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Sample records for hip spacer implantation

  1. Titanium-copper-nitride coated spacers for two-stage revision of infected total hip endoprostheses

    PubMed Central

    Ellenrieder, Martin; Haenle, Maximilian; Lenz, Robert; Bader, Rainer; Mittelmeier, Wolfram

    2011-01-01

    Within the first two years after total hip arthroplasty implant-associated infection has become the second most common reason for a revision surgery. Two-stage implant exchange is frequently conducted using temporary spacers made of antibiotic-loaded cement in order to prevent a bacterial colonization on the spacer. Avoiding several disadvantages of cement spacers, a conventional hemi-endoprosthesis was equipped with a copper-containing implant coating for inhibition of bacterial biofilms. In the present paper details of this novel treatment concept are presented including a case report. PMID:22242097

  2. Hip Resurfacing Implants.

    PubMed

    Cadossi, Matteo; Tedesco, Giuseppe; Sambri, Andrea; Mazzotti, Antonio; Giannini, Sandro

    2015-08-01

    EDUCATIONAL OBJECTIVES As a result of reading this article, physicians should be able to: 1. Describe the advantages of hip resurfacing. 2. Describe the disadvantages of hip resurfacing. 3. Identify the population in which hip resurfacing is most often indicated. 4. Demonstrate how to properly postoperatively manage patients with metal-on-metal prostheses. Hip resurfacing offers a suitable solution for young patients affected by hip disease who have high function demands and good bone quality. Bone stock preservation, restoration of the normal proximal femur anatomy, the lack of stress shielding, and the possibility of resuming sporting activity are proven advantages of hip resurfacing. However, there are some disadvantages, such as fracture of the femoral neck, onset of neck narrowing, and possible complications due to the metal-on-metal bearings, including pseudotumors, peri-implant osteolysis, and chronic elevation of metal ions in serum levels. Recent data suggest that the ideal candidate for hip resurfacing is an active male, younger than 65 years, with primary or posttraumatic osteoarthritis, and with a femoral head diameter larger than 50 to 54 mm. Based on these selection criteria, the literature reports implant survival to be similar to that of total hip arthroplasty. The current authors' experience confirms a low failure rate and excellent functional outcomes, with metal ion serum levels becoming stable over time in well-functioning implants. Proper surgical technique, correct patient selection, and the right choice of a well-established prosthetic model are essential elements for the long-term success of these implants. PMID:26270748

  3. Burnishing Techniques Strengthen Hip Implants

    NASA Technical Reports Server (NTRS)

    2010-01-01

    In the late 1990s, Lambda Research Inc., of Cincinnati, Ohio, received Small Business Innovation Research (SBIR) awards from Glenn Research Center to demonstrate low plasticity burnishing (LPB) on metal engine components. By producing a thermally stable deep layer of compressive residual stress, LPB significantly strengthened turbine alloys. After Lambda patented the process, the Federal Aviation Administration accepted LPB for repair and alteration of commercial aircraft components, the U.S. Department of Energy found LPB suitable for treating nuclear waste containers at Yucca Mountain. Data from the U.S. Food and Drug Administration confirmed LPB to completely eliminate the occurrence of fretting fatigue failures in modular hip implants.

  4. A Hip Implant Energy Harvester

    NASA Astrophysics Data System (ADS)

    Pancharoen, K.; Zhu, D.; Beeby, S. P.

    2014-11-01

    This paper presents a kinetic energy harvester designed to be embedded in a hip implant which aims to operate at a low frequency associated with body motion of patients. The prototype is designed based on the constrained volume available in a hip prosthesis and the challenge is to harvest energy from low frequency movements (< 1 Hz) which is an average frequency during free walking of a patient. The concept of magnetic-force-driven energy harvesting is applied to this prototype considering the hip movements during routine activities of patients. The magnetic field within the harvester was simulated using COMSOL. The simulated resonant frequency was around 30 Hz and the voltage induced in a coil was predicted to be 47.8 mV. A prototype of the energy harvester was fabricated and tested. A maximum open circuit voltage of 39.43 mV was obtained and the resonant frequency of 28 Hz was observed. Moreover, the power output of 0.96 μW was achieved with an optimum resistive load of 250Ω.

  5. Hip Implant Modified To Increase Probability Of Retention

    NASA Technical Reports Server (NTRS)

    Canabal, Francisco, III

    1995-01-01

    Modification in design of hip implant proposed to increase likelihood of retention of implant in femur after hip-repair surgery. Decreases likelihood of patient distress and expense associated with repetition of surgery after failed implant procedure. Intended to provide more favorable flow of cement used to bind implant in proximal extreme end of femur, reducing structural flaws causing early failure of implant/femur joint.

  6. Hip and knee arthroplasty implants contraindicated in obesity.

    PubMed

    Craik, J D; Bircher, M D; Rickman, M

    2016-05-01

    Introduction High patient weight is a risk factor for mechanical implant failure and some manufacturers list obesity as a contraindication for implant use. We reviewed data from the 2012-2013 UK National Joint Registry to determine whether surgical practice reflects these manufacturer recommendations. Methods The product literature for the most commonly used hip and knee implants was reviewed for recommendations against use in obese patients (body mass index [BMI] ≥ 30kg/m(2)). The total number of obese patients undergoing hip and knee arthroplasty was calculated, as was the proportion receiving implants against manufacturer recommendations. Results Out of 200,054 patient records, 147,691 (74%) had a recorded BMI. The mean BMI for patients undergoing primary total hip arthroplasty was 29kg/m(2), compared with 31kg/m(2) for total knee arthroplasty. Of the 25 components reviewed, 5 listed obesity as a contraindication or recommended against implant use in obese patients. A total of 10,745 patients (16% of all obese patients) received implants against manufacturer recommendations. Conclusions A high proportion of patients are receiving implants against manufacturer recommendations. However, there are limitations to using BMI for stratifying risk of implant fatigue failure and manufacturers should therefore provide more detailed guidelines on size specific implant load limits to facilitate surgical decisions. PMID:27023636

  7. [Change of offset after implantation of hip alloarthroplasties].

    PubMed

    Jerosch, J; Funken, S

    2004-06-01

    The purpose of the present study was to evaluate the change of the offset after implantation of hip alloarthroplasties. In an experimental study the X-ray templates of 90 different implants (594 different sizes) were digitized (cup and stem) and virtually implanted in the hip joint of 50 consecutive patients who were on the waiting list for hip replacement. Implantation was performed on AP X-rays paying heed to the fit of the shaft and adequate leg length. In total 4500 implantations were performed. After virtual implantation the change of the offset was calculated. There was a wide variance in the ability to fit the implants to the individual patient. For some patients it seems to be extremely difficult to adapt the implant without changing the offset. Some implant designs were only suitable for 2 patients while other designs were suitable for 40 patients (mean: 17). The average change of the offset was 0.27 cm. Considering only the cases in which a change occurs this value increases up to 0.56 cm.For the individual patient the average number of implants that were suitable was 30 (range: 1-67) of a total of 90 designs. Here the average change of the offset was 0.4 cm (-1.04 -- +1.54 cm). Considering only the cases in which a change occurs this value increases up to 0.64 cm. In the majority of the cases the presently available implants do not allow anatomic reconstruction of the individual offset. PMID:15197454

  8. Metallographic evaluation of hip joint implants wear and electrochemical implants potential.

    PubMed

    Kmieć, Krzysztof; Sibinski, Marcin; Synder, Marek; Drobniewski, Marek; Kozłowski, Piotr

    2014-12-01

    We performed metallographic evaluations of implants, removed during revision hip arthroplasty. The implants were evaluated for electrochemical potentials and the presence of wear products on the implants surface. A total of 50 patients (50 hips) underwent revision hip arthroplasty during the years 2007-2009 for aseptic loosening. The mean follow-up from primary hip replacement to revision was 10.1 years (from six months to 17 years). All hip joint implants removed during the revision arthroplasty were submitted to metallographic analysis and all heads were submitted to analysis under a scanning microscope. All polyethylene (PE) cups and inserts showed numerous features of wear (friction wear, plastic deformation and creeping, fatigue wear and degradation), six PE cups were broken. In six ceramic cups, only friction wear features were found; one of them was mechanically broken. In all heads articulating on PE not one had any mechanical damage. Heads of ceramic implants in ceramic-ceramic articulation undergo abrasive wear. None of the studied stems (cemented or uncemented) revealed any features of wear. Areas of titanium crystals (formed by electrolytic sedimentation of metals) were macroscopically identified on the sliding surface of six heads that was confirmed by chemical composition and scanning microscope.In the course of prosthesis use, wear products are produced and transferred onto the sliding surfaces of implant heads and cups via ways other than purely mechanical contact. It has been confirmed that metals used for implant construction, make galvanic cells with different electrochemical potentials. PMID:25362874

  9. Muscle atrophy and metal-on-metal hip implants

    PubMed Central

    Berber, Reshid; Khoo, Michael; Cook, Erica; Guppy, Andrew; Hua, Jia; Miles, Jonathan; Carrington, Richard; Skinner, John; Hart, Alister

    2015-01-01

    Background and purpose Muscle atrophy is seen in patients with metal-on-metal (MOM) hip implants, probably because of inflammatory destruction of the musculo-tendon junction. However, like pseudotumors, it is unclear when atrophy occurs and whether it progresses with time. Our objective was to determine whether muscle atrophy associated with MOM hip implants progresses with time. Patients and methods We retrospectively reviewed 74 hips in 56 patients (32 of them women) using serial MRI. Median age was 59 (23–83) years. The median time post-implantation was 83 (35–142) months, and the median interval between scans was 11 months. Hip muscles were scored using the Pfirrmann system. The mean scores for muscle atrophy were compared between the first and second MRI scans. Blood cobalt and chromium concentrations were determined. Results The median blood cobalt was 6.84 (0.24–90) ppb and median chromium level was 4.42 (0.20–45) ppb. The median Oxford hip score was 34 (5–48). The change in the gluteus minimus mean atrophy score between first and second MRI was 0.12 (p = 0.002). Mean change in the gluteus medius posterior portion (unaffected by surgical approach) was 0.08 (p = 0.01) and mean change in the inferior portion was 0.10 (p = 0.05). Mean pseudotumor grade increased by 0.18 (p = 0.02). Interpretation Worsening muscle atrophy and worsening pseudotumor grade occur over a 1-year period in a substantial proportion of patients with MOM hip implants. Serial MRI helps to identify those patients who are at risk of developing worsening soft-tissue pathology. These patients should be considered for revision surgery before irreversible muscle destruction occurs. PMID:25588091

  10. Optimal design of composite hip implants using NASA technology

    NASA Technical Reports Server (NTRS)

    Blake, T. A.; Saravanos, D. A.; Davy, D. T.; Waters, S. A.; Hopkins, D. A.

    1993-01-01

    Using an adaptation of NASA software, we have investigated the use of numerical optimization techniques for the shape and material optimization of fiber composite hip implants. The original NASA inhouse codes, were originally developed for the optimization of aerospace structures. The adapted code, which was called OPORIM, couples numerical optimization algorithms with finite element analysis and composite laminate theory to perform design optimization using both shape and material design variables. The external and internal geometry of the implant and the surrounding bone is described with quintic spline curves. This geometric representation is then used to create an equivalent 2-D finite element model of the structure. Using laminate theory and the 3-D geometric information, equivalent stiffnesses are generated for each element of the 2-D finite element model, so that the 3-D stiffness of the structure can be approximated. The geometric information to construct the model of the femur was obtained from a CT scan. A variety of test cases were examined, incorporating several implant constructions and design variable sets. Typically the code was able to produce optimized shape and/or material parameters which substantially reduced stress concentrations in the bone adjacent of the implant. The results indicate that this technology can provide meaningful insight into the design of fiber composite hip implants.

  11. Management of periprosthetic joint infection after total hip arthroplasty using a custom made articulating spacer (CUMARS); the Exeter experience.

    PubMed

    Tsung, Jason D; Rohrsheim, James A L; Whitehouse, Sarah L; Wilson, Matthew J; Howell, Jonathan R

    2014-09-01

    Periprosthetic joint infection (PJI) after THA is a major complication with an incidence of 1%-3%. We report our experiences with a technique using a custom-made articulating spacer (CUMARS) at the first of two-stage treatment for PJI. This technique uses widely available all-polyethylene acetabular components and the Exeter Universal stem, fixed using antibiotic loaded acrylic cement. Seventy-six hips were treated for PJI using this technique. Performed as the first of a two-stage procedure, good functional results were commonly seen, leading to postponing second stage indefinitely with retention of the CUMARS prosthesis in 34 patients. The CUMARS technique presents an alternative to conventional spacers, using readily available components that are well tolerated, allowing weight bearing and mobility, and achieving comparable eradication rates. PMID:24851790

  12. [The hard lesson of metal-on-metal hip implants].

    PubMed

    Verhaar, J A N Jan

    2012-01-01

    Metal-on-metal hip implants with a large metal head (≥ 36 mm) have shown periprosthetic adverse soft tissue reactions and high blood concentrations of metal ions in patients. This has raised concern that exposure to metal ions may induce complications and could increase the risk of cancer. In view of the present level of uncertainty and for reasons of patient safety, the Dutch Orthopaedic Association (NOV) has advised its members to suspend utilisation of all metal-on-metal hip implants with a large head (≥ 36 mm) until the safety and long-term effectiveness have been established. All patients with these implants will be invited for an annual check-up according to a set protocol. This outpatient examination will also include assessment of cobalt ion levels and X-ray diagnostics. Based on the blood concentration of cobalt, the clinical status and the X-ray, the patient will be advised to undergo a revision procedure of the implant. PMID:23075779

  13. Iodine-Supported Hip Implants: Short Term Clinical Results

    PubMed Central

    Kabata, Tamon; Maeda, Toru; Kajino, Yoshitomo; Hasegawa, Kazuhiro; Inoue, Daisuke; Yamamoto, Takashi; Takagi, Tomoharu; Ohmori, Takaaki; Tsuchiya, Hiroyuki

    2015-01-01

    We developed a new povidone iodine coating technology for titanium hip implants and performed a clinical trial to assess its usefulness in suppressing postoperative infection. Results indicate that iodine-supported titanium has favorable antibacterial activity, biocompatibility, and no cytotoxicity. Thirty joints in 28 patients were treated using iodine-supported implants. Fourteen joints were revision total hip arthroplasty (THA) after periprosthetic infection, 13 were primary THA for immunosuppressive conditions or pyogenic arthritis, and 3 were conversions from hemiarthroplasty to THA for immunosuppressive conditions. Two examinations were conducted sequentially until final follow-up: white blood cell (WBC) and C-reactive protein (CRP) were measured pre- and postoperatively and thyroid hormone levels in the blood were examined. The mean follow-up period was 33 months (14–78). There were no signs of infection in any patient at the last follow-up. WBC and CRP levels returned to normal within several weeks. No abnormalities of thyroid gland function were detected. Loosening of the implants did not occur in any patient. Excellent bone ingrowth and ongrowth were found around prostheses. No cytotoxicity or adverse effects were detected. These results suggest that iodine-supported THA implants can be highly effective in preventing and treating postoperative infections. PMID:26583103

  14. Antibiotic Spacer Arthroplasty for Revision MTP Arthrodesis: A Novel Means to Build the Implant: A Case Report

    PubMed Central

    Bitterman, Adam; Patel, Milap; Gurtowski, James P

    2016-01-01

    Metatarsophalangeal (MTP) joint osteoarthritis (OA), also known as hallux rigidus (HR), is the most common degenerative arthropathy of the foot and is often the result of trauma. There are multiple methods of addressing the patient’s pain and limited function. Arthrodesis is the gold standard to manage severe MTP arthritis with a highly significant union rate. With various techniques of arthrodesis available, ranging from cannulated screw fixation, Kirschner wires, as well as plate and screw fixation, the orthopedic surgeon has multiple modalities to address this ailment; however, when these fail due to infection, the armament is limited. Through the idea of articulating antibiotic spacers in other regions of the body such as the knee and hip, we present a novel technique to the creation of an antibiotic spacer in the setting of a failed infected MTP arthrodesis.  PMID:27114892

  15. The lubrication performance of the ceramic-on-ceramic hip implant under starved conditions

    PubMed Central

    Meng, Qingen; Wang, Jing; Yang, Peiran; Jin, Zhongmin; Fisher, John

    2015-01-01

    Lubrication plays an important role in the clinical performance of the ceramic-on-ceramic (CoC) hip implant in terms of reducing wear and avoiding squeaking. All the previous lubrication analyses of CoC hip implants assumed that synovial fluid was sufficiently supplied to the contact area. The aim of this study was to investigate the lubrication performance of the CoC hip implant under starved conditions. A starved lubrication model was presented for the CoC hip implant. The model was solved using multi-grid techniques. Results showed that the fluid film thickness of the CoC hip implant was affected by fluid supply conditions: with the increase in the supplied fluid layer, the lubrication film thickness approached to that of the fully blooded solution; when the available fluid layer reduced to some level, the fluid film thickness considerably decreased with the supplying condition. The above finding provides new insights into the lubrication performance of hip implants. PMID:26114217

  16. Design optimization of skeletal hip implant cross-sections using finite-element analysis.

    PubMed

    Beulah, Pearline; Sivarasu, Sudesh; Mathew, Lazar

    2009-01-01

    The major causes for revision surgery after total hip arthroplasty are aseptic loosening, dislocation, wear, design factors, stress shielding on the bone, and mechanical and biological factors. A material with toughness and high wear properties is essential for a good hip implant because these implants fail due to design. Stress shielding is found to be the major cause for the failure of hip implants, and can lead to the implant needing to be replaced or revised, which is painful for the patient and costly for the health care industry. The hip stem designs developed by various manufacturers are solid stems with indentations; stems with collars; collarless, tapered stems; and teardrop-shaped, polished stems without indentations. They are found to have a greater rigidity, and therefore they transfer less load proximally, which results in high proximal stress shielding of the proximal femur. A stem of low stiffness alone would not suffice in achieving a reduced or optimal stress shielding. The existing design proposals to minimize the effect of stress shielding are focused on the use of lightweight materials, composite materials, circular and longitudinal hole patterns, and different hollow-bore depths. A skeletal hip implant with varying cross-sections was designed and finite-element analysis was performed. The skeletal hip implant with a hexagonal cross-section was optimized based on the mass of the implant and the load-bearing capacity. This lightweight, novel design ameliorates implant fixation, minimizes stress shielding, enhances the longevity of the implant, and offers better mobility to the patient. PMID:21083533

  17. Finding the right hip implant for patient and surgeon: the Dutch strategy--empowering patients.

    PubMed

    Poolman, Rudolf W; Verhaar, Jan A N; Schreurs, B Willem; Bom, L Paul A; Nelissen, Rob G H H; Koot, Henk W J; Goosen, Jon H M; Verheyen, Cees C P M

    2015-01-01

    We describe the implementation process of hip prostheses selection in the Netherlands. The recent problems with large head metal-on-metal hip prostheses resulted in substantial damage to the surgeons' credibility and reputation in the media. This led to a true sense of urgency among orthopaedic surgeons to increase their activities to secure patient safety. The board of the Dutch Orthopaedic Association (NOV) in the Netherlands established a Dutch Hip Task Force (DHTF) with the explicit assignment of formulating criteria to classify the quality of total hip implants on the Dutch market based on survivorship. The aim was to offer unequivocal information enabling a balanced choice of total hip prosthesis. The ultimate goal of the NOV is that all implanted total hip prostheses implanted in the Netherlands are based on reliable clinical evidence. The DHTF decided to adapt the principles of the National Institute for Health and Care Excellence (NICE, UK) (www.nice.org.uk). The taskforce uses data from the registries as well as the Orthopaedic Data Evaluation Panel (ODEP). If the ODEP guidelines had been chosen as standard alone, one quarter of our listed hip components would not have been included. In our view this underlines the strength in the Dutch approach where high quality registry data and ODEP ratings are complementary and result in a list of reliable hip prostheses. Most importantly we offer patients insights into the known quality of the implants by sharing the results of our implant review. This will facilitate shared decision making by empowering patients in their knowledge on available hip arthroplasties. PMID:25633758

  18. High-tech hip implant for wireless temperature measurements in vivo.

    PubMed

    Bergmann, Georg; Graichen, Friedmar; Dymke, Jörn; Rohlmann, Antonius; Duda, Georg N; Damm, Philipp

    2012-01-01

    When walking long distances, hip prostheses heat up due to friction. The influence of articulating materials and lubricating properties of synovia on the final temperatures, as well as any potential biological consequences, are unknown. Such knowledge is essential for optimizing implant materials, identifying patients who are possibly at risk of implant loosening, and proving the concepts of current joint simulators. An instrumented hip implant with telemetric data transfer was developed to measure the implant temperatures in vivo. A clinical study with 100 patients is planned to measure the implant temperatures for different combinations of head and cup materials during walking. This study will answer the question of whether patients with synovia with poor lubricating properties may be at risk for thermally induced bone necrosis and subsequent implant failure. The study will also deliver the different friction properties of various implant materials and prove the significance of wear simulator tests. A clinically successful titanium hip endoprosthesis was modified to house the electronics inside its hollow neck. The electronics are powered by an external induction coil fixed around the joint. A temperature sensor inside the implant triggers a timer circuit, which produces an inductive pulse train with temperature-dependent intervals. This signal is detected by a giant magnetoresistive sensor fixed near the external energy coil. The implant temperature is measured with an accuracy of 0.1°C in a range between 20°C and 58°C and at a sampling rate of 2-10 Hz. This rate could be considerably increased for measuring other data, such as implant strain or vibration. The employed technique of transmitting data from inside of a closed titanium implant by low frequency magnetic pulses eliminates the need to use an electrical feedthrough and an antenna outside of the implant. It enables the design of mechanically safe and simple instrumented implants. PMID:22927973

  19. High-Tech Hip Implant for Wireless Temperature Measurements In Vivo

    PubMed Central

    Bergmann, Georg; Graichen, Friedmar; Dymke, Jörn; Rohlmann, Antonius; Duda, Georg N.; Damm, Philipp

    2012-01-01

    When walking long distances, hip prostheses heat up due to friction. The influence of articulating materials and lubricating properties of synovia on the final temperatures, as well as any potential biological consequences, are unknown. Such knowledge is essential for optimizing implant materials, identifying patients who are possibly at risk of implant loosening, and proving the concepts of current joint simulators. An instrumented hip implant with telemetric data transfer was developed to measure the implant temperatures in vivo. A clinical study with 100 patients is planned to measure the implant temperatures for different combinations of head and cup materials during walking. This study will answer the question of whether patients with synovia with poor lubricating properties may be at risk for thermally induced bone necrosis and subsequent implant failure. The study will also deliver the different friction properties of various implant materials and prove the significance of wear simulator tests. A clinically successful titanium hip endoprosthesis was modified to house the electronics inside its hollow neck. The electronics are powered by an external induction coil fixed around the joint. A temperature sensor inside the implant triggers a timer circuit, which produces an inductive pulse train with temperature-dependent intervals. This signal is detected by a giant magnetoresistive sensor fixed near the external energy coil. The implant temperature is measured with an accuracy of 0.1°C in a range between 20°C and 58°C and at a sampling rate of 2–10 Hz. This rate could be considerably increased for measuring other data, such as implant strain or vibration. The employed technique of transmitting data from inside of a closed titanium implant by low frequency magnetic pulses eliminates the need to use an electrical feedthrough and an antenna outside of the implant. It enables the design of mechanically safe and simple instrumented implants. PMID:22927973

  20. Influence of PEEK Coating on Hip Implant Stress Shielding: A Finite Element Analysis

    PubMed Central

    Anguiano-Sanchez, Jesica; Martinez-Romero, Oscar; Siller, Hector R.; Diaz-Elizondo, Jose A.; Flores-Villalba, Eduardo

    2016-01-01

    Stress shielding is a well-known failure factor in hip implants. This work proposes a design concept for hip implants, using a combination of metallic stem with a polymer coating (polyether ether ketone (PEEK)). The proposed design concept is simulated using titanium alloy stems and PEEK coatings with thicknesses varying from 100 to 400 μm. The Finite Element analysis of the cancellous bone surrounding the implant shows promising results. The effective von Mises stress increases between 81 and 92% for the complete volume of cancellous bone. When focusing on the proximal zone of the implant, the increased stress transmission to the cancellous bone reaches between 47 and 60%. This increment in load transferred to the bone can influence mineral bone loss due to stress shielding, minimizing such effect, and thus prolonging implant lifespan. PMID:27051460

  1. Investigation of Wear and Corrosion of a High-Carbon Stellite Alloy for Hip Implants

    NASA Astrophysics Data System (ADS)

    Hu, P. S.; Liu, R.; Liu, J.; McRae, G.

    2014-04-01

    Low-carbon Stellite 21 has been used as hip implant material for a number of decades; however, its limited metal-on-metal bearing has resulted in loosening between the femoral head and the acetabular cup of hip implants. In order to improve the metal-on-metal bearing, it is proposed that a high-carbon alloy, Stellite 720, surface coating be applied on Stellite 21 hip implants to improve mechanical and tribological performance. For this coating to be practical, it must also meet the requirements of corrosion resistance for orthopedic implant materials. In this research, Stellite 720 is investigated with pin-on-disk wear tests, and electrochemical and immersion corrosion tests in simulated human body fluid (Hank's solution; pH 7.4 at temperature of 37°C). The experimental results demonstrate that Stellite 720 exhibits much better wear resistance than Stellite 21, and has the potential for better corrosion resistance as well. The applicability of coating Stellite 21 hip implants with Stellite 720 is discussed.

  2. Sheep Hip Arthroplasty Model of Failed Implant Osseointegration

    PubMed Central

    Jakobsen, Thomas; Kold, Søren; Baas, Jørgen; Søballe, Kjeld; Rahbek, Ole

    2015-01-01

    Early secure stability of an implant is important for long-term survival. We examined whether micromotion of implants consistently would induce bone resorption and formation of a fibrous membrane and thereby prevent osseointegration. One micromotion implant was inserted into one of the medial femoral condyles in ten sheep. The micromotion device consists of an anchor bearing a PMMA implant and a PE plug. During each gait cycle the PE plug will make the PMMA implant axially piston 0.5 mm. After 12 weeks of observation the bone specimens were harvested and a post-mortem control implant was inserted into the contra-lateral medial femoral condyle. Histomorphometrical evaluation showed that the surface on the implant observed for 12 weeks was covered by fibrous tissue. The control implants were covered by lamellar bone. No difference was found with respect to the volume fraction of lamellar bone in a 1 mm zone around the implants. This study indicates that implant micromotion is sufficient to induce bone resorption and formation of a fibrous membrane. PMID:26664497

  3. Management of metal-on-metal hip implant patients: Who, when and how to revise?

    PubMed

    Berber, Reshid; Skinner, John A; Hart, Alister J

    2016-05-18

    The debate on how best to manage patients with metal-on-metal (MOM) hip implants continues. With over 1 million patients affected worldwide, the impact is far reaching. The majority of the aggressive failures of MOM hip implants have been dealt with by revision hip surgery, leaving patients with a much more indolent pattern of failure of devices that have been in situ for more than 10 years. The longer-term outcome for such patients remains unknown, and much debate exists on how best to manage these patients. Regulatory guidance is available but remains open to interpretation due to the lack of current evidence and long-term studies. Metal ion thresholds for concern have been suggested at 7 ppb for hip resurfacing arthroplasty and below this level for large diameter total hip arthroplasties. Soft tissue changes including pseudotumours and muscle atrophy have been shown to progress, but this is not consistent. New advanced imaging techniques are helping to diagnose complications with metal hips and the reasons for failure, however these are not widely available. This has led to some centres to tackle difficult cases through multidisciplinary collaboration, for both surgical management decisions and also follow-up decisions. We summarise current evidence and consider who is at risk, when revision should be undertaken and how patients should be managed. PMID:27190754

  4. Management of metal-on-metal hip implant patients: Who, when and how to revise?

    PubMed Central

    Berber, Reshid; Skinner, John A; Hart, Alister J

    2016-01-01

    The debate on how best to manage patients with metal-on-metal (MOM) hip implants continues. With over 1 million patients affected worldwide, the impact is far reaching. The majority of the aggressive failures of MOM hip implants have been dealt with by revision hip surgery, leaving patients with a much more indolent pattern of failure of devices that have been in situ for more than 10 years. The longer-term outcome for such patients remains unknown, and much debate exists on how best to manage these patients. Regulatory guidance is available but remains open to interpretation due to the lack of current evidence and long-term studies. Metal ion thresholds for concern have been suggested at 7 ppb for hip resurfacing arthroplasty and below this level for large diameter total hip arthroplasties. Soft tissue changes including pseudotumours and muscle atrophy have been shown to progress, but this is not consistent. New advanced imaging techniques are helping to diagnose complications with metal hips and the reasons for failure, however these are not widely available. This has led to some centres to tackle difficult cases through multidisciplinary collaboration, for both surgical management decisions and also follow-up decisions. We summarise current evidence and consider who is at risk, when revision should be undertaken and how patients should be managed. PMID:27190754

  5. Is a Sliding Hip Screw or IM Nail the Preferred Implant for Intertrochanteric Fracture Fixation?

    PubMed Central

    Aros, Brian; Tosteson, Anna N. A.; Gottlieb, Daniel J.

    2008-01-01

    This study was performed to determine whether patients who sustain an intertrochanteric fracture have better outcomes when stabilized using a sliding hip screw or an intramedullary nail. A 20% sample of Part A and B entitled Medicare beneficiaries 65 years or older was used to generate a cohort of patients who sustained intertrochanteric femur fractures between 1999 and 2001. Two fracture implant groups, intramedullary nail and sliding hip screw, were identified using Current Procedural Terminology and International Classification of Diseases, 9th Revision codes. The cohort consisted of 43,659 patients. Patients treated with an intramedullary nail had higher rates of revision surgery during the first year than those treated with a sliding hip screw (7.2% intramedullary nail versus 5.5% sliding hip screw). Mortality rates at 30 days (14.2% intramedullary nail versus 15.8% sliding hip screw) and 1 year (30.7% intramedullary nail versus 32.5% sliding hip screw) were similar. Adjusted secondary outcome measures showed significant increases in the intramedullary nail group relative to the sliding hip screw group for index hospital length of stay, days of rehabilitation services in the first 6 months after discharge, and total expenditures for doctor and hospital services. Level of Evidence: Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence. PMID:18465180

  6. Implant failure in a proximal femoral fracture treated with dynamic hip screw fixation

    PubMed Central

    Dabis, John; Abdul-Jabar, Hani B.; Dabis, Hosam

    2015-01-01

    Dynamic hip screw fixation is a common orthopaedic procedure and to date, still can cause difficulties to the senior trauma surgeon. We present a case where an extra-capsular fracture of the proximal femur was managed with a dynamic hip screw (DHS) fixation. She proceeded to the operating theatre, where the fracture was stabilized with a 75-mm DHS and short-barrelled plate. The implant position was checked with intraoperative screening and the position accepted. Following attempted mobilization at 11 days post-operatively, the patient developed a recurrence of her preoperative pain. X-ray showed that the implant screw had separated from the barrel. Later scrutiny of the intraoperative screening films revealed that the barrel and screw were not engaged at the time of surgery. Intraoperative screening films should be carefully checked to ensure congruity of implant components. PMID:26136561

  7. Implant failure in a proximal femoral fracture treated with dynamic hip screw fixation.

    PubMed

    Dabis, John; Abdul-Jabar, Hani B; Dabis, Hosam

    2015-01-01

    Dynamic hip screw fixation is a common orthopaedic procedure and to date, still can cause difficulties to the senior trauma surgeon. We present a case where an extra-capsular fracture of the proximal femur was managed with a dynamic hip screw (DHS) fixation. She proceeded to the operating theatre, where the fracture was stabilized with a 75-mm DHS and short-barrelled plate. The implant position was checked with intraoperative screening and the position accepted. Following attempted mobilization at 11 days post-operatively, the patient developed a recurrence of her preoperative pain. X-ray showed that the implant screw had separated from the barrel. Later scrutiny of the intraoperative screening films revealed that the barrel and screw were not engaged at the time of surgery. Intraoperative screening films should be carefully checked to ensure congruity of implant components. PMID:26136561

  8. Precaution, governance and the failure of medical implants: the ASR((TM)) hip in the UK.

    PubMed

    Wienroth, Matthias; McCormack, Pauline; Joyce, Thomas J

    2014-01-01

    Hip implants have provided life-changing treatment, reducing pain and improving the mobility and independence of patients. Success has encouraged manufacturers to innovate and amend designs, engendering patient hopes in these devices. However, failures of medical implants do occur. The failure rate of the Articular Surface Replacement metal-on-metal hip system, implanted almost 100,000 times world-wide, has re-opened debate about appropriate and timely implant governance. As commercial interests, patient hopes, and devices' governance converge in a socio-technical crisis, we analyse the responses of relevant governance stakeholders in the United Kingdom between 2007 and 2014. We argue that there has been a systemic failure of the governance system entrusted with the safety of patients fitted with medical implants. Commercial considerations of medical implants and the status quo of medical implant governance have been given priority over patient safety despite the availability of significant failure data in an example of uncertainty about what constitutes appropriate precautionary action. PMID:26573983

  9. Lubrication and friction prediction in metal-on-metal hip implants

    NASA Astrophysics Data System (ADS)

    Wang, F. C.; Brockett, C.; Williams, S.; Udofia, I.; Fisher, J.; Jin, Z. M.

    2008-03-01

    A general methodology of mixed lubrication analysis and friction prediction for a conforming spherical bearing in hip implants was developed, with particular reference to a typical metal-on-metal hip replacement. Experimental measurement of frictional torque for a similar implant was carried out to validate the theoretical prediction. A ball-in-socket configuration was adopted to represent the articulation between the femoral head and the acetabular cup under cyclic operating conditions of representative load and motion. The mixed lubrication model presented in this study was first applied to identify the contact characteristics on the bearing surfaces, consisting of both fluid-film and boundary lubricated regions. The boundary lubricated contact was assumed to occur when the predicted fluid film thickness was less than a typical boundary protein layer absorbed on the bearing surfaces. Subsequently, the friction was predicted from the fluid-film lubricated region with viscous shearing due to both Couette and Poiseuille flows and the boundary protein layer contact region with a constant coefficient of friction. The predicted frictional torque of the typical metal-on-metal hip joint implant was compared with the experimental measurement conducted in a functional hip simulator and a reasonably good agreement was found. The mixed lubrication regime was found to be dominant for the conditions considered. Although the percentage of the boundary lubricated region was quite small, the corresponding contribution to friction was quite large and the resultant friction factor was quite high.

  10. Effect of friction and clearance on kinematics and contact mechanics of dual mobility hip implant.

    PubMed

    Gao, Yongchang; Chai, Wei; Wang, Ling; Wang, Manyi; Jin, Zhongmin

    2016-01-01

    The dual mobility hip implant has been introduced recently and increasingly used in total hip replacement to maintain the stability and reduce the risk of post-surgery dislocation. However, the kinematics and contact mechanisms of dual mobility hip implants have not been investigated in detail in the literature. Therefore, finite element method was adopted in this study to investigate dynamics and contact mechanics of a typical metal-on-polymer dual mobility hip implant under different friction coefficient ratios between the inner and the outer articulations and clearances/interferences between the ultra-high-molecular-weight polyethylene liner and the metal back shell. A critical ratio of friction coefficients between the two pairs of contact interfaces was found to mainly determine the rotating surfaces. Furthermore, an initial clearance between the liner and the back shell facilitated the rotation of the liner while an initial interference prevented such a motion at the outer articulating interface. In addition, the contact area and the sliding distance at the outer articulating surface were markedly greater than those at the inner cup-head interface, potentially leading to extensive wear at the outer surface of the liner. PMID:26586527

  11. Finite element analysis of sliding distance and contact mechanics of hip implant under dynamic walking conditions.

    PubMed

    Gao, Yongchang; Jin, Zhongmin; Wang, Ling; Wang, Manyi

    2015-06-01

    An explicit finite element method was developed to predict the dynamic behavior of the contact mechanics for a hip implant under normal walking conditions. Two key parameters of mesh sensitivity and time steps were examined to balance the accuracy and computational cost. Both the maximum contact pressure and accumulated sliding distance showed good agreement with those in the previous studies using the implicit finite element analysis and analytical methods. Therefore, the explicit finite element method could be used to predict the contact pressure and accumulated sliding distance for an artificial hip joint simultaneously in dynamic manner. PMID:25963387

  12. Trends in total hip arthroplasty implant utilization in the United States.

    PubMed

    Lehil, Mandeep S; Bozic, Kevin J

    2014-10-01

    Total hip arthroplasty (THA) implant usage has evolved as experience has been gained with newer implant designs. The purpose of this study was to characterize trends in THA implant usage between 2001 and 2012. The Orthopedic Research Network, which includes 174 hospitals and ~105,000 THA, was used to evaluate trends in fixation, bearings, acetabular cup and liner, and femoral head usage. In 2012, 93% of THAs were cementless; 56% of THA bearings were metal-HXLPE; and 35% were ceramic-HXLPE. 99% of acetabular cups were modular. 61% of femoral heads were metal, 39% were ceramic, 51% were 36mm, and 28% were 32mm. THA implant usage trends favor cementless fixation, metal-on-polyethylene or ceramic-on-polyethylene bearings, modular acetabular cups, and large diameter femoral heads. PMID:25062807

  13. Removal of trabecular metal osteonecrosis intervention implant and conversion to primary total hip arthroplasty.

    PubMed

    Owens, Joshua B; Ely, Erin E; Guilliani, Nathania M Figueroa; Suarez, Juan C; Patel, Preetesh D

    2012-06-01

    Core decompression and placement of the Trabecular Metal Osteonecrosis Intervention Implant have shown to be initially successful in treating early osteonecrosis. When treatment fails, however, patients often undergo primary total hip arthroplasty (THA) requiring removal of a previously inserted trabecular metal implant. We describe a technical tip for removal of a well-ingrown trabecular metal screw. A metal-cutting trephine placed over the screw allows for removal in an efficient manner while minimizing additional dissection and bone loss during conversion to THA. PMID:22425306

  14. The short stem GHEs in total hip replacement experience after 380 implantations

    PubMed Central

    Ghanem, Mohamed; Farag, M.; Schneider, P.; Hitzler, P.; Gulow, J.; Freiherr von Salis-Soglio, G

    2013-01-01

    Introduction: Standard straight stems have been recognized as a gold standard implant in the field of hip replacement surgery. However, lately uncemented bone-preserving short stems started to gain more and more popularity. This was reflected in the increasing variety of available models. Up till now, short and mid-term results are available. Patients and methods: In 2002, the cementless short stemmed GHEs was introduced. 380 patients were included in our study between 2002 and 2008. Only GHEs short stems were implanted. The clinical and radiological evaluations were performed in the Orthopaedic Department, Leipzig University Hospitals, on the average of 24 months (3 to 60 months) postoperatively. Results: 365 primary implantations and 15 revision implantations were carried out. Average age 60 years. Favourable clinical and radiological outcome was seen in 361/380 patients (95%). Postoperative complications were seen in 19/380 patients (5%): 8 fissures/fractures (2.1%), 5 infections (1.3%), 4 aseptic loosenings (1.1%), 2 dislocations (0.5%). Conclusions: Short stem implants, including our own experience with GHEs model, are satisfying and promising. They represent a valuable supplementation of the treatment modalities in hip replacement surgery. However, long term results are still awaited. PMID:26504707

  15. Optical measurement system for preparation and after-OP-check of a hip joint endoprothetic implantation

    NASA Astrophysics Data System (ADS)

    Maschke, R.; Lempe, B.; Taudt, Ch.; Rudek, F.; Baselt, T.; Basan, F.; Grunert, R.; Hartmann, P.

    2014-02-01

    With 332,000 operations carried out every year, the implantation of an artificial hip joint is one of the most common surgical operations performed in the US. According to prognosis which takes the demographical change into account, the number of these operations will increase in the coming years. One of the essential requirements is the perfect reconstruction of the biomechanical functions, especially the knowledge about the center of the hip rotation and the length of the leg. Based on this information it is possible to ensure the right position of the newly set leg during surgery. The aim of this work is to present and evaluate an optical measurement method in order to gather information about the center of the hip joint and the leg length. An appropriate laboratory setup has been designed and implemented in order to evaluate two different approaches: a structured light-method consisting of a DLP-Beamer or a laser source which projects defined patterns onto the patient and a marker-based system. Together with this both methods are combined with custom software to determine the hip joint center and the leg length with an accuracy of around +/- 0.2 inches. The clinical use of the tested approaches would give the surgeon the opportunity to reset the implant-parameters in the course of the surgery. In this way subsequent illnesses such as scoliotic pelvis can be prevented.

  16. Lessons learned from early clinical experience and results of 300 ASR hip resurfacing implantations.

    PubMed

    Siebel, T; Maubach, S; Morlock, M M

    2006-02-01

    Between August 2003 and April 2005, 300 ASR metal-on-metal resurfacing hip endoprostheses were implanted by the first author and a fellow surgeon. The mean age at surgery was 56.8 years (18-75.9 years) and mean body mass index was 27.6 kg/m2 (range, 19-41 kg/m2). The mean follow-up time was 202 days. The mean Harris hip score improved from 44 pre-operatively to 89 at 3 months post-operatively. In total, eight (2.7 per cent) cases [five neck fractures (1.66 per cent) and three cup revisions (1 per cent)] were revised. Two neck fractures occurred within a group of seven cases of femoral neck notching detected postoperatively; one neck fracture occurred out of two cases of incomplete seating of the femoral implant. A significantly higher (p < 0.001) failure rate was observed for patients who had undergone a previous osteosynthesis of the proximal femur (three revisions in a group of 15 patients). Revision cases had a significantly greater body mass index (p = 0.031). A learning curve was evident from the reduction in revisions from 5 in the first 100 surgical procedures to 2 in the next 100 and 1 in the last 100. These results show the importance of accurate surgical technique and careful patient selection for fourth-generation hip resurfacing implants, PMID:16669400

  17. Inflammatory response to therapeutic gold bead implantation in canine hip joint osteoarthritis.

    PubMed

    Lie, K-I; Jæger, G; Nordstoga, K; Moe, L

    2011-11-01

    Inflammatory changes associated with periarticular pure gold bead implants were studied in dogs involved in a clinical trial investigating motor dysfunction and chronic pain owing to hip joint dysplasia and osteoarthritis. Gold beads were percutaneously implanted via a needle into different locations surrounding the greater trochanter of the femur. Nine dogs with implants were necropsied. In all examined animals, characteristic histologic lesions were observed in the tissue surrounding the gold implants--namely, a fibrous capsule composed of concentric fibroblasts intermixed with a variable number of inflammatory cells and a paucicellular innermost layer of collagen with a few fibrocyte-like cells in empty lacunae. Lymphocytes dominated the inflammatory infiltrate, with rarely observed macrophages present in close proximity to the implant site. No giant cells were observed. Immunohistochemistry showed mixed populations of lymphocytes, both CD3 positive (T cells) and CD79a positive (B cells), which in some cases formed lymphoid follicles. Diffuse inflammatory changes were present to a minor extent in the perimysium and surrounding fascia. The inflammation observed in dogs is similar to that observed with gold implants in humans. It is possible that the clinically beneficial effect of gold beads for chronic osteoarthritis depends on sustained localized inflammation with localized release of soluble mediators. The encapsulation of the implant by a paucicellular and poorly vascularized fibrous capsule may help prevent an exaggerated inflammatory reaction by sequestering the gold bead from the surrounding tissue. PMID:20861497

  18. Good short-term outcome of primary total hip arthroplasty with cementless bioactive glass ceramic bottom-coated implants

    PubMed Central

    2012-01-01

    Background and purpose Cementless total hip arthroplasty is currently favored by many orthopedic surgeons. The design of the porous surface is critically important for long-term fixation. We examined the clinical and radiographic outcome of the cementless titanium hip implant with a bottom coating of apatite-wollastonite containing bioactive glass ceramic. Methods We retrospectively reviewed 109 hips (92 patients) that had undergone primary cementless total hip arthroplasty with bioactive glass ceramic bottom-coated implants. The mean follow-up period was 7 (3–9) years. Hip joint function was evaluated with the Merle d’Aubigné and Postel hip score, and radiographic changes were determined from anteroposterior radiographs. Results The mean hip score improved from 9.7 preoperatively to 17 at the final follow-up. The overall survival rate was 100% at 9 years, when radiographic loosening or revision for any reason was used as the endpoint. 3 stems in 2 patients subsided more than 3 mm vertically within 1 year after implantation. Radiographs of the interface of the stem and femur were all classified as bone ingrowth fixation. Conclusions The short-term results of this study show good outcome for cementless implants with a bottom coating of apatite-wollastonite containing bioactive glass ceramic. PMID:23043270

  19. If hip implant retrievals could speak, what would they tell us?

    PubMed

    Cuckler, J M

    2012-11-01

    Hip implant retrieval analysis is the most important source of insight into the performance of new materials and designs of hip arthroplasties. Even the most rigorous in vitro testing will not accurately simulate the behavior of implant materials and new designs of prosthetic arthroplasties. Retrieval analysis has revealed such factors as the effects of gamma-in-air sterilisation of polyethylene, fatigue failure mechanisms of polymethylmethacrylate bone cement, fretting corrosion of Morse taper junctions, third body wear effects of both hard-on-hard and hard-on-soft bearing couples, and the effects of impingement of components on the full spectrum of bearing surfaces, none of which was predicted by pre-implantation in vitro testing of these materials and combinations. The temporal sequence of the retrieval process is approximately six years from first implantation through retrieval analysis, laboratory investigation, and publication of results, and thus, in addition to rigorous clinical evaluation, represents the true development and insight cycle for new designs and materials. PMID:23118372

  20. Life expectancy of modular Ti6Al4V hip implants: influence of stress and environment.

    PubMed

    Chandra, A; Ryu, J J; Karra, P; Shrotriya, P; Tvergaard, V; Gaisser, M; Weik, T

    2011-11-01

    Stress dependent electrochemical dissolution is identified as one of the key mechanisms governing surface degradation in fretting and crevice corrosion of biomedical implants. The present study focuses on delineating the roles of mechanical stress and chemical conditions on the life expectancy of modular hip implants. First, material removal on a stressed surface of Ti6Al4V subjected to single asperity contact is investigated experimentally to identify the influence of contact load, in-plane stress and chemical environment on mean wear rates. A range of known stress levels are applied to the specimen while its surface is mechanically stimulated in different non-reactive to oxidizing aqueous environments. Evolution of surface degradation is monitored, and its mechanism is elucidated. This phase allows estimation of Preston Constant which is later used in the analysis. Second phase of the work is semi-analytical and computational, where, based on the estimated Preston constant and other material and process parameters, the scratch propensity (consisting of magnitude of scratch depth and their frequency per unit area) due to micro-motion in modular hip implants is estimated. The third phase views these scratches as initial notches and utilizes a mixed-mode fatigue crack propagation model to estimate the critical crack length for onset of instability. The number of loading cycles needed to reach this critical crack length is then labeled as the expected life of the implant under given mechanical and chemical conditions. Implications of different material and process conditions to life expectancy of orthopedic implants are discussed. It is observed that transverse micro-motion, compared to longitudinal micro-motion, plays a far more critical role in determining the implant life. Patient body weight, as well as proximity of the joint fluid to its iso-electric point play key roles in determining wear rates and associated life expectancies of modular hip implants. Sustained aeration of joint fluid, as well as proper tolerancing of mating surfaces, along with a proper choice of material microstructure may be utilized to extend implant life. PMID:22098898

  1. Revision total hip and knee arthroplasty implant identification: implications for use of Unique Device Identification 2012 AAHKS member survey results.

    PubMed

    Wilson, Natalia A; Jehn, Megan; York, Sally; Davis, Charles M

    2014-02-01

    FDA's Unique Device Identification (UDI) Rule will mandate manufacturers to assign unique identifiers to their marketed devices. UDI use is expected to improve implant documentation and identification. A 2012 American Association of Hip and Knee Surgeons membership survey explored revision total hip and knee arthroplasty implant identification processes. 87% of surgeons reported regularly using at least 3 methods to identify failed implants pre-operatively. Median surgeon identification time was 20 min; median staff time was 30 min. 10% of implants could not be identified pre-operatively. 2% could not be identified intra-operatively. UDI in TJA registry and UDI in EMR were indicated practices to best support implant identification and save time. FDA's UDI rule sets the foundation for UDI use in patient care settings as standard practice for implant documentation. PMID:23890830

  2. Prospective analysis of human leukocyte functional tests reveals metal sensitivity in patients with hip implant

    PubMed Central

    2013-01-01

    Background The aim of the study was to examine the reactivity of peripheral human leukocytes to various metal ions prior and following hip replacement in order to investigate implant-induced metal sensitivity. Methods Three patient groups were set up: (1) individuals without implants and no history of metal allergy (7 cases), (2) individuals without implants and known history of metal allergy (7 cases), and (3) patients undergoing cementless hip replacement (40 cases). Blood samples were taken in groups 1 and 2 at three different occasions; in group 3, prior and 3, 6, 12, 24, and 36 months after surgery. Peripheral leukocytes were separated and left either untreated or challenged with Ti, NiCl2, CoCl2, CrCl3, and phytohemagglutinin. Cell proliferation, cytokine release, and leukocyte migration inhibition assays were performed. Metal-induced reactivity was considered when all three assays showed significant change. Skin patch tests were also carried out. Results Both skin patch tests and leukocyte functional tests were negative in group 1, and both were positive in group 2. In group 3, after 6 months, 12% of the patients showed reactivity to the tested metals except for NiCl2. Following the 36-month period, 18% of group three became sensitive to metals (including all the earlier 12%). In contrast, patch tests were negative at each time point in group 3. Conclusions Orthopedic implant material may induce metal reactivity after implantation in a manner where susceptibility is yet to be elucidated. Leukocyte triple assay technique might be a useful tool to test implant material-related sensitivity. PMID:23680415

  3. A double mobility acetabular implant for primary hip arthroplasty in patients at high risk of dislocation

    PubMed Central

    Middleton, RG; Young, P; Uzoigwe, C; Barkham, B; Yusoff, S; Minhas, THA

    2014-01-01

    Introduction Dislocation following total hip replacement continues to be a problem for which no completely satisfactory solution has been found. Several methods have been proposed to reduce the incidence of hip dislocations with varying degrees of success, including elevated rim liners, constrained liners and large diameter bearings. We present our experience with the double mobility acetabular component in patients at high risk of instability. Methods This was a retrospective review of 65 primary total hip arthroplasties in 55 patients (15 men, 40 women), performed between October 2005 and November 2009. The majority (80%) of patients had at least two and 26% had at least three risk factors for instability. The mean age was 76 years (range: 44–92 years). The patients were followed up for a mean duration of 60 months (range: 36–85 months). Results Fourteen patients died and one was lost to follow-up, leaving fifty hips for final assessment. Until the final follow-up appointment, no patients had dislocation and none required revision surgery. The mean Oxford hip score improved from 45.0 to 26.5 (p<0.0001). The mean Merle d’Aubigné pain score improved from 1.4 to 4.9 (p<0.0001), the walking score from 2.3 to 3.1 (p<0.07) and the absolute hip function score from 5.4 to 10.8 (p<0.0001). There were no clinical or radiographic signs of loosening. Conclusions The double mobility acetabular component was successful at preventing dislocation during early to medium-term follow-up. However, as data are still lacking with regard to polyethylene wear rates at the additional bearing surface, it would be prudent to restrict the use of this implant to selected patients at high risk of instability. PMID:25350182

  4. Simulation of the mechanical behavior of a HIP implant. Implant fixed to bone by cementation under arbitrary load

    NASA Astrophysics Data System (ADS)

    Oldani, C. R.; Dominguez, A. A.

    2007-11-01

    In a previous work a finite elements model was constructed to simulate a fatigue assay according to the norm IRAM 9422-3. Three materials were studied, two of them are the most used in this type of implant (Stainless steel 3161 and alloy T16A14V) and the third was a new developed titanium alloy (Ti35Nb7Zr5Ta). Static loads were applied to the model according to the highest requirements of the norm and the stress - strain distribution were determined. In this study a simplified analysis of the material's fatigue was done according to the previous work. The best behavior of the titanium alloys vs. the stainless steel was evident. With the objective of studying the behavior of both: the implant and the femur bone, new finite elements models were realized, in which the presence of the bone was considered. Inside the bone, the femoral component of the implant was placed in a similar way of a cemented prosthesis in a total hip arthroplasty. The advantage of the titanium implant related to the stainless steel one, was very clear.

  5. Implant Optimisation for Primary Hip Replacement in Patients over 60 Years with Osteoarthritis: A Cohort Study of Clinical Outcomes and Implant Costs Using Data from England and Wales

    PubMed Central

    Jameson, Simon S.; Mason, James; Baker, Paul N.; Gregg, Paul J.; Deehan, David J.; Reed, Mike R.

    2015-01-01

    Background Hip replacement is one of the most commonly performed surgical procedures worldwide; hundreds of implant configurations provide options for femoral head size, joint surface material and fixation method with dramatically varying costs. Robust comparative evidence to inform the choice of implant is needed. This retrospective cohort study uses linked national databases from England and Wales to determine the optimal type of replacement for patients over 60 years undergoing hip replacement for osteoarthritis. Methods and Findings Implants included were the commonest brand from each of the four types of replacement (cemented, cementless, hybrid and resurfacing); the reference prosthesis was the cemented hip procedure. Patient reported outcome scores (PROMs), costs and risk of repeat (revision) surgery were examined. Multivariable analyses included analysis of covariance to assess improvement in PROMs (Oxford hip score, OHS, and EQ5D index) (9159 linked episodes) and competing risks modelling of implant survival (79,775 procedures). Cost of implants and ancillary equipment were obtained from National Health Service procurement data. Results EQ5D score improvements (at 6 months) were similar for all hip replacement types. In females, revision risk was significantly higher in cementless hip prostheses (hazard ratio, HR = 2.22, p<0.001), when compared to the reference hip. Although improvement in OHS was statistically higher (22.1 versus 20.5, p<0.001) for cementless implants, this small difference is unlikely to be clinically important. In males, revision risk was significantly higher in cementless (HR = 1.95, p = 0.003) and resurfacing implants, HR = 3.46, p<0.001), with no differences in OHS. Material costs were lowest with the reference implant (cemented, range £1103 to £1524) and highest with cementless implants (£1928 to £4285). Limitations include the design of the study, which is intrinsically vulnerable to omitted variables, a paucity of long-term implant survival data (reflecting the duration of data collection), the possibility of revision under-reporting, response bias within PROMs data, and issues associated with current outcome scoring systems, which may not accurately reflect level of improvement in some patients. Conclusions Cement fixation, using a polyethylene cup and a standard sized head offers good outcomes, with the lowest risks and at the lowest costs. The most commonly used cementless and resurfacing implants were associated with higher risk of revision and were more costly, while perceptions of improved function and longevity were unsupported. PMID:26561859

  6. Factors affecting the cement penetration of a hip resurfacing implant: an in vitro study.

    PubMed

    Howald, R; Kesteris, U; Klabunde, R; Krevolin, J

    2006-01-01

    An understanding of how the cementing technique influences cement penetration is important for surgeons to plan and conduct hip resurfacing procedures. Therefore the aim of this study is to determine the influence of the following parameters on cement penetration: use of pulse lavage, type of cement, and the standing period of the cement. Nine fresh frozen paired whole cadaver femora were used to investigate cement penetration. The femora were divided into three paired groups: (A) compared the use of pulse lavage to no pulse lavage, (B) compared two low viscosity bone cements SULCEM-3 (Zimmer GmbH, Switzerland) and Surgical Simplex (Stryker Orthopaedics, USA), and (C) compared bone cement viscosities using standing times of 1.5 min. and 3 min. The Durom Hip Resurfacing implant (Zimmer GmbH, Switzerland) was used in all groups. A single slice was taken out of the center of each head. Cement penetration ratio (penetration area divided by the bone area enclosed by implant) and mean cement penetration depth were measured. Cement penetration is increased using pulse lavage, and has the tendency to increase with increasing the cement standing time from 1.5 to 3 min. No difference in cement penetration was found when different cement brands of comparable viscosity were used. PMID:19219834

  7. Hip-inspired implant for revision of failed reverse shoulder arthroplasty with severe glenoid bone loss

    PubMed Central

    2014-01-01

    Background and purpose Glenoid reconstruction and inverted glenoid re-implantation is strongly advocated in revisions of failed reverse shoulder arthroplasty (RSA). Nevertheless, severe glenoid deficiency may preclude glenoid reconstruction and may dictate less favorable solutions, such as conversion to hemiarthropasty or resection arthropasty. The CAD/CAM shoulder (Stanmore Implants, Elstree, UK), a hip arthroplasty-inspired implant, may facilitate glenoid component fixation in these challenging revisions where glenoid reconstruction is not feasible. We questioned (1) whether revision arthroplasty with the CAD/CAM shoulder would alleviate pain and improve shoulder function in patients with failed RSA, not amenable to glenoid reconstruction, (2) whether the CAD/CAM hip-inspired glenoid shell would enable secure and durable glenoid component fixation in these challenging revisions. Patients and methods 11 patients with failed RSAs and unreconstructable glenoids underwent revision with the CAD/CAM shoulder and were followed-up for mean 35 (28–42) months. Clinical outcomes included the Oxford shoulder score, subjective shoulder value, pain rating, physical examination, and shoulder radiographs. Results The average Oxford shoulder score and subjective shoulder value improved statistically significantly after the revision from 50 to 33 points and from 17% to 48% respectively. Pain rating at rest and during activity improved significantly from 5.3 to 2.3 and from 8.1 to 3.8 respectively. Active forward flexion increased from 25 to 54 degrees and external rotation increased from 9 to 21 degrees. 4 patients required reoperation for postoperative complications. No cases of glenoid loosening occurred. Interpretation The CAD/CAM shoulder offers an alternative solution for the treatment of failed RSA that is not amenable to glenoid reconstruction. PMID:24650026

  8. Proposed frequencies of a vibrator used for implant retrieval at the time of hip joint revision surgery.

    PubMed

    Roychowdhury, Amit; Hayes, Westley; Rasquinha, Vijay J; Saha, Subrata

    2009-01-01

    The number and the rate of success of hip implantation surgeries have increased significantly during last thirty years, not only in the USA, but also throughout the world. It has been reported that the failure rates of implanted hip joints are less than 8% after 10 years, and less than 20% after twenty years. Failures occur directly or indirectly due to wear, stress shielding and infection. Revision surgery is needed for those failed implant replacements. In the future, as the elderly population increases, the frequency of this type of revision surgery will also increase. At the time of revision surgery, removal of the existing cemented femoral implant can be a problem for the surgeon. Use of a vibrator for loosening of the existing cement layer between the bone and the implant may be a helpful solution. In this study, we investigated the optimum resonance frequencies of such a vibrator that might be used to loosen the cement layer easily and efficiently. Natural frequencies of different-sized implants and of different materials were determined. For harmonic analysis, CT scan data of a femur was processed in the image processing software MIMICS. Then the outline of the total hip was modeled and was analyzed by the finite element software ANSYS. The required portion of the femoral part was edited, implant and cement layer were introduced in that model, and elements were generated in that FEA software. Then elements of the femoral part, except the cement layer and the implant, were sent to MIMICS software again for assignment of different Youngs modulus of each element, which are proportionate to their densities. Then the elements were brought back to the FEA software. The harmonic analysis was performed for the total model in the FEA software ANSYS. For that particular boundary condition, the first three natural frequencies of the three types of implant sizes and materials varied by a maximum of 7-8%. Results of the numerical harmonic analysis showed that at the bone-cement interface, the resonance frequencies were at the ranges of 4 to 6 Hz, 26 to 29 Hz, and 43 to 49 Hz. The vibration response was similar for three cement-bone interface locations examined. This suggests that a vibrator that will produce a resonance frequency response may cause cracks in the bone-cement mantle and thus may facilitate the removal of the failed femoral component. Retrieval of hip implant may be easier using a vibrator in that band of frequencies with a moderate amplitude. The magnitude of those frequencies may not differ significantly from implant to implant as the natural frequencies of different types of implant, for that particular boundary conditions, are within a close range. PMID:20666715

  9. Microfocus study of metal distribution and speciation in tissue extracted from revised metal on metal hip implants

    NASA Astrophysics Data System (ADS)

    Hart, Alister J.; Sandison, Ann; Quinn, Paul; Sampson, Barry; Atkinson, Kirk D.; Skinner, John A.; Goode, Angela; Powell, Jonathan J.; Mosselmans, J. Frederick W.

    2009-11-01

    Unexplained tissue inflammation in metal-on-metal hip replacements is suspected to be caused by implant-derived nanoparticles. The aim of this study was to investigate the nature of the metal particles in tissue surrounding metal-on-metal (MOM) hips that has been extracted during revision. Mapping of tissue surrounding the failed MOM hips was performed using microfocus X-ray Fluorescence (XRF). This revealed mainly Cr which was localized to the cellular regions. There was co-localisation of Co, were present, to areas of high Cr abundance. XANES of the tissue and appropriate standards revealed that the most common species were Cr(III) and Co(II). EXAFS analysis of the tissue and various metal standards revealed that the most abundant implant-related species was Cr(III) phosphate. Different tissue preparation methods, including frozen sectioning, were examined but were found not to affect the distribution or speciation of the metals in the tissue.

  10. In vitro macrophage response to nanometer-size particles from materials used in hip implants

    NASA Astrophysics Data System (ADS)

    VanOs, Robilyn

    Wear particle-induced inflammation leading to periprosthetic osteolysis remains a major cause of hip implant failure. As polyethylene particles from conventional metal-on-polyethylene implants have been associated with these failures, an interest in lower wear metal-on-metal (MM) bearings has emerged. However, the biological effects of nanometer-size chromium oxide particles, predominant type of wear particles produced by MM implants, remain mostly unknown. Therefore, this study aimed to determine the cytotoxicity of nanometer-size Cr2O3 particles on macrophages in vitro, by analyzing their effects on cell mortality and cytokine release and comparing them with those of similarly-sized alumina (Al2O3) particles (known to be relatively bioinert). Results showed that at high concentrations, nanometer-size Cr2O3 particles can be cytotoxic to macrophages, inducing significant decreases in total cell numbers and increases in necrosis. Results also showed that, at high concentrations, the cytotoxicity of Cr 2O3 particles was overall higher than that of Al2O 3 particles, even though Cr2O3 and Al2O 3 are both stable forms of ceramic materials. However, it appeared to be lower than that of previously reported conventional polyethylene and CoCrMo particles. Therefore, chromium oxide particles may not be the main culprit in initiating the inflammatory reaction in MM periprosthetic tissues.

  11. Comparative Effectiveness of Ceramic-on-Ceramic Implants in Stemmed Hip Replacement

    PubMed Central

    Sedrakyan, Art; Graves, Stephen; Bordini, Barbara; Pons, Miquel; Havelin, Leif; Mehle, Susan; Paxton, Elizabeth; Barber, Thomas; Cafri, Guy

    2014-01-01

    Background: The rapid decline in use of conventional total hip replacement with a large femoral head size and a metal-on-metal bearing surface might lead to increased popularity of ceramic-on-ceramic bearings as another hard-on-hard alternative that allows implantation of a larger head. We sought to address comparative effectiveness of ceramic-on-ceramic and metal-on-HXLPE (highly cross-linked polyethylene) implants by utilizing the distributed health data network of the ICOR (International Consortium of Orthopaedic Registries), an unprecedented collaboration of national and regional registries and the U.S. FDA (Food and Drug Administration). Methods: A distributed health data network was developed by the ICOR and used in this study. The data from each registry are standardized and provided at a level of aggregation most suitable for the detailed analysis of interest. The data are combined across registries for comprehensive assessments. The ICOR coordinating center and study steering committee defined the inclusion criteria for this study as total hip arthroplasty performed without cement from 2001 to 2010 in patients forty-five to sixty-four years of age with osteoarthritis. Six national and regional registries (Kaiser Permanente and HealthEast in the U.S., Emilia-Romagna region in Italy, Catalan region in Spain, Norway, and Australia) participated in this study. Multivariate meta-analysis was performed with use of linear mixed models, with survival probability as the unit of analysis. We present the results of the fixed-effects model and include the results of the random-effects model in an appendix. SAS version 9.2 was used for all analyses. We first compared femoral head sizes of >28 mm and ≤28 mm within ceramic-on-ceramic implants and then compared ceramic-on-ceramic with metal-on-HXLPE. Results: A total of 34,985 patients were included; 52% were female. We found a lower risk of revision associated with use of ceramic-on-ceramic implants when a larger head size was used (HR [hazard ratio] = 0.73, 95% CI [confidence interval] = 0.60 to 0.88, p = 0.001). Use of smaller-head-size ceramic-on-ceramic bearings was associated with a higher risk of failure compared with metal-on-HXLPE bearings (HR = 1.36, 95% CI = 1.09 to 1.68, p = 0.006). Use of large-head-size ceramic-on-ceramic bearings was associated with a small protective effect relative to metal-on-HXLPE bearings (not subdivided by head size) in years zero to two, but this difference dissipated over the longer term. Conclusions: Our multinational study based on a harmonized, distributed network showed that use of ceramic-on-ceramic implants with a smaller head size in total hip arthroplasty without cement was associated with a higher risk of revision compared with metal-on-HXLPE and >28-mm ceramic-on-ceramic implants. These findings warrant careful reflection by regulatory and clinical communities and wide dissemination to patients for informed decision-making regarding such surgery. PMID:25520417

  12. Comparison and Combination of Dual-Energy- and Iterative-Based Metal Artefact Reduction on Hip Prosthesis and Dental Implants

    PubMed Central

    Bongers, Malte N.; Schabel, Christoph; Thomas, Christoph; Raupach, Rainer; Notohamiprodjo, Mike; Nikolaou, Konstantin; Bamberg, Fabian

    2015-01-01

    Purpose To compare and combine dual-energy based and iterative metal artefact reduction on hip prosthesis and dental implants in CT. Material and Methods A total of 46 patients (women:50%,mean age:63±15years) with dental implants or hip prostheses (n = 30/20) were included and examined with a second-generation Dual Source Scanner. 120kV equivalent mixed-images were derived from reconstructions of the 100/Sn140kV source images using no metal artefact reduction (NOMAR) and iterative metal artefact reduction (IMAR). We then generated monoenergetic extrapolations at 130keV from source images without IMAR (DEMAR) or from source images with IMAR, (IMAR+DEMAR). The degree of metal artefact was quantified for NOMAR, IMAR, DEMAR and IMAR+DEMAR using a Fourier-based method and subjectively rated on a five point Likert scale by two independent readers. Results In subjects with hip prosthesis, DEMAR and IMAR resulted in significantly reduced artefacts compared to standard reconstructions (33% vs. 56%; for DEMAR and IMAR; respectively, p<0.005), but the degree of artefact reduction was significantly higher for IMAR (all p<0.005). In contrast, in subjects with dental implants only IMAR showed a significant reduction of artefacts whereas DEMAR did not (71%, vs. 8% p<0.01 and p = 0.1; respectively). Furthermore, the combination of IMAR with DEMAR resulted in additionally reduced artefacts (Hip prosthesis: 47%, dental implants 18%; both p<0.0001). Conclusion IMAR allows for significantly higher reduction of metal artefacts caused by hip prostheses and dental implants, compared to a dual energy based method. The combination of DE-source images with IMAR and subsequent monoenergetic extrapolation provides an incremental benefit compared to both single methods. PMID:26600188

  13. A preliminary biomechanical assessment of a polymer composite hip implant using an infrared thermography technique validated by strain gage measurements.

    PubMed

    Bougherara, Habiba; Rahim, Ehsan; Shah, Suraj; Dubov, Anton; Schemitsch, Emil H; Zdero, Rad

    2011-07-01

    With the resurgence of composite materials in orthopaedic applications, a rigorous assessment of stress is needed to predict any failure of bone-implant systems. For current biomechanics research, strain gage measurements are employed to experimentally validate finite element models, which then characterize stress in the bone and implant. Our preliminary study experimentally validates a relatively new nondestructive testing technique for orthopaedic implants. Lock-in infrared (IR) thermography validated with strain gage measurements was used to investigate the stress and strain patterns in a novel composite hip implant made of carbon fiber reinforced polyamide 12 (CF/PA12). The hip implant was instrumented with strain gages and mechanically tested using average axial cyclic forces of 840 N, 1500 N, and 2100 N with the implant at an adduction angle of 15 deg to simulate the single-legged stance phase of walking gait. Three-dimensional surface stress maps were also obtained using an IR thermography camera. Results showed almost perfect agreement of IR thermography versus strain gage data with a Pearson correlation of R(2) = 0.96 and a slope = 1.01 for the line of best fit. IR thermography detected hip implant peak stresses on the inferior-medial side just distal to the neck region of 31.14 MPa (at 840 N), 72.16 MPa (at 1500 N), and 119.86 MPa (at 2100 N). There was strong correlation between IR thermography-measured stresses and force application level at key locations on the implant along the medial (R(2) = 0.99) and lateral (R(2) = 0.83 to 0.99) surface, as well as at the peak stress point (R(2) = 0.81 to 0.97). This is the first study to experimentally validate and demonstrate the use of lock-in IR thermography to obtain three-dimensional stress fields of an orthopaedic device manufactured from a composite material. PMID:21823752

  14. Implant based differences in adverse local tissue reaction in failed total hip arthroplasties: a morphological and immunohistochemical study

    PubMed Central

    2014-01-01

    Background Adverse local tissue reaction (ALTR) is characterized by periprosthetic soft tissue inflammation composed of a mixed inflammatory cell infiltrate, extensive soft tissue necrosis, and vascular changes. Multiple hip implant classes have been reported to result in ALTR, and clinical differences may represent variation in the soft tissue response at the cellular and tissue levels. The purpose of this study was to describe similarities and differences in periprosthetic tissue structure, organization, and cellular composition by conventional histology and immunohistochemistry in ALTR resulting from two common total hip arthroplasty (THA) implant classes. Methods Consecutive patients presenting with ALTR from two major hip implant classes (N = 54 patients with Dual-Modular Neck implant; N = 14 patients with Metal-on-Metal implant) were identified from our prospective Osteolysis Tissue Database and Repository. Clinical characteristics including age, sex, BMI, length of implantation, and serum metal ion levels were recorded. Retrieved synovial tissue morphology was graded using light microscopy and cellular composition was assessed using immunohistochemistry. Results Length of implantation was shorter in the DMN group versus MoM THA group (21.3 [8.4] months versus 43.6 [13.8] months respectively; p < 0.005) suggesting differences in implant performance. Morphologic examination revealed a common spectrum of neo-synovial proliferation and necrosis in both groups. Macrophages were more commonly present in diffuse sheets (Grade 3) in the MoM relative to DMN group (p = 0.016). Perivascular lymphocytes with germinal centers (Grade 4) were more common in the DMN group, which trended towards significance (p = 0.066). Qualitative differences in corrosion product morphology were seen between the two groups. Immunohistochemistry showed features of a CD4 and GATA-3 rich lymphocyte reaction in both implants, with increased ratios of perivascular T-cell relative to B-cell markers in the DMN relative to the MoM group (p = 0.032). Conclusion Our results demonstrate that both implant classes display common features of neo-synovial proliferation and necrosis with a CD4 and GATA-3 rich inflammatory infiltrate. Qualitative differences in corrosion product appearance, macrophage morphology, and lymphocyte distributions were seen between the two implant types. Our data suggests that ALTR represents a histological spectrum with implant-based features. PMID:25242891

  15. Comparative analysis of different hip implants within a realistic human model located inside a 1.5T MRI whole body RF coil.

    PubMed

    Kozlov, Mikhail; Noetscher, Gregory M; Nazarian, Ara; Makarov, Sergey N

    2015-08-01

    Temperature rise in surrounding tissues of a large orthopedic metallic implant subject to MRI is a significant point of concern today. Numerical electromagnetic and thermal modeling offers a way to model this complex problem with a sufficient degree of accuracy. We developed a workflow for realistic implant modeling, which includes an MRI coil, a multi-tissue human model, and accurately registered hip implants. We also obtained differences in the power loss density rises generated due to the presence of three hip implants placed in a phantom or a realistic human model, located inside a 1.5 T coil. PMID:26738127

  16. Handling modular hip implants in model-based RSA: combined stem-head models.

    PubMed

    Prins, A H; Kaptein, B L; Stoel, B C; Nelissen, R G H H; Reiber, J H C; Valstar, E R

    2008-10-20

    Migration measurements of hip prostheses using marker-based Roentgen stereophotogrammetric analysis (RSA) require the attachment of markers to the prostheses. The model-based approach, which does not require these markers, is, however, less precise. One of the reasons may be the fact that the spherical head has not been modelled. Therefore, we added a 3D surface model of the spherical head and estimated the position and orientation of the combined stem-head model. The new method using a combined stem-head model was compared in a phantom study on five prostheses (of different types) and in a clinical study using double examinations of implanted hip prostheses, with two existing methods: a standard model-based approach and one using elementary geometrical shapes. The combined model showed the highest precision for the rotation about the longitudinal axis in the phantom experiments. With a standard deviation of 0.69 degrees it showed a significant improvement (p=0.02) over the model-based approach (0.96 degrees ) on the phantom data, but no improvement on the clinical data. Overall, the use of elementary geometrical shapes was worse with respect to the model-based approach, with a standard deviation of 1.02 degrees on the phantom data and 0.79 degrees on the clinical data. This decrease in precision was significant (p<0.01) on the clinical data. With relatively small differences in the other migration directions, these results demonstrate that the new method with a combined stem-head model can be a useful alternative to the standard model-based approach. PMID:18805532

  17. Long Term Outcomes of Total Hip Arthroplasty With Custom Made Femoral Implants in Patients With Congenital Disease of Hip.

    PubMed

    Pakos, Emilios E; Stafilas, Kosmas S; Tsovilis, Aristomenis E; Vafiadis, John N; Kalos, Nikolaos K; Xenakis, Theodoros A

    2015-12-01

    We evaluated the outcomes of total hip arthroplasty in 67 patients (86 hips) with congenital hip disease and excessive abnormal anatomy of the proximal femur with the use of custom-made femoral stems. The design of the stem was based on CT data following the principles of CAD-CAE-CAM technique. No serious complications attributed to the femoral stem were seen. Within a median follow-up of 127.5 months the 10-year survival of any of the components was 95.4% and respective value when aseptic loosening of the stem was considered was 98.1%. Patients with high dislocations had a 10-fold risk for loosening compared to those with low dislocations. No other parameter was associated with outcomes. The clinical and radiological evaluation was in consistency with the above outcomes. PMID:26187384

  18. A comparative FEA of the debonding process in different concepts of cemented hip implants.

    PubMed

    Pérez, M A; García-Aznar, J M; Doblaré, M; Seral, B; Seral, F

    2006-07-01

    Debonding of the stem-cement interface and damage accumulation in the cement mantle are basic events that contribute to the long-term failure of cemented hip reconstructions. In this work, a numerical study with these two processes coupled is presented. On the one hand, debonding of the stem-cement interface was simulated by means of a cohesive surface theory that was implemented into an interface finite element. This interface model includes a tensile-shear behavior law, the fatigue failure of the interface, and the friction evolution between both surfaces. On the other hand, damage accumulation in the cement was formulated through the theory of continuum damage mechanics, considering cement damage due to tension, creep under compression, crack closure effects, non-linear damage accumulation and cement residual stresses appearing during polymerisation. This methodology was applied to simulate and compare the degradation process of the cement and stem-cement interface in four different concepts of design: Exeter, Charnley, Elite Plus and ABG II stems. As the actual mechanical properties of the surface of each specific prosthesis are not known, we assumed the same for all of them, distinguishing between polished and matt surfaces. With this assumption, the predicted results showed that the debonding process is very different for each implant depending on the stem geometry. Lower cement deterioration was obtained for the Exeter and ABG II stems, while the lowest stem-cement interface debonding was produced in the Exeter and the Elite Plus stems. PMID:16257253

  19. IN VIVO SEVERE CORROSION AND HYDROGEN EMBRITTLEMENT OF RETRIEVED MODULAR BODY TITANIUM ALLOY HIP-IMPLANTS

    PubMed Central

    Rodrigues, Danieli C.; Urban, Robert M.; Jacobs, Joshua J.; Gilbert, Jeremy L.

    2009-01-01

    Titanium alloys are widely used in total-joint replacements due to a combination of outstanding mechanical properties, biocompatibility, passivity and corrosion resistance. Nevertheless, retrieval studies have pointed out that these materials can be subjected to localized or general corrosion in modular interfaces when mechanical abrasion of the oxide film (fretting) occurs. Modularity adds large crevice environments, which are subject to micromotion between contacting interfaces and differential aeration of the surface. Titanium alloys are also known to be susceptible to hydrogen absorption, which can induce precipitation of hydrides and subsequent brittle failure. In this work, the surface of three designs of retrieved hip-implants with Ti-6Al-4V/Ti-6Al-4V modular taper interfaces in the stem were investigated for evidence of severe corrosion and precipitation of brittle hydrides during fretting-crevice corrosion in the modular connections. The devices were retrieved from patients and studied by means of scanning electron microscopy (SEM), x-ray diffraction (XRD) and chemical analysis. The surface qualitative investigation revealed severe corrosion attack in the mating interfaces with evidence of etching, pitting, delamination and surface cracking. In vivo hydrogen embrittlement was shown to be a mechanism of degradation in modular connections resulting from electrochemical reactions induced in the crevice environment of the tapers during fretting-crevice corrosion. PMID:18683224

  20. In vivo severe corrosion and hydrogen embrittlement of retrieved modular body titanium alloy hip-implants.

    PubMed

    Rodrigues, Danieli C; Urban, Robert M; Jacobs, Joshua J; Gilbert, Jeremy L

    2009-01-01

    Titanium alloys are widely used in total-joint replacements due to a combination of outstanding mechanical properties, biocompatibility, passivity, and corrosion resistance. Nevertheless, retrieval studies have pointed out that these materials can be subjected to localized or general corrosion in modular interfaces when mechanical abrasion of the oxide film (fretting) occurs. Modularity adds large crevice environments, which are subject to micromotion between contacting interfaces and differential aeration of the surface. Titanium alloys are also known to be susceptible to hydrogen absorption, which can induce precipitation of hydrides and subsequent brittle failure. In this work, the surface of three designs of retrieved hip-implants with Ti-6Al-4V/Ti-6Al-4V modular taper interfaces in the stem were investigated for evidence of severe corrosion and precipitation of brittle hydrides during fretting-crevice corrosion in the modular connections. The devices were retrieved from patients and studied by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), and chemical analysis. The surface qualitative investigation revealed severe corrosion attack in the mating interfaces with evidence of etching, pitting, delamination, and surface cracking. In vivo hydrogen embrittlement was shown to be a mechanism of degradation in modular connections resulting from electrochemical reactions induced in the crevice environment of the tapers during fretting-crevice corrosion. PMID:18683224

  1. N-Acetyl-Cysteine as Effective and Safe Chelating Agent in Metal-on-Metal Hip-Implanted Patients: Two Cases.

    PubMed

    Giampreti, Andrea; Lonati, Davide; Ragghianti, Benedetta; Ronchi, Anna; Petrolini, Valeria Margherita; Vecchio, Sarah; Locatelli, Carlo Alessandro

    2016-01-01

    Systemic toxicity associated with cobalt (Co) and chromium (Cr) containing metal hip alloy may result in neuropathy, cardiomyopathy, and hypothyroidism. However clinical management concerning chelating therapy is still debated in literature. Here are described two metal-on-metal hip-implanted patients in which N-acetyl-cysteine decreased elevated blood metal levels. A 67-year-old male who underwent Co/Cr hip implant in September 2009 referred to our Poison Control Centre for persisting elevated Co/Cr blood levels (from March 2012 to November 2014). After receiving oral high-dose N-acetyl-cysteine, Co/Cr blood concentrations dropped by 86% and 87% of the prechelation levels, respectively, and persisted at these latter concentrations during the following 6 months of follow-up. An 81-year-old female who underwent Co/Cr hip implant in January 2007 referred to our Centre for detection of high Co and Cr blood levels in June 2012. No hip revision was indicated. After a therapy with oral high-dose N-acetyl-cysteine Co/Cr blood concentrations decreased of 45% and 24% of the prechelation levels. Chelating agents reported in hip-implanted patients (EDTA, DMPS, and BAL) are described in few cases. N-acetyl-cysteine may provide chelating sites for metals and in our cases reduced Co and Cr blood levels and resulted well tolerable. PMID:27148463

  2. N-Acetyl-Cysteine as Effective and Safe Chelating Agent in Metal-on-Metal Hip-Implanted Patients: Two Cases

    PubMed Central

    Lonati, Davide; Ragghianti, Benedetta; Ronchi, Anna; Vecchio, Sarah; Locatelli, Carlo Alessandro

    2016-01-01

    Systemic toxicity associated with cobalt (Co) and chromium (Cr) containing metal hip alloy may result in neuropathy, cardiomyopathy, and hypothyroidism. However clinical management concerning chelating therapy is still debated in literature. Here are described two metal-on-metal hip-implanted patients in which N-acetyl-cysteine decreased elevated blood metal levels. A 67-year-old male who underwent Co/Cr hip implant in September 2009 referred to our Poison Control Centre for persisting elevated Co/Cr blood levels (from March 2012 to November 2014). After receiving oral high-dose N-acetyl-cysteine, Co/Cr blood concentrations dropped by 86% and 87% of the prechelation levels, respectively, and persisted at these latter concentrations during the following 6 months of follow-up. An 81-year-old female who underwent Co/Cr hip implant in January 2007 referred to our Centre for detection of high Co and Cr blood levels in June 2012. No hip revision was indicated. After a therapy with oral high-dose N-acetyl-cysteine Co/Cr blood concentrations decreased of 45% and 24% of the prechelation levels. Chelating agents reported in hip-implanted patients (EDTA, DMPS, and BAL) are described in few cases. N-acetyl-cysteine may provide chelating sites for metals and in our cases reduced Co and Cr blood levels and resulted well tolerable. PMID:27148463

  3. Wear behaviour of cobalt-chromium-molybdenum alloys used in metal-on-metal hip implants

    NASA Astrophysics Data System (ADS)

    Varano, Rocco

    The influence of carbon (C) content, microstructure, crystallography and mechanical properties on the wear behaviour of metal-on-metal (MM) hip implants made from commercially available cobalt-chromium-molybdenum (CoCrMo) alloys designated as American Society of Testing and Materials (ASTM) grade F1537, F75 and as-cast were studied in this work. The as-received bars of wrought CoCrMo alloys (ASTM F1537 of either about 0.05% or 0.26% C) were each subjected to various heat treatments to develop different microstructures. Pin and plate specimens were fabricated from each bar and were tested against each other using a linear reciprocating pin-on-plate apparatus in 25% by volume bovine serum solution. The applied normal load was 9.81 N and the reciprocating plate had a sinusoidal velocity with an average speed of 26 mm/s. The wear was measured gravimetrically and it was found to be most strongly affected by alloy C content, irrespective of grain size or carbide morphology. More precisely, the wear behaviour was directly correlated to the dissolved C content of the alloys. Increased C in solid-solution coincided with lower volumetric wear since C helps to stabilize the face-centred cubic (FCC) crystal structure thus limiting the amount of strain induced transformation (SIT) to the hexagonal close-packed crystal structure (HCP). Based on the observed surface twinning in and around the contact zone and the potentially detrimental effect of the HCP phase, it was postulated that the MM wear behaviour of CoCrMo alloys in the present study was controlled by a deformation mechanism, rather than corrosion or tribochemical reactions.

  4. Superelastic Orthopedic Implant Coatings

    NASA Astrophysics Data System (ADS)

    Fournier, Eric; Devaney, Robert; Palmer, Matthew; Kramer, Joshua; El Khaja, Ragheb; Fonte, Matthew

    2014-07-01

    The demand for hip and knee replacement surgery is substantial and growing. Unfortunately, most joint replacement surgeries will fail within 10-25 years, thereby requiring an arduous, painful, and expensive revision surgery. To address this issue, a novel orthopedic implant coating material ("eXalt") has been developed. eXalt is comprised of super elastic nitinol wire that is knit into a three-dimensional spacer fabric structure. eXalt expands in vivo to conform to the implantation site and is porous to allow for bone ingrowth. The safety and efficacy of eXalt were evaluated through structural analysis, mechanical testing, and a rabbit implantation model. The results demonstrate that eXalt meets or exceeds the performance of current coating technologies with reduced micromotion, improved osseointegration, and stronger implant fixation in vivo.

  5. Are Preformed Articulating Spacers Superior To Surgeon-Made Articulating Spacers in the Treatment Of PJI in THA? A Literature Review

    PubMed Central

    Citak, Mustafa; Masri, Bassam A.; Springer, Bryan; Argenson, Jean-Noel; Kendoff, Daniel O.

    2015-01-01

    Background and Purpose: Antibiotic-loaded cement spacers are typically manufactured by surgeons in the operating room. However, if the infecting organism is known preoperatively, the cement spacer can be fabricated (Spacer-G® or the InterSpace® Hip) in advance. It is unclear if preformed hip spacers are superior to surgeon-made hip spacers in the treatment of periprosthetic joint infection following primary THA. Methods: A literature review of the peer-reviewed literature indexed by MEDLINE and Embase was performed to identify studies reporting the outcomes of preformed and surgeon-made hip spacers in the treatment of infection following primary total hip arthroplasty (THA). A total of 43 articles met the inclusion criteria and were included in the analysis to compare the reinfection rate, Harris Hip Score (HHS) and spacer complication rates between surgeon-made and preformed hip spacers. Results and Interpretation: The analyzed studies included a total number of 1631 infected THA cases (n=1027 surgeonmade; n=604 preformed spacers). We found similar reinfection rates (6.0% surgeon-made, and 5.5% preformed spacers) and similar mean HHS at latest follow-up after reimplantation (HHS=84.3 surgeon-made, and HHS=81.8 preformed spacers) between both groups. However, patients treated with a surgeon-made articulating spacer had a higher spacer fracture rate compared to preformed articulating spacer. The use of preformed articulating spacers in the treatment of infected THA is not superior to surgeon-made articulating spacers regarding infection control and functional outcomes. However, the use of surgeon-made antibiotic spacers increased the risk of spacer fracture. PMID:26473023

  6. Spectral analysis of the sound produced during femoral broaching and implant insertion in uncemented total hip arthroplasty.

    PubMed

    Whitwell, George; Brockett, Claire L; Young, Steve; Stone, Martin; Stewart, Todd D

    2013-02-01

    Preparation of the proximal femur using incremental broaches to create the ideal cancellous bone envelope is an important technique to perfect in uncemented hip arthroplasty. To guide broaching adequacy and final implant position, the surgeon can use audible pitch changes produced by the femoral broach and definitive implant. The aim of this study was to characterise these pitch changes by analysing the sound spectra created by the first broach, last broach and implant using spectral analysis software. The last broach and implant introduction spectra demonstrated low-frequency (400-1200 Hz) spectral peaks that were not detected when using the first broach. These frequencies corresponded to the natural resonant frequency of a standing sound wave within the femoral bone canal (approximately 894 Hz) that was estimated using acoustic physics theory. The remaining spectral peaks were associated with transverse vibration modes produced by striking the metal broach handle and implant introducer and were a function of the constructs geometry and material properties. PMID:23513988

  7. No association between serum metal ions and implant fixation in large-head metal-on-metal total hip arthroplasty

    PubMed Central

    Søballe, Kjeld; Jakobsen, Stig Storgaard; Lorenzen, Nina Dyrberg; Mechlenburg, Inger; Stilling, Maiken

    2014-01-01

    Background The mechanism of failure of metal-on-metal (MoM) total hip arthroplasty (THA) has been related to a high rate of metal wear debris, which is partly generated from the head-trunnion interface. However, it is not known whether implant fixation is affected by metal wear debris. Patients and methods 49 cases of MoM THA in 41 patients (10 women) with a mean age of 52 (28–68) years were followed with stereoradiographs after surgery and at 1, 2, and 5 years to analyze implant migration by radiostereometric analysis (RSA). Patients also participated in a 5- to 7-year follow-up with measurement of serum metal ions, questionnaires (Oxford hip score (OHS) and Harris hip score (HHS)), and measurement of cup and stem positions and systemic bone mineral density. Results At 1–2 years, mean total translation (TT) was 0.04 mm (95% CI: –0.07 to 0.14; p = 0.5) for the stems; at 2–5 years, mean TT was 0.13 mm (95% CI: –0.25 to –0.01; p = 0.03), but within the precision limit of the method. For the cups, there was no statistically significant TT or total rotation (TR) at 1–2 and 2–5 years. At 2–5 years, we found 4 cups and 5 stems with TT migrations exceeding the precision limit of the method. There was an association between cup migration and total OHS < 40 (4 patients, 4 hips; p = 0.04), but there were no statistically significant associations between cup or stem migration and T-scores < –1 (n = 10), cup and stem positions, or elevated serum metal ion levels (> 7µg/L (4 patients, 6 hips)). Interpretation Most cups and stems were well-fixed at 1–5 years. However, at 2–5 years, 4 cups and 5 stems had TT migrations above the precision limits, but these patients had serum metal ion levels similar to those of patients without measurable migrations, and they were pain-free. Patients with serum metal ion levels > 7 µg/L had migrations similar to those in patients with serum metal ion levels < 7 µg/L. Metal wear debris does not appear to influence the fixation of hip components in large-head MoM articulations at medium-term follow-up. PMID:24847790

  8. Toxicology-based cancer causation analysis of CoCr-containing hip implants: a quantitative assessment of genotoxicity and tumorigenicity studies.

    PubMed

    Christian, Whitney V; Oliver, Lindsay D; Paustenbach, Dennis J; Kreider, Marisa L; Finley, Brent L

    2014-09-01

    In this paper, quantitative methods were used to evaluate the weight of evidence regarding a causative relationship between cobalt-chromium (CoCr)-containing hip implants and increased cancer risk. We reviewed approximately 80 published papers and identified no-observed-adverse-effect level (NOAEL) and/or lowest-observed-adverse-effect level (LOAEL) values for specific endpoints of interest: genotoxic effects from in vitro studies with human cell lines as well as genotoxicity and tumor formation in animal bioassays. Test articles included Co particles and ions, Cr particles and ions, and CoCr alloy particles as well as CoCr alloy implants. The NOAEL/LOAEL values were compared with body burdens of Co/Cr particles and ions we calculated to exist in systemic tissues of hip implant patients under normal and excessive wear conditions. We found that approximately 40 tumor bioassays have been conducted with CoCr alloy implants or Co/Cr particles and ions at levels hundreds to thousands of times higher than those present in hip implant patients, and none reported a statistically significant increased incidence of systemic tumors. Results from in vitro and in vivo genotoxicity assays, which are relatively less informative owing to false positives and other factors, also indicated that DNA effects would be highly unlikely to occur as a result of wear debris from a CoCr implant. Hence, the toxicological weight of evidence suggests that CoCr-containing hip implants are unlikely to be associated with an increased risk of systemic cancers, which is consistent with published and ongoing cancer epidemiology studies involving patients with CoCr hip implants. PMID:25080401

  9. A modified porous tantalum implant technique for osteonecrosis of the femoral head: survivorship analysis and prognostic factors for radiographic progression and conversion to total hip arthroplasty

    PubMed Central

    Liu, Yaosheng; Su, Xiuyun; Zhou, Shiguo; Wang, Lei; Wang, Cheng; Liu, Shubin

    2015-01-01

    Tantalum rod implant following core decompression is reported to be effective in early stage of osteonecrosis of the femoral head (ONFH). The purpose of this study was to assess the survivorship and prognostic factors for radiographic progression and conversion to total hip arthroplasty (THA) after treatment with a modified tantalum implant technology. 59 consecutive hips (45 patients) in whom ONFH was treated with core decompression, impaction bone grafting of 2 mm-composite bone filling material, and insertion of a porous tantalum implant. 57 hips (44 patients, mean age 43 years, range 21 to 70 years) with Steinberg Stage I-IVA ONFH were available for follow-up at a mean of 44.8 months (rang, 11 to 62 months). Outcome measures included HHS (Harris Hip Score), radiographic outcome, and survivorship analysis with reversion to THA. Radiographic progression occurred in 17 hips (17/57, 29.82%). 11 hips (11/57, 19.30%) were converted to THA. The overall survival rate was 72.49% at 60 months post-operatively. After logistic regression analysis, corticosteroid use and bone marrow edema were found to be predictors of radiographic progression. The Cox proportional-hazard model revealed that bone marrow edema was an independent prognostic factor for conversion to THA. This modified technology may make patients avoid the use of corticosteroid, especially those without bone marrow edema, and obtains encouraging survival rates and a delay in or prevention of THA. PMID:25932121

  10. Are all metal-on-metal hip revision operations contributing to the National Joint Registry implant survival curves?

    PubMed Central

    Sabah, S. A.; Henckel, J.; Koutsouris, S.; Rajani, R.; Hothi, H.; Skinner, J. A.; Hart, A. J.

    2016-01-01

    Aims The National Joint Registry for England, Wales and Northern Ireland (NJR) has extended its scope to report on hospital, surgeon and implant performance. Data linkage of the NJR to the London Implant Retrieval Centre (LIRC) has previously evaluated data quality for hip primary procedures, but did not assess revision records. Methods We analysed metal-on-metal hip revision procedures performed between 2003 and 2013. A total of 69 929 revision procedures from the NJR and 929 revised pairs of components from the LIRC were included. Results We were able to link 716 (77.1%) revision procedures on the NJR to the LIRC. This meant that 213 (22.9%) revision procedures at the LIRC could not be identified on the NJR. We found that 349 (37.6%) explants at the LIRC completed the full linkage process to both NJR primary and revision databases. Data completion was excellent (> 99.9%) for revision procedures reported to the NJR. Discussion This study has shown that only approximately one third of retrieved components at the LIRC, contributed to survival curves on the NJR. We recommend prospective registry-retrieval linkage as a tool to feedback missing and erroneous data to the NJR and improve data quality. Take home message: Prospective Registry – retrieval linkage is a simple tool to evaluate and improve data quality on the NJR. Cite this article: Bone Joint J 2016;98-B:33–9. PMID:26733513

  11. Distributed Analysis of Hip Implants Using Six National and Regional Registries: Comparing Metal-on-Metal with Metal-on-Highly Cross-Linked Polyethylene Bearings in Cementless Total Hip Arthroplasty in Young Patients

    PubMed Central

    Furnes, Ove; Paxton, Elizabeth; Cafri, Guy; Graves, Stephen; Bordini, Barbara; Comfort, Thomas; Rivas, Moises Coll; Banerjee, Samprit; Sedrakyan, Art

    2014-01-01

    Background: The regulation of medical devices has attracted controversy recently because of problems related to metal-on-metal hip implants. There is growing evidence that metal-on-metal implants fail early and cause local and systemic complications. However, the failure associated with metal-on-metal head size is not consistently documented and needs to be communicated to patients and surgeons. The purpose of this study is to compare implant survival of metal on metal with that of metal on highly cross-linked polyethylene. Methods: Using a distributed health data network, primary total hip arthroplasties were identified from six national and regional total joint arthroplasty registries (2001 to 2010). Inclusion criteria were patient age of forty-five to sixty-four years, cementless total hip arthroplasties, primary osteoarthritis diagnosis, and exclusion of the well-known outlier implant ASR (articular surface replacement). The primary outcome was revision for any reason. A meta-analysis of survival probabilities was performed with use of a fixed-effects model. Metal-on-metal implants with a large head size of >36 mm were compared with metal-on-highly cross-linked polyethylene implants. Results: Metal-on-metal implants with a large head size of >36 mm were used in 5172 hips and metal-on-highly cross-linked polyethylene implants were used in 14,372 hips. Metal-on-metal total hip replacements with a large head size of >36 mm had an increased risk of revision compared with metal-on-highly cross-linked polyethylene total hip replacements with more than two years of follow-up, with no difference during the first two years after implantation. The results of the hazard ratios (and 95% confidence intervals) from the multivariable model at various durations of follow-up were 0.95 (0.74 to 1.23) at zero to two years (p = 0.698), 1.42 (1.16 to 1.75) at more than two years to four years (p = 0.001), 1.78 (1.45 to 2.19) at more than four years to six years (p < 0.001), and 2.15 (1.63 to 2.83) at more than six years to seven years (p < 0.001). Conclusions: We conducted a comparison of large-head-size, metal-on-metal implants and metal-on-highly cross-linked polyethylene implants in younger patients with uncemented fixation. We found consistent and strong evidence worldwide that large-head-size, metal-on-metal implants were associated with increased risk of revision after two years compared with metal-on-highly cross-linked polyethylene implants, with the effect becoming more pronounced over time. PMID:25520416

  12. Information for Patients Who Have Metal-on-Metal Hip Implants

    MedlinePlus

    ... their implants. These problems included: General hypersensitivity reaction (skin rash) Cardiomyopathy Neurological changes including sensory changes (auditory, or visual impairments) Psychological status change ( ...

  13. Multi-scalar analysis of hip implant components using modal decomposition

    NASA Astrophysics Data System (ADS)

    Grandjean, J.; Le Goic, G.; Favreliere, H.; Ledoux, Y.; Samper, S.; Formosa, F.; Devun, L.; Gradel, T.

    2012-12-01

    This paper presents a metrological analysis of hip prosthesis components. When changing ceramic prostheses, the surgeon sometimes finds traces of alloy lying in the insert or the femoral head. These traces can be thin and accurate or as a wide band. From the measurements made on the contact areas of hip prosthesis components, we analyse these phenomena by highlighting the defects of form, waviness and roughness of these surfaces using a novel geometric parameterization (namely modal parameterization). The aim of this work is to isolate these defects to characterize the prostheses components. We show that this parameterization allows a multi-scale analysis of surfaces regardless of the type of wear of the prosthesis, and that the results offer some relevant explanations to the analysis of visible damage on the prostheses. In a later study, we are going to analyse the defects influence on the alteration of the performance of hip prostheses.

  14. Bisphosphonate Use and Risk of Implant Revision after Total Hip/Knee Arthroplasty: A Meta-Analysis of Observational Studies

    PubMed Central

    Teng, Songsong; Yi, Chengqing; Krettek, Christian; Jagodzinski, Michael

    2015-01-01

    Objective Several studies investigated the association between bisphosphonate use and the risk of implant revision after total hip or knee arthroplasty (THA or TKA); However, the findings were inconsistent. We performed this meta-analysis to evaluate the overall relative risk of such an event. Methods We searched the PubMed, EMBASE and Cochrane library databases to identify relevant publications on April 22, 2015. To calculate the pooled risk ratios (RRs) with 95% confidential intervals (CIs), a fixed- or random-effects model was applied based on the heterogeneity across studies. Results Three cohort studies and one case-control study were included in this meta-analysis. Compared with the bisphosphonate nonusers, the patients who used bisphosphonates for a long period of time had a significantly decreased risk of implant revision after THA/TKA (summary adjusted RR = 0.48, 95% CI: 0.38–0.61), and the summary adjusted RRs for the users who underwent THA and those who underwent TKA were 0.47 (95% CI: 0.36–0.61) and 0.45 (95% CI: 0.21–0.95), respectively. Conclusions Long-term use of bisphosphonates is correlated with a significantly decreased risk of implant revision after THA/TKA. However, due to limited number of the included studies, the findings of the present study should be treated with caution. More well-designed studies are required to further confirm our findings. PMID:26444555

  15. The biomechanical effect of anteversion and modular neck offset on stress shielding for short-stem versus conventional long-stem hip implants.

    PubMed

    Goshulak, Peter; Samiezadeh, Saeid; Aziz, Mina S R; Bougherara, Habiba; Zdero, Radovan; Schemitsch, Emil H

    2016-03-01

    Short-stem hip implants are increasingly common since they preserve host bone stock and presumably reduce stress shielding by improving load distribution in the proximal femur. Stress shielding may lead to decreased bone density, implant loosening, and fracture. However, few biomechanical studies have examined short-stem hip implants. The purpose of this study was to compare short-stem vs. standard length stemmed implants for stress shielding effects due to anteversion-retroversion, anterior-posterior position, and modular neck offset. Twelve artificial femurs were implanted with either a short-stem modular-neck implant or a conventional length monolithic implant in 0° or 15° of anteversion. Three modular neck options were tested in the short-stem implants. Three control femurs remained intact. Femurs were mounted in adduction and subjected to axial loading. Strain gauge values were collected to validate a Finite Element (FE) model, which was used to simulate the full range of physiologically possible anteversion and anterior-posterior combinations (n = 25 combinations per implant). Calcar stress was compared between implants and across each implant's range of anteversion using one and two-way ANOVA. Stress shielding was defined as the overall change in stress compared to an intact femur. The FE model compared well with experimental strains (intact: slope = 0.898, R = 0.943; short-stem: slope = 0.731, R = 0.948; standard-stem: slope = 0.743, R = 0.859); correction factors were used to adjust slopes to unity. No implant anteversion showed significant reduction in stress shielding (α = 0.05, p > 0.05). Stress shielding was significantly higher in the standard-stem implant (63% change from intact femur, p < 0.001) than in short-stem implants (29-39% change, p < 0.001). Short-stem implants reduce stress shielding compared to standard length stemmed implants, while implant anteversion and anterior-posterior position had no effect. Therefore, short-stem implants have a greater likelihood of maintaining calcar bone strength in the long term. PMID:26774671

  16. Revision total hip arthroplasty using a modular femoral implant in Paprosky type III and IV femoral bone loss.

    PubMed

    Desai, Rasesh R; Malkani, Arthur L; Hitt, Kirby D; Jaffe, Fredrick F; Schurman, John R; Shen, Jianhua

    2012-09-01

    The purpose of this study was to compare results of patients with Paprosky type I and II femoral defects vs type IIIA, IIIB, and IV defects in patients undergoing revision hip arthroplasty. There were 64 patients in the group with type I and II defects with an average age of 68 years. There were 52 patients with Paprosky type IIIA, IIIB, and IV defects with an average age of 67 years. There were 8 intraoperative fractures in the type III and IV group, whereas there were 9 in the type I and II group. There were no differences between the 2 groups with respect to subsidence, loosening, dislocation, infection, and medical complications. Survivorship for the whole group was 96.9% at 5 years. Modular femoral implants provide several intraoperative options to restore leg length, offset, and stability despite femoral defects. We did not realize a higher failure rate in patients with type III or IV defects. PMID:22743124

  17. Clinical usefulness of blood metal measurements to assess the failure of metal-on-metal hip implants

    PubMed Central

    Sampson, Barry; Hart, Alister

    2012-01-01

    In April 2010, a Medicines and Healthcare Products Regulatory Agency safety alert concerning all metal-on-metal (MOM) hip replacements recommended measuring chromium and cobalt concentrations when managing patients with painful prostheses. The need for this review is illustrated by the recent surge in requests for these blood tests from orthopaedic surgeons following this alert. The aim is to provide guidance to laboratories in assessing these requests and advising clinicians on interpretation. First, we summarize the basic terminology regarding the types of hip replacements, with emphasis on the MOM type. Second, we describe the clinical concerns over implant-derived wear debris in the local tissues and distant sites. Analytical aspects of the measurement of the relevant metal ions and what factors affect the levels measured are discussed. The application of inductively coupled plasma mass spectrometry techniques to the measurement of these metals is considered in detail. The biological effects of metal wear products are summarized with local toxicity and systemic biological effects considered, including carcinogenicity, genotoxicity and systemic toxicity. Clinical cases are used to illustrate pertinent points. PMID:22155921

  18. Modular titanium alloy neck adapter failures in hip replacement - failure mode analysis and influence of implant material

    PubMed Central

    2010-01-01

    Background Modular neck adapters for hip arthroplasty stems allow the surgeon to modify CCD angle, offset and femoral anteversion intraoperatively. Fretting or crevice corrosion may lead to failure of such a modular device due to high loads or surface contamination inside the modular coupling. Unfortunately we have experienced such a failure of implants and now report our clinical experience with the failures in order to advance orthopaedic material research and joint replacement surgery. The failed neck adapters were implanted between August 2004 and November 2006 a total of about 5000 devices. After this period, the titanium neck adapters were replaced by adapters out of cobalt-chromium. Until the end of 2008 in total 1.4% (n = 68) of the implanted titanium alloy neck adapters failed with an average time of 2.0 years (0.7 to 4.0 years) postoperatively. All, but one, patients were male, their average age being 57.4 years (36 to 75 years) and the average weight 102.3 kg (75 to 130 kg). The failures of neck adapters were divided into 66% with small CCD of 130° and 60% with head lengths of L or larger. Assuming an average time to failure of 2.8 years, the cumulative failure rate was calculated with 2.4%. Methods A series of adapter failures of titanium alloy modular neck adapters in combination with a titanium alloy modular short hip stem was investigated. For patients having received this particular implant combination risk factors were identified which were associated with the occurence of implant failure. A Kaplan-Meier survival-failure-analysis was conducted. The retrieved implants were analysed using microscopic and chemical methods. Modes of failure were simulated in biomechanical tests. Comparative tests included modular neck adapters made of titanium alloy and cobalt chrome alloy material. Results Retrieval examinations and biomechanical simulation revealed that primary micromotions initiated fretting within the modular tapered neck connection. A continuous abrasion and repassivation process with a subsequent cold welding at the titanium alloy modular interface. Surface layers of 10 - 30 μm titanium oxide were observed. Surface cracks caused by fretting or fretting corrosion finally lead to fatigue fracture of the titanium alloy modular neck adapters. Neck adapters made of cobalt chrome alloy show significantly reduced micromotions especially in case of contaminated cone connection. With a cobalt-chromium neck the micromotions can be reduced by a factor of 3 compared to the titanium neck. The incidence of fretting corrosion was also substantially lower with the cobalt-chromium neck configuration. Conclusions Failure of modular titanium alloy neck adapters can be initiated by surface micromotions due to surface contamination or highly loaded implant components. In the present study, the patients at risk were men with an average weight over 100 kg. Modular cobalt chrome neck adapters provide higher safety compared to titanium alloy material. PMID:20047653

  19. Factors influencing patients' willingness to pay for new technologies in hip and knee implants.

    PubMed

    Schwarzkopf, Ran; Sagebin, Fabio M; Karia, Raj; Koenig, Karl M; Bosco, Joseph A; Slover, James D

    2013-03-01

    Rising implant prices and evolving technologies are important factors contributing to the increased cost of arthroplasty. Assessing how patients value arthroplasty, new technologies, and their perceived outcomes is critical in planning cost-effective care, as well as evaluating new-technologies. One hundred one patients undergoing arthroplasty took part in the survey. We captured demographics, spending practices, knowledge of implants, patient willingness to pay for implants, and preferences related to implant attributes. When patients were asked if they would be satisfied with "standard of care" prosthesis, 80% replied "no". When asked if they would pay for a higher than "standard of care" prosthesis, 86% replied "yes". The study demonstrated that patients, regardless of their socio-economic status, are not satisfied with standard of care implants when newer technologies are available, and they may be willing to share in the cost of their prosthesis. Patients also prefer the option to choose what they perceive to be a higher quality or innovative implant even if the "out of pocket" cost is higher. PMID:23142436

  20. A Randomised Multi-centre Study to Compare the Long-term Performance of the Future Hip to 3 Other Implants in Primary Total Hip Replacement

    ClinicalTrials.gov

    2011-09-01

    Osteoarthritis; Post-traumatic Arthritis; Collagen Disorders; Avascular Necrosis; Traumatic Femoral Fractures; Nonunion of Femoral Fractures; Congenital Hip Dysplasia; Slipped Capital Femoral Epiphysis; Perthes Disease

  1. Appraisal of evidence base for introduction of new implants in hip and knee replacement: a systematic review of five widely used device technologies

    PubMed Central

    Nieuwenhuijse, Marc J; Nelissen, R G H H; Schoones, J W

    2014-01-01

    Objective To determine the evidence of effectiveness and safety for introduction of five recent and ostensibly high value implantable devices in major joint replacement to illustrate the need for change and inform guidance on evidence based introduction of new implants into healthcare. Design Systematic review of clinical trials, comparative observational studies, and registries for comparative effectiveness and safety of five implantable device innovations. Data sources PubMed (Medline), Embase, Web of Science, Cochrane, CINAHL, reference lists of articles, annual reports of major registries, summaries of safety and effectiveness for pre-market application and mandated post-market studies at the US Food and Drug Administration. Study selection The five selected innovations comprised three in total hip replacement (ceramic-on-ceramic bearings, modular femoral necks, and uncemented monoblock cups) and two in total knee replacement (high flexion knee replacement and gender specific knee replacement). All clinical studies of primary total hip or knee replacement for symptomatic osteoarthritis in adults that compared at least one of the clinical outcomes of interest (patient centred outcomes or complications, or both) in the new implant group and control implant group were considered. Data searching, abstraction, and analysis were independently performed and confirmed by at least two authors. Quantitative data syntheses were performed when feasible. Results After assessment of 10 557 search hits, 118 studies (94 unique study cohorts) met the inclusion criteria and reported data related to 15 384 implants in 13 164 patients. Comparative evidence per device innovation varied from four low to moderate quality retrospective studies (modular femoral necks) to 56 studies of varying quality including seven high quality (randomised) studies (high flexion knee replacement). None of the five device innovations was found to improve functional or patient reported outcomes. National registries reported two to 12 year follow-up for revision occurrence related to more than 200 000 of these implants. Reported comparative data with well established alternative devices (over 1 200 000 implants) did not show improved device survival. Moreover, we found higher revision occurrence associated with modular femoral necks (hazard ratio 1.9) and ceramic-on-ceramic bearings (hazard ratio 1.0-1.6) in hip replacement and with high flexion knee implants (hazard ratio 1.0-1.8). Conclusion We did not find convincing high quality evidence supporting the use of five substantial, well known, and already implemented device innovations in orthopaedics. Moreover, existing devices may be safer to use in total hip or knee replacement. Improved regulation and professional society oversight are necessary to prevent patients from being further exposed to these and future innovations introduced without proper evidence of improved clinical efficacy and safety. PMID:25208953

  2. Implant stability in revision total hip arthroplasty: allograft bone packing following extended proximal femoral osteotomy.

    PubMed

    Chassin, E P; Silverton, C D; Berzins, A; Rosenberg, A G

    1997-12-01

    One method of revising the femoral component in revision total hip arthroplasty in the presence of compromised femoral bone stock is to pack the upper femur with particulate allograft and then to cement the femoral component into the allograft bed. This technique is being used clinically with encouraging results. Additionally, surgical exposure of the femoral canal during revision total hip arthroplasty can be greatly improved with an extended trochanteric osteotomy, which is subsequently repaired with wires or cables. To assess the feasibility of performing the allograft bone packing technique following an extended trochanteric osteotomy, the stability of this construct in a cadaver model was measured, using micromotion sensing instruments and loads applied on a materials testing machine. The stability of the cemented allograft impaction construct following extended trochanteric osteotomy was comparable to the stability of the control construct, which consisted of a similar impacted allograft construct without osteotomy. The stability of the osteotomized side was comparable to that of the control side. It is concluded that the initial in vitro stability of the allograft impaction technique following extended proximal femoral osteotomy is adequate to justify experimental in vivo use. PMID:9458251

  3. [Cemented hip prosthesis implantation--decreasing the rate of fat embolism with pulsed pressure lavage].

    PubMed

    Breusch, S J; Reitzel, T; Schneider, U; Volkmann, M; Ewerbeck, V; Lukoschek, M

    2000-06-01

    Intraoperative fat embolism associated with cemented total hip arthroplasty is a well recognized complication. In a new sheep model allowing for standardized bilateral, simultaneous cement pressurization we studied the effectiveness of both pulsatile and syringe lavage of equal volume with regard to their cleansing capabilities as measured by fat and bone marrow intravasation. The operative procedure involved bilateral placement of intravenous catheters into the external iliac veins via retroperitoneal approach. After femoral neck osteotomies both femoral cavities were prepared for retrograde cement application. After randomization one side was lavaged with 250 ml irrigation using a bladder syringe, the contralateral femur with the identical volume but using a pulsatile lavage. A specially designed apparatus was used to allow for bilateral simultaneous cement pressurization. Venous blood from both iliac catheters was then collected, anticoagulated and a quantitative and qualitative fat analysis was performed. Despite equal volume manual lavage produced significantly higher fat and bone marrow intravasation (P < 0.001) than pulsatile lavage thus suggesting that not only the volume but also the quality of bone lavage is an essential factor influencing the risk of fat embolism and adverse cardiorespiratory effects. Our findings further emphasize the important role of pulsatile lavage in preventing fat and bone marrow embolisation during cemented total hip arthroplasty. PMID:10929338

  4. Mating of a PROSTALAC spacer with an intramedullary nail for reconstruction of an infected interprosthetic femoral shaft fracture: a case report.

    PubMed

    Kamath, Atul F; Austin, Daniel; Lee, Gwo-Chin

    2012-08-01

    Reconstruction for concurrent infection of an ipsilateral total hip arthroplasty (THA) and total knee arthroplasty (TKA) is a challenge. We report a 2-stage reconstruction of a THA for chronic infection of both the THA and TKA with severe femoral bone loss secondary to interprosthetic fractures. The reconstruction involved using a custom-made, temporary, antibiotic-impregnated PROSTALAC spacer mated with an intramedullary nail. The acetabulum was then exposed and the necrotic cartilage was removed and curetted. The acetabulum was reamed to accept a PROSTALAC acetabular shell. The shell was cemented into the acetabulum with antibiotic cement. The custom-made spacer was then inserted distally first into the tibia. The distal end of the intramedullary nail was interlocked with a bicortical bolt to minimise nail rotation. Antibiotic-impregnated cement was moulded around the nail and spacer. The proximal end of the spacer was then reduced into the acetabular socket, and the joint was irrigated and the wound closed. A customised abduction brace was fitted, and partial weight bearing was allowed. Sufficient leg length, soft-tissue tension, and range of hip motion were restored, and a total femur and constrained liner was re-implanted 4 months later. Mating of an intramedullary nail with a PROSTALAC spacer is a viable reconstructive option. PMID:22933694

  5. Radiological evaluation of acetabular erosion after antibiotic-impregnated polymethylmethacrylate spacer (Spacer-G).

    PubMed

    García-Oltra, Ester; Bori, Guillem; Tomas, Xavier; Gallart, Xavier; Garcia, Sebastian; Soriano, Alex

    2013-06-01

    Different types of hip spacers have been described (hand-made, custom-molded or prefabricated) for treatment of a chronic hip infection. A potential disadvantage of monoblock prefabricated spacer is that it may cause acetabular bone loss. This study assesses the radiological acetabular erosion using an antibiotic-impregnated pre-fabricated polymethylmethacrylate Spacer-G. We retrospectively reviewed the radiographs of thirty five patients who were managed with Spacer-G to treat chronic hip infection. No acetabular erosion were observed in thirty two patients with a mean time from the first to second stage and from the first to the last radiograph of 5.09 and 3.77 months respectively. In three patients the time between the radiographs was more than one year and the second stage was not performed; two developed a protrusion acetabuli whereas the other one a destruction of the acetabular roof. Using a Spacer-G in chronic hip infection treatment for less than one year is not associated with radiological acetabular erosion if the patient is maintained at partial weight bearing. PMID:23142448

  6. Influence of the clearance on in-vitro tribology of large diameter metal-on-metal articulations pertaining to resurfacing hip implants.

    PubMed

    Rieker, Claude B; Schön, Rolf; Konrad, Reto; Liebentritt, Gernot; Gnepf, Patric; Shen, Ming; Roberts, Paul; Grigoris, Peter

    2005-04-01

    Large-diameter metal-on-metal articulations may provide an opportunity for wear reduction in total hip implants because earlier studies have shown that the formation of a fluid film that completely separates the bearing surfaces is theoretically possible. In such a lubrication mode and under ideal conditions, there is theoretically no amount of wear. Studies have suggested that the two primary parameters controlling the lubrication mode are the diameter and the clearance of the articulation. The goal of the present study was to experimentally investigate the influence of these two parameters on the wear behavior of large-diameter metal-on-metal articulations pertaining to resurfacing hip implants. The results of this in vitro investigation showed that longer running-in periods and higher amounts of running-in wear were associated with larger clearances. PMID:15833451

  7. Full-field in vitro measurements and in silico predictions of strain shielding in the implanted femur after total hip arthroplasty.

    PubMed

    Chanda, Souptick; Dickinson, Alexander; Gupta, Sanjay; Browne, Martin

    2015-08-01

    Alterations in bone strain as a result of implantation may contribute towards periprosthetic bone density changes after total hip arthroplasty. Computational models provide full-field strain predictions in implant-bone constructs; however, these predictions should be verified using experimental models wherever it is possible. In this work, finite element predictions of surface strains in intact and implanted composite femurs were verified using digital image correlation. Relationships were sought between post-implantation strain states across seven defined Gruen zones and clinically observed longer-term bone density changes. Computational predictions of strain distributions in intact and implanted femurs were compared to digital image correlation measurements in two regions of interest. Regression analyses indicated a strong linear correlation between measurements and predictions (R = 0.927 intact, 0.926 implanted) with low standard error (standard error = 38 µε intact, 26 µε implanted). Pre- to post-operative changes in measured and predicted surface strains were found to relate qualitatively to clinically observed volumetric bone density changes across seven Gruen zones: marked proximal bone density loss corresponded with a 50%-64% drop in surface strain, and slight distal density changes corresponded with 4%-14% strain increase. These results support the use of digital image correlation as a pre-clinical tool for predicting post-implantation strain shielding, indicative of long-term bone adaptations. PMID:26112349

  8. Biophysical stimulation and the periprosthetic bone: is there a rationale in the use of Pulsed Electromagnetic Fields after a hip or knee implant?

    PubMed

    Massari, L; Osti, R; Lorusso, V; Setti, S; Caruso, G

    2015-01-01

    The biophysical stimulation of bone and cartilage, using Pulsed ElectroMagnetic Fields (PEMF), covers many different aspects of bone formation and/or cartilage repair, such as healing of delayed or non-union of fracture, bone necrosis, osteocartilagineous defects. To date there are no specific data on the effects of PEMFs in osteointegration of prosthetic implants but there are some papers that denote clinical advantages, in terms of early recovery, in patients treated with these procedures. Considering these clinical applications, PEMF stimulation around hip or knee joint implants could be useful to reduce the bone oedema, pain and to reduce excessive bone reabsorption around the femoral stems. PMID:26753669

  9. Intramedullary fixation of intertrochanteric hip fractures: a comparison of two implant designs

    PubMed Central

    Efstathopoulos, Nicolas E.; Lazarettos, John T.

    2006-01-01

    We report a randomised prospective study comparing two implants, the Gamma trochanteric nail and the ACE trochanteric nail, in the treatment of intertrochanteric femoral fractures in the elderly. One hundred and twelve patients were randomised on admission into two treatment groups. Fifty-six patients were treated with Gamma nail implants, and 56 were treated with ACE trochanteric nail. The average age of these patients was 78years. Twenty fractures were stable and 92 unstable. The mean follow-up time was 8months (6 12). Regular clinical and radiological review was done 1, 3 and 6months postoperatively. Operation time, fluoroscopy time, blood transfusion and complications were recorded. The mobility score was used to assess the pre-injury and postoperative mobility status. All the patients were treated within 36h of their accident. There were no complications during surgery. All the patients were mobilised in the first 24h postoperatively, regardless of the fracture type, and weight bearing was permitted as tolerated. Union of the fracture was achieved in all patients. There was no statistically significant difference between the two groups with regard to the studied parameters. There was no mechanical failure of the implants despite the early patient mobilisation. Early operation and early mobilisation resulted in a good functional outcome in all patients. Both the trochanteric gamma nail and ACE trochanteric nail provide effective methods of treatment for intertrochanteric fractures in elderly patients. PMID:16736148

  10. Failure analysis of a total hip prosthesis implanted in active patient.

    PubMed

    Hernandez-Rodriguez, M A L; Ortega-Saenz, J A; Contreras-Hernandez, Geo R

    2010-11-01

    This work presents an analysis of a total hip prosthesis that failed in service prematurely within 5 years. The prosthesis presented a fractured stem that was extracted from a 46 year old male patient, 75 kg weight and 1.76 m height. In order to determine the origin of the failure, the femoral stem component was analyzed by means of visual inspection; optical microscope (OM), scanning electronic microscopy (SEM) and energy disperse spectroscopy (EDS). The investigation showed that the crack had originated due to a high stress concentration on the anterolateral corner section of the stem. Any discontinuity or defect on the prosthesis surface in this location acted as preferential site to nucleate a crack which propagated by fatigue until the cross section was not able to sustain an eventual high load produced for the active patient. PMID:20826368

  11. Dislocation of preformed antibiotic-loaded cement spacers (Spacer-G): etiological factors and clinical prognosis.

    PubMed

    Bori, Guillem; García-Oltra, Ester; Soriano, Alex; Rios, José; Gallart, Xavier; Garcia, Sebastian

    2014-05-01

    This study assesses the factors associated with the dislocation of the Spacer-G and its clinical prognosis. Seventy-four spacers were reviewed. Acetabular bone defects, proximal femoral cementation of the spacer and its relationship to the size of the head spacer were not associated with dislocation. The only variable that it was possible to associate with dislocation was when the previous stem, prior to the spacer placement, was a cemented stem. In patients who experienced a dislocation, infection was not cured during the interim period more frequently than patients who had not experienced a dislocation (P = 0.001) and the final clinical hip evaluation was also worse (P < 0.001). The study concludes that the surgeon should assess different surgical aspects in order to avoid mechanical complications such as dislocation and its consequences. PMID:24269066

  12. [Use of gold implants as a treatment of pain related to canine hip dysplasia--a review. Part 2: Clinical trials and case reports].

    PubMed

    Deisenroth, A; Nolte, I; Wefstaedt, P

    2013-01-01

    Gold bead implantation/gold acupuncture is becoming increasingly used in veterinary medicine as a method of pain treatment in cases of osteoarthritic diseases. Part one of the overview dealing with the use of gold implants as a treatment of canine hip joint dysplasia (cHD) introduced the method of implanting gold in tissue and publications which investigated the subsequent effects of implantation. This article focuses on publications concerning the clinical effectiveness of gold implantation within the scope of pain therapy in cHD. Due to the study design, a classification using evidence-based levels (EbL) was carried out. Three double-blind, placebo-controlled randomised studies (EbL II) were considered together with three retrospective studies on own patients (EbL IV) and five case studies (EbL IV). While the case and retrospective studies reported impressive therapeutic success in treating cHD-incurred pain with gold implantation, a pain-reducing effect through gold implantation was only demonstrated in one of the three double-blind studies. The two remaining EbL II studies found no differences between the placebo-group and the group of dogs treated with gold implantation. In one of these two studies, kinematic and kinetic gait analyses were used for objective evaluation of the effects of the treatment. Thus, the only study that carried out an objective evaluation of the therapeutic result of gold implantation came to the conclusion that the method is ineffective. For a concluding assessment of gold implantation in the case of cHD, gait analysis studies investigating the effects of gold implantation in comparison to a standard treatment with nonsteroidal anti-inflammatory drugs are currently lacking. PMID:23958708

  13. The effect of microstructure on the wear of cobalt-based alloys used in metal-on-metal hip implants.

    PubMed

    Varano, R; Bobyn, J D; Medley, J B; Yue, S

    2006-02-01

    The influence of microstructure on the wear of cobalt-based alloys used in metal-on-metal hip implants was investigated in a boundary lubrication regime designed to represent the conditions that occurred some of the time in vivo. These cobalt-chromium-molybdenum alloys were either wrought, with a total carbon content of 0.05 or 0.23 wt %, cast with a solution-annealing procedure or simply as-cast but not solution annealed. Bars of these different alloy grades were subjected to various heat treatments to develop different microstructures. The wear was evaluated in a linear-tracking reciprocating pin-on-plate apparatus with a 25 per cent bovine serum lubricant. The wear was found to be strongly affected by the dissolved carbon content of the alloys and mostly independent of grain size or the carbide characteristics. The increased carbon in solid solution caused reductions in volumetric wear because carbon helped to stabilize a face-centred cubic crystal structure, thus limiting the amount of strain-induced transformation to a hexagonal close-packed crystal structure. Based on the observed surface twining in and around the contact zone and the potentially detrimental effect of the hexagonal close-packed phase, it was postulated that the wear of cobalt-based alloys in the present study was controlled by a deformation mechanism. PMID:16669383

  14. Hip pain and pseudo-lengthening of the leg due to iliopsoas haematoma following implantation of an uncemented component in acetabular cotyloplasty technique.

    PubMed

    Apostolopoulos, Alexandros P; Sidaginamale, Raghavendra Prasad; McConnell, B; Manta, A; Zafiropoulos, G

    2012-01-01

    We report early symptomatic (groin pain and apparent limb lengthening) findings in our 12 consecutive patients who underwent total hip replacements using a cementless acetabular cotyloplasty technique. This report is the first in the literature to mention such an early complication in a large number of patients and also to describe early detection and treatment in these cases. During the period of January 2007 to December 2010, 12 patients (seven female, five male) with dysplastic hip underwent total hip arthroplasty. The mean age of the patients was 57 years (range 52-61 years) and the mean follow-up time was 18 months (12-36 months). A cotyloplasty technique was performed and uncemented acetabular and femoral components were implanted in all these 12 patients. All patients were reviewed postoperatively for clinical and radiographic assessment at six weeks, three months, six months, and one year, and then annually thereafter. During the first one to two months (mean time 22 ± 16 days), all patients complained of a constant pain in the groin that started in the early postoperative period. A pseudo lengthening of the operated hip and pelvic tilt was found on clinical examination at the three-month follow-up. The True length did not reveal a significant leg length discrepancy. Hip pain, pseudo lengthening, and pelvic tilt resolved within 123 ± 17 days post-op. A cotyloplasty technique using an uncemented acetabular implant can cause an intrapelvic hematoma of the iliopsoas muscle giving rise to temporary groin pain, pseudo lengthening on the operated side, and gait disturbances to the patient in the early postoperative period. Symptoms resolved completely in all of our cases. Iliopsoas physiotherapy could be useful and should be encouraged during the symptomatic period. Patients have to be informed during consenting and reassured about this symptomatology. Awareness of this likely complication would help surgeons to detect the problem and initiate treatment early. PMID:23662658

  15. Arthroscopic Fixation of Cell Free Polymer-Based Cartilage Implants with a Bioinspired Polymer Surface on the Hip Joint: A Cadaveric Pilot Study

    PubMed Central

    Lahner, Matthias; Duif, Christian; Ficklscherer, Andreas; Kaps, Christian; Kalwa, Lukas; Seidl, Tobias

    2014-01-01

    This study investigates the adhesion capacity of a polyglycolic acid- (PGA-) hyaluronan scaffold with a structural modification based on a planar polymer (PM) surface in a cadaver cartilage defect model. Two cadaver specimens were used to serially test multiple chondral matrices. In a cadaver hip model, cell free polymer-based cartilage implants with a planar bioinspired PM surface (PGA-PM-scaffolds) were implanted arthroscopically on 10?mm??15?mm full-thickness femoral hip cartilage lesions. Unprocessed cartilage implants without a bioinspired PM surface were used as control group. The cartilage implants were fixed without and with the use of fibrin glue on femoral hip cartilage defects. After 50 movement cycles and removal of the distraction, a rearthroscopy was performed to assess the outline attachment and integrity of the scaffold. The fixation techniques without and with fibrin fixation showed marginal differences for outline attachment, area coverage, scaffold integrity, and endpoint fixation after 50 cycles. The PGA-PM-scaffolds with fibrin fixation achieved a higher score in terms of the attachment, integrity, and endpoint fixation than the PGA-scaffold on the cartilage defect. Relating to the outline attachment, area coverage, scaffold integrity, and endpoint fixation, the fixation with PGA-PM-scaffolds accomplished significantly better results compared to the PGA-scaffolds (P = 0.03752, P = 0.03078, P = 0.00512, P = 0.00512). PGA-PM-scaffolds demonstrate increased observed initial fixation strength in cadaver femoral head defects relative to PGA-scaffold, particularly when fibrin glue is used for fixation. PMID:25247185

  16. Two years follow-up study of the pain-relieving effect of gold bead implantation in dogs with hip-joint arthritis.

    PubMed

    Jaeger, Gry T; Larsen, Stig; Søli, Nils; Moe, Lars

    2007-01-01

    Seventy-eight dogs with pain from hip dysplasia participated in a six-month placebo-controlled, double-blinded clinical trial of gold bead implantation. In the present, non-blinded study, 73 of these dogs were followed for an additional 18 months to evaluate the long-term pain-relieving effect of gold bead implantation. The recently-published results of the six month period revealed that 30 of the 36 dogs (83%) in the gold implantation group showed significant improvement (p = 0.02), included improved mobility and reduction in the signs of pain, compared to the placebo group (60% improvement). In the long-term two-year follow-up study, 66 of the 73 dogs had gold implantation and seven dogs continued as a control group. The 32 dogs in the original placebo group had gold beads implanted and were followed for a further 18 months. A certified veterinary acupuncturist used the same procedure to insert the gold beads as in the blinded study, and the owners completed the same type of detailed questionnaires. As in the blinded study, one investigator was responsible for all the assessments of each dog. The present study revealed that the pain-relieving effect of gold bead implantation observed in the blinded study continued throughout the two-year follow-up period. PMID:17381835

  17. Survivorship of Hip and Knee Implants in Pediatric and Young Adult Populations

    PubMed Central

    Sedrakyan, Art; Romero, Lucas; Graves, Stephen; Davidson, David; de Steiger, Richard; Lewis, Peter; Solomon, Michael; Vial, Robyn; Lorimer, Michelle

    2014-01-01

    Background: One of the least researched areas in orthopaedic pediatrics is the safety and effectiveness of joint replacement, in part because it is uncommon and is undertaken for a wide range of conditions not common for adult joint replacement. This study used data from the AOANJRR (Australian Orthopaedic Association National Joint Replacement Registry) to analyze the use of total hip arthroplasty (THA) and total knee arthroplasty (TKA) in the pediatric population and to provide preliminary data on the outcome of these procedures. Methods: The AOANJRR, which is part of the ICOR (International Consortium of Orthopaedic Registries), provided information on pediatric procedures reported to the registry by hospitals undertaking arthroplasty procedures in Australia. All THA and TKA procedures reported to the registry from 1999 to 2012 were included. The cumulative percent revision and the hazard ratio from Cox proportional-hazards models were used for analysis. All tests were two-tailed, with a 5% level of significance. Additionally, an overview of the literature is presented to provide a point of reference. Results: Primary conventional THA was performed in 297 patients twenty years of age or younger; the cumulative percent revision at five years was 4.5%. Primary conventional THA was performed in 975 young adults twenty-one to thirty years of age; the cumulative percent revision at five years was 5.4%. Primary THA was performed in 105 patients twenty years of age or younger; the cumulative percent revision at five years was 4.6%. Primary TKA was performed in 159 young adults twenty-one to thirty years of age; the cumulative percent revision at five years was 10.3%. Conclusions: Compared with older adults, pediatric patients and young adults undergoing THA and TKA have very different diagnoses, including a high prevalence of tumor. Although the reported rate of revision surgery is currently similar to that for older patients, the number of reported procedures and the follow-up period remain limited. It is important for registries to continue to collect and analyze data relevant to this cohort and to coordinate these activities in order to better understand the safety and effectiveness of joint arthroplasty in the pediatric population. PMID:25520422

  18. Metal Ion Concentrations in Body Fluids after Implantation of Hip Replacements with Metal-on-Metal Bearing – Systematic Review of Clinical and Epidemiological Studies

    PubMed Central

    Hartmann, Albrecht; Hannemann, Franziska; Lützner, Jörg; Seidler, Andreas; Drexler, Hans; Günther, Klaus-Peter; Schmitt, Jochen

    2013-01-01

    Introduction The use of metal-on-metal (MoM) total hip arthroplasty (THA) increased in the last decades. A release of metal products (i.e. particles, ions, metallo-organic compounds) in these implants may cause local and/or systemic adverse reactions. Metal ion concentrations in body fluids are surrogate measures of metal exposure. Objective To systematically summarize and critically appraise published studies concerning metal ion concentrations after MoM THA. Methods Systematic review of clinical trials (RCTs) and epidemiological studies with assessment of metal ion levels (cobalt, chromium, titanium, nickel, molybdenum) in body fluids after implantation of metalliferous hip replacements. Systematic search in PubMed and Embase in January 2012 supplemented by hand search. Standardized abstraction of pre- and postoperative metal ion concentrations stratified by type of bearing (primary explanatory factor), patient characteristics as well as study quality characteristics (secondary explanatory factors). Results Overall, 104 studies (11 RCTs, 93 epidemiological studies) totaling 9.957 patients with measurement of metal ions in body fluids were identified and analyzed. Consistently, median metal ion concentrations were persistently elevated after implantation of MoM-bearings in all investigated mediums (whole blood, serum, plasma, erythrocytes, urine) irrespective of patient characteristics and study characteristics. In several studies very high serum cobalt concentrations above 50 µg/L were measured (detection limit typically 0.3 µg/L). Highest metal ion concentrations were observed after treatment with stemmed large-head MoM-implants and hip resurfacing arthroplasty. Discussion Due to the risk of local and systemic accumulation of metallic products after treatment with MoM-bearing, risk and benefits should be carefully balanced preoperatively. The authors support a proposed „time out“ for stemmed large-head MoM-THA and recommend a restricted indication for hip resurfacing arthroplasty. Patients with implanted MoM-bearing should receive regular and standardized monitoring of metal ion concentrations. Further research is indicated especially with regard to potential systemic reactions due to accumulation of metal products. PMID:23950923

  19. Endoscopy of the femoral canal in revision arthroplasty of the hip.A new method for improving the operative technique and analysis of implant failure.

    PubMed

    Köster, G; Willert, H; Buchhorn, G H

    1999-01-01

    Femoral endoscopy using a special endoscope was performed in 28 revision arthroplasties with the aim of improving the operative technique and to analyze implant failure. Before clinical application, the method was used to analyze the implant bed in clinically and radiographically well-fixed prostheses in autopsy cases without implant failure. Initially, it was performed on 4 experimental implantations of newly designed revision devices into cadaver femurs to obtain additional information concerning the design rationale of implants and instruments for revision surgery. During revision surgery, the new endoscope showed that controlled removal of the cement and granulomatous tissue was possible while avoiding cortical windows or transfemoral approaches. Under visual control, preparation of the new implant bed was less hazardous and more efficient, resulting in good preservation of bone stock and reduced exposure to X-rays. Analysis of the implant bed in failed hip endoprostheses revealed cracks or fractures of the cement mantle in 21 of 23 cemented components. There were two different types of cracks: longitudinal and transverse, which were mostly connected and invisible to X-ray analysis. Cement defects, thin cement mantles, or the proximal border of the cement mantle were found to be places where cracks originated. Granulomatous tissue was noted to protrude into the cement fissures and cracks. In autopsy cases, cement cracks were also found in clinically asymptomatic and radiographically well-fixed prostheses. These cracks were observed to be mainly oriented in the longitudinal direction, similar to those seen in the revision cases. Early signs of debonding became obvious even without lesions in the cement mantle. In experimental implantations of newly designed stems, the efficacy of the different instruments and the fit of the implant could be evaluated by endoscopic control inside the intramedullary canal. Further, it was possible to directly visualize the shape and condition of the primary implant bed after removal of the implant. Femoral endoscopy improved the surgical technique in revision arthroplasty. In addition, it is a very useful tool for the analysis of the implant bed in clinical and autopsy cases as well as in experimental implantations. PMID:10447616

  20. A simple fully integrated contact-coupled wear prediction for ultra-high molecular weight polyethylene hip implants.

    PubMed

    Kang, L; Galvin, A L; Jin, Z M; Fisher, J

    2006-01-01

    A fully coupled contact and wear model was developed in the present study for hip implants employing an ultra-high molecular weight polyethylene (UHMWPE) cup in combination with a metallic or ceramic femoral head. A simple elasticity equation based on the concept of constrained column model was employed to solve the contact mechanics between the acetabular cup and the femoral head under the three-dimensional physiological loading condition. The wear model was based on the classical Archard-Lancaster equation in common with all other studies reported in the literature. The fully coupled contact and wear model was applied to both conventional and cross-linked UHMWPE cups under a wide range of design parameters such as the clearance and the femoral head radius. The predicted linear and volumetric wear as well as their rates for conventional UHMWPE cups were found to be in good agreement with those obtained from a similar analysis by Maxian but using the finite element method for the contact mechanics analysis. The predicted maximum contact pressure was found to decrease rapidly within the first 10(6) cycles, and below the limit to cause plastic deformation within the UHMWPE cup with a nominal radial clearance of 0.2 mm. The effect of the clearance between the head and the cup on the predicted wear was found to be negligible. For the cross-linked UHMWPE cup with relatively large diameters up to 48 mm and a fixed outside diameter of 50 mm, the predicted wear, which was found to increase with increasing femoral head radius, remained small owing to the small wear factor associated with these materials. Furthermore, if the head diameter increases beyond 42 mm, a rapid increase in the contact pressure was predicted, owing to the decrease in the wall thickness of the cross-linked UHMWPE cup. PMID:16459444

  1. Radiographic identification of loose bodies in the traumatized hip joint

    SciTech Connect

    Baird, R.A.; Schobert, W.E.; Pais, M.J.; Ahmed, M.; Wilson, W.J.; Farjalla, G.L.; Imray, T.J.

    1982-12-01

    Acrylic spacers and cubes of cortical bone of known dimensions were placed in predetermined locations in cadaver hip joints, which were then studied with plain radiography and linear, hypocycloidal, and computed tomography (CT). Joint space widening was not measurable on plain radiographs of the pelvis when 2-mm spacers were placed anywhere within the hip joint. When 4-mm spacers were used, widening measured 2 mm in the axis of measurement corresponding to the location of the spacer. Linear tomography did not permit identification of the 2-mm cubes; however, hypocycloidal tomography and CT consistently showed them anywhere within the hip joint. Radiation dose and clinical recommendations are discussed.

  2. Minimally invasive total hip arthroplasty.

    PubMed

    Hohler, Sharon E

    2004-06-01

    Total hip arthroplasty procedures relieve patients' arthritic hip pain. Since the first procedure was performed in the 1960s, surgeons and implant companies have worked to improve prosthesis design, composition of implants, and the mechanisms for holding the implants in place. Recently, surgeons have focused on minimizing the surgical incision. Smaller incisions have resulted in smaller scars and faster recoveries. This article presents a brief historical overview of, as well as current trends in, minimally invasive total hip arthroplasty. All aspects of care for a patient undergoing total hip arthroplasty are discussed. PMID:15239326

  3. Hip Implant Systems

    MedlinePlus

    ... of metal and the socket is made of plastic (polyethylene) or has a plastic lining. Ceramic-on-Polyethylene: The ball is made of ceramic and the socket is made of plastic (polyethylene) or has a plastic lining. Metal-on- ...

  4. First insight on the impact of an osteoblastic layer on the bio-tribocorrosion performance of Ti6Al4V hip implants.

    PubMed

    Runa, M J; Mathew, M T; Fernandes, M H; Rocha, L A

    2015-01-01

    In uncemented Ti6Al4V hip implants, the bone-stem interface is subjected to cyclic loading motion driven by the daily activities of the patients, which may lead to the complete failure of the implant in the long term. It may also compromise the proliferation and differentiation processes of osteoblastic cells (bone-forming cells). The main objective of this work is to approach for the first time the role of these organic materials on the bio-tribocorrosion mechanisms of cultured Ti6Al4V alloys. The colonized materials with MG63 osteoblastic-like cells were characterized through cell viability/proliferation and enzymatic activity. Tribocorrosion tests were performed under a reciprocating sliding configuration and low contact pressure. Electrochemical techniques were used to measure the corrosion kinetics of the system, under free potential conditions. All tests were performed at a controlled atmosphere. The morphology and topography of the wear scar were evaluated. The results showed that the presence of an osteoblastic cell layer on the implant surface significantly influences the tribocorrosion behavior of Ti6Al4V alloy. It was concluded that the cellular material was able to form an extra protective layer that inhibits further wear degradation of the alloy and decreases its corrosion tendency. PMID:25448346

  5. Mechanical implications of interfacial defects between femoral hip implants and cement: a finite element analysis of interfacial gaps and interfacial porosity.

    PubMed

    Scheerlinck, T; Broos, J; Janssen, D; Verdonschot, N

    2008-10-01

    Two types of defect between femoral hip implants and cement have been identified. Interfacial porosity arises from cement shrinkage during curing and presents as pores randomly located along the stem. Interfacial gaps are much larger stem-cement separations caused by air introduced during stem insertion. To investigate the mechanical consequences of both types of defect, a finite element analysis model was created on the basis of a computed tomography image of a Charnley-Kerboul stem, and alternating torsional and transverse loads were applied. The propagation of fatigue cracks within the cement and the rotational stability of the stem were assessed in models simulating increasing amounts of interfacial gaps and pores. Anterior gaps covering at least 30 per cent of the implant surface promoted cement cracks and destabilized the stem. Anterolateral gaps were less destabilizing, but had more potential to promote cracks. In both cases, cracks occurred mainly outside gap regions, in areas where the stem contacted the cement during cyclic loading. Although random interfacial pores did not destabilize the implant, they acted as crack initiators even at low fractions (10 per cent). In conclusion, random interfacial pores were more harmful for the cement mantle integrity than were larger regions of interfacial gaps, although gaps were more detrimental for the rotational stability of the stem. PMID:19024152

  6. Metal-on-Metal Hip Prostheses and Systemic Health: A Cross-Sectional Association Study 8 Years after Implantation

    PubMed Central

    Prentice, Jennifer R.; Clark, Matthew J.; Hoggard, Nigel; Morton, Allison C.; Tooth, Claire; Paley, Martyn N.; Stockley, Ian; Hadjivassiliou, Marios; Wilkinson, J. Mark

    2013-01-01

    There is public concern over the long term systemic health effects of metal released from hip replacement prostheses that use large-diameter metal-on-metal bearings. However, to date there has been no systematic study to determine which organs may be at risk, or the magnitude of any effect. We undertook a detailed cross-sectional health screen at a mean of 8 years after surgery in 35 asymptomatic patients who had previously received a metal-on-metal hip resurfacing (MoMHR) versus 35 individually age and sex matched asymptomatic patients who had received a conventional hip replacement. Total body bone mineral density was 5% higher (mean difference 0.05 g/cm2, P = 0.02) and bone turnover was 14% lower (TRAP 5b, mean difference −0.56IU/L, P = 0.006; osteocalcin, mean difference −3.08 ng/mL, P = 0.03) in the hip resurfacing versus conventional hip replacement group. Cardiac ejection fraction was 7% lower (mean absolute difference −5%, P = 0.04) and left ventricular end-diastolic diameter was 6% larger (mean difference 2.7 mm, P = 0.007) in the hip resurfacing group versus those patients who received a conventional hip replacement. The urinary fractional excretion of metal was low (cobalt 5%, chromium 1.5%) in patients with MoMHR, but creatinine clearance was normal. Diuretic prescription was associated with a 40% increase in the fractional excretion of chromium (mean difference 0.5%, P = 0.03). There was no evidence of difference in neuropsychological, renal tubular, hepatic or endocrine function between groups (P>0.05). Our findings of differences in bone and cardiac function between patient groups suggest that chronic exposure to low elevated metal concentrations in patients with well-functioning MoMHR prostheses may have systemic effects. Long-term epidemiological studies in patients with well-functioning metal on metal hip prostheses should include musculoskeletal and cardiac endpoints to quantitate the risk of clinical disease. PMID:23762480

  7. 21 CFR 888.3370 - Hip joint (hemi-hip) acetabular metal cemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... prosthesis. 888.3370 Section 888.3370 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... (hemi-hip) acetabular metal cemented prosthesis. (a) Identification. A hip joint (hemi-hip) acetabular metal cemented prosthesis is a device intended to be implanted to replace a portion of the hip...

  8. 21 CFR 888.3400 - Hip joint femoral (hemi-hip) metallic resurfacing prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... prosthesis. 888.3400 Section 888.3400 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... femoral (hemi-hip) metallic resurfacing prosthesis. (a) Identification. A hip joint femoral (hemi-hip) metallic resurfacing prosthesis is a device intended to be implanted to replace a portion of the hip...

  9. 21 CFR 888.3370 - Hip joint (hemi-hip) acetabular metal cemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... prosthesis. 888.3370 Section 888.3370 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... (hemi-hip) acetabular metal cemented prosthesis. (a) Identification. A hip joint (hemi-hip) acetabular metal cemented prosthesis is a device intended to be implanted to replace a portion of the hip...

  10. 21 CFR 888.3400 - Hip joint femoral (hemi-hip) metallic resurfacing prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... prosthesis. 888.3400 Section 888.3400 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... femoral (hemi-hip) metallic resurfacing prosthesis. (a) Identification. A hip joint femoral (hemi-hip) metallic resurfacing prosthesis is a device intended to be implanted to replace a portion of the hip...

  11. 21 CFR 888.3370 - Hip joint (hemi-hip) acetabular metal cemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... prosthesis. 888.3370 Section 888.3370 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... (hemi-hip) acetabular metal cemented prosthesis. (a) Identification. A hip joint (hemi-hip) acetabular metal cemented prosthesis is a device intended to be implanted to replace a portion of the hip...

  12. 21 CFR 888.3400 - Hip joint femoral (hemi-hip) metallic resurfacing prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... prosthesis. 888.3400 Section 888.3400 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... femoral (hemi-hip) metallic resurfacing prosthesis. (a) Identification. A hip joint femoral (hemi-hip) metallic resurfacing prosthesis is a device intended to be implanted to replace a portion of the hip...

  13. Validation of primary metal-on-metal hip arthroplasties on the National Joint Registry for England, Wales and Northern Ireland using data from the London Implant Retrieval Centre

    PubMed Central

    Sabah, S. A.; Henckel, J.; Cook, E.; Whittaker, R.; Hothi, H.; Pappas, Y.; Blunn, G.; Skinner, J. A.; Hart, A. J.

    2015-01-01

    Arthroplasty registries are important for the surveillance of joint replacements and the evaluation of outcome. Independent validation of registry data ensures high quality. The ability for orthopaedic implant retrieval centres to validate registry data is not known. We analysed data from the National Joint Registry for England, Wales and Northern Ireland (NJR) for primary metal-on-metal hip arthroplasties performed between 2003 and 2013. Records were linked to the London Implant Retrieval Centre (RC) for validation. A total of 67045 procedures on the NJR and 782 revised pairs of components from the RC were included. We were able to link 476 procedures (60.9%) recorded with the RC to the NJR successfully. However, 306 procedures (39.1%) could not be linked. The outcome recorded by the NJR (as either revised, unrevised or death) for a primary procedure was incorrect in 79 linked cases (16.6%). The rate of registry-retrieval linkage and correct assignment of outcome code improved over time. The rates of error for component reference numbers on the NJR were as follows: femoral head category number 14/229 (5.0%); femoral head batch number 13/232 (5.3%); acetabular component category number 2/293 (0.7%) and acetabular component batch number 24/347 (6.5%). Registry-retrieval linkage provided a novel means for the validation of data, particularly for component fields. This study suggests that NJR reports may underestimate rates of revision for many types of metal-on-metal hip replacement. This is topical given the increasing scope for NJR data. We recommend a system for continuous independent evaluation of the quality and validity of NJR data. Cite this article: Bone Joint J 2015;97-B:1018. PMID:25568407

  14. Autoclaved metal-on-cement spacer versus static spacer in two-stage revision in periprosthetic knee infection

    PubMed Central

    Chen, Yu-Pin; Wu, Cheng-Chun; Ho, Wei-Pin

    2016-01-01

    Background: Periprosthetic knee infection is troublesome for Orthopedic surgeons and a catastrophy for patients. Reported rates of periprosthetic joint infection following primary total knee arthroplasty (TKA) are 0.39–2%. Two stage revision arthroplasty, which has success rates exceeding 90%, has been the gold standard for treating subacute and chronic periprosthetic infection following TKA. Antibiotic spacers, a well established means of delivering local antibiotic therapy, maintain soft tissue tension during two stage revision arthroplasty. However, controversy remains around whether static or mobile antibiotic impregnated spacers are superior for treating infection following TKA. Various mobile spacers are available, including cement-on-cement, cement-on-polyethylene and metal-on-polyethylene. In this study, the efficacy of the modified metal-on-cement spacer, consisting of reinsertion of the autoclaved femoral component and implantation of antibiotic-loaded cement in the proximal tibia, is assessed. Materials and Methods: Records of 19 patients diagnosed as periprosthetic knee infection were reviewed in this retrospective study. Among these patients, 10 patients received first stage debridement with the autoclaved metal-on-cement spacer and 8 patients with the static spacer, who eventually underwent two-stage re-implantation, were listed in the final comparison. Patient demographics, infection eradication rates, average range of motion (ROM), surgical time and blood loss during the second-stage of the surgery, and Knee Society (KS) knee scores at last followup after revision total knee replacement were clinically evaluated. Results: At a minimum of 2-year followup after re-implantation, infection eradication rates, surgical times, blood loss during the second-stage of the surgery, and KS knee score after re-implantation were similar for the two groups. Patients receiving autoclaved metal-on-cement spacers had superior ROM after re-implantation compared to that of patients with static spacers. Conclusions: The autoclaved metal-on-cement spacer is an effective and simple method for two-stage re-implantation of a periprosthetic knee infection. Through this spacer, the good interim ROM can be achieved without the additional cost of prefabricated molds or new polyethylene tibial inserts. In addition, ROM after re-implantation is better than that with static spacers. PMID:27053803

  15. Preliminary Results of Implantation in Animal Model and Osteoblast Culture Evaluation of Prototypes of Biomimetic Multispiked Connecting Scaffold for Noncemented Stemless Resurfacing Hip Arthroplasty Endoprostheses

    PubMed Central

    Uklejewski, Ryszard; Rogala, Piotr; Winiecki, Mariusz; Kędzia, Andrzej; Ruszkowski, Piotr

    2013-01-01

    We present the new fixation method for RHA (resurfacing hip arthroplasty) endoprostheses by means of the biomimetic multispiked connecting scaffold (MSC-Scaffold). Such connecting scaffold can generate new type of RHA endoprostheses, that is stemless and fixed entirely without cement. The preprototypes of this MSC-Scaffold were manufactured with modern additive laser additive technology (SLM). The pilot surgical implantations in animal model (two laboratory swine) of MSC-Scaffold preprototypes have showed after two months neither implant loosening, migration, and nor other early complications. From the results of performed histopathological evaluation of the periscaffold spikes bone tissue and 10-day culture of human osteoblasts (NHOst) we can conclude that (1) the scaffolding effect was obtained and (2) to improve the osseointegration of the scaffold spikes, their material surface should be physicochemically modified (e.g., with hydroxyapatite). Some histopathological findings in the periscaffold domain near the MSC-Scaffold spikes bases (fibrous connective tissue and metallic particles near the MSC-Scaffold spikes bases edges) prompt considering the necessity to optimize the design of the MSC-Scaffold in the regions of its interspike space near the spikes bases edges, to provide more room for new bone formation in this region and for indispensable post-processing (glass pearl blasting) after the SLM manufacturing. PMID:23984397

  16. Preliminary results of implantation in animal model and osteoblast culture evaluation of prototypes of biomimetic multispiked connecting scaffold for noncemented stemless resurfacing hip arthroplasty endoprostheses.

    PubMed

    Uklejewski, Ryszard; Rogala, Piotr; Winiecki, Mariusz; K?dzia, Andrzej; Ruszkowski, Piotr

    2013-01-01

    We present the new fixation method for RHA (resurfacing hip arthroplasty) endoprostheses by means of the biomimetic multispiked connecting scaffold (MSC-Scaffold). Such connecting scaffold can generate new type of RHA endoprostheses, that is stemless and fixed entirely without cement. The preprototypes of this MSC-Scaffold were manufactured with modern additive laser additive technology (SLM). The pilot surgical implantations in animal model (two laboratory swine) of MSC-Scaffold preprototypes have showed after two months neither implant loosening, migration, and nor other early complications. From the results of performed histopathological evaluation of the periscaffold spikes bone tissue and 10-day culture of human osteoblasts (NHOst) we can conclude that (1) the scaffolding effect was obtained and (2) to improve the osseointegration of the scaffold spikes, their material surface should be physicochemically modified (e.g., with hydroxyapatite). Some histopathological findings in the periscaffold domain near the MSC-Scaffold spikes bases (fibrous connective tissue and metallic particles near the MSC-Scaffold spikes bases edges) prompt considering the necessity to optimize the design of the MSC-Scaffold in the regions of its interspike space near the spikes bases edges, to provide more room for new bone formation in this region and for indispensable post-processing (glass pearl blasting) after the SLM manufacturing. PMID:23984397

  17. Multi-Disciplinary Antimicrobial Strategies for Improving Orthopaedic Implants to Prevent Prosthetic Joint Infections in Hip and Knee

    PubMed Central

    Getzlaf, Matthew A.; Lewallen, Eric A.; Kremers, Hilal M.; Jones, Dakota L.; Bonin, Carolina A.; Dudakovic, Amel; Thaler, Roman; Cohen, Robert C.; Lewallen, David G.; van Wijnen, Andre J.

    2016-01-01

    Like any foreign object, orthopaedic implants are susceptible to infection when introduced into the human body. Without additional preventative measures, the absolute number of annual prosthetic joint infections will continue to rise, and may exceed the capacity of health care systems in the near future. Bacteria are difficult to eradicate from synovial joints due to their exceptionally diverse taxonomy, complex mechanistic attachment capabilities, and tendency to evolve antibiotic resistance. When a primary orthopaedic implant fails from prosthetic joint infection, surgeons are generally challenged by limited options for intervention. In this review, we highlight the etiology and taxonomic groupings of bacteria known to cause prosthetic joint infections, and examine their key mechanisms of attachment. We propose that antimicrobial strategies should focus on the most harmful bacteria taxa within the context of occurrence, taxonomic diversity, adhesion mechanisms, and implant design. Patient-specific identification of organisms that cause prosthetic joint infections will permit assessment of their biological vulnerabilities. The latter can be targeted using a range of antimicrobial techniques that exploit different colonization mechanisms including implant surface attachment, biofilm formation, and/or hematogenous recruitment. We anticipate that customized strategies for each patient, joint, and prosthetic component will be most effective at reducing prosthetic joint infections, including those caused by antibiotic-resistant and polymicrobial bacteria. PMID:26449208

  18. Multi-disciplinary antimicrobial strategies for improving orthopaedic implants to prevent prosthetic joint infections in hip and knee.

    PubMed

    Getzlaf, Matthew A; Lewallen, Eric A; Kremers, Hilal M; Jones, Dakota L; Bonin, Carolina A; Dudakovic, Amel; Thaler, Roman; Cohen, Robert C; Lewallen, David G; van Wijnen, Andre J

    2016-02-01

    Like any foreign object, orthopaedic implants are susceptible to infection when introduced into the human body. Without additional preventative measures, the absolute number of annual prosthetic joint infections will continue to rise, and may exceed the capacity of health care systems in the near future. Bacteria are difficult to eradicate from synovial joints due to their exceptionally diverse taxonomy, complex mechanistic attachment capabilities, and tendency to evolve antibiotic resistance. When a primary orthopaedic implant fails from prosthetic joint infection, surgeons are generally challenged by limited options for intervention. In this review, we highlight the etiology and taxonomic groupings of bacteria known to cause prosthetic joint infections, and examine their key mechanisms of attachment. We propose that antimicrobial strategies should focus on the most harmful bacteria taxa within the context of occurrence, taxonomic diversity, adhesion mechanisms, and implant design. Patient-specific identification of organisms that cause prosthetic joint infections will permit assessment of their biological vulnerabilities. The latter can be targeted using a range of antimicrobial techniques that exploit different colonization mechanisms including implant surface attachment, biofilm formation, and/or hematogenous recruitment. We anticipate that customized strategies for each patient, joint, and prosthetic component will be most effective at reducing prosthetic joint infections, including those caused by antibiotic-resistant and polymicrobial bacteria. 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:177-186, 2016. PMID:26449208

  19. Wear particles derived from metal hip implants induce the generation of multinucleated giant cells in a 3-dimensional peripheral tissue-equivalent model.

    PubMed

    Dutta, Debargh K; Potnis, Pushya A; Rhodes, Kelly; Wood, Steven C

    2015-01-01

    Multinucleate giant cells (MGCs) are formed by the fusion of 5 to 15 monocytes or macrophages. MGCs can be generated by hip implants at the site where the metal surface of the device is in close contact with tissue. MGCs play a critical role in the inflammatory processes associated with adverse events such as aseptic loosening of the prosthetic joints and bone degeneration process called osteolysis. Upon interaction with metal wear particles, endothelial cells upregulate pro-inflammatory cytokines and other factors that enhance a localized immune response. However, the role of endothelial cells in the generation of MGCs has not been completely investigated. We developed a three-dimensional peripheral tissue-equivalent model (PTE) consisting of collagen gel, supporting a monolayer of endothelial cells and human peripheral blood mononuclear cells (PBMCs) on top, which mimics peripheral tissue under normal physiological conditions. The cultures were incubated for 14 days with Cobalt chromium alloy (CoCr ASTM F75, 1-5 micron) wear particles. PBMC were allowed to transit the endothelium and harvested cells were analyzed for MGC generation via flow cytometry. An increase in forward scatter (cell size) and in the propidium iodide (PI) uptake (DNA intercalating dye) was used to identify MGCs. Our results show that endothelial cells induce the generation of MGCs to a level 4 fold higher in 3-dimentional PTE system as compared to traditional 2-dimensional culture plates. Further characterization of MGCs showed upregulated expression of tartrate resistant alkaline phosphatase (TRAP) and dendritic cell specific transmembrane protein, (DC-STAMP), which are markers of bone degrading cells called osteoclasts. In sum, we have established a robust and relevant model to examine MGC and osteoclast formation in a tissue like environment using flow cytometry and RT-PCR. With endothelial cells help, we observed a consistent generation of metal wear particle- induced MGCs, which heralds metal on metal hip failures. PMID:25894745

  20. Wear Particles Derived from Metal Hip Implants Induce the Generation of Multinucleated Giant Cells in a 3-Dimensional Peripheral Tissue-Equivalent Model

    PubMed Central

    Dutta, Debargh K.; Potnis, Pushya A.; Rhodes, Kelly; Wood, Steven C.

    2015-01-01

    Multinucleate giant cells (MGCs) are formed by the fusion of 5 to 15 monocytes or macrophages. MGCs can be generated by hip implants at the site where the metal surface of the device is in close contact with tissue. MGCs play a critical role in the inflammatory processes associated with adverse events such as aseptic loosening of the prosthetic joints and bone degeneration process called osteolysis. Upon interaction with metal wear particles, endothelial cells upregulate pro-inflammatory cytokines and other factors that enhance a localized immune response. However, the role of endothelial cells in the generation of MGCs has not been completely investigated. We developed a three-dimensional peripheral tissue-equivalent model (PTE) consisting of collagen gel, supporting a monolayer of endothelial cells and human peripheral blood mononuclear cells (PBMCs) on top, which mimics peripheral tissue under normal physiological conditions. The cultures were incubated for 14 days with Cobalt chromium alloy (CoCr ASTM F75, 1–5 micron) wear particles. PBMC were allowed to transit the endothelium and harvested cells were analyzed for MGC generation via flow cytometry. An increase in forward scatter (cell size) and in the propidium iodide (PI) uptake (DNA intercalating dye) was used to identify MGCs. Our results show that endothelial cells induce the generation of MGCs to a level 4 fold higher in 3-dimentional PTE system as compared to traditional 2-dimensional culture plates. Further characterization of MGCs showed upregulated expression of tartrate resistant alkaline phosphatase (TRAP) and dendritic cell specific transmembrane protein, (DC-STAMP), which are markers of bone degrading cells called osteoclasts. In sum, we have established a robust and relevant model to examine MGC and osteoclast formation in a tissue like environment using flow cytometry and RT-PCR. With endothelial cells help, we observed a consistent generation of metal wear particle- induced MGCs, which heralds metal on metal hip failures. PMID:25894745

  1. Effects of prosthesis surface roughness on the failure process of cemented hip implants after stem-cement debonding.

    PubMed

    Verdonschot, N; Tanck, E; Huiskes, R

    1998-12-15

    Retrieval studies suggest that the loosening process of the cemented femoral components of total hip arthroplasties is initiated by failure of the bond between the prosthesis and the cement mantle. Finite element (FE) analyses have demonstrated that stem-cement debonding has stress-producing effects in the cement mantle. High interface friction, which corresponds to a degree of surface roughness, reduces these stresses. In experiments, however, debonded rough stems produced more cement damage than polished ones; in the Swedish Hip Register polished stems were clinically superior with respect to stems with a mat surface finish. The purpose of the present study was to investigate this contradiction. For this purpose, global and local FE models with debonded stem-cement interfaces were used to study the effects of prosthesis surface roughness on the cement stresses on a global scale and microscale, respectively. Similar to earlier numerical studies, the global FE model predicted that an increased surface roughness of the stem reduced the stresses in the cement mantle. The local model provided insight in the load-transfer mechanism on a microscale and could explain the experimental and clinical findings. The local cement peak stresses around the asperities of the surface roughness profile increased with increasing surface roughness and decreased again beyond a particular roughness value. Cement abrasion is caused by localized stresses in combination with micromotion. From this study it can be concluded that to minimize cement abrasion, debonded stems should either have a polished microstructure to minimize the local cement stresses or have a profiled macrostructure to minimize micromotions at the stem-cement interface. PMID:9827679

  2. Cementless Hydroxyapatite Coated Hip Prostheses

    PubMed Central

    Herrera, Antonio; Mateo, Jesús; Gil-Albarova, Jorge; Lobo-Escolar, Antonio; Ibarz, Elena; Gabarre, Sergio; Más, Yolanda

    2015-01-01

    More than twenty years ago, hydroxyapatite (HA), calcium phosphate ceramics, was introduced as a coating for cementless hip prostheses. The choice of this ceramic is due to its composition being similar to organic apatite bone crystals. This ceramic is biocompatible, bioactive, and osteoconductive. These qualities facilitate the primary stability and osseointegration of implants. Our surgical experience includes the implantation of more than 4,000 cementless hydroxyapatite coated hip prostheses since 1990. The models implanted are coated with HA in the acetabulum and in the metaphyseal area of the stem. The results corresponding to survival and stability of implants were very satisfactory in the long-term. From our experience, HA-coated hip implants are a reliable alternative which can achieve long term survival, provided that certain requirements are met: good design selection, sound choice of bearing surfaces based on patient life expectancy, meticulous surgical technique, and indications based on adequate bone quality. PMID:25802848

  3. Cementless hydroxyapatite coated hip prostheses.

    PubMed

    Herrera, Antonio; Mateo, Jesús; Gil-Albarova, Jorge; Lobo-Escolar, Antonio; Ibarz, Elena; Gabarre, Sergio; Más, Yolanda; Gracia, Luis

    2015-01-01

    More than twenty years ago, hydroxyapatite (HA), calcium phosphate ceramics, was introduced as a coating for cementless hip prostheses. The choice of this ceramic is due to its composition being similar to organic apatite bone crystals. This ceramic is biocompatible, bioactive, and osteoconductive. These qualities facilitate the primary stability and osseointegration of implants. Our surgical experience includes the implantation of more than 4,000 cementless hydroxyapatite coated hip prostheses since 1990. The models implanted are coated with HA in the acetabulum and in the metaphyseal area of the stem. The results corresponding to survival and stability of implants were very satisfactory in the long-term. From our experience, HA-coated hip implants are a reliable alternative which can achieve long term survival, provided that certain requirements are met: good design selection, sound choice of bearing surfaces based on patient life expectancy, meticulous surgical technique, and indications based on adequate bone quality. PMID:25802848

  4. Hip Replacement

    MedlinePlus

    Hip replacement is surgery for people with severe hip damage. The most common cause of damage is ... therapy, pain medicines, and exercise haven't helped, hip replacement surgery might be an option for you. ...

  5. [Hip arthroscopy].

    PubMed

    Gollwitzer, H; Banke, I J; Schauwecker, J

    2016-02-01

    Hip arthroscopy represents an important component in the treatment of diseases of the hip joint and is nowadays an indispensible tool in modern hip-preserving surgery. This article provides a review of the basic technical principles, typical indications and complications of hip arthroscopy. Furthermore, current developments as well as possibilities and limitations of the arthroscopic technique are reviewed. PMID:26781702

  6. What is the risk of death or severe harm due to bone cement implantation syndrome among patients undergoing hip hemiarthroplasty for fractured neck of femur? A patient safety surveillance study

    PubMed Central

    Rutter, Paul D; Panesar, Sukhmeet S; Darzi, Ara; Donaldson, Liam J

    2014-01-01

    Objective To estimate the risk of death or severe harm due to bone cement implantation syndrome (BCIS) among patients undergoing hip hemiarthroplasty for fractured neck of femur. Setting Hospitals providing secondary and tertiary care throughout the National Health Service (NHS) in England and Wales. Participants Cases reported to the National Reporting and Learning System (NRLS) in which the reporter clearly describes severe acute patient deterioration associated with cement use in hip hemiarthroplasty for fractured neck of femur (assessed independently by two reviewers). Outcome measures Primary—number of reported deaths, cardiac arrests and periarrests per year. Secondary—timing of deterioration and outcome in relation to cement insertion. Results Between 2005 and 2012, the NRLS received 62 reports that clearly describe death or severe harm associated with the use of cement in hip hemiarthroplasty for fractured neck of femur. There was one such incident for every 2900 hemiarthroplasties for fractured neck of femur during the period. Of the 62 reports, 41 patients died, 14 were resuscitated from cardiac arrest and 7 from periarrest. Most reports (55/62, 89%) describe acute deterioration occurring during or within a few minutes of cement insertion. The vast majority of deaths (33/41, 80%) occurred on the operating table. Conclusions These reports provide narrative evidence from England and Wales that cement use in hip hemiarthroplasty for fractured neck of femur is associated with instances of perioperative death or severe harm consistent with BCIS. In 2009, the National Patient Safety Agency publicised this issue and encouraged the use of mitigation measures. Three-quarters of the deaths in this study have occurred since that alert, suggesting incomplete implementation or effectiveness of those mitigation measures. There is a need for stronger evidence that weighs the risks and benefits of cement in hip hemiarthroplasty for fractured neck of femur. PMID:24924418

  7. Hip Replacement

    MedlinePlus

    ... hip joint are removed and replaced with new, artificial parts. These artificial parts are called the prosthesis. The goals of ... less active and put less stress on the artificial hip than do younger people. In more recent ...

  8. Nanoparticles based brachytherapy spacers for delivery of localized combined chemo-radiation therapy

    PubMed Central

    Kumar, Rajiv; Belz, Jodi; Markovic, Stacey; Jadhav, Tej; Fowle, William; Niedre, Mark; Cormack, Robert; Makrigiorgos, Mike G; Sridhar, Srinivas

    2015-01-01

    Purpose In radiation therapy (RT), brachytherapy inert source spacers are commonly used in clinical practice to achieve high spatial accuracy. These implanted devices are critical technical components of precise radiation delivery but provide no direct therapeutic benefits. Materials and Methods Here we have fabricated Implantable Nanoplatforms or Chemo-Radiation Therapy (INCeRT) spacers loaded with silica nanoparticles (SNPs) conjugated containing a drug, to act as a slow release drug depot for simultaneous localized chemo-radiation therapy. The spacers are made of poly(lactic-coglycolic) acid (PLGA) as matrix, were physically identical (size) to the commercially available brachytherapy spacers (5mm×0.8mm). The silica nanoparticles with diameter 250nm conjugated with near infrared fluorophore Cy7.5 as a model drug and the INCeRT spacers were characterized in terms of size, morphology and composition using different instrumentation techniques. The spacers were further doped with anticancer drug, docetaxel. We have evaluated the in vivo stability, biocompatibility and biodegradation of these spacers in live mouse tissues. Results The electron microscopy studies showed that nanoparticles were distributed throughout the spacers. These INCeRT spacers remained stable and can be tracked using optical fluorescence. In vivo optical imaging studies showed a slow diffusion of nanoparticles from the spacer to the adjacent tissue as opposed to the control Cy7.5-PLGA spacer which showed rapid disintegration in a few days with a burst release of Cy7.5. The docetaxel spacers showed suppression of tumor growth as opposed to control mice over 16 days. Conclusions The imaging with the Cy7.5-spacer and therapeutic efficacy with docetaxel-spacers supports the hypothesis that INCeRT spacers can be used for delivering the drugs in slow, sustained manner in conjunction with brachytherapy, as opposed to rapid clearance of the drugs when administered systemically. The results demonstrate that these spacers with tailored release profiles have potential in improving the combined therapeutic efficacy of chemo-radiation therapy (CRT). PMID:25636762

  9. Nanoparticle-Based Brachytherapy Spacers for Delivery of Localized Combined Chemoradiation Therapy

    SciTech Connect

    Kumar, Rajiv; Belz, Jodi; Markovic, Stacey; Jadhav, Tej; Fowle, William; Niedre, Mark; Cormack, Robert; Makrigiorgos, Mike G.; Sridhar, Srinivas

    2015-02-01

    Purpose: In radiation therapy (RT), brachytherapy-inert source spacers are commonly used in clinical practice to achieve high spatial accuracy. These implanted devices are critical technical components of precise radiation delivery but provide no direct therapeutic benefits. Methods and Materials: Here we have fabricated implantable nanoplatforms or chemoradiation therapy (INCeRT) spacers loaded with silica nanoparticles (SNPs) conjugated containing a drug, to act as a slow-release drug depot for simultaneous localized chemoradiation therapy. The spacers are made of poly(lactic-co-glycolic) acid (PLGA) as matrix and are physically identical in size to the commercially available brachytherapy spacers (5 mm × 0.8 mm). The silica nanoparticles, 250 nm in diameter, were conjugated with near infrared fluorophore Cy7.5 as a model drug, and the INCeRT spacers were characterized in terms of size, morphology, and composition using different instrumentation techniques. The spacers were further doped with an anticancer drug, docetaxel. We evaluated the in vivo stability, biocompatibility, and biodegradation of these spacers in live mouse tissues. Results: The electron microscopy studies showed that nanoparticles were distributed throughout the spacers. These INCeRT spacers remained stable and can be tracked by the use of optical fluorescence. In vivo optical imaging studies showed a slow diffusion of nanoparticles from the spacer to the adjacent tissue in contrast to the control Cy7.5-PLGA spacer, which showed rapid disintegration in a few days with a burst release of Cy7.5. The docetaxel spacers showed suppression of tumor growth in contrast to control mice over 16 days. Conclusions: The imaging with the Cy7.5 spacer and therapeutic efficacy with docetaxel spacers supports the hypothesis that INCeRT spacers can be used for delivering the drugs in a slow, sustained manner in conjunction with brachytherapy, in contrast to the rapid clearance of the drugs when administered systemically. The results demonstrate that these spacers with tailored release profiles have potential in improving the combined therapeutic efficacy of chemoradiation therapy.

  10. The use of spacers (static and mobile) in infection knee arthroplasty.

    PubMed

    Mazzucchelli, Luca; Rosso, Federica; Marmotti, Antongiulio; Bonasia, Davide Edoardo; Bruzzone, Matteo; Rossi, Roberto

    2015-12-01

    Revision total knee arthroplasty (TKA) is the treatment of choice in patients with periprosthetic joint infection. It may be performed in either a single stage or two stages. In the latter option, between stages, an antibiotic-loaded spacer may be used to maintain a certain amount of joint stability and mobility after the infected implant is removed, adding an intra-articular concentration of antibiotics. There are two types of antibiotic-loaded cement spacers: static and dynamic. Static spacers basically create a temporary arthrodesis with antibiotic-loaded cement and usually are handmade within the surgical field. Dynamic spacers can be created intraoperatively by using different tools or may be prepackaged by the manufacturer; they allow range of motion between stages. In this article, the authors review the indications, surgical techniques, and results for static and dynamic spacers in two-stage revision TKA. PMID:26395472

  11. The Management of the Symptomatic Patient With a Metal-on-Metal Hip Prosthesis.

    PubMed

    Harrington, Kate; Phelan, Emma; Torreggiani, William C; Doody, Orla

    2016-02-01

    Metal-on-metal (MoM) hip implants have gained popularity due to their greater stability and reduction in implant failure compare to metal-on-polyethylene prostheses. However, as well as carrying general risks of hip implantation, risks specifically associated with MoM implants have been well documented in recent years. Conditions such as pseudotumours or aseptic lymphocyte-dominated vasculitis-associated lesions are specific to MoM hip implants. In this review we discuss the typical patient presentation, the investigations that should be performed, the typical findings on various imaging modalities, and the treatment options of symptomatic patients with MoM hip arthroplasties. PMID:26800622

  12. Toxicology of wear particles of cobalt-chromium alloy metal-on-metal hip implants Part II: Importance of physicochemical properties and dose in animal and in vitro studies as a basis for risk assessment.

    PubMed

    Madl, Amy K; Kovochich, Michael; Liong, Monty; Finley, Brent L; Paustenbach, Dennis J; Oberdrster, Gnter

    2015-07-01

    The objective of the Part II analysis was to evaluate animal and in vitro toxicology studies of CoCr particles with respect to their physicochemistry and dose relevance to metal-on-metal (MoM) implant patients as derived from Part I. In the various toxicology studies, physicochemical characteristics were infrequently considered and administered doses were orders of magnitude higher than what occurs in patients. Co was consistently shown to rapidly release from CoCr particles for distribution and elimination from the body. CoCr micron sized particles appear more biopersistent in vivo resulting in inflammatory responses that are not seen with similar mass concentrations of nanoparticles. We conclude, that in an attempt to obtain data for a complete risk assessment, future studies need to focus on physicochemical characteristics of nano and micron sized particles and on doses and dose metrics relevant to those generated in patients or in properly conducted hip simulator studies. PMID:25735266

  13. Relative importance of gait vs. joint positioning on hip contact forces after total hip replacement.

    PubMed

    Foucher, Kharma C; Hurwitz, Debra E; Wimmer, Markus A

    2009-12-01

    Implant loosening is a common indication for total hip replacement (THR) revision. High contact forces and implant twisting moments are thought to be associated with implant loosening. Relationships between joint positioning and hip forces, or outcomes, have been investigated through in vivo and in vitro modalities. Relationships between hip forces and gait are less understood, despite repeated findings that gait following a THR does not fully return to normal. We tested the hypothesis that gait parameters would be better predictors of implant force (peak contact forces and peak twisting moment during walking) than joint positioning parameters. Subjects underwent gait analysis, hip force modeling, and measurement of clinical radiographs 1 year after successful THR surgery. Gait parameters were consistently more influential in determining hip forces. Alone, gait explained as much as 67% of the variation in force, compared to a maximum of 33% by joint geometry. Combinations of gait and joint positioning parameters together explained up to 86% of the variation in hip force parameters. Results suggest that gait may provide a valuable postoperatively modifiable target to improve hip loads and potentially reduce the risk for implant loosening. PMID:19514072

  14. Review on squeaking hips

    PubMed Central

    Levy, Yadin David; Munir, Selin; Donohoo, Shane; Walter, William Lindsay

    2015-01-01

    Squeaking is a well-recognized complication for hard-on-hard bearings. The nature of squeaking is not yet completely understood however it is considered a multifactorial phenomenon. Patient, implant, and surgical factors play a role in squeaking. It is believed that mechanisms damaging the fluid film lubrication in which these bearings function optimally have a critical role. Such mechanisms include edge loading, stripe wear, impingement, third body particles and ceramic fracture. The resonance of metallic parts can produce noise in the human audible range hence the implant metallurgic composition and design may play a role. Implant positioning can facilitate impingement and edge loading enhancing the occurrence of squeaking. The recent introduction of large heads (> 36 mm) 4th generation ceramic-on-ceramic bearing may accentuate the conditions facilitating noise formation; however the current literature is insufficient. Clinically, squeaking may manifest in extreme hip positions or during normal gait cycle however it is rarely associated with pain. Evaluations of patients with squeaking include clinical and radiographic assessments. Computer tomography is recommended as it can better reveal ceramic breakage and implant malposition. The treatments for most squeaking patients include reassurance and activity modification. However for some, noise can be a problem, requiring further surgical intervention. In the occurrence of ceramic fracture, implant failure, extreme components malposition, instability and impingement, surgery should be advised. This review will aim to discuss the current literature regarding squeaking. PMID:26601063

  15. Review on squeaking hips.

    PubMed

    Levy, Yadin David; Munir, Selin; Donohoo, Shane; Walter, William Lindsay

    2015-11-18

    Squeaking is a well-recognized complication for hard-on-hard bearings. The nature of squeaking is not yet completely understood however it is considered a multifactorial phenomenon. Patient, implant, and surgical factors play a role in squeaking. It is believed that mechanisms damaging the fluid film lubrication in which these bearings function optimally have a critical role. Such mechanisms include edge loading, stripe wear, impingement, third body particles and ceramic fracture. The resonance of metallic parts can produce noise in the human audible range hence the implant metallurgic composition and design may play a role. Implant positioning can facilitate impingement and edge loading enhancing the occurrence of squeaking. The recent introduction of large heads (> 36 mm) 4(th) generation ceramic-on-ceramic bearing may accentuate the conditions facilitating noise formation; however the current literature is insufficient. Clinically, squeaking may manifest in extreme hip positions or during normal gait cycle however it is rarely associated with pain. Evaluations of patients with squeaking include clinical and radiographic assessments. Computer tomography is recommended as it can better reveal ceramic breakage and implant malposition. The treatments for most squeaking patients include reassurance and activity modification. However for some, noise can be a problem, requiring further surgical intervention. In the occurrence of ceramic fracture, implant failure, extreme components malposition, instability and impingement, surgery should be advised. This review will aim to discuss the current literature regarding squeaking. PMID:26601063

  16. Total hip arthroplasty for surgical management of advanced tuberculous hip arthritis: Case report

    PubMed Central

    Tan, Shi Ming; Chin, Pak Lin

    2015-01-01

    Tuberculosis (TB) arthritis of the hip is a debilitating disease that often results in severe cartilage destruction and degeneration of the hip. In advanced cases, arthrodesis of the hip confers benefits to the young, high-demand and active patient. However, many of these patients go on to develop degenerative arthritis of the spine, ipsilateral knee and contralateral hip, necessitating the need for a conversion to total hip arthroplasty. Conversion of a previously fused hip to a total hip arthroplasty presents as a surgical challenge due to altered anatomy, muscle atrophy, previous surgery and implants, neighbouring joint arthritis and limb length discrepancy. We report a case of advanced TB arthritis of the hip joint in a middle-aged Singaporean Chinese gentleman with a significant past medical history of miliary tuberculosis and previous hip arthrodesis. Considerations in pre-operative planning, surgical approaches and potential pitfalls are discussed and the operative technique utilized and post-operative rehabilitative regime of this patient is described. This case highlights the necessity of pre-operative planning and the operative technique used in the conversion of a previous hip arthrodesis to a total hip arthroplasty in a case of TB hip arthritis. PMID:25793173

  17. Unilateral total hip replacement patients with symptomatic leg length inequality have abnormal hip biomechanics during walking

    PubMed Central

    Li, Junyan; McWilliams, Anthony B.; Jin, Zhongmin; Fisher, John; Stone, Martin H.; Redmond, Anthony C.; Stewart, Todd D.

    2015-01-01

    Background Symptomatic leg length inequality accounts for 8.7% of total hip replacement related claims made against the UK National Health Service Litigation authority. It has not been established whether symptomatic leg length inequality patients following total hip replacement have abnormal hip kinetics during gait. Methods Hip kinetics in 15 unilateral total hip replacement patients with symptomatic leg length inequality during gait was determined through multibody dynamics and compared to 15 native hip healthy controls and 15 ‘successful’ asymptomatic unilateral total hip replacement patients. Finding More significant differences from normal were found in symptomatic leg length inequality patients than in asymptomatic total hip replacement patients. The leg length inequality patients had altered functions defined by lower gait velocity, reduced stride length, reduced ground reaction force, decreased hip range of motion, reduced hip moment and less dynamic hip force with a 24% lower heel-strike peak, 66% higher mid-stance trough and 37% lower toe-off peak. Greater asymmetry in hip contact force was also observed in leg length inequality patients. Interpretation These gait adaptions may affect the function of the implant and other healthy joints in symptomatic leg length inequality patients. This study provides important information for the musculoskeletal function and rehabilitation of symptomatic leg length inequality patients. PMID:25900447

  18. Recent Patents and Designs on Hip Replacement Prostheses

    PubMed Central

    Derar, H; Shahinpoor, M

    2015-01-01

    Hip replacement surgery has gone through tremendous evolution since the first procedure in 1840. In the past five decades the advances that have been made in technology, advanced and smart materials innovations, surgical techniques, robotic surgery and methods of fixations and sterilization, facilitated hip implants that undergo multiple design revolutions seeking the least problematic implants and a longer survivorship. Hip surgery has become a solution for many in need of hip joint remedy and replacement across the globe. Nevertheless, there are still long-term problems that are essential to search and resolve to find the optimum implant. This paper reviews several recent patents on hip replacement surgery. The patents present various designs of prostheses, different materials as well as methods of fixation. Each of the patents presents a new design as a solution to different issues ranging from the longevity of the hip prostheses to discomfort and inconvenience experienced by patients in the long-term. PMID:25893020

  19. Hip arthroscopy☆

    PubMed Central

    de Amorim Cabrita, Henrique Antônio Berwanger; de Castro Trindade, Christiano Augusto; de Campos Gurgel, Henrique Melo; Leal, Rafael Demura; de Souza Marques, Ricardo da Fonseca

    2014-01-01

    Hip arthroscopy is a safe method for treating a variety of pathological conditions that were unknown until a decade ago. Femoroacetabular impingement is the commonest of these pathological conditions and the one with the best results when treated early on. The instruments and surgical technique for hip arthroscopy continue to evolve. New indications for hip arthroscopy has been studied as the ligamentum teres injuries, capsular repair in instabilities, dissection of the sciatic nerve and repair of gluteal muscles tears (injuries to the hip rotator cuff), although still with debatable reproducibility. The complication rate is low, and ever-better results with fewer complications should be expected with the progression of the learning curve. PMID:26229924

  20. Rose Hip

    MedlinePlus

    ... rose hip might increase the risk of complications. Kidney stones: Large amounts of the vitamin C in rose hop might increase the risk for kidney stones. Iron-related disorders such as hemochromatosis, thalassemia, or ...

  1. Implant wear mechanisms--basic approach.

    PubMed

    Bhatt, Himanshu; Goswami, Tarun

    2008-12-01

    Numerous parameters control the long-term performance of a total hip joint arthroplasty. The articulating motions between the femoral and the acetabular components produce wear debris in a hip implant. Surface roughness, clearance, coefficient of friction and sliding distance are found to be contributing parameters that affect wear rates. Wear produced in a hip implant leads to the loosening of a hip prosthesis and thus failure of the hip implant. Ultra-high-molecular-weight polyethylene (UHMWPE) has been successfully used as an acetabular weight bearing component in the THR applications. Cross-linked UHMWPE was found to improve the lifespan of an artificial hip. A gradient cross-linking of UHMWPE has been observed to be a recent development in implant bearing materials. During in vitro studies, gradient cross-linked UHMWPE showed nearly undetectable wear rates. PMID:18824778

  2. [Use of gold implants as a treatment of pain related to canine hip dysplasia--a review. Part 1: Background and current state of research regarding the effects of implanting gold in tissue].

    PubMed

    Deisenroth, A; Nolte, I; Wefstaedt, P

    2013-01-01

    Gold-bead implantation as a method of pain treatment in dogs suffering from osteoarthritic disease is receiving increasing attention in veterinary medicine. For the present article, publications from veterinary books and journals were collected and evaluated, together with related articles in human medicine. After providing an overview of the historical use of gold and gold compounds, the technique of implanting this noble metal is introduced. The reasons for establishing the terms gold acupuncture and gold (bead) implantation are described, considering the question whether and what kind of methodological differences exist behind these terms. Next, previous publications concerning the effects of gold implantation in tissue are summarised. In 2002 it was proven that gold ions are released from the surface of gold implants by a process termed dissolucytosis. Subsequent publications further investigated details about the interaction between gold ions and tissue as well as the distribution pattern of bio-released ions. Gold compounds were previously used for chrysotherapy in human medicine until medication with fewer side effects became established. The anti-inflammatory and immuno-modulatory properties of gold compounds were used to treat rheumatoid arthritis. Current research aims to ascertain whether the anti-inflammatory and immuno-modulating effects of gold compounds are imitated by gold ions released from gold implants at a local level. In conclusion, the present review summarises important findings about the effects of gold implanted in tissue. However, further research is necessary to estimate the limitations and benefits of this auromedication. PMID:23608966

  3. Biotribology of artificial hip joints

    PubMed Central

    Di Puccio, Francesca; Mattei, Lorenza

    2015-01-01

    Hip arthroplasty can be considered one of the major successes of orthopedic surgery, with more than 350000 replacements performed every year in the United States with a constantly increasing rate. The main limitations to the lifespan of these devices are due to tribological aspects, in particular the wear of mating surfaces, which implies a loss of matter and modification of surface geometry. However, wear is a complex phenomenon, also involving lubrication and friction. The present paper deals with the tribological performance of hip implants and is organized in to three main sections. Firstly, the basic elements of tribology are presented, from contact mechanics of ball-in-socket joints to ultra high molecular weight polyethylene wear laws. Some fundamental equations are also reported, with the aim of providing the reader with some simple tools for tribological investigations. In the second section, the focus moves to artificial hip joints, defining materials and geometrical properties and discussing their friction, lubrication and wear characteristics. In particular, the features of different couplings, from metal-on-plastic to metal-on-metal and ceramic-on-ceramic, are discussed as well as the role of the head radius and clearance. How friction, lubrication and wear are interconnected and most of all how they are specific for each loading and kinematic condition is highlighted. Thus, the significant differences in patients and their lifestyles account for the high dispersion of clinical data. Furthermore, such consideration has raised a new discussion on the most suitable in vitro tests for hip implants as simplified gait cycles can be too far from effective implant working conditions. In the third section, the trends of hip implants in the years from 2003 to 2012 provided by the National Joint Registry of England, Wales and Northern Ireland are summarized and commented on in a discussion. PMID:25621213

  4. Cement augmentation of the acetabulum for revision total hip arthroplasty for infection.

    PubMed

    Rogers, Benedict A; Kuchinad, R; Garbedian, S; Backstein, D; Gross, A E; Safir, O A

    2015-02-01

    Antibiotic-loaded cement spacers in first-stage revision hip arthroplasty for infection are associated with a high dislocation and fracture rate. This technical note describes a novel surgical technique, utilizing screws and cement, improving acetabular coverage and reducing the risk of mechanical failure. Fifteen infected hip prostheses underwent removal, cement acetabular augmentation and insertion of a femoral cement spacer. Eleven hips had successful infection eradication and subsequently underwent a second stage revision procedure a mean duration of 15 weeks (9-48) after the first stage. No dislocations or fractures of the cement spacers were observed. This technique affords the potential to reduce the duration of time cement spacers remaining in situ, provides enhanced mechanical stability and improved antibiotic elution through cement-on-cement articulation. PMID:25532622

  5. Total hip replacement for high dislocated hips without femoral shortening osteotomy.

    PubMed

    Zhao, X; Zhu, Z-A; Xie, Y-Z; Yu, B; Yu, D-G

    2011-09-01

    When performing total hip replacement (THR) in high dislocated hips, the presence of soft-tissue contractures means that most surgeons prefer to use a femoral shortening osteotomy in order to avoid the risk of neurovascular damage. However, this technique will sacrifice femoral length and reduce the extent of any leg-length equalisation. We report our experience of 74 THRs performed between 2000 and 2008 in 65 patients with a high dislocated hip without a femoral shortening osteotomy. The mean age of the patients was 55 years (46 to 72) and the mean follow-up was 42 months (12 to 78). All implants were cementless except for one resurfacing hip implant. We attempted to place the acetabular component in the anatomical position in each hip. The mean Harris hip score improved from 53 points (34 to 74) pre-operatively to 86 points (78 to 95) at final follow-up. The mean radiologically determined leg lengthening was 42 mm (30 to 66), and the mean leg-length discrepancy decreased from 36 mm (5 to 56) pre-operatively to 8.5 mm (0 to 18) postoperatively. Although there were four (5%) post-operative femoral nerve palsies, three had fully resolved by six months after the operation. No loosening of the implant was observed, and no dislocations or infections were encountered. Total hip replacement without a femoral shortening osteotomy proved to be a safe and effective surgical treatment for high dislocated hips. PMID:21911529

  6. Photoelastic and thermoelastic measurement of stress on the proximal femur before and after implantation of a hip prosthesis with retention of the femoral neck.

    PubMed

    Refior, Jans Jürgen; Schidlo, Christoph; Plitz, Wolfgang; Heining, Sandro

    2002-05-01

    This study demonstrated the improved medial support and the transfer of load onto the retained neck of the femur using seven fresh frozen femurs. Results confirm the reliability of the thermoelastic stress analysis method, which is comparable to the photoelastic surface coating method, but with greater sensitivity. The loading pattern after stem implantation shows a homogeneous transfer of force onto the preserved femoral neck. After femoral neck removal, an inhomogeneous increase of the intertrochanteric compression loading was observed. Therefore, improved biomechanical conditions are created for a permanently stable implantation of stem prostheses with retention of the femoral neck. PMID:12046909

  7. Generator stator core vent duct spacer posts

    DOEpatents

    Griffith, John Wesley; Tong, Wei

    2003-06-24

    Generator stator cores are constructed by stacking many layers of magnetic laminations. Ventilation ducts may be inserted between these layers by inserting spacers into the core stack. The ventilation ducts allow for the passage of cooling gas through the core during operation. The spacers or spacer posts are positioned between groups of the magnetic laminations to define the ventilation ducts. The spacer posts are secured with longitudinal axes thereof substantially parallel to the core axis. With this structure, core tightness can be assured while maximizing ventilation duct cross section for gas flow and minimizing magnetic loss in the spacers.

  8. Spacer grid assembly and locking mechanism

    DOEpatents

    Snyder, Jr., Harold J.; Veca, Anthony R.; Donck, Harry A.

    1982-01-01

    A spacer grid assembly is disclosed for retaining a plurality of fuel rods in substantially parallel spaced relation, the spacer grids being formed with rhombic openings defining contact means for engaging from one to four fuel rods arranged in each opening, the spacer grids being of symmetric configuration with their rhombic openings being asymmetrically offset to permit inversion and relative rotation of the similar spacer grids for improved support of the fuel rods. An improved locking mechanism includes tie bars having chordal surfaces to facilitate their installation in slotted circular openings of the spacer grids, the tie rods being rotatable into locking engagement with the slotted openings.

  9. Indications and results of hip resurfacing

    PubMed Central

    McMinn, D. J. W.; Ziaee, H.; Pradhan, C.

    2010-01-01

    The best indication for hip resurfacing is a young active patient with severe hip arthritis, good hip morphology and reasonable bone quality. With revision of either component for any reason as the endpoint, there were 68 revisions in our series of 3,095 consecutive Birmingham Hip Resurfacings (BHR) (19972009), including all diagnoses in all ages. This equates to a revision rate of 2.2% and survivorships of 99, 97 and 96% at five, ten and 13years, respectively. In patients under 55years with osteoarthritis, the survivorship is 99 and 98% at ten and 13years. These results provide medium-term evidence that BHR when performed well in properly selected patients offers excellent outcomes and implant survivorship. Small changes to implant materials and design can affect joint function and survivorship significantly as seen from the withdrawal of certain resurfacing devices recently from clinical use. The clinical history of one device cannot be extrapolated to other devices. PMID:21079954

  10. [An assistant artificial hip joint].

    PubMed

    Shi, Zhen-man; Chen, Jian-chang; Shi, Jiang; Chen, Wenhong; Zhang, Chunhao

    2002-01-01

    The assistant artificial hip joint (AAHJ) is a new impermanent hip support implanted in the body. It is used for treatment of ischemic necrosis of the femoral head at the early stage. It reserves the natural femoral head, increases its containment and decreases its load, thus makes the recovery of the necrosed femoral head. The AAHJ's moving axis center is the same as that of the femoral head. Therefore, the moving range of the hip joint is very close to the normal postoperatively. The patient can walk with loading in 3 weeks after the surgical operation, and can regain his (or her) daily work and life in 2 to 3 months of the operation. The AAHJ's structure is simple and the price is cheap. PMID:16104164

  11. NEW BEARING SURFACES IN TOTAL HIP REPLACEMENT

    PubMed Central

    Schwartsmann, Carlos Roberto; Boschin, Leonardo Carbonera; Gonçalves, Ramiro Zilles; Yépez, Anthony Kerbes; de Freitas Spinelli, Leandro

    2015-01-01

    Total hip arthroplasty is being increasingly indicated for younger and more active patients, in addition to a naturally growing demand for the procedure because of increasing life expectancy among patients. The high costs of this surgery and the controversies regarding implant performance have made this topic the subject of constant research, seeking new materials with better resistance to wear and better biocompatibility. The present article provides a review of new surfaces in total hip arthroplasty. PMID:27042614

  12. Evaluation of the hip center in total hip arthroplasty for old developmental dysplasia.

    PubMed

    Flecher, Xavier; Parratte, Sebastien; Brassart, Nicolas; Aubaniac, Jean-Manuel; Argenson, Jean-Noël

    2008-12-01

    We describe the problems with positioning the hip center according to the severity of dislocation in 97 cementless total hip arthroplasty for developmental dysplasia of the hip. The mean location of the hip center from the interteardrop was 30.4 +/- 8.7 mm horizontally and 23.4 +/- 5.4 mm vertically. The presence of a limp correlated with a superior placement of the cup. Four cups were revised, 2 of which with a significant high hip center. The survival rate of the acetabular component was 95% at 12 years. Craniopodal repositioning was easy in class 1. In class 2, the cup was the largest. In class 3, the greatest variations of the hip center were found. In class 4, the smallest implants were necessary for positioning in the true acetabulum. PMID:18534475

  13. Three-dimensional computerized selection of hip prostheses in patients with congenital dislocated hips.

    PubMed

    Gelalis, L D; Xenakis, T A; Hantes, M; Vartziotis, K; Soucacos, P N

    2001-11-01

    This study assessed the effectiveness of the combined use of computed tomography (CT) and computer-aided design (CAD) in the preoperative evaluation and implant selection in 20 patients (20 hips) with congenital dislocation of the hip who were scheduled to undergo total hip arthroplasty. Computerized selection of the femoral implant with optimum fit and fill was made after a three-dimensional reconstruction of the femoral canal using CT data and CAD. Implantation of all sizes of 5 noncemented and 2 cemented femoral implants was simulated using CATIA software (IBM, Kingstone, NY). When patients underwent surgery, 18 of 20 preselected prostheses agreed by type and size with the prostheses implanted. The remaining 2 preselected implants agreed by type only. In patients with dislocated and dysplastic hips, combined use of CT and CAD allows effective preoperative planning by providing the surgeon with vital information about the proximal femoral canal geometry and the possible femoral implant with optimum fit and fill to be used. PMID:11727804

  14. Fungal Periprosthetic Joint Infection of the Hip: A Systematic Review

    PubMed Central

    Schoof, Benjamin; Jakobs, Oliver; Schmidl, Stefan; Klatte, Till Orla; Frommelt, Lars; Gehrke, Thorsten; Gebauer, Matthias

    2015-01-01

    Periprosthetic joint infection (PJI) is a severe complication of total joint arthroplasty with an incidence of approximately 1%. Due to the high risk of persisting infection, successful treatment of fungal PJI is challenging. The purpose of this study was to gain insight into the current management of fungal PJI of the hip and, by systematically reviewing the cases published so far, to further improve the medical treatment of this serious complication of total hip arthroplasty. Thus, we conducted a systematic review of the available literature concerning fungal PJI in total hip arthroplasty, including 45 cases of fungal PJI. At the moment a two-stage revision procedure is favorable and there is an ongoing discussion on the therapeutic effect of antifungal drug loaded cement spacers on fungal periprosthetic infections of the hip. Due to the fact that there is rare experience with it, there is urgent need to establish guidelines for the treatment of fungal infections of total hip arthroplasty. PMID:25874063

  15. Diamond coated total hip replacements.

    PubMed

    Lappalainen, R; Anttila, A; Heinonen, H

    1998-07-01

    Diamond has many superior, desired characteristics of implant materials such as low friction, high wear and corrosion resistance, and well bonding surface to bone. The potential of diamond for total hip replacement implants was studied in the form of amorphous diamond coatings on conventional metal implant materials. Amorphous diamond coatings (sp3 bonding fraction 80%, thickness 0.2 to 10 microns) were deposited on stainless steel AISI316L, Ti6A14V, and CoCrMo alloys using filtered pulsed plasma are discharge method. Superior attachment of coatings to the implant materials was achieved by using high energy plasma beams to deposit amorphous diamond and proper intermediate layers. Previously it was shown that these coatings are biocompatible causing no local tissue reactions. Tribologic studies using a pin on disk apparatus with coated or uncoated implant materials in 1 wt.% NaCl distilled water were performed. A simplified hip joint simulator was used for preliminary testing of metal on polyethylene and metal on metal artificial hip joints modified with amorphous diamond coating. The average coefficients of friction were typically in the range of 0.03 to 0.11 for amorphous diamond coated materials. In the case of metal on metal hip implants, the average friction during initial running in period was improved (coefficient of friction = 0.07) compared with the same metal on metal pair (coefficient of friction = 0.22) and sliding was significantly smoother. In pin on disk wear tests, the average wear factors obtained were 140.10(-6), 5.0.10(-6), and < 0.1.10(-6) mm3/Nm for the pairs of AISI316L, CoCrMo, and the same materials with amorphous diamond coating. The corrosion rates of these implant materials in 10 wt.% HCl solution were decreased by a factor of 10,000 to 15,000 and any damage of the coatings was not observed in 6 months. The results of the tests show that in all the combinations studied, amorphous diamond coating improved definitely the wear and corrosion resistance compared with the uncoated materials. PMID:9678039

  16. Results of hip resurfacing

    PubMed Central

    Favetti, Fabio; Casella, Filippo; Papalia, Matteo; Panegrossi, Gabriele

    2011-01-01

    Background The renewed popularity of resurfacing hip arthroplasty in the last 10 years has generated a remarkable quantity of scientific contributions based on mid- and short-term follow-up. More than one paper has reported a consistent early revision rate as a consequence of biological or biomechanical failure. Two major complications are commonly described with resurfacing implants: avascular necrosis and femoral-neck fracture. A close relationship between these two events has been suggested, but not firmly demonstrated, whereas cementing technique seems to be better understood as potential cause of failure. Methods We performed an in vitro study in which four different resurfacing implants were evaluated with a simulated femoral head, two types of cement, (low and high viscosity) and two cementing techniques: direct (cement apposition directly on the femoral head) and indirect (cement poured into the femoral component). Results High-viscosity cement showed homogeneous distribution over the entire femoral head. Low-viscosity cement showed a massive polar concentration with insufficient, if not absent, distribution in the equatorial zone. Conclusion Polar cement concentration could be a risk factor for early implant failure due to two effects on the femoral head: biological (excessive local exothermic reaction could cause osteocyte necrosis) and biomechanical (which could lead to uneven load distribution on the femoral head). PMID:21234563

  17. 21 CFR 888.3310 - Hip joint metal/polymer constrained cemented or uncemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Hip joint metal/polymer constrained cemented or... Hip joint metal/polymer constrained cemented or uncemented prosthesis. (a) Identification. A hip joint metal/polymer constrained cemented or uncemented prosthesis is a device intended to be implanted...

  18. 21 CFR 888.3310 - Hip joint metal/polymer constrained cemented or uncemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint metal/polymer constrained cemented or... Hip joint metal/polymer constrained cemented or uncemented prosthesis. (a) Identification. A hip joint metal/polymer constrained cemented or uncemented prosthesis is a device intended to be implanted...

  19. 21 CFR 888.3310 - Hip joint metal/polymer constrained cemented or uncemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Hip joint metal/polymer constrained cemented or... Hip joint metal/polymer constrained cemented or uncemented prosthesis. (a) Identification. A hip joint metal/polymer constrained cemented or uncemented prosthesis is a device intended to be implanted...

  20. 21 CFR 888.3310 - Hip joint metal/polymer constrained cemented or uncemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Hip joint metal/polymer constrained cemented or... Hip joint metal/polymer constrained cemented or uncemented prosthesis. (a) Identification. A hip joint metal/polymer constrained cemented or uncemented prosthesis is a device intended to be implanted...

  1. 21 CFR 888.3310 - Hip joint metal/polymer constrained cemented or uncemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Hip joint metal/polymer constrained cemented or... Hip joint metal/polymer constrained cemented or uncemented prosthesis. (a) Identification. A hip joint metal/polymer constrained cemented or uncemented prosthesis is a device intended to be implanted...

  2. 21 CFR 888.3340 - Hip joint metal/composite semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint metal/composite semi-constrained... Hip joint metal/composite semi-constrained cemented prosthesis. (a) Identification. A hip joint metal/composite semi-constrained cemented prosthesis is a two-part device intended to be implanted to replace...

  3. 21 CFR 888.3340 - Hip joint metal/composite semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Hip joint metal/composite semi-constrained... Hip joint metal/composite semi-constrained cemented prosthesis. (a) Identification. A hip joint metal/composite semi-constrained cemented prosthesis is a two-part device intended to be implanted to replace...

  4. [Total hip arthroplasty in the treatment of arthrosis with coexistent high developmental hip dislocation].

    PubMed

    Matewski, Dariusz; Szymkowiak, Edward; Gumański, Ryszard

    2008-01-01

    The question if total hip arthroplasty ought to be advised for patients with high developmental hip dislocation is still actual. The subject of hip arthroplasty, as a method of surgical treatment of high developmental hip dislocation, was analyzed on the base of follow up of seven patients, who underwent this procedure. The mean age of patients was 44.5 (+/- 12.6) years. The mean time of follow up was 64.4 (21.6) months. Initial three patients were treated in two stage regime. In first stage, a surgical hip liberalization and skeletal traction through 3 weeks was performed. In 2nd stage we did total hip replacement with simultaneous shortening of the femoral shaft just below the lesser trochanter. In next four patients we performed total hip arthroplasty with simultaneous shortening of the femoral shaft in one stage. Protection of undesirable rotational instability after osteotomy was done by means of different ways of osteotomy fixation describe in paper. Applied surgical treatment allowed for implanting a cup of prosthesis in original place of acetabulum and reduction of the big anteversion of the femoral neck. The hip congruency was improved in all patients. Score in functional Harris hip scale increased from mean value of 50 points before hip arthroplasty to mean value of 85 points after surgery. The symptoms of late consolidation of osteotomy were observed in one patient with transverse osteotomy without anty-rotational fixation. Total hip replacement with simultaneous "Z" shortening osteotomy of the femoral shaft give good such clinical as radiological results in the treatment of hip osteoarthritis in accordance to high developmental hip dislocation. PMID:18847022

  5. Bursitis of the Hip

    MedlinePlus

    MENU Return to Web version Bursitis of the Hip Overview What is bursitis? Bursitis (say: “burse-eye- ... bursitis is swelling affecting the bursae of the hip. Bursitis does not only happen in the hip. ...

  6. Alternative bearings in total hip arthroplasty in the young patient.

    PubMed

    Kamath, Atul F; Prieto, Hernan; Lewallen, David G

    2013-10-01

    Total hip arthroplasty is an effective treatment option for advanced hip arthritis in elderly patients. Studies in young patients have traditionally shown less durable results. With current implants, surgical technique, and cementless fixation methods, the durability of total hip arthroplasty may now be related to the wear performance of the bearing surfaces. To improve implant longevity, there are several bearing surface choices currently available for this demanding group of patients. Alternatives must be evaluated in terms of the risks and benefits associated with each articulation, and all new technologies must be carefully monitored over the long term. PMID:24095062

  7. [Technology of cementless hip endoprosthetics].

    PubMed

    Ungethüm, M; Blömer, W

    1987-06-01

    The success achieved with non-cemented hip arthroplasty depends mainly on the stability of the fixation, the quality of the stabilizing bone being just as important as favourable biomechanical conditions. The results of the intensive research and development with respect to the particular features of a non-cemented hip endoprosthesis can be divided into the following basic categories: Biomechanical aspects with special reference to bone related to the design of the prosthesis; material characteristics, such as fatigue strength, tribology, corrosion resistance, and biocompatibility; and development of new materials and coatings to permit direct bonding of implant and bone. With regard to the stem of hip prostheses, the different design parameters of various types are examined to determine their typical design characteristics, such as bearing surface of the collar, geometry of cross section, anatomically adapted shaping, and surface of the implant forming the contact with the bone. The latter can be divided into macroprofiles and macro- and micro-porous coated surfaces. On the other hand, the methods of cementless fixation of acetabular cups can be primarily divided into conical and spherical screw fixation and pegged fixation with additional macroprofiles of porous surfaces. In a separate study of the biomechanical aspects of screwed sockets, the special importance of socket shape and thread geometry are presented with reference to primary stability and long-term fixation of prostheses. PMID:3627790

  8. LISA telescope spacer design investigations

    NASA Astrophysics Data System (ADS)

    Sanjuan, Josep; Mueller, Guido; Livas, Jeffrey; Preston, Alix; Arsenovic, Petar; Castellucci, Kevin; Generie, Joseph; Howard, Joseph; Stebbins, Robin

    The Laser Interferometer Space Antenna (LISA) is a space-based gravitational wave observa-tory with the goal of observing Gravitational Waves (GWs) from astronomical sources in a frequency range from 30 µHz to 0.1 Hz. The detection of GWs at such low frequency requires measurements of distances at the pico-meter level between bodies separated by 5 million kilo-meters. The LISA mission consists of three identical spacecraft (SC) separated by 5 × 106 km forming an equilateral triangle. Each SC contains two optical assemblies and two vacuum en-closures housing one proof mass (PM) in geodesic (free fall) motion each. The two assemblies on one SC are each pointing towards an identical assembly on each of the other two SC to form a non-equal arm interferometer. The measurement of the GW strain is done by measuring the change in the length of the optical path between the PMs of one arm relative to the other arms caused by the pass of a GW. An important element of the Interferometric Measurement System (IMS) is the telescope which, on one hand, gathers the light coming from the far SC (˜100 pW) and, on the other hand, expands and collimates the small outgoing beam ( 1 W) and sends it to the far SC. Due to the very demanding sensitivity requirements care must be taken in the design and validation of the telescope not to degrade the IMS performance. For instance, the diameter of the telescope sets the the shot noise of the IMS and depends critically on the diameter of the primary and the divergence angle of the outgoing beam. As the telescope is rather fast telescope, the divergence angle is a critical function of the overall separation between the primary and secondary. Any long term changes of the distance of more than a a few micro-meter would be detrimental to the LISA mission. Similarly challenging are the requirements on the in-band path-length noise for the telescope which has to be kept below 1 pm Hz-1/2 in the LISA band. Different configurations (on-axis/off axis) and materials such as Silicon Carbide (SiC) and Carbon Fiber Reinforced Plastic (CFRP) are considered to be used in the telescope spacer structure. We will describe our experimental efforts to understand and quantify the behavior of different materials and also discuss a first investigation of a specific on-axis SiC telescope spacer for LISA. This work is supported by NASA contract 00069955.

  9. Total hip arthroplasty.

    PubMed Central

    Siopack, J S; Jergesen, H E

    1995-01-01

    Total hip arthroplasty, or surgical replacement of the hip joint with an artificial prosthesis, is a reconstructive procedure that has improved the management of those diseases of the hip joint that have responded poorly to conventional medical therapy. In this review we briefly summarize the evolution of total hip arthroplasty, the design and development of prosthetic hip components, and the current clinical indications for this procedure. The possible complications of total hip arthroplasty, its clinical performance over time, and future directions in hip replacement surgery are also discussed. Images PMID:7725707

  10. Probabilistic models for CRISPR spacer content evolution

    PubMed Central

    2013-01-01

    Background The CRISPR/Cas system is known to act as an adaptive and heritable immune system in Eubacteria and Archaea. Immunity is encoded in an array of spacer sequences. Each spacer can provide specific immunity to invasive elements that carry the same or a similar sequence. Even in closely related strains, spacer content is very dynamic and evolves quickly. Standard models of nucleotide evolution cannot be applied to quantify its rate of change since processes other than single nucleotide changes determine its evolution. Methods We present probabilistic models that are specific for spacer content evolution. They account for the different processes of insertion and deletion. Insertions can be constrained to occur on one end only or are allowed to occur throughout the array. One deletion event can affect one spacer or a whole fragment of adjacent spacers. Parameters of the underlying models are estimated for a pair of arrays by maximum likelihood using explicit ancestor enumeration. Results Simulations show that parameters are well estimated on average under the models presented here. There is a bias in the rate estimation when including fragment deletions. The models also estimate times between pairs of strains. But with increasing time, spacer overlap goes to zero, and thus there is an upper bound on the distance that can be estimated. Spacer content similarities are displayed in a distance based phylogeny using the estimated times. We use the presented models to analyze different Yersinia pestis data sets and find that the results among them are largely congruent. The models also capture the variation in diversity of spacers among the data sets. A comparison of spacer-based phylogenies and Cas gene phylogenies shows that they resolve very different time scales for this data set. Conclusions The simulations and data analyses show that the presented models are useful for quantifying spacer content evolution and for displaying spacer content similarities of closely related strains in a phylogeny. This allows for comparisons of different CRISPR arrays or for comparisons between CRISPR arrays and nucleotide substitution rates. PMID:23442002

  11. Prospective study comparing functional outcomes and revision rates between hip resurfacing and total hip arthroplasty: preliminary results for 2 years.

    PubMed

    Pailh, Rgis; Reina, Nicolas; Cavaignac, Etienne; Sharma, Akash; Lafontan, Valrie; Laffosse, Jean-Michel; Chiron, Philippe

    2013-01-01

    There is a need of independent prospective studies about modern generation of hip resurfacing implants. The aim of this propective observational study was to compare the functional outcomes and revision rates with hip resurfacing arthroplasty and total hip arthroplasty and to present the preliminary results at 2 years. Patients included were recruited prospectively in the Partial Pelvic Replacement Hip Project by a single surgeon between January 2007 and January 2010. Patients were assessed with the Harris Hip Score (HHS) and Postel-Merle d'Aubign (MDA) score and Devane Score. The end point of the study was reoperation for any cause related to the prosthesis. At a mean follow up of 38.6 months there were a total of 142 patients with hip resurfacing (group 1) [100 Durom() (Zimmer Inc., Warsaw, IN, USA) and 42 Birmingham Hip Resurfacing() (Smith & Nephew, Memphis, TN, USA)] and 278 patients with total hip arthroplasty (group 2). The results showed significantly greater gain of HHS, MDA and Devane score with hip resurfacing procedures. However, considering all the complications, the rate was significantly higher in group 16.4% vs 1.79% in group 2 (P<0.0001). In group 1 we observed 6 complications only concerned males with Durom() implants. The follow up of this cohort is still on going and may deliver more information on the evolution of these results in time. PMID:24191180

  12. Prospective Study Comparing Functional Outcomes and Revision Rates Between Hip Resurfacing and Total Hip Arthroplasty: Preliminary Results for 2 Years

    PubMed Central

    Pailh, Rgis; Reina, Nicolas; Cavaignac, Etienne; Sharma, Akash; Lafontan, Valrie; Laffosse, Jean-Michel; Chiron, Philippe

    2013-01-01

    There is a need of independent prospective studies about modern generation of hip resurfacing implants. The aim of this propective observational study was to compare the functional outcomes and revision rates with hip resurfacing arthroplasty and total hip arthroplasty and to present the preliminary results at 2 years. Patients included were recruited prospectively in the Partial Pelvic Replacement Hip Project by a single surgeon between January 2007 and January 2010. Patients were assessed with the Harris Hip Score (HHS) and Postel-Merle dAubign (MDA) score and Devane Score. The end point of the study was reoperation for any cause related to the prosthesis. At a mean follow up of 38.6 months there were a total of 142 patients with hip resurfacing (group 1) [100 Durom (Zimmer Inc., Warsaw, IN, USA) and 42 Birmingham Hip Resurfacing (Smith & Nephew, Memphis, TN, USA)] and 278 patients with total hip arthroplasty (group 2). The results showed significantly greater gain of HHS, MDA and Devane score with hip resurfacing procedures. However, considering all the complications, the rate was significantly higher in group 16.4% vs 1.79% in group 2 (P<0.0001). In group 1 we observed 6 complications only concerned males with Durom implants. The follow up of this cohort is still on going and may deliver more information on the evolution of these results in time. PMID:24191180

  13. Performance analysis of total hip prostheses: some particular metallurgical observations.

    PubMed

    Ducheyne, P; De Meester, P; Aernoudt, E

    1980-01-01

    Metallurgical observations of phenomena which influence the clinically successful performance of permanent implants and implant materials are reported. The effect of casting voids in cast cobalt chromium femoral stems of total hip replacements is discussed first. Pitting corrosion occurred in a retrieved stainless-steel implant type AISI 316 containing 2.7% Mo. The fractographic pattern of this device retrieved for fatigue failure shows typical characteristics of corrosion-enhanced fatigue. PMID:7358739

  14. Current role of spacers for prostate cancer radiotherapy

    PubMed Central

    Pinkawa, Michael

    2015-01-01

    Radiotherapy is an established curative treatment method for prostate cancer. Optimal tumor control rates can only be achieved with high local doses, associated with a considerable risk of rectal toxicity. Apart from already widely adapted technical advances, as intensity-modulated radiation therapy, the application of spacers placed between the prostate and rectum has been increasingly used in the last years. Biodegradable spacers, including hydrogel, hyaluronic acid, collagen or an implantable balloon, can be injected or inserted in a short procedure under transrectal ultrasound guidance via a transperineal approach. A distance of about 1.0-1.5 cm is usually achieved between the rectum and prostate, excluding the rectal wall from the high isodoses. Several studies have shown well tolerated injection procedures and treatments. Apart from considerable reduction of rectal irradiation, a prospective randomized trial demonstrated a reduction of rectal toxicity after hydrogel injection in men undergoing prostate image-guided intensity-modulated radiation therapy. The results are encouraging for continuing evaluation in dose escalation, hypofractionation, stereotactic radiotherapy or re-irradiation trials in the future. PMID:26677428

  15. Hydrogel Spacer Prospective Multicenter Randomized Controlled Pivotal Trial: Dosimetric and Clinical Effects of Perirectal Spacer Application in Men Undergoing Prostate Image Guided Intensity Modulated Radiation Therapy

    SciTech Connect

    Mariados, Neil; Sylvester, John; Shah, Dhiren; Karsh, Lawrence; Hudes, Richard; Beyer, David; Kurtzman, Steven; Bogart, Jeffrey; Hsi, R. Alex; Kos, Michael; Ellis, Rodney; Logsdon, Mark; Zimberg, Shawn; Forsythe, Kevin; Zhang, Hong; Soffen, Edward; Francke, Patrick; Mantz, Constantine; Rossi, Peter; DeWeese, Theodore; and others

    2015-08-01

    Purpose: Perirectal spacing, whereby biomaterials are placed between the prostate and rectum, shows promise in reducing rectal dose during prostate cancer radiation therapy. A prospective multicenter randomized controlled pivotal trial was performed to assess outcomes following absorbable spacer (SpaceOAR system) implantation. Methods and Materials: Overall, 222 patients with clinical stage T1 or T2 prostate cancer underwent computed tomography (CT) and magnetic resonance imaging (MRI) scans for treatment planning, followed with fiducial marker placement, and were randomized to receive spacer injection or no injection (control). Patients received postprocedure CT and MRI planning scans and underwent image guided intensity modulated radiation therapy (79.2 Gy in 1.8-Gy fractions). Spacer safety and impact on rectal irradiation, toxicity, and quality of life were assessed throughout 15 months. Results: Spacer application was rated as “easy” or “very easy” 98.7% of the time, with a 99% hydrogel placement success rate. Perirectal spaces were 12.6 ± 3.9 mm and 1.6 ± 2.0 mm in the spacer and control groups, respectively. There were no device-related adverse events, rectal perforations, serious bleeding, or infections within either group. Pre-to postspacer plans had a significant reduction in mean rectal V70 (12.4% to 3.3%, P<.0001). Overall acute rectal adverse event rates were similar between groups, with fewer spacer patients experiencing rectal pain (P=.02). A significant reduction in late (3-15 months) rectal toxicity severity in the spacer group was observed (P=.04), with a 2.0% and 7.0% late rectal toxicity incidence in the spacer and control groups, respectively. There was no late rectal toxicity greater than grade 1 in the spacer group. At 15 months 11.6% and 21.4% of spacer and control patients, respectively, experienced 10-point declines in bowel quality of life. MRI scans at 12 months verified spacer absorption. Conclusions: Spacer application was well tolerated. Increased perirectal space reduced rectal irradiation, reduced rectal toxicity severity, and decreased rates of patients experiencing declines in bowel quality of life. The spacer appears to be an effective tool, potentially enabling advanced prostate RT protocols.

  16. Outcome of total knee replacement following explantation and cemented spacer therapy

    PubMed Central

    Ghanem, Mohamed; Zajonz, Dirk; Bollmann, Juliane; Geissler, Vanessa; Prietzel, Torsten; Moche, Michael; Roth, Andreas; Heyde, Christoph-E.; Josten, Christoph

    2016-01-01

    Background: Infection after total knee replacement (TKR) is one of the serious complications which must be pursued with a very effective therapeutic concept. In most cases this means revision arthroplasty, in which one-setting and two-setting procedures are distinguished. Healing of infection is the conditio sine qua non for re-implantation. This retrospective work presents an assessment of the success rate after a two-setting revision arthroplasty of the knee following periprosthetic infection. It further considers drawing conclusions concerning the optimal timing of re-implantation. Patients and methods: A total of 34 patients have been enclosed in this study from September 2005 to December 2013. 35 re-implantations were carried out following explantation of total knee and implantation of cemented spacer. The patient’s group comprised of 53% (18) males and 47% (16) females. The average age at re-implantation time was 72.2 years (ranging from 54 to 85 years). We particularly evaluated the microbial spectrum, the interval between explantation and re-implantation, the number of surgeries that were necessary prior to re-implantation as well as the postoperative course. Results: We reported 31.4% (11) reinfections following re-implantation surgeries. The number of the reinfections declined with increasing time interval between explantation and re-implantation. Patients who developed reinfections were operated on (re-implantation) after an average of 4.47 months. Those patients with uncomplicated course were operated on (re-implantation) after an average of 6.79 months. Nevertheless, we noticed no essential differences in outcome with regard to the number of surgeries carried out prior to re-implantation. Mobile spacers proved better outcome than temporary arthrodesis with intramedullary fixation. Conclusion: No uniform strategy of treatment exists after peri-prosthetic infections. In particular, no optimal timing can be stated concerning re-implantation. Our data point out to the fact that a longer time interval between explantation and re-implantation reduces the rate of reinfection. From our point of view, the optimal timing for re-implantation depends on various specific factors and therefore it should be defined individually. PMID:27066391

  17. Engineered porous metals for implants

    NASA Astrophysics Data System (ADS)

    Vamsi Krishna, B.; Xue, Weichang; Bose, Susmita; Bandyopadhyay, Amit

    2008-05-01

    Interest is significant in patient-specific implants with the possibility of guided tissue regeneration, particularly for load-bearing implants. For such implants to succeed, novel design approaches and fabrication technologies that can achieve balanced mechanical and functional performance in the implants are necessary. This article is focused on porous load-bearing implants with tailored micro-as well as macrostructures using laser-engineered net shaping (LENS™), a solid freeform fabrication or rapid prototyping technique that can be used to manufacture patient-specific implants. This review provides an insight into LENS, some properties of porous metals, and the potential applications of this process to fabricate unitized structures which can eliminate longstanding challenges in load-bearing implants to increase their in-vivo lifetime, such as in a total hip prosthesis.

  18. Novel Highly Porous Metal Technology in Artificial Hip and Knee Replacement: Processing Methodologies and Clinical Applications

    NASA Astrophysics Data System (ADS)

    Muth, John; Poggie, Matthew; Kulesha, Gene; Michael Meneghini, R.

    2013-02-01

    Hip and knee replacement can dramatically improve a patient's quality of life through pain relief and restored function. Fixation of hip and knee replacement implants to bone is critical to the success of the procedure. A variety of roughened surfaces and three-dimensional porous surfaces have been used to enhance biological fixation on orthopedic implants. Recently, highly porous metals have emerged as versatile biomaterials that may enhance fixation to bone and are suitable to a number of applications in hip and knee replacement surgery. This article provides an overview of several processes used to create these implant surfaces.

  19. Hip replacement - discharge

    MedlinePlus

    ... or part of your hip joint with an artificial joint. This artificial joint is called a prosthesis. ... be careful that you do not dislocate your artificial hip, especially in the first few months after ...

  20. Hip joint injection

    MedlinePlus

    ... injection is a shot of medicine into the hip joint. The medicine helps relieve pain and inflammation. It ... often caused by: Bursitis Arthritis Injury to the hip joint or surrounding area Overuse or strain from running ...

  1. Hip fracture surgery

    MedlinePlus

    ... neck fracture repair; Trochanteric fracture repair; Hip pinning surgery; Osteoarthritis-hip ... You may receive general anesthesia before this surgery. This means ... spinal anesthesia. With this kind of anesthesia, medicine is ...

  2. Hip Injuries and Disorders

    MedlinePlus

    ... or falling can all sometimes lead to hip injuries. These include Strains Bursitis Dislocations Fractures Certain diseases also lead to hip injuries or problems. Osteoarthritis can cause pain and limited ...

  3. The ribosomal gene spacer region in archaebacteria

    NASA Technical Reports Server (NTRS)

    Achenbach-Richter, L.; Woese, C. R.

    1988-01-01

    Sequences for the spacer regions that separate the 16S and 23S ribosomal RNA genes have been determined for four more (strategically placed) archaebacteria. These confirm the general rule that methanogens and extreme halophiles have spacers that contain a single tRNAala gene, while tRNA genes are not found in the spacer region of the true extreme thermophiles. The present study also shows that the spacer regions from the sulfate reducing Archaeglobus and the extreme thermophile Thermococcus (both of which cluster phylogenetically with the methanogens and extreme halophiles) contain each a tRNAala gene. Thus, not only all methanogens and extreme halophiles show this characteristic, but all organisms on the "methanogen branch" of the archaebacterial tree appear to do so. The finding of a tRNA gene in the spacer region of the extreme thermophile Thermococcus celer is the first known phenotypic property that links this organism with its phylogenetic counterparts, the methanogens, rather than with its phenotypic counterparts, the sulfur-dependent extreme thermophiles.

  4. Ultrasound: Infant Hip

    MedlinePlus

    ... Caring for Your Child All About Food Allergies Ultrasound: Infant Hip KidsHealth > For Parents > Ultrasound: Infant Hip Print A A A Text Size ... español Ultrasonido: cadera What It Is A hip ultrasound is a safe and painless test that uses ...

  5. Metal-on-Metal Hip Resurfacing Arthroplasty

    PubMed Central

    Sehatzadeh, S; Kaulback, K; Levin, L

    2012-01-01

    Background Metal-on-metal (MOM) hip resurfacing arthroplasty (HRA) is in clinical use as an appropriate alternative to total hip arthroplasty in young patients. In this technique, a metal cap is placed on the femoral head to cover the damaged surface of the bone and a metal cup is placed in the acetabulum. Objectives The primary objective of this analysis was to compare the revision rates of MOM HRA using different implants with the benchmark set by the National Institute of Clinical Excellence (NICE). The secondary objective of this analysis was to review the literature regarding adverse biological effects associated with implant material. Review Methods A literature search was performed on February 13, 2012, to identify studies published from January 1, 2009, to February 13, 2012. Results The revision rates for MOM HRA using 6 different implants were reviewed. The revision rates for MOM HRA with 3 implants met the NICE criteria, i.e., a revision rate of 10% or less at 10 years. Two implants had short-term follow-ups and MOM HRA with one of the implants failed to meet the NICE criteria. Adverse tissue reactions resulting in failure of the implants have been reported by several studies. With a better understanding of the factors that influence the wear rate of the implants, adverse tissue reactions and subsequent implant failure can be minimized. Many authors have suggested that patient selection and surgical technique affect the wear rate and the risk of tissue reactions. The biological effects of high metal ion levels in the blood and urine of patients with MOM HRA implants are not known. Studies have shown an increase in chromosomal aberrations in patients with MOM articulations, but the clinical implications and long-term consequences of this increase are still unknown. Epidemiological studies have shown that patients with MOM HRA implants did not have an overall increase in mortality or risk of cancer. There is insufficient clinical data to confirm the teratogenicity of MOM implants in humans. Conclusions Metal-on-metal HRA can be beneficial for appropriately selected patients, provided the surgeon has the surgical skills required for performing this procedure. Plain Language Summary There are many young patients with hip diseases who need to have hip replacement surgery. Although a traditional hip replacement is an acceptable procedure for these patients, some surgeons prefer using a newer technique in young patients called hip resurfacing. In this technique, instead of removing the head of the femoral bone, a metal cap is placed on the femoral head to cover the damaged surface of the bone and a metal cup is placed in the hip socket, similar to the cups used in traditional hip replacement. The analysis of the revision rates (i.e., how soon and in how many patients the surgery needs to be redone) and safety of resurfacing implants showed that generally these implants can last 10 years or more for the majority of young people. Good outcomes can be expected when skilled surgeons perform the surgery in properly selected patients. However, since these implants are made of metal (cobalt and chromium alloy), there is concern about excess metal debris production due to friction between the 2 metal components leading to high levels of metal ions in the blood and urine of patients. The production of metal debris may result in inflammation in the joint or development of a benign soft tissue mass leading to implant failure. However, it has been shown that this risk can be reduced by proper positioning of the implant and the careful selection of patients for this procedure. Little is known about the long-term biological effects of high levels of metal ions in the blood and urine of patients who have received metal implants. There is concern about potential increases in the risk of cancer and the risk of fetal abnormalities, but these effects have not been established yet. However, since cobalt and chromium can pass the placental barrier, implants that are not metal-on-metal are recommended for women at childbearing ages if they need a hip replacement. PMID:23074429

  6. Robot-assisted total hip arthroplasty.

    PubMed

    Banerjee, Samik; Cherian, Jeffery J; Elmallah, Randa K; Pierce, Todd P; Jauregui, Julio J; Mont, Michael A

    2016-01-01

    Precise and accurate biomechanical reconstruction during total hip arthroplasty (THA) is essential for durable long-term survivorship. Accurate fit of cementless hip implants is also crucial to reduce micromotion between the bone-implant interfaces to allow for stable osseointegration. Robotic technology aims to minimize potential human errors and improve implant alignment and fit, and address persisting concerns with modern-day cementless THA. Although robotic THA dates back to the early 1990s, concerns with increased operating times, costs, and complications led to its withdrawal. However, semi-active systems have renewed interest in robot-assisted joint arthroplasty. We reviewed the current technology, its potential benefits, and the reported clinical and radiographic outcomes. Early evidence suggests that robotic use may lead to more accurate reconstruction of radiographic parameters, such as implant positioning, fit, center-of-rotation, and leg-length discrepancy. Further research is needed to determine if these will translate into better outcomes and improved implant longevity to justify increased costs. PMID:26592900

  7. [History of hip arthroplasty].

    PubMed

    P?omi?ski, Janusz; Kwiatkowski, Krzysztof

    2007-02-01

    The authors present the history of hip prosthesis in treatment of coxarthrosis. Despite eighty years of experience the problem of gaining good and long-term results still exist and is difficult to solve. Even changing the way on cementless stabilization of prosthesis doesn't has result in solving the problem of aseptic loosening of hip arthroplasty. Problems of wear derbies made the producers find new to reduce particulate debris. The future of hip arthroplasty is connected with hip resurfacing. Moreover, the higher number of primary hip plasty the more prosthesis are loosening. The treatment is far more difficult and more expensive. PMID:17598648

  8. Analysis of bioglass fixation of hip prostheses.

    PubMed

    Hench, L L; Pantano, C G; Buscemi, P J; Greenspan, D C

    1977-03-01

    The analysis of the bonding interface between hip prostheses and bone after functional use in animals was carried out. Scanning electron microscopy (SEM) with energy dispersive analysis (EDX), and Auger electron spectroscopy were used to evaluate the bonding interface. Various methods of postsacrifice sample preparation were used to evaluate the effect of such different methods on the analysis of the bonding interface. Comparison of the results with several rat tibia implant experiments is also presented. PMID:404298

  9. Total Hip Joint Replacement Biotelemetry System

    NASA Technical Reports Server (NTRS)

    Boreham, J. F.; Postal, R. B.; Luntz, R. A.

    1981-01-01

    The development of a biotelemetry system that is hermetically sealed within a total hip replacement implant is reported. The telemetry system transmits six channels of stress data to reconstruct the major forces acting on the neck of the prosthesis and uses an induction power coupling technique to eliminate the need for internal batteries. The activities associated with the telemetry microminiaturization, data recovery console, hardware fabrications, power induction systems, electrical and mechanical testing and hermetic sealing test results are discussed.

  10. Hip resurfacing arthroplasty

    PubMed Central

    2010-01-01

    Background and purpose Hip resurfacing arthroplasty is claimed to allow higher activity levels and to give better quality of life than total hip arthroplasty. In this literature review, we assessed the therapeutic value of hip resurfacing arthroplasty as measured by functional outcome. Methods An extensive literature search was performed using the PubMed, Embase, and Cochrane databases. Results 9 patient series, 1 case-control study, and 1 randomized controlled trial (RCT) were included. Clinically and statistically significant improvement in sporting activity and hip scores were found in 10 studies. Interpretation Studies with low levels of evidence have shown improvement in various different hip scores and one RCT showed better outcomes with hip resurfacing arthroplasty. There is no high-level evidence to prove that there is improved clinical outcome using hip resurfacing arthroplasty. More randomized research needs to be done. PMID:20860440

  11. Hip resurfacing in a district general hospital: 6-year clinical results using the ReCap hip resurfacing system

    PubMed Central

    2012-01-01

    Background The purpose of our study was to prospectively report the clinical results of 280 consecutive hips (240 patients) who received a ReCap Hip Resurfacing System implant (Biomet Inc., Warsaw, USA) in a single district general hospital. Literature reports a large variation in clinical results between different resurfacing designs and published results using this particular design are scarce. Methods Mean follow up was 3.3 years (1.0 to 6.3) and four patients were lost to follow-up. All patients were diagnosed with end-stage hip osteoarthritis, their mean age was 54 years and 76.4% of all patients were male. Results There were 16 revisions and four patients reported a Harris Hip Score <70 points at their latest follow up. There were no pending revisions. Kaplan-Meier implant survival probability, with revision for any reason as endpoint, was 93.5% at six years follow-up (95%-CI: 88.8-95.3). There were no revisions for Adverse Reactions to Metal Debris (ARMD) and no indications of ARMD in symptomatic non-revised patients, although diagnostics were limited to ultrasound scans. Conclusions This independent series confirms that hip resurfacing is a demanding procedure, and that implant survival of the ReCap hip resurfacing system is on a critical level in our series. In non-revised patients, reported outcomes are generally excellent. Trial registration ClinicalTrials.gov Identifier: NCT00603395 PMID:23234268

  12. Indirect decompression and vertebral body endplate strength after lateral interbody spacer impaction: cadaveric and foam-block models.

    PubMed

    Kwon, Anthony J; Hunter, William D; Moldavsky, Mark; Salloum, Kanaan; Bucklen, Brandon

    2016-05-01

    OBJECTIVE The lateral transpsoas approach to the lumbar spine is a well-defined procedure for the management of discogenic spinal pathology necessitating surgical intervention. Intervertebral device subsidence is a postoperative clinical risk that can lead to recurrence of symptomatic pathology and the need for surgical reintervention. The current study was designed to investigate static versus expandable lateral intervertebral spacers in indirect decompression for preserving vertebral body endplate strength. METHODS Using a cadaveric biomechanical study and a foam-block vertebral body model, researchers compared vertebral body endplate strength and distraction potential. Fourteen lumbar motion segments (7 L2-3 and 7 L4-5 specimens) were distributed evenly between static and expandable spacer groups. In each specimen discectomy was followed by trialing and spacer impaction. Motion segments were axially sectioned through the disc, and a metal stamp was used to apply a compressive load to superior and inferior vertebral bodies to quantify endplate strength. A paired, 2-sample for means t-test was performed to determine statistically significant differences between groups (p ≤ 0.05). A foam-block endplate model was used to control simulated disc tension when a spacer with 2- and 3-mm desired distraction was inserted. One-way ANOVA and a post hoc Student Newman-Keuls test were performed (p ≤ 0.05) to determine differences in distraction. RESULTS Both static and expandable spacers restored intact neural foramen and disc heights after device implantation (p > 0.05). Maximum peak loads at endplate failure for static and expandable spacers were 1764 N (± 966 N) and 2284 N (± 949 N), respectively (p ≤ 0.05). The expandable spacer consistently produced greater desired distraction than was created by the static spacer in the foam-block model (p ≤ 0.05). Distraction created by fully expanding the spacer was significantly greater than the predetermined goals of 2 mm and 3 mm (p ≤ 0.05). CONCLUSIONS The current investigation shows that increased trialing required for a static spacer may lead to additional iatrogenic endplate damage, resulting in less distraction and increased propensity for postoperative implant subsidence secondary to endplate disruption. PMID:26824583

  13. Trajectories of depressive symptoms after hip fracture

    PubMed Central

    Cristancho, P.; Lenze, E. J.; Avidan, M. S.; Rawson, K. S.

    2016-01-01

    Background Hip fracture is often complicated by depressive symptoms in older adults. We sought to characterize trajectories of depressive symptoms arising after hip fracture and examine their relationship with functional outcomes and walking ability. We also investigated clinical and psychosocial predictors of these trajectories. Method We enrolled 482 inpatients, aged ≥60 years, who were admitted for hip fracture repair at eight St Louis, MO area hospitals between 2008 and 2012. Participants with current depression diagnosis and/or notable cognitive impairment were excluded. Depressive symptoms and functional recovery were assessed with the Montgomery–Asberg Depression Rating Scale and Functional Recovery Score, respectively, for 52 weeks after fracture. Health, cognitive, and psychosocial variables were gathered at baseline. We modeled depressive symptoms using group-based trajectory analysis and subsequently identified correlates of trajectory group membership. Results Three trajectories emerged according to the course of depressive symptoms, which we termed ‘resilient’, ‘distressed’, and ‘depressed’. The depressed trajectory (10% of participants) experienced a persistently high level of depressive symptoms and a slower time to recover mobility than the other trajectory groups. Stressful life events prior to the fracture, current smoking, higher anxiety, less social support, antidepressant use, past depression, and type of implant predicted membership of the depressed trajectory. Conclusions Depressive symptoms arising after hip fracture are associated with poorer functional status. Clinical and psychosocial variables predicted membership of the depression trajectory. Early identification and intervention of patients in a depressive trajectory may improve functional outcomes after hip fracture. PMID:27032698

  14. Separator-spacer for electrochemical systems

    DOEpatents

    Grimes, Patrick G.; Einstein, Harry; Newby, Kenneth R.; Bellows, Richard J.

    1983-08-02

    An electrochemical cell construction features a novel co-extruded plastic electrode in an interleaved construction with a novel integral separator-spacer. Also featured is a leak and impact resistant construction for preventing the spill of corrosive materials in the event of rupture.

  15. The World Hip Trauma Evaluation Study 3

    PubMed Central

    Parsons, N.; Achten, J.; Griffin, X. L.; Costa, M. L.; Reed, M. R.

    2016-01-01

    Background Approximately half of all hip fractures are displaced intracapsular fractures. The standard treatment for these fractures is either hemiarthroplasty or total hip arthroplasty. The recent National Institute for Health and Care Excellence (NICE) guidance on hip fracture management recommends the use of ‘proven’ cemented stem arthroplasty with an Orthopaedic Device Evaluation Panel (ODEP) rating of at least 3B (97% survival at three years). The Thompsons prosthesis is currently lacking an ODEP rating despite over 50 years of clinical use, likely due to the paucity of implant survival data. Nationally, adherence to these guidelines is varied as there is debate as to which prosthesis optimises patient outcomes. Design This study design is a multi-centre, multi-surgeon, parallel, two arm, standard-of-care pragmatic randomised controlled trial. It will be embedded within the WHiTE Comprehensive Cohort Study (ISRCTN63982700). The main analysis is a two-way equivalence comparison between Hemi-Thompson and Hemi-Exeter polished taper with Unitrax head. Secondary outcomes will include radiological leg length discrepancy measured as per Bidwai and Willett, mortality, re-operation rate and indication for re-operation, length of index hospital stay and revision at four months. This study will be supplemented by the NHFD (National Hip Fracture Database) dataset. Discussion Evidence on the optimum choice of prosthesis for hemiarthroplasty of the hip is lacking. National guidance is currently based on expert opinion rather than empirical evidence. The incidence of hip fracture is likely to continue to increase and providing high quality evidence on the optimum Cite this article: A. L. Sims. The World Hip Trauma Evaluation Study 3: Hemiarthroplasty Evaluation by Multicentre Investigation – WHITE 3: HEMI – An Abridged Protocol. Bone Joint Res 2016;5:18–25. DOI: 10.1302/2046-3758.51.2000473 PMID:26825319

  16. Cortical bone facet spacers for cervical spine decompression: effects on intervertebral kinetics and foraminal area.

    PubMed

    Maulucci, Christopher M; Sansur, Charles A; Singh, Vaneet; Cholewczynski, Alexandra; Shetye, Snehal S; McGilvray, Kirk; Puttlitz, Christian M

    2016-01-01

    OBJECT Nerve root decompression to relieve pain and radiculopathy remains one of the main goals of fusion-promoting procedures in the subaxial cervical spine. The use of allograft facet spacers has been suggested as a potential alternative for performing foraminotomies to increase the space available for the cervical nerve roots while providing segmental stiffening. Therefore, the goal of this cadaveric biomechanical study was to determine the acute changes in kinetics and foraminal area after the insertion of cortical bone facet spacers into the subaxial cervical spine. METHODS Allograft spacers (2 mm in height) were placed bilaterally into cadaveric cervical spine specimens (C2-T1, age of donors 57.5 9.5 years, n = 7) at 1 (C4-5) and 3 (C3-6) levels with and without laminectomies and posterior lateral mass screw fixation. Standard stereophotogrammetry under pure moment loading was used to assess spinal kinetics. In addition, the authors performed 3D principal component analysis of CT scans to determine changes in foraminal cross-sectional area (FCSA) available for the spinal nerve roots. RESULTS Generally, the introduction of 2-mm-height facet spacers to the cervical spine produced mild, statistically insignificant reductions in motion with particular exceptions at the levels of implantation. No significant adjacent-level motion effects in any bending plane were observed. The addition of the posterior instrumentation (PI) to the intact spines resulted in statistically significant reductions in motion at all cervical levels and bending planes. The same kinetic results were obtained when PI was added to spines that also had facet spacers at 3 levels and spines that had been destabilized by en bloc laminectomy. The addition of 2-mm facet spacers at C3-4, C4-5, and C5-6 did produce statistically significant increases in FCSA at those levels. CONCLUSIONS The addition of allograft cervical facet spacers should be considered a potential option to accomplish indirect foraminal decompression as measured in this cadaveric biomechanical study. However, 2-mm spacers without supplemental instrumentation do not provide significantly increased spinal segmental stability. PMID:26407085

  17. 21 CFR 888.3340 - Hip joint metal/composite semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... cemented prosthesis. 888.3340 Section 888.3340 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Hip joint metal/composite semi-constrained cemented prosthesis. (a) Identification. A hip joint metal/composite semi-constrained cemented prosthesis is a two-part device intended to be implanted to replace...

  18. 21 CFR 888.3300 - Hip joint metal constrained cemented or uncemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... prosthesis. 888.3300 Section 888.3300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... metal constrained cemented or uncemented prosthesis. (a) Identification. A hip joint metal constrained cemented or uncemented prosthesis is a device intended to be implanted to replace a hip joint. The...

  19. 21 CFR 888.3340 - Hip joint metal/composite semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... cemented prosthesis. 888.3340 Section 888.3340 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Hip joint metal/composite semi-constrained cemented prosthesis. (a) Identification. A hip joint metal/composite semi-constrained cemented prosthesis is a two-part device intended to be implanted to replace...

  20. 21 CFR 888.3300 - Hip joint metal constrained cemented or uncemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... prosthesis. 888.3300 Section 888.3300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... metal constrained cemented or uncemented prosthesis. (a) Identification. A hip joint metal constrained cemented or uncemented prosthesis is a device intended to be implanted to replace a hip joint. The...

  1. 21 CFR 888.3300 - Hip joint metal constrained cemented or uncemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... prosthesis. 888.3300 Section 888.3300 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND... metal constrained cemented or uncemented prosthesis. (a) Identification. A hip joint metal constrained cemented or uncemented prosthesis is a device intended to be implanted to replace a hip joint. The...

  2. 21 CFR 888.3340 - Hip joint metal/composite semi-constrained cemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... cemented prosthesis. 888.3340 Section 888.3340 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Hip joint metal/composite semi-constrained cemented prosthesis. (a) Identification. A hip joint metal/composite semi-constrained cemented prosthesis is a two-part device intended to be implanted to replace...

  3. Histrelin Implant

    MedlinePlus

    ... think you have become pregnant while receiving histrelin implant, call your doctor immediately. Histrelin implant can harm the ... an implant of histrelin or to have histrelin implant removed, you should call your healthcare provider right away to reschedule your ...

  4. Metal-on-Metal Total Hip Arthroplasty: Patient Evaluation and Treatment.

    PubMed

    Bolognesi, Michael P; Ledford, Cameron K

    2015-12-01

    Metal-on-metal (MoM) hip articulations were thought to represent a biologic and biomechanically favorable alternative to conventional metal-on-polyethylene total hip arthroplasty implants. However, concerns emerged when registry data reported significantly higher failure rates associated with MoM implants compared with other contemporary hip implants. These high implant failure rates have been attributed to the release of metal particles into the periprosthetic space, creating macroscopic necrosis; corrosive osteolysis; large, sterile hip effusions; and periprosthetic solid and cystic masses (ie, pseudotumors)-a spectrum of findings termed adverse reaction to metal debris. A thorough clinical history and physical examination, along with laboratory data and imaging surveillance of these patients, is critical for appropriate diagnosis and treatment. The decision to perform revision hip arthroplasty of a metal-on-metal implant is multifactorial and should be based on documented, objective clinical indications. A systematic and objective approach to this evaluation and treatment is essential to optimize the care of patients who undergo total hip arthroplasty with MoM implants. PMID:26493972

  5. Dementia and Hip Fractures

    PubMed Central

    Friedman, Susan M.; Menzies, Isaura B.; Bukata, Susan V.; Mendelson, Daniel A.; Kates, Stephen L.

    2010-01-01

    Dementia and hip fractures are 2 conditions that are seen primarily in older adults, and both are associated with substantial morbidity and mortality. An individual with dementia is up to 3 times more likely than a cognitively intact older adult to sustain a hip fracture. This may occur via several mechanisms, including (1) risk factors that are common to both outcomes; (2) the presence of dementia increasing hip fracture incidence via intermediate risk factors, such as falls, osteoporosis, and vitamin D; and (3) treatment of dementia causing side effects that increase hip fracture risk. We describe a model that applies these 3 mechanisms to explain the relationship between dementia and hip fractures. Comprehensive understanding of these pathways and their relative influence on the outcome of hip fracture will guide the development of effective interventions and potentially improve prevention efforts. PMID:23569663

  6. Migration analysis of a metaphyseal anchored short-stem hip prosthesis

    PubMed Central

    2012-01-01

    Background and purpose Metaphyseal anchored short-stem hip implants were designed to improve load transmission and preserve femoral bone stock. Until now, only few outcome data have been available and migration studies are one of the few ways of obtaining data that are predictive of implant survival. We therefore evaluated a metaphyseal anchored short-stem hip implant by Ein Bild Roentgen Analyse femoral component analysis (EBRA-FCA). Patients and methods First, the EBRA-FCA method was validated for the short-stem hip implant. Then 80 of the first 100 consecutive implants were evaluated after at least 2 years. Clinical assessment was performed using the WOMAC and the UCLA score. Results After 2.7 (2.0–4.2), years none of the implants had been revised and by that time the stems had subsided by a mean of 0.7 mm (SD 1.8) (95% CI: 0.3–1.1). Of the 80 implants, 78 were stable after 2 years, with 74 being primary stable and 4 showing secondary stabilization after initial subsidence. Continuous migration was seen in only 2 patients. The clinical outcome showed good results with a mean WOMAC of 11 (SD 13) and a mean UCLA score of 7.3 (SD 2.0). [OK?] Interpretation The metaphyseal anchored short-stem hip implant showed good functional results and a high degree of stability after 2 years. The outcome is comparable to that of clinically proven conventional hip implants and if the results are confirmed by long-term studies, short-stem hip arthroplasty might be an alternative for young patients requiring hip replacement. PMID:22900913

  7. Topological optimization in hip prosthesis design.

    PubMed

    Fraldi, M; Esposito, L; Perrella, G; Cutolo, A; Cowin, S C

    2010-08-01

    With particular interest on total hip arthroplasty (THA), optimization of orthopedic prostheses is employed in this work to minimize the probability of implant failure or maximize prosthesis reliability. This goal is often identified with the reduction of stress concentrations at the interface between bone and these devices. However, aseptic loosening of the implant is mainly influenced by bone resorption phenomena revealed in some regions of the femur when a prosthesis is introduced. As a consequence, bone resorption appears due to stress shielding, that is to say the decrease of the stress level in the implanted femur caused by the significant load carrying of the prosthesis due to its higher stiffness. A maximum stiffness topological optimization-based (TO) strategy is utilized for non-linear static finite element (FE) analyses of the femur-implant assembly, with the goal of reducing stress shielding in the femur and to furnish guidelines for re-designing hip prostheses. This is accomplished by employing an extreme accuracy for both the three- dimensional reconstruction of the femur geometry and the material properties maps assigned as explicit functions of the local densities. PMID:20037769

  8. Hip pain in the young, active patient: surgical strategies.

    PubMed

    Bloomfield, Michael R; Erickson, Jill A; McCarthy, Joseph C; Mont, Michael A; Mulkey, Patrick; Peters, Christopher L; Pivec, Robert; Austin, Matthew S

    2014-01-01

    Hip disorders in young patients likely exist as a spectrum of prearthritic and arthritic conditions. With the increasing recognition of these disorders, surgical options are being popularized and more patients are being treated at a younger age. Hip surgeons must develop a careful set of evidenced-based indications and follow surgical outcomes in a rigorous, scientific manner. Hip arthroscopy can be used to successfully treat some hip disorders, including labral tears, with or without femoroacetabular impingement, resulting in mechanical symptoms. Long-term outcomes after arthroscopy are determined by the condition of the cartilage at the time of surgery. Patients with preoperative radiographic evidence of moderate to severe arthritis have poor outcomes when treated with arthroscopy. Open joint preservation procedures (including periacetabular osteotomy and surgical hip dislocation with osteochondroplasty) can be done in the absence of substantial arthritis to treat hip dysplasia, femoroacetabular impingement, and related conditions. The results of these procedures are good in appropriately selected patients at short-term to midterm follow-ups. In the presence of severe arthritis, joint replacement is the treatment of choice. Total hip arthroplasty using uncemented acetabular and femoral fixation provides reliable osseointegration; however, long-term results in young patients have historically been compromised by bearing surface wear, osteolysis, and component loosening. Contemporary, highly cross-linked polyethylene and ceramic-on-ceramic bearings have durable results, low complication rates, and offer the potential of long-term survivorship in this high-demand population. In general, metal-on-metal implants have higher complication rates versus other bearing surface options and should be avoided. The best results of hip resurfacing are seen in men younger than 55 years with large femoral head sizes. Although implant survivorship is comparable to that of total hip arthroplasty, the sequelae of metal wear debris continue to cause concern. PMID:24720303

  9. Transient Synovitis of the Hip

    MedlinePlus

    ... inflammation and swelling of the tissues around the hip joint. Usually only one hip is affected. This condition ... to reduce the swelling and inflammation around the hip joint. Your child's doctor will probably ask you to ...

  10. Developmental Dysplasia of the Hip

    MedlinePlus

    ... is a problem with the way a baby's hip joint forms before, during, or after birth — causing an unstable hip. In severe cases, the hip joint can dislocate or cause trouble walking. Mild cases ...

  11. What Is a Hip Replacement?

    MedlinePlus

    ... Hip Replacement Find a Clinical Trial Journal Articles Hip Replacement PDF Version Size: 123 KB Audio Version ... 9.4 MB November 2014 What Is a Hip Replacement? Fast Facts: An Easy-to-Read Series ...

  12. Tube support grid and spacer therefor

    DOEpatents

    Ringsmuth, Richard J.; Kaufman, Jay S.

    1986-01-01

    A tube support grid and spacers therefor provide radially inward preloading of heat exchange tubes to minimize stress upon base welds due to differential thermal expansion. The grid comprises a concentric series of rings and spacers with opposing concave sides for conforming to the tubes and V-shaped ends to provide resilient flexibility. The flexibility aids in assembly and in transmitting seismic vibrations from the tubes to a shroud. The tube support grid may be assembled in place to achieve the desired inwardly radial preloading of the heat exchange tubes. Tab and slot assembly further minimizes stresses in the system. The radii of the grid rings may be preselected to effect the desired radially inward preloading.

  13. Heterogeneous diversity of spacers within CRISPR

    NASA Astrophysics Data System (ADS)

    Deem, Michael; He, Jiankui

    2011-03-01

    Clustered regularly interspaced short palindromic repeats (CRISPR) in bacterial and archaeal DNA have recently been shown to be a new type of anti-viral immune system in these organisms. We here study the diversity of spacers in CRISPR under selective pressure. We propose a population dynamics model that explains the biological observation that the leader-proximal end of CRISPR is more diversified and the leader-distal end of CRISPR is more conserved. This result is shown to be in agreement with recent experiments. Our results show that the CRISPR spacer structure is influenced by and provides a record of the viral challenges that bacteria face. 1) J. He and M. W. Deem, Phys. Rev. Lett. 105 (2010) 128102

  14. Honeycomb spacer crush stength test results

    SciTech Connect

    Leader, D.R.

    1993-09-15

    This report discusses aluminum honeycomb spacers, which are used as an energy absorbent material in shipping packages for off site shipment of radioactive materials and which were ordered in two crush strengths, 1,000 psi and 2,000 psi for use in drop tests requested by the Packaging and Transportation group as part of the shipping container rectification process. Both the group as part of the shipping container rectification process. Both the vendor and the SRTC Materials Laboratory performed crush strength measurements on test samples made from the material used to fabricate the actual spacers. The measurements of crush strength made in the SRTC Materials Laboratory are within 100 psi of the measurements made by the manufacturer for all samples tested and all test measurements are within 10% of the specified crush strength, which is acceptable to the P&T group for the planned tests.

  15. Debris catching spring detent spacer grid

    SciTech Connect

    Hatfield, S.C.; Andrews, M.G.; Broders, R.P.

    1991-06-18

    This patent describes a nuclear reactor having fuel assemblies including an upper end fitting and a lower end fitting and spaced nuclear fuel rod spacer grids therebetween for supporting and spacing a plurality of elongated nuclear fuel rods, each of which includes a hollow active portion of nuclear fuel filled cladding intermediate the rod ends and a tapering end cap of solid materials with a circumferential groove on the rod end which first encounters reactor coolant flow, a tall spacer grid relative to the grids adjacent the active portion being means for capturing and retaining deleterious debris carried by reactor coolant before it enters the active region of a fuel assembly through solid end caps compartments' corners and creates fuel rod cladding damage.

  16. Improved nuclear fuel assembly grid spacer

    DOEpatents

    Marshall, John; Kaplan, Samuel

    1977-01-01

    An improved fuel assembly grid spacer and method of retaining the basic fuel rod support elements in position within the fuel assembly containment channel. The improvement involves attachment of the grids to the hexagonal channel and of forming the basic fuel rod support element into a grid structure, which provides a design which is insensitive to potential channel distortion (ballooning) at high fluence levels. In addition the improved method eliminates problems associated with component fabrication and assembly.

  17. Lower limb length and offset in total hip arthroplasty.

    PubMed

    Flecher, X; Ollivier, M; Argenson, J N

    2016-02-01

    Restoration of normal hip biomechanics is a key goal of total hip arthroplasty (THA) and favorably affects functional recovery. Furthermore, a major concern for both the surgeon and the patient is preservation or restoration of limb length equality, which must be achieved without compromising the stability of the prosthesis. Here, definitions are given for anatomic and functional limb length discrepancies and for femoral and hip offset, determined taking anteversion into account. Data on the influence of operated-limb length and offset on patient satisfaction, hip function, and prosthesis survival after THA are reviewed. Errors may adversely impact function, quality of life, and prosthetic survival and may also generate conflicts between the surgeon and patient. Surgeons rely on two- or three-dimensional preoperative templating and on intraoperative landmarks to manage offset and length. Accuracy can be improved by using computer-assisted planning or surgery and the more recently introduced EOS imaging system. The prosthetic's armamentarium now includes varus-aligned and lateralized implants, as well as implants with modular or custom-made necks, which allow restoration of the normal hip geometry, most notably in patients with coxa vara or coxa valga. Femoral anteversion must also receive careful attention. The most common errors are limb lengthening and a decrease in hip offset. When symptoms are caused by an error in length and/or offset, revision arthroplasty may deserve consideration. PMID:26797005

  18. Uncemented custom femoral components in hip arthroplasty

    PubMed Central

    2010-01-01

    Background and purpose We have developed an individually designed, uncemented femoral component for achievement of improved strain distribution and fixation to the bone, to make uncemented stems more applicable in femurs of abnormal size and shape, and to improve the joint mechanics. Here we describe the design of the implant and present the results of a prospective clinical study with at least 7 years of follow-up. Patients and methods The prostheses are produced by CAD-CAM technique. The design of the stem is based on CT information, and the neck design is based on the surgeon's planning of the center of rotation, femoral head offset, and leg length correction. The first-generation stem produced before 2001 had a proximal HA coating and a sand-blasted distal part that was down-scaled to avoid contact with compact bone. The second-generation stem had a porous coating beneath the HA layer and the distal part of the stem was polished. The implant was used in 762 hips (614 patients) from 1995 until 2009. 191 of these hips were followed for 7 years and 83 others were followed for 10 years, and these hips are included in the present study. Mean age at surgery was 48 (20–65) years. Congenital dysplasia of the hip was the reason for osteoarthritis in 46% and 57% of the hips in respective groups. Merle d'Aubigné score was recorded in 152 and 75 hips in the two groups. Prostheses followed for 10 years, and almost all in the 7-year group, were first-generation stems. Results The 7- and 10-year cumulative revision rates were 1.1% and 2.4%, respectively, with stem revision for any reason as endpoint. The clinical results were similar at 7 and 10 years, with Merle d'Aubigné scores of 17. Intraoperative trochanteric fissures occurred in 2 of the 191 operations (1.0%); both healed after wiring. In hips followed for 7 years, 2 periprosthetic fractures occurred; exchange of the stem was necessary in both. One additional fracture occurred between 7 and 10 years, and it was treated successfully with osteosynthesis. The rate of dislocation was 1.6% and 2.4%, respectively. There was no radiographic loosening at follow-up. Interpretation Use of a custom femoral stem gives a reliable fixation and promising medium-term clinical results in femurs of normal and abnormal shape and dimension. The individual design, which enables optimized joint mechanics, gives a low risk of mechanical complications. PMID:20809741

  19. Formed HIP Can Processing

    SciTech Connect

    Clarke, Kester Diederik

    2015-07-27

    The intent of this report is to document a procedure used at LANL for HIP bonding aluminum cladding to U-10Mo fuel foils using a formed HIP can for the Domestic Reactor Conversion program in the NNSA Office of Material, Management and Minimization, and provide some details that may not have been published elsewhere. The HIP process is based on the procedures that have been used to develop the formed HIP can process, including the baseline process developed at Idaho National Laboratory (INL). The HIP bonding cladding process development is summarized in the listed references. Further iterations with Babcock & Wilcox (B&W) to refine the process to meet production and facility requirements is expected.

  20. Porous tantalum in hip and knee reconstructive surgery.

    PubMed

    Patil, Nilesh; Lee, Kevin; Goodman, Stuart B

    2009-04-01

    Conventional porous-coated joint prostheses used in hip and knee reconstruction have demonstrated good clinical results, however, these implants possess some inherent shortcomings such as low volumetric porosity, suboptimal frictional characteristics, and higher modulus of elasticity relative to that of bone. Porous tantalum, a novel porous biomaterial was developed to address these limitations. Extensive laboratory studies have revealed that porous tantalum has physical, mechanical and tissue in growth properties that makes it a potentially improved biomaterial particularly in complex joint reconstructions. Porous tantalum is a highly porous biomaterial with good biocompatibility, excellent corrosion resistance, and high coefficient of friction. The short term clinical results of porous tantalum in primary hip, revision hip, and knee reconstructive surgery are encouraging but further studies will be needed to determine whether the theoretical advantages of porous tantalum can provide long term biological fixation and stability. This review presents the biomaterial properties and clinical results of porous tantalum devices in hip and knee reconstructive surgeries. PMID:18837451

  1. Current expert views on metal-on-metal hip resurfacing arthroplasty. Consensus of the 6th advanced Hip resurfacing course, Ghent, Belgium, May 2014.

    PubMed

    Van Der Straeten, Catherine; De Smet, Koen A

    2016-02-01

    This paper reports the consensus of an international faculty of expert metal-on-metal (MoM) hip resurfacing surgeons, with a combined experience of over 40,000 cases, on the current status of hip resurfacing arthroplasty. Indications, design and metallurgy issues, release of metal ions and adverse soft tissue reactions to particles, management of problematic cases and revisions, as well as required experience and training are covered. The overall consensus is that MoM hip resurfacing should not be banned and should be viewed separately from MoM total hip arthroplasty (THA) with a large diameter head because of the different design and wear behaviour related to the taper/trunnion connection. The use of hip resurfacing has decreased worldwide but specialist centres continue to advocate hip resurfacing in young and active male patients. Regarding age the general recommendation is to avoid hip resurfacing in men older than 65 and in women older than 55, depending on the patient activity and bone quality. Female gender is considered a relative contraindication. Most surgeons would not implant a MoM hip in women who would still like a child. Regardless of gender, there is a consensus not to perform hip resurfacing in case of a femoral head size smaller than 46 mm and in patients with renal insufficiency or with a known metal allergy. Regarding follow-up of hip resurfacing and detection of adverse local tissue reactions, metal ion measurements, MRI and ultrasound are advocated depending on the local expertise. The consensus is that hip resurfacing should be limited to high volume hip surgeons, who are experienced in hip resurfacing or trained to perform hip resurfacing in a specialist centre. PMID:26449333

  2. Hip Offset in Total Hip Arthroplasty: Quantitative Measurement with Navigation

    PubMed Central

    Dastane, Manish; Tarwala, Rupesh; Wan, Zhinian

    2010-01-01

    Background Offset in THA correlates to abductor muscle function, wear, and impingement. Femoral offset after THA is not independent of the cup center of rotation (COR) so hip offset, a combination of femoral offset and change in hip COR, becomes the important measurement. Questions/purposes We therefore asked whether hip offset in arthritic hips would correlate with cup COR; whether offset could always be balanced within 6mm of contralateral normal hips; and whether hip length could also be kept within 6mm. Methods We compared hip offset of arthritic and contralateral normal hips on radiographs in 82 patients (82 hips) who had THA. We used computer navigation in all patients with the aim of reconstructing the hip offset and to compare hip offset change to the quantitative change of the hip COR. Results The preoperative radiographic change to equalize the offset ranged from ?12 to +21mm (mean, 1.5); postoperatively the change was 1.4 6.4mm and was within 6mm in 78 of 82 hips. As COR displaced superiorly from 3 to 6+ mm the offset had to be substantially increased. Only with COR 03mm superior and 05mm medial was offset always within 5mm. Conclusions Hip offset reconstruction was directly related to the position of the hip COR, and navigation allowed quantitative control of offset and hip length. PMID:20844997

  3. The CADCAM contribution to customized orthopaedic implants.

    PubMed

    Crawford, H V; Unwin, P S; Walker, P S

    1992-01-01

    CADCAM (computer aided design/manufacture) production methods are often associated with mass production; working in the medical field at the Department of Biomedical Engineering, the requirement is for one-off, individualized implants. Using a knowledge-based system, implant designs are produced from X-ray data. Assembly from modular components has greatly reduced the production time of implants for bone tumour cases. CADCAM techniques are also used in the production of custom-made hip replacements using digitized data gathered from radiographs. Femoral canal shape is calculated and the optimal implant designed and manufactured from titanium alloy on the Department's CNC (computer numerically controlled) machines. PMID:1418193

  4. Cochlear Implants.

    ERIC Educational Resources Information Center

    Clark, Catherine; Scott, Larry

    This brochure explains what a cochlear implant is, lists the types of individuals with deafness who may be helped by a cochlear implant, describes the process of evaluating people for cochlear implants, discusses the surgical process for implanting the aid, traces the path of sound through the cochlear implant to the brain, notes the costs of…

  5. Numerical optimization of composite hip endoprostheses under different loading conditions

    NASA Technical Reports Server (NTRS)

    Blake, T. A.; Davy, D. T.; Saravanos, D. A.; Hopkins, D. A.

    1992-01-01

    The optimization of composite hip implants was investigated. Emphasis was placed on the effect of shape and material tailoring of the implant to improve the implant-bone interaction. A variety of loading conditions were investigated to better understand the relationship between loading and optimization outcome. Comparisons of the initial and optimal models with more complex 3D finite element models were performed. The results indicate that design improvements made using this method result in similar improvements in the 3D models. Although the optimization outcomes were significantly affected by the choice of loading conditions, certain trends were observed that were independent of the applied loading.

  6. Adverse sequelae following revision of a total hip replacement for a fractured ceramic component: case report.

    PubMed

    Lee, Ling Hong; Langton, David; Green, Stephen

    2015-01-01

    Revision total hip replacement following a fractured ceramic bearing component presents a challenge in the choice of the new bearing implant. A femoral head made of equal or harder material should be implanted to prevent catastrophic wear. Despite this, patients and surgeons must be wary of potential complications. PMID:27163083

  7. Adverse sequelae following revision of a total hip replacement for a fractured ceramic component: case report

    PubMed Central

    Lee, Ling Hong; Langton, David; Green, Stephen

    2015-01-01

    Revision total hip replacement following a fractured ceramic bearing component presents a challenge in the choice of the new bearing implant. A femoral head made of equal or harder material should be implanted to prevent catastrophic wear. Despite this, patients and surgeons must be wary of potential complications.

  8. Medical implants and methods of making medical implants

    DOEpatents

    Shaw, Wendy J; Yonker, Clement R; Fulton, John L; Tarasevich, Barbara J; McClain, James B; Taylor, Doug

    2014-09-16

    A medical implant device having a substrate with an oxidized surface and a silane derivative coating covalently bonded to the oxidized surface. A bioactive agent is covalently bonded to the silane derivative coating. An implantable stent device including a stent core having an oxidized surface with a layer of silane derivative covalently bonded thereto. A spacer layer comprising polyethylene glycol (PEG) is covalently bonded to the layer of silane derivative and a protein is covalently bonded to the PEG. A method of making a medical implant device including providing a substrate having a surface, oxidizing the surface and reacting with derivitized silane to form a silane coating covalently bonded to the surface. A bioactive agent is then covalently bonded to the silane coating. In particular instances, an additional coating of bio-absorbable polymer and/or pharmaceutical agent is deposited over the bioactive agent.

  9. Cochlear Implants

    MedlinePlus

    ... Arts A cochlear implant is a small, complex electronic device that can help to provide a sense ... that can answer questions and provide printed or electronic information on cochlear implants: Cochlear implants Assistive technology ...

  10. NEUTRONIC REACTOR SHIELD AND SPACER CONSTRUCTION

    DOEpatents

    Wigner, E.P.; Ohlinger, L.A.

    1958-11-18

    Reactors of the heterogeneous, graphite moderated, fluid cooled type and shielding and spacing plugs for the coolant channels thereof are reported. In this design, the coolant passages extend horizontally through the moderator structure, accommodating the fuel elements in abutting end-to-end relationship, and have access openings through the outer shield at one face of the reactor to facilitate loading of the fuel elements. In the outer ends of the channels which extend through the shields are provided spacers and shielding plugs designed to offer minimal reslstance to coolant fluid flow while preventing emanation of harmful radiation through the access openings when closed between loadings.

  11. The Effect of Dislocation Type (Crowe Types I-IV) on Pelvic Development in Developmental Dysplasia of the Hip: A Radiologic Study of Anatomy.

    PubMed

    Bilgen, Ömer Faruk; Salar, Necmettin; Bilgen, Muhammet Sadık; Mutlu, Müren; Kara, Gökhan Kürşat; Gürsel, Enis

    2015-05-01

    Classification of hip pathology in developmental dysplasia of the hip (DDH) helps in appropriate placement of implants during total hip arthroplasty. We examined preoperative unilateral and bilateral pelvic radiographs of 57 patients (114 hips) undergoing total hip arthroplasty because of DDH. Both sides of the pelvis were visually separated into 3 areas for comparison. When area ratios of hips with Crowe types II, III, and IV DDH were compared with ratios for healthy hips, values in hips with DDH were significantly low for the iliac wings, significantly high for the acetabular regions, and significantly low for the ischial area. Using a line crossing the healthy hip's teardrop and parallel to a line joining the distal sacroiliac joints is useful for calculating limb-length discrepancy. PMID:25499171

  12. Hip endoprosthesis for in vivo measurement of joint force and temperature.

    PubMed

    Graichen, F; Bergmann, G; Rohlmann, A

    1999-10-01

    Friction between the prosthetic head and acetabular cup increases the temperature in hip implants during activities like walking. A hip endoprosthesis was instrumented with sensors to measure the joint contact forces and the temperature distribution along the entire length of the titanium implant. Sensors and two inductively powered telemetry units are placed inside the hip implant and hermetically sealed against body fluids. Each telemetry unit contains an integrated 8-channel telemetry chip and a radio frequency transmitter. Force, temperature and power supply data are transmitted at different frequencies by two antennas to an external twin receiver. The inductive power supply is controlled by a personal computer. Force and temperature are monitored in real time and all data are stored on a video tape together with the patient's images. This paper describes the design and accuracy of the instrumented implant and the principal function of the external system components. PMID:10476850

  13. Hip fusion as hip salvage procedure in cerebral palsy.

    PubMed

    Fucs, Patricia M De Moraes Barros; Yamada, Helder H

    2014-01-01

    The treatment of the spastic hip in Cerebral Palsy (CP) remains a challenge especially in cases of advance changes. Many options are available and the key for a good outcome is to find the best surgical procedure to an individualized patient. The hip fusion is one of the surgical options. The authors presented a group of spastic CP with painful chronic hip subluxation and dislocation treated with hip fusion with a mean follow-up period of 14.5 years. Surgical technique, post-operative management and outcomes were shown, also with the observations done regarding the evolution of the contralateral hip after the hip fusion. They concluded that the hip arthrodesis is an option for patients with spastic CP with painful subluxation or dislocated hips with the goal of pain relief maintain or improve functional status, and facilitating the care. The best candidate is a young ambulatory patient with normal contralateral hip and normal spinal alignment. PMID:25207734

  14. 21 CFR 888.3320 - Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... cemented acetabular component, prosthesis. 888.3320 Section 888.3320 Food and Drugs FOOD AND DRUG..., prosthesis. (a) Identification. A hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis is a two-part device intended to be implanted to replace a hip joint. The...

  15. 21 CFR 888.3330 - Hip joint metal/metal semi-constrained, with an uncemented acetabular component, prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... uncemented acetabular component, prosthesis. 888.3330 Section 888.3330 Food and Drugs FOOD AND DRUG..., prosthesis. (a) Identification. A hip joint metal/metal semi-constrained, with an uncemented acetabular component, prosthesis is a two-part device intended to be implanted to replace a hip joint. The...

  16. 21 CFR 888.3353 - Hip joint metal/ceramic/polymer semi-constrained cemented or nonporous uncemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... cemented or nonporous uncemented prosthesis. 888.3353 Section 888.3353 Food and Drugs FOOD AND DRUG... prosthesis. (a) Identification. A hip joint metal/ceramic/polymer semi-constrained cemented or nonporous uncemented prosthesis is a device intended to be implanted to replace a hip joint. This device...

  17. 21 CFR 888.3330 - Hip joint metal/metal semi-constrained, with an uncemented acetabular component, prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... uncemented acetabular component, prosthesis. 888.3330 Section 888.3330 Food and Drugs FOOD AND DRUG..., prosthesis. (a) Identification. A hip joint metal/metal semi-constrained, with an uncemented acetabular component, prosthesis is a two-part device intended to be implanted to replace a hip joint. The...

  18. 21 CFR 888.3320 - Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... cemented acetabular component, prosthesis. 888.3320 Section 888.3320 Food and Drugs FOOD AND DRUG..., prosthesis. (a) Identification. A hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis is a two-part device intended to be implanted to replace a hip joint. The...

  19. 21 CFR 888.3320 - Hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... cemented acetabular component, prosthesis. 888.3320 Section 888.3320 Food and Drugs FOOD AND DRUG..., prosthesis. (a) Identification. A hip joint metal/metal semi-constrained, with a cemented acetabular component, prosthesis is a two-part device intended to be implanted to replace a hip joint. The...

  20. 21 CFR 888.3330 - Hip joint metal/metal semi-constrained, with an uncemented acetabular component, prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... uncemented acetabular component, prosthesis. 888.3330 Section 888.3330 Food and Drugs FOOD AND DRUG..., prosthesis. (a) Identification. A hip joint metal/metal semi-constrained, with an uncemented acetabular component, prosthesis is a two-part device intended to be implanted to replace a hip joint. The...

  1. 21 CFR 888.3353 - Hip joint metal/ceramic/polymer semi-constrained cemented or nonporous uncemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... cemented or nonporous uncemented prosthesis. 888.3353 Section 888.3353 Food and Drugs FOOD AND DRUG... prosthesis. (a) Identification. A hip joint metal/ceramic/polymer semi-constrained cemented or nonporous uncemented prosthesis is a device intended to be implanted to replace a hip joint. This device...

  2. 21 CFR 888.3353 - Hip joint metal/ceramic/polymer semi-constrained cemented or nonporous uncemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... cemented or nonporous uncemented prosthesis. 888.3353 Section 888.3353 Food and Drugs FOOD AND DRUG... prosthesis. (a) Identification. A hip joint metal/ceramic/polymer semi-constrained cemented or nonporous uncemented prosthesis is a device intended to be implanted to replace a hip joint. This device...

  3. Treatment of hip dysplasia.

    PubMed

    Anderson, A

    2011-04-01

    Hip dysplasia is a common orthopaedic developmental disorder of dogs. This paper reviews the treatment options available for management of the condition in the skeletally immature and adult dog. PMID:21906059

  4. Minimally invasive hip replacement

    MedlinePlus

    ... Smits SA, Swinford RR, Bahamonde RE. A randomized, prospective study of 3 minimally invasive surgical approaches in total hip arthroplasty: comprehensive gait analysis. J Arthroplasty . 2008;23:68-73. PMID: 18722305 ...

  5. Hip flexor strain - aftercare

    MedlinePlus

    ... 2015:chap 87. Reider BC, Daview GJ, Provencher MT. Muscle strains about the hip and thigh. In: Reider BC, Daview GJ, Provencher MT. Orthopaedic Rehabilitation of the Athlete . Philadelphia, PA: Elsevier ...

  6. Hip joint replacement

    MedlinePlus

    ... A socket, which is usually made of strong metal. A liner, which fits inside the socket. It is usually plastic, but some surgeons are now trying other materials, like ceramic. The liner allows the hip to ...

  7. HIP osteoarthritis and work.

    PubMed

    Harris, E Clare; Coggon, David

    2015-06-01

    Epidemiological evidence points strongly to a hazard of hip osteoarthritis from heavy manual work. Harmful exposures may be reduced by the elimination or redesign of processes and the use of mechanical aids. Reducing obesity might help to protect workers whose need to perform heavy lifting cannot be eliminated. Particularly high relative risks have been reported in farmers, and hip osteoarthritis is a prescribed occupational disease in the UK for long-term employees in agriculture. Even where it is not attributable to employment, hip osteoarthritis impacts importantly on the capacity to work. Factors that may influence work participation include the severity of disease, the physical demands of the job, age and the size of the employer. Published research does not provide a strong guide to the timing of return to work following hip arthroplasty for osteoarthritis, and it is unclear whether patients should avoid heavy manual tasks in their future employment. PMID:26612242

  8. HIP OSTEOARTHRITIS AND WORK

    PubMed Central

    Harris, E Clare; Coggon, David

    2016-01-01

    Epidemiological evidence points strongly to a hazard of hip osteoarthritis from heavy manual work. Harmful exposures may be reduced by elimination or redesign of processes and use of mechanical aids. Reducing obesity might help to protect workers whose need to perform heavy lifting cannot be eliminated. Particularly high relative risks have been reported in farmers, and hip osteoarthritis is a prescribed occupational disease in the UK for long-term employees in agriculture. Even where it is not attributable to employment, hip osteoarthritis impacts importantly on capacity to work. Factors that may influence work participation include the severity of disease, the physical demands of the job, age, and the size of the employer. Published research does not provide a strong guide to the timing of return to work following hip arthroplasty for osteoarthritis, and it is unclear whether patients should avoid heavy manual tasks in their future employment. PMID:26612242

  9. Arthroscopic hip labral repair.

    PubMed

    Philippon, Marc J; Faucet, Scott C; Briggs, Karen K

    2013-05-01

    Labral tears in the hip may cause painful clicking or locking of the hip, reduced range of motion, and disruption to sports and daily activities. The acetabular labrum aids stabilization of the hip joint, particularly during hip motion. The fibrocartilaginous structure extends the acetabular rim and provides a suction seal around the femoroacetabular interface. Treatment options for labral tears include debridement, repair, and reconstruction. Repair of the labrum has been shown to have better results than debridement. Labral refixation is achieved with sutures anchored into the acetabular rim. The acetabular rim is trimmed either to correct pincer impingement or to provide a bleeding bed to improve healing. Labral repair has shown excellent short-term to midterm outcomes and allows patients to return to activities and sports. Arthroscopic rim trimming and labral refixation comprise an effective treatment for labral tears with an underlying diagnosis of femoroacetabular impingement and are supported by the peer-reviewed literature. PMID:23875153

  10. Revision total hip arthroplasty: hospital cost and reimbursement analysis.

    PubMed

    Crowe, John F; Sculco, Thomas P; Kahn, Barbara

    2003-08-01

    Revision total hip arthroplasty is a complex surgical procedure that frequently requires high levels of hospital resources. The purpose of the current study was to report the actual costs and reimbursement to the hospital for a stratified group of patients having revision total hip arthroplasty based on a severity index. The clinical and financial records of 49 patients (51 hips) stratified by complexity of revision were reviewed. Clinical variable included age, length of stay, operating time, estimated blood loss, number of transfusions, implant type, metallic augmentation, use of bone graft, and time spent in the postanesthesia care unit. Financial review included the actual fixed and variable costs associated with each procedure. Hospital costs associated with revision total hip arthroplasty were significantly greater in the most complex revisions and in older patients. The use of bone grafting techniques on the femur resulted in significantly greater costs. The average loss to the hospital was $5402 US dollars per procedure with a range of $5657 (US dollars) profit to $28,780 (US dollars) loss. Procedures in patients younger than 65 years has an average loss of $1133 US dollars. All procedures in patients who were 65 years or older resulted in a loss to the hospital, with the average loss being $8617 US dollars. Despite improvements in length of stay, use of clinical pathways, and negotiated discounts on implants, the hospital loss on each hip revision procedure averaged $5402 US dollars. PMID:12897608

  11. Fracture of the Modular Neck in Total Hip Arthroplasty.

    PubMed

    Hernandez, A; Gargallo-Margarit, A; Barro, V; Gallardo-Calero, I; Sallent, A

    2015-01-01

    Modularity of the components in total hip arthroplasty has had an increase in popularity in the last decades. We present the case of a 53-year-old man with a history of avascular necrosis of the femoral head due to a hypophyseal adenoma. A total hip modular arthroplasty was implanted. Three and a half years after the surgery the patient attended the emergency room due to acute left hip pain with no prior traumatism. Radiological examination confirmed a fracture of the modular neck. A revision surgery was performed finding an important pseudotumoral well-organized periprosthetic tissue reaction. Through an extended trochanteric osteotomy the femoral component was removed, and a straight-stem revision prosthesis implanted. There are several potential advantages when using modularity in total hip arthroplasty that surgeons may benefit from, but complications have arisen and must be addressed. Various circumstances such as large femoral head with a long varus neck, corrosion, patient's BMI, and activity level may participate in creating the necessary environment for fatigue failure of the implant. PMID:26266069

  12. Fracture of the Modular Neck in Total Hip Arthroplasty

    PubMed Central

    Hernandez, A.; Gargallo-Margarit, A.; Barro, V.; Gallardo-Calero, I.; Sallent, A.

    2015-01-01

    Modularity of the components in total hip arthroplasty has had an increase in popularity in the last decades. We present the case of a 53-year-old man with a history of avascular necrosis of the femoral head due to a hypophyseal adenoma. A total hip modular arthroplasty was implanted. Three and a half years after the surgery the patient attended the emergency room due to acute left hip pain with no prior traumatism. Radiological examination confirmed a fracture of the modular neck. A revision surgery was performed finding an important pseudotumoral well-organized periprosthetic tissue reaction. Through an extended trochanteric osteotomy the femoral component was removed, and a straight-stem revision prosthesis implanted. There are several potential advantages when using modularity in total hip arthroplasty that surgeons may benefit from, but complications have arisen and must be addressed. Various circumstances such as large femoral head with a long varus neck, corrosion, patient's BMI, and activity level may participate in creating the necessary environment for fatigue failure of the implant. PMID:26266069

  13. Fixation using alternative implants for the treatment of hip fractures (FAITH): design and rationale for a multi-centre randomized trial comparing sliding hip screws and cancellous screws on revision surgery rates and quality of life in the treatment of femoral neck fractures

    PubMed Central

    2014-01-01

    Background Hip fractures are a common type of fragility fracture that afflict 293,000 Americans (over 5,000 per week) and 35,000 Canadians (over 670 per week) annually. Despite the large population impact the optimal fixation technique for low energy femoral neck fractures remains controversial. The primary objective of the FAITH study is to assess the impact of cancellous screw fixation versus sliding hip screws on rates of revision surgery at 24 months in individuals with femoral neck fractures. The secondary objective is to determine the impact on health-related quality of life, functional outcomes, health state utilities, fracture healing, mortality and fracture-related adverse events. Methods/Design FAITH is a multi-centre, multi-national randomized controlled trial utilizing minimization to determine patient allocation. Surgeons in North America, Europe, Australia, and Asia will recruit a total of at least 1,000 patients with low-energy femoral neck fractures. Using central randomization, patients will be allocated to receive surgical treatment with cancellous screws or a sliding hip screw. Patient outcomes will be assessed at one week (baseline), 10 weeks, 6, 12, 18, and 24 months post initial fixation. We will independently adjudicate revision surgery and complications within 24 months of the initial fixation. Outcome analysis will be performed using a Cox proportional hazards model and likelihood ratio test. Discussion This study represents major international efforts to definitively resolve the treatment of low-energy femoral neck fractures. This trial will not only change current Orthopaedic practice, but will also set a benchmark for the conduct of future Orthopaedic trials. Trial registration The FAITH trial is registered at ClinicalTrials.gov (Identifier NCT00761813). PMID:24965132

  14. HIP ARTHROSCOPY IN ATHLETES

    PubMed Central

    Polesello, Giancarlo Cavalli; Keiske Ono, Nelson; Bellan, Davi Gabriel; Honda, Emerson Kiyoshi; Guimarães, Rodrigo Pereira; Junior, Walter Riccioli; Do Val Sella, Guilherme

    2015-01-01

    To confirm the therapeutic importance of hip arthroplasty in athletes whose pain precludes sportive function of the hip joint, being able to minimize it to the extent of helping on the return of sports practice at satisfactory levels. Methods: 49 athlete patients (51 hips) submitted to hip arthroscopy complaining of pain and inability to practice sports were assessed. Follow-up time ranged from 12 to 74 months (mean: 39.0 months). Preoperatively, pain site, severity according to Facial Expression Scale (FES) and the degree of disability using the modified Harris Hip Score (HHS) were assessed. Different diagnoses were provided, which led to the indication of arthroscopy, such as femoralacetabular impact, acetabular lip injury not secondary to femoral-acetabular impact, etc. Postoperatively, the patients were assessed by using the same methods as used at baseline and by the subjective analysis of return to sports activities. Results: Based on pre-and postoperative HHS and FES, the statistical analysis showed significance between values. We found some improvement in all cases and return to sports activities at a satisfactory level in most of the cases. Conclusion: As a result of our study, we confirm that arthroscopy in athletes with local hip injuries is an effective technique, able to promote the return to sports practice in most of the cases, without pain, and with an effective joint function, provided well indicated. PMID:26998449

  15. Ilizarov hip reconstruction without external fixation: a new technique

    PubMed Central

    Lenze, U.; Hasler, C. C.

    2010-01-01

    Purpose The Ilizarov hip reconstruction is a well accepted but complication-prone operative salvage procedure in chronically dislocated hips, not least due to the long-term application of external fixation. Although the advantages of fully implantable devices are well known in limb lengthening and are described consistently, until now, external fixation has been used exclusively to perform the Ilizarov hip reconstruction procedure. We present a new technique of Ilizarov hip reconstruction with purely internal implants. Methods A 14-year-old girl with a history of spina bifida presented with a 4-cm-short right leg, a Trendelenburg gait and a complex neurological disease expression. Because of refusal of external fixation by the patient and significantly lower complication rates, an Ilizarov hip reconstruction without external fixation was performed. A locking compression plate was applied to fix the proximal femoral valgus-extension osteotomy and a motorised intramedullary distraction nail was used for the distal, lengtheningvarisation osteotomy. Results A healing index of 33days/cm and full weight bearing after 6months were noted. At the 1year follow-up, the patient showed an improvement of the Trendelenburg gait, as well as successful leg equalisation. Satisfaction to a high degree was additionally noted by factors such as reduced pain, the ability to wear workaday clothes and cosmetically appealing scars. No complications were recorded. Conclusion The exclusive use of internal implants for Ilizarov hip reconstruction is a feasible and patient-friendly alternative to traditional methods. Their use, however, may be restricted by geometric preconditions. PMID:21629378

  16. Dental Implants

    MedlinePlus

    ... helpful facts so you can make an informed decision as to whether dental implants are right for your situation. Dental Implants and Roots The key benefit of dental implants over other tooth replacement systems is that an implant connects directly to the ...

  17. CIRCUMFERENTIAL PROXIMAL FEMORAL ALLOGRAFTS IN TOTAL HIP ARTHROPLASTY REVISION SURGERY

    PubMed Central

    Roos, Bruno Dutra; Roos, Milton Valdomiro; Júnior, Antero Camisa; Lampert, Henrique Bonotto; da Silva, Matheus Luis

    2015-01-01

    Objective: To evaluate the clinical and radiographic results from patients who underwent femoral reconstruction secondary to loosening of total hip arthroplasty, using circumferential proximal femoral allografts and cemented implants. Methods: A retrospective study was conducted on 32 patients (33 hips) who underwent femoral reconstruction secondary to loosening of total hip arthroplasty, using circumferential proximal femoral allografts and cemented implants. Among these patients, 28 (29 hips) fulfilled all the requirements for this study. The mean follow-up was five years and two months. The clinical evaluation was done in accordance with the Harris Hip Score. Radiographically, the patients were assessed regarding reabsorption and consolidation of the allograft, migration of the greater trochanter, stability of the femoral component and heterotypic calcification. Results: The average preoperative Harris Hip Score was 32 points. At the last postoperative follow-up, the average score was 82 points. Allograft resorption of some degree was seen in nine hips (31%). Regarding consolidation, 24 cases (82.8%) showed full consolidation, three (10.3%) showed partial consolidation and two (6.9%) showed pseudarthrosis. All femoral components were stable. According to the criteria established, 27 cases (93.1%) were considered to be successful reconstructions after a mean follow-up of five years and two months. Conclusion: From the results obtained, it was concluded that use of circumferential proximal femoral allografts in selected cases of femoral reconstruction secondary to loosening of arthroplasty presented a high survival rate from the reconstruction over an average follow-up of five years and two months.

  18. The Result of Revision Total Hip Arthroplasty in Patients with Metallosis Following a Catastrophic Failure of a Polyethylene Liner

    PubMed Central

    Kwak, Hong Suk; Lee, Young-Kyun; Koo, Kyung-Hoi; Yoon, Kang Sup; Kim, Hee Joong

    2015-01-01

    Background Wear cannot be completely prevented after total hip arthroplasty. If severe polyethylene (PE) liner wear develops, the so-called catastrophic failure occurs and metallosis develops. We postulated that longevity of the new implant may be affected after revision surgery for metallosis following a catastrophic failure of a PE liner due to the substantial amount of PE wear particles and infiltration of the metal particles in this catastrophic condition. Methods Twenty-three hips of 23 patients were identified because they showed metallosis during revision total hip arthroplasties performed in Seoul National University Hospital between January 1996 and August 2004. They were followed for at least 6.5 years after the index revision total hip arthroplasty. The clinical and radiological results of revision total hip arthroplasties in these patients were evaluated. Results The median Harris hip score increased from 60 points before revision total hip arthroplasties to 90 points at the final follow-up. Osteolysis was detected at an average of 9.3 years after revision total hip arthroplasties in 13 hips and acetabular cup loosening at average 9.8 years after revision total hip arthroplasties in 9 hips. With radiographic evidence of osteolysis and loosening as the end points, the 15-year survival rates were 28.2% and 56.0%, respectively. Conclusions The survival rate of revision total hip arthroplasty in patients with metallosis following a catastrophic failure of a PE liner was low. PMID:25729518

  19. SU-E-J-230: Effect of Metal Hip Prosthesis On the Accuracy of Electromagnetic Localization and Tracking

    SciTech Connect

    Butler, W; Merrick, G; Kurko, B; Bittner, N

    2014-06-01

    Purpose: To quantify the effect of metal hip prosthesis on the ability to track and localize electromagnetic transponders. Methods: Three Calypso transponders were implanted into two prostate phantoms. The geometric center of the transponders were identified on computed tomography and set as the isocenter. With the phantom stationary on the treatment table and the tracking array 14-cm above the isocenter, data was acquired by the Calypso system at 10 Hz to establish the uncertainty in measurements. Transponder positional data was acquired with unilateral hip prostheses of different metallic compositions and then with bilateral hips placed at variable separation from the phantom. Results: Regardless of hip prosthesis composition, the average vector displacement in the presence of a unilateral prosthesis was < 0.5 mm. The greatest contribution to overall vector displacement occurred in the lateral dimension. With bilateral hip prosthesis, the average vector displacement was 0.3 mm. The displacement in the lateral dimension was markedly reduced compared with a unilateral hip, suggesting that there was a countervailing effect with bilateral hip prosthesis. The greatest average vector displacement was 0.6 mm and occurred when bilateral hip prostheses were placed within 4 cm of the detector array. Conclusion: Unilateral and bilateral hip prostheses did not have any meaningful effect on the ability to accurately track electromagnetic transponders implanted in a prostate phantom. At clinically realistic distances between the hip and detection array, the average tracking error is negligible.

  20. Complications After Hip Nailing for Fractures.

    PubMed

    Mavrogenis, Andreas F; Panagopoulos, Georgios N; Megaloikonomos, Panayiotis D; Igoumenou, Vasilios G; Galanopoulos, Ioannis; Vottis, Christos T; Karabinas, Panayiotis; Koulouvaris, Panayiotis; Kontogeorgakos, Vasilios A; Vlamis, John; Papagelopoulos, Panayiotis J

    2016-01-01

    Pertrochanteric fractures in elderly patients represent a major health issue. The available surgical options are fixation with extramedullary devices, intramedullary nailing, and arthroplasty. Intramedullary nailing for hip fractures has become more popular in recent years. Advantages of intramedullary nailing for hip fracture fixation include a more efficient load transfer due to the proximity of the implant to the medial calcar, less implant strain and shorter lever arm because of its closer positioning to the mechanical axis of the femur, significantly less soft tissue disruption and periosteal stripping of the femoral cortex, shorter operative time and hospital stay, fewer blood transfusions, better postoperative walking ability, and lower rates of leg-length discrepancy. Compromise of the posteromedial cortex and/or the lateral cortex, a subtrochanteric extension of the fracture, and a reversed obliquity fracture pattern represent signs of fracture instability, warranting the use of intramedullary nailing. However, the use of intramedullary nailing, with its unique set of clinical implications, has introduced a new set of complications. The reported complications include malalignment, cutout, infection, false drilling, wrong lag screw length and drill bit breakage during the interlocking procedure, external or internal malrotation (≥20°) of the femoral diaphysis, elongation of the femur (2 cm), impaired bone healing, periprosthetic fracture distal to the tip of the nail, fracture collapse, implant failure, lag screw intrapelvic migration, neurovascular injury, secondary varus deviation, complications after implant removal, trochanteric pain, and refracture. Many of these complications are related to technical mistakes. This article reviews intramedullary nailing for the treatment of pertrochanteric femoral fractures, with an emphasis on complications. [Orthopedics. 2016; 39(1):e108-e116.]. PMID:26726984

  1. Geriatric hip fracture clinical pathway: the Hong Kong experience

    PubMed Central

    Leung, F.; Siu, D.; Wong, G.; Luk, K. D. K.

    2010-01-01

    Geriatric hip fracture is one of the commonest fractures in orthopaedic trauma. There is a trend of further increase in its incidence in the coming decades. Besides the development of techniques and implants to overcome the difficulties in fixation of osteoporosis bone, the general management of the hip fracture is also very challenging in terms of the preparation of the generally poorer pre-morbid state and complicate social problems associated with this group of patients. In order to cope with the increasing demand, our hospital started a geriatric hip fracture clinical pathway in 2007. The aim of this pathway is to provide better care for this group of patients through multidisciplinary approach. From year 2007 to 2009, we had managed 964 hip fracture patients. After the implementation of the pathway, the pre-operative and the total length of stay in acute hospital were shortened by over 5 days. Other clinical outcomes including surgical site infection, 30 days mortality and also incidence of pressure sore improved when compared to the data before the pathway. The rate of surgical site infection was 0.98%, and the 30 days mortality was 1.67% in 2009. The active participation of physiotherapists, occupational therapists as well as medical social workers also helped to formulate the discharge plan as early as the patient is admitted. In conclusion, a well-planned and executed clinical pathway for hip fracture can improve the clinical outcomes of the geriatric hip fractures. PMID:19543764

  2. Bearing surfaces in hip replacement – Evolution and likely future

    PubMed Central

    Kumar, Narinder; Arora, Gen N.C.; Datta, Barun

    2014-01-01

    Total hip arthroplasty has evolved from the first total hip arthroplasty in 1938, through the revolutionization of hip arthroplasty by principles of low friction arthroplasty introduced by Sir John Charnley in 1960s to the present state of the art implants and techniques. The main concern regarding failure of total hip arthroplasty has been the biological response to particulate polyethylene debris generated by conventional metal on polyethylene bearing surfaces leading to osteolysis and aseptic loosening of the prosthesis. Therefore, recent research has been focussing on alternative bearing surfaces to reduce the particulate debris generated. These bearing surfaces include ceramic-polyethylene, metal–metal as well as ceramic–ceramic articulations and have demonstrated lesser friction rates as well as significantly lower wear rates as compared to widely used metal on polyethylene surfaces. Clinical experience until now has shown that metal on metal articulations have significant safety concerns whereas metal-on-highly crosslinked polyethylene, ceramic on ceramic and ceramic on highly crosslinked polyethylene articulations have shown encouraging results to hold promise for wider use in younger and more active patients. This review article discusses positives and drawbacks of various bearing surfaces in current clinical use in total hip arthroplasty as well as briefly explores the newer technologies on the horizon which may even further decrease wear and improve total hip arthroplasty survivorship. PMID:25382913

  3. Designing string-of-beads vaccines with optimal spacers.

    PubMed

    Schubert, Benjamin; Kohlbacher, Oliver

    2016-01-01

    String-of-beads polypeptides allow convenient delivery of epitope-based vaccines. The success of a polypeptide relies on efficient processing: constituent epitopes need to be recovered while avoiding neo-epitopes from epitope junctions. Spacers between epitopes are employed to ensure this, but spacer selection is non-trivial.We present a framework to determine optimally the length and sequence of a spacer through multi-objective optimization for human leukocyte antigen class I restricted polypeptides. The method yields string-of-bead vaccines with flexible spacer lengths that increase the predicted epitope recovery rate fivefold while reducing the immunogenicity from neo-epitopes by 44 % compared to designs without spacers. PMID:26813686

  4. Biomechanically induced tissue reactions after Al2O3-ceramic hip joint replacement. Experimental and early clinical results.

    PubMed

    Griss, P; Silber, R; Merkle, B; Haehner, K; Heimke, G; Krempien, B

    1976-07-01

    A biomechanical concept of interface maturation around cement-free implanted alumina-ceramic hip endoprostheses in sheep is explained. Provided there is rigid primary stability of the implant within the bone bed, hard tissue formation along the support areas of the implant is mainly dependent on implant shape and main local stress direction. Three subsequent phases of interface maturation can be distinguished, finally resulting in firm fixation of the implant by mechanical interlocking of supporting bone and ceramic. A new composite alumina-metal hip endoprosthesis for partial cement-free implantation (cup) is presented. The technique, postoperative care, and encouraging early results in 5 patients are demonstrated. A new ceramic femoral component for cement free implantation is proposed. PMID:947915

  5. [Spinal column: implants and revisions].

    PubMed

    Krieg, S M; Meyer, H S; Meyer, B

    2016-03-01

    Non-fusion spinal implants are designed to reduce the commonly occurring risks and complications of spinal fusion surgery, e.g. long duration of surgery, high blood loss, screw loosening and adjacent segment disease, by dynamic or movement preserving approaches. This principle could be shown for interspinous spacers, cervical and lumbar total disc replacement and dynamic stabilization; however, due to the continuing high rate of revision surgery, the indications for surgery require as much attention and evidence as comparative data on the surgical technique itself. PMID:26779646

  6. Artificial hip joints: The biomaterials challenge.

    PubMed

    Pezzotti, Giuseppe; Yamamoto, Kengo

    2014-03-01

    What is new and what comes next in artificial hip joints? These are the crucial questions we attempt to answer after accurately surveying the state of the art in the field of hip arthroplasty, especially related to non-metallic materials. Summarizing the present situation, one could safely state that the current generation of hard-on-soft and hard-on-hard hip bearings has become quite effective in exhibiting extremely low degrees of wear when compared to traditional implants made of cobalt-chromium alloys coupled with conventional polyethylene materials or to the primitive alumina materials used in the past. Moreover, at a stage of more than 10 years in the clinical follow-up of new generations of hard-on-hard bearings, and more than 10 years follow-up for highly cross-linked polyethylene materials, we should soon be expecting a new set of officially compiled statistics that show significant reductions in failures due to particle-mediated osteolysis as compared to past statistical compilations. However, further important issues (other than wear) remain unsolved, including structural reliability of advanced ceramic and polyethylene components. Severe challenges yet stand in optimizing the biomaterials choice for significantly extended lifetimes and reduced failure risks. Moreover, joint healing trends are expected to evolve more radically in the next few decades. PMID:23867294

  7. Ten different hip resurfacing systems: biomechanical analysis of design and material properties

    PubMed Central

    Kleinhans, Jennifer A.; Menge, Michael; Kretzer, Jan Philippe

    2008-01-01

    This study gives an overview of the main macro- and microstructural differences of ten commercially available total hip resurfacing implants. The heads and cups of resurfacing hip implants from ten different manufacturers were analysed. The components were measured in a coordinate measuring machine. The microstructure of the heads and cups was inspected by scanning electron microscopy. The mean radial clearance was 84.86 μm (range: 49.47–120.93 μm). The implants were classified into three groups (low, medium and high clearance). All implants showed a deviation of roundness of less than 10 μm. It was shown that all implants differ from each other and a final conclusion about the ideal design and material combination cannot be given based on biomechanical data. Widespread use of specific designs can only be recommended if clinical long-term follow-up studies are performed and analysed for each design. PMID:18600323

  8. Hip joint replacement - series (image)

    MedlinePlus

    ... hip socket. The socket is usually made of metal. A liner that fits inside the socket. It ... usually plastic, but some surgeons use ceramic and metal. The liner allows the hip to move smoothly. ...

  9. Dual mobility cups in total hip arthroplasty

    PubMed Central

    De Martino, Ivan; Triantafyllopoulos, Georgios Konstantinos; Sculco, Peter Keyes; Sculco, Thomas Peter

    2014-01-01

    Total hip arthroplasty (THA) is considered one of the most successful surgical procedures in orthopaedics. With the increase in the number of THAs performed in the world in the next decades, reducing or preventing medical and mechanical complications such as post-operative THA instability will be of paramount importance, particularly in an emerging health care environment based on quality control and patient outcome. Dual mobility acetabular component (also known as unconstrained tripolar implant) was introduced in France at the end of the 1970s as an alternative to standard sockets, to reduce the risk of THA dislocation in patients undergoing primary THA in France. Dual mobility cups have recently gained wider attention in the United States as an alternative option in the prevention and treatment of instability in both primary and revision THA and offer the benefit of increased stability without compromising clinical outcomes and implant longevity. In this article, we review the use of dual mobility cup in total hip arthroplasty in terms of its history, biomechanics, outcomes and complications based on more than 20 years of medical literature. PMID:25035820

  10. Modular noncemented total hip arthroplasty for congenital dislocation of the hip. Case report and design rationale.

    PubMed

    Gorski, J M

    1988-03-01

    The highest rate of failure and the greatest technical difficulty in total hip arthroplasty occurs with congenital dislocation of the hip (CDH). Predisposing factors are failure to secure special femoral components to fit an extremely narrow and straight medullary cavity with space for only a very thin mantle of cement. The acetabulum is usually atrophic, and bone grafts are commonly required to support a small-diameter cup. The young age of the average patient and high levels of activity contribute to cement failure. A new modular cementless prosthesis provides excellent immediate skeletal fixation and pain relief in CDH patients. Five modular components are screwed or press-fit into bone. The modular approach facilitates implantation, reduces inventory, and is adaptable to unforeseen problems. These advantages are ordinarily absent with standard or custom cemented components. Modular components may also permit easier revision. The prosthesis is made of titanium alloy for its superalloy strength, elastic modulus, and bioinertness. By omitting the cement mantle, press-fit is obtained with the largest possible implant. The large size minimizes stem breakage in these young, small bones. Excellent short-term results suggest that modular cementless implants are indicated in some patients with CDH. PMID:3342552

  11. New experience with alumina-on-alumina ceramic bearings for total hip arthroplasty.

    PubMed

    D'Antonio, James; Capello, William; Manley, Michael; Bierbaum, Benjamin

    2002-06-01

    A major challenge for total hip arthroplasty is to minimize wear and osteolysis in young, active patients. Alumina ceramic bearings have shown superior wear resistance and lubrication and do not carry the risk of ion release. In a prospective randomized study, 514 hips were implanted. All patients (average age, 53 years) received the same press-fit hydroxyapatite coated femoral stem; two thirds (345 hips) received alumina ceramic bearings, and one third (169 hips) received a cobalt-chrome-on-polyethylene bearing. At a mean follow-up of 35.2 months (range, 24-48 months), there was no significant difference in clinical performance between the patient cohorts. No ceramic fracture or alumina ceramic bearing failure occurred. This new experience involves the use of improved ceramic materials and new design considerations that eliminate the risks and complications of past experiences with ceramic implants and provides a safe bearing option for young patients. PMID:12066265

  12. [Hip resurfacing arthroplasty].

    PubMed

    Witzleb, W-C; Knecht, A; Beichler, T; Köhler, T; Günther, K-P

    2004-11-01

    In comparison to stemmed total hip replacements, hip resurfacing offers advantages especially in joint stability and amount of femoral bone resection. After the poor results achieved with this concept that were mainly caused by failure of the materials used, reintroduction of the metal-on-metal bearing initiated a renaissance. This bearing, the cementless cup, and the improved surgical technique led to better short- to medium-term results. Revision and complication rates are now comparable to conventional total hip replacements. The functional capacity of the method is higher. Because long-term results are not available, however, questions remain, for instance, the consequences of the higher metal ion serum concentrations or the impossibility of changing the inlay when femoral revision becomes necessary. PMID:15549248

  13. Hip impingement: beyond femoroacetabular

    PubMed Central

    Bardakos, Nikolaos V.

    2015-01-01

    In the last 20 years, femoroacetabular impingement has been at the forefront of clinical practice as a cause of hip pain in young adults. As arthroscopic techniques for the hip continue to evolve, the possible presence of a new group of conditions creating mechanical conflict in and around the hip joint (ischiofemoral, subspine and iliopsoas impingement) has recently been elucidated whilst interest in already known ‘impingement’ syndromes (pelvic-trochanteric and pectineofoveal impingement) is now revived. This article attempts to increase awareness of these relatively uncommon clinical entities by describing their pathomorphology, contact mechanics, treatment and published results available to present. It is hoped that such knowledge will diversify therapeutic options for the clinician, thereby improving outcomes in a small but not negligible portion of patients with previously unexplained persistent symptoms. PMID:27011843

  14. Chondrosarcoma of the Hip.

    PubMed

    Sperier, Aubrey D; Hammel, Nathan C; Rosenthal, Michael D

    2015-10-01

    The patient was a 27-year-old woman who was being evaluated by a physical therapist 1 month following a right Achilles tendon repair. She reported the presence of a painful firm mass in her left hip that she first noticed approximately 6 months prior. As an initial assessment of the mass, the physical therapist ordered radiographs of the left hip, which revealed a mass projecting off the left lateral iliac bone. The radiologist recommended contrast-enhanced magnetic resonance imaging for further characterization, which revealed a large lobulated mass that was consistent with an osteochondroma. PMID:26424575

  15. Lessons learnt from metal-on-metal hip arthroplasties will lead to safer innovation for all medical devices.

    PubMed

    Hart, Alister J; Sabah, Shiraz A; Henckel, Johann; Lloyd, Gwynneth; Skinner, John A

    2015-01-01

    Metal-on-metal bearings were re-popularised in the late 1990s with the introduction of modern hip resurfacing. Large diameter (LD) metal-on-metal (MoM) hips became more prevalent and have been the least successful group of hip implants ever used. They were rapidly adopted from 2004 until the British Hip Society stopped their use in 2012. Well functioning MoM hip results (including the BHR and Metasul) are hidden in the mire of poor results from the group of all MoM bearings.We have reviewed what happened and we make 3 observations. Firstly, collaboration between surgeons and then between surgeons and other disciplines, first identified and then solved the clinical management problems. Secondly, the problems with MoM hips occurred because hip simulation was inadequate at predicting performance in patients. They gave no indications of the biological effects of wear in the human environment. Lastly, retrieval of failed implants was essential to understanding why failure occurred.These lessons must never be forgotten and must form the basis by which new or altered implants are introduced and how they should be monitored. This will enable safer innovation for patients, surgeons and manufacturers. The problems with MoM hips will not have been in vain. PMID:26165359

  16. Management of the 'young' patient with hip disease.

    PubMed

    Ritterman, Scott A; Rubin, Lee E

    2013-03-01

    Although hip arthritis typically affects older patients, there is a rapidly growing population of "young" patients experiencing debilitating symptoms from hip disease. Most commonly, osteoarthritis and avascular necrosis affect this population, but a variety of other primary structural and metabolic causes can also occur. The expectations of these younger patients are often distinct from geriatric patients, and the challenges in optimizing their care are unique in this demanding population. Selection of the implant, bearing surface, and surgical technique can all impact the success and longevity of total hip replacement. A consideration for respecting the native bone stock is an important consideration that can potentially reduce some of the future challenges of revision arthroplasty in this young population. PMID:23641435

  17. Use of Cemented Spacer with a Handmade Stem to Treat Acute Periprosthetic Tibial Fracture Infection: A Case Report

    PubMed Central

    Font-Vizcarra, LluÍs; Izquierdo, Oscar; GarcÍa-NuÑo, Laura; GonzÁlez, Araceli; Diaz-Brito, VicenÇ; Castellanos, Juan

    2014-01-01

    We report an 85-year-old woman with dementia and dependent for normal life activities who was admitted due to a left periprosthetic tibial fracture. The tibial component was replaced by one with a long stem and she was discharged. Four weeks after the intervention the patient was re-admitted due to an acute prosthetic joint infection. All the components were removed and a bone-cement spacer with a handmade stem with a metal core was implanted. Radiological signs of fracture consolidation were observed after 3 months of follow-up. Due to the previous health status of the patient, it was decided to keep the spacer as a definitive treatment. After 24 months, the patient was able to sit without pain and to stand up with help using a knee brace. There were no radiological or clinical signs of infection. PMID:24551027

  18. Impingement in Total Hip Replacement: Mechanisms and Consequences

    PubMed Central

    Brown, Thomas D.; Callaghan, John J.

    2009-01-01

    The occurrence of total hip impingement, whether or not accompanied by frank dislocation, holds substantial untoward clinical consequences, especially as less-forgiving advanced bearing implant designs come into ever more widespread use. Biomechanical aspects of impingement and dislocation have historically received relatively little scientific attention, although that situation is now rapidly changing. The present article reviews contemporary laboratory and clinical research on the impingement/dislocation phenomena, focusing particularly on how implant design variables, surgical implantation factors and patient activity each act individually and in concert to pose impingement and dislocation challenges. In recent years, several powerful new research methodologies have emerged that have greatly expanded the scope for clinical translation of systematic laboratory study. Transferring the findings from such research into yet better implant designs, and even better surgical procedures, offers encouragement that the clinical impact of this troublesome complication can be further reduced. PMID:19956356

  19. In vivo kinematic evaluation of total hip arthroplasty during stair climbing.

    PubMed

    Dimitriou, Dimitris; Tsai, Tsung-Yuan; Li, Jing-Sheng; Nam, Kwang Woo; Park, Kwan Kyu; Kwon, Young-Min

    2015-07-01

    Stair climbing is a physically demanding task and a painful limitation for patients suffering from severe hip osteoarthritis. Although total hip arthroplasty (THA) is the definitive treatment for end-stage osteoarthritis, it is not well understood whether THA restores hip kinematics during strenuous activities. The purpose of this study was to compare the 3D kinematics of THA and native hip during physically demanding tasks and correlate potential differences with THA components orientations/positions in patients with unilateral THA. In vivo hip kinematics were determined during step-up and leg stance activities using a validated combination of 3D CT-based computer modeling and dual fluoroscopic imaging system (DFIS). The THA side demonstrated an average 3.4 (6.5, range: -5.9 to 15.2) greater internal rotation than the contralateral native hip, during the step-up activity but not during leg stance. The difference in internal rotation was highly correlated to the difference in femoral anteversion and anterior translation of hip joint center between implanted and native hip (R(2) ?=?0.71, p?hip kinematics during functional activities. PMID:25626860

  20. Ceramic on ceramic hip arthroplasty in fused hips

    PubMed Central

    Park, Kyung-Soon; Yoon, Taek-Rim; Lee, Tae-Min; Ahn, Yeong-Seub

    2015-01-01

    Background: Most literature in the field of total hip arthroplasty (THA) for fused hips, until date has reported the results of using metal on polyethylene and ceramic on polyethylene bearings. Results of THA using ceramic on ceramic (CoC) bearings in fused hips have not been published in literature. This study reports the results of cementless THA using CoC articulation perfomed in fused hips. Materials and Methods: Twenty-three patients (25 hips) with fused hips underwent conversion to THA using CoC bearings and were followed up for a mean 5.4 years. The conventional posterolateral approach was used in 15 hips, a modified two incision technique in 7 hips and a direct lateral approach with greater trochanteric osteotomy in 3 hips. Postoperatively, range of motion exercises were encouraged after 2–3 days of bed rest and subsequent gradual weight bearing using crutches was begun. Results: Mean Harris hip score improved from 42.4 to 84.2 and mean leg lengthening of 36.6 mm was achieved. In the average 5.4 years (range 2.8-9.1 years) followup there were no cases with osteolysis around acetabular cup and femoral stem. In this study, there was no case of ceramic fracture. There was one case of squeaking. Conclusion: This study suggests that cementless THA performed for fused hips with CoC bearings can provide good early clinical results. PMID:26015635

  1. Cochlear Implants

    MedlinePlus

    ... children receive a cochlear implant followed by intensive therapy before 18 months of age, they are better able to hear, comprehend sound and music, and speak than their peers who receive implants ...

  2. Cochlear Implants

    MedlinePlus

    A cochlear implant is a small, complex electronic device that can help to provide a sense of sound. People who are ... of-hearing can get help from them. The implant consists of two parts. One part sits on ...

  3. Carmustine Implant

    MedlinePlus

    Carmustine implant is used along with surgery and sometimes radiation therapy to treat malignant glioma (a certain type of ... Carmustine implant comes as a small wafer that is placed in the brain by a doctor during surgery to ...

  4. Cochlear implant

    MedlinePlus

    Brown KD, Balkany TJ. Benefits of bilateral cochlear implantation: a review. Curr Opin Otolaryngol Head Neck Surg . ... 17823546 . Limb CJ, Francis HW, Niparko JK. Cochlear implantation. In: Flint PW, Haughey BH, Lund LJ, et ...

  5. Modularity of the femoral component in total hip arthroplasty.

    PubMed

    Srinivasan, Anand; Jung, Edward; Levine, Brett Russell

    2012-04-01

    Modular femoral components have been developed to aid in recreating native femoral version, limb length, and offset in total hip arthroplasty. Use of modular implants results in cost savings, as well. Inventory can be reduced while allowing intraoperative flexibility and options. With modular implants, the femoral prosthesis can be built in situ, which is helpful in minimizing incision length and surgical dissection. However, additional modular junctions are associated with increased concern for component failure through taper fretting, fatigue fracture, and local corrosion, which may contribute to elevated serum metal ion levels. The recent trend toward using larger diameter femoral heads may impart higher loads and stress than were seen previously. Although modular components offer a plethora of intraoperative options in primary and revision total hip arthroplasty, the long-term effects of these additional junctions remains unknown. PMID:22474091

  6. Preclinical Evaluation of Bioabsorbable Polyglycolic Acid Spacer for Particle Therapy

    SciTech Connect

    Akasaka, Hiroaki; Sasaki, Ryohei; Miyawaki, Daisuke; Mukumoto, Naritoshi; Sulaiman, Nor Shazrina Binti; Nagata, Masaaki; Yamada, Shigeru; Murakami, Masao; Demizu, Yusuke; Fukumoto, Takumi

    2014-12-01

    Purpose: To evaluate the efficacy and safety of a polyglycolic acid (PGA) spacer through physical and animal experiments. Methods and Materials: The spacer was produced with surgical suture material made of PGA, forming a 3-dimensional nonwoven fabric. For evaluation or physical experiments, 150-MeV proton or 320-MeV carbon-ion beams were used to generate 60-mm width of spread-out Bragg peak. For animal experiments, the abdomens of C57BL/6 mice, with or without the inserted PGA spacers, were irradiated with 20 Gy of carbon-ion beam (290 MeV) using the spread-out Bragg peak. Body weight changes over time were scored, and radiation damage to the intestine was investigated using hematoxylin and eosin stain. Blood samples were also evaluated 24 days after the irradiation. Long-term thickness retention and safety were evaluated using crab-eating macaques. Results: No chemical or structural changes after 100 Gy of proton or carbon-ion irradiation were observed in the PGA spacer. Water equivalency of the PGA spacer was equal to the water thickness under wet condition. During 24 days' observation after 20 Gy of carbon-ion irradiation, the body weights of mice with the PGA spacer were relatively unchanged, whereas significant weight loss was observed in those mice without the PGA spacer (P<.05). In mice with the PGA spacer, villus and crypt structure were preserved after irradiation. No inflammatory reactions or liver or renal dysfunctions due to placement of the PGA spacer were observed. In the abdomen of crab-eating macaques, thickness of the PGA spacer was maintained 8 weeks after placement. Conclusions: The absorbable PGA spacer had water-equivalent, bio-compatible, and thickness-retaining properties. Although further evaluation is warranted in a clinical setting, the PGA spacer may be effective to stop proton or carbon-ion beams and to separate normal tissues from the radiation field.

  7. The athlete's hip and groin.

    PubMed

    Tammareddi, Kumar; Morelli, Vincent; Reyes, Miguel

    2013-06-01

    Groin and hip injuries are seen in athletes who perform quick directional changes and cutting movements. Because forces generated through athletic performance are transferred through the hip, injuries to these areas may limit athletes with mild pain or lead to career-ending injuries. The anatomy of the hip and groin is complex and symptoms often overlap. This article discusses some athletic causes, but other medical conditions may be associated with hip and groin pain as well. Updates in evaluation and treatment are discussed for adductor strains, hip osteoarthritis, femoroacetabular impingement, sports hernia, osteitis pubis, and obturator nerve entrapment. PMID:23668647

  8. Early Attempts at Hip Arthroplasty

    PubMed Central

    Gomez, Pablo F; Morcuende, Jose A

    2005-01-01

    Over the last three centuries, treatment of hip arthritides has evolved from rudimentary surgery to modern total hip arthroplasty (THA), which is considered one of the most successful surgical interventions ever developed. We here review the history of the early hip arthroplasty procedures for hip arthritis that preceded Charley total hip arthroplasty. An evaluation of such past enterprises is relevant, and reminds us of the ephemeral nature of human industriousness, and how medical research and procedures are not isolated developments, but correlate to the social, economical, and cultural framework of their time. PMID:16089067

  9. Hip Morphology Characterization

    PubMed Central

    Barrientos, Cristián; Diaz, Jorge; Brañes, Julian; Chaparro, Felipe; Barahona, Maximiliano; Salazar, Alfonso; Hinzpeter, Jaime

    2014-01-01

    Background: Femoroacetabular impingement (FAI) is the result of a mechanical conflict in the hip joint, and its diagnosis is based on clinical and radiological parameters. To our knowledge, there are no published studies describing the radiologic characteristics of FAI in Latin American populations. Purpose: To describe the radiological features associated with FAI in an asymptomatic Chilean population. Study Design: Cross-sectional study; Level of evidence, 3. Methods: We prospectively recruited asymptomatic patients with no history or symptoms of hip pathology who underwent abdomen-pelvis computed tomography (CT) for a nonorthopaedic indication. The acetabular and femoral parameters related to FAI were measured. Results: We studied 101 subjects (202 hips) with a mean age of 36.8 ± 14.4 years. The mean center-edge angle was 39.4° ± 7.2°. The crossover sign was present in 34 cases (33.7%). The mean alpha angle was 49.7° ± 8.3°. Depending on the cut points chosen for FAI-related parameters, between 39.6% and 69.3% of an asymptomatic Chilean population were found to have morphological features related to FAI. Conclusion: Our findings suggest that the proposed pathological threshold values in the literature cannot be extrapolated to a Chilean population, and this must be taken into consideration when evaluating Latin American patients with hip pain. PMID:26535273

  10. COMPLICATIONS IN HIP ARTHROSCOPY

    PubMed Central

    Contreras, Marcos Emílio Kuschnaroff; Hoffmann, Rafael Barreiros; de Araújo, Lúcio Cappelli Toledo; Dani, William Sotau; José Berral, Francisco

    2015-01-01

    Objectives: To determine the prevalence of complications in a series of consecutive cases of hip arthroscopy; to assess the progression of the sample through a learning curve; and to recognize the causes of complications in arthroscopic hip operations. Method: 150 consecutive cases that underwent hip arthroscopy between May 2004 and December 2008 were evaluated. The complications encountered were classified in three ways: organic system affected, severity and groups of 50 consecutive cases. The data were analyzed by means of descriptive statistics and Fisher's exact test. Results: We observed 15 complications in this study (10%): ten were neurological, two were osteoarticular, one was vascular-ischemic and two were cutaneous. In the classification of severity, three were classified as major, 12 as intermediate and none as minor. The incidence of complications over the course of the learning curve did not present any statistically significant difference (p = 0.16). Conclusions: Hip arthroscopy is a surgical procedure that involves low morbidity, but which presents complications in some cases. These complications are frequently neurological and transitory, and mainly occur because of joint traction. The complication rate did not decrease with progression of our sample. PMID:27022521

  11. INL HIP Plate Fabrication

    SciTech Connect

    B. H. Park; C. R. Clark; J. F. Jue

    2010-02-01

    This document outlines the process used to bond monolithic fuel plates by Hot Isostatic Pressing (HIP). This method was developed at Idaho National Laboratory (INL) for the Reduced Enrichment for Research and Test Reactors (RERTR) program. These foils have been used in a number of irradiation experiments in support of the United States Global Threat Reduction Initiative (GTRI) program.

  12. Unusual prosthetic femoral head fracture in total hip arthroplasty: ceramic on polyethylene articulation

    PubMed Central

    Tucker, Damien; Acharya, Mehool

    2014-01-01

    A 68-year-old man with a previous right total hip arthroplasty presented with acute pain in the right hip, and no associated trauma was reported. The previous hybrid arthroplasty consisted of a ceramic femoral head articulating on an ultra-high-molecular-weight polyethylene liner. The unusual diagnosis of fractured ceramic femoral head was made and an urgent revision arthroplasty was performed to remove the ceramic bearing as well as all implants that may have come into contact with the ceramic. This case report highlights the material properties of ceramics in total hip arthroplasties as well as the importance of regular follow-up in these patients. PMID:24515234

  13. Clinical Outcomes Assessment of Three Similar Hip Arthroplasty Bearing Surfaces

    PubMed Central

    Parsons, Christopher; Batson, Ryan; Reighard, Shane; Tanner, Stephanie; Snider, Becky; Pace, Thomas B.

    2014-01-01

    This report examines the clinical performance of three very similar total hip arthroplasty designs with distinctly different bearing surfaces used over the course 10-17 years. Clinical outcomes assessments for each group are compared in the context of varying implant related costs related to the latest technology at the time of surgery. Eighty-one surgeries were studied and differ by bearing surface. In this study, 36 hips are ceramic on polyethylene, 27 are metal on polyethylene and 18 are metal on metal. All polyethylene components are nonhighly cross-linked. The ceramic on polyethylene group has younger patients, on average, and higher percentage of patients with significant polyethylene wear. These groups have an average follow-up time of 8.6 years when assessing functional hip scores, thigh pain, groin pain, revision surgeries and radiographic osteolysis. The implant purchasing cost at the time of surgery was assessed to determine if a correlation exists between outcomes and the more technologically advanced implants use at the time of surgery. Based on midterm clinical outcome assessment, no correlation between initial hospital cost and clinical outcomes of one bearing surface over another can be found. PMID:25002938

  14. Two-stage revision arthroplasty for management of chronic periprosthetic hip and knee infection: techniques, controversies, and outcomes.

    PubMed

    Kuzyk, Paul R T; Dhotar, Herman S; Sternheim, Amir; Gross, Allan E; Safir, Oleg; Backstein, David

    2014-03-01

    In North America, two-stage revision arthroplasty is the treatment of choice for chronic periprosthetic infection of the hip and knee. Controversy exists regarding the diagnosis of persistent infection, cement spacer design, and duration of antibiotic therapy. Erythrocyte sedimentation rate and C-reactive protein tests have no clear cutoff values for detecting infection before reimplantation of hardware, and aspiration for microbial culture can yield false-negative results. Mobile spacers are as effective as static spacers for eradicating infection, but mobile spacers provide better interim function and may help to make the second stage of surgery technically easier. Some articulating spacer designs have fewer reports of spacer dislocation and fracture than do others. Although prolonged antibiotic therapy has been the standard of care for two-stage procedures, some have suggested that a short course of antibiotics is just as effective. When infection persists despite antibiotic therapy, the second stage of revision arthroplasty should be delayed until the first stage of the procedure is repeated. PMID:24603825

  15. Total Hip Replacement for the Treatment of End Stage Arthritis of the Hip: A Systematic Review and Meta-Analysis

    PubMed Central

    Tsertsvadze, Alexander; Grove, Amy; Freeman, Karoline; Court, Rachel; Johnson, Samantha; Connock, Martin; Clarke, Aileen; Sutcliffe, Paul

    2014-01-01

    Background Evolvements in the design, fixation methods, size, and bearing surface of implants for total hip replacement (THR) have led to a variety of options for healthcare professionals to consider. The need to determine the most optimal combinations of THR implant is warranted. This systematic review evaluated the clinical effectiveness of different types of THR used for the treatment of end stage arthritis of the hip. Methods A comprehensive literature search was undertaken in major health databases. Randomised controlled trials (RCTs) and systematic reviews published from 2008 onwards comparing different types of primary THR in patients with end stage arthritis of the hip were included. Results Fourteen RCTs and five systematic reviews were included. Patients experienced significant post-THR improvements in Harris Hip scores, but this did not differ between impact types. There was a reduced risk of implant dislocation after receiving a larger femoral head size (36 mm vs. 28 mm; RR = 0.17, 95% CI: 0.04, 0.78) or cemented cup (vs. cementless cup; pooled odds ratio: 0.34, 95% CI: 0.13, 0.89). Recipients of cross-linked vs. conventional polyethylene cup liners experienced reduced femoral head penetration and revision. There was no impact of femoral stem fixation and cup shell design on implant survival rates. Evidence on mortality and complications (aseptic loosening, femoral fracture) was inconclusive. Conclusions The majority of evidence was inconclusive due to poor reporting, missing data, or uncertainty in treatment estimates. The findings warrant cautious interpretation given the risk of bias (blinding, attrition), methodological limitations (small sample size, low event counts, short follow-up), and poor reporting. Long-term pragmatic RCTs are needed to allow for more definitive conclusions. Authors are encouraged to specify the minimal clinically important difference and power calculation for their primary outcome(s) as well CONSORT, PRISMA and STROBE guidelines to ensure better reporting and more reliable production and assessment of evidence. PMID:25003202

  16. Surface-Tethered Iterative Carbohydrate Synthesis (STICS): A spacer study

    PubMed Central

    Ganesh, N. Vijaya; Fujikawa, Kohki; Tan, Yih Horng; Nigudkar, Swati S.

    2013-01-01

    Comparative study of STICS using HPLC-assisted experimental set-up clearly demonstrated benefits of using longer spacer-anchoring systems. The use of mixed self-assembled monolayers helps to provide the required space for glycosylation reaction around the immobilized glycosyl acceptor. Both extension of the spacer length and using mixed self-assembled monolayers help to promote reaction and the beneficial effects may include moving the glycosyl acceptor further out into solution and providing additional conformational flexibility. It is possible that surface-immobilized glycosyl acceptors with a longer spacer (C8-O-C8)-lipoic acid have a higher tendency to mimic a solution-phase reaction environment than that of acceptors with shorter spacers. PMID:23822088

  17. 14. TYPICAL WORK DECK SHOWING RING SPACERS, CABLE DRUMS AND ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. TYPICAL WORK DECK SHOWING RING SPACERS, CABLE DRUMS AND OTHER SPECIALIZED HARDWARE; VIEW TO SOUTH. - Cape Canaveral Air Station, Launch Complex 17, Facility 28416, East end of Lighthouse Road, Cape Canaveral, Brevard County, FL

  18. A Systematic Study of RPC Spacer Bond Strength for PHENIX

    NASA Astrophysics Data System (ADS)

    Kish, Joseph

    2008-10-01

    The Pioneering High Energy Nuclear Interaction eXperiment at Brookhaven National Laboratory is currently undergoing a forward muon trigger upgrade by incorporating large Resistive Plate Chamber tracking stations. The upgrade will make it possible to determine the spin contributions of sea and valence quarks to the spin of the proton. Many aspects of the PHENIX RPC design were borrowed from the Compact Muon Solenoid experiment at CERN. Unfortunately, approximately 5% of CMS gas gaps had gas leaks or failed spacer integrity testing. In order to address the problem of spacer failure, a systematic study of spacer-epoxy-Bakelite bond strength was conducted. Several tests were performed in order to determine the relationship, if any, between various surface treatments, curing temperature, spacer geometry and bond strength. The methods, results and improvements will be discussed.

  19. Total hip replacement in young adults with hip dysplasia

    PubMed Central

    2011-01-01

    Background and purpose Dysplasia of the hip increases the risk of secondary degenerative change and subsequent total hip replacement. Here we report on age at diagnosis of dysplasia, previous treatment, and quality of life for patients born after 1967 and registered with a total hip replacement due to dysplasia in the Norwegian Arthroplasty Register. We also used the medical records to validate the diagnosis reported by the orthopedic surgeon to the register. Methods Subjects born after January 1, 1967 and registered with a primary total hip replacement in the Norwegian Arthroplasty Register during the period 1987–2007 (n = 713) were included in the study. Data on hip symptoms and quality of life (EQ-5D) were collected through questionnaires. Elaborating information was retrieved from the medical records. Results 540 of 713 patients (76%) (corresponding to 634 hips) returned the questionnaires and consented for additional information to be retrieved from their medical records. Hip dysplasia accounted for 163 of 634 hip replacements (26%), 134 of which were in females (82%). Median age at time of diagnosis was 7.8 (0–39) years: 4.4 years for females and 22 years for males. After reviewing accessible medical records, the diagnosis of hip dysplasia was confirmed in 132 of 150 hips (88%). Interpretation One quarter of hip replacements performed in patients aged 40 or younger were due to an underlying hip dysplasia, which, in most cases, was diagnosed during late childhood. The dysplasia diagnosis reported to the register was correct for 88% of the hips. PMID:21434808

  20. Two-Stage Revision Using a Modified Articulating Spacer in Infected Total Knee Arthroplasty

    PubMed Central

    Kim, Young Soo; Cho, Chul Hyun; Lee, Kyung Jae; Sohn, Eun Seok; Kim, Beom Soo

    2013-01-01

    Purpose To evaluate clinical results of two-stage revision using a modified articulating spacer for treatment of infected total knee arthroplasty (TKA). Materials and Methods We retrospectively reviewed 20 cases treated by two-stage revision arthroplasty using a modified articulating spacer under the diagnosis of infected TKA from January 2006 to December 2011. The mean follow-up period was 22.3 months. The first operation consisted of debridement after removal of the prosthesis, reinsertion of the femoral component after autoclaving, and implantation of antibiotic-loaded cement with a new polyethylene in the proximal tibia. Results The mean period between the primary TKA and the first stage operation was 39 months and between the first stage operation and the revision arthroplasty was 3.3 months. The average range of motion (ROM) increased from 69.8° preoperatively to 102.8° postoperatively (p<0.001). The mean Knee Society knee score increased from 33.8 points to 85.3 points (p<0.001). The mean Knee Society function score increased from 35 points to 87.5 points (p<0.001). The mean Hospital for Special Surgery score increased from 57.6 points preoperatively to 82.6 points postoperatively (p<0.001). Two cases (10%) were re-infected after the revision arthroplasty. Conclusions Two-stage revision arthroplasty using an articulating cement spacer can be an effective therapy not only for the treatment of an infected TKA but also for recovery of knee ROM and function. PMID:24368995

  1. Bioinformatics analyses of Shigella CRISPR structure and spacer classification.

    PubMed

    Wang, Pengfei; Zhang, Bing; Duan, Guangcai; Wang, Yingfang; Hong, Lijuan; Wang, Linlin; Guo, Xiangjiao; Xi, Yuanlin; Yang, Haiyan

    2016-03-01

    Clustered regularly interspaced short palindromic repeats (CRISPR) are inheritable genetic elements of a variety of archaea and bacteria and indicative of the bacterial ecological adaptation, conferring acquired immunity against invading foreign nucleic acids. Shigella is an important pathogen for anthroponosis. This study aimed to analyze the features of Shigella CRISPR structure and classify the spacers through bioinformatics approach. Among 107 Shigella, 434 CRISPR structure loci were identified with two to seven loci in different strains. CRISPR-Q1, CRISPR-Q4 and CRISPR-Q5 were widely distributed in Shigella strains. Comparison of the first and last repeats of CRISPR1, CRISPR2 and CRISPR3 revealed several base variants and different stem-loop structures. A total of 259 cas genes were found among these 107 Shigella strains. The cas gene deletions were discovered in 88 strains. However, there is one strain that does not contain cas gene. Intact clusters of cas genes were found in 19 strains. From comprehensive analysis of sequence signature and BLAST and CRISPRTarget score, the 708 spacers were classified into three subtypes: Type I, Type II and Type III. Of them, Type I spacer referred to those linked with one gene segment, Type II spacer linked with two or more different gene segments, and Type III spacer undefined. This study examined the diversity of CRISPR/cas system in Shigella strains, demonstrated the main features of CRISPR structure and spacer classification, which provided critical information for elucidation of the mechanisms of spacer formation and exploration of the role the spacers play in the function of the CRISPR/cas system. PMID:26867599

  2. Spacer process and alignment assessment for SADP process

    NASA Astrophysics Data System (ADS)

    Lattard, L.; McCallum, M.; Morton, R.; Fujiwara, T.; Makino, K.; Tokui, A.; Takahashi, N.; Sasamoto, S.

    2012-03-01

    Self Aligned Double Patterning (SADP) is now widely accepted as a viable technology for the further extension of 193nm immersion lithography towards the 22nm /18nm technology nodes. SADP was primary introduced for the manufacturing of flash memory due to its 1D design geometry. However, SADP is now becoming a main stream technology for advanced technology nodes for logic product. SADP results in alignment marks with reduced image contrast after completion of spacer patterning. Consequently there is an elevated risk that the alignment performance of the cut lithography layer on the spacer [1] may be negatively impacted. Initial studies indicate that it may be necessary to consider new mark designs. In this paper, we will evaluate different types of SADP processes with the alignment system of the Nikon S620D and S621D immersion scanner. We will discuss the performances and the differences observed due to the SADP materials. Included in this study is an intensive characterization of the morphology of the spacer after SADP process. We will use for this a 3D-AFM from Insight, and characterize the spacer profile of the spacer. Using a standard AFM microscope, we can characterize the surface roughness in the inner and the outer part of the wafer. The self aligned spacer process results in asymmetric spacers. Two types of surface (inside and outside) of the spacer are formed. The impact of this asymmetry is also assessed. The roughness difference, between the two parts, will play an important roll in the alignment contrast.

  3. Bone cement implantation syndrome: a delayed postoperative presentation.

    PubMed

    Singh, Vikash; Bhakta, Pradipta; Zietak, Edyta; Hussain, Ashfaq

    2016-06-01

    Bone cement implantation syndrome (BCIS) is a well-known entity but is poorly understood and rarely reported. It is an important cause of perioperative morbidity and mortality in the patient undergoing cemented hip arthroplasty. BCIS is characterized by hypotension, hypoxia, cardiac arrhythmias, and increased pulmonary vascular resistance and can lead to eventual cardiac arrest if not managed properly. We hereby report a case of delayed presentation of BCIS following cemented right hip arthroplasty. PMID:27185726

  4. Nuclear reactor spacer grid and ductless core component

    DOEpatents

    Christiansen, David W.; Karnesky, Richard A.

    1989-01-01

    The invention relates to a nuclear reactor spacer grid member for use in a liquid cooled nuclear reactor and to a ductless core component employing a plurality of these spacer grid members. The spacer grid member is of the egg-shell type and is constructed so that the walls of the cell members of the grid member are formed of a single thickness of metal to avoid tolerance problems. Within each cell member is a hydraulic spring which laterally constrains the nuclear material bearing rod which passes through each cell member against a hardstop in response to coolant flow through the cell member. This hydraulic spring is also suitable for use in a water cooled nuclear reactor. A core component constructed of, among other components, a plurality of these spacer grid members, avoids the use of a full length duct by providing spacer sleeves about the sodium tubes passing through the spacer grid members at locations between the grid members, thereby maintaining a predetermined space between adjacent grid members.

  5. Sidewall spacer optimization for steep switching junctionless transistors

    NASA Astrophysics Data System (ADS)

    Gupta, Manish; Kranti, Abhinav

    2016-06-01

    In this work, we analyze the impact of a high permittivity (high-κ) sidewall spacer and gate dielectric on the occurrence of sub-60 mV/decade subthreshold swing (S-swing) in symmetrical junctionless (JL) double gate (DG) transistors. It is shown that steep S-swing values (≤10 mV/decade) can be achieved in JL devices with a combination of a high permittivity (high-κ) gate dielectric and a narrow low permittivity (low-κ) sidewall spacer. Implementation of a wider high-κ spacer will diminish the degree of impact ionization by the influence of the fringing component of the gate electric field, and will not be useful for steep off-to-on current transition. A wider spacer with low-κ and a narrow spacer with high-κ permittivity will be useful to limit the latching effect that can occur at lower temperatures (250 K). For high temperature operation, the decrease in the impact ionization rate can be compensated by designing a JL transistor with a thicker silicon film. The work demonstrates opportunities to enhance impact ionization at sub bandgap voltages, and proposes optimal guidelines for selecting a sidewall spacer to facilitate steep switching in JL transistors.

  6. Influence of prosthesis design and implantation technique on implant stresses after cementless revision THR

    PubMed Central

    2011-01-01

    Background Femoral offset influences the forces at the hip and the implant stresses after revision THR. For extended bone defects, these forces may cause considerable bending moments within the implant, possibly leading to implant failure. This study investigates the influences of femoral anteversion and offset on stresses in the Wagner SL revision stem implant under varying extents of bone defect conditions. Methods Wagner SL revision stems with standard (34 mm) and increased offset (44 mm) were virtually implanted in a model femur with bone defects of variable extent (Paprosky I to IIIb). Variations in surgical technique were simulated by implanting the stems each at 4° or 14° of anteversion. Muscle and joint contact forces were applied to the reconstruction and implant stresses were determined using finite element analyses. Results Whilst increasing the implant's offset by 10 mm led to increased implant stresses (16.7% in peak tensile stresses), altering anteversion played a lesser role (5%). Generally, larger stresses were observed with reduced bone support: implant stresses increased by as much as 59% for a type IIIb defect. With increased offset, the maximum tensile stress was 225 MPa. Conclusion Although increased stresses were observed within the stem with larger offset and increased anteversion, these findings indicate that restoration of offset, key to restoring joint function, is unlikely to result in excessive implant stresses under routine activities if appropriate fixation can be achieved. PMID:21569522

  7. Is reverse hybrid hip replacement the solution?

    PubMed Central

    2011-01-01

    Background and purpose Reverse hybrid hip replacement uses a cemented all-polyethylene cup and an uncemented stem. Despite increasing use of this method in Scandinavia, there has been very little documentation of results. We have therefore analyzed the results from the Norwegian Arthroplasty Register (NAR), with up to 10 years of follow-up. Patients and methods The NAR has been collecting data on total hip replacement (THR) since 1987. Reverse hybrid hip replacements were used mainly from 2000. We extracted data on reverse hybrid THR from this year onward until December 31, 2009, and compared the results with those from cemented implants over the same period. Specific cup/stem combinations involving 100 cases or more were selected. In addition, only combinations that were taken into use in 2005 or earlier were included. 3,963 operations in 3,630 patients were included. We used the Kaplan-Meier method and Cox regression analysis for estimation of prosthesis survival and relative risk of revision. The main endpoint was revision for any cause, but we also performed specific analyses on different reasons for revision. Results We found equal survival to that from cemented THR at 5 years (cemented: 97.0% (95% CI: 96.8–97.2); reverse hybrid: 96.7% (96.0–97.4)) and at 7 years (cemented: 96.0% (95.7–96.2); reverse hybrid: 95.6% (94.4–96.7)). Adjusted relative risk of revision of the reverse hybrids was 1.1 (0.9–1.4). In patients under 60 years of age, we found similar survival of the 2 groups at 5 and 7 years, with an adjusted relative risk of revision of reverse hybrids of 0.9 (0.6–1.3) compared to cemented implants. Interpretation With a follow-up of up to 10 years, reverse hybrid THRs performed well, and similarly to all-cemented THRs from the same time period. The reverse hybrid method might therefore be an alternative to all-cemented THR. Longer follow-up time is needed to evaluate whether reverse hybrid hip replacement has any advantages over all-cemented THR. PMID:21999624

  8. Alternative bearing surface options for revision total hip arthroplasty.

    PubMed

    Patel, Deepan; Parvizi, Javad; Sharkey, Peter F

    2011-01-01

    Despite the overall success of total hip arthroplasty (THA), there has been an increase in the rate of revision hip surgeries performed each year in the United States. These revision surgeries result in several billion dollars in health care costs. Bearing surface wear can result in the need for revision surgery through a variety of mechanisms. Many implant failures necessitating the need for revision surgeries occur secondary to dislocations, which are often related to prothesis wear and eventual loosening of the components. Wear also can lead to osteolysis and may play a role in aseptic loosening. Specific concerns regarding the wear rates of metal-on-polyethylene (the most common bearing surface) have encouraged the manufacture of newer polyethylene implants with improved wear properties, as well as alternative bearing surfaces. The goal is to improve the durability of revision implants and/or reduce the incidence of revision THAs. Revision arthroplasty involves using alternative surfaces, such as replacing the metal femoral head with a ceramic component or changing the entire prosthesis to a metal-on-metal or ceramic-on-ceramic articulation. It is important to review the characteristics of these alternative bearing surface options and their contributions to improved THA tribology and prolonged prosthesis longevity. The choice of a bearing surface for a revision THA should consider factors such as the patient's age and activity level, the cost of the implant, and both the surgeons' and patients' preferences. Although laboratory studies and small clinical trials have generated optimistic results for these alternative implants in vitro and in vivo, much still needs to be learned about the long-term performance of these materials in patients after total hip revision surgery. PMID:21553778

  9. [Computer-assisted surgery for hip endoprosthesis].

    PubMed

    Brner, M; Lahmer, A; Wiesel, U

    1999-06-01

    The use of computer-controlled robots for implanting cement-free prostheses requires exact preoperative planning on a three-dimensional graphics computer (ORTHODOC). For the first time ever, it has been possible to implement the three-dimensional plan using a computer-controlled robot working on patients. We assume that the considerably improved bone contact provided by the high-precision reaming process--an thus high primary stability--will lead to better incorporation in the bone. In experiments on dogs, in which cement-free hips had been implanted using computer-assisted robots, the animals showed much earlier and more uniform weight-bearing on the affected extremity than animals in a control group that had received conventional implants. In histological therms, the precise fit obtained by the ROBOCOC was accompanied by primary angiogenic healing patterns that all demonstrated labels during the first four weeks. The manually reamed comparators showed more pronounced fissure and defect healing, the healing patterns was irregular, and turnover activity was demonstrate. PMID:10432568

  10. Intra-articular hip injections for lateral hip pain

    PubMed Central

    Bessette, Matthew C.; Olsen, Joshua R.; Mann, Tobias R.; Giordano, Brian D.

    2014-01-01

    Occult intra-articular hip pathology is commonly found in patients with greater trochanteric pain syndrome, and may be a possible pain generator in patients with recalcitrant lateral hip pain. We investigated the effect of intra-articular hip injections in patients with recalcitrant lateral hip pain. Between September 2012 and May 2013, patients over the age of 18 with a history lateral hip pain who had received prior treatment with non-steroidal anti-inflammatory medications, physical therapy and peritrochanteric corticostroid injections were enrolled. Treatment consisted of an ultrasound guided intra-articular corticosteroid injection followed by a course of directed physical therapy and a non-steroidal anti-inflammatory medication. Patients performed GaitRite analysis at baseline and 12 weeks following the injection. In addition, the Modified Harris Hip Score (mHHS), Non-Arthritic Hip Score (NAHS), Hip Outcome Scores (HOS), Short Form 36 (SF-36) and a visual analogue pain score (VAS) were collected at baseline, 1, 6 and 12 weeks.A total of 16 patients were studied. Patients experienced significant improvements from their baseline mHHS at 1 and 12 weeks (P = 0.03, P = 0.04). The minimal clinically important difference (MCID) was exceeded at multiple timepoints on various clinical outcome surveys. Velocity and stride length were not significantly improved at 12 weeks. Intra-articular hip injections may decrease pain and improve function in patients with recalcitrant lateral hip pain, and occult intra-articular hip pathology should be considered in the etiology of lateral hip pain. Though low enrollment numbers left this study underpowered, MCID comparisons demonstrated potential benefit from this treatment. PMID:27011805

  11. Nonarthritic hip joint pain.

    PubMed

    Enseki, Keelan; Harris-Hayes, Marcie; White, Douglas M; Cibulka, Michael T; Woehrle, Judith; Fagerson, Timothy L; Clohisy, John C

    2014-06-01

    The Orthopaedic Section of the American Physical Therapy Association (APTA) has an ongoing effort to create evidence-based practice guidelines for orthopaedic physical therapy management of patients with musculoskeletal impairments described in the World Health Organization's International Classification of Functioning, Disability, and Health (ICF). The purpose of these clinical practice guidelines is to describe the peer-reviewed literature and make recommendations related to nonarthritic hip joint pain. PMID:24881906

  12. Implantable Microimagers

    PubMed Central

    Ng, David C.; Tokuda, Takashi; Shiosaka, Sadao; Tano, Yasuo; Ohta, Jun

    2008-01-01

    Implantable devices such as cardiac pacemakers, drug-delivery systems, and defibrillators have had a tremendous impact on the quality of live for many disabled people. To date, many devices have been developed for implantation into various parts of the human body. In this paper, we focus on devices implanted in the head. In particular, we describe the technologies necessary to create implantable microimagers. Design, fabrication, and implementation issues are discussed vis-à-vis two examples of implantable microimagers; the retinal prosthesis and in vivo neuro-microimager. Testing of these devices in animals verify the use of the microimagers in the implanted state. We believe that further advancement of these devices will lead to the development of a new method for medical and scientific applications.

  13. Constrained components for the unstable hip following total hip arthroplasty: a literature review

    PubMed Central

    Ragland, P. S.; Clarke, S.

    2006-01-01

    Patients with chronic instability or late dislocation following total hip arthroplasty often require operative management. Unfortunately, there is an increased risk of recurrent dislocation following revision in these patients. Over the past decade the use of constrained devices for patients with chronic instability has gained increased interest; however, there is a paucity of studies available in the literature regarding the use of these devices. The purpose of this study was to analyze the available literature over the past 15 years, focusing on larger, long-term studies, to obtain recommendations from the respective articles for indications and contraindications for the use of constrained devices. Our review of eight reports included 1,199 hips in 1,148 patients with a total mean follow-up of 51 months (range, 24 to 124 months). The mean rate of dislocation following revision with a constrained liner was 10% and the mean re-operation rate for reasons other than dislocation was 4%. We concluded that constrained liners are an option for patients who have failed management of instability with other implants, those with instability of unclear etiology, those with cognitive problems who are unable to follow dislocation precautions, those with deficient abductors, and elderly or low-demand individuals with well-positioned implants requiring revision. PMID:16927089

  14. The cement spacer with multiple indentations: increasing antibiotic elution using a cement spacer 'teabag'.

    PubMed

    Salih, S; Paskins, A; Nichol, T; Smith, T; Hamer, A

    2015-11-01

    We investigated whether the indentation of bone cement spacers used in revision of infected joint arthroplasty with a MacDonald dissector increased the elution of antibiotic in vitro. A total of 24 cement discs containing either 0.17 g (0.88% w/w), 0.25 g (1.41% w/w), or 0.33 g (1.75% w/w) gentamicin of constant size were made. Of these, 12 were indented with the dissector. Each disc was immersed in ammonium acetate buffer in a sealed container, and fluid from each container was sampled at zero, one, three, six, 24, 48 and 72 hours and at one, and two weeks. The concentration of gentamicin in the fluid was analysed using high performance liquid chromatography mass spectrometry. The fluid sampled at 72 hours from the indented discs containing 0.17 g gentamicin (0.88% w/w) contained a mean of 113 mcg/ml (90.12 to 143.5) compared with 44.5 mcg/ml (44.02 to 44.90) in the fluid sampled from the plain discs (p = 0.012). In discs containing 0.33 g gentamicin (1.75% w/w), the concentration eluted from the indented discs at 72 hours was a mean of 316 mcg/ml (223 to 421) compared with a mean of 118 mcg/ml (100 to 140) from the plain discs (p < 0.001). At two weeks, these significant differences persisted. At nine weeks the indented discs eluted a greater concentration for all gentamicin doses, but the difference was only significant for the discs containing 0.17 g (0.88% w/w, p = 0.006). However if the area under the curve is taken as a measure of the total antibiotic eluted, the indented discs eluted more gentamicin than the plain discs for the 0.17 g (0.88% w/w, p = 0.031), the 0.25 g (1.41% w/w, p < 0.001) and the 0.33 g (1.75% w/w, p < 0.001) discs. When preparing antibiotic spacers for use in staged revision arthroplasty surgery we recommend indenting the spacer with a MacDonald dissector to increase the elution of antibiotic. PMID:26530655

  15. Drug-Eluting Nasal Implants: Formulation, Characterization, Clinical Applications and Challenges

    PubMed Central

    Parikh, Ankit; Anand, Utkarshini; Ugwu, Malachy C.; Feridooni, Tiam; Massoud, Emad; Agu, Remigius U.

    2014-01-01

    Chronic inflammation and infection of the nasal sinuses, also referred to as Chronic Rhinosinusitis (CRS), severely affects patients’ quality of life. Adhesions, ostial stenosis, infection and inflammation relapses complicate chronic sinusitis treatment strategies. Drug-eluting stents, packings or implants have been suggested as reasonable alternatives for addressing these concerns. This article reviewed potential drug candidates for nasal implants, formulation methods/optimization and characterization methods. Clinical applications and important considerations were also addressed. Clinically-approved implants (Propel™ implant, the Relieva stratus™ MicroFlow spacer, and the Sinu-Foam™ spacer) for CRS treatment was an important focus. The advantages and limitations, as well as future considerations, challenges and the need for additional research in the field of nasal drug implant development, were discussed. PMID:24871904

  16. Drug-eluting nasal implants: formulation, characterization, clinical applications and challenges.

    PubMed

    Parikh, Ankit; Anand, Utkarshini; Ugwu, Malachy C; Feridooni, Tiam; Massoud, Emad; Agu, Remigius U

    2014-01-01

    Chronic inflammation and infection of the nasal sinuses, also referred to as Chronic Rhinosinusitis (CRS), severely affects patients' quality of life. Adhesions, ostial stenosis, infection and inflammation relapses complicate chronic sinusitis treatment strategies. Drug-eluting stents, packings or implants have been suggested as reasonable alternatives for addressing these concerns. This article reviewed potential drug candidates for nasal implants, formulation methods/optimization and characterization methods. Clinical applications and important considerations were also addressed. Clinically-approved implants (Propel implant, the Relieva stratus MicroFlow spacer, and the Sinu-Foam spacer) for CRS treatment was an important focus. The advantages and limitations, as well as future considerations, challenges and the need for additional research in the field of nasal drug implant development, were discussed. PMID:24871904

  17. Negligence claims in UK total hip arthroplasty: a series of 167 consecutive cases.

    PubMed

    Whittingham-Jones, Paul; Williams, D; Raja, S; Bridle, S; Bircher, M

    2012-01-01

    A review of negligence reports, detailing 227 complaints from the practices of two orthopedic surgeons, was undertaken. There were demonstrable differences in the number of complaints over leg-length discrepancy; femoral fracture and cup malposition when cemented versus uncemented implants were compared. Surgeons must appreciate the less forgiving nature of uncemented hip implants and the importance of preoperative planning particularly in the presence of abnormal anatomy. PMID:23341296

  18. High Productivity Implantation ''PARTIAL IMPLANT''

    SciTech Connect

    Hino, Masayoshi; Miyamoto, Naoki; Sakai, Shigeki; Matsumoto, Takao

    2008-11-03

    The patterned ion implantation 'PARTIAL IMPLANT' has been developed as a productivity improvement tool. The Partial Implant can form several different ion dose areas on the wafer surface by controlling the speed of wafer moving and the stepwise rotation of twist axis. The Partial Implant system contains two implant methods. One method is 'DIVIDE PARTIAL IMPLANT', that is aimed at reducing the consumption of the wafer. The Divide Partial Implant evenly divides dose area on one wafer surface into two or three different dose part. Any dose can be selected in each area. So the consumption of the wafer for experimental implantation can be reduced. The second method is 'RING PARTIAL IMPLANT' that is aimed at improving yield by correcting electrical characteristic of devices. The Ring Partial Implant can form concentric ion dose areas. The dose of wafer external area can be selected to be within plus or minus 30% of dose of wafer central area. So the electrical characteristic of devices can be corrected by controlling dose at edge side on the wafer.

  19. Modified Girdlestone arthroplasty and hip arthrodesis using the Ilizarov external fixator as a salvage method in the management of severely infected total hip replacement

    PubMed Central

    Kliushin, Nikolai M; Ababkov, Yuri V; Ermakov, Artem M; Malkova, Tatiana A

    2016-01-01

    Background: Resection arthroplasty or hip arthrodesis after total hip replacement (THR) can be used to salvage the limb in case with deep infection and severe bone loss. The Ilizarov fixator provides stability, axial correction, weight-bearing and good fusion rates. Materials and Methods: We retrospectively assessed the outcomes of 37 patients with severe periprosthetic infection after THR treated between 1999 and 2011. The treatment included implant removal, debridement and a modified Girdestone arthroplasty (29 cases) or hip arthrodesis (seven cases) using the Ilizarov fixator. The Ilizarov fixation continued from 45 to 50 days in the modified arthroplasty group and 90 days in the arthrodesis group. One case was treated using the conventional resection arthroplasty bilaterally. Results: Eighteen months after treatment, infection control was seen in 97.3% cases. Six hips were fused as one patient died in this group. Limb length discrepancy (LLD) averaged 5.5 cm. The Harris hip score ranged from 35 to 92 points. Hip joint motion ranged from 10° to 30° in the modified arthroplasty group. All subjects could walk independently or using support aids. No subluxation or LLD progression was observed. Conclusion: The modified Girdlestone arthroplasty and hip arthrodesis using the Ilizarov apparatus results in sufficient ability for ambulation and good infection control in cases of failed THR associated with severe infection. PMID:26955173

  20. Heterotopic ossification after hip arthroscopy

    PubMed Central

    Amar, Eyal; Sharfman, Zachary T.; Rath, Ehud

    2015-01-01

    Heterotopic ossification (HO) after hip arthroscopy is the abnormal formation of mature lamellar bone within extra skeletal soft tissues. HO may lead to pain, impaired range of motion and possibly revision surgery. There has been a substantial amount of recent research on the pathophysiology, prophylaxis and treatment of HO associated with open and arthroscopic hip surgery. This article reviews the literature on the aforementioned topics with a focus on their application in hip arthroscopy. PMID:27011859

  1. Endodontic implants.

    PubMed

    Yadav, Rakesh K; Tikku, A P; Chandra, Anil; Wadhwani, K K; Ashutosh Kr; Singh, Mayank

    2014-01-01

    Endodontic implants were introduced back in 1960. Endodontic implants enjoyed few successes and many failures. Various reasons for failures include improper case selection, improper use of materials and sealers and poor preparation for implants. Proper case selection had given remarkable long-term success. Two different cases are being presented here, which have been treated successfully with endodontic implants and mineral trioxide aggregate Fillapex (Andreaus, Brazil), an MTA based sealer. We suggest that carefully selected cases can give a higher success rate and this method should be considered as one of the treatment modalities. PMID:25298723

  2. Endodontic implants

    PubMed Central

    Yadav, Rakesh K.; Tikku, A. P.; Chandra, Anil; Wadhwani, K. K.; Ashutosh kr; Singh, Mayank

    2014-01-01

    Endodontic implants were introduced back in 1960. Endodontic implants enjoyed few successes and many failures. Various reasons for failures include improper case selection, improper use of materials and sealers and poor preparation for implants. Proper case selection had given remarkable long-term success. Two different cases are being presented here, which have been treated successfully with endodontic implants and mineral trioxide aggregate Fillapex (Andreaus, Brazil), an MTA based sealer. We suggest that carefully selected cases can give a higher success rate and this method should be considered as one of the treatment modalities. PMID:25298723

  3. MINIMALLY INVASIVE ANTEROLATERAL ACCESS ROUTE FOR TOTAL HIP ARTHROPLASTY

    PubMed Central

    Sawaia, Rogério Naim; Galvão, Antonio Felipe Martensen; Oliveira, Fernando Machado; Secunho, Guilherme Rondinelli; Filho, Geraldo Vilela

    2015-01-01

    Objective: The aim of this study was to present a minimally invasive anterolateral access route and to ascertain whether this enables total hip replacement without compromising the quality of the implant positioning, while maintaining the integrity of the gluteus muscles. Method: A retrospective study was conducted on 260 patients (186 females and 74 males) with an average age of 62 years. There were 18 bilateral cases, totaling 278 hips. All the patients had osteoarthritis and had undergone non-cemented total hip arthroplasty (metal-metal or metal-polyethylene) between October 2004 and December 2007. A minimally invasive anterolateral access route was used, measuring 7 to 10 cm in length, according to body weight and the size of the femoral head. The patients were assessed clinically regarding age, sex and presence of the Trendelenburg sign, and radiologically regarding acetabular and femoral positioning. Results: The acetabular inclination was between 30° and 40° in 78 patients, between 41° and 50° in 189 patients, and 51° or over in 11 patients. On anteroposterior radiographs to study femoral positioning, the positioning was central in 209 cases, 41 presented valgus deviation and 28 presented varus deviation. On lateral views, 173 were central, 67 anterior and 38 posterior. The mean duration of the procedure was 63 minutes. Regarding complications, there were five cases of infection, three of deep vein thrombosis, two of hip dislocation, 80 of lengthening of the lower limbs and five of shortening of the operated limb. The Trendelenburg sign was present in four cases, of which one showed superior gluteal nerve injury. Conclusion: The minimally invasive anterolateral access route made it possible to perform total hip arthroplasty without compromising the positioning of the implants, thereby maintaining the integrity of the gluteus muscles.

  4. Mechanical testing and modelling of the Universal 2 implant.

    PubMed

    Gislason, M K; Foster, E; Main, D; Fusiek, G; Niewczas, P; Bransby-Zachary, M; Nash, D H

    2016-06-01

    Understanding the load mechanics of orthopaedic implants is important to be able to predict their behaviour in-vivo. Much research, both mechanical and clinical, has been carried out on hip and knee implants, but less has been written about the mechanics of wrist implants. In this paper, the load mechanics of the Universal 2 wrist implant have been measured using two types of measuring techniques, strain gauges and Fibre Bragg Grating measurements to measure strains. The results were compared to a finite element model of the implant. The results showed that the computational results were in good agreement with the experimental results. Better understanding of the load mechanics of wrist implants, using models and experimental results can catalyse the development of future generation implants. PMID:27083120

  5. Stress shielding effects of two prosthetic groups after total hip joint simulation replacement

    PubMed Central

    2014-01-01

    Objective The study aims to compare the stress shielding effects of implantable anatomical and traditional prostheses after in vitro total hip joint replacement simulation. The study serves as a biomechanical basis for novel artificial prostheses and for clinical hip joint replacements. Methods Sixteen femoral specimens from adult male corpses were randomly divided into two groups: the traditional prosthesis group implanted into femur specimens using simulated total hip joint replacement (n = 8) and the femoral neck-preserved anatomical prosthesis implantation group that used a collum femoris preserving stem/trabeculae oriented pattern (CFP/TOP) acetabular cup (n = 8). The strain values in the two groups before and after prosthesis implantation were measured at different test points using electric resistance strain gauges. The stress shielding rate was calculated according to the related formula. Results The results showed that the rates of proximal femoral stress shielding were significantly higher at test points 1–10 in the traditional femoral prosthesis transplantation group than in the anatomical prosthesis group (p < 0.05). Conclusions There were different effects of stress shielding between the anatomical and traditional prostheses. Retained femoral anatomical implants should reduce stress shielding and increase the stability of anatomical prosthesis implants. PMID:25174846

  6. Surface and Subsurface Analyses of Metal-on-Polyethylene Total Hip Replacement Retrievals.

    PubMed

    Vuong, Vicky; Pettersson, Maria; Persson, Cecilia; Larsson, Sune; Grandfield, Kathryn; Engqvist, Håkan

    2016-05-01

    Metal-on-polyethylene (MoP) articulations are one of the most reliable implanted hip prostheses. Unfortunately, long-term failure remains an obstacle to the service life. There is a lack of higher resolution research investigating the metallic surface component of MoP hip implants. This study investigates the surface and subsurface features of metallic cobalt chromium molybdenum alloy (CoCrMo) femoral head components from failed MoP retrievals. Unused prostheses were used for comparison to differentiate between wear-induced defects and imperfections incurred during implant manufacturing. The predominant scratch morphology observed on the non-implanted references was shallow and linear, whereas the scratches on the retrievals consisted of largely nonlinear, irregular scratches of varying depth (up to 150 nm in retrievals and up to 60 nm in reference samples). Characteristic hard phases were observed on the surface and subsurface material of the cast samples. Across all samples, a 100-400 nm thick nanocrystalline layer was visible in the immediate subsurface microstructure. Although observation of the nanocrystalline layer has been reported in metal-on-metal articulations, its presence in MoP retrievals and unimplanted prostheses has not been extensively examined. The results suggest that manufacturing-induced surface and subsurface microstructural features are present in MoP hip prostheses prior to implantation and naturally, these imperfections may influence the in vivo wear processes after implantation. PMID:26399989

  7. Trunnionosis in total hip arthroplasty: a review.

    PubMed

    Mistry, Jaydev B; Chughtai, Morad; Elmallah, Randa K; Diedrich, Aloise; Le, Sidney; Thomas, Melbin; Mont, Michael A

    2016-03-01

    Trunnionosis is defined as wear of the femoral head-neck interface and has recently been acknowledged as a growing cause of total hip arthroplasty failure. Some studies have reported that it accounts for up to 3 % of all revisions. The exact cause of trunnionosis is currently unknown; however, postulated etiologies include modular junction wear, corrosion damage, and metal ion release. Additionally, implant design and trunnion geometries may contribute to the progression of component failure. In order to aid in our understanding of this phenomenon, our aim was to present the current literature on (1) the effect of femoral head size on trunnionosis, (2) the effect of trunnion design on trunnionosis, (3) localized biological reactions associated with trunnionosis, and (4) gross trunnion failures. It is hoped that this will encourage further research and interest aimed at minimizing this complication. PMID:26868420

  8. Graphitic Tribological Layers in Metal-on-Metal Hip Replacements

    NASA Astrophysics Data System (ADS)

    Liao, Y.; Pourzal, R.; Wimmer, M. A.; Jacobs, J. J.; Fischer, A.; Marks, L. D.

    2011-12-01

    Arthritis is a leading cause of disability, and when nonoperative methods have failed, a prosthetic implant is a cost-effective and clinically successful treatment. Metal-on-metal replacements are an attractive implant technology, a lower-wear alternative to metal-on-polyethylene devices. Relatively little is known about how sliding occurs in these implants, except that proteins play a critical role and that there is a tribological layer on the metal surface. We report evidence for graphitic material in the tribological layer in metal-on-metal hip replacements retrieved from patients. As graphite is a solid lubricant, its presence helps to explain why these components exhibit low wear and suggests methods of improving their performance; simultaneously, this raises the issue of the physiological effects of graphitic wear debris.

  9. [Prostate-rectum spacers: optimization of prostate cancer irradiation].

    PubMed

    Zilli, T; Benz, E; Miralbell, R

    2014-06-01

    In the curative radiotherapy of localized prostate cancer, improvements in biochemical control observed with dose escalation have been counterbalanced by an increase in radiation-induced toxicity. The injection of biodegradable spacers between prostate and rectum represents a new frontier in the optimization of radiotherapy treatments for patients with localized disease. Transperineal injection of different types of spacers under transrectal ultrasound guidance allows creating a 7-to-20 mm additional space between the prostate and the anterior rectal wall lasting 3 to 12 months. Dosimetrically, a relative reduction in the rectal volume receiving at least 70 Gy (V70) in the order of 43% to 84% is observed with all types of spacers, regardless of the radiotherapy technique used. Preliminary clinical results show for all spacers a good tolerance and a possible reduction in the acute side effects rate. The aim of the present systematic review of the literature is to report on indications as well as dosimetric and clinical advantages of the different types of prostate-rectum spacers commercially available (hydrogel, hyaluronic acid, collagen, biodegradable balloon). PMID:24746454

  10. Conservation of sequence in recombination signal sequence spacers.

    PubMed Central

    Ramsden, D A; Baetz, K; Wu, G E

    1994-01-01

    The variable domains of immunoglobulins and T cell receptors are assembled through the somatic, site specific recombination of multiple germline segments (V, D, and J segments) or V(D)J rearrangement. The recombination signal sequence (RSS) is necessary and sufficient for cell type specific targeting of the V(D)J rearrangement machinery to these germline segments. Previously, the RSS has been described as possessing both a conserved heptamer and a conserved nonamer motif. The heptamer and nonamer motifs are separated by a 'spacer' that was not thought to possess significant sequence conservation, however the length of the spacer could be either 12 +/- 1 bp or 23 +/- 1 bp long. In this report we have assembled and analyzed an extensive data base of published RSS. We have derived, through extensive consensus comparison, a more detailed description of the RSS than has previously been reported. Our analysis indicates that RSS spacers possess significant conservation of sequence, and that the conserved sequence in 12 bp spacers is similar to the conserved sequence in the first half of 23 bp spacers. PMID:8208601

  11. Evaluation of a new spacer device for drug inhalation.

    PubMed

    Stenius-Aarniala, B; Kiviranta, K; Poppius, H

    1993-01-01

    We have studied the efficacy and acceptability of a new inhalation spacer device. The functional principle of the device, differing from that of conventional spacers, is based on evaporation of the propellant during circular movement of the aerosol in a small spherical chamber. We assessed the bronchodilating effect of salbutamol (Salbuvent) inhaled with the new spacer (Rondo) compared with salbutamol (Ventoline) inhaled with the spacer Volumatic and with salbutamol (Salbuvent) inhaled with a conventional metered dose actuator using a double-blind cross-over arrangement. Fifteen asthmatic patients were treated over a period of 4 weeks. They used each of the three different devices for 2-3 days every week. Peak expiratory flow rates were recorded every morning after one and after two puffs of the study drugs. The bronchodilator responses to the three treatments were similar within narrow ranges of estimate. By visual analogue scale assessment the new spacer was significantly easier to handle (P < 0.05) and more convenient to carry around (P < 0.01) than Volumatic. PMID:8453959

  12. Impact of spacer thickness on biofouling in forward osmosis.

    PubMed

    Valladares Linares, R; Bucs, Sz S; Li, Z; AbuGhdeeb, M; Amy, G; Vrouwenvelder, J S

    2014-06-15

    Forward osmosis (FO) indirect desalination systems integrate wastewater recovery with seawater desalination. Niche applications for FO systems have been reported recently, due to the demonstrated advantages compared to conventional high-pressure membrane processes such as nanofiltration (NF) and reverse osmosis (RO). Among them, wastewater recovery has been identified to be particularly suitable for practical applications. However, biofouling in FO membranes has rarely been studied in applications involving wastewater effluents. Feed spacers separating the membrane sheets in cross-flow systems play an important role in biofilm formation. The objective of this study was to determine the influence of feed spacer thickness (28, 31 and 46 mil) on biofouling development and membrane performance in a FO system, using identical cross-flow cells in parallel studies. Flux development, biomass accumulation, fouling localization and composition were determined and analyzed. For all spacer thicknesses, operated at the same feed flow and the same run time, the same amount of biomass was found, while the flux reduction decreased with thicker spacers. These observations are in good agreement with biofouling studies for RO systems, considering the key differences between FO and RO. Our findings contradict previous cross-flow studies on particulate/colloidal fouling, where higher cross-flow velocities improved system performance. Thicker spacers reduced the impact of biofouling on FO membrane flux. PMID:24726992

  13. Pathogenic organisms in hip joint infections

    PubMed Central

    Geipel, Udo

    2009-01-01

    Infections of the hip joint are usually of bacterial etiology. Only rarely, an infectious arthritis is caused in this localization by viruses or fungi. Native joint infections of the hip are less common than infections after implantation of prosthetic devices. Difficulties in prosthetic joint infections are, (I) a higher age of patients, and, thus an associated presence of other medical risk factors, (II) often long courses of treatment regimes depending on the bacterium and its antibiotic resistance, (III) an increased mortality, and (IV) a high economic burden for removal and reimplantation of an infected prosthetic device. The pathogenic mechanisms responsible for articular infections are well studied only for some bacteria, e.g. Staphylococcus aureus, while others are only partially understood. Important known bacterial properties and microbiological characteristics of infection are the bacterial adhesion on the native joint or prosthetic material, the bacterial biofilm formation, the development of small colony variants (SCV) as sessile bacterial types and the increasing resistance to antibiotics. PMID:19834588

  14. Metal-on-metal hip joint tribology.

    PubMed

    Dowson, D; Jin, Z M

    2006-02-01

    The basic tribological features of metal-on-metal total hip replacements have been reviewed to facilitate an understanding of the engineering science underpinning the renaissance of these hard-on-hard joints. Metal-on-polymer hip replacements operate in the boundary lubrication regime, thus leading to the design guidance to reduce the femoral head diameter as much as is feasible to minimize frictional torque and volumetric wear. This explains why the gold-standard implant of this form from the past half-century had a diameter of only 22.225 mm (7/8 in). Metal-on-metal implants can operate in the mild mixed lubrication regime in which much of the applied load is supported by elastohydrodynamic films. Correct tribological design leads to remarkably low steady state wear rates. Promotion of the most effective elastohydrodynamic films calls for the largest possible head diameters and the smallest clearances that can reasonably be adopted, consistent with fine surface finishes, good sphericity and minimal structural elastic deformation of the cup on its foundations. This guidance, which is opposite in form to that developed for metal-on-polymer joints, is equally valid for solid (monolithic) metallic heads on metallic femoral stems and surface replacement femoral shells. Laboratory measurements of friction and wear in metal-on-metal joints have confirmed their potential to achieve a very mild form of mixed lubrication. The key lies in the generation of effective elastohydrodynamic lubricating films of adequate thickness compared with the composite roughness of the head and cup. The calculation of the film thickness is by no means easy, but the full procedure is outlined and the use of an empirical formula that displays good agreement with calculations based upon the full numerical solutions is explained. The representation of the lambda ratio, lambda, embracing both film thickness and composite roughness, is described. PMID:16669380

  15. Review of quality of x-rays for templating for total hip arthroplasty.

    PubMed

    Khan, Faiz; Ahmad, Tayyab; Condon, Finbarr; Lenehan, Brian

    2015-03-01

    Digital templating of x-rays for total hip arthroplasty is used routinely for pre-operative planning. This is to assure that appropriately sized implants are selected to replicate patient's hip biomechanics. Multiple studies have shown that templating does not always correspond to the final implants used. The aim of this study was to assess the suitability of the x-rays taken pre-operatively for templating for total hip arthroplasty. We undertook a review of a series of pre-operative templating pelvis x-rays in 100 consecutive patients undergoing total hip arthroplasty. These x-rays were compared against set criteria to determine their suitability for use for templating. We determined that six x-rays met the criteria whereas ninety four x-rays did not meet the criteria for suitable x-rays. Twenty patients had repeat x-rays. The reasons for unsuitability were inadequate opposite femur (66%), absence or incomplete template (54%), inadequate femur length (47%), external rotation (39%), absence of opposite hip (4%). The twenty repeated x-rays were also reviewed for the same parameters and two (10%) satisfied the established criteria. It is imperative that x-rays for templating for total hip arthroplasty are done to a strict standard to obtain an x-ray that is appropriate for templating and there is minimal exposure of the patient to irradiation. PMID:26280858

  16. Hip biomechanics in orthopaedic clinical practice.

    PubMed

    Antolic, Vane; Kralj-Iglic, Veronika; Iglic, Ales; Pompe, Borut

    2002-01-01

    Radiographic and clinical studies, coupled with biomechanical assessment of the hip, are important tools for predicting the development of osteoarthitis of the hip. In order to better understand the treatment of hip dysplasia, it is necessary to determine the contact stress in the hip joint. In this study, a three-dimensional mathematical model was used to determine hip joint contact stress. Because of the discrepancy in the results of analyses of different radiographic indicators of hip dysplasia, the calculation of hip joint contact stress is proposed for a more accurate assessment of the severity of hip dysplasia. PMID:12097976

  17. Cochlear Implants

    MedlinePlus

    ... such as those provided by lipreading or sign language. How does someone receive a cochlear implant? Use of a cochlear implant requires both a surgical procedure and significant therapy to learn or relearn the sense of hearing. Not everyone performs at the same ...

  18. A novel sensor concept for optimization of loosening diagnostics in total hip replacement.

    PubMed

    Ruther, Cathérine; Ewald, Hartmut; Mittelmeier, Wolfram; Fritsche, Andreas; Bader, Rainer; Kluess, Daniel

    2011-10-01

    The main reason for the revision of total hip replacements is aseptic loosening, caused by stress shielding and wear particle induced osteolysis. In order to detect an implant loosening early, the osseointegration of endoprosthetic implants must be measured exactly. Currently applied diagnostic methods, such as standard radiographs and clinical symptomatology, often result in an imprecise diagnosis. A novel radiation-free method to improve the diagnostic investigation of implant loosening is presented. The osseointegration of an implant can be identified using mechanical magnetic sensors (oscillators), which impinge on small membranes inside an implant component, e.g., the femoral hip stem. The maximum velocity after impingement of the oscillator depends on the osseointegration of the implant. Excitation of the oscillator is realized by a coil outside the human body. Another external coil is used to detect the velocity of the oscillator. To demonstrate the principle of the novel loosening sensor, an overdimensioned test device was designed to measure simulated loosening phases in the first experimental tests with different material layers. The overdimensioned test device of the loosening sensor showed significant differences in the various phases of fixation. Analysis of the membrane without any material layer in the case of advanced loosening resulted in a 23% higher maximum velocity compared to an attached artificial bone layer. Based on these preliminary results, the sensor system shows potential for the detection of implant loosening. Moreover, the proposed system could be used in experimental applications to determine the quality of bioactive coatings and new implant materials. PMID:22070337

  19. Metal-on-Metal Total Hip Resurfacing Arthroplasty

    PubMed Central

    2006-01-01

    Executive Summary Objective The objective of this review was to assess the safety and effectiveness of metal on metal (MOM) hip resurfacing arthroplasty for young patients compared with that of total hip replacement (THR) in the same population. Clinical Need Total hip replacement has proved to be very effective for late middle-aged and elderly patients with severe degenerative diseases of the hips. As indications for THR began to include younger patients and those with a more active life style, the longevity of the implant became a concern. Evidence suggests that these patients experience relatively higher rates of early implant failure and the need for revision. The Swedish hip registry, for example, has demonstrated a survival rate in excess of 80% at 20 years for those aged over 65 years, whereas this figure was 33% by 16 years in those aged under 55 years. Hip resurfacing arthroplasty is a bone-conserving alternative to THR that restores normal joint biomechanics and load transfer. The technique has been used around the world for more than 10 years, specifically in the United Kingdom and other European countries. The Technology Metal-on-metal hip resurfacing arthroplasty is an alternative procedure to conventional THR in younger patients. Hip resurfacing arthroplasty is less invasive than THR and addresses the problem of preserving femoral bone stock at the initial operation. This means that future hip revisions are possible with THR if the initial MOM arthroplasty becomes less effective with time in these younger patients. The procedure involves the removal and replacement of the surface of the femoral head with a hollow metal hemisphere, which fits into a metal acetabular cup. Hip resurfacing arthroplasty is a technically more demanding procedure than is conventional THR. In hip resurfacing, the femoral head is retained, which makes it much more difficult to access the acetabular cup. However, hip resurfacing arthroplasty has several advantages over a conventional THR with a small (28 mm) ball. First, the large femoral head reduces the chance of dislocation, so that rates of dislocation are less than those with conventional THR. Second, the range of motion with hip resurfacing arthroplasty is higher than that achieved with conventional THR. A variety of MOM hip resurfacing implants are used in clinical practice. Six MOM hip resurfacing implants have been issued licences in Canada. Review Strategy A search of electronic bibliographies (OVID Medline, Medline In-Process and Other Non-Indexed Citations, Embase, Cochrane CENTRAL and DSR, INAHTA) was undertaken to identify evidence published from Jan 1, 1997 to October 27, 2005. The search was limited to English-language articles and human studies. The literature search yielded 245 citations. Of these, 11 met inclusion criteria (9 for effectiveness, 2 for safety). The result of the only reported randomized controlled trial on MOM hip resurfacing arthroplasty could not be included in this assessment, because it used a cemented acetabular component, whereas in the new generation of implants, a cementless acetabular component is used. After omitting this publication, only case series remained. Summary of Findings   Health Outcomes The Harris hip score and SF-12 are 2 measures commonly used to report health outcomes in MOM hip resurfacing arthroplasty studies. Other scales used are the Oxford hip score and the University of California Los Angeles hip score. The case series showed that the mean revision rate of MOM hip resurfacing arthroplasty is 1.5% and the incidence of femoral neck fracture is 0.67%. Across all studies, 2 cases of osteonecrosis were reported. Four studies reported improvement in Harris hip scores. However, only 1 study reported a statistically significant improvement. Three studies reported improvement in SF-12 scores, of which 2 reported a significant improvement. One study reported significant improvement in UCLA hip score. Two studies reported postoperative Oxford hip scores, but no preoperative values were reported. None of the reviewed studies reported procedure-related deaths. Four studies reported implant survival rates ranging from 94.4% to 99.7% for a follow-up period of 2.8 to 3.5 years. Three studies reported on the range of motion. One reported improvement in all motions including flexion, extension, abduction-adduction, and rotation, and another reported improvement in flexion. Yet another reported improvement in range of motion for flexion abduction-adduction and rotation arc. However, the author reported a decrease in the range of motion in the arc of flexion in patients with Brooker class III or IV heterotopic bone (all patients were men). Safety of Metal-on-Metal Hip Resurfacing Arthroplasty There is a concern about metal wear debris and its systemic distribution throughout the body. Detectable metal concentrations in the serum and urine of patients with metal hip implants have been described as early as the 1970s, and this issue is still controversial after 35 years. Several studies have reported high concentration of cobalt and chromium in serum and/or urine of the patients with metal hip implants. Potential toxicological effects of the elevated metal ions have heightened concerns about safety of MOM bearings. This is of particular concern in young and active patients in whom life expectancy after implantation is long. Since 1997, 15 studies, including 1 randomized clinical trial, have reported high levels of metal ions after THR with metal implants. Some of these studies have reported higher metal levels in patients with loose implants. Adverse Biological Effects of Cobalt and Chromium Because patients who receive a MOM hip arthroplasty are shown to be exposed to high concentrations of metallic ions, the Medical Advisory Secretariat searched the literature for reports of adverse biological effects of cobalt and chromium. Cobalt and chromium make up the major part of the metal articulations; therefore, they are a focus of concern. Risk of Cancer To date, only one study has examined the incidence of cancer after MOM and polyethylene on metal total hip arthroplasties. The results were compared to that of general population in Finland. The mean duration of follow-up for MOM arthroplasty was 15.7 years; for polyethylene arthroplasty, it was 12.5 years. The standardized incidence ratio for all cancers in the MOM group was 0.95 (95% CI, 0.79–1.13). In the polyethylene on metal group it was 0.76 (95% CI, 0.68–0.86). The combined standardized incidence ratio for lymphoma and leukemia in the patients who had MOM THR was 1.59 (95% CI, 0.82–2.77). It was 0.59 (95% CI, 0.29–1.05) for the patients who had polyethylene on metal THR. Patients with MOM THR had a significantly higher risk of leukemia. All patients who had leukemia were aged over than 60 years. Cobalt Cardiotoxicity   Epidemiological Studies of Myocardiopathy of Beer Drinkers An unusual type of myocardiopathy, characterized by pericardial effusion, elevated hemoglobin concentrations, and congestive heart failure, occurred as an epidemic affecting 48 habitual beer drinkers in Quebec City between 1965 and 1966. This epidemic was directly related the consumption of a popular beer containing cobalt sulfate. The epidemic appeared 1 month after cobalt sulfate was added to the specific brewery, and no further cases were seen a month after this specific chemical was no longer used in making this beer. A beer of the same name is made in Montreal, and the only difference at that time was that the Quebec brand of beer contained about 10 times more cobalt sulphate. Cobalt has been added to some Canadian beers since 1965 to improve the stability of the foam but it has been added in larger breweries only to draught beer. However, in small breweries, such as those in Quebec City, separate batches were not brewed for bottle and draught beer; therefore, cobalt was added to all of the beer processed in this brewery. In March 1966, a committee was appointed under the chairmanship of the Deputy Minister of Health for Quebec that included members of the department of forensic medicine of Quebec’s Ministry of Justice, epidemiologists, members of Food and Drug Directorate of Ottawa, toxicologists, biomedical researchers, pathologists, and members of provincial police. Epidemiological studies were carried out by the Provincial Ministry of Health and the Quebec City Health Department. The association between the development of myocardiopathy and the consumption of the particular brand of beer was proven. The mortality rate of this epidemic was 46.1% and those who survived were desperately ill, and recovered only after a struggle for their lives. Similar cases were seen in Omaha (Nebraska). The epidemic started after a cobalt additive was used in 1 of the beers marketed in Nebraska. Sixty-four patients with the clinical diagnosis of alcoholic myocardiopathy were seen during an 18-month period (1964–1965). Thirty of these patients died. The first patient became ill within 1 month after cobalt was added to the beer, and the last patient was seen within 1 month of withdrawal of cobalt. A similar epidemic occurred in Minneapolis, Minnesota. Between 1964 and 1967, 42 patients with acute heart failure were admitted to a hospital in Minneapolis, Minnesota. Twenty of these patients were drinking 6 to 30 bottles per day of a particular brand of beer exclusively. The other 14 patients also drank the same brand of beer, but not exclusively. The mortality rate from the acute illness was 18%, but late deaths accounted for a total mortality rate of 43%. Examination of the tissue from these patients revealed markedly abnormal changes in myofibrils (heart muscles), mitochondria, and sarcoplasmic reticulum. In Belgium, a similar epidemic was reported in 1966, in which, cobalt was used in some Belgian beers. There was a difference in mortality between the Canadian or American epidemic and this series. Only 1 of 24 patients died, 1.5 years after the diagnosis. In March 1965, at an international meeting in Brussels, a new heart disease in chronic beer drinkers was described. This disease consists of massive pericardial effusion, low cardiac output, raised venous pressure, and polycythemia in some cases. This syndrome was thought to be different from the 2 other forms of alcoholic heart disease (beriberi and a form characterized by myocardial fibrosis). The mystery of the above epidemics as stated by investigators is that the amount of cobalt added to the beer was below the therapeutic doses used for anemia. For example, 24 pints of Quebec brand of beer in Quebec would contain 8 mg of cobalt chloride, whereas an intake of 50 to 100 mg of cobalt as an antianemic agent has been well tolerated. Thus, greater cobalt intake alone does not explain the occurrence of myocardiopathy. It seems that there are individual differences in cobalt toxicity. Other features, like subclinical alcoholic heart disease, deficient diet, and electrolyte imbalance could have been precipitating factors that made these patients susceptible to cobalt’s toxic effects. In the Omaha epidemic, 60% of the patients had weight loss, anorexia, and occasional vomiting and diarrhea 2 to 6 months before the onset of cardiac symptoms. In the Quebec epidemic, patients lost their appetite 3 to 6 months before the diagnosis of myocardiopathy and developed nausea in the weeks before hospital admission. In the Belgium epidemic, anorexia was one of the most predominant symptoms at the time of diagnosis, and the quality and quantity of food intake was poor. Alcohol has been shown to increase the uptake of intracoronary injected cobalt by 47%. When cobalt enters the cells, calcium exits; this shifts the cobalt to calcium ratio. The increased uptake of cobalt in alcoholic patients may explain the high incidence of cardiomyopathies in beer drinkers’ epidemics. As all of the above suggest, it may be that prior chronic exposure to alcohol and/or a nutritionally deficient diet may have a marked synergistic effect with the cardiotoxicity of cobalt. Conclusions MOM hip resurfacing arthroplasty has been shown to be an effective arthroplasty procedure as tested in younger patients. However, evidence for effectiveness is based only on 7 case series with short duration of follow-up (2.8–3.5 years). There are no RCTs or other well-controlled studies that compare MOM hip resurfacing with THR. Revision rates reported in the MOM studies using implants currently licensed in Canada (hybrid systems, uncemented acetabular, and cemented femoral) range from 0.3% to 3.6% for a mean follow-up ranging from 2.8 to 3.5 years. Fracture of femoral neck is not very common; it occurs in 0.4% to 2.2% of cases (as observed in a short follow-up period). All the studies that measured health outcomes have reported improvement in Harris Hip and SF-12 scores; 1 study reported significant reduction in pain and improvement in function, and 2 studies reported significant improvement in SF-12 scores. One study reported significant improvement in UCLA Hip scores. Concerns remain on the potential adverse effects of metal ions. Longer-term follow-up data will help to resolve the inconsistency of findings on adverse effects, including toxicity and carcinogenicity. Ontario-Based Economic Analysis The device cost for MOM ranges from $4,300 to $6,000 (Cdn). Traditional hip replacement devices cost about $2,000 (Cdn). Using Ontario Case Costing Initiative data, the total estimated costs for hip resurfacing surgery including physician fees, device fees, follow-up consultation, and postsurgery rehabilitation is about $15,000 (Cdn). Figure 1: Cost of Total Hip Replacement Surgery in Ontario Hip Resurfacing Surgery (Based on 2005/06 inflationary-adjusted rates) Weighted Average (Academic Community! al-inclusive hospitalization cost of surgery $ 6.767.18 Device Cost $ 5,400.00 Additional Medication $ 330.75 Follow-up Consultation $ 190.30 Rehab (per outpatient CCAC case) $ 1,500.00 OH P costs (average) $ 1,068.60 Total Estimated Cost $ 15,256.83 MOM hip arthroplasty is generally recommended for patients aged under 55 years because its bone-conserving advantage enables patients to “buy time” and hence helps THRs to last over the lifetime of the patient. In 2004/2005, 15.9% of patients who received THRs were aged 55 years and younger. It is estimated that there are from 600 to 1,000 annual MOM hip arthroplasty surgeries in Canada with an estimated 100 to 150 surgeries in Ontario. Given the increased public awareness of this device, it is forecasted that demand for MOM hip arthroplasty will steadily increase with a conservative estimate of demand rising to 1,400 cases by 2010 (Figure 10). The net budget impact over a 5-year period could be $500,000 to $4.7 million, mainly because of the increasing cost of the device. Figure 2: Projected Number of Metal-on-Metal Hip Arthroplasty Surgeries in Ontario: to 2010 PMID:23074495

  20. Impaction bone grafting and cemented stem revision in periprosthetic hip fractures: a novel surgical technique.

    PubMed

    Dearden, Paul M; Bobak, Peter P; Giannoudis, Peter V

    2014-01-01

    With an ageing population, and increasing longevity of hip arthroplasty prostheses, the incidence of periprosthetic femoral fractures is rising. We present a simple and easily reproducible technique for reduction of any periprosthetic fracture that requires bone graft augmentation. This method facilitates impaction bone grafting to reconstitute lost bone stock and revision using a cemented implant. PMID:24186679

  1. Contact mechanics and wear simulations of hip resurfacing devices using computational methods.

    PubMed

    Ali, Murat; Mao, Ken

    2014-01-01

    The development of computational and numerical methods provides the option to study the contact mechanics and wear of hip resurfacing devices. The importance of these techniques is justified by the extensive amount of testing and experimental work required to verify and improve current orthopaedic implant devices. As the demands for device longevity is increasing, it is as important as ever to study techniques for providing much needed orthopaedic hip implant solutions. Through the use of advanced computer aided design and the finite element method, contact analysis of hip resurfacing devices was carried out by developing both three-dimensional and two-dimensional axisymmetric models whilst considering the effects of loading conditions and material properties on the contact stresses. Following on from this, the three-dimensional model was used in combination with a unique programme to develop wear simulations and obtain cumulative wear for both the acetabular cup and femoral head simultaneously. PMID:25087775

  2. Isolated fracture of the hip stem prosthesis made of austenitic steel - a literature review.

    PubMed

    Mierzejewska, Żaneta Anna; Oksiut, Zbigniew

    2014-01-01

    Proper design and functioning of the hip joint ensure smooth motion over the full range in multiple planes. Any change in this arrangement may lead to joint damage, causing deformation, pain and loss of functionality. Hip replacement is a procedure intended to replace the damaged articular surfaces and replacing them with artificial components. However, as any surgical intervention, it carries the risk of serious complications. One of them are isolated stem fractures, consisting of breaking the implant inside the intramedullary canal without damaging the surrounding tissue. This article contains a review of the literature data concerning the clinical cases of isolated fractures of hip endoprosthesis stems made of austenitic stainless steel. Although stem fractures are one of the rarest complications of implantation, the lack of clear description of the causes of this phenomenon in the literature makes it worthwhile to take up on the subject. PMID:25133797

  3. Wheeze in childhood: is the spacer good enough?

    PubMed Central

    Rajkumar, Veena; Rajendra, Barathi; How, Choon How; Ang, Seng Bin

    2014-01-01

    Max was treated with SABA using an MDI and spacer with facemask and responded well to the initial treatment. You explained to the parents that nebulisers are neither required nor recommended in the treatment of wheezing in their child’s situation. You advised the parents on the proper technique of MDI use with spacer and facemask, as well as care of the equipment. You also gave them a clearly written action plan regarding the efficient management of the next episode of wheeze with MDI and spacer. You further explained the side effects of oral bronchodilators and nebulisers, and why you refrained from using them. Max was given a follow-up appointment to assess his progress, and his parents were advised on the situations when they should go to a doctor or the emergency department. PMID:25631964

  4. A study of CD budget in spacer patterning technology

    NASA Astrophysics Data System (ADS)

    Mukai, Hidefumi; Shiobara, Eishi; Takahashi, Shinya; Hashimoto, Kohji

    2008-03-01

    We constructed CD budget for spacer patterning technology which is one of the strongest candidates in double patterning technologies for below 3x nm half pitch generations. In the CD budgeting, three patterning portions of grid patterns should be considered, namely, "line", "paired space" and "adjoined space", because they have individual process error sources that affect CD variations. Analysis of the patterning process flow revealed that the amount of CD variations for positive type spacer patterning technology was in the order of "adjoined space" > "paired space" > "line". Also, the experimental verifications in CD variations substantiated the constructed CD budget. From the viewpoint of design for manufacturability (DfM), these process features should be taken into account in the device engineering. Therefore, for the successful implementation of spacer patterning technology into high-end devices, we propose a cross- functional development scheme encompassing device technologies and process technologies using the constructed CD budget.

  5. RAPID MANUFACTURING SYSTEM OF ORTHOPEDIC IMPLANTS.

    PubMed

    Relvas, Carlos; Reis, Joana; Potes, José Alberto Caeiro; Fonseca, Fernando Manuel Ferreira; Simões, José Antonio Oliveira

    2009-01-01

    This study, aimed the development of a methodology for rapid manufacture of orthopedic implants simultaneously with the surgical intervention, considering two potential applications in the fields of orthopedics: the manufacture of anatomically adapted implants and implants for bone loss replacement. This work innovation consists on the capitation of the in situ geometry of the implant by direct capture of the shape using an elastomeric material (polyvinylsiloxane) which allows fine detail and great accuracy of the geometry. After scanning the elastomeric specimen, the implant is obtained by machining using a CNC milling machine programmed with a dedicated CAD/CAM system. After sterilization, the implant is able to be placed on the patient. The concept was developed using low cost technology and commercially available. The system has been tested in an in vivo hip arthroplasty performed on a sheep. The time increase of surgery was 80 minutes being 40 minutes the time of implant manufacturing. The system developed has been tested and the goals defined of the study achieved enabling the rapid manufacture of an implant in a time period compatible with the surgery time. PMID:27004181

  6. RAPID MANUFACTURING SYSTEM OF ORTHOPEDIC IMPLANTS

    PubMed Central

    Relvas, Carlos; Reis, Joana; Potes, José Alberto Caeiro; Fonseca, Fernando Manuel Ferreira; Simões, José Antonio Oliveira

    2015-01-01

    This study, aimed the development of a methodology for rapid manufacture of orthopedic implants simultaneously with the surgical intervention, considering two potential applications in the fields of orthopedics: the manufacture of anatomically adapted implants and implants for bone loss replacement. This work innovation consists on the capitation of the in situ geometry of the implant by direct capture of the shape using an elastomeric material (polyvinylsiloxane) which allows fine detail and great accuracy of the geometry. After scanning the elastomeric specimen, the implant is obtained by machining using a CNC milling machine programmed with a dedicated CAD/CAM system. After sterilization, the implant is able to be placed on the patient. The concept was developed using low cost technology and commercially available. The system has been tested in an in vivo hip arthroplasty performed on a sheep. The time increase of surgery was 80 minutes being 40 minutes the time of implant manufacturing. The system developed has been tested and the goals defined of the study achieved enabling the rapid manufacture of an implant in a time period compatible with the surgery time. PMID:27004181

  7. Spacer effect on nanostructures and self-assembly in organogels via some bolaform cholesteryl imide derivatives with different spacers

    PubMed Central

    2013-01-01

    In this paper, new bolaform cholesteryl imide derivatives with different spacers were designed and synthesized. Their gelation behaviors in 23 solvents were investigated, and some of them were found to be low molecular mass organic gelators. The experimental results indicated that these as-formed organogels can be regulated by changing the flexible/rigid segments in spacers and organic solvents. Suitable combination of flexible/rigid segments in molecular spacers in the present cholesteryl gelators is favorable for the gelation of organic solvents. Scanning electron microscopy and atomic force microscopy observations revealed that the gelator molecules self-assemble into different aggregates, from wrinkle and belt to fiber with the change of spacers and solvents. Spectral studies indicated that there existed different H-bond formations between imide groups and assembly modes, depending on the substituent spacers in molecular skeletons. The present work may give some insight into the design and character of new organogelators and soft materials with special molecular structures. PMID:24083361

  8. Hip-Hop Education Resources

    ERIC Educational Resources Information Center

    Hall, Marcella Runell

    2009-01-01

    Hip-hop music and culture are often cited as being public pedagogy, meaning the music itself has intrinsic educational value. Non-profit organizations and individual educators have graciously taken the lead in utilizing hip-hop to educate. As the academy continues to debate its effectiveness, teachers and community organizers are moving forward.…

  9. Hip-Hop Education Resources

    ERIC Educational Resources Information Center

    Hall, Marcella Runell

    2009-01-01

    Hip-hop music and culture are often cited as being public pedagogy, meaning the music itself has intrinsic educational value. Non-profit organizations and individual educators have graciously taken the lead in utilizing hip-hop to educate. As the academy continues to debate its effectiveness, teachers and community organizers are moving forward.

  10. The impact of proximal femoral morphology on failure strength with a mid-head resection short-stem hip arthroplasty.

    PubMed

    Olsen, Michael; Al Saied, Mohamed; Morison, Zachary; Sellan, Michael; Waddell, James P; Schemitsch, Emil H

    2014-12-01

    Mid-head resection short-stem hip arthroplasty is a conservative alternative to conventional total hip replacement and addresses proximal fixation challenges in patients not suitable for hip resurfacing. It is unclear whether proximal femoral morphology impacts the ultimate failure load of mid-head resection implanted femurs, thus the aim of this study was to investigate the effect of native neck-shaft angle (NSA) and coronal implant alignment on proximal femoral strength. In total, 36 synthetic femurs with two different proximal femoral morphologies were utilized in this study. Of them, 18 femurs with a varus NSA of 120° and 18 femurs with a valgus NSA of 135° were each implanted with a mid-head resection prosthesis. Femurs within the two different femoral morphology groups were divided into three equal coronal implant alignment groups: 10° valgus, 10° varus or neutral alignment. Prepared femurs were tested for stiffness and to failure in axial compression. There was no significant difference in stiffness nor failure load between femurs implanted with valgus-, varus- or neutrally aligned implants in femurs with a NSA of 120° (p = 0.396, p = 0.111, respectively). Femurs implanted in valgus orientation were significantly stiffer and failed at significantly higher loads than those implanted in varus alignment in femurs with a NSA of 135° (p = 0.001, p = 0.007, respectively). A mid-head resection short-stem hip arthroplasty seems less sensitive to clinically relevant variations of coronal implant alignment and may be more forgiving upon implantation in some femoral morphologies, however, a relative valgus component alignment is recommended. PMID:25515228

  11. Lower end fitting debris collector and end cap spacer grid

    SciTech Connect

    Bryan, W.J.

    1990-04-24

    This patent describes a nuclear reactor having fuel assemblies including an upper end fitting and spaced nuclear fuel rod spacer grids for supporting and spacing a plurality of elongated nuclear fuel rods. Each includes a hollow active portion of nuclear fuel filled cladding intermediate the rod ends and tapering end cap of solid material with a circumferential groove on the rod end which first encounters reactor coolant flow, a lower end filtering debris collector and end cap spacer grid for capturing and retaining deleterious debris carried by reactor coolant before it enters the active region of a fuel assembly and creates fuel rod cladding damage.

  12. A retrospective analysis of bilateral fractures over sixteen years: localisation and variation in treatment of second hip fractures.

    PubMed

    Kok, Laura M; van der Steenhoven, Tim J; Nelissen, Rob G H H

    2011-10-01

    The aim of this study was the evaluation of contralateral hip fractures after a previous hip fracture. For this retrospective analysis patients were selected from the database of the LUMC, a teaching hospital in the south-west of the Netherlands. We analyzed all patients with a second fracture of a hip between 1992 and 2007. The exclusion criteria were high impact trauma and patients with diseases or medication known to have a negative effect on bone metabolism. A total of 1,604 hip fractures were identified. The possible predictive factors for the second fracture and descriptive statistics related to surgery (Hb and HT before and after the operation, total amount of intra- and postoperative blood loss, type of osteosynthesis, complications, time of death after the last fracture, time between arrival in the hospital and operation and hospital stay for both fractures) were recorded. A total of 32 second hip fractures were identified (2%) at a mean of 27.5 (SD 28.9) months after the initial hip fracture. The mean age at the first fracture was 77.2 years (SD 11.7), and 27 of 32 patients were female. Of these 32 patients (64 bilateral hip fractures), 32 fractures were intracapsular (1 femoral neck, 31 subcapital) and 32 were extracapsular fractures (6 subtrochanteric, 26 transtrochanteric). Although 24 of the 32 patients had identical first and second hip fractures, only eight out of 32 hips were treated with the same implants. There was a significant difference in Singh index between both hips at the time of the first fracture. There was also a significant difference in Singh index between the hip which was not fractured compared with its subsequent index when it was broken. All other studied patient and fracture characteristics were not significantly different. In this population the percentage of second hip fractures was relatively low compared to other studies. The choice of implants in this study shows that implants were chosen randomly. Because there is a significant difference in the Singh index during first and second hip fracture, osteoporosis medication might help reduce the incidence of second hip fractures. PMID:21165617

  13. Primary hip replacement prostheses and their evidence base: systematic review of literature

    PubMed Central

    Kynaston-Pearson, F; Ashmore, A M; Malak, T T; Rombach, I; Taylor, A; Beard, D; Arden, N K; Price, A; Prieto-Alhambra, D; Judge, A; Carr, A J

    2013-01-01

    Objective To determine the extent to which prostheses with no readily available evidence to support their use are being implanted in primary total hip arthroplasty. Design Systematic review of the literature. Data sources The 9th annual report of the National Joint Registry of England and Wales (NJR) was analysed to identify prostheses with an Orthopaedic Data Evaluation Panel rating of “unclassified” or “pre-entry” used in primary total hip arthroplasty in 2011. A systematic review of those prostheses was carried out using PubMed, Cochrane, Embase, OVID, and Google databases. Study selection Prostheses used in primary total hip arthroplasty as published in the NJR’s 9th annual report were analysed. Only literature that included the name of the prosthesis was included. Literature yielded in the search results was excluded if it reported animal, non-orthopaedic, non-total hip arthroplasty, or non-device related studies. Results The systematic review found that 24% (57/235) of all hip replacement implants available to surgeons in the UK have no evidence for their clinical effectiveness. It also shows that 10 617 (7.8%) of the 136 593 components used in primary hip replacements in 2011 were implanted without readily identifiable evidence of clinical effectiveness. These comprised 157 cemented stems (0.5% of 34 655 implanted), 936 (2.8% of 33 367) uncemented stems, 1732 (7.1% of 24 349) cemented cups, and 7577 (17.1% of 44 222) uncemented cups. Conclusions This study shows that a considerable proportion of prostheses available to orthopaedic surgeons have no readily available evidence of clinical effectiveness to support their use. Concern exists about the current system of device regulation, and the need for a revised process for introducing new orthopaedic devices is highlighted. PMID:24355538

  14. Cup Position Alone Does Not Predict Risk of Dislocation after Hip Arthroplasty

    PubMed Central

    Esposito, Christina I.; Gladnick, Brian P.; Lee, Yuo-yu; Lyman, Stephen; Wright, Timothy M.; Mayman, David J.; Padgett, Douglas E.

    2014-01-01

    Recent studies suggest the ‘Lewinnek safe zone’ for acetabular component position is outdated. We used a large prospective institutional registry to determine if there is a ‘safe zone’ exists for acetabular component position within which the risk of hip dislocation is low and if other patient and implant factors affect the risk of hip dislocation. Patients who reported a dislocation event within six months after hip replacement surgery were identified, and acetabular component position was measured with anteroposterior radiographs. The frequency of dislocation was 2.1% (147 of 7040 patients). No significant difference was found in the number of dislocated hips among the zones. Dislocators <50 years old were less active preoperatively than nondislocators (p=0.006). Acetabular component position alone is not protective against instability. PMID:25249516

  15. Long-term outcome of a metal-on-polyethylene cementless hip resurfacing.

    PubMed

    Tan, Timothy L; Ebramzadeh, Edward; Campbell, Patricia A; Al-Hamad, Mariam; Amstutz, Harlan C

    2014-04-01

    Due to the well-documented problems surrounding metal-on-metal bearings, the use of hip resurfacing has declined. Since the potential benefits of hip resurfacing remain desirable, it may be beneficial to investigate the long-term outcome of hip resurfacings using metal-on-polyethylene in the 1980's. We report the long-term survivorship and modes of failure of a cementless metal-on-polyethylene resurfacing (n = 178) with different porous ingrowth surfaces. While acetabular loosening was absent, a high incidence of femoral failures (femoral loosening = 18.1%, osteolytic neck fracture = 21%) occurred despite using the same ingrowth surface for both components. Ongoing developments using the lessons learned from these previous generation components and utilizing modern low wear materials, e.g., cross-linked polyethylene, may lead to improved implants for future hip resurfacings. PMID:24090660

  16. Cochlear implants.

    PubMed

    Macherey, Olivier; Carlyon, Robert P

    2014-09-22

    Cochlear implants are the first example of a neural prosthesis that can substitute a sensory organ: they bypass the malfunctioning auditory periphery of profoundly-deaf people to electrically stimulate their auditory nerve. The history of cochlear implants dates back to 1957, when Djourno and Eyriès managed, for the first time, to elicit sound sensations in a deaf listener using an electrode implanted in his inner ear. Since then, considerable technological and scientific advances have been made. Worldwide, more than 300,000 deaf people have been fitted with a cochlear implant; it has become a standard clinical procedure for born-deaf children and its success has led over the years to relaxed patient selection criteria; for example, it is now not uncommon to see people with significant residual hearing undergoing implantation. Although the ability to make sense of sounds varies widely among the implanted population, many cochlear implant listeners can use the telephone and follow auditory-only conversations in quiet environments. PMID:25247367

  17. CoCrMo metal-on-metal hip replacements.

    PubMed

    Liao, Yifeng; Hoffman, Emily; Wimmer, Markus; Fischer, Alfons; Jacobs, Joshua; Marks, Laurence

    2013-01-21

    After the rapid growth in the use of CoCrMo metal-on-metal hip replacements since the second generation was introduced circa 1990, metal-on-metal hip replacements have experienced a sharp decline in the last two years due to biocompatibility issues related to wear and corrosion products. Despite some excellent clinical results, the release of wear and corrosion debris and the adverse response of local tissues have been of great concern. There are many unknowns regarding how CoCrMo metal bearings interact with the human body. This perspective article is intended to outline some recent progresses in understanding wear and corrosion of metal-on-metal hip replacement both in vivo and in vitro. The materials, mechanical deformation, corrosion, wear-assisted corrosion, and wear products will be discussed. Possible adverse health effects caused by wear products will be briefly addressed, as well as some of the many open questions such as the detailed chemistry of corrosion, tribochemical reactions and the formation of graphitic layers. Nowadays we design almost routinely for high performance materials and lubricants for automobiles; humans are at least as important. It is worth remembering that a hip implant is often the difference between walking and leading a relatively normal life, and a wheelchair. PMID:23196425

  18. CoCrMo Metal-on-Metal Hip Replacements

    PubMed Central

    Liao, Yifeng; Hoffman, Emily; Wimmer, Markus; Fischer, Alfons; Jacobs, Joshua; Marks, Laurence

    2012-01-01

    After the rapid growth in the use of CoCrMo metal-on-metal hip replacements since the second generation was introduced circa 1990, metal-on-metal hip replacements have experienced a sharp decline in the last two years due to biocompatibility issues related to wear and corrosion products. Despite some excellent clinical results, the release of wear and corrosion debris and the adverse response of local tissues have been of great concern. There are many unknowns regarding how CoCrMo metal bearings interact with the human body. This perspective article is intended to outline some recent progresses in understanding wear and corrosion of metal-on-metal hip replacement both in-vivo and in-vitro. The materials, mechanical deformation, corrosion, wear-assisted corrosion, and wear products will be discussed. Possible adverse health effects caused by wear products will be briefly addressed, as well as some of the many open questions such as the detailed chemistry of corrosion, tribochemical reactions and the formation of graphitic layers. Nowadays we design almost routinely for high performance materials and lubricants for automobiles; humans are at least as important. It is worth remembering that a hip implant is often the difference between walking and leading a relatively normal life, and a wheelchair. PMID:23196425

  19. Hip Abduction Can Prevent Posterior Edge Loading of Hip Replacements

    PubMed Central

    van Arkel, Richard J; Modenese, Luca; Phillips, Andrew TM; Jeffers, Jonathan RT

    2013-01-01

    Edge loading causes clinical problems for hard-on-hard hip replacements, and edge loading wear scars are present on the majority of retrieved components. We asked the question: are the lines of action of hip joint muscles such that edge loading can occur in a well-designed, well-positioned acetabular cup? A musculoskeletal model, based on cadaveric lower limb geometry, was used to calculate for each muscle, in every position within the complete range of motion, whether its contraction would safely pull the femoral head into the cup or contribute to edge loading. The results show that all the muscles that insert into the distal femur, patella, or tibia could cause edge loading of a well-positioned cup when the hip is in deep flexion. Patients frequently use distally inserting muscles for movements requiring deep hip flexion, such as sit-to-stand. Importantly, the results, which are supported by in vivo data and clinical findings, also show that risk of edge loading is dramatically reduced by combining deep hip flexion with hip abduction. Patients, including those with sub-optimally positioned cups, may be able to reduce the prevalence of edge loading by rising from chairs or stooping with the hip abducted. © 2013 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 31:1172–1179, 2013. PMID:23575923

  20. Transparency to Reduce Surgical Implant Waste

    PubMed Central

    Dilisio, Matthew F.; Patti, Brianna; Fening, Stephen D.; Junko, Jeffrey T.

    2015-01-01

    Background Rising health care costs and emphasis on value have placed the onus of reducing healthcare costs on the surgeon. Methods Financial data from 3,973 hip, knee, and shoulder arthroplasties performed at a physician owned orthopedic hospital was retrospectively reviewed over a two-year period. A wasted implant financial report was posted starting the second year of the study. Each surgeon's performance could be identified by his peers. Results After posting of the financial report, 1.11% of all hip and knee arthroplasty cases had a waste event compared to 1.50% during the control year. Shoulder arthroplasty waste events occurred twice as often than that observed in hip and knee arthroplasty during the study period. A decrease in waste events was observed but was not statistically significant (p = 0.30). Conclusions Posting a non-blinded wasted implant data sheet was associated with a reduction in the number of wasted orthopedic surgical implants in this series, although the reduction was not statistically significant. PMID:26217467

  1. Total Hip Arthroplasty Using the S-ROM-A Prosthesis for Anatomically Difficult Asian Patients

    PubMed Central

    Hozumi, Akira; Kobayashi, Kyousuke; Tsuru, Nobuhisa; Miyamoto, Chikara; Maeda, Jyunichiro; Chiba, Ko; Goto, Hisataka; Osaki, Makoto

    2015-01-01

    Background. The S-ROM-A prosthesis has been designed for the Asian proximal femur with a small deformed shape and narrow canal. In this study, the clinical and radiological results using the S-ROM-A prosthesis for Japanese patients with severe deformity due to dysplasia and excessive posterior pelvic tilt were examined. Methods. 94 hips were followed up for a mean of 55 months, with a mean age at surgery of 61 years. The primary diagnoses were 94 coxarthritis cases, including 51 dysplasia and 37 primary OA, 1 avascular necrosis, 2 traumatic arthritis, and 3 Perthes disease. Thirty-one hips had been treated with osteotomy of the hip joints. Preoperative intramedullary canal shapes were stovepipe in 23 hips, normal in 51 hips, and champagne-flute in 5 hips. The maximum pelvic inclination angle was 56°. Results. The mean JOA score improved from 46 points preoperatively to 80 points at final follow-up. On radiological evaluation of the fixation of the implants according to the Engh classification, 92 (97%) hips were classified as “bone ingrown fixation.” Conclusion. In primary THA, using the S-ROM-A prosthesis for Asian patients with proximal femoral deformity, even after osteotomy and with posterior pelvic tilt, provided good short- to midterm results. PMID:26582575

  2. The tradeoffs associated with modular hip prostheses.

    PubMed

    Collier, J P; Mayor, M B; Williams, I R; Surprenant, V A; Surprenant, H P; Currier, B H

    1995-02-01

    In an effort to gain greater insight into the tradeoffs associated with modular hip prostheses, 2 approaches were taken. A questionnaire was sent to each of the orthopaedic implant manufacturing companies asking specific questions regarding modular components, and a series of retrieved prostheses, both modular and nonmodular, were examined to determine the potential sources of problems associated with modular connections. The respondents to the questionnaire generally agreed that it was more expensive to produce modular prostheses due to the required tolerances at the modular connections, and that the increased flexibility provided by the modularity was important to surgical outcome. There was less consensus on whether inventories were reduced and little data to support any improvement in surgical outcome caused by modularity. The most frequent problems associated with modular connections were fretting and corrosion. Easily observable significant fretting occurred in 4% of 701 head/neck tapers. Corrosion was observed in > 30% of the mixed-alloy head/stem combinations, in < 10% of all-titanium-alloy modular components, and in < 6% of all-cobalt-alloy devices. In 1 series of retrieved modular femoral components (15 titanium alloy and 15 cobalt alloy) with both sets having approximately the same duration of implantation, 7% of the all-cobalt-alloy components had corrosion, whereas 33% of the mixed-alloy components had corrosion. PMID:7634596

  3. [Sport activity after hip and knee arthroplasty].

    PubMed

    Keren, Amit; Berkovich, Yaron; Berkovitch, Yaron; Soudry, Michael

    2013-11-01

    Joint arthroplasty is one of the commonest surgical procedures in orthopedic surgery. In recent years there was an increase in the number of procedures, patient satisfaction and implant survival. Originally, these operations were designed for old patients in order to relieve pain and to enable ambulation. Over the past few years, these operations have become common in younger patients which desire to return to activity, including sports activities. The importance of physical activity is a well known fact. In recent years it became clear that with the proper physical activity the outcomes of the operations are better. There are several types of arthroplasty. Many factors influence the outcome of the operation apart from the post-surgery physical activity. These factors include patient factors, surgical technique and type of arthroplasty. This review summarizes the recommendations for sports activities after hip and knee arthroplasties. These activities are evaluated according to surgeons' recommendations, stress applied on the implant and long term outcomes. The recommended sports activities after joint arthroplasties are walking, swimming and cycling. Soccer, basketball and jogging are not advised. Tennis, downhill skiing and horse riding are recommended with previous experience. There are many more sports activities that patients can participate in, and it is important that the patient discuss the different options prior to the operation. Since these operations are so common, many non-orthopedic physicians encounter these patients in their practice. They should be acquainted with the recommendations for sports activities and encourage them. PMID:24416822

  4. Psoas muscle pyogenic abscess in association with infected hip arthroplasty: a rare case of simultaneous bilateral presentation.

    PubMed

    Volpin, Andrea; Kini, Sunil Gurpur; Berizzi, Antonio

    2015-01-01

    Simultaneous bilateral presentation of psoas abscess with prosthetic joint involvement is extremely rare. A 68-year-old woman presented to us with bilateral dull aching groin pain of 6?months' duration, which flared up in the past month, associated with pyrexial symptoms. She had undergone bilateral hip replacements in the past with uneventful recovery. MRI showed bilateral psoas muscle collection in communication with the hip joints. Preoperative hip aspirate demonstrated frank pus with positivity on Gram stain and radiographs confirmed prosthetic loosening of bilateral hips. The patient subsequently underwent two-stage revision arthroplasty of both infected hip implants. At 5-year follow-up, the patient remains asymptomatic with good functional outcome and no recurrence on serial MRI. PMID:25994433

  5. Fabricating specialised orthopaedic implants using additive manufacturing

    NASA Astrophysics Data System (ADS)

    Unwin, Paul

    2014-03-01

    It has been hypothesised that AM is ideal for patient specific orthopaedic implants such as those used in bone cancer treatment, that can rapidly build structures such as lattices for bone and tissues to in-grow, that would be impossible using current conventional subtractive manufacturing techniques. The aim of this study was to describe the adoption of AM (direct metal laser sintering and electron beam melting) into the design manufacturing and post-manufacturing processes and the early clinical use. Prior to the clinical use of AM implants, extensive metallurgical and mechanical testing of both laser and electron beam fabrications were undertaken. Concurrently, post-manufacturing processes evaluated included hipping, cleaning and coating treatments. The first clinical application of a titanium alloy mega-implant was undertaken in November 2010. A 3D model of the pelvic wing implant was designed from CT scans. Novel key features included extensive lattice structures at the bone interfaces and integral flanges to fix the implant to the bone. The pelvic device was implanted with the aid of navigation and to date the patient remains active. A further 18 patient specific mega-implants have now been implanted. The early use of this advanced manufacturing route for patient specific implants has been very encouraging enabling the engineer to produce more advanced and anatomical conforming implants. However, there are a new set of design, manufacturing and regulatory challenges that require addressing to permit this technique to be used more widely. This technology is changing the design and manufacturing paradigm for the fabrication of specialised orthopaedic implants.

  6. 21 CFR 888.3400 - Hip joint femoral (hemi-hip) metallic resurfacing prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Hip joint femoral (hemi-hip) metallic resurfacing... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3400 Hip joint femoral (hemi-hip) metallic resurfacing prosthesis. (a) Identification. A hip joint femoral...

  7. 21 CFR 888.3400 - Hip joint femoral (hemi-hip) metallic resurfacing prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint femoral (hemi-hip) metallic resurfacing... HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Prosthetic Devices § 888.3400 Hip joint femoral (hemi-hip) metallic resurfacing prosthesis. (a) Identification. A hip joint femoral...

  8. Computer-integrated revision total hip replacement surgery: concept and preliminary results.

    PubMed

    Taylor, R H; Joskowicz, L; Williamson, B; Guéziec, A; Kalvin, A; Kazanzides, P; Van Vorhis, R; Yao, J; Kumar, R; Bzostek, A; Sahay, A; Börner, M; Lahmer, A

    1999-09-01

    This paper describes an ongoing project to develop a computer-integrated system to assist surgeons in revision total hip replacement (RTHR) surgery. In RTHR surgery, a failing orthopedic hip implant, typically cemented, is replaced with a new one by removing the old implant, removing the cement and fitting a new implant into an enlarged canal broached in the femur. RTHR surgery is a difficult procedure fraught with technical challenges and a high incidence of complications. The goals of the computer-based system are the significant reduction of cement removal labor and time, the elimination of cortical wall penetration and femur fracture, the improved positioning and fit of the new implant resulting from precise, high-quality canal milling and the reduction of bone sacrificed to fit the new implant. Our starting points are the ROBODOC system for primary hip replacement surgery and the manual RTHR surgical protocol. We first discuss the main difficulties of computer-integrated RTHR surgery and identify key issues and possible solutions. We then describe possible system architectures and protocols for preoperative planning and intraoperative execution. We present a summary of methods and preliminary results in CT image metal artifact removal, interactive cement cut-volume definition and cement machining, anatomy-based registration using fluoroscopic X-ray images and clinical trials using an extended RTHR version of ROBODOC. We conclude with a summary of lessons learned and a discussion of current and future work. PMID:10710298

  9. Breast Implants

    MedlinePlus

    ... are two types of breast implants approved for sale in the United States: saline-filled and silicone ... Radiation-Emitting Products Vaccines, Blood & Biologics Animal & Veterinary Cosmetics Tobacco Products

  10. Cochlear Implants

    MedlinePlus

    ... to the clinic for checkups; and whether your insurance company pays for the procedure. Cost of implants More ... cost as much as $100,000. Fortunately, most insurance companies and Medicare provide benefits that cover the cost. ...

  11. Cochlear Implants

    MedlinePlus

    ... a chest pocket. The speech processor is a computer that analyzes and digitizes the sound signals and ... additional visits are needed for activating, adjusting, and programming the various electrodes that have been implanted. Also, ...

  12. Modular hybrid total hip arthroplasty. Experimental study in dogs

    PubMed Central

    2011-01-01

    Background This prospective experimental study evaluated the surgical procedure and results of modular hybrid total hip arthroplasty in dogs. Methods Ten skeletally mature healthy mongrel dogs with weights varying between 19 and 27 kg were used. Cemented modular femoral stems and uncemented porous-coated acetabular cups were employed. Clinical and radiographic evaluations were performed before surgery and at 30, 60, 90, 120, 180 and 360 days post-operation. Results Excellent weight bearing was noticed in the operated limb in seven dogs. Dislocation followed by loosening of the prosthesis was noticed in two dogs, which were therefore properly treated with a femoral head osteotomy. Femoral fracture occurred in one dog, which was promptly treated with full implant removal and femoral osteosynthesis. Conclusions The canine modular hybrid total hip arthroplasty provided excellent functionality of the operated limb. PMID:21736758

  13. CRISPR interference and priming varies with individual spacer sequences

    PubMed Central

    Xue, Chaoyou; Seetharam, Arun S.; Musharova, Olga; Severinov, Konstantin; J. Brouns, Stan J.; Severin, Andrew J.; Sashital, Dipali G.

    2015-01-01

    CRISPR–Cas (clustered regularly interspaced short palindromic repeats-CRISPR associated) systems allow bacteria to adapt to infection by acquiring ‘spacer’ sequences from invader DNA into genomic CRISPR loci. Cas proteins use RNAs derived from these loci to target cognate sequences for destruction through CRISPR interference. Mutations in the protospacer adjacent motif (PAM) and seed regions block interference but promote rapid ‘primed’ adaptation. Here, we use multiple spacer sequences to reexamine the PAM and seed sequence requirements for interference and priming in the Escherichia coli Type I-E CRISPR–Cas system. Surprisingly, CRISPR interference is far more tolerant of mutations in the seed and the PAM than previously reported, and this mutational tolerance, as well as priming activity, is highly dependent on spacer sequence. We identify a large number of functional PAMs that can promote interference, priming or both activities, depending on the associated spacer sequence. Functional PAMs are preferentially acquired during unprimed ‘naïve’ adaptation, leading to a rapid priming response following infection. Our results provide numerous insights into the importance of both spacer and target sequences for interference and priming, and reveal that priming is a major pathway for adaptation during initial infection. PMID:26586800

  14. Arthroscopic Treatment of Traumatic Hip Dislocation.

    PubMed

    Begly, John P; Robins, Bryan; Youm, Thomas

    2016-05-01

    Traumatic hip dislocations are high-energy injuries that often result in considerable morbidity. Although appropriate management improves outcomes, associated hip pathology may complicate the recovery and lead to future disability and pain. Historically, open reduction has been the standard of care for treating hip dislocations that require surgical intervention. The use of hip arthroscopy to treat the sequelae and symptoms resulting from traumatic hip dislocations recently has increased, however. When used appropriately, hip arthroscopy is a safe, effective, and minimally invasive treatment option for intra-articular pathology secondary to traumatic hip dislocation. PMID:27007728

  15. A Novel Murine Model of Established Staphylococcal Bone Infection in the Presence of a Fracture Fixation Plate to Study Therapies Utilizing Antibiotic-laden Spacers after Revision Surgery

    PubMed Central

    Inzana, Jason A.; Schwarz, Edward M.; Kates, Stephen L.; Awad, Hani A.

    2014-01-01

    Mice are the small animal model of choice in biomedical research due to the low cost and availability of genetically engineered lines. However, the devices utilized in current mouse models of implant-associated bone infection have been limited to intramedullary or trans-cortical pins, which are not amenable to treatments involving extensive debridement of a full-thickness bone loss and placement of a segmental antibiotic spacer. To overcome these limitations, we developed a clinically faithful model that utilizes a locking fracture fixation plate to enable debridement of an infected segmental bone defect (full-thickness osteotomy) during a revision surgery, and investigated the therapeutic effects of placing an antibiotic-laden spacer in the segmental bone defect. To first determine the ideal time point for revision following infection, a 0.7 mm osteotomy in the femoral mid-shaft was stabilized with a radiolucent PEEK fixation plate. The defect was inoculated with bioluminescent Staphylococcus aureus, and the infection was monitored over 14 days by bioluminescent imaging (BLI). Osteolysis and reactive bone formation were assessed by X-ray and micro-computed tomography (micro-CT). The active bacterial infection peaked by 5 days post-inoculation, however the stability of the implant fixation became compromised by 10–14 days post-inoculation due to osteolysis around the screws. Thus, day 7 was defined as the ideal time point to perform the revision surgery. During the revision surgery, the infected tissue was debrided and the osteotomy was widened to 3 mm to place a poly-methyl methacrylate spacer, with or without vancomycin. Half of the groups also received systemic vancomycin for the remaining 21 days of the study. The viable bacteria remaining at the end of the study were measured using colony forming unit assays. Volumetric bone changes (osteolysis and reactive bone formation) were directly measured using micro-CT image analysis. Mice that were treated with local or systemic vancomycin did not display gross pathology at the end of the study. While localized vancomycin delivery alone tended to decrease the bacterial burden and osteolysis, these effects were only significant when combined with systemic antibiotic therapy. This novel mouse model replicates key features of implant-associated osteomyelitis that make treatment extremely difficult, such as biofilm formation and osteolysis, and imitates the clinical practice of placing an antibiotic-laden spacer after infected tissue debridement. In addition, the model demonstrates the limitations of current PMMA spacers and could be an invaluable tool for evaluating alternative antimicrobial treatments for implant-associated bone infection. PMID:25459073

  16. Impingement and dislocation in total hip arthroplasty: mechanisms and consequences.

    PubMed

    Brown, Thomas D; Elkins, Jacob M; Pedersen, Douglas R; Callaghan, John J

    2014-01-01

    In contemporary total hip arthroplasty, instability has been a complication in approximately 2% to 5% of primary surgeries and 5% to 10% of revisions. Due to the reduction in the incidence of wear-induced osteolysis that has been achieved over the last decade, instability now stands as the single most common reason for revision surgery. Moreover, even without frank dislocation, impingement and subluxation are implicated in a set of new concerns arising with advanced bearings, associated with the relatively unforgiving nature of many of those designs. Against that backdrop, the biomechanical factors responsible for impingement, subluxation, and dislocation remain under-investigated relative to their burden of morbidity. This manuscript outlines a 15-year program of laboratory and clinical research undertaken to improve the scientific basis for understanding total hip impingement and dislocation. The broad theme has been to systematically evaluate the role of surgical factors, implant design factors, and patient factors in predisposing total hip constructs to impinge, sublux, and/or dislocate. Because this class of adverse biomechanical events had not lent itself well to study with existing approaches, it was necessary to develop (and validate) a series of new research methodologies, relying heavily on advanced finite element formulations. Specific areas of focus have included identifying the biomechanical challenges posed by dislocation-prone patient activities, quantifying design parameter effects and component surgical positioning effects for conventional metal-on-polyethylene implant constructs, and the impingement/dislocation behavior of non-conventional constructs, quantifying the stabilizing role of the hip capsule (and of surgical repairs of capsule defects), and systematically studying impingement and edge loading of hard-on-hard bearings, fracture of ceramic liners, confounding effects of patient obesity, and subluxation-mediated worsening of third body particle challenge. PMID:25328453

  17. Performance Analysis and Test on the KAERI Devised Spacer Grids for PWRs

    NASA Astrophysics Data System (ADS)

    Song, Kee-Nam; Lee, Soo-Bum

    Spacer grid which is one of the most important structural components in a pressurized light water reactor fuel assembly supports the fuel rods laterally and vertically. Based on design experiences and by scrutinizing the design features of advanced nuclear fuels and the international patents of spacer grids, KAERI has devised its own spacer grid shapes and acquired patents. In this study, a performance evaluation on two new spacer grid shapes devised by KAERI was carried out from mechanical/structural and thermohydraulic view points. And also a performance evaluation on two commercial spacer grid shapes was carried out for the sake of a comparison. The comparisons included the spring characteristics, fuel rod vibration characteristics, fretting wear resistance, impact strength characteristics, CHF enhancement, and pressure drop level of the spacer grid shapes. The comparison results have shown that the performances of the new spacer grid shapes are better or at least not worse than those of the commercial spacer grid shapes.

  18. Future Bearing Surfaces in Total Hip Arthroplasty

    PubMed Central

    2014-01-01

    One of the most important issues in the modern total hip arthroplasty (THA) is the bearing surface. Extensive research on bearing surfaces is being conducted to seek an ideal bearing surface for THA. The ideal bearing surface for THA should have superior wear characteristics and should be durable, bio-inert, cost-effective, and easy to implant. However, bearing surfaces that are currently being implemented do not completely fulfill these requirements, especially for young individuals for whom implant longevity is paramount. Even though various new bearing surfaces have been investigated, research is still ongoing, and only short-term results have been reported from clinical trials. Future bearing surfaces can be developed in the following ways: (1) change in design, (2) further improvement of polyethylene, (3) surface modification of the metal, (4) improvement in the ceramic, and (5) use of alternative, new materials. One way to reduce wear and impingement in THA is to make changes in its design by using a large femoral head, a monobloc metal shell with preassembled ceramic liner, dual mobility cups, a combination of different bearing surfaces, etc. Polyethylene has improved over time with the development of highly crosslinked polyethylene. Further improvements can be made by reinforcing it with vitamin E or multiwalled carbon nanotubes and by performing a surface modification with a biomembrane. Surface modifications with titanium nitride or titanium niobium nitride are implemented to try to improve the metal bearings. The advance to the fourth generation ceramics has shown relatively promising results, even in young patients. Nevertheless, further improvement is required to reduce fragility and squeaking. Alternative materials like diamond coatings on surfaces, carbon based composite materials, oxidized zirconium, silicon nitride, and sapphire are being sought. However, long-term studies are necessary to confirm the efficacy of these surfaces after enhancements have been made with regard to fixation technique and implant quality. PMID:24605198

  19. Future bearing surfaces in total hip arthroplasty.

    PubMed

    Chang, Jun-Dong

    2014-03-01

    One of the most important issues in the modern total hip arthroplasty (THA) is the bearing surface. Extensive research on bearing surfaces is being conducted to seek an ideal bearing surface for THA. The ideal bearing surface for THA should have superior wear characteristics and should be durable, bio-inert, cost-effective, and easy to implant. However, bearing surfaces that are currently being implemented do not completely fulfill these requirements, especially for young individuals for whom implant longevity is paramount. Even though various new bearing surfaces have been investigated, research is still ongoing, and only short-term results have been reported from clinical trials. Future bearing surfaces can be developed in the following ways: (1) change in design, (2) further improvement of polyethylene, (3) surface modification of the metal, (4) improvement in the ceramic, and (5) use of alternative, new materials. One way to reduce wear and impingement in THA is to make changes in its design by using a large femoral head, a monobloc metal shell with preassembled ceramic liner, dual mobility cups, a combination of different bearing surfaces, etc. Polyethylene has improved over time with the development of highly crosslinked polyethylene. Further improvements can be made by reinforcing it with vitamin E or multiwalled carbon nanotubes and by performing a surface modification with a biomembrane. Surface modifications with titanium nitride or titanium niobium nitride are implemented to try to improve the metal bearings. The advance to the fourth generation ceramics has shown relatively promising results, even in young patients. Nevertheless, further improvement is required to reduce fragility and squeaking. Alternative materials like diamond coatings on surfaces, carbon based composite materials, oxidized zirconium, silicon nitride, and sapphire are being sought. However, long-term studies are necessary to confirm the efficacy of these surfaces after enhancements have been made with regard to fixation technique and implant quality. PMID:24605198

  20. Large head metal-on-metal cementless total hip arthroplasty versus 28mm metal-on-polyethylene cementless total hip arthroplasty: design of a randomized controlled trial

    PubMed Central

    Zijlstra, Wierd P; Bos, Nanne; van Raaij, Jos JAM

    2008-01-01

    Background Osteoarthritis of the hip is successfully treated by total hip arthroplasty with metal-on-polyethylene articulation. Polyethylene wear debris can however lead to osteolysis, aseptic loosening and failure of the implant. Large head metal-on-metal total hip arthroplasty may overcome polyethylene wear induced prosthetic failure, but can increase systemic cobalt and chromium ion concentrations. The objective of this study is to compare two cementless total hip arthroplasties: a conventional 28 mm metal-on-polyethylene articulation and a large head metal-on-metal articulation. We hypothesize that the latter arthroplasties show less bone density loss and higher serum metal ion concentrations. We expect equal functional scores, greater range of motion, fewer dislocations, fewer periprosthetic radiolucencies and increased prosthetic survival with the metal-on-metal articulation. Methods A randomized controlled trial will be conducted. Patients to be included suffer from non-inflammatory degenerative joint disease of the hip, are aged between 18 and 80 and are admitted for primary cementless unilateral total hip arthroplasty. Patients in the metal-on-metal group will receive a cementless titanium alloy acetabular component with a cobalt-chromium liner and a cobalt-chromium femoral head varying from 38 to 60 mm. Patients in the metal-on-polyethylene group will receive a cementless titanium alloy acetabular component with a polyethylene liner and a 28 mm cobalt-chromium femoral head. We will assess acetabular bone mineral density by dual energy x-ray absorptiometry (DEXA), serum ion concentrations of cobalt, chromium and titanium, self reported functional status (Oxford hip score), physician reported functional status and range of motion (Harris hip score), number of dislocations and prosthetic survival. Measurements will take place preoperatively, perioperatively, and postoperatively (6 weeks, 1 year, 5 years and 10 years). Discussion Superior results of large head metal-on-metal total hip arthroplasty over conventional hip arthroplasty have been put forward by experts, case series and the industry, but to our knowledge there is no randomized controlled evidence. Conclusion This randomized controlled study has been designed to test whether large head metal-on-metal cementless total hip arthroplasty leads to less periprosthetic bone density loss and higher serum metal ion concentrations compared to 28 mm metal-on-polyethylene cementless total hip arthroplasty. Trial registration Netherlands Trial Registry NTR1399 PMID:18842151

  1. [Atraumatic hip pain in young adults].

    PubMed

    González Murillo, M; Turcu, V; De Nicolás Navas, M B; Yeguas Bermejo, A

    2016-01-01

    Hip pain in the young adult is a disabling pathophysiological process may be related to multiple etiologies. The process must be determined in order to make a diagnosis and follow-up treatment. The case is presented of a 29 year old woman with anemia, atraumatic hip pain on the right side, and a limp of one month onset. The differential diagnosis includes infectious, rheumatological, tumor, avascular necrosis of hip, hip impingement, hip dysplasia, osteoarthritis and other syndromes. PMID:25239887

  2. Association of hip pain with radiographic evidence of hip osteoarthritis: diagnostic test study

    PubMed Central

    Nevitt, Michael C; Niu, Jingbo; Clancy, Mary M; Lane, Nancy E; Link, Thomas M; Vlad, Steven; Tolstykh, Irina; Jungmann, Pia M.; Felson, David T; Guermazi, Ali

    2015-01-01

    Study question Is there concordance between hip pain and radiographic hip osteoarthritis? Methods In this diagnostic test study, pelvic radiographs were assessed for hip osteoarthritis in two cohorts: the Framingham Osteoarthritis Study (community of Framingham, Massachusetts) and the Osteoarthritis Initiative (a multicenter longitudinal cohort study of osteoarthritis in the United States). Using visual representation of the hip joint, participants reported whether they had hip pain on most days and the location of the pain: anterior, groin, lateral, buttocks, or low back. In the Framingham study, participants with hip pain were also examined for hip pain with internal rotation. The authors analysed the agreement between radiographic hip osteoarthritis and hip pain, and for those with hip pain suggestive of hip osteoarthritis they calculated the sensitivity, specificity, positive predictive value, and negative predictive value of radiographs as the diagnostic test. Study answer and limitations In the Framingham study (n=946), only 15.6% of hips in patients with frequent hip pain showed radiographic evidence of hip osteoarthritis, and 20.7% of hips with radiographic hip osteoarthritis were frequently painful. The sensitivity of radiographic hip osteoarthritis for hip pain localised to the groin was 36.7%, specificity 90.5%, positive predictive value 6.0%, and negative predictive value 98.9%. Results did not differ much for hip pain at other locations or for painful internal rotation. In the Osteoarthritis Initiative study (n=4366), only 9.1% of hips in patients with frequent pain showed radiographic hip osteoarthritis, and 23.8% of hips with radiographic hip osteoarthritis were frequently painful. The sensitivity of definite radiographic hip osteoarthritis for hip pain localised to the groin was 16.5%, specificity 94.0%, positive predictive value 7.1%, and negative predictive value 97.6%. Results also did not differ much for hip pain at other locations. What this study adds Hip pain was not present in many hips with radiographic osteoarthritis, and many hips with pain did not show radiographic hip osteoarthritis. Most older participants with a high suspicion for clinical hip osteoarthritis (groin or anterior pain and/or painful internal rotation) did not have radiographic hip osteoarthritis, suggesting that in many cases, hip osteoarthritis might be missed if diagnosticians relied solely on hip radiographs. Funding, competing interests, data sharing See the full paper on thebmj.com for funding. The authors have no competing interests. Additional data are available from bevochan@bu.edu. PMID:26631296

  3. Influence of Hip Joint Position on Muscle Activity during Prone Hip Extension with Knee Flexion

    PubMed Central

    Suehiro, Tadanobu; Mizutani, Masatoshi; Okamoto, Mitsuhisa; Ishida, Hiroshi; Kobara, Kenichi; Fujita, Daisuke; Osaka, Hiroshi; Takahashi, Hisashi; Watanabe, Susumu

    2014-01-01

    [Purpose] This study investigated the selective activation of the gluteus maximus during a prone hip extension with knee flexion exercise, with the hip joint in different positions. [Subjects] The subjects were 21 healthy, male volunteers. [Methods] Activities of the right gluteus maximus, right hamstrings, bilateral lumbar erector spinae, and bilateral lumbar multifidus were measured using surface electromyography during a prone hip extension with knee flexion exercise. Measurements were made with the hip joint in each of 3 positions: (1) a neutral hip joint position, (2) an abduction hip joint position, and (3) an abduction with external rotation hip joint position. [Results] Gluteus maximus activity was significantly higher when the hip was in the abduction with external rotation hip joint position than when it was in the neutral hip joint and abduction hip joint positions. Gluteus maximus activity was also significantly higher in the abduction hip joint position than in the neutral hip joint position. Hamstring activity was significantly lower when the hip was in the abduction with external rotation hip joint position than when it was in the neutral hip joint and abduction hip joint positions. [Conclusion] Abduction and external rotation of the hip during prone hip extension with knee flexion exercise selectively activates the gluteus maximus. PMID:25540492

  4. Hip Surgery Candidates: A Comparative Study of Hip Osteoarthritis and Prior Hip Fracture Patient Characteristics

    PubMed Central

    Marks, Ray

    2008-01-01

    Aim: To assess similarities and differences in patient-related characteristics before and after surgery for painful disabling hip osteoarthritis among elderly subgroups with and without a trauma history. Method: First, a cohort of 1000 hospitalized patients were assessed for trends in: perceived duration of the condition, pain intensity, functional performance ability, walking distance, body mass, and comorbidity characteristics among other factors. Then, the most salient of these patient-related characteristics were compared between 42 cases of hip osteoarthritis without a trauma history and 42 cases with a trauma history matched for age and gender, using medical records and standard data recording and analysis procedures. Results: Hip osteoarthritis cases with a prior hip fracture history had a longer duration of disability, and were more impaired functionally before surgery (p < 0.05) than those with no such history. They also had lower leg muscle strength and used more assistive devices. Conclusion: Patients undergoing hip replacement surgery for painful hip osteoarthritis who have a hip fracture history are likely to be more impaired and disabled than those with no such history. PMID:19478931

  5. Investigating stress shielding spanned by biomimetic polymer-composite vs. metallic hip stem: A computational study using mechano-biochemical model.

    PubMed

    Tavakkoli Avval, Pouria; Samiezadeh, Saeid; Klika, Václav; Bougherara, Habiba

    2015-01-01

    Periprosthetic bone loss in response to total hip arthroplasty is a serious complication compromising patient's life quality as it may cause the premature failure of the implant. Stress shielding as a result of an uneven load sharing between the hip implant and the bone is a key factor leading to bone density decrease. A number of composite hip implants have been designed so far to improve load sharing characteristics. However, they have rarely been investigated from the bone remodeling point of view to predict a long-term response. This is the first study that employed a mechano-biochemical model, which considers the coupling effect between mechanical loading and bone biochemistry, to investigate bone remodeling after composite hip implantation. In this study, periprosthetic bone remodeling in the presence of Carbon fiber polyamide 12 (CF/PA12), CoCrMo and Ti alloy implants was predicted and compared. Our findings revealed that the most significant periprosthetic bone loss in response to metallic implants occurs in Gruen zone 7 (-43% with CoCrMo; -35% with Ti) and 6 (-40% with CoCrMo; -29% with Ti), while zone 4 has the lowest bone density decrease with all three implants (-9%). Also, the results showed that in terms of bone remodeling, the composite hip implant is more advantageous over the metallic ones as it provides a more uniform density change across the bone and induces less stress shielding which consequently results in a lower post-operative bone loss (-9% with CF/PA12 implant compared to -27% and -21% with CoCrMo and Ti alloy implants, respectively). PMID:25460403

  6. Midline-Splitting Open Door Laminoplasty Using Hydroxyapatite Spacers : Comparison between Two Different Shaped Spacers

    PubMed Central

    Park, Jin Hoon

    2012-01-01

    Objective Although hydroxyapatite (HA) spacer has been used for laminoplasty, there have been no reports on factors associated with fusion and on the effects of HA shape. Methods During January 2004 and January 2010, 45 patients with compressive cervical myelopathy underwent midline-splitting open door laminoplasty with winged (33 cases) and wingless (12 cases) HAs by a single surgeon. Minimal and mean follow up times were 12 and 28.1 months, respectively. Japanese Orthopedic Association (JOA) score was used for clinical outcome measurement. Cervical X-rays were taken preoperatively, immediately post-operatively, and after 3, 6, and 12 months and computed tomography scans were performed preoperatively, immediately post-operatively and after 12 months. Cervical lordosis, canal dimension, fusion between lamina and HA, and affecting factors of fusion were analyzed. Results All surgeries were performed on 142 levels, 99 in the winged and 43 in the wingless HA groups. JOA scores of the winged group changed from 10.4±2.94 to 13.3±2.35 and scores of the wingless group changed from 10.8±2.87 to 13.8±3.05. There was no significant difference on lordotic and canal dimensional change between two groups. Post-operative 12 month fusion rate between lamina and HA was significantly lower in the winged group (18.2 vs. 48.8% p=0.001). Multivariate analysis showed that ossification of the posterior longitudinal ligament, male gender, and wingless type HA were significantly associated with fusion. Conclusion Clinical outcome was similar in patients receiving winged and wingless HA, but the wingless type was associated with a higher rate of fusion between HA and lamina at 12 months post-operatively. PMID:22993674

  7. Developmental dysplasia of the hip

    MedlinePlus

    ... to keep the legs apart and turned outward (frog-leg position). This device will usually hold the ... Bracing devices may cause skin irritation. Differences in the lengths ... treatment. Untreated, hip dysplasia will lead to arthritis ...

  8. Monoarticular hip involvement in pseudogout.

    PubMed

    Kocyigit, Figen; Kuyucu, Ersin; Kocyigit, Ali

    2015-01-01

    Pseudogout is the acutest form of arthritis in the elderly. Although clinical manifestations vary widely, polyarticular involvement is typical mimicking osteoarthritis or rheumatoid arthritis. Monoarticular involvement is relatively rare and is generally provoked by another medical condition. There are reported cases of hip involvement by pseudogout in monoarticular form. However, all of the cases were presented as septic arthritis. In this report, we present a case of monoarticular hip involvement mimicking soft tissue abscess. We confirmed the pseudogout diagnosis after ultrasonographic evaluation of the involved hip joint and pathological and biochemical analysis of synovial fluid analysis. Diagnosis is important to avoid unnecessary medical and surgical treatment in cases of the bizarre involvement of hip in pseudogout. PMID:25838961

  9. Monoarticular Hip Involvement in Pseudogout

    PubMed Central

    Kocyigit, Figen; Kuyucu, Ersin; Kocyigit, Ali

    2015-01-01

    Pseudogout is the acutest form of arthritis in the elderly. Although clinical manifestations vary widely, polyarticular involvement is typical mimicking osteoarthritis or rheumatoid arthritis. Monoarticular involvement is relatively rare and is generally provoked by another medical condition. There are reported cases of hip involvement by pseudogout in monoarticular form. However, all of the cases were presented as septic arthritis. In this report, we present a case of monoarticular hip involvement mimicking soft tissue abscess. We confirmed the pseudogout diagnosis after ultrasonographic evaluation of the involved hip joint and pathological and biochemical analysis of synovial fluid analysis. Diagnosis is important to avoid unnecessary medical and surgical treatment in cases of the bizarre involvement of hip in pseudogout. PMID:25838961

  10. Abstract: Lightweight Authentication for HIP

    NASA Astrophysics Data System (ADS)

    Heer, Tobias

    In recent years numerous solutions for overcoming the architectural constraints of the Internet have emerged. One of the most promising among them is the Host Identity Protocol (HIP) [2], which was recently approved as an experimental standard by the IETF. HIP adds an additional protocol layer between TCP and IP to implement the Identifier/Locator split. Apart from mobility and multihoming, HIP supports host authentication, payload encryption, and a cryptographic namespace without requiring changes to the network infrastructure or network applications. However, especially mobile devices with tightly limited CPU resources are slowed down by HIP. Its poor performance on these mobile devices is a result of the extensive use of public-key (PK) cryptography for securing the main protocol functions.

  11. Fracture After Total Hip Replacement

    MedlinePlus

    ... er Total Hip Replacement cont. • Dislocation • Limb length inequality • Poor fracture healing • Repeat fracture • Lack of in- ... Surgeons (AAOS). To learn more about your orthopaedic health, please visit orthoinfo.org. Page ( 5 ) AAOS does ...

  12. Revision rate after short-stem total hip arthroplasty

    PubMed Central

    van Oldenrijk, Jakob; Molleman, Jeroen; Klaver, Michel; Poolman, Rudolf W; Haverkamp, Daniel

    2014-01-01

    Background and purpose The aim of short-stem total hip arthroplasty is to preserve proximal bone stock for future revisions, to improve biomechanical reconstruction, and to make minimally invasive approaches easier. It is therefore being increasingly considered to be a sound alternative to conventional total hip arthroplasty, especially for young and active patients. However, it is still unknown whether survival rates of short-stem hips match current standards. We made a systematic summary of reported overall survival after short-stem total hip arthroplasty. Materials and methods We conducted a systematic review of English, French, German, and Dutch literature. 2 assessors independently identified clinical studies on short-stem hip arthroplasty. After recalculating reported revision rates, we determined whether each implant had a projected revision rate of 10% or less at 10 years of follow-up or a revision rate per 100 observed component years of 1 or less. Stems were classified as “collum”, “partial collum”, or “trochanter-sparing”. Results and Interpretation We found 49 studies, or 51 cohorts, involving 19 different stems. There was a large increase in recent publications. The majority of studies included had a follow-up of less than 5 years. We found a large number of observational studies on “partial collum” and “trochanter-sparing” stems, demonstrating adequate survival rates at medium-term follow-up. Clinical evidence from “collum stem” studies was limited to a small number of studies with a medium-term follow-up period. These studies did not show a satisfactory overall survival rate. PMID:24694271

  13. Anchor-induced chondral damage in the hip

    PubMed Central

    Matsuda, Dean K.; Bharam, Srino; White, Brian J.; Matsuda, Nicole A.; Safran, Marc

    2015-01-01

    The purpose of this study is to investigate the outcomes from anchor-induced chondral damage of the hip, both with and without frank chondral penetration. A multicenter retrospective case series was performed of patients with chondral deformation or penetration during initial hip arthroscopic surgery. Intra-operative findings, post-surgical clinical courses, hip outcome scores and descriptions of arthroscopic treatment in cases requiring revision surgery and anchor removal are reported. Five patients (three females) of mean age 32 years (range, 16–41 years) had documented anchor-induced chondral damage with mean 3.5 years (range, 1.5–6.0 years) follow-up. The 1 o'clock position (four cases) and anterior and mid-anterior portals (two cases each) were most commonly implicated. Two cases of anchor-induced acetabular chondral deformation without frank penetration had successful clinical and radiographic outcomes, while one case progressed from deformation to chondral penetration with clinical worsening. Of the cases that underwent revision hip arthroscopy, all three had confirmed exposed hard anchors which were removed. Two patients have had clinical improvement and one patient underwent early total hip arthroplasty. Anchor-induced chondral deformation without frank chondral penetration may be treated with close clinical and radiographic monitoring with a low threshold for revision surgery and anchor removal. Chondral penetration should be treated with immediate removal of offending hard anchor implants. Preventative measures include distal-based portals, small diameter and short anchors, removable hard anchors, soft suture-based anchors, curved drill and anchor insertion instrumentation and attention to safe trajectories while visualizing the acetabular articular surface. PMID:27011815

  14. Increased Long-Term Cardiovascular Risk After Total Hip Arthroplasty

    PubMed Central

    Gordon, Max; Rysinska, Agata; Garland, Anne; Rolfson, Ola; Aspberg, Sara; Eisler, Thomas; Garellick, Göran; Stark, André; Hailer, Nils P.; Sköldenberg, Olof

    2016-01-01

    Abstract Total hip arthroplasty is a common and important treatment for osteoarthritis patients. Long-term cardiovascular effects elicited by osteoarthritis or the implant itself remain unknown. The purpose of the present study was to determine if there is an increased risk of late cardiovascular mortality and morbidity after total hip arthroplasty surgery. A nationwide matched cohort study with data on 91,527 osteoarthritis patients operated on, obtained from the Swedish Hip Arthroplasty Register. A control cohort (n = 270,688) from the general Swedish population was matched 1:3 to each case by sex, age, and residence. Mean follow-up time was 10 years (range, 7–21). The exposure was presence of a hip replacement for more than 5 years. The primary outcome was cardiovascular mortality after 5 years. Secondary outcomes were total mortality and re-admissions due to cardiovascular events. During the first 5 to 9 years, the arthroplasty cohort had a lower cardiovascular mortality risk compared with the control cohort. However, the risk in the arthroplasty cohort increased over time and was higher than in controls after 8.8 years (95% confidence interval [CI] 7.0–10.5). Between 9 and 13 years postoperatively, the hazard ratio was 1.11 (95% CI 1.05–1.17). Arthroplasty patients were also more frequently admitted to hospital for cardiovascular reasons compared with controls, with a rate ratio of 1.08 (95% CI 1.06–1.11). Patients with surgically treated osteoarthritis of the hip have an increased risk of cardiovascular morbidity and mortality many years after the operation when compared with controls. PMID:26871792

  15. Anchor-induced chondral damage in the hip.

    PubMed

    Matsuda, Dean K; Bharam, Srino; White, Brian J; Matsuda, Nicole A; Safran, Marc

    2015-01-01

    The purpose of this study is to investigate the outcomes from anchor-induced chondral damage of the hip, both with and without frank chondral penetration. A multicenter retrospective case series was performed of patients with chondral deformation or penetration during initial hip arthroscopic surgery. Intra-operative findings, post-surgical clinical courses, hip outcome scores and descriptions of arthroscopic treatment in cases requiring revision surgery and anchor removal are reported. Five patients (three females) of mean age 32 years (range, 16-41 years) had documented anchor-induced chondral damage with mean 3.5 years (range, 1.5-6.0 years) follow-up. The 1 o'clock position (four cases) and anterior and mid-anterior portals (two cases each) were most commonly implicated. Two cases of anchor-induced acetabular chondral deformation without frank penetration had successful clinical and radiographic outcomes, while one case progressed from deformation to chondral penetration with clinical worsening. Of the cases that underwent revision hip arthroscopy, all three had confirmed exposed hard anchors which were removed. Two patients have had clinical improvement and one patient underwent early total hip arthroplasty. Anchor-induced chondral deformation without frank chondral penetration may be treated with close clinical and radiographic monitoring with a low threshold for revision surgery and anchor removal. Chondral penetration should be treated with immediate removal of offending hard anchor implants. Preventative measures include distal-based portals, small diameter and short anchors, removable hard anchors, soft suture-based anchors, curved drill and anchor insertion instrumentation and attention to safe trajectories while visualizing the acetabular articular surface. PMID:27011815

  16. Hip resurfacing arthroplasty: short-term survivorship of 4,401 hips from the Finnish Arthroplasty Register

    PubMed Central

    2012-01-01

    Background and purpose Population-based registry data from the Nordic Arthroplasty Register Association (NARA) and from the National Joint Register of England and Wales have revealed that the outcome after hip resurfacing arthroplasty (HRA) is inferior to that of conventional total hip arthroplasty (THA). We analyzed the short-term survival of 4,401 HRAs in the Finnish Arthroplasty Register. Methods We compared the revision risk of the 4,401 HRAs from the Register to that of 48,409 THAs performed during the same time period. The median follow-up time was 3.5 (09) years for HRAs and 3.9 (09) years for THAs. Results There was no statistically significant difference in revision risk between HRAs and THAs (RR = 0.93, 95% CI: 0.781.10). Female patients had about double the revision risk of male patients (RR = 2.0, CI: 1.42.7). Hospitals that had performed 100 or more HRA procedures had a lower revision risk than those with less than 100 HRAs (RR = 0.6, CI: 0.40.9). Articular Surface Replacement (ASR, DePuy) had inferior outcome with higher revision risk than the Birmingham Hip Resurfacing implant (BHR, Smith & Nephew), the reference implant (RR = 1.8, CI: 1.22.7). Interpretation We found that HRA had comparable short-term survivorship to THA at a nationwide level. Implant design had an influence on revision rates. ASR had higher revision risk. Low hospital procedure volume worsened the outcome of HRA. Female patients had twice the revision risk of male patients. PMID:22616745

  17. DYSPLASIA OF HIP DEVELOPMENT: UPDATE

    PubMed Central

    Guarniero, Roberto

    2015-01-01

    The term “developmental dysplasia of the hip” (DDH) includes a wide spectrum of abnormalities that affect the hip during its growth, ranging from dysplasia to joint dislocation and going through different degrees of coxofemoral subluxation. The incidence of DDH is variable, and depends on a number of factors, including geographical location. Approximately one in 1,000 newborn infants may present hip dislocation and around 10 in 1,000 present hip instability. Brazil has an incidence of five per 1,000 in terms of findings of a positive Ortolani sign, which is the early clinical sign for detecting the disorder. The risk factors for DDH include: female sex, white skin color, primiparity, young mother, breech presentation at birth, family history, oligohydramnios, newborns with greater weight and height, and deformities of the feet or spine. Hip examinations should be routine for newborns, and should be emphasized in maternity units. Among newborns and infants, the diagnosis of DDH is preeminently clinical and is made using the Ortolani and Barlow maneuvers. Conventional radiography is of limited value for confirming the diagnosis of DDH among newborns, and ultrasound of the hip is the ideal examination. The treatment of DDH is challenging, both for pediatric orthopedists and for general practitioners. The objectives of the treatment include diagnosis as early as possible, joint reduction and stabilization of the hip in a secure position. Classically, treatment options are divided according to different age groups, at the time of diagnosis. PMID:27022528

  18. Good outcome of total hip replacement in patients with cerebral palsy.

    PubMed

    King, Garry; Hunt, Linda P; Wilkinson, J Mark; Blom, Ashley W

    2016-04-01

    Background and purpose - People with cerebral palsy (CP) often have painful deformed hips, but they are seldom treated with hip replacement as the surgery is considered to be high risk. However, few data are available on the outcome of hip replacement in these patients. Patients and methods - We linked Hospital Episode Statistics (HES) records to the National Joint Registry for England and Wales to identify 389 patients with CP who had undergone hip replacement. Their treatment and outcomes were compared with those of 425,813 patients who did not have CP. Kaplan-Meier estimates were calculated to describe implant survivorship and the curves were compared using log-rank tests, with further stratification for age and implant type. Reasons for revision were quantified as patient-time incidence rates (PTIRs). Nationally collected patient-reported outcomes (PROMS) before and 6 months after operation were compared if available. Cumulative mortality (Kaplan-Meier) was estimated at 90 days and at 1, 3, and 5 years. Results - The cumulative probability of revision at 5 years post-surgery was 6.4% (95% CI: 3.8-11) in the CP cohort as opposed to 2.9% (CI 2.9-3%) in the non-CP cohort (p < 0.001). Patient-reported outcomes showed that CP patients had worse pain and function preoperatively, but had equivalent postoperative improvement. The median improvement in Oxford hip score at 6 months was 23 (IQR: 14-28) in CP and it was 21 (14-28) in non-CP patients. 91% of CP patients reported good or excellent satisfaction with their outcome. The cumulative probability of mortality for CP up to 7 years was similar to that in the controls after stratification for age and sex. Interpretation - Hip replacement for cerebral palsy appears to be safe and effective, although implant revision rates are higher than those in patients without cerebral palsy. PMID:26863583

  19. Good outcome of total hip replacement in patients with cerebral palsy

    PubMed Central

    King, Garry; Hunt, Linda P; Wilkinson, J Mark; Blom, Ashley W

    2016-01-01

    Background and purpose — People with cerebral palsy (CP) often have painful deformed hips, but they are seldom treated with hip replacement as the surgery is considered to be high risk. However, few data are available on the outcome of hip replacement in these patients. Patients and methods — We linked Hospital Episode Statistics (HES) records to the National Joint Registry for England and Wales to identify 389 patients with CP who had undergone hip replacement. Their treatment and outcomes were compared with those of 425,813 patients who did not have CP. Kaplan-Meier estimates were calculated to describe implant survivorship and the curves were compared using log-rank tests, with further stratification for age and implant type. Reasons for revision were quantified as patient-time incidence rates (PTIRs). Nationally collected patient-reported outcomes (PROMS) before and 6 months after operation were compared if available. Cumulative mortality (Kaplan-Meier) was estimated at 90 days and at 1, 3, and 5 years. Results — The cumulative probability of revision at 5 years post-surgery was 6.4% (95% CI: 3.8–11) in the CP cohort as opposed to 2.9% (CI 2.9–3%) in the non-CP cohort (p < 0.001). Patient-reported outcomes showed that CP patients had worse pain and function preoperatively, but had equivalent postoperative improvement. The median improvement in Oxford hip score at 6 months was 23 (IQR: 14–28) in CP and it was 21 (14–28) in non-CP patients. 91% of CP patients reported good or excellent satisfaction with their outcome. The cumulative probability of mortality for CP up to 7 years was similar to that in the controls after stratification for age and sex. Interpretation — Hip replacement for cerebral palsy appears to be safe and effective, although implant revision rates are higher than those in patients without cerebral palsy. PMID:26863583

  20. Diagnosis of adverse local tissue reactions following metal-on-metal hip arthroplasty.

    PubMed

    Chalmers, Brian P; Perry, Kevin I; Taunton, Michael J; Mabry, Tad M; Abdel, Matthew P

    2016-03-01

    Metal-on-metal (MOM) bearing surfaces in hip arthroplasty have distinct advantages that led to the increase in popularity in North America in the early 2000s. However, with their increased use, concerns such as local cytotoxicity and hypersensitivity reactions leading to soft tissue damage and cystic mass formation (known collectively as adverse local tissue reactions (ALTR)) became apparent. The clinical presentation of ALTR is highly variable. The diagnosis of ALTR in MOM articulations in hip arthroplasty can be challenging and a combination of clinical presentation, physical examination, implant track record, component positioning, serum metal ion levels, cross-sectional imaging, histopathologic analysis, and consideration of alternative diagnoses are essential. PMID:26816329

  1. Septic hip dislocation in a child.

    PubMed

    Hua, Kuo-Shu; Huang, Yun-Yi; Shen, Dong-Lin; Chang, Ing-Lin; Chen, Shih-Jen

    2009-01-01

    A 4-year-old girl presented with pain and disability of right side hip of about 1-week duration. High-grade fever and upper respiratory tract infection were also noted. A pelvic computed tomography scan showed a dislocated hip accompanied by a huge intrapelvic abscess. Culture of pus from the hip showed Streptococcus pneumonia. Emergency arthrotomy, drainage of abscess and reduction of hip, and immobilization with a hip spica cast were undertaken. Thereafter, intravenous antibiotics were given for 6 weeks. The infection was resolved. At a 2-year follow-up, the clinical result was fair and the radiography showed persisting hip damage. PMID:20108613

  2. Structural design feasibility study of Space Station long spacer truss

    NASA Technical Reports Server (NTRS)

    Armand, Sasan C.; Funk, Gregory P.; Dohogne, Caroline A.

    1994-01-01

    The structural design and configuration feasibility of the long spacer truss assembly that will be used as part of the Space Station Freedom is the focus of this study. The structural analysis discussed herein is derived from the transient loading events presented in the Space Transportation System Interface Control Document (STS ICD). The transient loading events are liftoff, landing, and emergency landing loads. Quasi-static loading events were neglected in this study since the magnitude of the quasi-static acceleration factors is lower than that of the transient acceleration factors. Structural analysis of the proposed configuration of the long spacer truss with four longerons indicated that negative safety margins are possible. As a result, configuration changes were proposed. The primary configuration change suggested was to increase the number of truss longerons to six. The six-longeron truss appears to be a more promising structure than the four-longeron truss because it offers a positive margin of safety and more volume in its second bay (BAY2). This additional volume can be used for resupply of some of the orbital replacement units (such as a battery box). Note that the design effort on the long spacer truss has not fully begun and that calculations and reports of the negative safety margins are, to date, based on concept only.

  3. Structural design feasibility study of Space Station long spacer truss

    NASA Astrophysics Data System (ADS)

    Armand, Sasan C.; Funk, Gregory P.; Dohogne, Caroline A.

    1994-02-01

    The structural design and configuration feasibility of the long spacer truss assembly that will be used as part of the Space Station Freedom is the focus of this study. The structural analysis discussed herein is derived from the transient loading events presented in the Space Transportation System Interface Control Document (STS ICD). The transient loading events are liftoff, landing, and emergency landing loads. Quasi-static loading events were neglected in this study since the magnitude of the quasi-static acceleration factors is lower than that of the transient acceleration factors. Structural analysis of the proposed configuration of the long spacer truss with four longerons indicated that negative safety margins are possible. As a result, configuration changes were proposed. The primary configuration change suggested was to increase the number of truss longerons to six. The six-longeron truss appears to be a more promising structure than the four-longeron truss because it offers a positive margin of safety and more volume in its second bay (BAY2). This additional volume can be used for resupply of some of the orbital replacement units (such as a battery box). Note that the design effort on the long spacer truss has not fully begun and that calculations and reports of the negative safety margins are, to date, based on concept only.

  4. Improving electricity production in tubular microbial fuel cells through optimizing the anolyte flow with spiral spacers.

    PubMed

    Zhang, Fei; Ge, Zheng; Grimaud, Julien; Hurst, Jim; He, Zhen

    2013-04-01

    The use of spiral spacers to create a helical flow for improving electricity generation in microbial fuel cells (MFCs) was investigated in both laboratory and on-site tests. The lab tests found that the MFC with the spiral spacers produced more electricity than the one without the spiral spacers at different recirculation rates or organic loading rates, likely due to the improved transport/distribution of ions and electron mediators instead of the substrates because the organic removal efficiency was not obviously affected by the presence of the spiral spacers. The energy production in the MFC with the spiral spacers reached 0.071 or 0.073 kWh/kg COD in either vertical or horizontal installment. The examination of the MFCs installed in an aeration tank of a municipal wastewater treatment plant confirmed the advantage of using the spiral spacers. Those results demonstrate that spiral spacers could be an effective approach to improve energy production in MFCs. PMID:23500582

  5. X-Rays May Miss Hip Arthritis, Study Finds

    MedlinePlus

    ... with hip pain had X-ray evidence of osteoarthritis in the hip and only 21 percent of ... older subjects with high suspicion for clinical hip osteoarthritis did not have radiographic hip osteoarthritis, suggesting that ...

  6. Favorable outcome of a total hip arthroplasty with insufficient bone coverage of the roof reinforcement ring

    PubMed Central

    Judas, Fernando M.; Lucas, Francisco M.; Fonseca, Ruben L.

    2015-01-01

    Introduction Total hip arthroplasty in patients with developmental dysplasia of the hip can be a complex procedure due to acetabular and proximal femoral deformities. Presentation of case A 59-year-old male patient underwent a total hip arthroplasty for the treatment of end-stage dysplastic osteoarthritis. A roof reinforcement ring, a cemented polyethylene cup, and a cementless stem were used. A portion of the superior rim of the ring was uncovered by the host bone. Morsellized autogenous femoral-head graft was impacted to fill the space between the superior rim of the ring and the superior part of the dysplastic acetabulum. At the follow-up after 5-years, the patient had no complaints and was very satisfied with the operation result. The hip radiograph revealed no signs of instability of the acetabular component, and no bone graft resorption. Discussion Favorable results were described using metal rings and conical femoral stems for the treatment of the developmental dysplasia of the hip. The superior rim of the metal ring should be against host bone for 60% of its support. Despite the suboptimal implantation of the ring compromising, apparently, mechanical stability of the arthroplasty, the outcome was favorable. Conclusion This result can be supported by the good fixation of the metal ring to the pelvis with screws, the adequate orientation of both components of the total hip arthroplasty, and the bone graft incorporation. PMID:26453941

  7. Hip Resurfacing Arthroplasty in Treatment of Avascular Necrosis of the Femoral Head

    PubMed Central

    Pyda, Michał; Koczy, Bogdan; Widuchowski, Wojciech; Widuchowska, Małgorzata; Stołtny, Tomasz; Mielnik, Michał; Hermanson, Jacek

    2015-01-01

    Background Hip resurfacing is a conservative type of total hip arthroplasty but its use is controversial, especially in patients with osteonecrosis. The aim of this study was analysis of the clinical and radiographic outcomes of hip resurfacing in patients with osteonecrosis. Material/Methods Between 2007 and 2008, 30 hip resurfacing arthroplasties were performed due to osteoarthritis secondary to avascular necrosis of femoral head staged as Ficat III and IV. Patients were qualified to resurfacing arthroplasty when the extent of avascular necrosis using Kerboul’s method was <200° and the angle between avascular necrosis and head-neck junction was >20°. All patients were evaluated clinically and radiologically before and 60 months after the operation. Results The mean Harris Hip Score (HHS) score increased from 47.8 to 94.25 (p<0.05). Physical activity level (University of California, Los Angeles activity score – UCLA activity score) improved from 3.7 to 7.55 (p<0.05). No implant migration was observed. Conclusions Management of osteonecrosis of the hip with resurfacing arthroplasty seems to be effective in strictly-selected patients. PMID:25618763

  8. In-situ electrochemical study of interaction of tribology and corrosion in artificial hip prosthesis simulators.

    PubMed

    Yan, Yu; Dowson, Duncan; Neville, Anne

    2013-02-01

    The second generation Metal-on-Metal (MoM) hip replacements have been considered as an alternative to commonly used Polyethylene-on-Metal (PoM) joint prostheses due to polyethylene wear debris induced osteolysis. However, the role of corrosion and the biofilm formed under tribological contact are still not fully understood. Enhanced metal ion concentrations have been reported widely from hair, blood and urine samples of patients who received metal hip replacements and in isolated cases when abnormally high levels have caused adverse local tissue reactions. An understanding of the origin of metal ions is really important in order to design alloys for reduced ion release. Reciprocating pin-on-plate wear tester is a standard instrument to assess the interaction of corrosion and wear. However, more realistic hip simulator can provide a better understanding of tribocorrosion process for hip implants. It is very important to instrument the conventional hip simulator to enable electrochemical measurements. In this study, simple reciprocating pin-on-plate wear tests and hip simulator tests were compared. It was found that metal ions originated from two sources: (a) a depassivation of the contacting surfaces due to tribology (rubbing) and (b) corrosion of nano-sized wear particles generated from the contacting surfaces. PMID:23182693

  9. Perfusion MRI in hips with metal-on-metal and metal-on-polyethylene total hip arthroplasty

    PubMed Central

    Anwander, H.; Cron, G. O.; Rakhra, K.

    2016-01-01

    Objectives Hips with metal-on-metal total hip arthroplasty (MoM THA) have a high rate of adverse local tissue reactions (ALTR), often associated with hypersensitivity reactions. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) measures tissue perfusion with the parameter Ktrans (volume transfer constant of contrast agent). Our purpose was 1) to evaluate the feasibility of DCE-MRI in patients with THA and 2) to compare DCE-MRI in patients with MoM bearings with metal-on-polyethylene (MoP) bearings, hypothesising that the perfusion index Ktrans in hips with MoM THA is higher than in hips with MoP THA. Methods In this pilot study, 16 patients with primary THA were recruited (eight MoM, eight MoP). DCE-MRI of the hip was performed at 1.5 Tesla (T). For each patient, Ktrans was computed voxel-by-voxel in all tissue lateral to the bladder. The mean Ktrans for all voxels was then calculated. These values were compared with respect to implant type and gender, and further correlated with clinical parameters. Results There was no significant difference between the two bearing types with both genders combined. However, dividing patients by THA bearing and gender, women with MoM bearings had the highest Ktrans values, exceeding those of women with MoP bearings (0.067 min−1 versus 0.053 min−1; p-value < 0.05) and men with MoM bearings (0.067 min−1 versus 0.034 min−1; p-value < 0.001). Considering only the men, patients with MoM bearings had lower Ktrans than those with MoP bearings (0.034 min−1 versus 0.046 min−1; p < 0.05). Conclusion DCE-MRI is feasible to perform in tissues surrounding THA. Females with MoM THA show high Ktrans values in DCE-MRI, suggesting altered tissue perfusion kinematics which may reflect relatively greater inflammation. Cite this article: Dr P. E. Beaule. Perfusion MRI in hips with metal-on-metal and metal-on-polyethylene total hip arthroplasty: A pilot stud. Bone Joint Res 2016;5:73–79. DOI: 10.1302/2046-3758.53.2000572. PMID:26935768

  10. Development and characterization of 3D-printed feed spacers for spiral wound membrane systems.

    PubMed

    Siddiqui, Amber; Farhat, Nadia; Bucs, Szilárd S; Linares, Rodrigo Valladares; Picioreanu, Cristian; Kruithof, Joop C; van Loosdrecht, Mark C M; Kidwell, James; Vrouwenvelder, Johannes S

    2016-03-15

    Feed spacers are important for the impact of biofouling on the performance of spiral-wound reverse osmosis (RO) and nanofiltration (NF) membrane systems. The objective of this study was to propose a strategy for developing, characterizing, and testing of feed spacers by numerical modeling, three-dimensional (3D) printing of feed spacers and experimental membrane fouling simulator (MFS) studies. The results of numerical modeling on the hydrodynamic behavior of various feed spacer geometries suggested that the impact of spacers on hydrodynamics and biofouling can be improved. A good agreement was found for the modeled and measured relationship between linear flow velocity and pressure drop for feed spacers with the same geometry, indicating that modeling can serve as the first step in spacer characterization. An experimental comparison study of a feed spacer currently applied in practice and a 3D printed feed spacer with the same geometry showed (i) similar hydrodynamic behavior, (ii) similar pressure drop development with time and (iii) similar biomass accumulation during MFS biofouling studies, indicating that 3D printing technology is an alternative strategy for development of thin feed spacers with a complex geometry. Based on the numerical modeling results, a modified feed spacer with low pressure drop was selected for 3D printing. The comparison study of the feed spacer from practice and the modified geometry 3D printed feed spacer established that the 3D printed spacer had (i) a lower pressure drop during hydrodynamic testing, (ii) a lower pressure drop increase in time with the same accumulated biomass amount, indicating that modifying feed spacer geometries can reduce the impact of accumulated biomass on membrane performance. The combination of numerical modeling of feed spacers and experimental testing of 3D printed feed spacers is a promising strategy (rapid, low cost and representative) to develop advanced feed spacers aiming to reduce the impact of biofilm formation on membrane performance and to improve the cleanability of spiral-wound NF and RO membrane systems. The proposed strategy may also be suitable to develop spacers in e.g. forward osmosis (FO), reverse electrodialysis (RED), membrane distillation (MD), and electrodeionisation (EDI) membrane systems. PMID:26773488

  11. Evaluation of the patient with hip pain.

    PubMed

    Wilson, John J; Furukawa, Masaru

    2014-01-01

    Hip pain is a common and disabling condition that affects patients of all ages. The differential diagnosis of hip pain is broad, presenting a diagnostic challenge. Patients often express that their hip pain is localized to one of three anatomic regions: the anterior hip and groin, the posterior hip and buttock, or the lateral hip. Anterior hip and groin pain is commonly associated with intra-articular pathology, such as osteoarthritis and hip labral tears. Posterior hip pain is associated with piriformis syndrome, sacroiliac joint dysfunction, lumbar radiculopathy, and less commonly ischiofemoral impingement and vascular claudication. Lateral hip pain occurs with greater trochanteric pain syndrome. Clinical examination tests, although helpful, are not highly sensitive or specific for most diagnoses; however, a rational approach to the hip examination can be used. Radiography should be performed if acute fracture, dislocations, or stress fractures are suspected. Initial plain radiography of the hip should include an anteroposterior view of the pelvis and frog-leg lateral view of the symptomatic hip. Magnetic resonance imaging should be performed if the history and plain radiograph results are not diagnostic. Magnetic resonance imaging is valuable for the detection of occult traumatic fractures, stress fractures, and osteonecrosis of the femoral head. Magnetic resonance arthrography is the diagnostic test of choice for labral tears. PMID:24444505

  12. Basic Science Considerations in Primary Total Hip Replacement Arthroplasty

    PubMed Central

    Mirza, Saqeb B; Dunlop, Douglas G; Panesar, Sukhmeet S; Naqvi, Syed G; Gangoo, Shafat; Salih, Saif

    2010-01-01

    Total Hip Replacement is one of the most common operations performed in the developed world today. An increasingly ageing population means that the numbers of people undergoing this operation is set to rise. There are a numerous number of prosthesis on the market and it is often difficult to choose between them. It is therefore necessary to have a good understanding of the basic scientific principles in Total Hip Replacement and the evidence base underpinning them. This paper reviews the relevant anatomical and biomechanical principles in THA. It goes on to elaborate on the structural properties of materials used in modern implants and looks at the evidence base for different types of fixation including cemented and uncemented components. Modern bearing surfaces are discussed in addition to the scientific basis of various surface engineering modifications in THA prostheses. The basic science considerations in component alignment and abductor tension are also discussed. A brief discussion on modular and custom designs of THR is also included. This article reviews basic science concepts and the rationale underpinning the use of the femoral and acetabular component in total hip replacement. PMID:20582240

  13. [Total hip replacement with isoelastic prosthesis in animals (author's transl)].

    PubMed

    Muhr, O; Stockhusen, H; Mller, O

    1976-10-01

    Uncemented fixation and low-fraction materials are the basis of this experiment. Plastics with an elasticity similar to the bone ("isoelasticity") show very propitious material qualities. The direct cementless incorporation of test bodies must be checked. In 63 sheep isoelastic total hip joints were implanted. After 2 till 51 weeks the animals were sacrificed and 44 specimen of hips and organs were explored macroscopically, radiologically, spherimetrically and histologically. The result was: 1. Plastic hip prosthesis are incorporated in the bone, but the boundary layer is built by a collagenous fiber tissue. 2. Loosening brings resoption of the bone and expansion of the structural changed soft tissue. 3. The transformation of the femoral cortex to osteoporosis is considered possibly as the consequence of an insufficient biological transfer of the weight. 4. Fractures of the femoral prosthesis-stem could not be observed. 5. The radiology allows at the pelvis prosthesis a concret statement concerning stability, on the femoral part a probable one. 6. The abrasion is minimal, the tissue reaction to abrasion products is unessential. 7. Small abrasion particles are carried of by the lymph tract and stored in the first regional gland. A more distant spreading is not demonstrable. PMID:985179

  14. Polyethylene oxidation in total hip arthroplasty: evolution and new advances.

    PubMed

    Gómez-Barrena, Enrique; Medel, Francisco; Puértolas, José Antonio

    2009-01-01

    Ultra-high molecular weight polyethylene (UHMWPE) remains the gold standard acetabular bearing material for hip arthroplasty. Its successful performance has shown consistent results and survivorship in total hip replacement (THR) above 85% after 15 years, with different patients, surgeons, or designs. As THR results have been challenged by wear, oxidation, and liner fracture, relevant research on the material properties in the past decade has led to the development and clinical introduction of highly crosslinked polyethylenes (HXLPE). More stress on the bearing (more active, overweighted, younger patients), and more variability in the implantation technique in different small and large Hospitals may further compromise the clinical performance for many patients. The long-term in vivo performance of these materials remains to be proven. Clinical and retrieval studies after more than 5 years of in vivo use with HXLPE in THR are reviewed and consistently show a substantial decrease in wear rate. Moreover, a second generation of improved polyethylenes is backed by in vitro data and awaits more clinical experience to confirm the experimental improvements. Also, new antioxidant, free radical scavengers, candidates and the reinforcement of polyethylene through composites are currently under basic research.Oxidation of polyethylene is today significantly reduced by present formulations, and this forgiving, affordable, and wellknown material is still reliable to meet today's higher requirements in total hip replacement. PMID:20111694

  15. Cobalt chromium molybdenum metal combination for modular hip prostheses.

    PubMed

    Schmidt, M; Weber, H; Schön, R

    1996-08-01

    The development of a metal combination for modular hip systems was motivated by the following observations: (1) wear particles from polyethylene acetabular components can lead to a foreign body reaction and late aseptic loosening and (2) well designed all metal hip prostheses had very low wear rates, usually causing no osteolytic problems. The following challenges had to be met: (1) metal alloy with the maximum wear resistance; (2) the optimal clearance (difference in diameter) between 28-mm ball head and acetabular component; and (3) equipping modern, modular hip systems with metal combinations while maintaining compatibility with existing components. The realization of a metal combination consisted of the stable anchoring of a standard metal lining in a polyethylene insert that, combined, is intended to provide adequate load transfer and fit to either the bone cement bed or the titanium shell. The metal lining is manufactured from a carbide containing cobalt chromium molybdenum wrought alloy (Protasul-21WF). From 1988 to 1995, approximately 40,000 metal combinations (Metasul) were implanted. From these, 44 single components, with a maximum time in situ of 5.5 years, were retrieved and examined. The total linear wear rate averaged 2 to 5 micrometers per year per component after the initial conditioning phase. Under these conditions, particle induced late aseptic loosening is not to be expected. PMID:8769321

  16. Ceramic-on-ceramic bearings in total hip arthroplasty.

    PubMed

    Bierbaum, Benjamin E; Nairus, James; Kuesis, Daniel; Morrison, J Craig; Ward, Daniel

    2002-12-01

    The ideal bearing surface for total hip arthroplasty still is being sought. This bearing would be durable, cost-effective, easy to implant, inert, and produce minimal wear debris. Ceramic-on-ceramic bearings have continued to evolve and have enjoyed success in many European centers throughout the past 3 decades. A limited number of early reports from the United States discouraged widespread acceptance and use of ceramic-on-ceramic total hip arthroplasty. Once critically analyzed most of the failures from the early reports are attributable to design and material specific flaws. Vast improvements have been made in ceramic manufacturing leading to even more superior wear characteristics and higher burst strengths. The case for alumina-on-alumina ceramic bearings is becoming stronger as data accumulate clinically and in vitro. In a multicenter, prospective and randomized study, an alumina-on-alumina ceramic bearing is compared with a cobalt chrome-on-polyethylene bearing. After as many as 48 months there has been no significant difference in clinical performance between the two study groups. No ceramic head fracture or ceramic bearing failure has occurred. Therefore, this new alumina-on-alumina ceramic bearing is a safe option for total hip arthroplasty and may provide a more durable prosthesis especially in young and active patients. PMID:12461368

  17. Stabilising effect of dynamic interspinous spacers in degenerative low-grade lumbar instability.

    PubMed

    Holinka, Johannes; Krepler, Petra; Matzner, Michael; Grohs, Josef G

    2011-03-01

    The aim of the study was to investigate the stabilising effect of dynamic interspinous spacers (IS) in combination with interlaminar decompression in degenerative low-grade lumbar instability with lumbar spinal stenosis and to compare its clinical effect to patients with lumbar spinal stenosis in stable segments treated by interlaminar decompression only. Fifty consecutive patients with a minimum age of 60 years were scheduled for interlaminar decompression for clinically and radiologically confirmed lumbar spinal stenosis. Twenty-two of these patients (group DS) with concomitant degenerative low-grade lumbar instability up to 5 mm translational slip were treated by interlaminar decompression and additional dynamic IS implantation. The control group (D) with lumbar spinal stenosis in stable segments included 28 patients and underwent only interlaminar decompression. The mean follow-up was 46 months in group D and 44 months in group DS. A visual analogue scale (VAS), Oswestry Disability Index (ODI) and walking distance were evaluated pre- and postoperatively. The segmental instability was evaluated in flexion-extension X-rays. The implantation of an IS significantly reduced the lumbar instability on flexion-extension X-rays. At the time of follow-up walking distance, VAS and ODI showed a significant improvement in both groups, but no statistical significance between groups D and DS. Four patients each in groups D and DS had revision surgery during the period of evaluation. The stabilising effect of dynamic IS in combination with interlaminar decompression offers an opportunity for an effective treatment for degenerative low-grade lumbar instability with lumbar spinal stenosis. PMID:20419452

  18. In-vivo degradation of poly(carbonate-urethane) based spine implants

    PubMed Central

    Cipriani, E.; Bracco, P.; Kurtz, S.M.; Costa, L.; Zanetti, M.

    2013-01-01

    Fourteen explanted Dynesys® spinal devices were analyzed for biostability and compared with a reference, never implanted, control. Both poly(carbonate-urethane) (PCU) spacers and polyethylene-terephthalate (PET) cords were analyzed. The effect of implantation was evaluated through the observation of physical alterations of the device surfaces, evaluation of the chemical degradation and fluids absorption on the devices and examination of the morphological and mechanical features. PCU spacers exhibited a variety of surface damage mechanisms, the most significant being abrasion and localized, microscopic surface cracks. Evidence of oxidation and chain scission were detected on PCU spacers ATR–FTIR. ATR–FTIR, DSC and hardness measurements also showed a slight heterogeneity in the composition of PCU. The extraction carried out on the PCU spacers revealed the presence of extractable polycarbonate segments. One spacer and all PET cords visually exhibited the presence of adherent biological material (proteins), confirmed by the ATR–FTIR results. GC/MS analyses of the extracts from PET cords revealed the presence of biological fluids residues, mainly cholesterol derivatives and fatty acids, probably trapped into the fiber network. No further chemical alterations were observed on the PET cords. Although the observed physical and chemical damage can be considered superficial, greater attention must be paid to the chemical degradation mechanisms of PCU and to the effect of byproducts on the body. PMID:24043907

  19. 21 CFR 888.3360 - Hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... uncemented prosthesis. 888.3360 Section 888.3360 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis. (a) Identification. A hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis is a device intended to be...

  20. 21 CFR 888.3360 - Hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... uncemented prosthesis. 888.3360 Section 888.3360 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis. (a) Identification. A hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis is a device intended to be...

  1. 21 CFR 888.3360 - Hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... uncemented prosthesis. 888.3360 Section 888.3360 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF... Hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis. (a) Identification. A hip joint femoral (hemi-hip) metallic cemented or uncemented prosthesis is a device intended to be...

  2. Deciding to have knee or hip replacement

    MedlinePlus

    ... ways to help decide to have knee or hip replacement surgery or not. These may include reading about ... sports and other activities they enjoy. Knee or hip replacements are most often done in people who are ...

  3. Good results with cemented total hip arthroplasty in patients between 40 and 50 years of age

    PubMed Central

    de Kam, Daniël C J; Gardeniers, Jean W M; Veth, René P H

    2010-01-01

    Background and purpose Total hip arthroplasties in young patients have lower long-term survival rates than in older patients. We evaluated the use of a unique treatment protocol in patients aged between 40 and 50 years. In all cases we used a cemented THA, and for acetabular deficiencies we also used impacted bone grafts together with a cemented cup. Methods In 140 consecutive patients who were between 40 and 50 years of age at index surgery, 168 cemented total hip prostheses were evaluated after a mean follow-up time of 10 (2–19) years. Acetabular deficiencies were reconstructed with wire meshes and impacted bone grafts with a cemented cup (70 hips). During follow-up, 18 patients died (27 hips); in this group 3 hips (3 patients) had been revised. None of the patients were lost to follow-up. In all surviving patients, clinical assessment was performed with hip-score questions and all radiographs were evaluated. Results All clinical questionnaires showed an improved clinical hip score. 29 hips (17%) were revised after a mean of 8 (0.3–18) years. Kaplan-Meier survival analysis showed a survival of 88% (95% CI: 82–94) after 10 years with revision of either component for any reason. Survival with endpoint revision for aseptic loosening of either component was 94% (95% CI: 90–99) after 10 years. Interpretation Cemented implants in young patients have satisfying long-term results. Reconstruction of acetabular deficiencies with impacted bone grafts show promising results. PMID:20367411

  4. A stature-specific concept for uncemented, primary total hip arthroplasty

    PubMed Central

    Omlor, Georg W; Ullrich, Hannah; Krahmer, Knut; Jung, Alexander; Aldinger, Günther

    2010-01-01

    Background and purpose Variations in hip anatomy limit the femoral canal fit of standard uncemented hip stems. In addition, there are still issues with leg length discrepancy and offset reconstruction, potentially resulting in impingement, dislocation, and wear. Modular stems with different shapes for femoral canal fit and multiple neck options may improve the outcome and reduce complications. Patients and methods 173 patients (190 hips) received an uncemented THA with 1 of 2 different stem shapes for canal fit and a modular neck for stature-specific hip reconstruction. Median follow-up time was 9 (7–13) years. During the follow-up period, 20 patients died (22 hips) and 12 patients (13 hips) were lost to follow-up. 155 hips were available for evaluation, including clinical and radiological outcome. Results 1 stem was revised for a periprosthetic fracture following trauma; 10 cups and 2 modular necks were revised (1 for breakage and 1 during cup revision). At 10 years, stem survival was 100%, modular neck survival was 99% (CI: 95–100), and cup survival was 94% (CI: 87–97). No leg length discrepancies were measured in 96% of cases. Offset with anatomic lateralization was achieved in 98%. Median Harris hip score was 94 (47–100) and median Merle d'Aubigné score was 16 (10–18). Relevant radiolucent lines and osteolysis were not found. Interpretation The uncemented modular neck, dual-stem system used in this series allows accurate reconstruction of the joint by adapting the implant to the needs of the patient. This may improve the outcome of primary THA, which is supported by the results of this medium-term follow-up evaluation. PMID:20146639

  5. Bone impregnated hip screw in femoral neck fracture: Clinicoradiological results

    PubMed Central

    Sundar Raj, PK; Nuuman, Jiju A; Pattathil, Amish Sunder

    2015-01-01

    Background: Femoral neck fractures are treated either by internal fixation or arthroplasty. Usually, cannulated cancellous screws are used for osteosynthesis of fracture neck of femur. The bone impregnated hip screw (BIHS) is an alternative implant, where osteosyntehsis is required in femoral neck fracture. Materials and Methods: The BIHS is a hollow screw with thread diameter 8.3 mm, shank diameter 6.5 mm and wall thickness 2.2 mm and holes in the shaft of the screw with diameter 2 mm, placed in a staggered fashion. Biomechanical and animal experimental studies were done. Clinical study was done in two phases: Phase 1 in a group of volunteers, only with BIHS was used in a pilot study and phase 2 comparative study was done in a group with AO cannulated screws and the other group treated with BIHS. Results: In the phase 1 study, out of 15 patients, only one patient had delayed union. In phase 2, there were 78 patients, 44 patients in BIHS showed early union, compared to the rest 34 cases of AO cannulated screws Out of 44 patients with BIHS, 41 patients had an excellent outcome, 2 had nonunions and one implant breakage was noted. Conclusions: Bone impregnated hip screw has shown to provide early solid union since it incorporates the biomechanical principles and also increases the osteogenic potential and hence, found superior to conventional cannulated cancellous screw. PMID:26015608

  6. Hip replacement in femoral head osteonecrosis: current concepts

    PubMed Central

    Scaglione, Michelangelo; Fabbri, Luca; Celli, Fabio; Casella, Francesco; Guido, Giulio

    2015-01-01

    Summary Osteonecrosis of the femoral head is a destructive disease that usually affects young adults with high functional demands and can have devastating effects on hip joint. The treatment depends on extent and location of the necrosis lesion and on patient’s factors, that suggest disease progression, collapse probability and also implants survival. Non-idiopathic osteonecrosis patients had the worst outcome. There is not a gold standard treatment and frequently it is necessary a multidisciplinary approach. Preservation procedures of the femoral head are the first choice and can be attempted in younger patients without head collapse. Replacement procedure remains the main treatment after failure of preserving procedures and in the late-stage ONFH, involving collapse of the femoral head and degenerative changes to the acetabulum. Resurfacing procedure still has good results but the patient selection is a critical factor. Total hip arthroplasties had historically poor results in patients with osteonecrosis. More recently, reports have shown excellent results, but implant longevity and following revisions are still outstanding problems. PMID:27134633

  7. Effect of component design in retrieved bipolar hip hemiarthroplasty systems.

    PubMed

    Hess, Matthew D; Baker, Erin A; Salisbury, Meagan R; Kaplan, Lige M; Greene, Ryan T; Greene, Perry W

    2013-09-01

    Primary articulation of bipolar hemiarthroplasty systems is at the femoral head-liner interface. The purpose of this study was to compare observed damage modes on 36 retrieved bipolar systems with implant, demographic, intraoperative, and radiographic data to elucidate the effects of component design, specifically locking mechanism, on clinical performance. Retrieved bipolar hip hemiarthroplasty systems of 3 different design types were obtained, disassembled, and evaluated macro- and microscopically for varying modes of wear, including abrasion, burnishing, embedding, scratching, and pitting. Clinical record review and radiographic analysis were performed by a senior orthopedic surgery resident. Average bipolar hip hemiarthroplasty system term of service was 46 months (range, 0.27-187 months). All devices contained wear debris captured within the articulating space between the femoral head and liner. In 31% of patients without infection, lucency was observed on immediate prerevision radiographs. The system with a leaf locking mechanism showed significantly increased radiographically observed osteolysis (P=.03) compared with a system with a stopper ring locking mechanism. In addition, implant design and observed damage modes, including pitting and third-body particle embedding, were significantly associated with radiographically observed osteolysis. PMID:24025011

  8. Stable fixation but unpredictable bone remodelling around the Lord stem: minimum 23-year follow-up of 66 total hip arthroplasties.

    PubMed

    Zügner, Roland; Tranberg, Roy; Herberts, Peter; Romanus, Bertil; Kärrholm, Johan

    2013-04-01

    Early designs of uncemented hip implants turned out to be failures mainly because the prerequisites for durable implant fixation were unknown. One exception was the chrome-cobalt stem of the Madreporic Lord prosthesis. We prospectively studied this prosthetic design in 107 hips that underwent surgery in 1979-1986. At the last follow-up, five stems and 54 cups had been revised, corresponding to stem and cup survival rates of 92%±3% and 45%±5% at 26years. In all, 66 hips with remaining Lord stems were available for clinical follow-up 26years (24-29) after the index operation. The mean total Harris hip and pain scores were 81 (SD 14) and 41 (SD 5). PMID:23142437

  9. Arthroprosthetic cobaltism and pseudotumour also occur in patients with small diameter femoral ball head metal-on-metal total hip arthroplasties

    PubMed Central

    Roessler, Philip P; Witt, Florian; Efe, Turgay; Schmitt, Jan

    2014-01-01

    Metal-on-metal implants have been widely discredited in public during the past few months. At the same time patients' awareness has risen leading to an increased number of consultations regarding the topic. As hip resurfacings and total hip arthroplasties with large diameter femoral ball heads are already known for excessive metal wear, even small diameter ball heads with low friction get into focus now. We report a case of a 75-year-old man with recurrent hip pain almost 14 years after low friction metal-on-metal total hip arthroplasty. In addition to elevated serum cobalt levels, a type IV sensitivity reaction to cobalt could be noted. Explantation of a highly worn small diameter femoral ball head as well as development of the so-called pseudotumour indicate that all patients should be screened for signs of metal wear regardless of their specific risk factors or the type of metal-on-metal implant. PMID:24682139

  10. Alternative process for thin layer etching: Application to nitride spacer etching stopping on silicon germanium

    SciTech Connect

    Posseme, N. Pollet, O.; Barnola, S.

    2014-08-04

    Silicon nitride spacer etching realization is considered today as one of the most challenging of the etch process for the new devices realization. For this step, the atomic etch precision to stop on silicon or silicon germanium with a perfect anisotropy (no foot formation) is required. The situation is that none of the current plasma technologies can meet all these requirements. To overcome these issues and meet the highly complex requirements imposed by device fabrication processes, we recently proposed an alternative etching process to the current plasma etch chemistries. This process is based on thin film modification by light ions implantation followed by a selective removal of the modified layer with respect to the non-modified material. In this Letter, we demonstrate the benefit of this alternative etch method in term of film damage control (silicon germanium recess obtained is less than 6 A), anisotropy (no foot formation), and its compatibility with other integration steps like epitaxial. The etch mechanisms of this approach are also addressed.

  11. Noise from total hip replacements

    PubMed Central

    Wyatt, M. C.; Jesani, S.; Frampton, C.; Devane, P.; Horne, J. G.

    2014-01-01

    Objectives Our study aimed to examine not only the incidence but also the impact of noise from two types of total hip replacement articulations: ceramic-on-ceramic and ceramic-on-polyethylene. Methods We performed a case-controlled study comparing subjective and objective questionnaire scores of patients receiving a ceramic-on-ceramic or a ceramic-on-polyethylene total hip replacement by a single surgeon. Results There was a threefold higher incidence of noise from patients in the ceramic-on-ceramic group compared with the control group. The impact of this noise was significant for patients both subjectively and objectively. Conclusions This study reports a high patient impact of noise from ceramic-on-ceramic total hip replacements. This has led to a change in practice by the principal author. Cite this article: Bone Joint Res 2014;3:183–6. PMID:24920252

  12. [Ceramic-on-ceramic bearings in total hip arthroplasty (THA)].

    PubMed

    Sentürk, U; Perka, C

    2015-04-01

    The main reason for total hip arthroplasty (THA) revision is the wear-related aseptic loosening. Younger and active patients after total joint replacement create high demands, in particular, on the bearings. The progress, especially for alumina ceramic-on-ceramic bearings and mixed ceramics have solved many problems of the past and lead to good in vitro results. Modern ceramics (alumina or mixed ceramics containing alumina) are extremely hard, scratch-resistant, biocompatible, offer a low coefficient of friction, superior lubrication and have the lowest wear rates in comparison to all other bearings in THA. The disadvantage of ceramic is the risk of material failure, i.e., of ceramic fracture. The new generation of mixed ceramics (delta ceramic), has reduced the risk of head fractures to 0.03-0.05 %, but the risk for liner fractures remains unchanged at about 0.02 %. Assuming a non-impinging component implantation, ceramic-on-ceramic bearings have substantial advantages over all other bearings in THA. Due to the superior hardness, ceramic bearings produce less third body wear and are virtually impervious to damage from instruments during the implantation process. A specific complication for ceramic-on-ceramic bearings is "squeaking". The high rate of reported squeaking (0.45 to 10.7 %) highlights the importance of precise implant positioning and the stem and patient selection. With precise implant positioning this problem is rare with many implant designs and without clinical relevance. The improved tribology and the presumable resulting implant longevity make ceramic-on-ceramic the bearing of choice for young and active patients. PMID:25874400

  13. Characterization of wear in composite material orthopaedic implants. Part II: The implant/bone interface.

    PubMed

    Albert, K; Schledjewski, R; Harbaugh, M; Bleser, S; Jamison, R; Friedrich, K

    1994-01-01

    Carbon fiber/PEEK polymer (C/PEEK) composite materials are being developed for use as orthopaedic implant materials. Wear is an issue of increasing importance in orthopaedic implants; particulate debris generated by the wearing of biomaterials may be a causal factor leading to osteolysis and implant loosening. Therefore, numerical and experimental studies were completed to characterize the wear of C/PEEK composite materials in comparison to current orthopaedic implant materials. Finite element analyses (FEA) of a composite material hip stem implanted in a femur and loaded at 890 N determined that peak contact stresses will occur at the proximal-medial and distal regions of the implant. These contact stresses were found to be below 1.0 MPa over most of the implant surface; however the peak stress in the proximal-medial region was 1.8 MPa and higher still at the distal portion of the stem. In vivo forces result in contact stress values up to 9.0 MPa. The composite implant exhibited 10-40% lower contact stresses in the distal region compared to a titanium-alloy implant of identical design. Composite material wear samples were slid against porous hydroxylapatite (HA) to simulate the stem/bone interface. An identical series of experiments was run for comparison to a current orthopaedic implant material--Ti6A14V titanium alloy. Two domains of motion were studied; a composite ring-on-HA disc large amplitude sliding wear test; and a composite pin-on-HA disc small amplitude fretting regimen. Nominal contact pressures during testing were 1.4 MPa and 7.6 MPa for sliding and fretting tests, respectively. Fretting and sliding abrasive wear tests resulted in the composite material exhibiting a lower wear rate than the titanium-alloy. The magnitude of the difference was greatly dependent on the contact pressures, sliding amplitudes, and counterface material properties. PMID:7950869

  14. 21 CFR 888.3390 - Hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint femoral (hemi-hip) metal/polymer... § 888.3390 Hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis. (a) Identification. A hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis is a...

  15. 21 CFR 888.3390 - Hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Hip joint femoral (hemi-hip) metal/polymer... § 888.3390 Hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis. (a) Identification. A hip joint femoral (hemi-hip) metal/polymer cemented or uncemented prosthesis is a...

  16. 21 CFR 888.3380 - Hip joint femoral (hemi-hip) trunnion-bearing metal/polyacetal cemented prosthesis.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Hip joint femoral (hemi-hip) trunnion-bearing... Devices § 888.3380 Hip joint femoral (hemi-hip) trunnion-bearing metal/polyacetal cemented prosthesis. (a) Identification. A hip joint femoral (hemi-hip) trunnion-bearing metal/polyacetal cemented prosthesis is a...

  17. 21 CFR 888.3380 - Hip joint femoral (hemi-hip) trunnion-bearing metal/polyacetal cemented prosthesis.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Hip joint femoral (hemi-hip) trunnion-bearing... Devices § 888.3380 Hip joint femoral (hemi-hip) trunnion-bearing metal/polyacetal cemented prosthesis. (a) Identification. A hip joint femoral (hemi-hip) trunnion-bearing metal/polyacetal cemented prosthesis is a...

  18. In vivo biostability of polymeric spine implants: retrieval analyses from a United States investigational device exemption study.

    PubMed

    Shen, Ming; Zhang, Kai; Koettig, Petra; Welch, William C; Dawson, John M

    2011-11-01

    The Dynesys System for stabilizing the lumbar spine was first surgically implanted in Europe in 1994. In 2003, a prospective, randomized, investigational device exemption clinical trial of the system for non-fusion dynamic stabilization began. Polycarbonate urethane (PCU) and polyethylene terephthalate (PET) components explanted from four patients who had participated in the study were analyzed for biostability. Components had been implanted 9-19 months. The explanted components were visually inspected and digitally photographed. Scanning electron microscopy was used to analyze the surface of the spacers. The chemical and molecular properties of the retrieved spacers and cords were quantitatively compared with lot-matched, shelf-aged, components that had not been implanted using attenuated total reflection Fourier transform infrared (FTIR) and gel permeation chromatography (GPC). FTIR analyses suggested that the explanted spacers exhibited slight surface chemical changes but were chemically unchanged below the surface and in the center. New peaks that could be attributed to biodegradation of PCU were not observed. The spectral analyses for the cords revealed that the PET cords were chemically unchanged at both the surface and the interior. Peaks associated with the PET biodegradation were not detected. GPC results did not identify changes to the distributions of molecular weights that might be attributed to biodegradation of either PCU spacers or PET cords. The explanted condition of the retrieved components demonstrated the biostability of both PCU spacers and PET cords that had been in vivo for up to 19 months. PMID:21538208

  19. Hip arthroscopy. The supine position.

    PubMed

    Byrd, J W

    2001-10-01

    Hip arthroscopy is an effective technique. It can be performed successfully either supine or in the lateral position, but there appear to be modest advantages of the supine approach. Arthroscopy offers a less invasive alternative to arthrotomy for traditionally recognized forms of hip pathology, such as loose bodies or impinging osteophytes. Arthroscopy also offers a method of treatment for many conditions (including labral tears, acute articular injuries, and damage to the ligamentum teres) that previously went unrecognized and untreated. In the past, these patients were simply resigned to living within the constraints of their symptoms. Several dictums about hip arthroscopy must be acknowledged. First, the key to a successful outcome lies in proper patient selection. A technically well-executed procedure will fail when performed for the wrong reason, or when the outcome fails to meet the patient's expectations. Second, the patient must be properly positioned for the procedure to go well. Poor positioning will assure a difficult procedure. Third, simply gaining access to the hip joint is not an outstanding technical accomplishment. The paramount issue is accessing the joint in as atraumatic a fashion as possible. Due to its constrained architecture and dense soft tissue envelope, the potential for inadvertent iatrogenic scope trauma is significant and, perhaps unavoidable to some extent. Therefore, every reasonable step should be taken to keep this concern to a minimum. Perform the procedure as carefully as possible and be certain that it is being performed for the right reason. After accessing the joint, the techniques of operative arthroscopy for the hip employ existing strategies established in other joints. Because of the restraints imposed by the hip, however, technical deficiencies may be more apparent. PMID:11675882

  20. Femoral head diameter considerations for primary total hip arthroplasty.

    PubMed

    Girard, J

    2015-02-01

    The configuration of total hip arthroplasty (THA) implants has constantly evolved since they were first introduced. One of the key components of THA design is the diameter of the prosthetic femoral head. It has been well established that the risk of dislocation is lower as the head diameter increases. But head diameter impacts other variables beyond joint stability: wear, cam-type impingement, range of motion, restoration of biomechanics, proprioception and groin pain. The introduction of highly cross-linked polyethylene and hard-on-hard bearings has allowed surgeons to implant large-diameter heads that almost completely eliminate the risk of dislocation. But as a result, cup liners have become thinner. With femoral head diameters up to 36 mm, the improvement in joint range of motion, delay in cam-type impingement and reduction in dislocation risk have been clearly demonstrated. Conversely, large-diameter heads do not provide any additional improvements. If an "ecologically sound" approach to hip replacement is embraced (e.g. keeping the native femoral head diameter), hip resurfacing with a metal-on-metal bearing must be carried out. The reliability of large-diameter femoral heads in the longer term is questionable. Large-diameter ceramic-on-ceramic bearings may be plagued by the same problems as metal-on-metal bearings: groin pain, squeaking, increased stiffness, irregular lubrication, acetabular loosening and notable friction at the Morse taper. These possibilities require us to be extra careful when using femoral heads with a diameter greater than 36 mm. PMID:25596984

  1. Spontaneous modular femoral head dissociation complicating total hip arthroplasty.

    PubMed

    Talmo, Carl T; Sharp, Kinzie G; Malinowska, Magdalena; Bono, James V; Ward, Daniel M; LaReau, Justin

    2014-06-01

    Modular femoral heads have been used successfully for many years in total hip arthroplasty. Few complications have been reported for the modular Morse taper connection between the femoral head and trunnion of the stem in metal-on-polyethylene bearings. Although there has always been some concern over the potential for fretting, corrosion, and generation of particulate debris at the modular junction, this was not considered a significant clinical problem. More recently, concern has increased because fretting and corrosive debris have resulted in rare cases of pain, adverse local tissue reaction, pseudotumor, and osteolysis. Larger femoral heads, which have gained popularity in total hip arthroplasty, are suspected to increase the potential for local and systemic complications of fretting, corrosion, and generation of metal ions because of greater torque at the modular junction. A less common complication is dissociation of the modular femoral heads. Morse taper dissociation has been reported in the literature, mainly in association with a traumatic event, such as closed reduction of a dislocation or fatigue fracture of the femoral neck of a prosthesis. This report describes 3 cases of spontaneous dissociation of the modular prosthetic femoral head from the trunnion of the same tapered titanium stem because of fretting and wear of the Morse taper in a metal-on-polyethylene bearing. Continued clinical and scientific research on Morse taper junctions is warranted to identify and prioritize implant and surgical factors that lead to this and other types of trunnion failure to minimize complications associated with Morse taper junctions as hip implants and surgical techniques continue to evolve. PMID:24972443

  2. Have cementless and resurfacing components improved the medium-term results of hip replacement for patients under 60 years of age?

    PubMed Central

    Mason, James; Baker, Paul; Gregg, Paul J; Porter, Martyn; Deehan, David J; Reed, Mike R

    2015-01-01

    Background and purpose The optimal hip replacement for young patients remains unknown. We compared patient-reported outcome measures (PROMs), revision risk, and implant costs over a range of hip replacements. Methods We included hip replacements for osteoarthritis in patients under 60 years of age performed between 2003 and 2010 using the commonest brand of cemented, cementless, hybrid, or resurfacing prosthesis (11,622 women and 13,087 men). The reference implant comprised a cemented stem with a conventional polyethylene cemented cup and a standard-sized head (28- or 32-mm). Differences in implant survival were assessed using competing-risks models, adjusted for known prognostic influences. Analysis of covariance was used to assess improvement in PROMs (Oxford hip score (OHS) and EQ5D index) in 2014 linked procedures. Results In males, PROMs and implant survival were similar across all types of implants. In females, revision was statistically significantly higher in hard-bearing and/or small-stem cementless implants (hazard ratio (HR) = 4) and resurfacings (small head sizes (< 48 mm): HR = 6; large head sizes (≥ 48 mm): HR = 5) when compared to the reference cemented implant. In component combinations with equivalent survival, women reported significantly greater improvements in OHS with hybrid implants (22, p = 0.006) and cementless implants (21, p = 0.03) (reference, 18), but similar EQ5D index. For men and women, National Health Service (NHS) costs were lowest with the reference implant and highest with a hard-bearing cementless replacement. Interpretation In young women, hybrids offer a balance of good early functional improvement and low revision risk. Fully cementless and resurfacing components are more costly and do not provide any additional benefit for younger patients. PMID:25285617

  3. Obturator dislocation of the hip.

    PubMed

    Toms, A D; Williams, S; White, S H

    2001-01-01

    We describe two patients with obturator dislocation of the hip which was irreducible by described techniques of closed reduction. The first required open reduction using the iliofemoral approach with release of rectus femoris. The second was treated on a traction table which allowed disengagement of the head and, when combined with simultaneous lateral traction, adduction and gradual release of the longitudinal traction, facilitated a smooth reduction. Since the hip is stable in flexion, early mobilisation in an extension-limiting brace avoids the prolonged bed rest traditionally recommended for this injury. PMID:11245517

  4. Hip-Hop and the Academic Canon

    ERIC Educational Resources Information Center

    Abe, Daudi

    2009-01-01

    Over the last 30 years, the hip-hop movement has risen from the margins to become the preeminent force in US popular culture. In more recent times academics have begun to harness the power of hip-hop culture and use it as a means of infusing transformative knowledge into the mainstream academic discourse. On many college campuses, hip-hop's…

  5. Hip Replacement - Multiple Languages: MedlinePlus

    MedlinePlus

    ... Hip Replacement (Arabic) العربية Bilingual PDF Health Information Translations Bosnian (Bosanski) Total Hip Replacement Potpuna zamjena kuka - Bosanski (Bosnian) Bilingual PDF Health Information Translations Chinese - Simplified (简体中文) Total Hip Replacement 全髋关节置换 - 简体中文 ( ...

  6. Hip-Hop and the Academic Canon

    ERIC Educational Resources Information Center

    Abe, Daudi

    2009-01-01

    Over the last 30 years, the hip-hop movement has risen from the margins to become the preeminent force in US popular culture. In more recent times academics have begun to harness the power of hip-hop culture and use it as a means of infusing transformative knowledge into the mainstream academic discourse. On many college campuses, hip-hop's

  7. New joints for the Millennium: wear control in total replacement hip joints.

    PubMed

    Dowson, D

    2001-01-01

    Hip joint replacement is described as the greatest achievement in orthopaedic surgery in the twentieth century. The field has been dominated for some forty years by implants based upon metallic femoral heads and stems and polymeric acetabular cups. At the dawn of the new Millennium, many alternative materials and designs are now being proposed or evaluated. The reasons for these developments and the current contributions of engineering science and tribology to advances in hip replacement are discussed. Illustrations are presented of the significant changes being proposed or introduced. While the new designs of total hip replacements offer exciting engineering contributions to the future of joint replacement, the long-term benefits to patients will depend upon the biological response to the new devices. PMID:11521758

  8. A finite element method comparison of wear in two metal-on-metal total hip prostheses.

    PubMed

    Cosmi, F; Hoglievina, M; Fancellu, G; Martinelli, B

    2006-11-01

    The contact mechanics of two metal-on-metal (MOM) total hip prostheses was studied by means of the finite element method (FEM). The purpose of the work was to compare two total hip replacements (Durom and Metasul) with regard to the amount of wear debris released. Wear on the bearing surfaces was evaluated following Reye hypotheses from the pressure distribution, computed by means of three-dimensional FEM models; an approximate analytical model based on Hertz contact theory has also been developed and discussed. The results show that in the dry friction condition the Durom joint releases almost twice as much wear volume as produced by the Metasul joint. Therefore, while Durom implants can improve hip stability by increasing the prosthetic impingement-free range of motion (PIF-ROM), Metasul prostheses can be a valuable solution whenever wear represents a critical choice factor. PMID:17236520

  9. Failure of a novel ceramic-on-ceramic hip resurfacing prosthesis.

    PubMed

    Matharu, Gulraj S; Daniel, Joseph; Ziaee, Hena; McMinn, Derek J W

    2015-03-01

    We report the early failure of five ceramic-on-ceramic hip resurfacings (CoCHRs). The ceramic used for the acetabular liner was a novel ceramic-composite (two thirds polyurethane and one third alumina ceramic). All cases were revised for increasing metal ion levels (blood cobalt 3.93-208.0 μg/l and chromium 1.57-17.5 μg/l) due to ceramic liner fracture and/or accelerated wear of the ceramic femoral head coating. Patients underwent bearing exchange and revision using primary hip arthroplasty implants at a mean of 3.0 years following CoCHR. Intraoperatively all patients had metallosis. At 1 to 2 years of follow-up blood metal ions normalized with no complications. We do not recommend this particular type of ceramic-on-ceramic bearing for hip resurfacing. PMID:25453631

  10. Musculoskeletal-based finite element analysis of femur after total hip replacement.

    PubMed

    Meena, Vijay K; Kumar, Mohit; Pundir, Amit; Singh, Suman; Goni, Vijay; Kalra, Parveen; Sinha, Ravindra K

    2016-06-01

    This article evaluates the effect of stress variation on adult femur following total hip replacement using musculoskeletal-based finite element analysis. The aim was to study the changes in stress distribution in the femur after total hip replacement by providing simulated in vivo loading and boundary conditions. The loading and boundary conditions were generated using a musculoskeletal modelling software 'AnyBody' and were applied on femur model, generated from the computed tomography (CT) scan data for standing posture of male patient. The results showed considerable variation in stress distribution pattern in the femur before and after total hip replacement, the metallic implant taking major loads of human body and transferring very less loads to the femur. PMID:27006421

  11. Highly cross-linked polyethylene in hip resurfacing arthroplasty: long-term follow-up.

    PubMed

    Amstutz, Harlan C; Takamura, Karren M; Ebramzadeh, Edward; Le Duff, Michel J

    2015-01-01

    Highly cross-linked polyethylene (XLPE) has improved wear properties. This study reports the results of a small series of patients treated over 10 years ago with a metal-on-XLPE hip resurfacing.A total of 21 hips in 20 patients received a hip resurfacing with a cobalt-chromium metal femoral head and metal-backed acetabular cup lined with a XLPE insert and were retrospectively studied. Kaplan-Meier Survivorship was calculated.Five patients who had initial extreme cystic disease in the femoral head failed due to femoral loosening. Survivorship was 95.2% at 5 years and 81.0% at 10 years.We found that XLPE wear was not implicated in these failures, which were primarily attributed to poor bone quality of the femoral head, early bone preparation, cementing technique and excessive head reaming to near the neck diameter, necessitated for the implantation of a thick two-part socket. PMID:25362872

  12. MODULUS Stem for Developmental Hip Dysplasia: Long-term Follow-up.

    PubMed

    Benazzo, Francesco M; Piovani, Lucio; Combi, Alberto; Perticarini, Loris

    2015-10-01

    Between October 2001 and December 2010, 143 patients with developmental dysplasia underwent hip arthroplasty surgery using a conical stem with modular necks (MODULUS system, Lima Corporate, Villanova di San Daniele del Friuli, Italy). Thirty (21.0%) patients had both hips replaced, for a total of 173 implants. The mean age at the time of surgery was 55 years (range: 22-81 years). The mean follow-up was 87 months (range: 36-146 months); average Harris Hip Score increased from 42 (range: 23-65) preoperatively to 92 (range: 76-100) at the last follow-up. Stem revision was required in two cases. The MODULUS stem showed good long-term clinical and radiographic results, with a Kaplan-Meier survivorship of 97.6% (95% CI: 94.8-100.0%) at 8 years. PMID:25980775

  13. Process optimized minimally invasive total hip replacement.

    PubMed

    Gebel, Philipp; Oszwald, Markus; Ishaque, Bernd; Ahmed, Gaffar; Blessing, Recha; Thorey, Fritz; Ottersbach, Andreas

    2012-01-01

    The purpose of this study was to analyse a new concept of using the the minimally invasive direct anterior approach (DAA) in total hip replacement (THR) in combination with the leg positioner (Rotex- Table) and a modified retractor system (Condor). We evaluated retrospectively the first 100 primary THR operated with the new concept between 2009 and 2010, regarding operation data, radiological and clinical outcome (HOOS). All surgeries were perfomed in a standardized operation technique including navigation. The average age of the patients was 68 years (37 to 92 years), with a mean BMI of 26.5 (17 to 43). The mean time of surgery was 80 min. (55 to 130 min). The blood loss showed an average of 511.5 mL (200 to 1000 mL). No intra-operative complications occurred. The postoperative complication rate was 6%. The HOOS increased from 43 points pre-operatively to 90 (max 100 points) 3 months after surgery. The radiological analysis showed an average cup inclination of 43° and a leg length discrepancy in a range of +/- 5 mm in 99%. The presented technique led to excellent clinic results, showed low complication rates and allowed correct implant positions although manpower was saved. PMID:22577504

  14. Cement applicator use for hip resurfacing arthroplasty.

    PubMed

    Jaeger, Sebastian; Rieger, Johannes S; Obermeyer, Beate; Klotz, Matthias C; Kretzer, J Philippe; Bitsch, Rudi G

    2015-05-01

    We compared the manufacturer recommended cementing technique for a femoral hip resurfacing implant (BHR, S&N) to a newly designed cement applicator on 20 porous carbon foam specimens. Substantial design changes and improvements of the cement applicator were necessary: The diameter and number of the cement escaping holes at the top of the applicator were optimized for medium viscosity cement. It was necessary to add four separate air inlet holes with large diameters. The inner shape of the applicator had to be adapted to the BHR design with a circular extending chamfer in the proximal region, a parallel inner wall and a second chamfer distally. The interface temperatures showed no risk for heat necrosis using both techniques. The cement penetration depth was more uniform and significantly reduced for the applicator cementing technique (4.341.42mm, 6.420.43 mm, p=0.001). The cement-applicator showed no cement defects compared to a large defect length (0.00.0 mm, 10.361.10 mm, p<0.001) with the manufacturer recommended cementing technique. The cement applicator technique appears to be effective for a homogenous cement distribution without cement defects and safe with a lower risk of polar over-penetration. PMID:25772262

  15. Acetabular blood flow during total hip arthroplasty

    PubMed Central

    ElMaraghy, Amr W.; Schemitsch, Emil H.; Waddell, James P.

    2000-01-01

    Objective To determine the immediate effect of reaming and insertion of the acetabular component with and without cement on periacetabular blood flow during primary total hip arthroplasty (THA). Design A clinical experimental study. Setting A tertiary referral and teaching hospital in Toronto. Patients Sixteen patients (9 men, 7 women) ranging in age from 30 to 78 years and suffering from arthritis. Intervention Elective primary THA with a cemented (8 patients) and noncemented (8 patients) acetabular component. All procedures were done by a single surgeon who used a posterior approach. Main outcome measure Acetabular bone blood-flow measurements made with a laser Doppler flowmeter before reaming, after reaming and after insertion of the acetabular prosthesis. Results Acetabular blood flow after prosthesis insertion was decreased by 52% in the noncemented group (p < 0.001) and 59% in the cemented group (p < 0.001) compared with baseline (prereaming) values. Conclusion The significance of these changes in periacetabular bone blood flow during THA may relate to the extent of bony ingrowth, periprosthetic remodelling and ultimately the incidence of implant failure because of aseptic loosening. PMID:10851413

  16. Ion implantation and laser annealing

    NASA Astrophysics Data System (ADS)

    Three ion implantation and laser annealing projects have been performed by ORNL through the DOE sponsored Seed Money Program. The research has contributed toward improving the characteristics of wear, hardness, and corrosion resistance of some metals and ceramics, as well as the electrical properties of semiconductors. The work has helped to spawn related research, at ORNL and elsewhere, concerning the relationships between microstructure and materials properties. ORNL research has resulted in major advances in extended life and non-corrosive artificial joints (hip and knee), high performance semiconductors, failure resistant ceramics (with potential energy applications), and solar cells. The success of the seed money projects was instrumental in the formation of ORNL's Surface Modification and Characterization Facility (SMAC). More than 60 universities and companies have participated in SMAC programs.

  17. Near-infrared fluorescence imaging platform for quantifying in vivo nanoparticle diffusion from drug loaded implants

    PubMed Central

    Markovic, Stacey; Belz, Jodi; Kumar, Rajiv; Cormack, Robert A; Sridhar, Srinivas; Niedre, Mark

    2016-01-01

    Drug loaded implants are a new, versatile technology platform to deliver a localized payload of drugs for various disease models. One example is the implantable nanoplatform for chemo-radiation therapy where inert brachytherapy spacers are replaced by spacers doped with nanoparticles (NPs) loaded with chemotherapeutics and placed directly at the disease site for long-term localized drug delivery. However, it is difficult to directly validate and optimize the diffusion of these doped NPs in in vivo systems. To better study this drug release and diffusion, we developed a custom macroscopic fluorescence imaging system to visualize and quantify fluorescent NP diffusion from spacers in vivo. To validate the platform, we studied the release of free fluorophores, and 30 nm and 200 nm NPs conjugated with the same fluorophores as a model drug, in agar gel phantoms in vitro and in mice in vivo. Our data verified that the diffusion volume was NP size-dependent in all cases. Our near-infrared imaging system provides a method by which NP diffusion from implantable nanoplatform for chemo-radiation therapy spacers can be systematically optimized (eg, particle size or charge) thereby improving treatment efficacy of the platform. PMID:27069363

  18. Near-infrared fluorescence imaging platform for quantifying in vivo nanoparticle diffusion from drug loaded implants.

    PubMed

    Markovic, Stacey; Belz, Jodi; Kumar, Rajiv; Cormack, Robert A; Sridhar, Srinivas; Niedre, Mark

    2016-01-01

    Drug loaded implants are a new, versatile technology platform to deliver a localized payload of drugs for various disease models. One example is the implantable nanoplatform for chemo-radiation therapy where inert brachytherapy spacers are replaced by spacers doped with nanoparticles (NPs) loaded with chemotherapeutics and placed directly at the disease site for long-term localized drug delivery. However, it is difficult to directly validate and optimize the diffusion of these doped NPs in in vivo systems. To better study this drug release and diffusion, we developed a custom macroscopic fluorescence imaging system to visualize and quantify fluorescent NP diffusion from spacers in vivo. To validate the platform, we studied the release of free fluorophores, and 30 nm and 200 nm NPs conjugated with the same fluorophores as a model drug, in agar gel phantoms in vitro and in mice in vivo. Our data verified that the diffusion volume was NP size-dependent in all cases. Our near-infrared imaging system provides a method by which NP diffusion from implantable nanoplatform for chemo-radiation therapy spacers can be systematically optimized (eg, particle size or charge) thereby improving treatment efficacy of the platform. PMID:27069363

  19. Intraoperative Fluoroscopy Improves Component Position During Anterior Hip Arthroplasty.

    PubMed

    Jennings, John D; Iorio, Justin; Kleiner, Matthew T; Gaughan, John P; Star, Andrew M

    2015-11-01

    The goal of this retrospective review was to determine whether fluoroscopic guidance improves acetabular cup abduction and anteversion alignment during anterior total hip arthroplasty. The authors retrospectively reviewed 199 patients (fluoroscopy group, 98; nonfluoroscopy group, 101) who underwent anterior total hip arthroplasty at a single center with and without C-arm fluoroscopy guidance. Included in the study were patients of any age who underwent primary anterior approach total hip arthroplasty performed by a single surgeon, with 6-month postoperative anteroposterior pelvis radiographs. Acetabular cup abduction and anteversion angles were measured and compared between groups. Mean acetabular cup abduction and anteversion angles were 43.4° (range, 26.0°-57.4°) and 23.1° (range, 17°-28°), respectively, in the fluoroscopy group. Mean abduction and anteversion angles were 45.9° (range, 29.7°-61.3°) and 23.1° (range, 17°-28°), respectively, after anterior total hip arthroplasty without the use of C-arm guidance (nonfluoroscopy group). The use of fluoroscopy was associated with a statistically significant difference in cup abduction (P=.002) but no statistically significant difference in anteversion angles. In the fluoroscopy group, 80% of implants were within the combined safe zone compared with 63% in the nonfluoroscopy group. A significantly higher percentage of both acetabular cup abduction angles and combined anteversion and abduction angles were in the safe zone in the fluoroscopy group. Fluoroscopy is not required for proper anteversion placement of acetabular components, but it may increase ideal safe zone placement of components. PMID:26558676

  20. Contact pressures in the human hip joint measured in vivo.

    PubMed Central

    Hodge, W A; Fijan, R S; Carlson, K L; Burgess, R G; Harris, W H; Mann, R W

    1986-01-01

    The pressures on human articular cartilage have been measured in vivo. An instrumented femoral head prosthesis that telemeters interarticular pressure at 10 discrete locations 253 times per second was implanted in apposition to natural acetabular cartilage. Data were acquired during surgery, recovery, rehabilitation, and normal activity, for longer than 1 year after surgery. Pressure magnitudes were synchronized with body-segment kinematic data and foot-floor force measurements so as to locate transduced pressure areas on the natural acetabulum and correlate movement kinematics and dynamics with local cartilage pressures. The data reveal very high local (up to 18 MPa) and nonuniform pressures, with abrupt spatial and temporal gradients, that correlate well both in magnitude and distribution with in vitro data and computer simulations of synovial joint mechanics. Peak pressures in vivo are, however, considerably higher than pressures measured in vitro under the putative forces experienced by the joint in life, particularly in normal movements where cocontraction occurs in agonist and antagonist muscles across the hip joint. Thus, extant gait-analysis studies which apply inverse Newtonian calculations to infer joint forces establish the lower limit on such forces, since such analyses include only the net muscular torques about the joint and cannot account for the contribution of the increment in joint force due to muscular cocontraction. Our data also contribute to the understanding of normal synovial joint tribology and the possible role of mechanical factors in the deterioration evident in osteoarthritis. Further, design criteria for both partial and total hip replacement prostheses and specific aspects of rehabilitation protocols following hip surgery (e.g., the extent to which crutches and canes unload the hip joint) warrant reconsideration in light of the extraordinary high pressures measured during the activities of daily living. Images PMID:3458248

  1. Molecular Mechanisms of HipA Mediated Multidrug Tolerance and its Neutralization by HipB

    PubMed Central

    Schumacher, Maria A.; Piro, Kevin M.; Xu, Weijun; Hansen, Sonja; Lewis, Kim; Brennan, Richard G.

    2009-01-01

    Summary Bacterial multidrug tolerance is largely responsible for the inability of antibiotics to eradicate infections and is caused by a small population of dormant bacteria called persisters. HipA is a critical Escherichia coli persistence factor that is normally neutralized by HipB, a transcription repressor, which also regulates hipBA expression. Here we report multiple structures of HipA and a HipA-HipB-DNA complex. HipA has a eukaryotic Ser/Thr kinase-like fold and can phosphorylate the translation factor, EF-Tu, suggesting a persistence mechanism via cell stasis. The HipA-HipB-DNA structure reveals the HipB-operator binding mechanism, ~70° DNA bending and unexpected HipA-DNA contacts. Dimeric HipB interacts with two HipA molecules to inhibit its kinase activity through sequestration and conformational inactivation. Combined, these studies suggest mechanisms for HipA-mediated persistence and its neutralization by HipB. PMID:19150849

  2. Aggregation behavior of a gemini surfactant with a tripeptide spacer.

    PubMed

    Wang, Meina; Han, Yuchun; Qiao, Fulin; Wang, Yilin

    2015-02-28

    A peptide gemini surfactant, 12-G(NH2)LG(NH2)-12, has been constructed with two dodecyl chains separately attached to the two terminals of a glutamic acid-lysine-glutamic acid peptide and the aggregation behavior of the surfactant was studied in aqueous solution. The 12-G(NH2)LG(NH2)-12 molecules form fiber-like precipitates around pH 7.0, and the precipitation range is widened on increasing the concentration. At pHs 3.0 and 11.0, 12-G(NH2)LG(NH2)-12 forms soluble aggregates because each molecule carries two positively charged amino groups at the two ends of the peptide spacer at pH 3.0, while each molecule carries one negatively charged carboxyl group in the middle of the peptide spacer at pH 11.0. 12-G(NH2)LG(NH2)-12 displays a similar concentration-dependent process at these two pHs: forming small micelles above the critical micelle concentration and transferring to fibers at pH 3.0 or twisted ribbons at pH 11.0 above the second critical concentration. The fibers formed at pH 3.0 tend to aggregate into bundles with twisted structure. Both the twisted fibers at pH 3.0 and the twisted ribbons at pH 11.0 contain β-sheet structure formed by the peptide spacer. PMID:25588349

  3. Bringing aptamers into technologies: Impact of spacer terminations

    NASA Astrophysics Data System (ADS)

    Brut, M.; Trapaidze, A.; Estève, A.; Bancaud, A.; Estève, D.; Landa, G.; Djafari-Rouhani, M.

    2012-04-01

    We propose a low cost modeling approach to screen the impact of aptamer structural modifications on their biomechanical stability. This responds to the current immature control of aptamer properties when integrated into bio-hybrid devices. We predict that common spacers (PEG, polythymine) disrupt aptamer rigidity, whereas alkyl chains have minimal incidence on its mechanical properties. We also observe that mutations in the active site are equally perturbative as PEG or polythymine. We suggest that the rational design of aptamer-based biosensing devices calls for a precise modeling of surface grafting and envision that our tool is readily adapted to face this challenge.

  4. Possibility of one-stage surgery to reconstruct bone defects using the modified Masquelet technique with degradable calcium sulfate as a cement spacer: A case report and hypothesis

    PubMed Central

    JIANG, NAN; QIN, CHENG-HE; MA, YUN-FEI; WANG, LEI; YU, BIN

    2016-01-01

    In addition to autologous bone graft, vascularized fibular autograft and Ilizarov bone transfer, the Masquelet technique is another effective method to reconstruct bone defects. This technique was initially proposed in 1986 and consists of two stages. At the first stage, radical debridement is required and subsequently, a polymethylmethacrylate (PMMA) cement spacer is implanted at the site of the bone defects. At the second stage, when the PMMA-induced membrane is formed 6–8 weeks later, the cement spacer is carefully removed in order to not disturb the induced membrane and the bone graft is performed to fill the bone defects. Although this technique has resulted in satisfactory outcomes in the reconstruction of bone defects, the PMMA spacer used to induce membrane is not degradable and requires surgical removal. In recent years, calcium sulfate has been used as a localized antibiotic delivery vehicle and bone substitute due to its superiorities over PMMA, particularly its completely degradable nature. The present study identified that calcium sulfate can also induce the formation of a membrane. In addition, we hypothesized that the degradability of calcium sulfate may allow one-stage reconstruction of bone defects. The current study presents a clinical case report and review of the literature. PMID:26998279

  5. Simulation of Anti-Galloping Effects of Phase-to-Phase Spacers in Transmission Line

    NASA Astrophysics Data System (ADS)

    Liu, Chao-Qun; Chen, Hua-Ling; Liu, Bin; Liu, Cao-Lan; Sun, Na; Yang, Jia-Lun

    Currently, the application of phase-to-phase spacers can effectively prevent and control line faults caused by conductor galloping and is one of the most effective methods to prevent galloping of transmission lines. The installation layout scheme of phase-to-phase spacers directly affects the anti-galloping effect. Moreover, the common empirical formula can not accurately assess the anti-galloping effect of phase-to-phase spacers. In this paper, the nonlinear finite element method is employed to establish an accurate analysis model of phase-to-phase spacers for conductors. And the anti-galloping effects of phase-to-phase spacers installed in different ways are analyzed, with the aim of providing an effective method for the installation of phase-to-phase spacers used in practical transmission lines.

  6. Supercapsular percutaneously-assisted total hip arthroplasty: radiographic outcomes and surgical technique

    PubMed Central

    Della Torre, Paul K.; Fitch, David A.

    2015-01-01

    Background The supercapsular percutaneously-assisted total hip (SuperPATH®) approach for total hip arthroplasty (THA) was developed to promote early mobilization and greater range of motion, physiologic gait kinematics and improved pain control. The superpath approach is a hybrid of the Superior Capsulotomy (SuperCap®) approach and the percutaneously assisted total hip (PATH®) technique. Methods Postoperative radiographs of 66 consecutive patients from the first 100 patients who underwent the SuperPATH approach were analysed by an independent third party for component position and seating, femoral offset and leg length. A detailed description of preoperative and postoperative preparation, soft tissue dissection, preparation of the femoral canal and acetabulum, and implant positioning is also provided with figures to illustrate. Results All components in this case series were well seated and position deemed optimal. Leg lengths were measured to within 5 mm of the contralateral side and mean acetabular abduction angle was 40.13° (SD 6.30°). Conclusions Through preservation of the external rotators, hip capsule, and abductor integrity, the SuperPATH approach for THA maximally preserves the surrounding soft tissue envelope. Implant position was optimal within the ‘learning curve’ of the first 100 cases for described THA safe zones. Long term outcome data for the SuperPATH approach are being collected as part of an ongoing study to compare to favourable short and mid-term results. PMID:26366397

  7. How Do Metal Ion Levels Change over Time in Hip Resurfacing Patients? A Cohort Study

    PubMed Central

    Savarino, Lucia; Cadossi, Matteo; Chiarello, Eugenio; Fotia, Caterina; Greco, Michelina; Baldini, Nicola; Giannini, Sandro

    2014-01-01

    Metal-on-metal hip resurfacing (MOM-HR) is offered as an alternative to traditional hip arthroplasty for young, active adults with advanced osteoarthritis. Nevertheless, concerns remain regarding wear and corrosion of the bearing surfaces and the resulting increase in metal ion levels. We evaluated three cohorts of patients with Birmingham hip resurfacing (BHR) at an average follow-up of 2, 5, and 9 years. We asked whether there would be differences in ion levels between the cohorts and inside the gender. Nineteen patients were prospectively analyzed. The correlation with clinical-radiographic data was also performed. Chromium, cobalt, nickel, and molybdenum concentrations were measured by atomic absorption spectrophotometry. Chromium and cobalt levels demonstrated a tendency to decrease over time. Such tendency was present only in females. An inverse correlation between chromium, implant size, and Harris hip score was present at short term; it disappeared over time together with the decreased ion levels. The prospective analysis showed that, although metal ion levels remained fairly constant within each patient, there was a relatively large variation between subjects, so mean data in this scenario must be interpreted with caution. The chronic high exposure should be carefully considered during implant selection, particularly in young subjects, and a stricter monitoring is mandatory. PMID:25580456

  8. How do metal ion levels change over time in hip resurfacing patients? A cohort study.

    PubMed

    Savarino, Lucia; Cadossi, Matteo; Chiarello, Eugenio; Fotia, Caterina; Greco, Michelina; Baldini, Nicola; Giannini, Sandro

    2014-01-01

    Metal-on-metal hip resurfacing (MOM-HR) is offered as an alternative to traditional hip arthroplasty for young, active adults with advanced osteoarthritis. Nevertheless, concerns remain regarding wear and corrosion of the bearing surfaces and the resulting increase in metal ion levels. We evaluated three cohorts of patients with Birmingham hip resurfacing (BHR) at an average follow-up of 2, 5, and 9 years. We asked whether there would be differences in ion levels between the cohorts and inside the gender. Nineteen patients were prospectively analyzed. The correlation with clinical-radiographic data was also performed. Chromium, cobalt, nickel, and molybdenum concentrations were measured by atomic absorption spectrophotometry. Chromium and cobalt levels demonstrated a tendency to decrease over time. Such tendency was present only in females. An inverse correlation between chromium, implant size, and Harris hip score was present at short term; it disappeared over time together with the decreased ion levels. The prospective analysis showed that, although metal ion levels remained fairly constant within each patient, there was a relatively large variation between subjects, so mean data in this scenario must be interpreted with caution. The chronic high exposure should be carefully considered during implant selection, particularly in young subjects, and a stricter monitoring is mandatory. PMID:25580456

  9. The clinical and radiological outcomes of hip resurfacing versus total hip arthroplasty: a meta-analysis and systematic review

    PubMed Central

    2010-01-01

    Background and purpose Hip resurfacing (HRS) procedures have gained increasing popularity for younger, higher-demand patients with degenerative hip pathologies. However, with concerns regarding revision rates and possible adverse metal hypersensitivity reactions with metal-on-metal articulations, some authors have questioned the hypothesized superiority of hip resurfacing over total hip arthroplasty (THA). In this meta-analysis, we compared the clinical and radiological outcomes and complication rates of these 2 procedures. Methods A systematic review was undertaken of all published (Medline, CINAHL, AMED, EMBASE) and unpublished or gray literature research databases up to January 2010. Clinical and radiological outcomes as well as complications of HRS were compared to those of THA using risk ratio, mean difference, and standardized mean difference statistics. Studies were critically appraised using the CASP appraisal tool. Results 46 studies were identified from 1,124 citations. These included 3,799 HRSs and 3,282 THAs. On meta-analysis, functional outcomes for subjects following HRS were better than or the same as for subjects with a THA, but there were statistically significantly greater incidences of heterotopic ossification, aseptic loosening, and revision surgery with HRS compared to THA. The evidence base showed a number of methodological inadequacies such as the limited use of power calculations and poor or absent blinding of both patients and assessors, possibly giving rise to assessor bias. Interpretation On the basis of the current evidence base, HRS may have better functional outcomes than THA, but the increased risks of heterotopic ossification, aseptic loosening, and revision surgery following HRS indicate that THA is superior in terms of implant survival. PMID:21067432

  10. Hip-Hop Pop Art

    ERIC Educational Resources Information Center

    Talley, Clarence, Sr.

    2011-01-01

    Art has a way of helping students better understand and appreciate the world around them, particularly the things that are most important to them. Hip hop is one of those generational genres that capture the attention of young students like few other things do. Drawing on this genre to get students to create art is an excellent way to demonstrate…

  11. Hip: Anatomy and US technique.

    PubMed

    Molini, L; Precerutti, M; Gervasio, A; Draghi, F; Bianchi, S

    2011-06-01

    Ultrasound (US) has always had a relatively limited role in the evaluation of the hip due to the deep location of this joint. However, many hip diseases are well detectable at US, but before approaching such a study it is necessary to be thoroughly familiar with the normal anatomy and related US images. The study technique is particularly important as optimization of various parameters is required, such as probe frequency, focalization, positioning of the probe, etc. Also the patient's position is important, as it varies according to the area requiring examination. For the study of the anterior structures, the patient should be in the supine position; for the medial structures, the leg should be abducted and rotated outward with the knee flexed; for the lateral structures, the patient should be in the controlateral decubitus position; for the posterior structures the patient must be in the prone position. US study of the hip includes assessment of the soft tissues, tendons, ligaments and muscles, and also of the bone structures, joint space and serous bursae. The purpose of this article is to review the normal anatomy of the hip as well as the US anatomy of this joint. PMID:23397030

  12. Hip-Hop Pop Art

    ERIC Educational Resources Information Center

    Talley, Clarence, Sr.

    2011-01-01

    Art has a way of helping students better understand and appreciate the world around them, particularly the things that are most important to them. Hip hop is one of those generational genres that capture the attention of young students like few other things do. Drawing on this genre to get students to create art is an excellent way to demonstrate

  13. Evaluation of a bioglass-coated Al2O3 total hip prosthesis in sheep.

    PubMed

    Griss, P; Greenspan, D C; Heimke, G; Krempien, B; Buchinger, R; Hench, L L; Jentschura, G

    1976-07-01

    A bioglass-coated fully dense alumina total hip was evaluated in sheep without using polymer bone "cement." After 3 months following surgery, both the acetabular cup and femoral stem component were firmly attached to bone. Histologic and radiographic analysis of the bone-implant interface showed regions of woven and even lamellar bone formation where high load transmission occurred. In regions of low loading or poor fit, a pseudosynovial fibrous lining was present. PMID:947914

  14. Digital templating facilitates accurate leg length correction in total hip arthroplasty.

    PubMed

    Jassim, Shivan Sabah; Ingham, Christopher; Keeling, Matthew; Wimhurst, James Anthony

    2012-06-01

    Digital templating of pre-operative radiographs is increasingly utilised by surgeons before total hip arthroplasty (THA) as part of an adequate preoperative preparation to minimise complications. Templating can accurately predict the required implant sizes but its use in facilitating correction of leg length discrepancy (LLD) has been underreported in the literature. We performed a retrospective analysis of a cohort of consecutive patients undergoing primary THA. A comparison was made of the implant sizes templated with actual sizes used. In addition, pre-operative leg-length discrepancy (LLD) was noted and compared with intra-operative measurement of LLD correction and post-operative LLD correction seen on postoperative radiographs, as measured by two independent observers. Statistical analysis was performed to investigate the correlation between pre- and postoperative measurements. Fifty nine patients that had primary THA were investigated, 42 with hybrid replacements, 17 with cemented replacements. Spearman's-rho 2-tailed correlation between templated and implanted femoral offset, stem size and acetabular cup size was 0.850, 0.709 and 0.834 respectively (p < 0.01 for all). Correlation between the pre-operative templated LLD and the measured post-operative corrected LLD was 0.841 (p < 0.01). No difference existed between hybrid and cemented hips or the presence or absence of a contralateral hip replacement. In this study, templating for THA was significantly accurate in predicting the required femoral and acetabular implant sizes. In addition, the correction of pre-operative LLD was accurately performed, as evidenced by measurement on post-operative films. The results of this study support the pre-operative digital templating of radiographs in total hip arthroplasty. PMID:22822575

  15. Expandable Polyaryl-Ether-Ether-Ketone Spacers for Interbody Distraction in the Lumbar Spine

    PubMed Central

    Alimi, Marjan; Shin, Benjamin; Macielak, Michael; Hofstetter, Christoph P.; Njoku, Innocent; Tsiouris, Apostolos J.; Elowitz, Eric; Härtl, Roger

    2015-01-01

    Study Design Retrospective case series. Objective StaXx XD (Spine Wave, Inc., Shelton, CT, United States) is an expandable polyaryl-ether-ether-ketone (PEEK) wafer implant utilized in the treatment of lumbar degenerative disease. PEEK implants have been successfully used as interbody devices. Few studies have focused on expandable PEEK devices. The aim of the current study is to determine the radiographic and clinical outcome of expandable PEEK cages utilized for transforaminal lumbar interbody fusion in patients with lumbar degenerative diseases. Methods Forty-nine patients who underwent lumbar interbody fusion with implantation of expandable PEEK cages and posterior instrumentation were included. The clinical outcome was evaluated using the visual analog scale (VAS) and the Oswestry Disability Index (ODI). Radiographic parameters including disk height, foraminal height, listhesis, local disk angle of the index level/levels, regional lumbar lordosis, and graft subsidence were measured preoperatively, postoperatively, and at latest follow-up. Results At an average follow-up of 19.3 months, the minimum clinically important difference for the ODI and VAS back, buttock, and leg were achieved in 64, 52, 58, and 52% of the patients, respectively. There was statistically significant improvement in VAS back (6.42 versus 3.11, p < 0.001), VAS buttock (4.66 versus 1.97, p = 0.002), VAS leg (4.55 versus 1.96, p < 0.001), and ODI (21.7 versus 12.1, p < 0.001) scores. There was a significant increase in the average disk height (6.49 versus 8.18 mm, p = 0.037) and foraminal height (15.6 versus 18.53 mm, p = 0.0001), and a significant reduction in the listhesis (5.13 versus 3.15 mm, p = 0.005). The subsidence of 0.66 mm (7.4%) observed at the latest follow-up was not significant (p = 0.35). Conclusions Midterm results indicate that expandable PEEK spacers can effectively and durably restore disk and foraminal height and improve the outcome without significant subsidence. PMID:26131383

  16. Expandable Polyaryl-Ether-Ether-Ketone Spacers for Interbody Distraction in the Lumbar Spine.

    PubMed

    Alimi, Marjan; Shin, Benjamin; Macielak, Michael; Hofstetter, Christoph P; Njoku, Innocent; Tsiouris, Apostolos J; Elowitz, Eric; Härtl, Roger

    2015-06-01

    Study Design Retrospective case series. Objective StaXx XD (Spine Wave, Inc., Shelton, CT, United States) is an expandable polyaryl-ether-ether-ketone (PEEK) wafer implant utilized in the treatment of lumbar degenerative disease. PEEK implants have been successfully used as interbody devices. Few studies have focused on expandable PEEK devices. The aim of the current study is to determine the radiographic and clinical outcome of expandable PEEK cages utilized for transforaminal lumbar interbody fusion in patients with lumbar degenerative diseases. Methods Forty-nine patients who underwent lumbar interbody fusion with implantation of expandable PEEK cages and posterior instrumentation were included. The clinical outcome was evaluated using the visual analog scale (VAS) and the Oswestry Disability Index (ODI). Radiographic parameters including disk height, foraminal height, listhesis, local disk angle of the index level/levels, regional lumbar lordosis, and graft subsidence were measured preoperatively, postoperatively, and at latest follow-up. Results At an average follow-up of 19.3 months, the minimum clinically important difference for the ODI and VAS back, buttock, and leg were achieved in 64, 52, 58, and 52% of the patients, respectively. There was statistically significant improvement in VAS back (6.42 versus 3.11, p < 0.001), VAS buttock (4.66 versus 1.97, p = 0.002), VAS leg (4.55 versus 1.96, p < 0.001), and ODI (21.7 versus 12.1, p < 0.001) scores. There was a significant increase in the average disk height (6.49 versus 8.18 mm, p = 0.037) and foraminal height (15.6 versus 18.53 mm, p = 0.0001), and a significant reduction in the listhesis (5.13 versus 3.15 mm, p = 0.005). The subsidence of 0.66 mm (7.4%) observed at the latest follow-up was not significant (p = 0.35). Conclusions Midterm results indicate that expandable PEEK spacers can effectively and durably restore disk and foraminal height and improve the outcome without significant subsidence. PMID:26131383

  17. Techniques and Results for Open Hip Preservation

    PubMed Central

    Levy, David M.; Hellman, Michael D.; Haughom, Bryan; Stover, Michael D.; Nho, Shane J.

    2015-01-01

    While hip arthroscopy grows in popularity, there are still many circumstances under which open hip preservation is the most appropriately indicated. This article specifically reviews open hip preservation procedures for a variety of hip conditions. Femoral acetabular impingement may be corrected using an open surgical hip dislocation. Acetabular dysplasia may be corrected using a periacetabular osteotomy. Acetabular protrusio may require surgical hip dislocation with rim trimming and a possible valgus intertrochanteric osteotomy. Legg–Calve–Perthes disease produces complex deformities that may be better served with osteotomies of the proximal femur and/or acetabulum. Chronic slipped capital femoral epiphysis may also benefit from a surgical hip dislocation and/or proximal femoral osteotomy. PMID:26649292

  18. Reproduction of Hip Offset and Leg Length in Navigated Total Hip Arthroplasty: How Accurate Are We?

    PubMed

    Ellapparadja, Pregash; Mahajan, Vivek; Deakin, Angela H; Deep, Kamal

    2015-06-01

    This study assesses how accurately we can restore hip offset and leg length in navigated total hip arthroplasty (THA). 152 consecutive patients with navigated THA formed the study group. The contra-lateral hip formed control for measuring hip offset and leg length. All radiological measurements were made using Orthoview digital software. In the normal hip offset group, the mean is 75.73 (SD- 8.61). In the reconstructed hip offset group, the mean is 75.35 (SD - 7.48). 95.39% had hip offset within 6 mm of opposite side while 96.04% had leg length restored within 6 mm of contra-lateral side. Equivalence test revealed that the two groups of hip offsets were essentially the same. We conclude that computer navigation can successfully reproduce hip offset and leg length accurately. PMID:25677938

  19. Frontal plane kinematics of the hip during running: Are they related to hip anatomy and strength?

    PubMed

    Baggaley, Michael; Noehren, Brian; Clasey, Jody L; Shapiro, Robert; Pohl, Michael B

    2015-10-01

    Excessive hip adduction has been associated with a number of lower extremity overuse running injuries. The excessive motion has been suggested to be the result of reduced strength of the hip abductor musculature. Hip anatomical alignment has been postulated to influence hip abduction (HABD) strength and thus may impact hip adduction during running. The purpose of this study was to investigate the relationship between hip anatomy, HABD strength, and frontal plane kinematics during running. Peak isometric HABD strength, 3D lower extremity kinematics during running, femoral neck-shaft angle (NSA), and pelvis width-femur length (PW-FL) ratio were recorded for 25 female subjects. Pearson correlations (p<0.05) were performed between variables. A fair relationship was observed between femoral NSA and HABD strength (r=-0.47, p=0.02) where an increased NSA was associated with reduced HABD strength. No relationship was observed between HABD strength and hip adduction during running. None of the anatomical measurements, NSA or PW-FL, were associated with hip adduction during running. Deviations in the femoral NSA have a limited ability to influence peak isometric hip abduction strength or frontal plane hip kinematics during running. Hip abduction strength does also not appear to be linked with changes in hip kinematics. These findings in healthy individuals question whether excessive hip adduction typically seen in female runners with overuse injuries is caused by deviations in hip abduction strength or anatomical structure. PMID:26364243

  20. Microscopical analysis of synovial fluid wear debris from failing CoCr hip prostheses

    NASA Astrophysics Data System (ADS)

    Ward, M. B.; Brown, A. P.; Cox, A.; Curry, A.; Denton, J.

    2010-07-01

    Metal on metal hip joint prostheses are now commonly implanted in patients with hip problems. Although hip replacements largely go ahead problem free, some complications can arise such as infection immediately after surgery and aseptic necrosis caused by vascular complications due to surgery. A recent observation that has been made at Manchester is that some Cobalt Chromium (CoCr) implants are causing chronic pain, with the source being as yet unidentified. This form of replacement failure is independent of surgeon or hospital and so some underlying body/implant interface process is thought to be the problem. When the synovial fluid from a failed joint is examined particles of metal (wear debris) can be found. Transmission Electron Microscopy (TEM) has been used to look at fixed and sectioned samples of the synovial fluid and this has identified fine (< 100 nm) metal and metal oxide particles within the fluid. TEM EDX and Electron Energy Loss Spectroscopy (EELS) have been employed to examine the composition of the particles, showing them to be chromium rich. This gives rise to concern that the failure mechanism may be associated with the debris.

  1. High Re-Operation Rates Using Conserve Metal-On-Metal Total Hip Articulations

    PubMed Central

    Mogensen, S.L.; Jakobsen, T.; Christoffersen, H.; Krarup, N.

    2016-01-01

    Introduction: Metal-on-metal hip articulations have been intensely debated after reports of adverse reactions and high failure rates. The aim of this study was to retrospectively evaluate the implant of a metal-on.metal total hip articulation (MOM THA) from a single manufacture in a two-center study. Materials and Methods: 108 CONSERVE® MOM THA were implanted in 92 patients between November 2005 and December 2010. Patients had at time of retrospective evaluation their journals reviewed for re-operations and adverse reactions. Results: 20 hips were re-operated (18.4%) at a mean follow up of 53 months. 4 pseudotumors were diagnosed at time of follow up but no substantiated link was made between adverse reactions and re-operations. Conclusion: The high re-operation rates found in this study raised concern about the usage of the MOM THA and subsequently lead to the termination of implantation of this MOM THA at the two orthopaedic departments. PMID:27099640

  2. Corrosion of the Head-neck Junction After Total Hip Arthroplasty.

    PubMed

    Jennings, Jason M; Dennis, Douglas A; Yang, Charlie C

    2016-06-01

    Corrosion of the head-neck junction of implants used in total hip arthroplasty is a complex problem. Clinical severity appears to be multifactorial, and the predictive variables have yet to be consistently identified in the literature. Corrosion should be considered in the differential diagnosis of hip pain following total hip arthroplasty regardless of the type of bearing surface used. The most common presentation, pain followed by instability, is similar to complications associated with metal-on-metal articulations. The diagnosis of implant corrosion of the head-neck junction can be challenging; an infection workup should be performed along with analysis of serum metal ion levels and cross-sectional imaging. In the short term, a well-fixed stem may be retained, and the exchange of an isolated head with a ceramic femoral head seems to be a promising option for certain implants. Further research with longer follow-up is warranted, and high levels of evidence are needed to determine whether this approach is generalizable. PMID:27213620

  3. Dislocation of a dual mobility total hip replacement following fracture of the polyethylene liner.

    PubMed

    Vedrine, Bertrand; Guillaumot, Pierre; Chancrin, Jean-Luc

    2016-05-18

    An eight-year-old male English Setter was referred for management of a dislocation of a cemented dual mobility canine total hip prosthesis that occurred four months after the initial surgery. Revision surgery showed that the dislocation was associated with fracture of the ultra-high molecular weight polyethylene liner. The dislocation was successfully reduced after replacing the liner. A dual mobility acetabular component is composed of a mobile polyethylene liner inside a metallic cemented cup. Chronic wear of the components of a canine dual mobility total hip replacement has not been described previously. The use of this type of implant is fairly recent and limited long term follow-up of the implanted cases may be the explanation. Acute rupture of a polyethylene liner has never been described in humans, the only case of rupture of a polyethylene liner occurred 10 years after implantation. The case presented here of rupture of the polyethylene liner of a dual mobility total hip replacement is a hitherto unreported failure mode in this model of acetabular cup in the dog. PMID:26991949

  4. Packaging design criteria modified fuel spacer burial box. Revision 1

    SciTech Connect

    Stevens, P.F.

    1994-09-13

    Various Hanford facilities must transfer large radioactively contaminated items to burial/storage. Presently, there are eighteen Fuel Spacer Burial Boxes (FSBBs) available on the Hanford Site for transport of such items. Previously, the FSBBS were transported from a rail car to the burial trench via a drag-off operation. To allow for the lifting of the boxes into the burial trench, it will be necessary to improve the packagings lifting attachments and provide structural reinforcement. Additional safety improvements to the packaging system will be provided by the addition of a positive closure system and package ventilation. FSBBs that are modified in such a manner are referred to as Modified Fuel Spacer Burial Boxes (MFSBs). The criteria provided by this PDC will be used to demonstrate that the transfer of the MFSB will provide an equivalent degree of safety as would be provided by a package meeting offsite transportation requirements. This fulfills the onsite transportation safety requirements implemented in WHC-CM-2-14, Hazardous Material Packaging and Shipping. A Safety Analysis Report for Packaging (SARP) will be prepared to evaluate the safety of the transfer operation. Approval of the SARP is required to authorize transfer. Criteria are also established to ensure burial requirements are met.

  5. Simultaneous measurement of friction and wear in hip simulators.

    PubMed

    Haider, Hani; Weisenburger, Joel N; Garvin, Kevin L

    2016-05-01

    We propose and have evaluated a method to measure hip friction during wear testing on a popular multi-station hip simulator. A 6-degree-of-freedom load cell underneath the specimen sensed forces and torques during implant wear testing of simulated walking. This included internal-external and adduction-abduction rotations which are often neglected during friction testing on pendulum-type machines. Robust mathematical analysis and data processing provided friction estimates in three simultaneous orthogonal rotations, over extended multi-million cycle wear tests. We tested various bearing couples including metal-on-plastic, ceramic-on-plastic, and metal-on-metal material couples. In one test series, new and intentionally scratched CoCrMo 40-mm-diameter femoral heads were tested against conventional ultrahigh-molecular-weight polyethylene, highly cross-linked, and highly cross-linked with vitamin E versions. The scratching significantly increased friction and doubled the wear of all groups. Before scratching, friction levels for the aforementioned plastic groups were 0.056 ± 0.0060, 0.062 ± 0.0080, and 0.070 ± 0.0045, respectively, but after scratching increased to 0.088 ± 0.018, 0.076 ± 0.0066, and 0.082 ± 0.0049, respectively, all statistically significant increases (p = 0.00059, 0.00005, 0.0115, respectively). In another test series of 44-mm femoral head diameter hips, metal-on-plastic hips with conventional ultrahigh-molecular-weight polyethylene showed the lowest friction at 0.045 ± 0.0085, followed by highly cross-linked with 0.046 ± 0.0035 (not significantly different). In a ceramic-on-plastic design with conventional ultrahigh-molecular-weight polyethylene, higher friction 0.079 ± 0.0070 was measured likely due to that ceramic surface being rougher than usual. Metal-on-metal hips were compared without and with a TiN coating, resulting in 0.049 ± 0.014 and 0.097 ± 0.020 friction factors, respectively (statistically significant, p < 0.001), and the coating wore away on all coated hips eventually. Higher friction mostly correlated with higher wear or damage to femoral heads or implant coatings, except for the highly cross-linked wear resistant ultrahigh-molecular-weight polyethylene which had slightly higher friction, confirming the same finding in other independent studies. This type of friction measurements can help screen for clamping and elevated wear of metal-on-metal and resurfacing total hip replacements, surgical malpositioning, and abraded and otherwise damaged surfaces. PMID:27160558

  6. An analysis of the hip and knee reconstruction section of the orthopaedic in-training examination.

    PubMed

    Cross, Michael B; Osbahr, Daryl C; Nam, Denis; Reinhardt, Keith R; Bostrom, Mathias P G; Dines, Joshua S

    2011-09-01

    This article analyzes the hip and knee reconstruction section of the Orthopaedic In-Training Examination (OITE). All of the hip and knee reconstruction questions from 2005 to 2009 were analyzed, and the following data were recorded: number of questions per year in the hip and knee section, total number of questions on the OITE per year, national average score by year in training, references cited, taxonomy classification of each question, topics that were tested, imaging modalities used for a given question, and treatment modalities tested. Eight percent to 9% of the questions on the OITE each year were hip and knee reconstruction-related questions. Performance improved with each year in training, but not by a statistically significant amount. The most commonly tested topics over the past 5 years were anatomy and physiology, ligament and/or gap balancing during total knee arthroplasty (TKA), surgical approaches, properties of polyethylene, periprosthetic fractures about an arthroplasty, and questions dealing with the mechanical properties of implants. In 4 out of 5 years, the majority of questions were classified as Taxonomy 1 (knowledge and recall). The bulk of the questions each year did not require the examinee to interpret a radiograph or make a treatment decision. The most common references cited were from Journal of Bone and Joint Surgery (American), followed by the Journal of Arthroplasty. This detailed analysis of the hip and knee reconstruction section of the OITE should improve resident performance, and may serve as a study tool for the OITE. PMID:21902156

  7. The Exeter™ Universal Hip in Patients 50 Years or Younger at 10–17 Years’ Followup

    PubMed Central

    Squires, Ben; Gie, Graham A.; Timperley, Andrew J.; Ling, Robin S. M.

    2008-01-01

    The Exeter™ Universal hip (Stryker Inc., Newbury, UK) has reported survival rates of 91.74% at 12 years in all patients with reoperation as an endpoint. However, its performance in younger patients has not been fully established. We reviewed survivorship and the clinical and radiographic outcomes of this hip system implanted in 107 patients (130 hips) 50 years old or younger at the time of surgery. The mean age at surgery was 42 years. The minimum followup was 10 years (mean, 12.5 years; range, 10–17 years) with no patients lost to followup. Twelve hips had been revised. Of these, nine had aseptic loosening of the acetabular component and one cup was revised for focal lysis and pain. One hip was revised for recurrent dislocation and one joint underwent revision for infection. Radiographs demonstrated 14 (12.8%) of the remaining acetabular prostheses were loose but no femoral components were loose. Survivorship of both stem and cup from all causes was 92.6% at an average of 12.5 years. Survivorship of the stem from all causes was 99% and no stem was revised for aseptic loosening. The Exeter™ Universal stem performed well, even in the young, high-demand patient. Level of Evidence: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence. PMID:18196413

  8. Subtrochanteric Fracture following Removal of a Porous Tantalum Implant.

    PubMed

    Amanatullah, Derek F; Farac, Randall; McDonald, Thomas J; Moehring, H David; Di Cesare, Paul E

    2013-01-01

    Osteonecrosis of the hip accounts for about 10% of all total hip arthroplasty cases and presents a significant challenge for those patients with and without femoral head collapse. Subtrochanteric femur fractures have been reported with numerous types of proximal femoral implants. Care must be taken to avoid penetrating the lateral cortex of the proximal femur inferior to the distal border of the lesser trochanter. Core decompression requires a 3 mm to 20 mm defect in the lateral femoral cortex. Subtrochanteric femur fractures are a well-known complication of core decompression as well. We present a case of a subtrochanteric fracture following the removal of a porous tantalum implant. PMID:24367733

  9. Subtrochanteric Fracture following Removal of a Porous Tantalum Implant

    PubMed Central

    Amanatullah, Derek F.; McDonald, Thomas J.; Moehring, H. David; Di Cesare, Paul E.

    2013-01-01

    Osteonecrosis of the hip accounts for about 10% of all total hip arthroplasty cases and presents a significant challenge for those patients with and without femoral head collapse. Subtrochanteric femur fractures have been reported with numerous types of proximal femoral implants. Care must be taken to avoid penetrating the lateral cortex of the proximal femur inferior to the distal border of the lesser trochanter. Core decompression requires a 3 mm to 20 mm defect in the lateral femoral cortex. Subtrochanteric femur fractures are a well-known complication of core decompression as well. We present a case of a subtrochanteric fracture following the removal of a porous tantalum implant. PMID:24367733

  10. The chemical form of metallic debris in tissues surrounding metal-on-metal hips with unexplained failure.

    PubMed

    Hart, Alister J; Quinn, Paul D; Sampson, Barry; Sandison, Ann; Atkinson, Kirk D; Skinner, John A; Powell, Jonathan J; Mosselmans, J Fred W

    2010-11-01

    Implant-derived material from metal-on-metal (MOM) hip arthroplasties may be responsible for an unexplained tissue inflammatory response. The chemical form of the metal species in the tissues is predominantly chromium (Cr), but the currently used techniques have not been able to determine whether this is Cr(III) phosphate or Cr(III) oxide. The analytical challenge must overcome the fact that the metal in the tissues is at a relatively low concentration and tissue preparation or the microscopy beam used can affect the results. Microfocus X-ray spectroscopy using a synchrotron beam is useful in addressing both these issues. Using this technique we compared tissue from failed MOM hips with: (1) tissue from metal-on-polyethylene (MOP) hips; (2) chemical standards; (3) metal discs cut from MOM hips. The most abundant implant-related species in all MOM hip tissues contained Cr. Comparison with standards revealed the chemical form was Cr(III) phosphate, which did not vary with manufacturer type (four types analysed) or level of blood metal ions. Cobalt (Co) and molybdenum (Mo) were occasionally present in areas of high Cr. Co was normally found in a metallic state in the tissue, while Mo was found in an oxidized state. The variety of metallic species may have arisen from corrosion, wear or a combination of both. No evidence of Cr(VI) was seen in the tissues examined. PMID:20541630

  11. Excellent results with cementless total hip arthroplasty and alumina-on-alumina pairing: minimum ten-year follow-up

    PubMed Central

    Kress, Alexander M.; Schmidt, Rainer; Holzwarth, Ulrich; Forst, Raimund

    2010-01-01

    Ceramic-on-ceramic coupling is thought to be a durable alternative to metal- or alumina-on-polyethylene pairing. No evidence exists suggesting superior clinical and radiological results for hydroxyapatite-coated stems versus uncoated stems. The aim of this study is to report the performance of an alumina-on-alumina bearing cementless total hip arthroplasty and to compare stems with a tapered design with and without hydroxyapatite coating. We prospectively analysed the results of cementless tapered femoral stems (40 hydroxyapatite-coated versus 22 uncoated stems), a metal-backed fibre mesh hydroxyapatite-coated socket and alumina-on-alumina pairing. Of 75 hips studied, 62 were available for follow-up (mean of 10.5 years after surgery). The average Harris hip score was 90. Only one hydroxyapatite-coated stem was revised for aseptic loosening. One instance of non-progressive osteolysis was detected around a screw of a cup. All other components showed radiographic signs of stable ingrowth. Hydroxyapatite coating of the stem had no significant impact on the clinical or radiological results. Total hip arthroplasty with the presented implant and pairing provides a durable standard for all patients requiring hip joint replacement against which all newer generations of cementless implants should be judged. PMID:21079952

  12. Economic viability of geriatric hip fracture centers.

    PubMed

    Clement, R Carter; Ahn, Jaimo; Mehta, Samir; Bernstein, Joseph

    2013-12-01

    Management of geriatric hip fractures in a protocol-driven center can improve outcomes and reduce costs. Nonetheless, this approach has not spread as broadly as the effectiveness data would imply. One possible explanation is that operating such a center is not perceived as financially worthwhile. To assess the economic viability of dedicated hip fracture centers, the authors built a financial model to estimate profit as a function of costs, reimbursement, and patient volume in 3 settings: an average US hip fracture program, a highly efficient center, and an academic hospital without a specific hip fracture program. Results were tested with sensitivity analysis. A local market analysis was conducted to assess the feasibility of supporting profitable hip fracture centers. The results demonstrate that hip fracture treatment only becomes profitable when the annual caseload exceeds approximately 72, assuming costs characteristic of a typical US hip fracture program. The threshold of profitability is 49 cases per year for high-efficiency hip fracture centers and 151 for the urban academic hospital under review. The largest determinant of profit is reimbursement, followed by costs and volume. In the authors’ home market, 168 hospitals offer hip fracture care, yet 85% fall below the 72-case threshold. Hip fracture centers can be highly profitable through low costs and, especially, high revenues. However, most hospitals likely lose money by offering hip fracture care due to inadequate volume. Thus, both large and small facilities would benefit financially from the consolidation of hip fracture care at dedicated hip fracture centers. Typical US cities have adequate volume to support several such centers. PMID:24579222

  13. Thin hydroxyapatite surface layers on titanium produced by ion implantation

    NASA Astrophysics Data System (ADS)

    Baumann, H.; Bethge, K.; Bilger, G.; Jones, D.; Symietz, I.

    2002-11-01

    In medicine metallic implants are widely used as hip replacement protheses or artificial teeth. The biocompatibility is in all cases the most important requirement. Hydroxyapatite (HAp) is frequently used as coating on metallic implants because of its high acceptance by the human body. In this paper a process is described by which a HAp surface layer is produced by ion implantation with a continuous transition to the bulk material. Calcium and phosphorus ions are successively implanted into titanium under different vacuum conditions by backfilling oxygen into the implantation chamber. Afterwards the implanted samples are thermally treated. The elemental composition inside the implanted region was determined by nuclear analysis methods as (α,α) backscattering and the resonant nuclear reaction 1H( 15N,αγ) 12C. The results of X-ray photoelectron spectroscopy indicate the formation of HAp. In addition a first biocompatibility test was performed to compare the growing of marrow bone cells on the implanted sample surface with that of titanium.

  14. Assessment of modified gold surfaced titanium implants on skeletal fixation

    PubMed Central

    Zainali, Kasra; Danscher, Gorm; Jakobsen, Thomas; Baas, Jorgen; Møller, Per; Bechtold, Joan E.; Soballe, Kjeld

    2013-01-01

    Noncemented implants are the primary choice for younger patients undergoing total hip replacements. However, the major concern in this group of patients regarding revision is the concern from wear particles, periimplant inflammation, and subsequently aseptic implant loosening. Macrophages have been shown to liberate gold ions through the process termed dissolucytosis. Furthermore, gold ions are known to act in an anti-inflammatory manner by inhibiting cellular NF-κB-DNA binding. The present study investigated whether partial coating of titanium implants could augment early osseointegration and increase mechanical fixation. Cylindrical porous coated Ti-6Al-4V implants partially coated with metallic gold were inserted in the proximal region of the humerus in ten canines and control implants without gold were inserted in contralateral humerus. Observation time was 4 weeks. Biomechanical push out tests and stereological histomorphometrical analyses showed no statistically significant differences in the two groups. The unchanged parameters are considered an improvement of the coating properties, as a previous complete gold-coated implant showed inferior mechanical fixation and reduced osseointegration compared to control titanium implants in a similar model. Since sufficient early mechanical fixation is achieved with this new coating, it is reasonable to investigate the implant further in long-term studies. PMID:22847873

  15. Long-term results of cemented total hip arthroplasty in patients younger than 30 years and the outcome of subsequent revisions

    PubMed Central

    2013-01-01

    Background The number of total hip arthroplasties in patients under 30 years is increasing over the years. Almost all of them will face at least one or more future revisions in their life. Therefore, the implant used should have a high survival rate, and needs to be easily revisable resulting in a low re-revision rate. Several studies have evaluated the outcome of total hip arthroplasties in patients under 30 years. However, only a few reported on the follow-up outcome of 10 years or more. In addition, none of these reports published data of the subsequent revisions of these implants within their original report. Methods We studied historically prospective collected data of 48 consecutive patients (69 hips) younger than 30 years, treated with a cemented primary total hip prosthesis between 1988 and 2004. Since the last evaluation of this cohort, two patients were lost to follow-up. For all hip revisions in this cohort, again cemented implants were used, mostly in combination with bone impaction grafting. Kaplan-Meier survival curves at 10- and 15 years for the primary total hip arthroplasties and revisions were determined. Results The mean age at time of primary surgery was 25 years (range, 16 to 29 years). Mean follow-up of the primary hips was 11.5 years (range, 7 to 23 years). During follow-up 13 revisions were performed; in 3 cases a two-stage total revision was performed for septic loosening and 9 cups were revised for aseptic loosening. There were no aseptic stem revisions. The 10 and 15-year survival rates with endpoint revision for aseptic loosening of the primary total hip were 90% (95% CI: 79 to 96) and 82% (95% CI: 65 to 92) respectively. None of our 13 subsequent revisions needed a re-revision within 10 years after re-implantation. Conclusions Cemented total hip implants in patients under 30 years have an encouraging outcome at 10 and 15 years after surgery in these young patients. The 13 revised hips, treated with bone grafting and the third generation cement technique, were performing well with no re-revisions within ten years after surgery. PMID:23339294

  16. Cover Story: The Miseducation of Hip-Hop.

    ERIC Educational Resources Information Center

    Evelyn, Jamilah

    2000-01-01

    Some higher education officials believe that hip-hop music is eating away at the morals, and ultimately the classroom experience, of today's college students. Discusses why the gap exists between student and faculty attitudes toward hip-hop, how hip-hop music represents blackness, how people perceive hip-hop youth, the positive side of hip-hop,…

  17. Effect of n-implantation on the corrosive-wear properties of surgical Ti-6Al-4V alloy

    SciTech Connect

    Williams, J.M.; Beardsley, G.M.; Buchanan, R.A.; Bacon, R.K.

    1984-01-01

    The effects of N-ion implantation on the corrosive-wear properties of Ti-6Al-4V, an alloy used for construction of the femoral component of artificial hip joints in humans, were tested. In corrosive-wear tests designed to simulate pertinent hip-joint parameters, electrochemical corrosion currents were measured for cylindrical samples in saline electrolyte in an arrangement which allowed the samples to be rotated between loaded polyethylene pads simultaneously with the current measurement. To further quantify material removal, Zr markers were ion-implanted into some samples so that, by use of Rutherford backscattering, material removal could be detected by changes in position of the marker relative to the surface. Corrosion currents were greatly reduced by implantation of approximately 20 at. % N, but even implantation of the Zr markers also reduced corrosion currents. The marker experiments confirmed the low rate of material removal for the implanted samples. 10 references, 5 figures, 1 table.

  18. Measurement outcomes from hip simulators.

    PubMed

    de Villiers, Danielle; Shelton, Julia C

    2016-05-01

    Simulation of wear in total hip replacements has been recognised as an important factor in determining the likelihood of clinical success. However, accurate measurement of wear can be problematic with factors such as number and morphology of wear particles produced as well as ion release proving more important in the biological response to hip replacements than wear volume or wear rate alone. In this study, hard-on-hard (CoCr alloy, AgCrN coating) and hard-on-soft (CoCr alloy and CrN coating on vitamin E blended highly cross-linked polyethylene) bearing combinations were tested in an orbital hip simulator under standard and some adverse conditions. Gravimetric wear rates were determined for all bearings, with cobalt and where applicable, silver release determined throughout testing. Isolation of wear particles from the lubricating fluid was used to determine the influence of different bearing combinations and wear conditions on particle morphology. It was found that cobalt and silver could be measured in the lubricating fluid even when volumetric wear was not detectable. In hard-on-hard bearings, Pearson's correlation of 0.98 was established between metal release into the lubricating fluid and wear volume. In hard-on-soft bearings, coating the head did not influence the polyethylene wear rates measured under standard conditions but did influence the cobalt release; the diameter influenced both polyethylene wear and cobalt release, and the introduction of adverse testing generated smaller polyethylene particles. While hip simulators can be useful to assess the wear performance of a new material or design, measurement of other outcomes may yield greater insight into the clinical behaviour of the bearings in vivo. PMID:26888886

  19. Transcriptional regulator-mediated activation of adaptation genes triggers CRISPR de novo spacer acquisition

    PubMed Central

    Liu, Tao; Li, Yingjun; Wang, Xiaodi; Ye, Qing; Li, Huan; Liang, Yunxiang; She, Qunxin; Peng, Nan

    2015-01-01

    Acquisition of de novo spacer sequences confers CRISPR-Cas with a memory to defend against invading genetic elements. However, the mechanism of regulation of CRISPR spacer acquisition remains unknown. Here we examine the transcriptional regulation of the conserved spacer acquisition genes in Type I-A of Sulfolobus islandicus REY15A. Csa3a, a MarR-like transcription factor encoded by the gene located adjacent to csa1, cas1, cas2 and cas4 cluster, but on the reverse strand, was demonstrated to specifically bind to the csa1 and cas1 promoters with the imperfect palindromic sequence. Importantly, it was demonstrated that the transcription level of csa1, cas1, cas2 and cas4 was significantly enhanced in a csa3a-overexpression strain and, moreover, the Csa1 and Cas1 protein levels were increased in this strain. Furthermore, we demonstrated the hyperactive uptake of unique spacers within both CRISPR loci in the presence of the csa3a overexpression vector. The spacer acquisition process is dependent on the CCN PAM sequence and protospacer selection is random and non-directional. These results suggested a regulation mechanism of CRISPR spacer acquisition where a single transcriptional regulator senses the presence of an invading element and then activates spacer acquisition gene expression which leads to de novo spacer uptake from the invading element. PMID:25567986

  20. The Internal Transcribed Spacer Region of Belonolaimus (Nemata: Belonolaimidae)

    PubMed Central

    Cherry, T.; Szalanski, A. L.; Todd, T. C.; Powers, T. O.

    1997-01-01

    Belonolaimus isolates from six U.S. states were compared by restriction endonuclease digestion of amplified first internal transcribed spacer region (ITS1) of the nuclear ribosomal genes. Seven restriction enzymes were selected for evaluation based on restriction sites inferred from the nucleotide sequence of a South Carolina Belonolaimus isolate. Amplified product size from individuals of each isolate was approximately 700 bp. All Midwestern isolates gave distinct restriction digestion patterns. Isolates identified morphologically as Belonolaimus longicaudatus from Florida, South Carolina, and Palm Springs, California, were identical for ITS1 restriction patterns. The correlation between ITS1 restriction patterns and the distribution of B. longicaudatus isolates suggest that the California isolate is a relatively recent introduction into the state. PMID:19274130