Hybrid Finite-Discrete Element Modelling of Various Rock Fracture Modes during Three Conventional Bending Tests

The numerical techniques for modelling the rock fracture have been briefly reviewed. A hybrid finite-discrete element method (HFDEM) is proposed to simulate various fracture types of rock. A fracture model is implemented in the HFDEM for simulation of the three main fracture types. In addition, the influence of the strain rate is considered during the HFDEM modelling rock behavior. Then, two typical rock mechanism tests are employed to calibrate the HFDEM. The proposed method has well modelled the rock fracture processes and can obtain reasonable stress distribution and force–displacement curves. After that, the HFDEM is used to model three convention bending tests. The obtained rock fracture processes indicates that the HFDEM can simulate various fracture types. The obtained rock strengths and fracture toughness indicate that the HFDEM can reflect the influence of the strain rate. It is concluded that the HFDEM can model the entire and complete rock fracture process during the three convention bending tests, and it also can capture the rock’s behavior on the strain rate.

Comparative study of plating versus conservative treatment in mid shaft fractures of clavicle

<p><strong>Background</strong>: Clavicle fractures represent up to 4% and 1% of all fractures, respectively. Historically, both fracture types have been treated conservatively with acceptable outcomes. The surgical correction of these fractures is currently being investigated as a viable alternative to conservative management.</p><p><strong>Methods</strong>: A systematic search of PubMed was performed to identify articles comparing open reduction and internal fixation (ORIF) with conservative treatment for clavicular fractures. Specific outcomes of interest were shoulder function, pain, strength, range of motion, and risk of non-union. </p><p><strong>Results</strong>: ORIF of midshaft clavicular fractures results in increased shoulder function within 6 weeks following treatment and a decreased risk of non-union. After 1 year, there was no longer a difference in shoulder function between groups. There was no difference in pain between treatment groups. Both ORIF and conservative treatment of extraarticular scapular fractures yield comparable results in shoulder function, range of motion, and strength following treatment.</p><p><strong>Conclusions</strong>: This study, early primary plate fixation of comminuted mid shaft clavicular fractures results in improved patient-oriented outcomes, improved surgeon-oriented outcomes, earlier return to function and decreased rates of non-union and malunion. </p>

Erectile Dysfunction after Conservative Treatment of Sacral Fractures in Males without Injury to the Urinary System

Background This study aimed to determine the incidence of erectile dysfunction (ED) reported by patients, and to define the prognostic relationship between ED and conservatively treated sacral fracture without urethral injury. Methods Patients aged between 20 – 50 years who were sexually active and had no known sexual dysfunction prior to the trauma were included in the study. Seventy-seven patients (47 married, 30 single) treated conservatively for sacral fracture between April 2012 and February 2017 were retrospectively screened. Patients were compared in terms of age, marital status, body mass index (BMI), trauma mechanism, additional system injury, functional outcomes, and complications. Functional outcomes were assessed using the International Index of Erectile Function (IIEF-5) and the Majeed pelvic fracture functional assessment scale (MPS). Results No statistically significant difference was observed between fracture types with respect to age, BMI, follow-up, marital status, trauma mechanism, and accompanying injury. The incidence of ED was 27.3% for those that received conservative treatment after sacrum fracture. The mean score of IIEF-5 was 18.6 ± 6.6 and MPS was 77.2 ± 13.2. There was no significant relationship between the injury type of the patients and the IIEF-5 and MPS scores (p = 0.593 and p = 0.907, respectively). The lowest IIEF-5 score was found in Denis type 2 fractures (p = 0.020). Conclusion The frequency of ED was higher in Denis type 2 sacrum fractures. Sexual function should be questioned in the follow-up, especially in those fracture types.

Displacement of the Greater Tuberosity in Humeral Head Fractures Does Not only Depend on Rotator Cuff Status

It is assumed that dorsocranial displacement of the greater tuberosity in humeral head fractures is caused by rotator cuff traction. The purpose of this study was to investigate the association between rotator cuff status and displacement characteristics of the greater tuberosity in four-part humeral head fractures. Computed tomography scans of 121 patients with Neer type 4 fractures were analyzed. Fatty infiltration of the supra- and infraspinatus muscles was classified according to Goutallier. Position determination of the greater tuberosity fragment was performed in both coronary and axial planes to assess the extent of dorsocranial displacement. Considering non-varus displaced fractures, the extent of the dorsocranial displacement was significantly higher in patients with mostly inconspicuous posterosuperior rotator cuff status compared to advanced fatty degenerated cuffs (cranial displacement: Goutallier 0–1: 6.4 mm ± 4.6 mm vs. Goutallier 2–4: 4.2 mm ± 3.5 mm, p = 0.020; dorsal displacement: Goutallier 0–1: 28.4° ± 32.3° vs. Goutallier 2–4: 13.1° ± 16.1°, p = 0.010). In varus displaced humeral head fractures, no correlation between the displacement of the greater tuberosity and the condition of the posterosuperior rotator cuff could be detected (p ≥ 0.05). The commonly accepted theory of greater tuberosity displacement in humeral head fractures by rotator cuff traction cannot be applied to all fracture types.

Association between Bone Mineral Density and Fracture Characteristics in the 5th Metatarsal Bone Base Fracture in Elderly for Prediction of Osteoporotic Fracture

Background: This study aimed to analyze the correlation between bone mineral density (BMD) and the type of 5th metatarsal fracture, as well as to demonstrate whether there is a difference in radiological findings (heel alignment angle [HAA], heel moment arm [HMA], and metatarsus angle) between fracture types.Methods: A total of 87 patients were enrolled in the study and allocated into 3 groups: the Zone 1 group (N=36), the Zone 2 group (N=33), and the Zone 3 group (N=18). The participants’ demographic data, T-scores, existing fracture or osteoporosis medications, and radiologic parameters including HAA, HMA, and metatarsus adductus angle were analyzed and compared.Results: There was a significant difference between the mean age of the participants, with the highest age in the Zone 1 group and the lowest in the Zone 3 group. Regarding the history of concurrent fracture or osteoporosis medications, there was no significant difference between the 3 groups. Similarly, no significant difference was observed between the 3 groups about the BMD values. In contrast, the HAA was statistically significant in all groups with a positive correlation of -8.9 in the Zone 1 group, a negative correlation of 3.55 in the Zone 2 group, and an inverse relationship of 6.1 in the Zone 3 group. The metatarsus adductus angle was significantly higher in the Zone 3 group than the Zone 1 and Zone 2 groups.Conclusions: The location of a 5th metatarsal bone fracture is not significantly associated with BMD. However, mechanical influences, such as hindfoot varus or forefoot adductus, have a significant correlation with fracture types.

There is a Correlation between Fragility Fractures of the Pelvis and a Circle-Type Morphology of the True Pelvis, but Not with Pelvic Incidence

Purpose: Osteoporosis is a major risk factor for the development of fragility fractures of the pelvis (FFP). There is a lack of information about the influence of anatomical conditions such as Pelvic Incidence and Pelvic Ratio (DT/DS ratio) on this kind of fractures. Methods: This is a monocentric retrospective analysis. X-ray images of the lumbar spine and pelvis and 3D-MPR CT reconstructions of the pelvis were analysed to determine Pelvic Incidence (PI) and Pelvic Ratio (PR) in 141 fragility fractures of the pelvis. Statistical analyses were performed to examine the correlation between these spinopelvic parameters and fragility fractures of the pelvis. Results: A total of 141 fragility fractures of the pelvis (14 men = 9.93%, 127 women = 90.07%) were analysed. According to the FFP-classification we recognized FFP type 1 fractures in 19.15%, FFP type 2 in 41.13%, FFP type 3 in 8.51% and FFP type 4 fractures in 32.21%. The mean PI was 58.83º. There was no statistical correlation between PI and fracture types (p=0.81). The mean PR was 1.099. 57 patients (40.43%) demonstrated a DT/DS ratio ≤ 1.06, corresponding to a circle-type morphology. 24 patients (17.02%) demonstrated a DT/DS ratio ≥ 1.18, corresponding to an ellipse-type pelvis. A circle-type pelvis is significantly more often associated with fragility fractures of the pelvis than an ellipse-type morphology (p<0.001). Conclusion: The results of our work demonstrate a strong statistical correlation between the circle-type morphology of the pelvis (PR ≤ 1.06) and fragility fractures of the pelvis. There is no statistical correlation between fragility fractures of the pelvis and Pelvic Incidence.

Which factors influence treatment decision in fragility fractures of the pelvis? - results of a prospective study

Background The aim of the present study was to describe specific characteristics of patients suffering from pelvic fragility fractures and evaluate factors that might influence treatment decisions which may optimize treatment pathways and patient mobility in the future. Methods A prospective study with patients suffering from fractures of the pelvis and aged 60 years or above was performed between 2012 and 2016. Data acquisition took place at admission, every day during hospitalization and at discharge. Results One hundred thirty-four patients (mean age of 79.93 (± 7.67) years), predominantly female (84%), were included. Eighty-six patients were treated non-operatively. Forty-eight patients underwent a surgical procedure. The main fracture types were B2 fractures (52.24%) and FFP IIb fractures (39.55%). At the time of discharge, pain level (NRS) could be significantly reduced (p < 0.001). Patients who underwent a surgical procedure had a significantly higher pain level on day three and four compared to the non-operative group (p = 0.032 and p = 0.023, respectively). Significant differences were found in the mobility level: patients treated operatively on day four or later were not able to stand or walk on day three as compared to non-operatively treated patients. Regarding B2 fractures, a significantly higher mobility level difference between time of admission and discharge was found in patients treated with a surgical procedure compared to patients treated non-operatively (p = 0.035). Conclusions Fracture type, mobility level and pain level influence the decision to proceed with surgical treatment. Especially patients suffering from B2 fractures benefitted in terms of mobility level at discharge when treated operatively. Level of evidence II

Hip Fracture Confers Significantly Greater Mortality Risk in Older Adults Relative to Other Lower Extremity Fractures (Preprint)

BACKGROUND Hip fracture in older adults is tied to increased mortality risk. Deconvolution of the mortality risk specific to hip fracture from that of various other fracture types has not been performed in recent hip fracture studies, but is critical to determining current unmet needs for therapeutic intervention. OBJECTIVE This study examined whether hip fracture increases the one-year post-fracture mortality rate relative to several other fracture types and determined if dementia or type 2 diabetes (T2D) exacerbates post-fracture mortality risk. METHODS TriNetX Diamond Network data were used to identify elderly patients that suffered a single fracture event of the hip, the upper humerus, or several regions near and distal to the hip between 2010-2019. Propensity-score matching, Kaplan-Meier, and hazard ratio analyses were performed for all fracture groupings relative to hip fracture. One-year post-fracture mortality rates in elderly populations with dementia or T2D were established. RESULTS One-year mortality rates following hip fracture consistently exceeded all other lower extremity fracture groupings as well as the upper humerus. Survival probabilities were dramatically lower in the hip fracture groups even after propensity score-matching cohorts for variety of broad categories of characteristics. Dementia in younger elderly cohorts acted synergistically with hip fracture to exacerbate one-year mortality risk. T2D did not exacerbate one-year mortality risk beyond mere additive effects. CONCLUSIONS Elderly patients post-hip fracture have a significantly decreased survival probability. Greatly increased one-year mortality rates following hip fracture may arise from differences in bone quality, bone density, trauma, concomitant fractures, post-fracture treatments or diagnoses, restoration of pre-fracture mobility, or a combination thereof. The synergistic effect of dementia may suggest detrimental mechanistic or behavioral combinations between these two comorbidities Renewed efforts should focus on modulating the mechanisms behind this heightened mortality risk, with particular attention to mobility and comorbid dementia.

Bone morphological feature extraction for customized bone plate design

Fractures are difficult to treat because of individual differences in bone morphology and fracture types. Compared to serialized bone plates, the use of customized plates significantly improves the fracture healing process. However, designing custom plates often requires the extraction of skeletal morphology, which is a complex and time-consuming procedure. This study proposes a method for extracting bone morphological features to facilitate customized plate designs. The customized plate design involves three major steps: extracting the morphological features of the bone, representing the undersurface features of the plate, and constructing the customized plate. Among these steps, constructing the undersurface feature involves integrating a group of bone features with different anatomical morphologies into a semantic feature parameter set of the plate feature. The undersurface feature encapsulates the plate and bone features into a highly cohesive generic feature and then establishes an internal correlation between the plate and bone features. Using the femoral plate as an example, we further examined the validity and feasibility of the proposed method. The experimental results demonstrate that the proposed method improves the convenience of redesign through the intuitive editing of semantic parameters. In addition, the proposed method significantly improves the design efficiency and reduces the required design time.