Risk Of Femoral Fracture Research Articles

Perioperative Fracture Risk and Two-Year Survivorship of a Short Tapered Femoral Stem following Direct Anterior Approach Cementless Total Hip Arthroplasty with a Fracture Table

AbstractThe cementless, tapered wedge, short femoral stem implant is commonly used in direct anterior approach (DAA) total hip arthroplasty (THA). The lack of access and visualization, however, may increase the risk of perioperative fracture and early failure. Therefore, the current study examined perioperative complications and 2-year implant survivorship following DAA THA performed using a fracture table and short, tapered wedge femoral stem. A retrospective analysis was conducted on patients having undergone DAA THA with a cementless, tapered wedge, short femoral stem. Perioperative fractures were noted and survivorship was determined by the incidence of revision surgery within a minimum 2-year follow-up period. A total 366 consecutive patients (441 hips) were identified in the cohort. Four patients (6 hips; 1.4%) were lost to follow-up and three patients died from unrelated causes. Average follow-up time for the remaining 359 patients (435 hips) was 32.9 ± 10.2 months. There were no intraoperative factures but three perioperative fractures within two weeks. Aseptic loosening occurred in one stem at 13 months, resulting in a 99.1% survival rate with a mean survival time of 23.8 ± 0.1 months (95% confidence interval: 23.6–24.0 months). The use of a short, tapered wedge femoral stem and a fracture table for DAA THA resulted in 0.7% periprosthetic fractures and only one aseptic loosening within 2 years. These results suggest that proper femoral exposure with the use of a fracture table and a short, tapered wedge femoral stem does not appear to increase the risk of periprosthetic femoral fracture.

Preterm birth and the future risk of orthopedic fracture.

Preterm birth occurs during a critical period of bone mineralization. We assessed whether preterm birth increases the risk of childhood fracture. We analyzed a cohort of 788,903 infants born between 2006 and 2016 in Quebec, Canada. The exposure was preterm birth (<37 weeks). The outcome was any future hospitalization for fracture before 2018. We estimated hazard ratios (HR) and 95% confidence intervals (CI) for the association of prematurity with fractures in adjusted Cox regression models. We determined if the risk of facture varied by the child's age. The incidence of fracture hospitalizations was higher in preterm children than in term children (17.9 vs. 15.3 per 10,000 person-years). Compared with term, preterm children had 1.27 times the risk of femur fracture hospitalization (95% CI 1.01-1.60) and 2.27 times the risk of assault-related fractures (95% CI 1.37-3.76). Preterm children had 2.20 times the risk of femur fracture between 6 and 17 months of age (95% CI 1.45-3.35). Preterm birth is associated with an increased risk of hospitalization for femur fractures and assault-related fractures. Associations are stronger before 18 months of age. Families of preterm children may benefit from counseling and support for fracture prevention during early childhood.

Iliaca Fascia Blocks for Pre-op Pain Management in Hip Fractures

Hip and proximal femur fractures are becoming increasingly common, especially as our population ages. Patients who have suffered a hip or proximal femur fracture can expect to experience pain. Each patient's level of pain is unique but has historically been managed with opioids. There has been much attention paid lately to the opioid crisis and the need to reduce consumption. Most patients at risk for hip and proximal femur fracture are the elderly. With this population, the need to prevent delirium is imperative. Delirium in this population will increase the length of stay and add to increased morbidity and mortality. The purpose of this review article is to show the benefits of using iliaca fascia blocks at first presentation and also that the iliaca fascia block can be performed by any number of stakeholders involved in the care of hip fracture patients.

Diabetes and fractures: new evidence of atypical femoral fractures?

Patients with diabetes have an increased risk of femoral fractures, but little is known about the risk of atypical femoral fractures (AFFs). The aim of this study was to identify the risk of subtrochanteric and femoral shaft (ST/FS) fractures and estimate the risk of AFFs in patients with type 1 (T1D) and type 2 diabetes (T2D). From the nationwide Danish National Patient Register, we identified patients with T1D (n = 19,896), T2D (n = 312,188), and sex- and aged-matched controls without diabetes (n = 996,252) from the general population and all ST/FS fractures (n = 7509). Data were analyzed using a Cox proportional-hazards model and the incidence rate and rate ratio of ST/FS fractures were estimated. The incidence rate of ST/FS fractures in T1D was 52.14 events per 100,000 person years and 73.21 per 100,000 person years in T2D. T1D was associated with an increased risk of ST/FS (HR 2.07 (95% CI 1.68-2.56)), whereas T2D was not (HR 0.99 (95% CI 0.94-1.10)). Previous ST/FS fractures were associated with an increased risk of subsequent ST/FS fractures (HR 6.95 (95% CI 6.00-8.05)) and the use of bisphosphonates with an increased risk of ST/FS fractures (HR 1.72 (95% CI 1.54-1.91)). Patients with T1D have a higher risk of ST/FS fractures compared with sex- and age-matched controls. Since a proportion of ST/FS fractures are classified as AFFs, this could point towards the fact that AFFs also are increased in patients with T1D, but not T2D.

Comparing the fracture limits of the proximal femur under impact and quasi-static conditions in simulation of a sideways fall

Sideways falls onto the hip are responsible for a great number of fractures in older adults. One of the possible ways to prevent these fractures is through early identification of people at greatest risk so that preventive measures can be properly implemented. Many numerical techniques that are designed to predict the femur fracture risk are validated through performing quasi-static (QS) mechanical tests on isolated cadaveric femurs, whereas the real hip fracture is a result of an impact (IM) incident. The goal of this study was to compare the fracture limits of the proximal femur under IM and QS conditions in the simulation of a sideways fall to identify any possible relationship between them.Eight pairs of fresh frozen cadaveric femurs were divided into two groups of QS and IM (left and right randomized). All femurs were scanned with a Hologic DXA scanner and then cut and potted in a cylindrical tube. To measure the stiffness in two conditions of the single-leg stance (SLS) and sideways fall (SWF), non-destructive tests at a QS displacement rate were performed on the two groups. For the destructive tests, the QS group was tested in SWF configuration with the rate of 0.017 mm/s using a material testing machine, and the IM group was tested in the same configuration inside a pneumatic IM device with the projectile target displacement rate of 3 m/s.One of the IM specimens was excluded due to multiple strikes. The result of this study showed that there were no significant differences in the SLS and SWF stiffnesses between the two groups (P = 0.15 and P = 0.64, respectively). The destructive test results indicated that there was a significant difference in the fracture loads of the two groups (P < 0.00001) with the impact ones being higher; however, they were moderately correlated (R2 = 0.45). Also, the comparison of the fracture location showed a qualitatively good agreement between the two groups.Using the relationship developed herein, results from another study were extrapolated with errors of less than 12%, showing that meaningful predictions for the impact scenario can be made based on the quasi-static tests. The result of this study suggests that there is a potential to replace IM tests with QS displacement rate tests, and this will provide important information that can be used for future studies evaluating clinical factors related to fracture risk.

Outcomes of Cement in Cement Revision, in Revision Total Hip Arthroplasty.

BACKGROUND:The cement-in-cement femoral revision technique involves removing a femoral component from a well-fixed femoral cement mantle and cementing a new stem into the original mantle. This technique, when carried out for the correct indications, is fast, relatively inexpensive and carries a reduced short-term risk for the patient compared with conventional way of removing well-fixed cement.AIM:To analyze the effectiveness of cement in cement revision of the femoral stem while performing a revision Total Hip Arthroplasty (THA).METHODS:We analyzed a consecutive series of 79 patients who underwent a cement in cement revision THA between June-2015 to June-2018. All the patients were retrospectively analysed for operative time, complications, clinical and radiological outcomes.RESULTS:Average age was 76 years (49-86). The mean follow-up was 16.2 months (12-45). The average operative time was 184.6 (90-290) minutes. Most common indication was cup loosening in 28 patients (42.4%), dislocation in 14 patients (21.2%) and stem loosening in 12 patients (18.2%) Nine patients (11%) had one or more complications. Pre-operatively, 10 patients (13%) had lucency at the cement bone interface. Recent review has shown that 8 of these patients’ radiographs have remained unchanged, and in 2 of them there is a slight progression of lucency. Common post op clinical complaintswere persistent pain and abductor weakness. Five (6.3%) patients required a re-revision. Most of the patients had a good or satisfactory outcome.No stems showed radiological loosening.CONCLUSION:The cement-in-cement technique for revision of the femoral component gave promising results and had the advantages of speed, less blood or bone stock loss, less risk of femoral perforation or fracture, decreased financial costs and reduced post op morbidity.

Axial cortical involvement of metastatic lesions to identify impending femoral fractures; a clinical validation study

Background and purposePatients with advanced cancer may develop painful bone metastases, potentially resulting in pathological fractures. Adequate fracture risk assessment is of key importance to prevent fracturing and maintain mobility. This study aims to validate the clinical reliability of axial cortical involvement with a 30 mm threshold on conventional radiographs to assess fracture risk in femoral bone metastases. Materials and methodsAll patients with bone metastases who received radiotherapy for pain included in two multicentre prospective studies were selected. Conventional radiographs obtained at a maximum of two months prior to radiotherapy were collected. Three experts independently measured lesions and scored radiographic characteristics. Sensitivity, specificity, positive (PPV) and negative predictive value (NPV) were calculated. ResultsHundred patients were included with a median follow-up of 23.0 months (95%CI: 10.6–35.5). Two fractures occurred in lesions with axial cortical involvement <30 mm, and 12 in lesions ≥30 mm. Sensitivity, specificity, PPV and NPV of axial cortical involvement for predicting femoral fractures were 86%, 50%, 20% and 96%, respectively. Patients with lesions ≥30 mm had a 5.3 times higher fracture risk than patients with smaller lesions. ConclusionOur validation study confirmed the use of 30 mm axial cortical involvement to assess fracture risk in femoral bone metastases. Until a more accurate and practically feasible method has been developed, this clinical parameter remains an easy method to assess femoral fracture risk to aid patients and clinicians to choose the optimal individual treatment modality.

Age-related periosteal expansion at femoral neck among elderly women may maintain bending stiffness, but not femoral strength.

Periosteal expansion and bone loss are two accompanying biological phenomena in old population. Their combined effect on bone stiffness, strength, and fracture risk is still not clear, because previous studies have reported contradictory results. A recently developed DXA (dual-energy X-ray absorptiometry)-based beam model was applied to study the effect at the femoral neck. We first made a theoretical analysis. Then, a clinical cohort consisting of 961 women (316 hip fractures and 645 controls, age of 75.9 ± 7.1) was used to investigate the associations quantitatively. We investigated (1) correlations of femoral-neck width and bone mineral density with femoral stiffness and strength; (2) correlations of femoral stiffness, strength, and hip fracture risk index with age; (3) associations of femoral stiffness, strength and fracture risk index with actual fracture status, measured by the area under the curve (AUC) and odds ratio (OR). The investigation results showed that (i) femoral-neck width had stronger correlation with femoral bending stiffness (r = 0.61-0.82, p < 0.001) than with the other stiffness components, while bone mineral density had stronger correlation with axial/shearing stiffness (r = 0.84-0.97, p < 0.001), strength (r = 0.85-0.92, p < 0.001), and fracture risk index (r = -0.61-0.62, p < 0.001) than with bending stiffness. (ii) The association between femoral bending stiffness and age was insignificant (r = - 0.06-0.05, r > 0.05); The associations of axial/shearing stiffness (r = - 0.27--0.20, p < 0.001), strength (r = - 0.28, p < 0.001), and fracture risk index (r = 0.38, p < 0.001) with age were significant. (iii) Fracture risk index had the strongest association with actual fracture status (AUC = 0.75, OR = 3.19), followed by strength (AUC = 0.74, OR = 2.84) and axial/shearing stiffness (AUC = 0.56-0.65, OR = 2.39-2.49). Femoral bending stiffness had the weakest association (AUC = 0.48-0.69, OR = 1.42-2.09). We concluded that periosteal expansion may be adequate to maintain femoral bending stiffness among elderly women, but it may not help preserve strength and reduce hip fracture risk.

CORR Insights®: Does Screw Location Affect the Risk of Subtrochanteric Femur Fracture After Femoral Neck Fixation? A Biomechanical Study.

CORR Insights®: Does Screw Location Affect the Risk of Subtrochanteric Femur Fracture After Femoral Neck Fixation? A Biomechanical Study.

Femoral Intertrochanteric Fractures of the Patients in the Emergency Department due to Minor Falls: Special Consideration in the Middle-old to Oldest-old Patients.

BackgroundThe older population (≥65 years) has rapidly increased in size in recent years. Among them, the middle-to-oldest-old (≥75 years) tend to have a poor health status. Therefore, subdivision and evaluation of older patients with traumatic injury are required. We focused on the risk of femoral intertrochanteric fractures occurring in older adults due to minor falls and compared young-old and middle-to-oldest-old populations.MethodsThe medical records of patients who visited the emergency center due to hip injuries between March 2017 and March 2019 were retrospectively analyzed. Patients were divided into older adult (≥65 years) and non-older (age 18–64 years) groups; the older adult group was subdivided into young-old (65–74 years), middle-old (75–84 years), and oldest-old (≥85 years) groups. This study investigated the occurrence rate of femoral intertrochanteric fractures and related factors.ResultsThe older adult group had a higher incidence of femoral intertrochanteric fractures than that in the non-older adult group (95.3% vs. 4.7%, p<0.001). However, there was no significant difference between young-old and non-older groups (58.8% vs. 41.2%, p=0.145). Middle-old to oldest-old age and osteoporosis were associated with an increased incidence of femoral intertrochanteric fractures (p<0.001, p=0.004). ConclusionA higher incidence of femoral intertrochanteric fractures from minor falls was found among middle-old to oldest-old patients compared to that in young-old patients. Therefore, physicians should perform more thorough physical examinations and radiograph reading in middle-old to oldest-old patients even if the patients do not complain of pain.

The impact of polyethylene abrasion on the occurrence of periprosthetic proximal femoral fractures in patients with total hip arthroplasty.

In addition to abrasion-induced osteolysis and ensuing instabilities, the polyethylene (PE) abrasion of total hip arthroplasty (THA) inlays can also cause gait instability due to the decentralization of the hip joint. The current literature yields, as yet, insufficient findings whether these two factors are linked directly or indirectly to a higher risk for periprosthetic proximal femoral fractures (PPFF). The aim of our retrospective evaluation is to analyse the impact of PE abrasion on the pathology of PPFF in patients with THA. The retrospective evaluation comprises all PPFF in patients with THA in the period from 01/2010 up to 12/2016. The study group (SG) included 66 cases (n = 66). The control group (CG) was comprised of patients with asymptomatic THA (n = 66), who were treated by our outpatient department including routine check-ups and X-ray examinations. We used the matched-pair methodology to scale the period of postsurgical care of the CG to the lifetime of the implant up to PPFF in the SG. We included epidemiologic data, radiological femoral head decentralization, osteolysis (Gruen classification), instabilities, acetabular cup position, and implant properties in our analysis. For the SG, we also included intra-operative signs of abrasion. The SG showed significantly higher numbers of decentralized THA as signs of inlay erosion with 73% compared to only 41% in the CG (p > 0.001). The SG showed 1 ± 0.68mm hip joint decentralization as to 0.5 ± 0.59mm in the CG (p = 0.004). We found significantly more cases of osteolysis in the SG (n = 25) than in the CG (n = 13) (p = 0.003). We found no notable differences in acetabular cup inclination or anteversion as well as cup size. However, differences were significant in femoral head size (SG 32 ± 2.3mm, CG 36 ± 2.4mm; p = 0.042) and head material. We found more widespread use of metal femoral heads in the SG than in the CG (SG 1:1, CG 1:21; p = 0.001). PPFF patients showed significantly higher rates of inlay erosion, resulting in femoral head decentralization and osteolysis. The higher rate of fracture is likely caused by the increasing instability of the implant fixation due to abrasion-induced osteolysis and the associated degradation of bone quality. It is conceivable that the abrasion and decentralization of the THA can also lead to gait instability, and thus, a higher proneness to falls. Gait instability can also be aggravated by increased granulation tissue and effusion due to the inlay abrasion. Although this cannot be substantiated by the investigation. In patients with decentralization of the THA and osteolysis, a radiological follow-up should be performed, and in case of gait instability (femoral head and) inlay replacements should be considered.

Does Screw Location Affect the Risk of Subtrochanteric Femur Fracture After Femoral Neck Fixation? A Biomechanical Study.

Case reports suggest that there is an increased risk of subtrochanteric femur fracture after femoral neck fixation with cannulated screws when the distal-most screw is placed distal to the lesser trochanter. However, to our knowledge, there are no biomechanical data supporting this observation. (1) Is there an increased risk of subtrochanteric femur fracture after femoral neck fixation with cannulated screws in normal density and osteoporotic Sawbones when the distal-most screw is started distal to the lesser trochanter? (2) Does the screw starting point position after femoral neck fixation with cannulated screws affect load to failure when normal density and osteoporotic Sawbones are loaded through their mechanical axis? Normal density and osteoporotic Sawbones femora were instrumented with three cannulated screws in a triangular apex distal configuration with the distal-most screw starting either proximal to, at, or distal to the level of the lesser trochanter. Specimens were loaded along the mechanical axis to failure. The fracture location and ultimate load to failure were compared between groups. The screw start point distal to the lesser trochanter resulted in a greater proportion of subtrochanteric femur fractures compared with screw start points at or proximal to the lesser trochanter in the subset of osteoporotic specimens (three of 10 specimens versus 0 of 20 specimens; p = 0.030). No subtrochanteric femur fractures were observed in the normal density specimens. Load to failure was lower when the distal-most screw was started distal to the lesser trochanter than when it was started at or proximal to the lesser trochanter (normal density subset 13,502 ± 1980 N versus 14,675 ±1528 N; osteoporotic subset 8946 ± 1509 N versus 10,026 ± 1256 N; linear regression coefficient 1127 N [95% CI 298 to 1956 N]; adjusted r = 0.71; p = 0.009). A screw start point distal to the lesser trochanter was associated with subtrochanteric femur fractures in the osteoporotic subset. Additionally, there was decreased load to failure when the distal-most screw was started distal to the lesser trochanter. These data suggest that avoiding a screw start point distal to the level of the lesser trochanter in femoral neck fracture fixation may decrease the risk of catastrophic subtrochanteric femur fractures, especially in patients with osteoporosis. However, it should be noted that a more overall varus screw alignment could theoretically compromise the ability to achieve compression across the fracture, with attendant implications with regard to fracture union in the acute setting.

High bisphosphonate treatment rates and the prevalence of atypical femoral fractures in patients with systematic lupus erythematosus: a single-center retrospective study performed in Japan

Treatment of systemic lupus erythematosus (SLE) often continues with moderate-to-low doses of glucocorticoids for the long term. Bisphosphonates aid in the prevention and management of glucocorticoid-induced osteoporosis (GIOP). However, long-term use of bisphosphonates increases the relative risk of atypical femoral fracture (AFF) and the incidence is typically 16 or 113 per 100,000 person-years in patients treated with bisphosphonates for 5 or 10years, respectively. Here, we explored bisphosphonate prescription rate and prevalence of AFF in patients with SLE. In total, 270 patients with SLE were enrolled. The Japanese Society for Bone and Mineral Research Guideline 2014 for GIOP management and treatment was used. We also explored AFF history through medical records. Most (n = 251) patients were recommended to treat by the GIOP guideline (scores ≥ 3); bisphosphonates, denosumab, teriparatide, or active vitamin D was prescribed for 85.7%. Bisphosphonates were currently used by 66.1% of the patients, and 65% had used them for ≥ 5years. Of all patients, 76.7% had a history of bisphosphonate use, 5 of 270 (1.9%) had histories of AFF. Four of five patients with AFF had taken bisphosphonates for ≥ 3.5years, in addition to moderate doses (≥ 10mg/day) of glucocorticoids. For the SLE patients with a history of bisphosphonate use, the incidence of AFF was calculated to be 278 per 100,000 person-years. Our single-center study found that bisphosphonates were commonly used long term by Japanese patients with SLE. As AFF is not rare, AFF should be cared in patients with SLE.

Thyrotoxicosis Involves β2-Adrenoceptor Signaling to Negatively Affect Microarchitecture and Biomechanical Properties of the Femur.

Background: Thyrotoxicosis increases bone turnover, resulting in net bone loss. Sympathetic nervous system (SNS) activation, via β2-adrenoceptor (β2-AR) signaling, also has osteopenic effects. Because thyroid hormones (TH) interact with the SNS to regulate several physiological processes, we hypothesized that this interaction also occurs to regulate bone mass. Previous studies support this hypothesis, as α2-AR knockout (KO) mice are less susceptible to thyrotoxicosis-induced osteopenia. Here, we evaluated whether TH-SNS interactions in bone involve β2-AR signaling. Methods: Thyrotoxicosis was induced in 120-day-old female and male mice with β2-AR gene inactivation (β2-AR-/-) by daily treatment with supraphysiological doses of triiodothyronine (T3) for 12 weeks. The impact of thyrotoxicosis on femoral bone microarchitecture, remodeling, fracture risk, and gene expression of the receptor activator of nuclear factor-kappa-B (RANK)-RANK ligand (RANKL)-osteoprotegerin (OPG) pathway was evaluated. In addition, the effect of the β2-AR-specific agonist clenbuterol (CL) on cAMP accumulation was determined in osteoblastic (MC3T3-E1) cells treated with T3 and/or 17β-estradiol (E2). Results: Thyrotoxicosis negatively affected trabecular bone microarchitecture in wild-type (WT) females, but this effect was milder or nonexistent in β2-AR-/- animals, whereas the opposite was seen in males. T3 treatment increased the femoral RANKL/OPG mRNA ratio and the endosteal perimeter and medullary area of the diaphysis in WT females and males, but not in β2-AR-/- mice, suggesting that T3 promotes endosteal resorption in cortical bone, in a mechanism that involves β2-AR signaling. T3 treatment increased endocortical mineral apposition rate only in WT females but not in β2-AR-/- mice, suggesting that TH also induce bone formation in a β2-AR signaling-dependent mechanism. T3 treatment decreased femoral resistance to fracture only in WT females, but not in KO mice. E2 and CL similarly increased cAMP accumulation in MC3T3-E1 cells; whereas T3 alone had no effect, but it completely blocked E2-stimulated cAMP accumulation, suggesting that some T3 effects on bone may involve E2/cAMP signaling in osteoblasts. Conclusions: These findings sustain the hypothesis that T3 interacts with the SNS to regulate bone morphophysiology in a β2-AR signaling-dependent mechanism. The data also reveal sex as an important modifier of skeletal manifestations of thyrotoxicosis, as well as a modifier of the TH-SNS interactions to control bone microarchitecture, remodeling, and resistance to fracture.

The relationship between obesity and fractures

There has been very limited analysis of the relationship between obesity and fractures in the orthopaedic literature. It has been established for some years that underweight individuals are at greater risk of proximal femoral fractures but recently there has been interest in the susceptibility of obese post-menopausal females to fracture. We have undertaken an analysis of 4886 adult patients who presented with a fracture and had their BMI assessed. Analysis has confirmed the relationship between underweight individuals and proximal femoral fractures but there is also a negative association between obesity and clavicle fractures in males and females and with calcaneal fractures in females. There is a positive relationship between obesity and proximal humeral, finger phalangeal and ankle fractures in males and with humeral diaphyseal, carpal and ankle fractures in females. There was no relationship found between open or multiple fractures and obesity.

Hypoglycaemia and type 1 diabetes are associated with an increased risk of fractures.

Studies have shown that type 1 diabetes (T1D) and type 2 diabetes (T2D) are associated with increased risk of fractures. Especially, subjects with T1D have an increased risk of fractures. The purpose of this study was to investigate the association of T1D, hypoglycaemia and insulin on fracture risk. A cohort study with T1D subjects (n = 19,896) and T2D subjects (n = 312,188) matched with subjects from the general populated (n = 996,252) and a nested case-control study with T1D subjects with fracture (n = 895) as cases and T1D subjects without (n = 2685) as controls were conducted based on subjects from the Danish National Patient Registry (DNPR). T1D (HR = 2.47, 95% CI 2.37 to 2.59), age (HR = 1.05, 95% CI 1.05 to 1.05), previous fracture (HR = 1.95, 95% CI 1.92 to 1.99) and being female (HR = 2.06, 95% CI 2.04 to 2.09) increased the risk of fractures. Also, T2D (HR = 1.14, 95% CI 1.11 to 1.18) increased the risk of proximal upper arm and shoulder fractures. T1D (HR = 2.41, 95% CI 2.20 to 2.65) increased the risk of hip and femoral region fractures. Hypoglycaemia (OR = 1.58, 95% CI 1.27 to 1.97) increased the risk of fractures, whereas insulin use did not change the risk. Hypoglycaemic episodes are associated with increased fracture risk, and the frequency of hypoglycaemic episodes leading to hospital admission was above 16% for T1D subjects. Prevention of hypoglycaemia is thus an important focus area in the prevention of fractures.

Incidence and pattern of periprosthetic hip fractures around the stem in different stem geometry.

The number of total hip arthroplasties (THA) is expected to increase worldwide; thus, complications are likely to increase at the same ratio. In this scenario, periprosthetic femoral fractures (PFFs) are an increasing concern. Identifying the predisposing factors is important in order to prevent as much as possible the risk of PFF in the future. The purpose of this study was to correlate the risk of periprosthetic femoral fractures to the most common patients' comorbidities and stem geometry. We reviewed all THA for non-oncologic indications between 2004 and 2014 with a mean follow-up of six years (range, 2-12). Three thousand two hundred forty-eight patients (3593 implants) were enrolled in the study, and 45 PFF were registered during this time period. Two thousand five hundred seventy-seven implants (71%) were straight stems, and 1015 (28.3%) were anatomic stems. All X-rays were then analyzed and classified according to the modified Vancouver classification. Periprosthetic femoral fractures incidence was associated with anatomic stem geometry (p < 0.001, OR = 2.2), BMI (p < 0.001), and diabetes (p < 0.001, OR = 5.18). PFFs were not significantly associated with age, gender, and all the other variables. Fracture pattern was different between straight and anatomic stems. Clamshell fractures were more likely to occur in anatomic stems compared to straight stems (p < 0.005). Periprosthetic femoral fractures are highly associated with obesity and osteoporosis. Anatomic stems reported a higher incidence of PPF than straight stems. The typical fracture type for anatomical stems is the clamshell pattern, while straight stems are more likely affected by type B fractures.

Modular Fluted Titanium Stems in Revision Hip Arthroplasty.

➤ Modular fluted titanium stems have become the implant of choice for most femoral component revisions as they have a lower risk of subsidence, thigh pain, femoral fracture, and stress shielding compared with previously used extensively coated cobalt-chromium stems.➤ Modularity of the femoral component allows for optimal and independent fit and fill of the proximal and distal femoral segments, permitting immediate axial and rotational stability in shorter diaphyseal segments (&lt;4 cm of scratch fit), thus reducing the risk of subsidence. Modularity also allows for independent adjustment of version of the proximal body relative to the distal stem, thus improving joint stability. The ability to make small adjustments in vertical and lateral offset further reduces the potential for instability and leg-length discrepancy, and the use of a titanium implant minimizes the risk of stress shielding compared with cobalt-chromium stems.➤ In several retrospective case series, excellent mid-term to long-term outcomes and low complication rates have been observed with the use of modular fluted titanium stems in femoral revisions.➤ The major disadvantages to the routine use of modular fluted titanium stems are the potential for taper junction failure (corrosion or fracture) and the increased cost of these stems compared with nonmodular stems.

Prediction of injury risks and features among scooter riders through MADYMO reconstruction of a scooter-microvan accident: Identifying the driver and passengers

In dealing with a scooter-related traffic accident with rider death, it is necessary to identify the driver responsible for the accident. This study aimed to reconstruct the kinematics of a scooter–microvan accident involving three riders and explored the differences in injury risks and characteristics of the scooter driver and passengers. We reconstructed a real accident by using MADYMO multi-body simulation software. Moreover, we designed two-variable simulation experiments to analyze how the velocity and impact angle of the microvan are related to the injuries of the three riders. When the microvan speed is set at 18 km/h and that of the scooter is set at 28.8 km/h, the simulated kinematics correlates well with real accident data, and the impact positions and injury parameters correlate well with the actual injuries. When the impact angle is smaller than 30° and the microvan impact velocity is lower than 40 km/h, the head injury of the driver is more life-threatening than the corresponding injuries of the rear passengers. When the impact angle is 15° and the microvan impact velocity is in the range of 0–20 km/h, the femur fracture risk is higher for the driver than for passengers. As the impact angle increases to 45°, passengers have a higher risk of femur fracture than the driver in the velocity range of 0–10 km/h. This impact velocity range becomes 0–30 km/h at an impact angle of 60° and then 40–70 km/h at an impact angle of 90°. Our study shows that the multibody method can reconstruct accidents and predict the different injury features and risks between the driver and passengers, which is useful in identifying the driver.

The design of the cemented stem influences the risk of Vancouver type B fractures, but not of type C: an analysis of 82,837 Lubinus SPII and Exeter Polished stems

Background and purpose — In total hip replacements, stem design may affect the occurrence of periprosthetic femoral fracture. We studied risk factors for fractures around and distal to the 2 most used cemented femoral stems in Sweden.Patients and methods — This is a register study including all standard primary Lubinus SPII and Exeter Polished stems operated in Sweden between 2001 and 2009. The outcome was any kind of reoperation due to fracture around (Vancouver type B) or distal to the stem (Vancouver type C), with use of age, sex, diagnosis at primary THR, and year of index operation as covariates in a Cox regression analysis. A separate analysis of the primary osteoarthritis patient group was done in order to evaluate eventual influence of the surgical approach (lateral versus posterior) on the risk for Vancouver type B fractures.Results — The Exeter stem had a 10-times (95% CI 7–13) higher risk for type B fractures, compared with the Lubinus, while no statistically significant difference was noticed for type C fractures. The elderly, and patients with hip fracture or idiopathic femoral head necrosis, had a higher risk for both fracture types. Inflammatory arthritis was a risk factor only for type C fractures. Type B fractures were more common in men, and type C in women. A lateral approach was associated with decreased risk for Type B fracture.Interpretation — Stem design influenced the risk for type B, but not for type C fracture. The influence of surgical approach on the risk for periprosthetic femoral fracture should be studied further.