Radiographic outcomes and non-union factor analysis in fragmentary segmental femoral shaft fractures (AO/OTA 32C3) treated with reamed antegrade nailing.

This study retrospectively assessed radiographic outcomes and risk factors associated with non-union in femoral shaft fragmentary segmental fractures (AO/OTA 32C3) treated with reamed antegrade intra-medullary nailing. Radiological outcomes, including union and alignment, were evaluated. The risk factors for non-union were investigated, including demographics and treatment-related characteristics, such as the number of interlocking screws, segmentation length, main third fragment length, distance of the main third fragment, width ratio and exposed nail length in one cortex from immediate post-operative radiographs. Multivariate logistic regression was used for statistical analysis. Among 2295 femoral shaft fracture patients from three level-1 trauma centers, 51 met the inclusion criteria. The radiological union was achieved in 37 patients (73%) with a mean union time of 10.7 ± 4.8 months. The acceptable axial alignment was observed in 30 patients (59%). Multiple logistic regression analysis identified only exposed nail length as a significant risk factor for non-union (odds ratio: 1.599, p = 0.003) and the cut-off value was 19.1 mm (sensitivity, 0.786; specificity, 0.811). The study revealed high rates of non-union (27%) and malalignment (41%). Therefore, patients who underwent intramedullary nailing with an exposed nail length greater than 19.1 mm or about twice the nail diameter should be cautioned of the potential non-union.

Superior gluteal artery injury in pelvic ring injury and acetabular fracture: Single center observational study.

BACKGROUND: Intrapelvic hemorrhage following pelvic fractures, including pelvic ring and acetabular fractures, originates from the venous system and the fracture. Arterial injury often causes significant bleeding and hemodynamic instability. The superior gluteal artery (SGA) is a frequently injured artery in patients with pelvic fractures. This study investigated the incidence and pattern of SGA injuries associated with pelvic fractures. METHODS: We retrospectively reviewed the medical records of patients with pelvic fractures who visited our institution between January 2016 and April 2022. Patients who underwent angiography for suspected arterial injury and SGA embolization were identified. Furthermore, the demographics and patterns of pelvic fractures were evaluated. RESULTS: In total, 2042 patients with pelvic fractures visited our trauma emergency department and 498 patients (24.4%) underwent embolization for arterial injuries. Of these, 30 patients (1.5% of the total and 6.0% of the patients who underwent procedures) received embolization therapy of the main trunk of the SGA. The mean age of patients was 51.2 (23-85 years), and the injury mechanisms were all high-energy injuries. There were 19 pelvic ring injuries, eight acetabular fractures, and three combined injuries. Acetabular fractures involved mostly both columns. The three combined injuries were lateral compression involving both columns, vertical shear involving both columns, and lateral compression with T-type fractures. Twelve (40.0%) occurred through the sciatic notch of different patterns. CONCLUSIONS: SGA injury occurred in 1.5% of all pelvic fractures and was identified in 6% of patients receiving embolization. SGA injury occurs through various injury mechanisms and fracture patterns, even in the absence of a fracture in the sciatic notch. However, no conclusions could be drawn in this study on the association between SGA injuries, injury mechanisms, and fracture patterns. Since the prediction of SGA injury by fracture pattern is limited, angiography should be performed regardless of fracture pattern when an injury is suspected.

Comparison of Cephalomedullary Nails with Sliding Hip Screws in Surgical Treatment of Intertrochanteric Fractures: A Cumulative Meta-Analysis of Randomized Controlled Trials.

Background: The primary objective of the present study was to compare surgical failures of intertrochanteric fractures of the femur through a meta-analysis of randomized controlled trials and to assess the change in surgical outcomes over time in a cumulative meta-analysis. Methods: To identify studies evaluating the surgical outcomes of internal fixation using sliding hip screws (SHS) or cephalomedullary (CM) nails for the treatment of intertrochanteric fractures of the femur, all records until August 2021 in the PubMed, Embase, and Cochrane Library databases were searched. Studies with the following characteristics were considered eligible: patients who had an intertrochanteric fracture of the femur (population); patients who received surgical treatment using a CM nail (intervention); patients who received surgical treatment using SHS (comparator); surgical failures that required reoperation, including cut-out or cut-through of lag screws, varus collapse or posterior angulation of proximal fragments, loosening of lag screws or helical blades, and fracture nonunion (outcomes); and two reviewers independently reviewed the titles and abstracts of the randomized controlled trials and selected relevant studies for a full-text review (study design). Results: Twenty-one studies were included in the final analysis consisting of 1,777 cases in the SHS group and 1,804 cases in the CM nail group. The cumulative standard mean difference was 0.87, indicating that CM nails had no significant effect in improving the surgical outcomes. There was no significant difference in surgical failure between SHS and CM nails for all intertrochanteric fractures (odds ratio [OR], 1.07; 95% confidence interval [CI], 0.76-1.49). Pooled data showed no significant difference between the two groups in terms of surgical failure in unstable intertrochanteric fractures (OR, 0.80; 95% CI, 0.42-1.54). Conclusions: Although the use of CM nails has become a current trend in the treatment of intertrochanteric fractures, there is no literature supporting their clinical superiority when compared with SHS.

Coronal plane femoral bowing in Far East Asians: implications for the strategy of distal femoral resection in total knee arthroplasty.

BACKGROUND: The accuracy of distal femoral resection in intramedullary (IM) guided total knee arthroplasty (TKA) depends on femoral morphology and varies according to individual anatomy. This study aimed to characterise coronal plane femoral bowing in Far East Asians according to age, sex, and severity of varus deformity to identify optimal strategies for distal femoral resection in TKA. METHOD: Femoral anatomical parameters in 656 patients (M/F = 232:424) were assessed using standing long-leg anteroposterior radiography which was fulfilling strict standard. The femur was divided into three longitudinal segments to measure the segmental anatomical axial deviation from the mechanical axis and intersegmental bowing. Coronal plane femoral bowing pattern was categorised based on combined gross bowing and distal bowing. RESULTS: Mean hip-knee-ankle angle; neck-shaft angle; proximal, middle, and distal segmental axial differences; mechanical lateral distal femoral angle; and femur length were 6.7 ± 6.8°, 125.0 ± 5.5°, 5.9 ± 1.7°, 6.1 ± 1.1°, 5.3 ± 1.6°, 88.4 ± 2.6°, and 432.3 ± 23.9 mm in male and 8.4 ± 5.5°, 126.4 ± 5.6°, 5.4 ± 1.5°, 6.6 ± 0.9°, 5.6 ± 1.6°, 89.3 ± 2.6°, and 410.6 ± 23.3 mm in female, respectively. Mean proximal, distal, and gross femoral bowing was 0.3 ± 1.8°, - 0.8 ± 1.8°, and - 0.5 ± 2.9° in male and 1.2 ± 1.6°, - 1.0 ± 1.6°, and 0.2 ± 2.7° in female, respectively. CONCLUSIONS: Grossly straight femur with a straight distal part was the most common femoral bowing pattern in Far East Asians. Distal bowing was proved to be a key factor to choose method for distal femoral resection in TKA. Using IM-guide to achieve accurate distal femoral resection in the femora with distal segmental axial deviation between 4-8° and distal bowing less than ± 1° is considered feasible.

The difference in the corridor of the antegrade posterior column screw according to the presence of pelvic dysmorphism.

INTRODUCTION: Antegrade posterior column screw (aPCS) fixation via the anterior approach has been widely used for separated the posterior columns in acetabular fracture treatment. Although the relationship between pelvic dysmorphism and sacroiliac screws has been widely studied, no studies have reported on the clinical impact of pelvic dysmorphism on acetabular fractures. This study aimed to reveal the difference in the insertion angle and entry point of aPCS between the dysmorphic and normal pelvises. METHODS: Patients diagnosed with unilateral acetabular fractures and who underwent pelvic computed tomography scans between 2013 and 2019 in two institutes were enrolled in this study. Patients were divided into the dysmorphic and control groups according to the sacral dysmorphic score, which predicts the presence of pelvic dysmorphism, and each group enrolled 130 patients. The semitransparent 3D hemipelvis model was reconstructed using a 3D reconstruction program. The sagittal and coronal angles of a virtual cylinder that fill the safe corridor of the column screw the most were measured. The surface area of the safe corridor and distance of the optimal entry point from the anterior border of the sacroiliac joint were analyzed. The measurements were compared between the dysmorphic and control groups. RESULTS: The average sacral dysmorphic score in the normal and dysmorphic pelvis groups was 56.1 and 81.0, respectively. There were no significant differences in demographic data, including age, sex, height, weight, and body mass index, between the dysmorphic and control groups. There was a significant difference in the average sagittal insertion angle of PCs, which was 38.3° in the control group and 27.2° in the dysmorphic group (P < 0.001). The coronal insertion angles were not significantly different. The dysmorphic group presented longer straight distances (25.9 vs 24.8 mm, P = 0.026) and had a smaller aPCS surface area (685 vs 757 mm2, P < 0.001) than the control group. CONCLUSION: The present study describes a difference in the corridor of aPCS between the dysmorphic and normal pelvis. Insertion of aPCS in the dysmorphic pelvis requires a more acute angular trajectory in the sagittal plane than that in the normal pelvis.

Advantages and limitations of intramedullary nailing for the surgical treatment of ipsilateral intertrochanteric and femoral shaft fractures: a retrospective comparative study based on propensity score matching.

INTRODUCTION: The aim of the present study was to introduce surgical technique using long PFNA for the treatment of ipsilateral intertrochanteric and femoral shaft fractures, and evaluate the characteristics of this fracture by comparing its surgical outcomes with those of isolated intertrochanteric and femoral shaft fractures. MATERIALS AND METHODS: Between March 2013 and December 2018, 38 patients with ipsilateral intertrochanteric and femoral shaft fracture were identified at two institutions. Twenty-eight patients with ipsilateral intertrochanteric and femoral shaft fractures were enrolled in the present study. After propensity score matching, fifty-six patients with isolated intertrochanteric (group B) and femoral shaft (group C) fractures were finally enrolled in the present study for 1:2 matching to compare surgical outcomes to that of ipsilateral intertrochanteric and femoral shaft fractures (Group A). RESULTS: All 28 patients achieved union of intertrochanteric fractures, while two experienced non-union of femoral shaft fractures. The union time of intertrochanteric fractures in group A was significantly shorter than that in group B. The union time of femoral shaft fractures in group A was significantly longer than that in group C. CONCLUSIONS: The surgical treatment of ipsilateral intertrochanteric and femoral shaft fractures using long PFNA was advantageous as it allowed both fractures on the same femur to be fixed in one go and showed good surgical outcomes. However, fixation of femoral shaft fractures might be insufficient depending on the fracture level and configuration, and can be a cause of hypertrophic non-union.

Does transarterial pelvic embolization have a negative effect on perioperative outcomes in pelvic ring injury and acetabular fracture?

OBJECTIVE: The purpose of this study was to determine whether TAE negatively impacted perioperative outcomes in patients who underwent open surgery for pelvic trauma. METHODS: We retrospectively reviewed the medical records and radiographs of patients who had open surgery for an acute pelvic trauma between February 2014 and May 2017. The patients were classified into two groups: those who underwent TAE and those who did not. We evaluated preoperative demographics and perioperative outcomes between the two groups. Injury type-specific comparisons were also performed. RESULTS: A total of 136 patients (50 TAE and 86 non-TAE) were included in this study. There were significant differences in preoperative demographics including the type of injury, injury severity score, revised trauma score, surgical approach, initial blood pressure, and the amount of transfusion within 24 h between the two groups. However, no differences in perioperative outcomes were identified except for the amount of total transfusion. There were significant differences between the two groups in the injury type-specific comparisons, specifically in the amount of transfusion within 24 h in patients with pelvic ring injury and in the injury severity score in patients with acetabular fracture. However, there was no difference in perioperative outcomes between the groups for either injury type. CONCLUSION: In the present study, we were unable to identify negative effects of TAE on perioperative outcomes. Therefore, when considering open surgery subsequent to TAE, there is no evidence of increased risk for negative perioperative outcomes, especially with respect to bone healing and deep infection.

Scattering and clustering the proximal screw construct in unilateral locking plate osteosynthesis of distal femoral fractures.

INTRODUCTION: The importance of fixation construct in locking compression plate (LCP) is not well enlightened until recently. The aim of this study was to investigate radiological and clinical outcomes of scattering and clustering of the proximal screw fixation construct in unilateral LCP treatment of the distal femoral fractures. MATERIALS AND METHODS: Patients who were treated for distal femoral fractures using unilateral LCP between January 2014 and December 2019 in our institute were included in this retrospective study. They were divided into groups 1 (35 cases, scattered proximal screw fixation) and 2 (35 cases, clustered proximal screw fixation). Mean follow-up period was 23.6 months for group 1 and 21.3 months for group 2. Medical history, patient demographics, injury characteristics, and surgical characteristics were reviewed and analyzed. Radiological findings including time to callus formation, bridging callus formation, union, and symmetry of the union were assessed and compared between the groups. Clinical outcomes included total blood loss during the operation, postoperative range of motion, and number of revision surgery. RESULTS: The time for callus formation (5.8 weeks in group 1 vs. 4.1 weeks in group 2, p = 0.009) and bridging callus formation (12.5 weeks in group 1 vs. 10.7 weeks in group 2, p = 0.009) was significantly earlier in group 2. Despite similar union rates between groups, the mean time for radiological union was longer in group 2 (10.7 vs 7.4 months, p = 0.001). Though statistically insignificant, more asymmetric union was observed in group 2 (17 vs 11 cases). CONCLUSIONS: Despite a delay in initial callus and bridging callus formation, scattering the proximal screws was better in achieving earlier and more balanced radiographic union than the clustered fixation. We recommend to avoid bridging more than five holes in the whole plate fixation construct to lessen the asymmetric callus formation and to prevent eventual plate breakage.

Relationship between door-to-embolization time and clinical outcomes after transarterial embolization in trauma patients with complex pelvic fracture.

BACKGROUND: While transarterial embolization (TAE) is an effective way to control arterial bleeding associated with pelvic fracture, the clinical outcomes according to door-to-embolization (DTE) time are unclear. This study investigated how DTE time affects outcomes in patients with severe pelvic fracture. METHODS: Using a trauma database between November 1, 2015 and December 31, 2019, trauma patients undergoing TAE were retrospectively reviewed. The final study population included 192 patients treated with TAE. The relationships between DTE time and patients' outcomes were evaluated. Multiple binomial logistic regression analyses, multiple linear regression analyses, and Cox hazard proportional regression analyses were performed to estimate the impacts of DTE time on clinical outcomes. RESULTS: The median DTE time was 150 min (interquartile range, 121-184). The mortality rates in the first 24 h and overall were 3.7% and 14.6%, respectively. DTE time served as an independent risk factor for mortality in the first 24 h (adjusted odds ratio = 2.00, 95% confidence interval [CI] = 1.20-3.34, p = 0.008). In Cox proportional hazards regression analyses, the adjusted hazard ratio of DTE time for mortality at 28 days was 1.24 (95% CI = 1.04-1.47, p = 0.014). In addition, there was a positive relationship between DTE time and requirement for packed red blood cell transfusion during the initial 24 h and a negative relationship between DTE time and ICU-free days to day 28. CONCLUSION: Shorter DTE time was associated with better survival in the first 24 h, as well as other clinical outcomes, in patients with complex pelvic fracture who underwent TAE. Efforts to minimize DTE time are recommended to improve the clinical outcomes in patients with pelvic fracture treated with TAE.

Importance of firm isthmic fixation in high-energy induced subtrochanteric fracture of the femur: retrospective observational study in a level I trauma center.

INTRODUCTION: This study aimed to report the surgical outcomes in patients with high-energy induced subtrochanteric fracture and determine the risk factors for nonunion using statistical analysis. METHODS: This study evaluated 88 patients with high-energy induced subtrochanteric fractures who underwent surgeries with indirect reduction technique and intramedullary nailing between March 2015 and December 2020. Outcome measures, including union time and nonunion incidence, were assessed by radiologic evaluation. Multiple logistic regression analyses were performed to identify the risk factors for nonunion, using age, sex, injury severity score, body mass index, preoperative mobility score, implant, and isthmic fixation as covariates. RESULTS: Five nonunions and two delayed unions were identified. The average union time was 17.4 weeks. Multiple logistic regression analyses showed that poor isthmic fixation was the only risk factor for nonunion (odds ratio 15.294, 95% confidence interval 1.603-145.894, P value 0.018). Out of five nonunion cases, four were confirmed as hypertrophic, and one was confirmed as atrophic. CONCLUSION: Although surgical treatment using an indirect reduction technique and intramedullary nailing showed good outcomes, hypertrophic nonunion due to distal instability could occur if a firm fixation at the level of the isthmus cannot be achieved. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Strain hardening recovery mediated by coherent precipitates in lightweight steel.

We investigated the effect of κ-carbide precipitates on the strain hardening behavior of aged Fe-Mn-Al-C alloys by microstructure analysis. The κ-carbides-strengthened Fe-Mn-Al-C alloys exhibited a superior strength-ductility balance enabled by the recovery of the strain hardening rate. To understand the relation between the κ-carbides and strain hardening recovery, dislocation gliding in the aged alloys during plastic deformation was analyzed through in situ tensile transmission electron microscopy (TEM). The in situ TEM results confirmed the particle shearing mechanism leads to planar dislocation gliding. During deformation of the 100 h-aged alloy, some gliding dislocations were strongly pinned by the large κ-carbide blocks and were prone to cross-slip, leading to the activation of multiple slip systems. The abrupt decline in the dislocation mean free path was attributed to the activation of multiple slip systems, resulting in the rapid saturation of the strain hardening recovery. It is concluded that the planar dislocation glide and sequential activation of slip systems are key to induce strain hardening recovery in polycrystalline metals. Thus, if a microstructure is designed such that dislocations glide in a planar manner, the strain hardening recovery could be utilized to obtain enhanced mechanical properties of the material.

Is open bone graft always necessary when treating aseptic subtrochanteric nonunion with a reamed intramedullary nail?

BACKGROUND: This study aimed to compare the radiological results between closed nailing without bone graft (BG) and open nailing with BG for aseptic subtrochanteric nonunion and to determine when an open procedure with BG should be considered. METHODS: In this retrospective study, we investigated patients who underwent surgical intervention for subtrochanteric nonunion between January 2008 and March 2018 in two institutions. Patients with infection, large bone defect, pathologic fracture, open fracture, previous surgery using plate, and follow-up of less than 1 year were excluded. We compared the demographic details and radiological results between patients who underwent the open procedure with BG (BG group) and the closed procedure without BG (non-BG group) as a historical control, and risk factors for the failure of revision surgery were evaluated. RESULTS: Thirty-seven patients met the criteria and were divided into the following two groups: the BG group (n=19) who underwent open nailing with BG and the non-BG group (n=18) who underwent closed reamed nailing without BG. The mean degrees of correction of varus and flexion deformity were significantly different (p=0.001, respectively), 6.2° and 2.9° in the BG group and 4.1° and 0.6° in the non-BG group, respectively. Bony union was observed in 17 cases (89.5%) in an average of 7.4 months in the BG group and in 16 cases (88.9%) in 7.6 months in the non-BG group, with no significant differences. The factors that were significantly associated with failure of revision were atypical fracture, two or more previous surgeries, and varus and sagittal anterior angulation. CONCLUSIONS: The radiological results of closed reamed nailing without BG for subtrochanteric nonunion were satisfactory. In the effort of percutaneous realignment, gap reduction, and intramedullary reaming, the radiological results of closed nailing without BG were not different from those of open nailing with BG; therefore, closed procedure without BG may be an acceptable option in appropriately selected patients.

Surgical outcomes of transverse acetabular fractures and risk factors for poor outcomes.

BACKGROUND: Transverse acetabular fractures, although classified as elementary, have worse outcomes than other types of acetabular fractures. Prognostic factors for this fracture type are not clearly established. This study aimed to assess the surgical outcomes of transverse acetabular fractures and subtypes thereof and to investigate the prognostic factors. METHODS: Between 2014 and 2019, 39 patients (39 hips) had transverse fractures or subtypes thereof. We reviewed the surgical outcomes and evaluated patient factors, injury factors, and surgical factors in relation to osteoarthritis (OA) and conversion to total hip arthroplasty (THA). Additionally, we analyzed the cutoff values for postoperative residual gaps and steps. RESULTS: Twenty-three male patients and sixteen female with a mean age of 41.7 years (range, 18-78 years) were included. There were 29 satisfactory reductions (74.4%). Eleven hips (28.2%) developed OA, and five (12.8%) of them underwent THA. Dome impaction (odds ratio [OR], 41.173; 95% confidence interval [CI], 1.804-939.814; p = 0.020) and residual gaps (OR, 4.251; 95% CI, 1.248-14.479; p = 0.021) were correlated with poor outcomes. Residual gaps (≥3 mm) and residual steps (≥1 mm) were significantly associated with OA. CONCLUSIONS: Relatively poor reduction was found for transverse acetabular fractures and subtypes thereof. However, the rates of OA and conversion to THA were not high. Dome impaction and wide residual gaps were identified as risk factors for poor outcomes. The development of OA significantly increased if residual gap and step were more than 3 mm and 1 mm, respectively.

Hammock plating for comminuted inferior sleeve avulsion fractures of the patella: A surgical technique and clinical results.

Comminuted inferior sleeve avulsion fractures of the patella is a surgical challenge owing to the lack of directly purchasable bone fragments and the vulnerable patellar tendon below the displaced lip fragments. Despite the reports of various techniques to treat this fracture, still there is need for a new surgical technique to improve the reduction construct. The purpose of this article is to introduce Hammock plating, which is a surgical technique for comminuted inferior sleeve avulsion patella fractures that utilizes synthetic suture and a low-profile mini plate. The reduction construct provides an indirect reduction of the inferior sleeve fragments to form a hammock-like construct that embraces and lifts the lip fragments upward altogether that enables a firm bone-to-bone union. The advantages also include relatively simple and easy procedure with less injury to the fractured bone fragments and patellar tendon.

Traumatic Tricuspid Regurgitation Treated by the Minimally Invasive Double Orifice Technique.

A 37-year-old man was transferred to our level I trauma center after a road traffic accident, presenting with right acetabular fracture, multiple rib fractures, epidural hemorrhage, and liver contusion. Severe traumatic tricuspid regurgitation was also discovered during the work-up for surgery. Our initial attempt at acetabular surgery failed when the patient experienced near cardiac arrest during anesthetic induction. It was hence decided that tricuspid valve repair should precede orthopedic surgery. Minimally invasive tricuspid valve repair using the double orifice technique was successfully performed. Subsequently, acetabular surgery was performed and he was discharged 35 days post-trauma without any complications.

Transarterial embolisation is associated with improved survival in patients with pelvic fracture: propensity score matching analyses.

INTRODUCTION: Transarterial embolisation (TAE) is an effective intervention for management of arterial haemorrhage associated with pelvic fracture. However, its effects on survival and clinical outcomes are unclear. METHODS: Trauma patients with survival data between November 2015 and December 2019 were identified using a trauma database. Patients were divided between TAE and non-TAE groups, and a propensity score was developed using multivariate logistic regression. Survival at 28 days was compared between the groups after propensity score matching. RESULTS: Among 881 patients included in this study, 308 (35.0%) were treated with TAE. After propensity score matching, 130 pairs were selected. Survival at 28 days was significantly higher among patients treated with TAE than among those treated without TAE [122 (93.9%) vs. 112 (86.2%); odds ratio = 2.45; 95% CI 1.02-5.86; p = 0.039]. CONCLUSIONS: TAE use was associated with improved survival at 28 days in patients with pelvic fracture and should therefore be considered in the management of severely injured patients with pelvic fracture.

Effects of Teriparatide on Treatment Outcomes in Osteoporotic Hip and Pelvic Bone Fractures: Meta-analysis and Systematic Review of Randomized Controlled Trials.

The primary objective of this study was to evaluate randomized controlled trials (RCTs) that have reported the effects of teriparatide on bone-healing in osteoporotic hip and pelvic bone fractures to determine the efficacy of teriparatide in lowering the rate of treatment failure. A total of 2,809 studies were identified using a comprehensive literature search (MEDLINE [n=1,061], Embase [n=1,395], and Cochrane Library n=353]). Five RCTs were included in the final analysis. Treatment failure rates at the last follow-up of osteoporotic hip and pelvic bone fractures between the teriparatide and control groups was the primary outcome. Treatment failure was defined as non-union, varus collapse of the proximal fragment, perforation of the lag screw, and any revision in cases due to mechanical failure of the implant during the follow-up period. The number of treatment failures in the teriparatide and placebo groups were 11.0% (n=20 out of 181) and 17.6% (n=36 out of 205), respectively. Although the rate of treatment failure in the teriparatide group was lower than that in the control group, this difference was not significant (odds ratio, 0.81 [95% confidence interval, 0.42-1.53]; P=0.16; I2=42%). This meta-analysis did not identify any significant differences in the rate of treatment failure between the teriparatide and control groups at final follow-up. Based on these results, we believe that there is a lack of evidence to confirm efficacy of teriparatide in reducing treatment failures in osteoporotic hip and pelvic bone fractures.

Nanoscale light element identification using machine learning aided STEM-EDS.

Light element identification is necessary in materials research to obtain detailed insight into various material properties. However, reported techniques, such as scanning transmission electron microscopy (STEM)-energy dispersive X-ray spectroscopy (EDS) have inadequate detection limits, which impairs identification. In this study, we achieved light element identification with nanoscale spatial resolution in a multi-component metal alloy through unsupervised machine learning algorithms of singular value decomposition (SVD) and independent component analysis (ICA). Improvement of the signal-to-noise ratio (SNR) in the STEM-EDS spectrum images was achieved by combining SVD and ICA, leading to the identification of a nanoscale N-depleted region that was not observed in as-measured STEM-EDS. Additionally, the formation of the nanoscale N-depleted region was validated using STEM-electron energy loss spectroscopy and multicomponent diffusional transformation simulation. The enhancement of SNR in STEM-EDS spectrum images by machine learning algorithms can provide an efficient, economical chemical analysis method to identify light elements at the nanoscale.

A new class of lightweight, stainless steels with ultra-high strength and large ductility.

Steel is the global backbone material of industrialized societies, with more than 1.8 billion tons produced per year. However, steel-containing structures decay due to corrosion, destroying annually 3.4% (2.5 trillion US$) of the global gross domestic product. Besides this huge loss in value, a solution to the corrosion problem at minimum environmental impact would also leverage enhanced product longevity, providing an immense contribution to sustainability. Here, we report a leap forward toward this aim through the development of a new family of low-density stainless steels with ultra-high strength (> 1 GPa) and high ductility (> 35%). The alloys are based on the Fe-(20-30)Mn-(11.5-12.0)Al-1.5C-5Cr (wt%) system and are strengthened by dispersions of nano-sized Fe3AlC-type κ-carbide. The alloying with Cr enhances the ductility without sacrificing strength, by suppressing the precipitation of κ-carbide and thus stabilizing the austenite matrix. The formation of a protective Al-rich oxide film on the surface lends the alloys outstanding resistance to pitting corrosion similar to ferritic stainless steels. The new alloy class has thus the potential to replace commercial stainless steels as it has much higher strength at similar formability, 17% lower mass density and lower environmental impact, qualifying it for demanding lightweight, corrosion resistant, high-strength structural parts.