Metal Cup Research Articles

Long-term outcomes of acetabular impaction grafting with cemented cups and trabecular metal for revision hip arthroplasty: a follow-up study.

Revision hip arthroplasty in the presence of complex acetabular deficiencies is challenging. Cement, allograft, reconstruction rings and porous trabecular metal now provide versatile options for acetabular fixation and restoration of acetabular offset. We compare acetabular impaction bone grafting (AIBG) and trabecular metal (TM) cups at long-term follow-up. 53 patients who underwent revision hip arthroplasty were retrospectively reviewed from local joint registry data. 36 patients were revised using AIBG and 17 with TM. Median clinical follow-up was 9.57 (2.46-18.72) years and 9.65 (7.22-12.46) years, respectively. 82% of the TM group and 63% of the AIBG group were ⩾ Paprosky 2C. Re-revision was considered failure. Radiographs demonstrating 5 mm of femoral head migration and 5° of acetabular component inclination change were considered loose. Patients receiving AIBG were younger (68 vs. 74 years) with a longer interval from initial arthroplasty to revision (17 vs. 13 years). Revisions in both groups were indicated most commonly for failed cementing (AIBG 88.9% vs. TM 70.5%). No TM reconstructions underwent re-revision, with only 1 failing at 6.3 years, compared with 9 AIBG re-revisions. When revising for sepsis, 33% of AIBG revisions failed. AIBG demonstrated high failure rates at long-term follow-up when compared to TM constructs. We recommend the use of AIBG in small cavitary defects only. We strongly advise against its use in the setting of significant bony defects and for prosthetic joint infection.

Proof of Concept of a New Revision Procedure for Ceramic Inlays of Acetabular Cups Using a Shape-Memory Alloy Actuator System.

The revision of ceramic inlays of acetabular cups is a challenging surgical procedure. The mechanical impact during the inlay extraction process can damage the ceramic or metal cup rim. To avoid these risks, a concept for a new revision procedure was developed. It is based on an actuator system, which allows a non-destructive release of the ceramic inlay. To integrate the actuator system, different design concepts of acetabular cup components were investigated, and an actuator based on shape-memory alloy (SMA) wires was developed. The process chain for the actuator, starting from nickel-titanium wires manufactured into the actuator geometry by laser welding and thermo-mechanical treatment for the shape setting process up to the functionality evaluation of the actuator system, was implemented on a laboratory scale. The new revision procedure is based on a phase transformation of the SMA wire actuator, which was obtained through two methods-applying an electrical current by an instrument and rinsing the wire with heated water. The phase transformation of the actuator resulted in a contraction between 3.2% and 4.3% compared to its length after pre-stretching and was able to release the ceramic inlay from the cup. Therefore, the developed actuator design and process chain is a proof of concept towards a new revision procedure for modular acetabular cups.

Fusion Rates in Tibiotalocalcaneal Arthrodesis with Tantalum Coated Metal Cup Augmentation

Introduction/Purpose: Tantalum coated metal spacers (TCMS) have recently been utilized to fill and provide structure to large bony defects in the hindfoot. Tantalum is an appealing material due to its biocompatibility, lack of immune response generation, and structural integrity. Compared to custom printed spacers and bulk allografts, TCMS are readily available off-the-shelf implants with significantly less cost. There is currently a paucity of literature assessing the use and outcomes of TCMS in foot and ankle surgery, specifically in tibiotalocalcaneal (TTC) arthrodesis. This study serves to assess clinical outcomes and fusion rates of patients who underwent TTC arthrodesis utilizing intramedullary nailing with TCMS augmentation for large bony defects. Methods: We retrospectively identified all patients > 18 years of age who underwent TTC arthrodesis with TCMS augmentation at our tertiary care center between 2015-2021. We also identified all patients who underwent TTC arthrodesis without augmentation within that time frame. The computed tomography (CT) scans at the six-month postoperative point were reviewed by one board-certified orthopaedic foot and ankle surgeon to determine fusion status, which was defined as having at least 50% fusion mass. Patient-reported outcomes measures (PROMs) including the modified foot function index (FFI) and PROMIS Global Mental Health Score were collected for patients in both groups. Patient demographics, clinical outcomes, and PROMs were compared between groups. A multivariate logistic regression model measured the effect of TCMS augmentation on the likelihood of achieving fusion. Results: Of the 65 patients included, 21 patients (32.3%) underwent TTC with TCMS augmentation. There were no significant differences in demographics between the two groups. Patients in the TCMS group had significantly higher modified FFI (91.1 + 47.6 vs 26.3 + 48.8, p< 0.001) and PROMIS Global Mental Health (12.2 + 4.82 vs. 5.59 + 6.76, p< 0.001) scores in the postoperative period. Overall, the fusion rate was higher for the TCMS group, however the difference was not significant between groups (90.5% vs. 80.5%, p=0.472). Multivariate logistic regression identified that TCMS augmentation was a nonsignificant predictor of increased odds of fusion at the six-month postoperative point (OR=2.87, p=0.232). Conclusion: This study is the largest to date to present 6-month postoperative CT scans demonstrating successful TTC fusion with TCMS augmentation, contributing to our understanding of its utility. Given the severity of disease and bone loss in the TCMS group, it is not surprising that post-operative patient reported outcome scores differed significantly compared to the control group. TCMS augmentation can be utilized as cost effective spacers to fill large defects in TTC arthrodesis with successful union rates. Further studies are needed to evaluate the efficacy of TCMS augmented fusions as a viable substitute to custom printed cages. Figure 1: Weight-bearing anteroposterior and lateral ankle radiographs of a patient with post-traumatic ankle arthritis and previously treated chronic osteomyelitis with valgus malalignment (A). Anteroposterior and lateral ankle radiographs status post TCMS augmented TTC arthrodesis (B). Coronal and sagittal CT scans demonstrating bony union through the TCMS augment (C).

Feasibility of a Shape-Memory-Alloy-Actuator System for Modular Acetabular Cups.

Hip implants have a modular structure which enables patient-specific adaptation but also revision of worn or damaged friction partners without compromising the implant-bone connection. To reduce complications during the extraction of ceramic inlays, this work presents a new approach of a shape-memory-alloy-actuator which enables the loosening of ceramic inlays from acetabular hip cups without ceramic chipping or damaging the metal cup. This technical in vitro study exam-ines two principles of heating currents and hot water for thermal activation of the shape-memory-alloy-actuator to generate a force between the metal cup and the ceramic inlay. Mechanical tests concerning push-in and push-out forces, deformation of the acetabular cup according to international test standards, and force generated by the actuator were generated to prove the feasibility of this new approach to ceramic inlay revision. The required disassembly force for a modular acetabular device achieved an average value of 602 N after static and 713 N after cyclic loading. The actuator can provide a push-out force up to 1951 N. In addition, it is shown that the necessary modifications to the implant modules for the implementation of the shape-memory-actuator-system do not result in any change in the mechanical properties compared to conventional systems.

Fusion Rates in Tibiotalocalcaneal Arthrodesis with Tantalum Coated Metal Cup Augmentation

Category: Ankle Arthritis; Ankle Introduction/Purpose: Tantalum coated metal spacers (TCMS) have recently been utilized to fill and provide structure to large bony defects in the hindfoot. TCMS have a porous structure and elastic modulus similar to cancellous bone, increasing resistance to collapse, as well as osteoconductive properties that allow for bony ingrowth. At this time, there is still a paucity of literature assessing the use and outcomes of TCMS in foot and ankle surgery, more specifically as bridging structures for large bony defects when performing tibiotalocalcaneal (TTC) arthrodesis. This study serves to assess clinical outcomes and fusion rates of patients who underwent TTC arthrodesis utilizing intramedullary nailing with tantalum coated metal cup augmentation for large bony defects. Methods: We retrospectively reviewed the charts of 20 patients who underwent TTC fusion with TCMS augmentation at our local tertiary care center between 2015-2021. The CT scans at the six-month post-operative window were reviewed by one orthopaedic surgeon to determine the presence of bony fusion, which was defined as having at least 50% fusion mass. From the initial cohort, we collected the following modified foot function index scores for 13 patients: PROMIS Physical Health (0-20), PROMIS Mental health (0-20), Foot Function Index (0-170), Activity Limitation Scale (0-30), Pain Scale (0-50) and Disability Scale (0-90). Results: The mean age of our cohort was 53.9 (± 12.9) with a mean CCI of 1.54 (± 1.127) and mean follow up of 451.5 days (± 353.3). Mean modified foot function index scores included: PROMIS Physical Health 12.15 (± 3.34), PROMIS Mental health 12.23 (± 4.82), Foot Function Index 91.08 (± 47.59), Activity Limitation Scale 15.00 (± 10.42), Pain Scale 25.00 (± 14.77) and Disability Scale 51.00 (± 25.06). The post-operative complication rate was 30.8% in which 3 patients required a revision surgery via nail dynamization and one patient required a below knee amputation due to an infected nonunion of the TTC arthrodesis. The overall fusion rate at the 6-month postoperative visit was 69.2%. Conclusion: Unlike prior studies, we were able to obtain 6-month post-operative CT scans to delineate successful fusions with a larger number of patients (n=13). Given the paucity of literature looking at TCMS augmented fusions in foot and ankle surgery, our data will contribute to our understanding and efficaciousness of this relatively new use of TCMS in foot and ankle surgery. Further studies are needed to evaluate the efficacy of TCMS augmented fusions as a viable surgical approach as well an alternative to standard nail dynamizations with structural grafts.

Investigation of Sheet Thickness and Punch Force in Die Surface Angled Hydro-mechanical Deep Drawing Method

In this study, the effect of die surface angled hydro-mechanical deep drawing method (HMDDM) on sheet metal cup wall thickness and punch force was investigated as experimental and numerical analysis. In the works, 0.9 mm thick DIN EN 10130-1999 sheet metal material was used. The effect of variables on the test results was investigated by using die surface/blank holder angle, punch nose radius, die shoulder radius, chamber pressure and blank holder force as experimental parameters. Numerical analysis experiments were carried out using ANSYS 15.0 package program. Besides, experiments were performed according to the Taguchi experiment plan and L18 orthogonal array. The obtained data were analysed statistically by ANOVA analysis of variance in MINITAB 17.0 package program, and the effect of each parameter on the results was determined as a percentage. As a result, it was determined that the thinning was approximately 15% at most and the thickening was 10%.

Predicting and improving the novel process parameters involved in deep drawing process of Inconel 718 sheet at room temperature using hybrid DNN-SSO approach

The deep drawing technique is an important metal forming processes, and it is rarely used in the Inconel 718 sheet. The main purpose of this study is to perform a deep drawing process using the Inconel 718 alloy. In this research article, the Inconel 718 alloy sheet of 1 mm thickness is drawn into sheet metal cups, and defects such as thinning, and earing are controlled using selected input parameters such as Blank Holding Force (BHF) Blank Diameter (BD), and Punch Nose Radius (Rpn). A Box Behnken design (BBD) is used to evaluate the effects of output parameters. The hybrid Deep Neural Network (DNN) is used to predict the experimental outcomes obtained from the deep drawing process. For deep drawing process blank holding force is favorable for both thinning and earing. The minimum thinning value obtained during experimentation is 0.033 mm. During experimentation less earing value is 2.47 mm. Hybrid Deep Neural Network based Sparrow Search Optimization (DNN-SSO) gives the prediction model, where the values are much closer to the experimented model than RSM and non-Hybrid DNN. The minimum thinning obtained in the prediction model such as RSM, SSO-DNN, and DNN are 0.030, 0.0304, and 0.023 mm. Likewise, the minimum earing obtained from the predictive model is 2.65, 2.49, and 2.51 mm respectively. The minimum error is found in the hybrid DNN and the average RMSE for thinning is 0.002 and earing is 0.0024. The regression coefficient of thinning and earing is 99% which proves the experimental outcomes matches with RSM validation.

The current treatment of hip arthroplasty revision: a systematic review of the literature.

Acetabular revision surgery is the most challenging aspect in hip prosthetic. There is lackof consensus onthe optimal methodof reconstructingthe acetabular defects. The aim of this systematic review is to take stock of the state of the art on the options available and highlight which type of construct is the most reliable in usual clinical practice. The reporting of this systematic review was guided by the standards of the Preferred Reporting Items for Systematic Review and Meta-Analysis 2020 Statement.Electronic search of MEDLINE was performed from 1991 up to April 2021 to identify relevant studies for this review. Discussion: various surgical techniques have been adopted and proposed to treat acetabular bone defects: cemented cups, large-sized non-cemented acetabular cups, higher positioned cups, reinforcement rings, cage, oblong cups, custom triflange implants, high porous metal cups and augments. Bone defect defines the type of components to be implanted and among those, outcomes are various depending on the study taken into account, the component used and the degree of initial bone defect. In acetabular revision surgerythe use of TM cups and augment is a valid option in presence of major bone loss and pelvic discontinuities. In clinical practice the use of TM components replaced rings, while the cup-cage implant replaced conventional cages. TM augments and cups can be considered as the most promising technique in the reconstruction of wide acetabular defects, while the use of cages can be considered as a valid option in the elderly population.

LONG-TERM FOLLOW UP OF THE CUP-CAGE RECONSTRUCTION FOR PELVIC DISCONTINUITY

Pelvic discontinuity is a separation through the acetabulum with the ilium displacing superiorly and the ischium/pubis displacing inferiorly. This is a biomechanically challenging environment with a high rate of failure for standard acetabular components. The cup-cage reconstruction involves the use of a highly porous metal cup to achieve biological bone ingrowth on both sides of the pelvic discontinuity and an ilioischial cage to provide secure fixation across the discontinuity and bring the articulating hip center to the correct level. The purpose of this study was to report long term follow up of the use of the cup-cage to treat pelvic discontinuity.All hip revision procedures between January 2003 and January 2022 where a cup-cage was used for a hip with a pelvic discontinuity were included in this retrospective review. All patients received a Trabecular Metal Revision Shell with either a ZCA cage or TMARS cage (Zimmer-Biomet Inc.). Pelvic discontinuity was diagnosed on pre-operative radiographs and/or intraoperatively. Kaplan-Meier survival analysis was performed with failure defined as revision of the cup-cage reconstruction.Fifty-seven cup-cages in 56 patients were included with an average follow-up of 6.25 years (0.10 to 19.98 years). The average age of patients was 72.09 years (43 to 92 years) and 70.2% of patients were female. The five year Kaplan-Meier survival was 92.0% (95% CI 84.55 to 99.45) and the ten year survival was 80.5% (95% CI 58.35 to 102.65). There were 5 major complications that required revision of the cup-cage reconstruction (3 infections and 2 mechanical failures). There were 9 complications that required re-operation without revision of the cup-cage reconstruction (5 dislocations, 3 washouts for infection and one femoral revision for aseptic loosening).In our hands the cup-cage reconstruction has provided a reliable tool to address pelvic discontinuity with an acceptable complication rate.

Ingenuity in the Making: Matter and Technique in Early Modern Europe ed. by Richard J. Oosterhoff, José Ramón Marcaida, and Alexander Marr

Reviewed by: Ingenuity in the Making: Matter and Technique in Early Modern Europe ed. by Richard J. Oosterhoff, José Ramón Marcaida, and Alexander Marr Karel Davids (bio) Ingenuity in the Making: Matter and Technique in Early Modern Europe Edited by Richard J. Oosterhoff, José Ramón Marcaida, and Alexander Marr. Pittsburgh: University of Pittsburgh Press, 2021. Pp. 382. "Ingenuity" was a commonplace term in early modern Europe. References abound in the arts and sciences of the time, although the meaning of the word could differ widely. Historians have scrutinized the concept from various angles, especially studying the history of engineering, the history of rhetoric, and the development of art theory. While acknowledging the important insights produced by these established lines of inquiry, the editors of this volume nonetheless claim that a fresh perspective is needed. The history of ingenuity has in their view been too much subordinated to the history of genius. They aim to redirect research on the subject by looking at all kinds of makers, whether geniuses or not, and probing into the many different ways in which makers engaged with matter and designed ingenious objects. The volume thus offers a very diverse set of papers. There are essays on mining literature, calligraphy, anatomy, medical training, alchemy, the role of vapors in the philosophy of Francis Bacon, the meaning of gems in the writings of Robert Boyle, the uses of minerals set in elaborate metal cups in the shape of coconuts, sculptures with movable parts as an aid to devotion, sundials in Renaissance gardens, and a magical lamp burning human blood described by alchemist Johann Ernst Burggrav. Finally, there are a few contributions that examine changes in the concept of ingenuity over time and how Europeans reflected on, or appropriated, specimens of ingenuity produced in other parts of the world. Sixteen beautiful color plates accompany the texts. All essays are paragons of erudition. All of them are very learned and a pleasure to read. Readers are nevertheless left wondering what this variety of well-crafted case studies eventually contributes to a better understanding [End Page 259] of the concept of ingenuity, apart from the observation that ingenuity in the early modern period was an even more complex and pluriform concept than previously thought. Ingenuity not only had to do with genius—that is a hard fact the contributions in this volume make abundantly clear. However, it would have been helpful if the editors had added a concluding analysis uncovering some patterns in the wealth of empirical evidence. The essay that comes nearest to such an analytical approach is Marieke Hendriksen's excellent piece on the shift of concepts in eighteenth-century theories of art and craft. Hendriksen concentrates on the demise of ingenuity and the rise of genius and technique in German thinking about the visual arts around 1800. She argues that ingenuity lost its central role in art theory as the need arose for a new language to distinguish innate talent and acquired skill in the appreciation of fine art. Genius became the preferred designation for the former, technique for the latter. The concept of ingenuity, which intersected the mind-hand distinction, was not suitable for this purpose, but it retained its use in other areas where making and knowing were seen to be interconnected, such as engineering. Hendriksen's essay also leads us to a fundamental question that the editors, alas, do not address in their introduction. Granted that the concept of ingenuity in the early modern period could be applied to so many makers and artifacts, did it actually have any limits at all? Were there any restrictions to its use? Perhaps there were—if you read between the lines. Although the words "craft" and "artisans" appear a few times in this volume, the case studies do not refer to guilds or guildsmen, nor does the index. None of the case studies discuss the relevance of guild rules for makers or artifacts, which have been the subject of a growing body of historiography of late. The discourse on ingenuity in the early modern period was apparently completely removed from the world of guilds, even if these organizations remained key institutions in many European economies...

Localization of the ilioischial line on axial computed tomography images for preoperative planning of total hip arthroplasty

BackgroundIf the bony region indicating the ilioischial line is established on the preoperative axial computed tomography (CT) image, the distance between the simulated cup and the ilioischial line can be measured on this image so that the surgeon can use these data to define a more accurate preoperative two-dimensional (2D) template of total hip arthroplasty (THA). This study aimed to verify the hypothesis that on the CT axial image, the cortical bone area, indicated by the superimposition of a line (line α) with a perspective projection angle to the ilioischial line on radiography and tangent to the medial acetabular wall, is the cortical bone that represents the ilioischial line on radiography.MethodsStudy 1: If the two measured distances (distance A’ and distance B) are sufficiently equal, then the hypothesis can be supported. Distance A’ was calculated by multiplying the distance A, between the ilioischial line and the medial margin of the metal cup after THA measured at the level of the hip joint center on the pelvic radiograph, by 0.91 to correct for radiographic magnification. Distance B was defined as the distance between the medial margin of the metal cup and line α on the axial CT image at the level of the hip joint center. These two distances were measured for all 51 hip joints included in the study.Study 2: The difference between distance A and distance A# (distance A on the 2D template) was compared between the group containing 59 primary THAs in which distance B′ was measured (distance B in the simulation) and the control group containing 59 primary THAs.ResultsStudy 1: The average distance for A’ was 4.5 ± 2 mm, and the average distance for B was 4.7 ± 2.1 mm. The difference between distances A and B was 0.2 ± 0.2 mm.Study 2: The mean difference between distance A and distance A# for the measurement and control groups was 1.8 ± 1.3 mm and 3.7 ± 2.4 mm, respectively (P < 0.001).ConclusionsThe ilioischial line is located in the bony region where line α intersects the medial acetabular wall with a maximum overlap on axial CT images.

Denosumab prevents acetabular bone loss around an uncemented cup: analysis of secondary outcomes in a randomized controlled trial.

Background and purposeUncemented total hip arthroplasty (THA) is associated with periprosthetic bone loss. In a secondary outcome analysis from a randomized controlled trial, we studied whether denosumab can prevent loss of acetabular periprosthetic bone mineral density (pBMD) in patients who received a trabecular metal cup during uncemented THA.Patients and methods64 patients (aged 35–65 years) with unilateral osteoarthritis of the hip were randomized to 2 subcutaneous injections with denosumab or placebo, given 1–3 days post-surgery and 6 months post-surgery. Acetabular pBMD was measured in 5 regions of interest (ROIs) by dual-energy X-ray absorptiometry. Serum markers for bone metabolism were analyzed. Periprosthetic osteoblastic activity, measured as standardized uptake values (SUVs) by [18F] positron emission tomography/computed tomography, was evaluated in 32 of the 64 study patients.ResultsAfter 12 months, patients treated with denosumab had higher pBMD compared with the placebo-treated patients in 4 of 5 ROIs and in sum of ROIs 1–5. After 24 months, the effect on pBMD for patients treated with denosumab declined. Serum markers declined pronouncedly up to 12 months in patients treated with denosumab, but rebounded above baseline levels after 24 months. Patients treated with denosumab had statistically significantly lower SUVs in all ROIs, except ROI 5, after 6 months.InterpretationBased on this exploratory analysis of secondary endpoints the application of denosumab seems associated with preserved acetabular pBMD, reduced bone metabolism and attenuated periprosthetic osteoblastic activity. However, given the known rebound affects after discontinuation of denosumab treatment, these effects cannot be expected to persist. If prolonged treatment or shift to other regimes would be beneficial to reduce the risk of cup loosening is yet to be investigated.

Dry and Wet Lubrication Analysis for Multi-Material Hip Assembly

Hip joint repair/replacement is one of the most thriving orthopedic surgical procedures in the human body. The group of patients undergoing hip replacement considerably includes young and physically active persons with varying movements thus requiring longer product life and ease of maintenance. Perfect lubrication in hip assembly ensures a low wear rate and better product life. The present work focuses on dry and wet lubrication analysis of complete implant assembly instead of an individual part. The assembly consists of a stem, head, liner and cup, each made of different materials like a ceramic femoral head mounted over a metallic femoral stem with a polyethylene liner and a metallic acetabular cup. In this work, eight metal-materials are considered for stem/cup, three ceramic materials for the head and two polyethylene materials for the liner. The combinations of these materials are evaluated for various mechanical parameters. Dry (µ = 0.13) and wet (µ = 0.05) lubricating conditions between the liner and femoral head have been considered and their effects on the head, liner and cup have been evaluated for the optimization of Hip joint design. Fifty percent of re-surgery cases arise because of excessive wear out resulting in aseptic loosening of the femoral head and liner interface. Femoral head of size 28 mm diameter with 2 mm thick liner and 3 mm thick acetabular cup are modeled and are analyzed for axial pay load of 2.3 kN. The maximum von mises stress and total deformation for various material combinations of implant assembly have been compared to select the most suitable one for the arthroplasty implantation. The combination of CoCrMo – Ceramics – HXLPE – CoCrMo demonstrates minimum stress and deformation for all three parts i.e. femoral head, liner and acetabular cup under present loading and boundary conditions. ZTA is emerged as the preferred ceramic material for femoral head having a higher compressive strength.

Ultrasensitive Capacitive Sensor Composed of Nanostructured Electrodes for Human–Machine Interface

AbstractHuman–machine interface requires various sensors for communication, manufacturing and environmental control, and health and safety monitoring. Capacitive sensors have been used to detect touch, distance, geometry, electric property, and environmental parameters. However, highly sensitive proximity detection with a small form factor has always been a challenge. This paper presents a capacitive sensor composed of a nanostructured electrode array for contact and noncontact detection. In the sensor configuration, the nanostructured electrode is made of high aspect ratio cellulose fibers embedded with carbon nanotubes. The complementary electrode is designed to be smaller in surface area for high sensitivity. Based on the analysis, the unique sensing mechanism is shown to enhance the proximity sensitivity for target detection. A pair of asymmetrically designed electrodes are characterized and compared with the traditional symmetric electrodes for proximity and contact detection of human hands. The sensor performance is also characterized for detecting water mass in glass and metal cups. In the end, a smart pad that can recognize human gestures, gait, and water mass with unprecedented sensitivity is demonstrated.

Intraprosthetic Dislocation of Dual-Mobility Total Hip Arthroplasty: The Unforeseen Complication.

Total hip arthroplasty (THA) is one of the most successful and widely accepted orthopedic procedures. Instability after THA is one of the most significant postoperative complications. Dual-mobility THA components were introduced in 1974 to overcome the risk of instability by increasing the jump distance. Dual-mobility bearings couple two articulations, namely, one between a 22-28 mm prosthetic head and polyethylene liner and another larger articulation between the polyethylene liner and the metal cup. Dislocation of the polyethylene liner and the consequent direct articulation between the prosthetic head and metal cup is recognized as intraprosthetic dislocation (IPD). This mode of THA failure is specific to dual-mobility implants. Despite the reduced incidence of IPD in modern dual-mobility implants compared to the early designs, iatrogenic IPD can occur during closed reduction of dislocated polyethylene liner-metal cup articulation. IPD requires timely diagnosis and early surgical intervention to minimize the necessity of major revision surgeries. This study presents a comprehensive review for dual-mobility-bearing THA, including the history and biomechanics, and focuses on the pathomechanics, diagnosis, and management of IPD.

Hybrid cube-in-cup nanoantenna: towards ordered photonics

The most significant goal of nanophotonics is the development of high-speed quantum emitting devices operating at ambient temperature. In this regard, plasmonic nanoparticles-on-mirror are potential candidates for designing high-speed photon sources. We introduce a novel hybrid nanoantenna (HNA) with CdSe/CdS colloidal quantum dots (QDs) based on a silver nanocube in a metal cup that presents a nanoparticle-in-cavity coupled with an emitters system. We use focused ion beam nanolithography to fabricate an ordered array of cups, which were then filled with colloidal nanoparticles using the most simple drop-casting and spin coating methods. The spectral and time-resolved studies of the samples with one or more nanocubes in the cup reveal a significant change in the radiation characteristics of QDs inside the nanoantenna. The Purcell effect causes an increase in the fluorescence decay rate (≥30) and an increase in the fluorescence intensity (≥3) of emitters in the HNA. Using the finite element method simulations, we have discovered that the proximity of the cups wall affects the oscillation modes of the gap plasmon, which, in turn, leads to changes in the electric field enhancement inside the nanoantenna gap. Additionally, substantial variations in the behavior of the gap plasmons at different polarizations of the exciting radiation have been revealed. The proposed nanoantenna can be useful in the development of plasmonic sensors, display pixels, and single-photon sources.

Hip Instability Leading to Metallosis, Polyethylene Wear, and Failure of an Oxinium Femoral Head: A Case Report and Review of Literature

AbstractOxinium is a zirconium metal alloy with an oxidized (ceramicized) surface that aims to mimic the superior wear properties of a ceramic femoral head while maintaining the high strength of metal-bearing surfaces. There are several reports that illustrate the wear and/or failure of Oxinium femoral heads following abnormal head contact with metal cup, with only a few studies reporting on the occurrence of metallosis. We present a case of metallosis and failure of Oxinium femoral head following two incidents of hip instability and one closed reduction. Successful revision was performed with cemented cup and metal femoral head, with 68 months of follow-up. We aimed to highlight the importance of achieving stable and well-oriented hip components when using Oxinium-bearing surfaces and to present a short literature review regarding the wear of oxidized zirconium-bearing surfaces in hip arthroplasty.

Cigarette butts in beach litter: Snapshot of a summer holiday

Cigarette butts are considered the most common form of personal litter around the world. It is estimated that 5.5 trillion cigarettes are consumed globally each year and that 4.95 trillion are discarded in some natural or anthropic environment around the world. This study evaluated the pollution of urban beaches in the Brazilian Northeast by cigarette butts in relation to other types of litter. Samplings were conducted in a month of high season (January 2016), at eight heavily used beaches. In the place with the highest concentration of users in each beach, a 200 m transect (3 m width) was established parallel to the water on the most recent strandline. All items >1 cm were counted and classified into categories according to composition (plastic, cigarette butts, wood, glass, metal, paper and organic, such as food leftovers and coconuts) using a standard worksheet. Cigarette butts were considered as an isolated category of litter. A total of 10,880 items was registered. The most abundant items were plastics (44.96%) and cigarette butts (38.36%). Among plastics, the most abundant items were straws, metallic food packaging, sticks (lollipop and popsicle) and cups. Plastic fragments were also abundant in all beaches evaluated, corresponding to 14.5% of the total plastics.

Acetabular distraction hip arthroplasty in neglected transverse and T-shape acetabular fractures : a different application

Neglected acetabular fractures are often challenging to treat. The aim of this study is to highlight the technique of acetabular distraction with porous metal cup as a viable technique to address such complex cases. This is a prospective study of seven patients who had neglected acetabular fracture or fracture non-union that were managed with total hip arthroplasty using acetabular distraction and porous metal cup with cemented liner. The average age of the patients was 51 years (range 36-58 years). Average time of follow up was 18 months (range 12-36 months). Radiological results at latest follow up and by comparing serial radiographs showed that all cases had a well-fixed implant construct without evidence of loosening or malorientation. Average Harris hip score pre-operatively was 46, which improved to an average of 84 post-operatively. Our study shows that total hip replacement using acetabular distraction with porous metal cup provide early good results in reconstruction of acetabular bony deficiencies due to neglected acetabular fracture.

Maternal and Neonatal Outcomes of Operative Vaginal Deliveries at a Single Tertiary Center.

ObjectivesOur study sought to assess the maternal and neonatal outcomes of operative vaginal deliveries (OVDs) at Sultan Qaboos University Hospital (SQUH). We assessed the proportion of OVDs along with the proportion of maternal and neonatal outcomes of kiwi OmniCup vacuum, metal cup vacuum, and forceps deliveries.MethodsWe conducted a retrospective cohort study in the Obstetrics and Gynecology Department at SQUH from June 2015 to March 2018. The hospital information system was utilized to obtain records of all women who delivered at SQUH by vacuum or forceps during the study period. We collected data on maternal demographics, maternal and neonatal outcomes, and total number of deliveries.ResultsDuring the study period, 3.8% of deliveries were OVDs. The most common instrument used was the Kiwi OmniCup vacuum device. No significant difference was found between the type of tears and instrument used except perineal tears (p = 0.003), which was seen more in the vacuum group, particularly Kiwi OmniCup. Neonatal birth weight (p = 0.046) was significantly higher in the metallic vacuum cup group. Thirty-one neonates (6.6%) were admitted to the neonatal intensive care unit, and most were born using Kiwi OmniCup vacuum (67.7%).ConclusionsOVD is an ideal alternative to cesarean section with fewer maternal and neonatal complications in women who cannot deliver spontaneously if performed by a well-trained obstetrician.