Titanium Sleeve Research Articles

Ceramic Heads With 12/14 Titanium Sleeves Used on Manufacturer-Non-Compatible Retained Femoral Components Do Not Lead to Implant Failure in Revision Hip Arthroplasty

BackgroundCeramic femoral heads with titanium sleeves are commonly used in revision total hip arthroplasty (rTHA). Companies advise against combination with a retained femoral component from another manufacturer. However, no data are available. The aim of this study was to evaluate and compare the implant failure and revision rates of ceramic heads with a 12/14 titanium sleeve used on manufacturer-compatible versus noncompatible retained femoral components. MethodsA retrospective single-center cohort analysis was performed using a prospectively maintained institutional arthroplasty registry. We identified 439 patients who received a titanium 12/14 ceramic head during rTHA between January 1, 2007, and December 31, 2022. There were 229 manufacturer-compatible and 210 manufacturer-noncompatible retained femoral stems, according to the company's official product compatibility list. Implant failure and rerevision rates were evaluated. ResultsAfter a median follow-up of 6.6 years (IQR (interquartile range): 4.5 to 9.3), there was no significant difference (P = 0.770) in the rerevision rate between the manufacturer-compatible group (17.0%) and the noncompatible group (18.1%). Revision-free survival after rTHA was 81.2% in the manufacturer-compatible group and 78.9% in the manufacturer-noncompatible group after 15 years (P = 0.653). Most rerevisions occurred in the first year after rTHA, with 29 of 229 (12.7%) in the manufacturer-compatible group and 24 of 210 (11.4%) in the manufacturer-noncompatible group (P = 0.705). We observed only one implant failure in the manufacturer-noncompatible group, but this was not related to a mismatch problem. ConclusionsAlthough legal uncertainties remain, this study showed no increased risk of implant failure or revision rates when a ceramic femoral head, with a 12/14 titanium sleeve, was used on a noncompatible femoral stem from a manufacturer.

New Ceramic Heads With Titanium Sleeves on Retained Femoral Components: Results of Over 500 Revision Total Hip Arthroplasties

BackgroundCeramic heads are frequently combined with titanium sleeves in revision total hip arthroplasties (THAs), ostensibly to protect the ceramic head from existing damage to the retained trunnion. Although widely adopted, data on the performance and safety of this construct are minimal. The purpose of this study was to describe implant survivorships, radiographic results, and clinical outcomes of patients who underwent revision THA with a ceramic head and titanium sleeve on a retained femoral component. MethodsWe identified 516 revision THAs with femoral component retention (328 acetabular-only revisions and 188 bearing surface exchanges) treated with a new ceramic head and titanium sleeve between 2000 and 2020. Mean age at revision was 64 years, 56% were women, and mean body mass index was 30. The indications for revision THA were adverse local tissue reaction (25%), acetabular loosening (24%), dislocation (17%), infection (5%), and other (29%). Kaplan-Meier survivorships were analyzed, radiographs reviewed, and Harris Hip Scores evaluated. Mean follow-up was 4 years (range, 2 to 10). ResultsThere were no reoperations or failures for ceramic head fracture, taper corrosion, or head/sleeve disengagement. The 10-year survivorship free of any re-revision was 85%. Indications for the 57 re-revisions included dislocation (33), infection (13), acetabular component loosening (7), periprosthetic fracture (2), psoas impingement (1), and sciatic nerve irritation (1). The 10-year survivorship free of any reoperation was 82%. There were an additional 14 reoperations. Radiographically, 1.9% had progressive femoral radiolucent lines, and 4.7% had progressive acetabular radiolucent lines. Mean Harris Hip Score was 81 at 2 years. ConclusionsNew ceramic heads with titanium sleeves in revision THAs with retained femoral components were durable and reliable with no cases of ceramic head fracture or taper complications at mean 4-year follow-up, including those revised for adverse local tissue reaction. Level of EvidenceIV.

Изучение возможностей углеродного материала в паре трения эндопротеза тазобедренного сустава при помощи математического моделирования и стендовых испытаний

INTRODUCTION: One of the most effective methods of surgical treatment of late-stage coxarthrosis is total hip replacement. However, the steady increase in the number of primary endoprosthetics results in the increase of revision surgeries. Our proposed solution to use carbon material in bearings will decrease the number of revision surgeries due to component wear, and may also significantly reduce the risk of aseptic loosening. AIM: To compare stress and torque of the head and liner structures with bearings made of carbositall with diameters of 28 mm and 38 mm using mathematical modeling and to compare the volume wear of bearings made of ceramics and carbositall using bench tests. MATERIALS AND METHODS: Mathematical modeling was used to assess the stresses in the proposed design. The mathematical model was created by software-based methods in ANSYS 5.7 environment. Structures with diameters of 28 mm and 38 mm were studied. A physical model of a bearing made of carbositall was made for bench testing. In accordance with requirements of GOST 31621-2012, a torque test of a carbositall bearing was performed. In accordance with GOST R ISO 14242-3-2013, a study of volume wear of bearings made of ceramics and carbositall was performed. RESULTS: Mathematical modeling of a bearing made of carbositall with a size of 38 mm in comparison with a bearing with a diameter of 28 mm showed a decrease in intensity of compressive and tensile stresses with a natural increase in the safety factor for components made of carbositall. Based on the results of the torque test of bearing for hip arthroplasty, the torque was 1.1 Nm. This indicator is 26.6% lower than the maximum permissible according to GOST 1.5 Nm. The torque index was 1.10 Nm. As a result of a comparative test for wear of bearing made of ceramic and carbositall, the mass loss of the ceramic head was 0.009 g, the mass loss of the ceramic liner was 0.013 g. The head made of carbositall lost 0.006 g, while the liner lost 0.009 g. In total, the mass loss of the carbon bearing is 31.8% less than that of the ceramic one. CONCLUSION: A large-diameter bearing showed the best strength characteristics of the carbon part of the structure, however, the strength limit of the titanium sleeve decreased. The torque of the carbon bearing was 1.1 Nm, which is 26.6% lower than the maximum permissible index, and the volume wear of the bearing made of carbositall is 31.8% less than the volume wear of the bearing made of ceramics.

The Effect of Novel Complex Treatment of Annealing and Sandblasting on the Microstructure and Performance of Welded TA1 Titanium Plate

The welding titanium cathode roller has the obvious advantages of low cost, high efficiency, and no diameter restriction. Unfortunately, the longitudinal weld on the cathode roller adversely impacts the quality of the electrolytic copper foil due to the great difference between the microstructure of the weld zone and the base metal. Thus, it is crucial to reduce their difference by regulating the microstructure of the weld zone. In this study, a novel complex treatment of heat treatment and sandblasting is primarily developed for regulating the microstructure of the weld zone. The results show that the novel complex treatment has an efficient effect on regulating the microstructure of the weld zone and making the microstructure in the weld zone close to that of the base metal. During vacuum annealing, the microstructure of the weld zone is refined to some degree, and 650 °C annealing has the optimal effect, which can effectively reduce the ratio of α phase's length to width and reduce the microstructure difference between the weld zone and the base metal. At the same time, with an increase in the annealing temperature, the tensile strength and yield strength decreased by about 10 MPa; the elongation after fracture increased by 20%; the average microhardness of the WZ and the HAZ decreased by about 10 HV0.10; and that of the BM decreased by about 3 HV0.10. The heat treatment after welding can effectively adjust the properties of the weld zone, reduce the hardness and strength, and improve the toughness. The subsequent sandblasting after annealing can further refine the grain size in the weld zone and make the microstructure in the weld zone close to that of the base metal. Sandblasting after annealing can further refine the grain in the weld zone and make the microstructure in the weld zone close to that of base metal. Meanwhile, an application test confirmed that the adverse impact of a longitudinal weld on the quality of electrolytic copper foil could be resolved by adopting this novel complex treatment. Therefore, this study provides valuable technical support for the "welding" manufacturing of the titanium sleeves of the cathode roller.

A Modular Head-Neck Adapter System and Ceramic Heads in Revision Hip Arthroplasty: A Registry Study on 354 Implants

BackgroundFive- to 10-year outcomes of a modular head-neck adapter system with ceramic heads in revision hip arthroplasty on large populations are still lacking. A registry study about modular adapter system with Delta ceramic head in revisions was designed, aiming to assess (1) the survival rates of the device, (2) the reasons for re-revisions of the device, and (3) a comparison to factory assembled titanium sleeve and Delta head cohort in revision hips. MethodsUsing a regional arthroplasty registry, we investigated the modular adapter system with a ceramic head in revision hips. Demographics, implant features, and reasons for revision were recorded. Survival rates and reasons for re-revision were assessed. The modular adapter system with the ceramic ball was compared to a factory-assembled ceramic titanium-sleeved head in revisions, acting as a control group. There were 354 revisions included at a mean follow-up of 5 years (range, 0 to 13). ResultsThe 5- and 7-year survival rates were 87.9% and 86.9%, respectively. Dislocations (2.8%) and cup aseptic loosening (4.2%) were the 2 most frequent reasons for re-revision. No breakage of the adapter system or the ceramic head occurred. A femoral neck failed (0.3%). No implant features, offset (P = .088) or skirted (P = .870) tapers, impacted on failures. No differences between the 2 cohorts were found regarding survival rates (P = .696) and reasons for re-revision (dislocations, P = .983; cup aseptic loosening, P = .296). ConclusionThe modular head neck adapter system with a ceramic head seems to be a valid option in revisions at 5 and 7 years, without additional risk of implant breakage in this registry.

Prosthetic Complications of Screw-Retained Restoration Using Multiunit Abutments Versus Intraoral Luting on Titanium Base in Implant-Supported Complete Overdentures Randomized Clinical Trial

BACKGROUND: This trial aims to study the difference between prostheses screwmented on full-arch implants using the intraoral luting cement technique on titanium bases versus transmucosal abutments in terms of prosthetic complications. MATERIALS AND METHODS: Twenty patients were recruited in this trial, there were mainly two groups. A screw-retained full-arch implant-supported prosthesis was constructed over four dental implants on upper or lower jaws. For the control group, multiunit abutments were used to construct a screw-retained prosthesis. As for the experimental group, Ti-base abutments were used over the dental implants to construct a screw-retained prosthesis. In both groups, the prosthetic framework was made using polyether ether ketone (PEEK) material and luted intraorally over the titanium sleeve using resin cement. A binary outcome of prosthetic complication was taken in 6 and 12 months. Abutment screw loosening, prosthetic screw loosening, prosthetic screw fracture, abutment screw fracture, veneer fracture, framework fracture, Ti-base decementation, and overall prosthetic loosening were the prosthetic complications included in the trial. RESULTS: At the end of the study, a total of 19 patients adhered to the trial. Throughout the exposure process of implants, two implants failed in one patient from the Ti-base group. This patient was excluded from the study on his request. There was no statistically significant difference present between Ti-base and multiunit abutment groups in terms of abutment and prosthetic screw loosening, abutment and prosthetic screw fracture, veneer and framework fracture, Ti-base decementation, and overall prosthesis loosening for 6 and 12 months. Data were explored for normality using Kolmogorov–Smirnov and Shapiro–Wilk tests, data showed non-parametric (not-normal) distribution. Qualitative data were presented as frequencies and percentages. Wilcoxon and Mann–Whitney tests were used to compare the qualitative outcomes in this study. CONCLUSION: Both multiunit and Ti-base are considered a viable line of treatment to construct a screw-retained full arch implant-supported prosthesis.

Effect of femoral head material on head-to-trunnion impaction motion and taper.

The purpose of this study was to evaluate the effect of femoral head material on the impaction force, relative motion, and stability of the trunnion. There were three groups with different head materials (n = 5 per group)-CoCr Group: 36 mm CoCr heads, Ceramic Group: 36 mm ceramic heads, Ceramic + Sleeve Group: 36 mm ceramic heads with a titanium sleeve-that were all impacted twice and disengaged onto titanium alloy (Ti6al4V) trunnions in in vitro conditions. A high-speed camera system was utilized to characterize relative displacement behavior of the head-trunnion junction motion. The first impact force of Ceramic + Sleeve Group (14,241 SD, 935) was significantly lower than the first impact force in Ceramic Group (14,961 N, SD = 184). Ceramic + Sleeve Group had a lower magnitude bounce-back displacement following the first impact (17.7 μm, SD = 11), p < 0.05) compared to CoCr Group (298.8 μm, SD = 84) and Group 2 (196.5 μm, SD = 31). Ceramic + Sleeve Group sat further on the trunnion (cumulative final displacement, 366.8 μm, SD = 71, p < 0.001) compared to CoCr Group (142.5 μm, SD = 41.8) and Ceramic Group (183.8 μm, SD = 30). Ceramic + Sleeve Group demonstrated two distinct disengagement patterns-(a) the sleeve disengaged from the trunnion (pull-off force 6810 N), and (b) the femoral head disengaged from the sleeve (pull-off force 18,620 N), with large fluctuations in pull-off force. The presence of a titanium sleeve with a ceramic head resulted in significant differences in impaction force on the trunnion, motion and displacement, and unique mechanisms for disengagement. Further investigation is required to determine potential clinical impact.

Fatigue Evaluation of a New Two-Piece Dental Implant, Having a Replaceable Titanium Sleeve

Abstract A new two-piece dental implant, having a replaceable thin titanium sleeve in its 5 mm crestal part was designed. The use of a sleeve of near 0.2 mm thickness reduces implant diameter by 0.4 mm. Narrower diameter implants may increase the likelihood of component fracture in dental implant systems. 14 two-piece dental implants, with 25 deg abutment angle were subjected to a dynamic fatigue test according to DIN EN ISO 14801. The highest load at which a runout (nonfailure) occurred at 5 × 106 cycles, amounted to 575 N. This load level was confirmed with n = 3 samples. The Wöhler curve was determined. Accordingly, the runout at 106 cycles can be anticipated as 625 N. The new two-piece Implant B™ design using a 0.2 mm sleeve is compatible with the DIN EN ISO 14801 standards for dimensions of 4.2 mm diameter and 13 mm length. It withstands dynamic fatigue test at least as good as any other standard endosseous implant.

Tibial tray cementation is not necessary for knee revision with titanium metaphyseal sleeves: a mid-term prospective study in AORI 2B defects.

Metaphyseal fixation with porous titanium sleeves in revision knee surgery provides mechanical support to the implant, promotes biological fixation, and has shown satisfactory short- and mid-term results. Cement is commonly used to fix the tibial tray to the epiphyseal area. The objective of this study is to determine whether cement should be used to achieve fixation of the tibial tray with the hypothesis that metaphyseal sleeves would provide enough axial and rotational stability making cementation unnecessary. Prospective study of 60 patients undergoing knee replacement surgery with metaphyseal sleeves in type 2B defects in femur and tibia. Patients were divided into two groups according to the use of cement on the tibial component. Analysis included the American Knee Society Score (KSS) knee and functional scales, the Western Ontario and McMaster Universities (WOMAC) index, the Short Form 12 (SF-12) health survey, and radiographic assessment with a maximum follow-up of 5years. No statistically significant differences were found between the two groups in any of the parameters assessed. Metaphyseal sleeves showed a 100% survivorship at five years of followup. There were no differences in clinical and radiographic outcomes at five years of follow-up depending on whether or not cement was used for tibial platform fixation. Cementation of the tibial tray would therefore not be required to achieve satisfactory mid-term results. Level II: prospective cohort study. Therapeutic.

Positioning accuracy assessment of minimally invasive percutaneous injection techniques for the treatment of temporomandibular disorders

The aim of the present study was to evaluate the accuracy of an extraoral CBCT-planned 3D-printed surgical guide aimed to percutaneous injection of substances into the temporomandibular joint (TMJ) and the lateral pterygoid muscle (LPM). Nine human cadaver heads were used. Pre-planning CBCT and facial scans were obtained and three percutaneous injection sites were planned: one for the lower compartment of the TMJ and two for the LPM. A digital surgical guide was then designed with small titanium sleeves and printed by a 3D printer. After the injections, new CBCT scans with the needles in place were obtained in order to assess the accuracy of the procedure in relation to the virtual planning. The mean values for angle deviation were very low (range 1.13o-4.08o), the same happening for the mean difference in the length reached (range 1.82-2.64 mm), as well as for the mean difference in the needle tip dislocation (range 0.94-2.03 mm). The guide seems to be a reliable tool for accurate percutaneous injection of drugs into the inferior compartment of the TMJ and the LPM. Further studies are necessary to test the efficacy and validate the method in an in vivo study.

Adverse Local Tissue Reaction due to Mechanically Assisted Crevice Corrosion Presenting as Late Instability Following Metal-on-Polyethylene Total Hip Arthroplasty

BackgroundMechanically assisted crevice corrosion (MACC) at modular junctions can cause a spectrum of adverse local tissue reactions (ALTRs) in patients who have undergone total hip arthroplasty (THA). The purpose of this study is to describe the presentation, treatments, and related complications of a cohort of patients presenting with late instability following metal-on-polyethylene THA due to underlying MACC and ALTR. MethodsThis multicenter retrospective case series presents 17 patients (12 women, mean age 62.6, range 42-73) presenting with late instability secondary to ALTR and MACC. All patients had a metal (Cobalt Chrome)-on-polyethylene bearing surface. Patients experienced a mean 2.7 dislocations (range 1-6) at mean 4.3 years (range 0.4-17.0) following their index surgery. Serum metal levels (n = 12) demonstrated a greater elevation of cobalt (mean 6.9, range 0.13-20.88 ng/mL) than chromium (mean 1.9, range 0.13-3.23 ng/mL). ResultsPatients were revised for instability at a mean of 6.8 years (range 2.1-19.4) following their index surgery. ALTR was encountered in every case and the modular head-neck junction demonstrated visible corrosion. An exchange of the CoCr head to a ceramic head with a titanium sleeve and placement of a constrained liner was performed for a majority of patients (n = 15, 88.2%). Five patients (29.4%) had complications postoperatively including peroneal palsy (n = 2), periprosthetic joint infection (n = 2), and ALTR recurrence (n = 1). ConclusionRecurrent instability in the setting of otherwise well-positioned THA components and without another obvious cause should raise concern for ALTR as a potential underlying etiology.

Analysis and Design of Novel High Speed Permanent Magnet Machine Considering Magnet Eddy Current Loss

In high speed permanent magnet (HSPM) machines, the computation of magnet eddy current loss is essential as these losses significantly affect the temperature of the permanent magnet (PM) and electromagnetic performance and can result in irreversible demagnetization of the PM. Several techniques have been adopted to minimize the eddy current loss of the PM; however, superior performance has not been achieved yet. In this paper, the design characteristics of the HSPM machine are analyzed. The PM is covered by a titanium sleeve to retain the PM on the rotor and to further reduce the eddy current loss of the magnet. The undesirable harmonics of the airgap flux density are minimized, which reduces the eddy current loss in the solid PM and rotor. Two existing models, with and without auxiliary slots, are examined and compared with the proposed design having a titanium-based retaining sleeve. The analysis reveals that the eddy-current loss, cogging torque, and iron losses of the PM are reduced by 82%, 73%, and 44.7%, respectively, in the proposed model; however, a marginal increase is observed in the average rated torque profile and open circuit flux linkage.

Impact of stem taper damage on the fracture strength of ceramic heads with adapter sleeves

BackgroundUsing a new ceramic head with a titanium adapter sleeve offers the possibility of maintaining a well fixed stem when conducting cup revision of a total hip arthroplasty. The aim of this study is to test the impact of stem taper damage on the fracture strength of sleeved ceramic heads. MethodsPristine zirconia-toughened alumina heads with titanium adapter sleeves (BIOLOX®OPTION System) were tested on damaged Ti-4Al-6V stem tapers in accordance with ISO7206-10. Four distinctive damage types classified as intolerable by the manufacture were investigated, representing various reductions in contact area between the stem taper and sleeve taper as well as damage incurred from previous ceramic head fracture. FindingsThe largest reduction in fracture strength occurred for a loss of contact for the entire length of the stem taper. Nonetheless, the fracture strength in all investigated cases was several times higher than that defined by the FDA standards. InterpretationThe use of a titanium sleeve recreates a uniform contact situation between the ceramic head and the outer sleeve taper in situations of damaged stem tapers. For the investigated damage types a high fracture strength of the ceramic head was maintained. This study supports the clinical use for sleeved ceramic heads in instances of greater damages of stem tapers than previously defined in order to spare patients from stem removal.

Effects of corrosion and cleaning method on taper dimensions: an in vitro investigation.

Taper corrosion related revisions have recently been reported in the orthopaedic literature. Cleaning procedure of the trunnions during hip revision is not standardised. The purpose of this bench top investigation was to understand the alterations in the trunnion dimensions and surface roughness characteristics as a result of corrosion product build-up. 8 titanium alloy trunnions and CoCr femoral heads assemblies were cyclically tested in a mechanical simulator. Following disassembly of the tested constructs, the trunnions were cleaned using 2 methods. The trunnion dimensions were measured using coordinate measuring machine, and surface roughness was measured using white light interferometry. The trunnions were reassembled with ceramic femoral heads and titanium sleeves following cleaning. Head/sleeve pull-off testing was conducted to understand the effects of cleaning methods on the pull-off strength. Grade 4 corrosion was observed on all trunnions after mechanical testing. The aggressive cleaning methods had a larger impact on the surface roughness when compared to the light cleaning method. The aggressive cleaning method also decreased the taper cone angle. The pull-off strength was not affected by the cleaning method and the pull-off values were approximately 50% of the assembly loads. The study suggests that trunnion cleaning method may alter the surface roughness and taper cone angle of the existing trunnion. However, the effects of these changes on the pull-off strength did not reach statistical significance. Complex corrosion testing under cyclic loading conditions are warranted to understand the long-term effects of these changes.

A two-piece dental implant comprising a replaceable thin titanium sleeve may be a new approach to re-osseointegration following peri-implant disease

Bacteria initiated peri-implantitis can lead to bone destruction around a dental implant, modifying its surface and preventing re-osseointegration. Consequently, all available methods for treating periimplantitis have disappointing long-term results. Implant failure will lead to loss of the prosthetic reconstruction as well. A fresh new implant surface enables re-osseointegration. Our hypothesis is that a fresh new surface replacing a contaminated implant surface may be a new treatment approach for peri-implantitis and may allow re-osseointegration. A new two-piece dental implant, having a replaceable thin titanium sleeve may be designed. The replacement of a contaminated sleeve by a fresh new sleeve will solve the peri-implant disease by removing the contaminated surface, enabling re-osseointegration and ensuring long-term stability of the implant without endangering the prosthetic reconstruction. This minimally-invasive therapy is expected to be conducted in a simple manner, by every practicing dentist, during supportive periodontal treatment, thereby facilitating the treatment of peri-implantitis.

Bone loss management: A potpourri of options

Bone loss encountered during revision TKA can make proper alignment and fixation a challenge. Causes for bone loss in revision TKA include implant loosening, osteolysis, and iatrogenic from implant removal. Reproducible clinical success can be achieved if metaphyseal fixation is achieved [1]. In the absence of cancellous bone for cement fixation, metaphyseal augments placed without cement have shown promise in achieving fixation. First generation augments were modular solid titanium sleeves attached to a taper at the base of the core implant. The introduction of tantalum with its favorable mechanical qualities markedly increased the utility and utilization of metaphyseal augments, with several encouraging reports. These are either large augments where the bone is prepared with a burr, or later, small cones placed with a cannulated broaching technique. Both have addressed practical challenges, the first being limited by the reproducibility of bone preparation, and the second with excellent reproducibility of bone preparation but limited inner diameters. More recent highly porous titanium surfaces have further broadened the choices by allowing larger inner diameters to the cones, which allow the use of offset stems.This article aims to review the senior author's experience in managing bone loss in the revision TKA setting.

Revision for adverse local tissue reaction following metal-on-polyethylene total hip arthroplasty is associated with a high risk of early major complications.

Fretting and corrosion at the modular head/neck junction, known as trunnionosis, in total hip arthroplasty (THA) is a cause of adverse reaction to metal debris (ARMD). We describe the outcome of revision of metal-on-polyethylene (MoP) THA for ARMD due to trunnionosis with emphasis on the risk of major complications. A total of 36 patients with a MoP THA who underwent revision for ARMD due to trunnionosis were identified. Three were excluded as their revision had been to another metal head. The remaining 33 were revised to a ceramic head with a titanium sleeve. We describe the presentation, revision findings, and risk of complications in these patients. The patients presented with pain, swelling, stiffness, or instability and an inflammatory mass was confirmed radiologically. Macroscopic material deposition on the trunnion was seen in all patients, associated with ARMD. Following revision, six (18.2%) dislocated, requiring further revision in four. Three (9.1%) developed a deep infection and six (18.2%) had significant persistent pain without an obvious cause. One developed a femoral artery thrombosis after excision of an iliofemoral pseudotumor, requiring a thrombectomy. The risk of serious complications following revision MoP THA for ARMD associated with trunnionosis is high. In the presence of extensive tissue damage, a constrained liner or dual mobility construct is recommended in these patients. Cite this article: Bone Joint J 2018;100-B:720-4.

A Survey of the Prevalence of and Techniques to Prevent Trunnionosis.

Trunnionosis of total hip arthroplasty (THA) components has been an increasingly reported complication. Consensus is lacking regarding preventive practices and the overall incidence of trunnionosis. In this study, fellowship-trained adult reconstruction orthopedic surgeons were surveyed to identify expert opinions. A 25-question, web-based survey regarding trunnionosis incidence, prevention, and biomaterials was sent to 345 fellowship-trained adult reconstruction orthopedic surgeons in North America. The survey yielded 151 (43.8%) responses from surgeons with a mean of 11.97±9.49 years of experience. These surgeons believe that the material composite of the head-neck junction is the most important contributor to trunnionosis. They often choose a ceramic head with a metal alloy stem to reduce trunnionosis. They more commonly impact the femoral head 3 times than once. Fifty-one percent believe that trunnionosis leads to THA failure for between 0% and 2% of all THA revisions, whereas 48.3% believe that the failure rate is greater than 2%. More than half (53.6%) of these surgeons recommend a revision THA if a patient's serum cobalt level is greater than 10 µg/L, regardless of symptom presence. The incidence of trunnionosis appears to be increasing due to changes in implants and/or an increased awareness of the problem, with 48.3% of these surgeons believing that trunnionosis is the primary cause of THA failure for more than 1 in 50 patients. Some suggested preventive measures include cleaning and drying the trunnion, using ceramic femoral heads, matching THA components, and adding titanium sleeves on well-fixed stems that are retained during revision surgery. [Orthopedics. 2018; 41(4):e557-e562.].

Large-aperture alumina ceramics beam pipes with titanium bellows for the rapid cycling synchrotron at Japan Proton Accelerator Research Complex

The 3-GeV rapid-cycling synchrotron at the Japan Proton Accelerator Research Complex aims to generate proton beams whose power output is among the highest in the world, reaching an extraction beam power of 1 MW. Beam pipes fabricated using alumina ceramics are used to prevent the formation of eddy currents caused by the rapid magnetic field changes. The residual radioactive dose is higher in the beam-injection area than in other areas. In this area, ceramics beam pipes in a quadrupole magnet and a horizontal bump magnet are directly connected without bellows because of space limitations. Improvement of the maintainability of such areas is the first priority for minimizing the radiation exposure of maintenance workers. The ceramics beam pipe in the quadrupole magnet was custom designed to have bellows on both ends. The shapes of the ceramics end unit ducts and titanium sleeves of the pipe was revised to allow a 30-mm long space for inserting the bellows. The ceramics unit ducts and titanium sleeves with un...

Update on Microinvasive Glaucoma Surgery.

Update on Microinvasive Glaucoma Surgery.