Dataset Information

Femur loading in feet-first fall experiments using an anthropomorphic test device.

ABSTRACT: BACKGROUND:Femur fractures are a common orthopedic injury in young children. Falls account for a large portion of accidental femur fractures in young children, but there is also a high prevalence of femur fractures in child abuse, with falls often provided as false histories. Objective information regarding fracture potential in short distance fall scenarios may aid in assessing whether a child's injuries are the result of abuse or an accidental fall. Knowledge of femur loading is the first step towards understanding likelihood of fracture in a fall. OBJECTIVE:Characterize femur loading during feet-first free falls using a surrogate representing a 12-month-old child. METHODS:The femur and hip joint of a surrogate representing a 12-month-old were modified to improve biofidelity and measure femur loading; 6-axis load cells were integrated into the proximal and distal femur. Femur modification was based upon CT imaging of cadaveric femurs in children 10-14 months of age. Using the modified 12-month-old surrogate, feet-first free falls from 69?cm and 119?cm heights onto padded carpet and linoleum were conducted to assess fall dynamics and determine femur loading. Femur compression, bending moment, shear and torsional moment were measured for each fall. RESULTS:Fall dynamics differed across fall heights, but did not substantially differ by impact surface type. Significant differences were found in all loading conditions across fall heights, while only compression and bending loads differed between carpet and linoleum surfaces. Maximum compression, bending, torsion and shear occurred in 119?cm falls and were 572?N, 23?N-m, 11?N-m and 281?N, respectively. CONCLUSIONS:Fall dynamics play an important role in the biomechanical assessment of falls. Fall height was found to influence both fall dynamics and femur loading, while impact surface affected only compression and bending in feet-first falls; fall dynamics did not differ across carpet and linoleum. Improved pediatric thresholds are necessary to predict likelihood of fracture, but morphologically accurate representation of the lower extremity, along with accurate characterization of loading in falls are a crucial first step.

SUBMITTER: Thompson A

PROVIDER: S-EPMC6070421 | biostudies-literature | 2018 Aug

REPOSITORIES: biostudies-literature

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Femur loading in feet-first fall experiments using an anthropomorphic test device.

Thompson Angela A Bertocci Gina G Smalley Craig C

Journal of forensic and legal medicine 20180331

<h4>Background</h4>Femur fractures are a common orthopedic injury in young children. Falls account for a large portion of accidental femur fractures in young children, but there is also a high prevalence of femur fractures in child abuse, with falls often provided as false histories. Objective information regarding fracture potential in short distance fall scenarios may aid in assessing whether a child's injuries are the result of abuse or an accidental fall. Knowledge of femur loading is the fi ...[more]

PMID: 29680494

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Project description:Physical activity enhances proximal femur bone mass, but it remains unclear whether the benefits translate into an enhanced ability to resist fracture related loading. We recently used baseball pitchers as a within-subject controlled model to demonstrate physical activity induced proximal femur adaptation in regions associated with weight bearing and increased strength under single-leg stance loading. However, there was no measurable benefit to resisting common injurious loading (e.g. a fall onto the greater trochanter). A lack of power and a small physical activity effect size may have contributed to the latter null finding. Softball pitchers represent an alternative within-subject controlled model to explore adaptation of the proximal femur to physical activity, exhibiting greater dominant-to-nondominant (D-to-ND) leg differences than baseball pitchers. The current study used quantitative computed tomography, statistical parametric mapping, and subject-specific finite element (FE) modeling to explore adaptation of the proximal femur to physical activity in female softball pitchers (n = 25). Female cross-country runners (n = 15) were included as symmetrically loaded controls, showing very limited D-to-ND leg differences. Softball pitchers had D-to-ND leg differences in proximal femur, femoral neck, and trochanteric volumetric bone mineral density and content, and femoral neck volume. Voxel-based morphometry analyses and cortical bone mapping showed D-to-ND leg differences within a large region connecting the superior femoral head, inferior femoral neck and medial intertrochanteric region, and within the greater trochanter. FE modeling revealed pitchers had 19.4% (95%CI, 15.0 to 23.9%) and 4.9% (95%CI, 1.7 to 8.2%) D-to-ND leg differences in predicted ultimate strength under single-leg stance loading and a fall onto the greater trochanter, respectively. These data affirm the spatial and strength adaptation of the proximal femur to weight bearing directed loading and demonstrate that the changes can also have benefits, albeit smaller, on resisting loads associated with a sideways fall onto the greater trochanter.

Project description:Growing animals should allocate their limited resources in ways that maximize survival. Seabird chicks must balance the growth of features and fat reserves needed to survive on land with those needed to successfully fledge and survive at sea. We used a large, 34-year dataset to examine energy allocation in Magellanic penguin chicks. Based on the temporal trends in the selective pressures that chicks faced, we developed predictions relating to the timing of skeletal feature growth (Prediction 1), variation in skeletal feature size and shape (Prediction 2), and responses to periods of high energetic constraint (Prediction 3). We tested our predictions using descriptive statistics, generalized additive models, and principal component analysis. Nearly all of our predictions were supported. Chicks grew their feet first, then their flippers. They continued to grow their bill after fledging (Prediction 1). Variance in feature size increased in young chicks but declined before fledging; this variance was largely driven by overall size rather than by shape (Prediction 2). Chicks that died grew slower and varied more in feature size than those that fledged (Prediction 2). Skeletal features grew rapidly prior to thermoregulation and feet and flippers were 90% grown prior to juvenile feather growth; both thermoregulation and feather growth are energetically expensive (Prediction 3). To avoid starvation, chicks prioritized storing mass during the first 10 days after hatching; then, the body condition of chicks began to decline (Prediction 3). In contrast to our prediction of mass prioritization in young chicks, chicks that were relatively light for their age had high skeletal size to mass ratios. Chicks did not show evidence of reaching physiological growth limits (Prediction 3). By examining energy allocation patterns at fine temporal scales and in the context of detailed natural history data, we provide insight into the trade-offs faced by growing animals.

Project description:BackgroundFemur fracture is a major burden among elderly people, leading patients to be bedridden for a long time in the hospital. The body is more likely to be in a catabolic state as a result of the prolonged fasting period required for surgery, leading to an increase in insulin resistance. Pre-operative carbohydrate loading has been shown to improve postoperative outcomes in several countries. The study aimed to evaluate the effect of pre-operative carbohydrate loading in femur fracture surgery.MethodsThis study was single-center, hospital-based, open-label, parallel-group randomized controlled trial conducted between August 2020 and November 2021. A total of 66 participants, aged 50 years and above having femur fractures planned for surgery were included in this study and assigned to the control (n = 33) and study (n = 33) groups through computer-generated random numbers. The control group was kept fasting from midnight to the next morning as in existence while the study group was intervened with carbohydrate loading according to the Enhanced Recovery After Surgery (ERAS) protocol. The pre-operative nutritional status was identified and the postoperative outcomes were measured using the Visual Analogue Score (VAS), Cumulative Ambulatory Score (CAS), and Modified Barthel Index (MBI) scoring systems. Statistical analyses were performed using the Chi-square test and the Student's two-sample t-test to compare the outcomes between the two groups.ResultsAll the participants completed the study. There was a significant reduction in the average postoperative pain in the carbohydrate loading group (VAS: 4.8 (SD ± 1.8), 95% CI: 4.7-5.4) as compared to the control group (VAS: 6.1 (SD ± 2.1), 95% CI: 5.3-6.8). The average CAS showed a significant improvement in regaining the mobility function of participants in the study group (CAS: 8.1 (SD ± 2.8), 95% CI: 7.1-9.1) than that of the control group (CAS: 6.8 (SD ± 2.8), 95% CI: 5.8-7.8). The mean MBI score of the participants at the time of discharge from the hospital was higher in the study group (MBI:13.1 (SD ± 2.3), 95% CI: 12.2-13.9) compared to the control group (MBI: 11.8 (SD ± 3.1), 95% CI:10.6-12.9). Similarly, the length of hospital stay after surgery had decreased in the study group than in the control group.ConclusionsThe uptake of carbohydrate loading showed reduced post-operative pain, enhanced functional mobility, and decreased length of hospital stay. This study warrants larger trials to show the effect of pre-operative carbohydrate loading in a clinical setting.Trial registrationNCT04838366, first registered on 09/042021 ( https://clinicaltrials.gov/ct2/show/NCT04838366 ).

Dataset Information

Femur loading in feet-first fall experiments using an anthropomorphic test device.

Publications

Femur loading in feet-first fall experiments using an anthropomorphic test device.

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