of the armrest, and/or severe motions of the unconstrained torso. Pelvic injuries were also attributed to restraint offered by the lap belt on the accelerating torso-pelvis complex in the absence of the armrest. Lower extremity injuries occurred due to the unconstrained motion (flailing mechanism). These results serve as an initial dataset to understand the kinematics of different body regions, injuries and patterns, and potential injury mechanisms describing PMHS responses in the aviation environment.

Neuromechanical synergies in single-leg landing reveal changes in movement control

Our purpose was to examine changes in single-leg landing biomechanics and movement control following alterations in mechanical task demands via external load and landing height. We examined lower-extremity kinematic, kinetic, and electromyographic (EMG) adjustments, as well as changes in movement control from neuromechanical synergies using separate principal component analyses (PCA). Nineteen healthy volunteers (15M, 4F, age: 24.3±4.9y, mass: 78.5±14.7kg, height: 1.73±0.08m) were analyzed among 9 single-leg drop landing trials in each of 6 experimental conditions (3 load and 2 landing height) computed as percentages of subject bodyweight (BW, BW+12.5%, BW+25%) and height (H12.5% & H25%). Condition order was counterbalanced, including: 1.) BW·H12.5, 2.) BW+12.5·H12.5, 3.) BW+25·H12.5, 4.) BW·H25, 5.) BW+12.5·H25, 6.) BW+25·H25. Lower-extremity sagittal joint angles and moments (hip, knee, & ankle), vertical ground reaction force (GRFz), and electrical muscle activity (gluteus maximus, biceps femoris, vastus medialis, medial gastrocnemius, & tibialis anterior muscles), were analyzed in each trial. Biomechanical adjustments and neuromechanical synergies were assessed using PCA. Subjects reduced effective landing height through segmental configuration adjustments at ground contact, extending at the hip and ankle joints with greater load and landing height (p⩽0.028 and p⩽0.013, respectively), while using greater medial gastrocnemius pre-activation with greater load (p⩽0.006). Dimension reduction was observed under greater mechanical task demands, compressing and restructuring synergies among patterns of muscle activation, applied loads, and segmental configurations. These results provide insight into movement control and potential injury mechanisms in landing activities.

Evaluation of the Kinematic Responses and Potential Injury Mechanisms of the Jejunum during Seatbelt Loading.

High-speed biplane x-ray was used to research the kinematics of the small intestine in response to seatbelt loading. Six driver-side 3-point seatbelt simulations were conducted with the lap belt routed superior to the pelvis of six unembalmed human cadavers. Testing was conducted with each cadaver perfused, ventilated, and positioned in a fixed-back configuration with the spine angled 30° from the vertical axis. Four tests were conducted with the cadavers in an inverted position, and two tests were conducted with the cadavers upright. The jejunum was instrumented with radiopaque markers using a minimally-invasive, intraluminal approach without inducing preparation-related damage to the small intestine. Tests were conducted at a target peak lap belt speed of 3 m/s, resulting in peak lap belt loads ranging from 5.4-7.9 kN. Displacement of the radiopaque markers was recorded using high-speed x-ray from two perspectives. Marker trajectories were tracked using motion analysis software and projected into calibrated three-dimensional coordinates to quantify the seatbelt and jejunum kinematics for each test. Five of the six tests resulted in jejunum damage. Based on the autopsy findings and the assessment of the belt and jejunum kinematics, it is likely that direct abdominal interactions with the seatbelt resulting in compression and stretch of the jejunum are components of the mechanisms of crash-induced jejunum injuries. In addition, the presence of fluid or air in the portion of the jejunum in the load path appears to be necessary to create jejunum damage in the cadaver model. Overall, the kinematics and damage data generated in this study may be useful for future restraint system development.

Firefighter injuries are not just a fireground problem.

Linking firefighter injury reporting to general motion patterns may provide insight into potential injury mechanisms and the development of prevention strategies. To characterize the injuries sustained by members of a large Canadian metropolitan fire department over a 5-year span. Data were taken from injury reports filed by career firefighters between 2007 and 2011. Injuries were described by job duty, type, body part affected, and the general motion pattern employed at the time of injury (e.g. lifting). Of the 1311 injuries reported, 64% were categorized as sprains and strains (musculoskeletal disorders -MSDs), themost frequent of which affected the back (32%). Categorized by job duty, 65% of MSDs were sustained while working at the fire station or during physical training-related activities. Only 15% were attributed to fireground operations. Furthermore, the associated job duty could not differentiate the types of injuries sustained; back injuries occurred primarily while lifting, knee injuries while stepping, and shoulder injuries during pushing/pulling-related activities. Firefighter injuries are not just a fireground problem. Injury causation may be better understood by linking the injury location and type with motion patterns rather than job duties. This information could assist in developing general prevention strategies for the fire service.

Nature and etiology of hollow-organ abdominal injuries in frontal crashes

Injuries to the hollow organs of the lower digestive system carry substantial risk of complication due to infection and blood loss, and commonly require invasive abdominal surgery to diagnose and treat. The causes of, and risk factors for, lower abdomen injury in automobile collisions are poorly understood. The goal of this study was to investigate the risk factors and potential mechanisms of hollow-organ, lower abdomen injury in belted automobile occupants in frontal collisions.A field survey data analysis was performed to examine the relationship between various occupant and collision factors and the risk of moderate or greater severity injury (i.e., Abbreviated Injury Scale, AIS 2+) to the small intestine, large intestine, or mesentery among belted occupants involved in frontal collisions. Descriptive and comparative risk factor analyses were performed with data originating from that National Automotive Sampling System Crashworthiness Data System (NASS-CDS) over the years 2000–2011. Multivariable logistic regression models were developed to describe the effects of these factors on hollow-organ injury risk. Potential injury mechanisms were further investigated through in-depth examination of select cases exhibiting hollow-organ injuries from the Crash Investigation Research and Engineering Network (CIREN).The inclusion criteria yielded 25,407 individual cases from NASS-CDS, representing a weighted population of 11,373,358 exposed automobile occupants. Within this dataset, 143 cases (weighted frequency: 7962 occupants) exhibited AIS 2+ injury to hollow abdominal organs. Multivariable regression analysis indicated a statistically significant increased risk of moderate or greater severity injuries to the hollow organs of the abdomen with increased in ΔV (odds ratio (OR) 1.07, 95% confidence interval: 1.06–1.09) and age (OR: 1.03, 1.01–1.06). Albeit non-statistically significant, a positive association between BMI and injury risk was observed, especially among obese individuals (OR: 3.55, 0.82–15.2). No association was observed for gender or seated location within the vehicle. Resultfrom this study indicate that hollow abdominal organ injury is a universal problem in frontal collisions, not confined to a specific gender or seating location. Examination of CIREN cases suggests these types of injuries are associated with direct loading of the lower abdomen by the lap belt, either through poor initial belt positioning or through a “submarining” type of kinematic where the lap belt slips off of the pelvis and loads into the abdomen. Potential countermeasures against hollow-organ abdominal injury should include measures to improve initial lap belt fit, and to retain engagement of the lap belt on the pelvis throughout the collision event.

The Identification of Novel Potential Injury Mechanisms and Candidate Biomarkers in Renal Allograft Rejection by Quantitative Proteomics

Early transplant dysfunction and failure because of immunological and nonimmunological factors still presents a significant clinical problem for transplant recipients. A critical unmet need is the noninvasive detection and prediction of immune injury such that acute injury can be reversed by proactive immunosuppression titration. In this study, we used iTRAQ -based proteomic discovery and targeted ELISA validation to discover and validate candidate urine protein biomarkers from 262 renal allograft recipients with biopsy-confirmed allograft injury. Urine samples were randomly split into a training set of 108 patients and an independent validation set of 154 patients, which comprised the clinical biopsy-confirmed phenotypes of acute rejection (AR) (n = 74), stable graft (STA) (n = 74), chronic allograft injury (CAI) (n = 58), BK virus nephritis (BKVN) (n = 38), nephrotic syndrome (NS) (n = 8), and healthy, normal control (HC) (n = 10). A total of 389 proteins were measured that displayed differential abundances across urine specimens of the injury types (p < 0.05) with a significant finding that SUMO2 (small ubiquitin-related modifier 2) was identified as a "hub" protein for graft injury irrespective of causation. Sixty-nine urine proteins had differences in abundance (p < 0.01) in AR compared with stable graft, of which 12 proteins were up-regulated in AR with a mean fold increase of 2.8. Nine urine proteins were highly specific for AR because of their significant differences (p < 0.01; fold increase >1.5) from all other transplant categories (HLA class II protein HLA-DRB1, KRT14, HIST1H4B, FGG, ACTB, FGB, FGA, KRT7, DPP4). Increased levels of three of these proteins, fibrinogen beta (FGB; p = 0.04), fibrinogen gamma (FGG; p = 0.03), and HLA DRB1 (p = 0.003) were validated by ELISA in AR using an independent sample set. The fibrinogen proteins further segregated AR from BK virus nephritis (FGB p = 0.03, FGG p = 0.02), a finding that supports the utility of monitoring these urinary proteins for the specific and sensitive noninvasive diagnosis of acute renal allograft rejection.

Anticipatory effects on anterior cruciate ligament loading during sidestep cutting

BackgroundA key to understanding potential anterior cruciate ligament injury mechanisms is to determine joint loading characteristics associated with an injury-causing event. However, direct measurement of anterior cruciate ligament loading during athletic tasks is invasive. Thus, previous research has been unable to study the association between neuromuscular variables and anterior cruciate ligament loading. Therefore, the purpose of this study was to determine the influence of movement anticipation on anterior cruciate ligament loading using a musculoskeletal modeling approach. MethodsTwenty healthy recreationally active females were recruited to perform anticipated and unanticipated sidestep cutting. Three-dimensional kinematics and kinetics of the right leg were calculated. Muscle, joint and anterior cruciate ligament forces were then estimated using a musculoskeletal model. Dependent t-tests were conducted to investigate differences between the two cutting conditions. FindingsACL loading significantly increased during unanticipated sidestep cutting (p<0.05). This increase was primarily due to a significant increase in the sagittal plane ACL loading, which contributed 62% of the total loading. Frontal plane ACL loading contributed 26% and transverse plane ACL loading contributed 12%. InterpretationThese results suggest that anterior cruciate ligament loading resulted from a multifaceted interaction of the sagittal plane shear forces (i.e., quadriceps, hamstrings, and tibiofemoral), as well as the frontal and transverse plane knee moments. Additionally, the results of this study confirm the hypothesis in the current literature that unanticipated movements such as sidestep cutting increase anterior cruciate ligament loading.

Knee loading patterns in a simulated netball landing task

The knee is a common site of injury in netball players. In this study, 10 high-performance netball players underwent a biomechanical assessment of their single leg landing technique whilst receiving a pass. Three-dimensional video and ground reaction force data were recorded using a motion analysis system. Net internal knee joint moments were calculated using a rigid body analysis and inverse dynamics. The kinematics of the support leg and front-on video footage was used to investigate whether players adhered to guidelines on safe and effective landing strategies. Results indicated that for most players the internal valgus moment was the largest frontal plane knee moment during the landing phase. This may reflect a relatively greater need to resist varus knee excursion or may be related to the kinematics of the hip. For 6 of the 10 players the rapid change to an internal knee valgus moment coincided with hip adduction. Since an increase in the magnitude of the internal valgus moment may increase the compressive forces in the medial compartment of the knee, further work should be undertaken to determine if a neuromuscular training intervention to improve the strength of the hip musculature may be beneficial for these players. A large relative excursion of the knee compared to the hip may indicate that these players had a greater reliance on the more distal segments of the lower extremity for the attenuation of the ground reaction forces. This information may be used to better understand potential knee injury mechanisms in netball players.