Actual Fracture Research Articles

CT-derived indices of canine osteosarcoma-affected antebrachial strength.

To improve the prediction of fractures in dogs with bone tumors of the distal radius by identifying computed tomography (CT) indices that correlate with antebrachial bone strength and fracture location. Prospective experimental study. Dogs with antebrachial osteosarcoma (n = 10), and normal cadaver bones (n=9). Antebrachia were imaged with quantitative CT prior to biomechanical testing to failure. CT indices of structural properties were compared to yield force and maximum force using Pearson correlation tests. Straight beam failure (Fs), axial rigidity, curved beam failure (Fc), and craniocaudal bending moment of inertia (MOICrCd) CT indices most highly correlated (0.77 > R > 0.57) with yield and maximum forces when iOSA-affected and control bones were included in the analysis. Considering only OSA-affected bones, Fs, Fc, and axial rigidity correlated highly (0.85 > R > 0.80) with maximum force. In affected bones, the location of minimum axial rigidity and maximum MOICrCd correlated highly (R > 0.85) with the actual fracture location. CT-derived axial rigidity, Fs, and MOICrCd have strong linear relationships with yield and maximum force. These indices should be further evaluated prospectively in OSA-affected dogs that do, and do not, experience pathologic fracture.

A new estimation of equivalent matrix block sizes in fractured media with two-phase flow applications in dual porosity models

Single and multiphase flows in fractured porous media at the scale of natural reservoirs are often handled by resorting to homogenized models that avoid the heavy computations associated with a complete discretization of both fractures and matrix blocks. For example, the two overlapping continua (fractures and matrix) of a dual porosity system are coupled by way of fluid flux exchanges that deeply condition flow at the large scale. This characteristic is a key to realistic flow simulations, especially for multiphase flow as capillary forces and contrasts of fluid mobility compete in the extraction of a fluid from a capacitive matrix then conveyed through the fractures. The exchange rate between fractures and matrix is conditioned by the so-called mean matrix block size which can be viewed as the size of a single matrix block neighboring a single fracture within a mesh of a dual porosity model.We propose a new evaluation of this matrix block size based on the analysis of discrete fracture networks. The fundaments rely upon establishing at the scale of a fractured block the equivalence between the actual fracture network and a Warren and Root network only made of three regularly spaced fracture families parallel to the facets of the fractured block. The resulting matrix block sizes are then compared via geometrical considerations and two-phase flow simulations to the few other available methods. It is shown that the new method is stable in the sense it provides accurate sizes irrespective of the type of fracture network investigated. The method also results in two-phase flow simulations from dual porosity models very close to that from references calculated in finely discretized networks. Finally, calculations of matrix block sizes by this new technique reveal very rapid, which opens the way to cumbersome applications such as preconditioning a dual porosity approach applied to regional fractured reservoirs.

Technology Focus: Hydraulic Fracturing (March 2017)

Technology Focus Hydraulic fracturing is widely used all over the world, and in the Middle East in particular. Although superhigh-quality reservoirs do not need stimulation, the current expansion of reserves is mostly in newly found tight and unconventional resources that require extensive multi-stage fracturing for commercial production. Saudi Aramco embarked on stimulation and fracturing of wells at the beginning of its nonassociated conventional gas development endeavor and has been expanding and improving continuously in the areas of fracture design, use of novel materials, and field implementation. With newly discovered fields and the extension of existing areas, the challenges related to reservoir heterogeneity, tight rock, layered systems, and field maturity have led to innovative ideas and to testing and application of technologies. The use of biodegradable novel diversion systems (NDSs) has allowed fracturing multiple intervals in a single-stage operation, thereby reducing time and significantly cutting operational cost. On the basis of petrophysics and reservoir and geomechanical characteristics, multiple mesh sizes of an NDS are carefully designed and used to divert fluids in the wellbore, ensure simultaneous treatment of lower-quality intervals, and control excessive leakoff inside the fracture, creating longer and planar fractures for improved production. Diagnostics using production logging, temperature logs, and injecting and measuring nonradioactive tracers have shown expected production contribution and increase from target intervals, in both acid- and proppant-fracturing treatments. The superiority of NDSs lies in their natural formulation, simultaneous use in near-well and far-field applications, robustness in creating barriers and diversions, and easily degradable nature and flowback. Among other technology being developed and adopted in Saudi Arabia is the use of seawater-based fracturing fluids that will save the more-valuable fresh water. The laboratory experiments and the few field applications to date have shown stability at high temperatures and pressures, compatibility with formation fluids and fracturing additives, and resilience against scale formation. The use of seawater will serve the environment tremendously and will provide substantial economic benefits in remote areas where access to fresh water is challenging and costly. Saudi Aramco also has initiated the use of local sand as proppants combined with the channel fracturing technique, where proppants serve as pillars supporting and maintaining the induced fractures, keeping them open while the actual fracture conductivity is provided by the open areas within the system. The crushing of pillars by high in-situ stress and the friable quality of sand and consequent release of fines are controlled and contained by the use of resin during the treatment. This technology is also designed to reduce fracturing cost by eliminating more-expensive intermediate-strength proppant (ISP) or high-strength proppant (HSP) during channel fracturing. Sand cannot substitute for ISP or HSP in conventional fracturing because of its low compressive strength and friable nature. The economic advantage achieved by the use of new technologies will help expansion, exploration, drilling, and fracturing in new frontiers and territories. The world’s increasing energy demand, which, for the most part, is hydrocarbon dependent, requires growth and advancement in the oil and gas industry, increasingly environmentally friendly practices, the use of more natural resources, and the application of innovative ideas and new technology that will reduce development and management cost and increase efficiency and effectiveness. Recommended additional reading at OnePetro: www.onepetro.org. SPE 180207 Effects of Hydraulic Fractures on the Treatment of Condensate by Huff ’n’ Puff Gas Injection in Eagle Ford Shale by S. Yang, University of Calgary, et al. SPE 181353 Best Practices and Lessons Learned From More Than 1,000 Treatments: Revival of Mature Fields by Hydraulic Fracturing in Khalda Ridge, Egypt’s Western Desert by Mohamed Salah, Khalda Petroleum Company, et al. SPE 184840 Innovative Diversion Technology Ensures Uniform Stimulation Treatments and Enhances Gas Production: Examples From Carbonate and Sandstone Reservoirs by Zillur Rahim, Saudi Aramco, et al.

Reduced Fracture Finite Element Model Analysis of an Efficient Two-Scale Hybrid Embedded Fracture Model

A Hybrid Embedded Fracture (HEF) model was developed to reduce various computational costs while maintaining physical accuracy (Amir and Sun, 2016). HEF splits the computations into fine scale and coarse scale. Fine scale solves analytically for the matrix-fracture flux exchange parameter. Coarse scale solves for the properties of the entire system. In literature, fractures were assumed to be either vertical or horizontal for simplification (Warren and Root, 1963). Matrix-fracture flux exchange parameter was given few equations built on that assumption (Kazemi, 1968; Lemonnier and Bourbiaux, 2010). However, such simplified cases do not apply directly for actual random fracture shapes, directions, orientations …etc. This paper shows that the HEF fine scale analytic solution (Amir and Sun, 2016) generates the flux exchange parameter found in literature for vertical and horizontal fracture cases. For other fracture cases, the flux exchange parameter changes according to the angle, slop, direction, … etc. This conclusion rises from the analysis of both: the Discrete Fracture Network (DFN) and the HEF schemes. The behavior of both schemes is analyzed with exactly similar fracture conditions and the results are shown and discussed. Then, a generalization is illustrated for any slightly compressible single-phase fluid within fractured porous media and its results are discussed.

Keynote: Fatigue Hydraulic Fracturing

In this article, the concept of Fatigue Hydraulic Fracturing (FHF) is described, and its geothermal application is discussed. The basic idea behind fatigue fracturing is to vary the effective stress magnitudes at the fracture tip to optimize fracture initiation and growth. The optimization process can include lowering seismic radiated energy and/or generating fracture networks with various geometry and permeability. Historically, we start referring to results from mechanical laboratory core testing, discrete element simulation of fluid-induced seismicity, and application of cyclic water-fracs at the enhanced geothermal system site Groß-Schönebeck, Germany. Then, an in situ experiment at Äspö Hard Rock Laboratory is summarized to bridge the gap between laboratory core testing and wellbore-size hydraulic fracture treatments in hard rock. Three different fluid injection schemes (continuous, progressive and pulse injection) are tested underground in naturally fractured, crystalline rock mass in terms of associated induced seismicity and permeability performance. Under controlled conditions, hydraulic fractures are extended to about 20–40 m2 in size from a 28 m long, horizontal borehole drilled from a tunnel at 410 m depth. The facture process is mapped by an extensive array of acoustic emission and micro-seismic monitoring instruments. Results from three water-injection tests in Ävrö granodiorite indicate that the fracture breakdown pressure in tendency becomes lower and the number of fluid-induced seismic events becomes less when continuous, conventional fluid injection is replaced by progressive fluid-injection with several phases of depressurization simulating the fatigue treatment. One reason for this may be that in the dynamic, fatigue treatment a larger fracture process zone is generated compared to the size of the fluid pressurized zone developing during the injection phases into crystalline rock. We see mine-scale tests with hybrid sensor arrays of importance to identify and understand the actual hydraulic fracture mechanisms in hard rock. In addition, the mesoscale data obtained underground allow downscaling to laboratory core results, and upscaling to borehole reservoir stimulation results.

Creep life prediction of small punch creep testing specimens for service-exposed Cr5Mo using the theta-projection method

Abstract In this paper, small punch creep tests under different loads and conventional creep tests with various stresses at 550 °C were conducted on service-exposed Cr5Mo material. The theta-projection and modified theta-projection methods were used to analyze the creep curve and the minimum creep rate. The actual fracture time in the small punch creep test was 377 h, and the theta-projection method predicted a time of 339 h, which represents an error of 10.08%. The predicted time from the modified theta-projection method was 316.25 h, which represents an error of 16.11%. The curves predicted by the two models are similar. The theta-projection method is suitable for applications in small punch creep life analysis.

Trends in the Incidence of Clavicle Fractures and Surgical Repair in Sweden: 2001-2012.

Clavicle fractures are common injuries causing substantial morbidity. Recent literature suggests that the incidence of surgically treated clavicle fractures has increased. However, it is unknown whether the increase is caused by more surgeons choosing operative over nonoperative treatment for the injury or an increase in the actual incidence of clavicle fractures. The aim of this study was to assess both the national incidence of clavicle fractures and the rate of surgical treatment of those fractures in Sweden. We assessed the incidence and trends of clavicle fractures and rates of surgery in Sweden. The validated Swedish Hospital Discharge Register offers a unique opportunity to assess both outpatient and inpatient visits and was used to conduct a national register-based study including all adults (≥18 years of age) with a diagnosis of clavicle fracture in Sweden between 2001 and 2012. A total of 44,609 clavicle fractures occurred in Sweden between 2001 and 2012. The incidence of clavicle fractures increased from 35.6 per 100,000 person-years in 2001 to 59.3 per 100,000 person-years in 2012. Interestingly, the highest incidence rates were observed in the oldest age groups. The increase in the rate of surgically treated clavicle fractures (705%) was greater than the increase in the actual fracture incidence (67%). Most (77%) of the surgically treated patients were men. Open reduction and plate fixation was the most common surgical procedure. Overall, the proportion of surgically treated clavicle fractures increased markedly. Although the incidence of clavicle fractures increased in Sweden between 2001 and 2012, the rate of surgical treatment of clavicle fractures increased much more than could be expected solely based on the increase in the fracture incidence. The observed changes in the rates of surgery require additional studies since there is still controversy regarding the indications for surgical treatment.

Lightfix: A Prospective, Multi-Center Study of the Photodynamic Bone Stabilization System for the Treatment of Impending and Actual Pathological Fractures from Metastatic Bone Disease in the Humerus

Lightfix: A Prospective, Multi-Center Study of the Photodynamic Bone Stabilization System for the Treatment of Impending and Actual Pathological Fractures from Metastatic Bone Disease in the Humerus

A refined cohesive zone model that accounts for inertia of cohesive zone of a moving crack

Existing cohesive zone models assume that actual fracture zone of non-zero mass can be modeled by a line segment (cohesive zone) with no mass and inertia. In the present work, a simplified mass-spring model is presented to study inertia effect of cohesive zone on a mode-I steady-state moving crack. It is showed that fracture energy predicted by the present model increases dramatically when a finite limiting crack speed is approached. Reasonable agreement with known experiments indicates that the present model has the potential to catch the inertia effect of cohesive zone which has been ignored in existing cohesive zone models and better simulate dynamic fracture at high crack speed.

Evolution of traumatic spinal cord injury in patients with ankylosing spondylitis, in a Romanian rehabilitation clinic.

The ankylosing spondylitis (AS) is a systemic, multi-factorial, chronic rheumatic disease. Patients are highly susceptible to vertebral fractures with or without spinal cord injury (AS-SCI), even after a minor trauma. The study is a retrospective descriptive survey of post-acute, traumatic AS-SCI patients, transferred from the neurosurgical department and admitted in a Romanian Neurorehabilitation Clinic, during 2010-2014. There were 11 males associating AS-SCI (0.90% of all consecutive SCI admitted cases), with an average age of 54.6 years (median 56, limits 42-73 years). The average duration between the medically diagnosed AS and the actual associated spinal fracture(-s) moment was 21.4 years (median 23; limits 10-34 years). Low-energy trauma was incriminated in 54.5% cases. The spinal level of fracture was: cervical (four cases), thoracic (three), lumbar (four), assessed at admission as: American Spinal Injury Association (ASIA) Impairment Scale (AIS) A (four subjects), C (five) and D (two). By the time of discharge, neither patient has neurologically deteriorated; five patients (45.5%) improved of at least grade 1 (AIS). The overall complications were mainly infections: symptomatic urinary tract infections (seven patients; 63.6%), pulmonary (three subjects; 27.3%) and spondylodiscitis (one case; 9%). The average follow-up period was 15.3 months (median 12; limits 1-48 months) after discharge; three subjects gained functional improvement to AIS-E. The clinical profile (different risk factors, mechanisms, types and levels of spinal fractures, additional encephalic and/or cord lesions, co-morbidities), different post-surgical and/or general complications acquired during admission in our rehabilitation ward, served us for future prevention strategies and a better therapeutic management.

Three-dimensional fracture pattern analysis of the Obwegeser and Dal Pont bilateral sagittal split osteotomy

The Obwegeser and Dal Pont modification of the bilateral sagittal split osteotomy (BSSO) is a well-established procedure in orthognathic surgery. The purpose of this retrospective study was to analyze the actual fracture patterns achieved with BSSO by Obwegeser and Dal Pont modification using postoperative cone beam computed tomography (CBCT) datasets from 100 patients. A total of 200 split osteotomies were assessed, which could be categorized into nine different split patterns. Only one of the observed split fractures (0.5%) followed exactly the fracture line described by Obwegeser and Dal Pont, whereas 40% followed the fracture line according to the Hunsuck and Epker modification and 13.5% were seen as unfavourable splits mainly running over the buccal plate. A significant correlation was found between unfavourable buccal splits and both horizontal osteotomies reaching the buccal surface at the dorsal ramus (P=0.001) and a vertical caudal bone cut end at the corpus with a buccal position (P<0.001). These results show that a complete antero-posterior horizontal osteotomy at the mandibular ramus does not lead to the intended fracture pattern, which rebuts the argument of a greater amount of bony overlap using the Obwegeser and Dal Pont modification.

The Effect of Multi-inclined Holes on the Creep Properties of Nickel-Based Superalloy

AbstractThe creep properties of GH3536 nickel-based superalloy plate specimens without/with multi-inclined holes were studied under applied stress 80/90/100 MPa at 850 ℃, respectively. Interesting finding is focused on the inflection point, that is, both the fraction elongation and creep strain achieve the maximum value under 90 MPa. Further study is carried out by two methods: the finite element analysis (FEA) calculation and scanning electron microscope (SEM). The FEA results show that the dangerous areas appear in the regions near the end of ellipse axis along the inclined angle orientation, which is similar to the actual fracture appearances. What is more, the tiny holes and dimples are the main characters of creep fracture for multi-inclined hole specimens, whereas the creep fracture of specimens without holes is the result of growth and coalescence of voids. In addition, based on creep performance, laser drilling is better than that of the electric spark drilling, which provides a proof that the creep performance of specimens with multi-inclined holes will be better with the improvement of the drilling process.

Mechanical properties and their relations to microstructural characteristics of high-speed friction stir-welded AA6005A-T6 aluminum hollow extrusions

The AA6005A-T6 aluminum hollow extrusions were friction stir welded at high welding speeds ranging from 1200 to 3200 mm/min, and the mechanical properties and their relations to microstructural characteristics of joints were investigated in detail. Defect-free joints were obtained at the welding speeds less than 2400 mm/min, and voids appeared at the lower part of the nugget zone (NZ) in the joint welded at higher welding speed. The tensile tests revealed that increasing the welding speed decreased the tensile strengths of nonstandard joints monotonously, but it had little influence on the tensile strengths of standard joints. The evolutions of grains, dislocations, and strengthening precipitates in various zones led to the existence of the softened region, which consisted of NZ, thermo-mechanically affected zone (TMAZ), and heat-affected zone (HAZ). The increasing welding speed narrowed down the width of the softened region and enhanced the lowest microhardness value located in the HAZ. The fracture paths of nonstandard joints were all located in the HAZ on the retreating side (RS), while the standard joints fractured in the HAZ or HAZ/TMAZ interface on the RS or advancing side, which demonstrated that both the microstructures and structural characteristics influenced the actual fracture locations of nonstandard joints.

Estimation of hydraulic fracture volume utilizing partitioning chemical tracer in shale gas formation

Hydraulic fracture geometry is of the interest in optimizing stimulation treatment and forecasting production potential. Current diagnostic tools such as tiltmeter and microseismic are insufficient in evaluating fracture geometry. Knowing that gas from the shale reservoir has a much higher mobility than fracking fluid, partitioning chemical tracer is employed so that tracer data can be obtained earlier and more complete. The proposed approach is examined by synthetic numerical simulations. On the semi-log plot, tracer production declined tail clearly divides into two straight-line segments. Applying the moment of methods to the entire tracer production data gives the total volume of hydraulic fracture and the invaded matrix swept by the tracer due to leak-off. Additionally, extrapolating the first segment of tracer decline tail using the exponential law yields a volume that is close to the actual hydraulic fracture volume, especially when fracture permeability is several orders larger than matrix permeability.

The biomechanical cost of variable angle locking screws

IntroductionVariable angle (VA) locking plates in fracture fixation surgery allow screws to be fastened to the plate within a conical “locus of vectors” in order to avoid existing prostheses, joint surfaces, or poor quality bone. Clinical failures of VA constructs in which screws have rotated at the plate/screw interface have been reported raising the concern that there may be a biomechanical cost for the increased flexibility that VA provides. The objective of this study was to test the mechanical properties of one commonly used VA locking mechanism with screws placed in both nominal and off–axis trajectories and compare these against the standard locking mechanism. MethodsVA locking screws were inserted into plates for distal femur fractures (VA Curved Condylar) at various angles (0° to 15° away from perpendicular). A control group of standard locking screws/plates was also tested. Maximum moment at the screw/plate interface and moment at two reference displacements were determined. ResultsVA screws locked perpendicular to the plate provided the greatest maximum moment and moment at the reference displacements when using the VA system, and demonstrated lower moments compared to standard locking screws/plates (p<0.001). Based on linear regression, there was an average decrease of approximately 0.4 Nm screw-plate interface strength for every 1° increase in screw-plate angle (p<0.001). Decreases (p<0.05) were discovered in both maximum moment and moment at the reference displacements for screws locked at 5° relative to those locked at 0°, 10° relative to 0°, and 15° relative to 10°. DiscussionStandard locking systems provided greater resistance to rotational failure at the screw/plate interface than variable angle locking systems. Variable angle systems provided the greatest resistance to rotation when the screw was inserted perpendicular to the plate. As the off-axis angle increased, the resistance to rotation at the screw/plate interface decreased almost linearly. It is unknown if these differences are clinically significant in an actual fracture construct, but recent reported failures in the distal femur suggest that they might be. ConclusionSurgeons should weigh the risks and benefits of VA systems and attempt to minimize the off-axis angle magnitude when VA systems are selected.

Experimental evaluation of rolling contact fatigue in railroad wheels

Surface damage in railroad wheels is a very complex phenomenon and the contact fatigue plays a fundamental role in the damage process. In the case of railroad wheels the actual fracture process is quite different from the conventional idea of fracture in a load bearing structural component. The cracks that are generated by contact fatigue are not the source of actual wheels cracking but lead to the damaging phenomenon called shelling which implies separation of chunks of material from the surface. Shelling is mainly due to the presence of a fluid in the contact area, which penetrates in the fatigue cracks and causes a crack propagation leading to the separation of a portion of the wheel surface. A basic starting point to analyze this phenomenon is to study the crack development in the contact surface and to evaluate the behavior of different types of steels used for wheels manufacturing. However, the challenge to obtain a reliable similitude between laboratory and real conditions is far from straightforward.The present paper illustrates an experimental approach for rolling contact fatigue and shelling evaluation based on the possibility of simulating, in the laboratory, boundary conditions that can be scaled to the actual railroad, thus providing a realistic evaluation of the contact fatigue life of different steels.

Unidirectional Torsion Properties of Single Silk Fibre

The unidirectional torsion properties of silk fibre were investigated on a purpose-built single fibre torsion tester. The torsional fracture angle and the number of cycles of torsion at breaking were recorded, and the effect of the gauge length and pretension together with the torsion speed on the torsion properties of single silk fibre was investigated in detail. Scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis and a tensile tester were used to understand the morphology, structure and tensile properties of silk fibre after torsion deformation. SME photos show that silk fibre exhibits a ribbon-like profile after torsion, and fracture tends to occur at both ends of the silk fibre, where a larger number of twists can be observed. The crystallinity calculated from XRD spectra of silk fibre increases from 26.11% to 34.10% after torsion. The breaking stress and strain decreases slightly with an increase in the gauge length. The breaking cycle increases linearly with an increase in the gauge length, while the actual torsional fracture angle decreases gradually at the same time. The torsional fracture angle together with the breaking cycle decreases gradually as the pretension increases. The fracture angle together with the breaking cycle increases with an increase in the torsion speed. Understanding the unidirectional torsion properties of single silk fibre will benefit its further application in specific areas where the fibre will be subject to frequent torsion and deformation.

What Are the Functional Results and Complications With Long Stem Hemiarthroplasty in Patients With Metastases to the Proximal Femur?

Traditional treatments for pathological fractures of the proximal femur resulting from metastatic bone disease include fixation with intramedullary nailing supplemented with polymethylmethacrylate, osteosynthesis with a plate-screw construct and polymethylmethacrylate, or endoprosthetic reconstruction. Despite the frequent practice of these treatments, treatment outcomes have not been rigorously compared. In addition, very few studies examine specific approaches to endoprosthetic reconstruction such as long stem hemiarthroplasty. This study examines survival, functional outcomes, and complications associated with long stem hemiarthroplasty in a small group of patients treated for impending and actual pathologic fractures of the proximal femur resulting from metastatic bone disease. Between 2012 and 2015, 21 patients were treated with long stem cemented hemiarthroplasty in 22 limbs. During that time, indications for this approach included lesions from metastases, myeloma, or lymphoma involving the proximal femur that resulted in an impending or actual pathological fracture. An impending fracture was classified as a painful lesion with at least 50% cortical erosion. During the study period, six patients with proximal femoral metastases not deemed to meet these indications were treated with other surgical approaches such as intramedullary nailing supplemented with polymethylmethacrylate and osteosynthesis with a plate-screw construct and polymethylmethacrylate. Mortality was tracked through medical records and phone calls to the patients and their families. Followup for the entire group of patients (n=22) ranged from 1 to 27 months with a mean duration of 11 months. For patients with at least 1 year of followup (n=11), the mean duration was 18 months (range, 12-27 months) and for patients with less than 1 year of followup (n=11), the mean duration was 3 months (range, 1-11 months). Functional outcomes were evaluated according to the Musculoskeletal Tumor Society (MSTS) scoring system for lower extremities, the Eastern Cooperative Oncology Group (ECOG) Scale of Performance Status, and the Karnofsky Performance Scale (KPS) Index. Scores and complications were determined by direct patient examination, retrospective chart review, review of a longitudinally maintained institutional database, and followup phone calls. Ten patients died of disease within the followup period. Before surgery, the median total MSTS score for the entire group of patients (n=22) was 4.5 (range, 0-23), the median ECOG score was 3.5 (range, 1-4), and the median KPS score was 40 (range, 30-70). Postoperatively, the median total MSTS score (measured at most recent followup) for the entire group of patients was 21 (range, 5-30), the median ECOG score was 2 (range, 0-3, 68%≤2), and the median KPS score was 60 (range, 40-100). For the 11 patients with at least 1 year of followup, the median total MSTS score (measured at most recent followup) was 27 (range, 21-30), the median ECOG score was 1 (range, 0-2, 100%≤2), and the median KPS score was 80 (range, 60-100). For the remaining 11 patients with less than 1 year of followup, the median total MSTS score (measured at most recent followup) was 11 (range, 5-25), the median ECOG score was 3 (range, 1-3, 36% ≤ 2), and the median KPS score was 40 (range, 40-80). Complications included one periprosthetic fracture resulting from a fall, three cases of radiation-induced edema, and two cases of sciatica that developed unrelated to the procedure. Long stem cemented hemiarthroplasty results in fair levels of function in a complex population of patients whose prognosis is sometimes measured only in months and who otherwise might be disabled by their metastatic lesions. Comparative trials applying consistent indications and inclusion criteria should be performed between this approach and fixation with intramedullary nailing supplemented with polymethylmethacrylate as well as osteosynthesis with a plate-screw construct and polymethylmethacrylate. Level IV, therapeutic study.

What Is the Role of Allogeneic Cortical Strut Grafts in the Treatment of Fibrous Dysplasia of the Proximal Femur?

BackgroundManagement of fibrous dysplasia of the proximal femur is a progressive, often recurrent condition of bone that can cause skeletal deformity, fractures, and pain. Allogeneic cortical strut grafting to minimize the risk of fracture or as part of fracture treatment is a promising treatment option, but evidence is scarce on the intermediate- to long-term results of this procedure and there are no data on factors associated with graft failure.Questions/purposesThe purposes of this study were (1) to evaluate the revision-free survivorship; (2) radiographic findings; (3) factors associated with failure; and (4) complications associated with cortical strut allograft to prevent or treat fractures of the proximal femur in patients with fibrous dysplasia.MethodsBetween 1980 and 2013 we performed cortical strut allografting in 30 patients for impending or actual fractures of the proximal femur, of whom 28 (93%) were available for followup at a minimum of 2 years (mean, 13 years; range, 4–37 years) and of whom 22 (73%) had also been evaluated within the last 5 years. During that time, the indications for cortical strut allografting were an impending fracture of the proximal femur, persistent pain, or an actual nondisplaced femoral fracture. In patients who presented with a diaphyseal fracture, a fracture with severe dislocation of severe varus deformity, which required an osteotomy, placement of a blade plate was instead performed and these patients are not included here. During that time, for patients with diaphyseal fractures, and in patients with a displaced femoral fracture of the proximal femur, placement of a blade plate without strut grafting was instead performed; these patients are not included here. The primary outcome was the success rate of allogeneic cortical strut grafting surgery as assessed by the absence of revision surgery for a newly sustained fracture, resorption of the graft, or progressive deformity of the proximal femur. The association of possible contributing factors to graft failure such as gender, age at surgery, preoperative fracture, and anchoring distances of the graft in healthy bone was also evaluated using Cox regression analysis.ResultsRevision surgery was performed in 13 patients, resulting in a mean survival time of 13 years (Kaplan-Meier 95% confidence interval [CI], 10–16). Radiological resorption of the graft was observed in 15 of 28 patients (54%). However, revision surgery was not performed in all patients who developed graft resorption, because of the absence of a risk for fracture on the basis of the anatomical site of resorption. Identified risk factors for graft failure included preoperative fractures (hazard ratio [HR], 4.5; 95% CI, 1.2–17.2; p = 0.028) and insufficient proximal anchoring of the graft in healthy bone (HR, 6.02; 95% CI, 1.3–27; p = 0.02). One patient sustained a refracture after surgery resulting from an in-hospital fall. The fracture was treated without further surgery, and it healed.ConclusionsOur findings from this study suggest that cortical strut allografting may be a viable option for treatment of fibrous dysplasia of the proximal femur a without previous pathological fracture. Surgeons should pay particular attention to the proximal fixation point of the allograft to decrease the risk of failure. Patients with a fracture have an increased risk of failure and reoperation and so should be treated with an osteosynthesis.Level of EvidenceLevel IV, therapeutic study.

Updated Outcomes of Prophylactic Femoral Fixation.

Despite an increasing number of patients with metastatic bone disease (MBD), minimal data exist regarding outcomes of patients undergoing prophylactic femoral fixation for MBD when compared with other frequently performed orthopedic operations, such as hemiarthroplasty of the femur. The authors performed a retrospective database review evaluating these procedures due to similar operative times and patient populations and also reviewed common comorbidities such as body mass index (BMI). The goal was to provide updated results of prophylactic femoral fixation and evaluate whether certain patient risk factors (eg, BMI) altered 30-day survival for patients with MBD. The authors reviewed 1849 patients with and without MBD treated by prophylactic fixation and hemiarthroplasty from 2006 to 2011 identified in the American College of Surgeons National Surgical Quality Improvement Program database. There were no significant differences in complications between patients undergoing surgical treatment for impending or actual femoral fracture. In addition, there were no differences between the 217 patients with MBD in either the hemiarthroplasty or prophylactic fixation groups because the rate of death within 30 days postoperatively was 5.56% and 3.30%, respectively (P=.526). When comparing BMI, obese patients had higher rates of wound infection, and underweight patients were more likely to develop pneumonia or die within 30 days postoperatively. Patients with impending femur fractures benefit from prophylactic fixation and perform as well in the short term as patients undergoing hemiarthroplasty. Certain BMI categories (underweight or obese) contributed to poorer outcomes. These findings provide updated information for discussing risks and benefits with surgical candidates.