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1

Two-stage revision surgery with preformed spacers and cementless implants for septic hip arthritis: a prospective, non-randomized cohort study  

Microsoft Academic Search

Background  Outcome data on two-stage revision surgery for deep infection after septic hip arthritis are limited and inconsistent. This\\u000a study presents the medium-term results of a new, standardized two-stage arthroplasty with preformed hip spacers and cementless\\u000a implants in a consecutive series of adult patients with septic arthritis of the hip treated according to a same protocol.\\u000a \\u000a \\u000a \\u000a \\u000a Methods  Nineteen patients (20 hips) were

Carlo L Romanò; Delia Romanò; Enzo Meani; Nicola Logoluso; Lorenzo Drago

2011-01-01

2

Hip Implant Systems  

MedlinePLUS

... Devices Products and Medical Procedures Implants and Prosthetics Metal-on-Metal Hip Implants Section Contents Menu Products and Medical Procedures Implants and Prosthetics Metal-on-Metal Hip Implants The Hip Joint Hip ...

3

Hip Instability in 2Stage Reimplantation Without an Articulating Spacer  

Microsoft Academic Search

Hip instability is a common postoperative complication after revision surgery. This study sought to define the prevalence of hip instability after 2-stage reimplantation without an articulating spacer. A joint registry review identified 110 patients undergoing 2-stage reimplantation. Fifty-five patients (56 hips) were alive at the time of data collection. Instability was documented and risk factors were analyzed. Of the 56

Thomas K. Fehring; Susan Odum; Stephen Struble; Keith Fehring; William L. Griffin; J. Bohannon Mason

2007-01-01

4

Two-Stage Revision Total Hip Arthroplasty for Periprosthetic Infections Using Antibiotic-Impregnated Cement Spacers of Various Types and Materials  

PubMed Central

Antibiotic-impregnated hip cement spacers of various types and materials have been used in the treatment of periprosthetic hip infections. We developed a handmade spacer by using polymethylmethacrylate (PMMA) and/or ?-tricalcium phosphate (?-TCP). In this study, we retrospectively reviewed the surgical outcomes in 36 consecutive patients treated with 2-stage revision total hip arthroplasty by using our antibiotic-impregnated hip cement spacers. We aimed to analyze the infection control and reinfection rates after revision surgery. Moreover, we analyzed the possible predictors of postoperative reinfection. After exclusion of 1 patient who died immediately after the first-stage surgery, infection was controlled in 33 of the 36 hips (success rate, 91.7%). Two of these 33 hips underwent resection arthroplasty. Of the 36 hips that had been treated with the antibiotic-cement spacer, 31 hips (86.1%) were eligible for the second-stage prosthesis re-implantation. The 31 protocol hip joints of patients followed up for >6 months (mean, 48.6 months). Ten of these 31 hips (32.3%) became reinfected. No possible predictor examined differed significantly between the reinfection-positive and reinfection-negative groups. However, spacers consisting of PMMA cement alone were associated with the highest risk of reinfection. Therefore, ?-TCP-containing antibiotic-impregnated hip cement spacers might decrease the reinfection rate in patients undergoing re-implantation. PMID:24381509

Takahira, Naonobu; Moriya, Mitsutoshi; Yamamoto, Takeaki; Minegishi, Yojiro; Sakai, Rina; Itoman, Moritoshi; Takaso, Masashi

2013-01-01

5

Radiographic evaluation of hip implants.  

PubMed

Serial radiographs are the mainstay in the longitudinal assessment of hip implants. The prosthesis, periprosthetic bone, and juxta-articular soft tissues are inspected for fracture, periosteal reaction, stress shielding, calcar resorption, osteolysis, bony remodeling, metallic debris, and heterotopic ossification. Comparison radiographs best confirm implant migration, subsidence, and aseptic loosening. Infection, particle disease, reaction to metal, and mechanical impingement are important causes of postsurgical pain, but in their earliest stages they may be difficult to diagnose using radiographs. This article addresses the role of radiography following hip arthroplasty. PMID:25633021

Chang, Connie Y; Huang, Ambrose J; Palmer, William E

2015-02-01

6

Burnishing Techniques Strengthen Hip Implants  

NASA Technical Reports Server (NTRS)

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.

2010-01-01

7

A Hip Implant Energy Harvester  

NASA Astrophysics Data System (ADS)

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 ?W was achieved with an optimum resistive load of 250?.

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

2014-11-01

8

(ii) Implant removal in revision hip surgery  

Microsoft Academic Search

Implant removal is a major part of revision hip surgery. A complication, such as fracture or perforation during implant removal, more common in the presence of surrounding osteopenia, can compromise subsequent reconstruction. Similarly, care must be taken to avoid additional bone loss during implant removal. Various techniques are available on both the femoral and acetabular sides that can facilitate the

Andrew R. J. Manktelow

2009-01-01

9

Release of Gentamicin and Vancomycin from Preformed Spacers in Infected Total Hip Arthroplasties: Measurement of Concentrations and Inhibitory Activity in Patients' Drainage Fluids and Serum  

PubMed Central

Gentamicin (G) and vancomycin (V) concentrations in drainage fluids obtained from patients during the first 24 hours after implantation of antibiotic-loaded polymethylmethacrylate (PMMA) spacers in two-stage revision of infected total hip arthroplasty were studied. The inhibitory activity of drainage fluids against different multiresistant clinical isolates was investigated as well. Seven hips were treated by implantation of industrial G-loaded spacers. Vancomycin was added by manually mixing with PMMA bone cement. Serum and drainage fluid samples were collected 1, 4, and 24 hours after spacer implantation. Antibiotics concentrations and drains bactericidal titer of combination were determined against multiresistant staphylococcal strains. The release of G and V from PMMA cement at the site of infection was prompt and effective. Serum levels were below the limit of detection. The local release kinetics of G and V from PMMA cement was similar, exerting a pronounced, combined inhibitory effect in the implant site. The inhibitory activity of drainage fluids showed substantial intersubject variability related to antibiotic concentrations and differed according to the pathogens tested. Gentamicin and vancomycin were released from temporary hip spacers at bactericidal concentrations, and their use in combination exerted strong inhibition against methicillin-resistant S. aureus and Coagulase Negative Staphylococci strains. PMID:24174916

Sandri, Andrea; Samaila, Elena; Magnan, Bruno

2013-01-01

10

Hip Implant Modified To Increase Probability Of Retention  

NASA Technical Reports Server (NTRS)

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.

Canabal, Francisco, III

1995-01-01

11

Revision hip arthroplasty prosthesis: a study implant stability  

Microsoft Academic Search

Revision total hip replacement has high rates of failure, which appear to be due in part to deficient bone stock that does\\u000a not provide an adequate environment for implant fixation. We reviewed the clinical outcomes and implant stability following\\u000a total hip revisions using the S-ROM implant. Between 1996 to 2001, we performed 62 cementless revision hip arthroplasties\\u000a using the S-ROM

M. El-Deen; S. Zahid; D. T. Miller; A. Nargol; R. Logishetty

2006-01-01

12

Hip And Knee Implants: Current Trends And Policy  

Microsoft Academic Search

This paper constitutes an analysis of the issues, relationships, emerging hos- pital strategies, and policy needs surrounding hip and knee implants. Demand for hip and knee replacements is rising annually, and growth is expected to be substantial. Costs are high, reaching $11 billion for hospitals in 2004 and $5 billion for Medicare in 2006. Rela- tionships among stakeholders add complexity.

Natalia A. Wilson; Eugene S. Schneller; Kathleen Montgomery; Kevin J. Bozic

13

Hip Capsulolabral Spacer Placement for the Treatment of Severe Capsulolabral Adhesions After Hip Arthroscopy  

PubMed Central

Recently, there has been a rapid increase in the number of hip arthroscopies performed. The increase in the number of primary surgeries has been associated with a similar increase in the number of revision procedures. The most frequent indications for revision hip arthroscopy are residual bony deformity (impingement), persistent labral pathology, and intra-articular adhesions. Our current understanding of capsulolabral adhesions is limited. Although adhesions between the capsule and labrum are common after hip arthroscopy, generally, they are mild and asymptomatic. However, in severe cases they may cause persistent synovitis and pain, and they may tether the labrum away from the femoral head, causing loss of the suction-seal effect. Such patients present with nonspecific symptoms such as persistent pain, giving way, catching, and pain in hip flexion. Magnetic resonance imaging can aid in the diagnosis by showing the absence of liquid in the capsulolabral recess, although the definitive diagnosis is based on dynamic arthroscopic evaluation. We present our approach to the lysis of capsulolabral adhesions with preservation of labral tissue and describe a technique that uses an iliotibial band allograft to prevent recurrence of such adhesions by maintaining space between the capsule and labrum. PMID:24904779

Philippon, Marc J.; Ferro, Fernando P.; Nepple, Jeffrey J.

2014-01-01

14

Prolonged implantation of an antibiotic cement spacer for management of shoulder sepsis in compromised patients.  

PubMed

The purpose of this report is to present the preliminary results after treatment of shoulder sepsis with prolonged implantation of an antibiotic-loaded cement spacer in a selected group of compromised patients. The current study included 11 patients (9 men and 2 women) with a mean age of 64 years (range, 36-79 years). All patients were treated with radical débridement, implantation of an antibiotic-impregnated polymethylmethacrylate spacer, and 6 weeks of antibiotic therapy. The subjective complaints, range of motion of the shoulder, functional outcome (mini-Quick Disability of the Arm, Shoulder, and Hand score), and radiographic findings were evaluated. At a mean follow-up of 22 months (range, 15-26 months), 9 patients were free of infection, with pain relief and adequate shoulder function for activities of daily living. Radiographic evaluation revealed no loosening or fracture of the spacer and no progressive degenerative changes involving the glenoid. Prolonged implantation of the spacer may be a useful alternative in selected patients with poor general condition. PMID:17931905

Themistocleous, George; Zalavras, Charalampos; Stine, Ian; Zachos, Vasileios; Itamura, John

2007-01-01

15

Revision total hip arthroplasty: the femoral side using cemented implants  

Microsoft Academic Search

Advances in surgical technique and implant technology have improved the ten-year survival after primary total hip arthroplasty\\u000a (THA). Despite this, the number of revision procedures has been increasing in recent years, a trend which is predicted to\\u000a continue into the future. Revision THA is a technically demanding procedure often complicated by a loss of host bone stock\\u000a which may be

Graeme Holt; Samantha Hook; Matthew Hubble

2011-01-01

16

Optimal design of composite hip implants using NASA technology  

NASA Technical Reports Server (NTRS)

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.

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

1993-01-01

17

Saving Implants BMP-2 Application in Revision Total Hip Surgery  

PubMed Central

Objective: Besides others, there are two major problems in total hip replacement surgery which result in implant failure. First there is aseptic loosening due to a lack of implant biocompatibility or micromovements and second periimplant wear debris induced osteolysis which limits the survival rate of an implant. Regarding to recent data there are only limited therapeutic strategies to heal these bony defects without arthroplasty revision surgery. Since the investigation and characterization of adult mesenchymal stem cells (MSCs) from bone marrow, a cell and tissue engineering based therapy might be a promising solution to heal endoprosthesis associated bony defects. Moreover the application of growth factors in bone reconstructive surgery is another treatment concept to promote local bone regeneration. Patient and Methods: We report about a 73-year old patient with a painful weight bearing and a large, wear debris induced pelvic osteolysis after total hip arthroplasty. To prevent from salvage surgical procedures and preserve bone, a healing attempted was performed by filling the critical bony defect zone with a BMP-2/MSC composit. Results: Clinical and radiological follow-ups showed a progressive bony healing of the critical size defect area without any complications. Fifteen months after application the patient is still pain free, has no limitations in daily life or sport activities. Conclusion: The case embarks on a strategy of non-embryonic stem cell and growth factor application to heal bony defects at patients with total hip endoprosthesis. PMID:23674982

Jäger, M.; Emami, R.; Thorey, F.; Krauspe, R.

2006-01-01

18

BMPs in periprosthetic tissues around aseptically loosened total hip implants  

PubMed Central

Background and purpose Primary and dynamically maintained periprosthetic bone formation is essential for osseointegration of hip implants to host bone. Bone morphogenetic proteins (BMPs) play a role in osteoinductive bone formation. We hypothesized that there is an increased local synthesis of BMPs in the synovial membrane-like interface around aseptically loosened total hip replacement (THR) implants, as body attempts to generate or maintain implant fixation. Patients and methods We compared synovial membrane-like interface tissue from revised total hip replacements (rTHR, n = 9) to osteoarthritic control synovial membrane samples (OA, n = 11. Avidin-biotin-peroxidase complex staining and grading of BMP-2, BMP-4, BMP-6, and BMP-7 was done. Immunofluorescence staining was used to study BMP proteins produced by mesenchymal stromal/stem cells (MSCs) and osteoblasts. Results and interpretation All BMPs studied were present in the synovial lining or lining-like layer, fibroblast-like stromal cells, interstitial macrophage-like cells, and endothelial cells. In OA and rTHR samples, BMP-6 positivity in cells, inducible by the proinflammatory cytokines tumor necrosis factor?? and interleukin-1?, predominated over expression of other BMPs. Macrophage-like cells positive for BMP-4, inducible in macrophages by stimulation with particles, were more frequent around loosened implants than in control OA samples, but apparently not enough to prevent loosening. MSCs contained BMP-2, BMP-4, BMP-6, and BMP-7, but this staining diminished during osteogenesis, suggesting that BMPs are produced by progenitor cells in particular, probably for storage in the bone matrix. PMID:20515435

2010-01-01

19

Acute bilateral ECT in a depressed patient with a hip-aztreonam-spacer and subsequent maintenance ECT after prosthesis collocation.  

PubMed

ABSTRACT Electroconvulsive Therapy (ECT) has been demonstrated to be a safe and effective treatment for geriatric depression, although its application might be challenging when medical comorbidities exist. The present case reports a 78-year-old man diagnosed with recurrent unipolar major depressive disorder (MDD), who presented with a severe depressive episode with psychotic features (DSM IV). He successfully received a course of bitemporal (BT) ECT with a hip-aztreonam-spacer due to a hip fracture that occurred during hospitalization. This was followed by maintenance ECT (M-ECT) with a recent prosthesis collocation. This particular case illustrates the importance of a multidisciplinary approach in geriatric patients with somatic complications receiving ECT. PMID:25381759

Gálvez, Verònica; de Arriba Arnau, Aida; Martínez-Amorós, Erika; Ribes, Carmina; Urretavizcaya, Mikel; Cardoner, Narcís

2014-11-10

20

Retrieval Wear Analysis of Metal-on-Metal Hip Resurfacing Implants Revised Due to Pseudotumours  

Microsoft Academic Search

\\u000a Pseudotumours (soft-tissue masses relating to the hip joint) following metal-on-metal hip resurfacing arthroplasty (MoMHRA)\\u000a have been associated with elevated serum and hip aspirate metal ion levels, suggesting that pseudotumours occur when there\\u000a is increased wear. We aimed to quantify in vivo wear of implants revised for pseudotumours (8) and a control group of implants\\u000a (22) revised for other reasons of

Young-Min Kwon; Harinderjit S. Gill; David W. Murray; Amir Kamali

21

Effects of calcium ion implantation on osseointegration of surface-blasted titanium alloy femoral implants in a canine total hip arthroplasty model  

Microsoft Academic Search

Osteoconductivity of titanium-alloy implants may be improved when surface-modified by calcium ion (Ca2+) implantation. We studied the effects of Ca2+ implantation on osseointegration of a grit-blasted titanium-alloy stem using a canine total hip arthroplasty model. Fifteen dogs underwent bilateral hip arthroplasties and were sacrificed at 1, 6, and 12 months postoperatively. The hip components were evaluated by radiographic, qualitative, and

Tetsuya Jinno; Sarah K Kirk; Sadao Morita; Victor M Goldberg

2004-01-01

22

Incidence and Cost of Intraoperative Waste of Hip and Knee Arthroplasty Implants  

Microsoft Academic Search

Many strategies have been reported for decreasing the cost of orthopedic procedures, but prosthetic waste has not been investigated. The purpose of this study was to characterize the cost of intraoperative waste of hip and knee implants. A regional prospective assessment was performed, evaluating the reasons for component waste, the cost of the wasted implants, and where the cost was

Michael G. Zywiel; Slif D. Ulrich; Arnold J. Suda; James L. Duncan; Mike S. McGrath; Michael A. Mont

2010-01-01

23

Static coefficient of friction between stainless steel and PMMA used in cemented hip and knee implants  

Microsoft Academic Search

BackgroundDesign of cemented hip and knee implants, oriented to improve the longevity of artificial joints, is largely based on numerical models. The static coefficient of friction between the implant and the bone cement is necessary to characterize the interface conditions in these models and must be accurately provided. The measurement of this coefficient using a repeatable and reproducible methodology for

N. Nuño; R. Groppetti; N. Senin

2006-01-01

24

Range of Motion after Total Hip Arthoplastry: Simulation of Non-axisymmetric Implants  

Microsoft Academic Search

Dislocation following total hip replacement surgery represents a significant cause of early failure, incurring additional\\u000a medical costs and patient distress. One major cause of dislocation is implant impingement. The most important factor in preventing\\u000a implant impingement is correct implant orientation. This paper describes the newest version of a prosthetic range of motion\\u000a simulator which permits prediction of prosthetic range of

Constantinos Nikou; Branislav Jaramaz; Anthony M. Digioia

1998-01-01

25

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

PubMed

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

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

2012-01-01

26

High-Tech Hip Implant for Wireless Temperature Measurements In Vivo  

PubMed Central

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

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

2012-01-01

27

The influence of the centre of rotation on implant survival using a modular stem hip prosthesis  

Microsoft Academic Search

The restoration of the hip centre of rotation in an anatomical position is considered to be relevant for total hip prosthesis\\u000a survival. When the cup is implanted with a high centre of rotation, the lever arm of the abductor muscles is decreased, causing\\u000a higher joint-reaction forces. Modular stems with varying lengths and geometries can be used to balance soft tissues,

Francesco Traina; Marcello De Fine; Federico Biondi; Enrico Tassinari; Andrea Galvani; Aldo Toni

2009-01-01

28

Mechanical properties of human bone-implant interface tissue in aseptically loose hip implants.  

PubMed

The main cause of failure in total hip replacement is aseptic loosening which is associated with the formation of a periprosthetic fibrous (interface) tissue. Despite important applications for finite element modeling of loose implants, the mechanical properties of the bone-implant interface tissue have never been measured in humans. In this study, we performed unconfined compression tests to characterize the mechanical properties of the interface tissue and to determine the parameters of various hyperelastic material models which were fitted to the measurements. Human interface tissues were retrieved during 21 elective revision surgeries from aseptically loosened cemented (N=10) and uncemented hip implants (N=11). Specimens were tested at a fixed deformation rate of 0.1mm/min up to a maximum force of 10N. Elastic moduli for low and high strain regions of the stress-strain curves were determined. Interface tissue from aseptically loose cemented prostheses shows higher elastic moduli (mean=1.85MPa, 95% C.I.=1.76-1.95MPa) in the high strain region as compared to that of the interface tissue from the cementless group (mean=1.65MPa, 95% C.I.=1.43-1.88MPa). The 5-terms Mooney-Rivlin model ( [Formula: see text] ) described the stress-strain behavior the best. Large variations in the mechanical behavior were observed both between specimens from the same patient as between those of different patients. The material model parameters were therefore estimated for the mean data as well as for the curves with the highest and lowest strain at the maximum load. The model parameters found for the mean data were C1=-0.0074MPa, C2=0.0019MPa, C3=0MPa, C4=-0.0032MPa and C5=0MPa in the cemented group and C1=-0.0137MPa, C2=0.0069MPa, C3=0.0026MPa, C4=-0.0094MPa and C5=0MPa in the cementless group. The results of this study can be used in finite element computer. PMID:25023868

Kraaij, Gert; Zadpoor, Amir A; Tuijthof, Gabrielle J M; Dankelman, Jenny; Nelissen, Rob G H H; Valstar, Edward R

2014-10-01

29

Implant use for primary hip and knee arthroplasty: are we getting it right first time?  

PubMed

Implants used for hip and knee arthroplasties have recently come under increased scrutiny. In England, a large variety of prostheses are currently being used. With the need for savings within the NHS of up to £20 billion over the next five years, we should be 'getting it right first time' by using the most reliable implants with proven survivorship. The 8th Annual Report from the NJR (2011) reporting on prostheses used in 2010 was analysed to determine whether implants had published survivorship data. This study demonstrates that the majority of implants did have long-term results but a small percentage had no published data. The cost of these implants was calculated to see if the implants provided best value for money based on survivorship. Implant choice was also correlated to revision rates published in the NJR report (2011) to help determine whether their continued use was justified. PMID:23507062

Ng Man Sun, Stephen; Gillott, Elizabeth; Bhamra, Jagmeet; Briggs, Tim

2013-06-01

30

Mechanical strength of sliding crew-plate hip implants. A biomechanical study of unstable trochanteric fractures. VI.  

PubMed

Static load testing of sliding screw-plate hip implants manufactured from Cobalt-Chromium-Molybdenum alloy or 316 LVM stainless steel was performed. Implant angles of 135 degrees and 150 degrees were applied and the telescoping ability eliminated by gluing the screw to the barrel of the implant. In comparison with the results obtained in tests of McLaughlin and Jewett hip implants superior yield loads were determined for both implant angles. Calculations were made of the improvement of implant strength due to telescoping. Implants with a 135 degree angle are recommended for the fixation of unstable trochanteric fractures, as the hip joint load during normal level walking does not exceed the yield load of these implants. PMID:7446052

Jensen, J S

1980-08-01

31

Effect of price capitation on implant selection for primary total hip and knee arthroplasty.  

PubMed

While price capitation strategies may help to control total hip (THA) and knee arthroplasty (TKA) implant costs, its effect on premium implant selection is unclear. Primary THA and TKA cases 6 months before and after capitated pricing implementation were retrospectively identified. After exclusions, 716 THA and 981 TKA from a large academic hospital and 2 midsize private practice community hospitals were reviewed. Academic hospital surgeons increased premium THA implant usage (66.5% to 70.6%; P = 0.28), while community surgeons selected fewer premium implants (36.4%) compared to academic surgeons, with no practice change (P = 0.95). Conversely, premium TKA implant usage significantly increased (73.4% to 89.4%; P < 0.001) for academic surgeons. Community surgeons used premium TKA implants at greater rates in both periods, with all cases having ?1 premium criterion. PMID:24679475

Farías-Kovac, Mario; Szubski, Caleb R; Hebeish, Mark; Klika, Alison K; Mishra, Kirtishri; Barsoum, Wael K

2014-07-01

32

Fluoroscopy-guided implantation of subacromial "biodegradable spacer" using local anesthesia in patients with irreparable rotator cuff tear.  

PubMed

Treatment of massive rotator cuff tears can be challenging, especially when tears are considered irreparable or, when repaired, at significant risk of retear. A surgical technique is described using a biodegradable subacromial balloon-shaped spacer (InSpace; Ortho-Space, Caesarea, Israel) that, when implanted between the humeral head and acromion, permits smooth, frictionless gliding, supporting shoulder biomechanics. The specific insertion technique described herein is a simple procedure that can be performed in a day-care or outpatient setting with patients under local anesthesia, thus providing a treatment option for patients with multiple comorbidities complicating or contraindicating surgery, such as reverse arthroplasty under general anesthesia. PMID:25264508

Gervasi, Enrico; Cautero, Enrico; Dekel, Assaf

2014-08-01

33

Fluoroscopy-Guided Implantation of Subacromial “Biodegradable Spacer” Using Local Anesthesia in Patients With Irreparable Rotator Cuff Tear  

PubMed Central

Treatment of massive rotator cuff tears can be challenging, especially when tears are considered irreparable or, when repaired, at significant risk of retear. A surgical technique is described using a biodegradable subacromial balloon-shaped spacer (InSpace; Ortho-Space, Caesarea, Israel) that, when implanted between the humeral head and acromion, permits smooth, frictionless gliding, supporting shoulder biomechanics. The specific insertion technique described herein is a simple procedure that can be performed in a day-care or outpatient setting with patients under local anesthesia, thus providing a treatment option for patients with multiple comorbidities complicating or contraindicating surgery, such as reverse arthroplasty under general anesthesia. PMID:25264508

Gervasi, Enrico; Cautero, Enrico; Dekel, Assaf

2014-01-01

34

A biomechanical assessment of modular and monoblock revision hip implants using FE analysis and strain gage measurements  

PubMed Central

Background The bone loss associated with revision surgery or pathology has been the impetus for developing modular revision total hip prostheses. Few studies have assessed these modular implants quantitatively from a mechanical standpoint. Methods Three-dimensional finite element (FE) models were developed to mimic a hip implant alone (Construct A) and a hip implant-femur configuration (Construct B). Bonded contact was assumed for all interfaces to simulate long-term bony ongrowth and stability. The hip implants modeled were a Modular stem having two interlocking parts (Zimmer Modular Revision Hip System, Zimmer, Warsaw, IN, USA) and a Monoblock stem made from a single piece of material (Stryker Restoration HA Hip System, Stryker, Mahwah, NJ, USA). Axial loads of 700 and 2000 N were applied to Construct A and 2000 N to Construct B models. Stiffness, strain, and stress were computed. Mechanical tests using axial loads were used for Construct A to validate the FE model. Strain gages were placed along the medial and lateral side of the hip implants at 8 locations to measure axial strain distribution. Results There was approximately a 3% average difference between FE and experimental strains for Construct A at all locations for the Modular implant and in the proximal region for the Monoblock implant. FE results for Construct B showed that both implants carried the majority (Modular, 76%; Monoblock, 66%) of the 2000 N load relative to the femur. FE analysis and experiments demonstrated that the Modular implant was 3 to 4.5 times mechanically stiffer than the Monoblock due primarily to geometric differences. Conclusions This study provides mechanical characteristics of revision hip implants at sub-clinical axial loads as an initial predictor of potential failure. PMID:20462448

2010-01-01

35

Long-term results of 58 hip cup revision arthroplasties using a threaded ring implant  

Microsoft Academic Search

Introduction  There is still a discussion whether cementless hip cup revisions should be performed with a press fit cup or a threaded ring\\u000a implant.\\u000a \\u000a \\u000a \\u000a Materials and methods  The results of 58 hip cup changes using the spherical, threaded ring “Munich” are presented. In 16 cases, the ring “Munich\\u000a I” with a smooth surface and in 42 cases the ring “Munich II” with

Christoph von Schulze Pellengahr; Tobias Düll; Peter E. Müller; Hans Roland Dürr; Andrea Baur-Melnyk; Markus Maier; Christof Birkenmaier; Volkmar Jansson

2007-01-01

36

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

NASA Astrophysics Data System (ADS)

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.

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

2014-02-01

37

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

PubMed Central

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

2012-01-01

38

In vivo implant fixation of carbon fiber-reinforced PEEK hip prostheses in an ovine model.  

PubMed

Carbon fiber-reinforced polyetheretherketone (CFR/PEEK) is theoretically suitable as a material for use in hip prostheses, offering excellent biocompatibility, mechanical properties, and the absence of metal ions. To evaluate in vivo fixation methods of CFR/PEEK hip prostheses in bone, we examined radiographic and histological results for cementless or cemented CFR/PEEK hip prostheses in an ovine model with implantation up to 52 weeks. CFR/PEEK cups and stems with rough-textured surfaces plus hydroxyapatite (HA) coatings for cementless fixation and CFR/PEEK cups and stems without HA coating for cement fixation were manufactured based on ovine computed tomography (CT) data. Unilateral total hip arthroplasty was performed using cementless or cemented CFR/PEEK hip prostheses. Five cementless cups and stems and six cemented cups and stems were evaluated. On the femoral side, all cementless stems demonstrated bony ongrowth fixation and all cemented stems demonstrated stable fixation without any gaps at both the bone-cement and cement-stem interfaces. All cementless cases and four of the six cemented cases showed minimal stress shielding. On the acetabular side, two of the five cementless cups demonstrated bony ongrowth fixation. Our results suggest that both cementless and cemented CFR/PEEK stems work well for fixation. Cup fixation may be difficult for both cementless and cemented types in this ovine model, but bone ongrowth fixation on the cup was first seen in two cementless cases. Cementless fixation can be achieved using HA-coated CFR/PEEK implants, even under load-bearing conditions. PMID:23097319

Nakahara, Ichiro; Takao, Masaki; Bandoh, Shunichi; Bertollo, Nicky; Walsh, William R; Sugano, Nobuhiko

2013-03-01

39

Influence of ingrowth regions on bone remodelling around a cementless hip resurfacing femoral implant.  

PubMed

Hip resurfacing arthroplasty is an alternative to traditional hip replacement that can conserve proximal bone stock and has gained popularity but bone resorption may limit implant survival and remains a clinical concern. The goal of this study was to analyze bone remodelling patterns around an uncemented resurfacing implant and the influence of ingrowth regions on resorption. A computed tomography-derived finite element model of a proximal femur with a virtually implanted resurfacing component was simulated under peak walking loads. Bone ingrowth was simulated by six interface conditions: fully bonded; fully friction; bonded cap with friction stem; a small bonded region at the stem-cup intersection with the remaining surface friction; fully frictional, except for a bonded band along the distal end of the cap and superior half of the cap bonded with the rest frictional. Interface condition had a large influence on remodelling patterns. Bone resorption was minimized when no ingrowth occurred at the bone-implant interface. Bonding only the superior half of the cap increased bone resorption slightly but allowed for a large ingrowth region to improve secondary stability. PMID:24697332

Haider, Ifaz T; Speirs, Andrew D; Beaulé, Paul E; Frei, Hanspeter

2015-09-01

40

Two-stage revision of implant-associated infections after total hip and knee arthroplasty  

PubMed Central

Septic loosening of total hip and knee endoprostheses gains an increasing proportion of revision arthroplasties. Operative revisions of infected endoprostheses are mentally and physically wearing for the patient, challenging for the surgeon and a significant economic burden for healthcare systems. In cases of early infection within the first three weeks after implantation a one-stage revision with leaving the implant in place is widely accepted. The recommendations for the management of late infections vary by far. One-stage revisions as well as two-stage or multiple revision schedules have been reported to be successful in over 90% of all cases for certain patient collectives. But implant associated infection still remains a severe complication. Moreover, the management of late endoprosthetic infection requires specific logistics, sufficient and standardized treatment protocol, qualified manpower as well as an efficient quality management. With regard to the literature and experience of specialized orthopaedic surgeons from several university and regional hospitals we modified a commonly used treatment protocol for two-stage revision of infected total hip and knee endoprostheses. In addition to the achievement of maximum survival rate of the revision implants an optimisation of the functional outcome of the affected artificial joint is aimed for. PMID:22242098

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

2011-01-01

41

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

PubMed

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

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

2014-02-01

42

Antimicrobial activity of gentamicin and vancomycin combination in joint fluids after antibiotic-loaded cement spacer implantation in two-stage revision surgery.  

PubMed

Gentamicin (G) and vancomycin (V) concentrations in joints fluids obtained from patients during the first 24 hours after implantation of antibiotic-loaded polymethylmethacrylate (PMMA) spacers in two-stage revision for infected arthroplasty, and the inhibitory activity of joint fluids against different multiresistant clinical isolates were studied. A total of 12 patients undergoing two-stage revision surgery with implantation of industrial G spacers added with different amounts of V was studied. Serum and joint fluid samples were collected 1, 4, and 24 hours after spacer implantation. Antibiotics concentrations and joint bactericidal titer (JBT) of combination were determined against multiresistant staphylococcal strains. The local release of G and V from PMMA cement seemed prompt and effective. Serum levels were below the limit of detection. The same joint fluid showed different activity according to the susceptibility of the pathogens tested. Gentamicin and V were released from spacers at bactericidal concentrations exerting a strong inhibition against methicillin-resistant Staphylococcus aureus (MRSA) and coagulase-negative staphylococci (CoNS) strains. PMID:24621165

Bertazzoni Minelli, Elisa; Benini, Anna; Samaila, Elena; Bondi, Manuel; Magnan, Bruno

2015-02-01

43

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

PubMed Central

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

2014-01-01

44

Supplemental Information spacer spacer  

E-print Network

assembly RNA-DNA duplex formation Double-stranded DNA break PAM Figure S1. Mechanism of the Type II CRISPR System from S. pyogenes, Related to Figure 1 The system consists of a set of CRISPR-associated (Cas) proteins and a CRISPR locus that contains an array of repeat-spacer sequences. All repeats are the same

Lim, Wendell

45

Failure of a modular hip implant at the stem-sleeve interface.  

PubMed

In the current era of total hip arthroplasty (THA), orthopedic surgeons have several fixation options at their disposal. The modern monoblock prosthesis, introduced by Dr. Sir John Charnley, has seen many modifications since its inception in the 1970s and continues to be the most commonly used prosthesis style for primary and revision THA. Proximal modular sleeve technology was introduced in 1967 by Konstantin Sivash, modifying his original 1956 Sivash Stem design. The design is now known as the S-ROM, and although design modifications continue to date, the fundamental structure of the S-ROM remains essentially unchanged. Several other proximal modular prostheses are now currently available for use in THA. Although this similarity in design enables considerable surgical flexibility, it also links their potential for catastrophic failure. This aim of this article was to present a brief history of proximal modularity in THA and to add to the small body of literature regarding catastrophic failure in modular hip implants, including its proposed etiologies including micromotion, fretting and corrosion. PMID:23823060

Mehran, Nima; North, Trevor; Laker, Michael

2013-07-01

46

Implants et prothèses du poignet et du carpe  

Microsoft Academic Search

Total or partial replacement of the wrist is not yet a current surgery. Total wrist arthroplasty has less satisfactory clinical outcomes compared to hip and knee arthroplasty. With the silicone spacers developed by Swanson, the revision rate is important because of implant fracture, carpal collapse and synovitis but preservation of wrist function through the years seems enhanced by titanium grommet.

P. Ledoux

2004-01-01

47

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

PubMed Central

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?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

2014-01-01

48

Measurement of transient and residual stresses during polymerization of bone cement for cemented hip implants.  

PubMed

The initial fixation of a cemented hip implant relies on the strength of the interface between the stem, bone cement and adjacent bone. Bone cement is used as grouting material to fix the prosthesis to the bone. The curing process of bone cement is an exothermic reaction where bone cement undergoes volumetric changes that will generate transient stresses resulting in residual stresses once polymerization is completed. However, the precise magnitude of these stresses is still not well documented in the literature. The objective of this study is to develop an experiment for the direct measurement of the transient and residual radial stresses at the stem-cement interface generated during cement polymerization. The idealized femoral-cemented implant consists of a stem placed inside a hollow cylindrical bone filled with bone cement. A sub-miniature load cell is inserted inside the stem to make a direct measurement of the radial compressive forces at the stem-cement interface, which are then converted to radial stresses. A thermocouple measures the temperature evolution during the polymerization process. The results show the evolution of stress generation corresponding to volumetric changes in the cement. The effect of initial temperature of the stem and bone as well as the cement-bone interface condition (adhesion or no adhesion) on residual radial stresses is investigated. A maximum peak temperature of 70 degrees C corresponds to a peak in transient stress during cement curing. Maximum radial residual stresses of 0.6 MPa in compression are measured for the preheated stem. PMID:18692188

Nuño, N; Madrala, A; Plamondon, D

2008-08-28

49

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

PubMed Central

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

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

2009-01-01

50

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

PubMed

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

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

2009-01-01

51

Superelastic Orthopedic Implant Coatings  

NASA Astrophysics Data System (ADS)

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.

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

2014-07-01

52

Evaluation of the effects of implant materials and designs on thermal necrosis of bone in cemented hip arthroplasty.  

PubMed

The exothermic polymerization of bone cement may induce thermal necrosis of bone in cemented hip arthroplasty. A finite element formulation was developed to predict the evolution of the temperature with time in the cemented hip replacement system. The developed method is capable of taking into account both the chemical reaction that generates heat during bone cement polymerization (through a kinetic model) and the physical process of heat conduction (with an energy balance equation). The possibility of thermal necrosis of bone was then evaluated based on the temperature history in the bone and an appropriate damage criterion. Specifically, we evaluate the role of implant materials and designs on the thermal response of the system. Results indicated that the peak temperature at the bone/cement interface with a metal prosthesis was lower than that with a polymer or a composite prosthesis in hip replacement systems. Necrosis of bone was predicted to occur with a polymer or a composite prosthesis while no necrosis was predicted with a metal prosthesis in the simulated conditions. When reinforcing osteoporotic hips with injected bone cement in the cancellous core of the femur, the volume of bone cement implanted is increased which may increase the risk of thermal necrosis of bone. We evaluate whether this risk can be decreased through the use of an insulator to contain the bone cement. No thermal necrosis of bone was predicted with a 3 mm thick polyurethane insulator while more damage is predicted for the use of bone cement without the insulator. This method provides a numerical tool for the quantitative simulation of the thermal behavior of bone-cement-prosthesis designs and for examining and refining new designs computationally. PMID:14646056

Li, Chaodi; Kotha, Shiva; Mason, James

2003-01-01

53

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

NASA Astrophysics Data System (ADS)

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.

Varano, Rocco

54

Cost-effectiveness of cemented versus cementless total hip arthroplasty. A Markov decision analysis based on implant cost  

Microsoft Academic Search

Background  Probabilistic decision analysis is a means of reflecting the uncertainty parameter in models and of presenting it in a comprehensible\\u000a manner to decision-makers.\\u000a \\u000a \\u000a \\u000a Materials and methods  A cost-effectiveness model was constructed to compare the cementless and cemented total hip prostheses implanted at our department\\u000a in terms of lifetime costs and quality-adjusted life-years (QALY). Revision rates were obtained from the Orthopaedic Prosthesis

M. Marinelli; A. Soccetti; N. Panfoli; L. de Palma

2008-01-01

55

Spacer fluids  

SciTech Connect

This patent describes a method for cementing a wellbore penetrating an earth formation into which a conduit extends, the wellbore having a space occupied by a drilling fluid. It comprises displacing the drilling fluid from the space with a spacer fluid comprising: sulfonated styrene-maleic anhydride copolymer, bentonite, welan gum, surfactant and a weighting agent; and displacing the spacer composition and filling the wellbore space with a settable cement composition.

Wilson, W.N.; Bradshaw, R.D.; Wilton, B.S.; Carpenter, R.B.

1992-05-19

56

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

MedlinePLUS

... Surgeons Information about Soft Tissue Imaging and Metal Ion Testing Information for All Health Care Professionals who ... the implant and failure of the device. Metal ions from a metal-on-metal implant will enter ...

57

Computer Integrated Revision Total Hip Replacement Surgery: Preliminary Report  

E-print Network

Computer Integrated Revision Total Hip Replacement Surgery: Preliminary Report Leo Joskowicz1, and cement machining. Keywords: computer-assisted surgery, orthopaedics, revision total hip replacement in revision total hip replacement surgery (RTHR). In RTHR surgery, a failing orthopaedic hip implant

Taubin, Gabriel

58

Association between bisphosphonate use and implant survival after primary total arthroplasty of the knee or hip: population based retrospective cohort study  

PubMed Central

Objectives To test whether bisphosphonate use is related to improved implant survival after total arthroplasty of the knee or hip. Design Population based retrospective cohort study. Setting Primary care data from the United Kingdom. Participants All patients undergoing primary total arthroplasty of the knee (n=18?726) or hip (n=23?269) in 1986-2006 within the United Kingdom’s General Practice Research Database. We excluded patients with a history of hip fracture before surgery or rheumatoid arthritis, and individuals younger than 40 years at surgery. Intervention Bisphosphonate users were classified as patients with at least six prescriptions of bisphosphonates or at least six months of prescribed bisphosphonate treatment with more than 80% adherence before revision surgery. Outcome measures Revision arthroplasties occurring after surgery, identified by READ and OXMIS codes. Parametric survival models were used to determine effects on implant survival with propensity score adjustment to account for confounding by indication. Results Of 41?995 patients undergoing primary hip or knee arthroplasty, we identified 1912 bisphosphonate users, who had a lower rate of revision at five years than non-users (0.93% (95% confidence interval 0.52% to 1.68%) v 1.96% (1.80% to 2.14%)). Implant survival was significantly longer in bisphosphonate users than in non-users in propensity adjusted models (hazard ratio 0.54 (0.29 to 0.99); P=0.047) and had an almost twofold increase in time to revision after hip or knee arthroplasty (time ratio 1.96 (1.01 to 3.82)). Assuming 2% failure over five years, we estimated that the number to treat to avoid one revision was 107 for oral bisphosphonates. Conclusions In patients undergoing lower limb arthroplasty, bisphosphonate use was associated with an almost twofold increase in implant survival time. These findings require replication and testing in experimental studies for confirmation. PMID:22147909

2011-01-01

59

Rationale for one stage exchange of infected hip replacement using uncemented implants and antibiotic impregnated bone graft.  

PubMed

Infection of a total hip replacement (THR) is considered a devastating complication, necessitating its complete removal and thorough debridement of the site. It is undoubted that one stage exchange, if successful, would provide the best benefit both for the patient and the society. Still the fear of re-infection dominates the surgeons decisions and in the majority of cases directs them to multiple stage protocols. However, there is no scientifically based argument for that practice. Successful eradication of infection with two stage procedures is reported to average 80% to 98%. On the other hand a literature review of Jackson and Schmalzried (CORR 2000) summarizing the results of 1,299 infected hip replacements treated with direct exchange (almost exclusively using antibiotic loaded cement), reports of 1,077 (83%) having been successful. The comparable results suggest, that the major factor for a successful outcome with traditional approaches may be found in the quality of surgical debridement and dead space management. Failures in all protocols seem to be caused by small fragments of bacterial colonies remaining after debridement, whereas neither systemic antibiotics nor antibiotic loaded bone cement (PMMA) have been able to improve the situation significantly. Reasons for failure may be found in the limited sensitivity of traditional bacterial culturing and reduced antibiotic susceptibility of involved pathogens, especially considering biofilm formation. Whenever a new prosthesis is implanted into a previously infected site the surgeon must be aware of increased risk of failure, both in single or two stage revisions. Eventual removal therefore should be easy with low risk of additional damage to the bony substance. On the other hand it should also have potential of a good long term result in case of success. Cemented revisions generally show inferior long term results compared to uncemented techniques; the addition of antibiotics to cement reduces its biomechanical properties. Efficient cementing techniques will result in tight bonding with the underlying bone, making eventual removal time consuming and possibly associated with further damage to the osseous structures. All these issues are likely to make uncemented revisions more desirable. Allograft bone may be impregnated with high loads of antibiotics using special incubation techniques. The storage capacities and pharmacological kinetics of the resulting antibiotic bone compound (ABC) are more advantageous than the ones of antibiotic loaded cement. ABC provides local concentrations exceeding those of cement by more than a 100fold and efficient release is prolonged for several weeks. The same time they are likely to restore bone stock, which usually is compromised after removal of an infected endoprosthesis. ABC may be combined with uncemented implants for improved long term results and easy removal in case of a failure. Specifications of appropriate designs are outlined. Based on these considerations new protocols for one stage exchange of infected TJR have been established. Bone voids surrounding the implants may be filled with antibiotic impregnated bone graft; uncemented implants may be fixed in original bone. Recent studies indicate an overall success rate of more than 90% without any adverse side effects. Incorporation of allografts appears as after grafting with unimpregnated bone grafts. Antibiotic loaded bone graft seems to provide sufficient local antibiosis for protection against colonisation of uncemented implants, the eluted amounts of antibiotics are likely to eliminate biofilm remnants, dead space management is more complete and defects may be reconstructed efficiently. Uncemented implants provide improved long term results in case of success and facilitated re-revision in case of failure. One stage revision using ABC together with uncemented implants such should be at least comparably save as multiple stage procedures, taking advantage of the obvious benefits for patients and economy. PMID:19834590

Winkler, Heinz

2009-01-01

60

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

PubMed Central

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 ?m 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

2010-01-01

61

ECE 331 -Biomedical Instrumentation Department of Electrical & Computer Engineering, UBC Implant Design & Total Hip Arthroplasty  

E-print Network

. 5. Measure the dimensions of your femur. C) Design implant 1. Download the SolidWorks femur model as an STL file. Set "Deviation" to the smallest possible value and "Angle" to 5 degrees. 7. Email your STL

Pulfrey, David L.

62

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

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

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

2014-01-01

63

Effects of CoCr metal wear debris generated from metal-on-metal hip implants and Co ions on human monocyte-like U937 cells.  

PubMed

Hip resurfacing with cobalt-chromium (CoCr) alloy was developed as a surgical alternative to total hip replacement. However, the biological effects of nanoparticles generated by wear at the metal-on-metal articulating surfaces has limited the success of such implants. The aim of this study was to investigate the effects of the combined exposure to CoCr nanoparticles and cobalt ions released from a resurfacing implant on monocytes (U937 cells) and whether these resulted in morphology changes, proliferation alterations, toxicity and cytokine release. The interaction between prior exposure to Co ions and the cellular response to nanoparticulate debris was determined to simulate the situation in patients with metal-on-metal implants receiving a second implant. Effects on U937 cells were mainly seen after 120h of treatment. Prior exposure to Co ions increased the toxic effects induced by the debris, and by Co ions themselves, suggesting the potential for interaction in vivo. Increased TNF-? secretion by resting cells exposed to nanoparticles could contribute to osteolysis processes in vivo, while increased IFN-? production by activated cells could represent cellular protection against tissue damage. Data suggest that interactions between Co ions and CoCr nanoparticles would occur in vivo, and could threaten the survival of a CoCr metal implant. PMID:25433333

Posada, Olga M; Tate, Rothwelle J; Grant, M Helen

2015-03-01

64

IRAK-M in macrophages around septically and aseptically loosened hip implants.  

PubMed

The most common long-term complication of joint arthroplasty is loosening, which is mediated by chronic inflammatory cytokines produced by macrophages stimulated by implant-derived debris and eventually bacterial components adherent to such debris. In this study, antiinflammatory interleukin-1 receptor-associated kinase-M (IRAK-M) was studied in macrophages in interface membranes in vivo using immunohistochemical staining and in titanium particle-stimulated macrophages in vitro using reverse transcriptase-polymerase chain reaction. Results show that the interface membranes of septically and aseptically loosened prosthesis express more IRAK-M protein than control membranes from osteoarthritic patient and that IRAK-M mRNA-levels increase upon particle stimulation. These findings suggest that, the upregulation of IRAK-M in macrophages is involved in the local immunosuppression around implants, and may contribute to septic and aseptic implant loosening. PMID:21987497

Zhang, Yangchun; Hou, Changhe; Yu, Shiming; Xiao, Jianhong; Zhang, Ziji; Zhai, Qiyi; Chen, Jianwei; Li, Ziqing; Zhang, Xibao; Lehto, Matti; Konttinen, Yrjö T; Sheng, Puyi

2012-01-01

65

High Revision Rate at 5 Years after Hip Resurfacing with the Durom Implant  

Microsoft Academic Search

Background\\/rationale  There is growing evidence that different resurfacing implants are associated with variable survival and revision rates. A\\u000a registry analysis indicated the Durom resurfacing implant had high revision rates at 5 years, whereas three original studies\\u000a reported low revision rates at short-term followups. Thus, the revision rates appear controversial.\\u000a \\u000a \\u000a \\u000a \\u000a Questions\\/purposes  We therefore assessed (1) the survivorship including differences between women and men at

Florian D. Naal; Ronny Pilz; Urs Munzinger; Otmar Hersche; Michael Leunig

66

Alumina-on-alumina hip implants: A wear study of retrieved components.  

PubMed

Alumina-alumina bearings are among the most resistant to wear in total hip replacement. Examination of their surfaces is one way of comparing damage caused by wear of hip joints simulated in vitro to that seen in explanted bearings. The aim of this study was to determine whether second-generation ceramic bearings exhibited a better pattern of wear than those reported in the literature for first-generation bearings. We considered both macro- and microscopic findings. We found that long-term alumina wear in association with a loose acetabular component could be categorised into three groups. Of 20 specimens, four had 'low wear', eight 'crescent wear' and eight 'severe wear', which was characterised by a change in the physical shape of the bearing and a loss of volume. This suggests that the wear in alumina-alumina bearings in association with a loose acetabular component may be variable in pattern, and may explain, in part, why the wear of a ceramic head in vivo may be greater than that seen after in vitro testing. PMID:22219245

Affatato, S; Traina, F; De Fine, M; Carmignato, S; Toni, A

2012-01-01

67

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

PubMed

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

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

2006-02-01

68

Pore Geometry Optimization of Titanium (Ti6Al4V) Alloy, for Its Application in the Fabrication of Customized Hip Implants.  

PubMed

The present study investigates the mechanical response of representative volume elements of porous Ti-6Al-4V alloy, to arrive at a desired range of pore geometries that would optimize the reduction in stiffness necessary for biocompatibility with the stress concentration arising around the pore periphery, under physiological loading conditions with respect to orthopedic hip implants. A comparative study of the two is performed with the aid of a newly defined optimizing parameter called pore efficiency that takes into consideration both the stiffness quantity and the stress localization around pores. To perform a detailed analysis of the response of the porous structure over the entire spectrum of loading conditions that a hip implant is subjected to in vivo, the mechanical responses of 3D finite element models of cubic and rectangular parallelepiped geometries, with porosities varying over a range of 10% to 60%, are simulated under representative compressive, flexural as well as combined loading conditions. The results that are obtained are used to suggest a range of pore diameters that lower the effective stiffness and modulus of the implant to around 60% of the stiffness and modulus of dense solid implants while keeping the stress levels within permissible limits. PMID:25400663

Roy, Sandipan; Panda, Debojyoti; Khutia, Niloy; Chowdhury, Amit Roy

2014-01-01

69

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

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

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

2013-01-01

70

The accuracy of Acuros XB algorithm for radiation beams traversing a metallic hip implant - comparison with measurements and Monte Carlo calculations.  

PubMed

In this study, the clinical benefit of the improved accuracy of the Acuros XB (AXB) algorithm, implemented in a commercial radiotherapy treatment planning system (TPS), Varian Eclipse, was demonstrated with beams traversing a high-Z material. This is also the first study assessing the accuracy of the AXB algorithm applying volumetric modulated arc therapy (VMAT) technique compared to full Monte Carlo (MC) simulations. In the first phase the AXB algorithm was benchmarked against point dosimetry, film dosimetry, and full MC calculation in a water-filled anthropometric phantom with a unilateral hip implant. Also the validity of the full MC calculation used as reference method was demonstrated. The dose calculations were performed both in original computed tomography (CT) dataset, which included artifacts, and in corrected CT dataset, where constant Hounsfield unit (HU) value assignment for all the materials was made. In the second phase, a clinical treatment plan was prepared for a prostate cancer patient with a unilateral hip implant. The plan applied a hybrid VMAT technique that included partial arcs that avoided passing through the implant and static beams traversing the implant. Ultimately, the AXB-calculated dose distribution was compared to the recalculation by the full MC simulation to assess the accuracy of the AXB algorithm in clinical setting. A recalculation with the anisotropic analytical algorithm (AAA) was also performed to quantify the benefit of the improved dose calculation accuracy of type 'c' algorithm (AXB) over type 'b' algorithm (AAA). The agreement between the AXB algorithm and the full MC model was very good inside and in the vicinity of the implant and elsewhere, which verifies the accuracy of the AXB algorithm for patient plans with beams traversing through high-Z material, whereas the AAA produced larger discrepancies. PMID:25207577

Ojala, Jarkko; Kapanen, Mika; Sipilä, Petri; Hyödynmaa, Simo; Pitkänen, Maunu

2014-01-01

71

Implants  

MedlinePLUS

... vs. Alternatives Implants are devices that replace the roots of missing teeth. They are used to support ... confidence. There are several types of implants, including: Root form Subperiosteal Mini Root-form implants are the ...

72

Retaining well-fixed cementless stem in the treatment of infected hip arthroplasty  

PubMed Central

Background and purpose Two-stage reconstruction, reimplantation after removal of an infected prosthesis, has been considered to be the gold standard for treatment of infected hip arthroplasty. However, during the removal of a well-fixed femoral stem, the proximal femur can be damaged and a sequestrum can be formed, which might lead to chronic osteomyelitis and difficulty in reimplantation. We wanted to determine whether infection after hip arthroplasty can be treated without removal of a well-fixed stem. Methods We treated 19 patients who had an infection after hip replacement, but a well-fixed cementless stem, with 2-stage reconstruction. At the first stage, we removed the acetabular cup, the liner and the head, but not the stem. We then implanted a cup of cement spacer. After control of infection, we reimplanted the acetabular component and head. Results 2 patients did not undergo second-stage reconstruction because they were satisfied with the pain relief and the activity that they had with the cement-spacer implantation. The remaining 17 patients underwent the second-stage of the reconstruction using cementless arthroplasty. At a mean follow-up time of 4 (2–8) years, 15 of the patients had no recurrence of infection, with satisfactory clinical and radiographic outcome. Interpretation This second-stage reconstruction after retention of the stem could be an alternative treatment option for periprosthetic infection with a well-fixed stem. PMID:23621807

2013-01-01

73

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

PubMed

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

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

2015-01-15

74

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

PubMed Central

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

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

75

Use of 18 F-FDG-PET in the diagnosis of endoprosthetic loosening of knee and hip implants  

Microsoft Academic Search

Introduction  To diagnose septic and aseptic loosening 18-fluorodeoxyglucose positron emission tomography (18F-FDG-PET) has been described with good results for hip arthroplasties. The purpose of the present study was to examine whether\\u000a there is a difference of feasibility in detecting loosening of hip versus knee prostheses by use of 18F-FDG-PET.\\u000a \\u000a \\u000a \\u000a \\u000a Patients  Thirty-two patients with lower limb arthroplasty complaints (74 components) were studied preoperatively

Susanne Mayer-Wagner; Wolfgang Mayer; Sonja Maegerlein; Rainer Linke; Volkmar Jansson; Peter E. Müller

2010-01-01

76

The reliability of a scoring system for corrosion and fretting, and its relationship to material loss of tapered, modular junctions of retrieved hip implants.  

PubMed

It has been suggested that corrosion and fretting at the tapered, modular junctions of hip arthroplasties may contribute to implant failure. In this study the reliability of a commonly used peer-reviewed scoring system for visual assessment of corrosion and fretting at these junctions was evaluated. Volumetric material loss at the tapered head surface was measured and associations with the visual scores were investigated. We found that the inter-observer reproducibility and single-observer repeatability of the corrosion scores were substantial using Cohen's weighted Kappa statistic (k = 0.64-0.71). The reproducibility and repeatability of the fretting scores however were slight to fair (k = 0.18-0.31). Taper corrosion scores were significantly and moderately correlated with the volume of material loss measured (Spearman's r = 0.59; P < 0.001). We recommend the continued use of this scoring system but it should not be a substitute for measurement of material loss. PMID:24411082

Hothi, Harry S; Matthies, Ashley K; Berber, Reshid; Whittaker, Robert K; Skinner, John A; Hart, Alister J

2014-06-01

77

Rationale for one stage exchange of infected hip replacement using uncemented implants and antibiotic impregnated bone graft  

Microsoft Academic Search

Infection of a total hip replacement (THR) is considered a devastating complication, necessitating its complete removal and thorough debridement of the site. It is undoubted that one stage ex- change, if successful, would provide the best benefit both for the patient and the society. Still the fear of re-infection dominates the surgeonsdecisions and in the majority of cases directs them

Heinz Winkler

2009-01-01

78

Locking Compression Plates for the Treatment of Periprosthetic Femoral Fractures Around Well-Fixed Total Hip and Knee Implants  

Microsoft Academic Search

There are currently few published studies examining the use of locking compression plates for the treatment of periprosthetic femoral fractures. Fifteen total hip or knee arthroplasty patients with 16 Vancouver type B1 and C fractures with an average age of 76 years were fixed and followed clinically and radiographically for 2 years. Fourteen patients achieved radiographic union by 6 months,

Gavin C. A. Wood; Doug R. Naudie; James McAuley; Richard W. McCalden

2011-01-01

79

Antibiotic prophylaxis in total hip arthroplasty  

Microsoft Academic Search

We have assessed the effect of different regimes of antibiotic prophylaxis on the survival of total hip implants, comparing antibiotics administered both systemically and in the bone cement, systemically only, in the bone cement only and with no antibiotics given. We studied 10 905 primary cemented total hip replacements, performed for osteoarthritis of the hip and reported to the Norwegian

B. Espehaug; L. B. Engesaeter; S. E. Vollset; L. I. Havelin; N. Langeland

1997-01-01

80

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

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

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

2013-01-01

81

Hip contact forces and gait patterns from routine activities  

Microsoft Academic Search

In vivo loads acting at the hip joint have so far only been measured in few patients and without detailed documentation of gait data. Such information is required to test and improve wear, strength and fixation stability of hip implants. Measurements of hip contact forces with instrumented implants and synchronous analyses of gait patterns and ground reaction forces were performed

G Bergmann; G Deuretzbacher; M Heller; F Graichen; A Rohlmann; J Strauss; G. N Duda

2001-01-01

82

(v) Prevention of dislocation in hip arthroplasty  

Microsoft Academic Search

Dislocation following primary and revision hip surgery is a common complication. The cause is often multi-factorial including patient factors, surgeon factors, implant design, implant orientation, and soft tissue factors. This article looks at ways of reducing the rate of hip dislocation.

S. W. Veitch; S. A. Jones

2009-01-01

83

Eleven-year results of the ABG I hip replacement  

Microsoft Academic Search

The ABG I uncemented hip prosthesis has demonstrated an unacceptably high failure rate and poor functional outcome in our patients. A prospective review was performed of 38 implanted hips with a mean follow-up of 11 years. Sixteen hips have been revised or are candidates for revision hip surgery, due principally to polyethylene wear and pelvic osteolysis. Contributing factors were likely

W. Y. Kim; B. N. Muddu

2006-01-01

84

Metal on metal hip resurfacing arthroplasty  

Microsoft Academic Search

This paper explores the cost utility of metalon-metal hip resurfacing arthroplasty (MOM) as an alternative intervention to\\u000a total hip replacement or ‘watchful waiting’ for patients with advanced hip disease. Early implant failure among younger and\\u000a more active elderly patients can mean that the use of total hip replacement (THR) is delayed, with patients managed through\\u000a ‘watchful waiting’, a combination of

L. McKenzie; L. Vale; S. Stearns; K. McCormack

2003-01-01

85

Cement augmentation of hip implants in osteoporotic bone: how much cement is needed and where should it go?  

PubMed

Several studies proved the beneficial effect of cement augmentation of proximal femoral nail antirotation (PFNA) blades on implant purchase in osteoporotic bone. We investigated the effect of different localizations and amounts of bone cement. Polyurethane foam specimens were instrumented with a PFNA blade and subsequently augmented with PMMA bone cement. Eight study groups were formed based on localization and amount of cement volume related to the blade. All specimens underwent cyclic loading with physiological orientation of the force vector until construct failure. Foam groups were compared between each other and to a cadaveric control group. The experiments revealed a significant dependency of implant purchase on localization and amount of cement. Biomechanically favorable cement positions were found at the implant tip and at the cranial side. However, none of the tested augmentation patterns performed significantly inferior to the cadaveric benchmark. These findings will allow surgeons to further reduce the amount of injected PMMA, decreasing the risk of cement leakage or cartilage damage. PMID:24259367

Sermon, A; Hofmann-Fliri, L; Richards, R G; Flamaing, J; Windolf, M

2014-03-01

86

Spacer-related problems in two-stage revision knee arthroplasty.  

PubMed

Although articulated cement spacers are frequently used in a staged approach of an infected total knee arthroplasty (TKA), no data are available on the incidence and type of spacer-related problems in these patients. A retrospective analysis of 154 patients who underwent a two-stage revision procedure for an infected TKA was performed. All patients received an articulating cement spacer at the implant removal procedure; their radiographs were analyzed for spacer-related issues such as spacer dislocation, fracture, tilting or translation, and knee subluxation. In 43% of the patients, the spacer was considered as optimal. The main finding of this study is the large incidence (57%) of spacer-specific problems in two-stage revision knee arthroplasty for infected TKA. Spacer tilting and mediolateral translation were found to be the most frequent spacer-specific problems, in 24% and 21% of the cases respectively. These were considered as minor problems. Major problems were seen in 12 % : in 3% of the knees the spacer had dislocated, in 5% the spacer fractured and in 4%, although the spacer seemed to be adequately positioned relative to the femoral and tibial bone, frank knee subluxation could be noted. The impact of spacer-specific problems with articulating cement spacers on final outcome in two-stage revision knee surgery will be further investigated. PMID:24205773

Struelens, Bernard; Claes, Steven; Bellemans, Johan

2013-08-01

87

What are the predictors for bead shedding in porous-coated hip and knee arthroplasties?: An implant retrieval study.  

PubMed

Bead shedding has been reported in both hip and knee arthroplasties and can result in increased polyethylene wear and metal ion release. The rates of bead loss were recorded for each device type, and the interfacial bead-substrate shear load to failure and contact areas of the beads were determined. The 3 components with the highest rate of bead loss, namely, S-Rom, Omnifit, and Optifix acetabular shells, recorded the lowest shear loads to failure. Percentage bead-substrate contact area ranged between 7% and 37% and was the most important factor affecting bead shedding. Other factors influencing bead loss in decreasing order of importance were bead fusion, bead size, component type (acetabular or knee), component loosening, and time in situ. PMID:22770858

Swarts, Eric; Kop, Alan M; Phillips, Michael

2012-12-01

88

Septic versus aseptic hip revision: how different?  

Microsoft Academic Search

Background  The few available studies directly comparing aseptic and septic joint revision surgery report conflicting results. We investigated\\u000a whether two-stage revision of septic hip prosthesis with a preformed antibiotic-loaded spacer and an uncemented prosthesis\\u000a provides hip function and quality of life similar to those provided by aseptic revision surgery in the medium term, as well\\u000a as the associated direct hospital costs.

Carlo Luca Romanò; Delia Romanò; Nicola Logoluso; Enzo Meani

2010-01-01

89

Patient and implant survival following 4323 total hip replacements for acute femoral neck fracture: a retrospective cohort study using National Joint Registry data.  

PubMed

United Kingdom National Institute for Health and Clinical Excellence guidelines recommend the use of total hip replacement (THR) for displaced intracapsular fractures of the femoral neck in cognitively intact patients, who were independently mobile prior to the injury. This study aimed to analyse the risk factors associated with revision of the implant and mortality following THR, and to quantify risk. National Joint Registry data recording a THR performed for acute fracture of the femoral neck between 2003 and 2010 were analysed. Cox proportional hazards models were used to investigate the extent to which risk of revision was related to specific covariates. Multivariable logistic regression was used to analyse factors affecting peri-operative mortality (< 90 days). A total of 4323 procedures were studied. There were 80 patients who had undergone revision surgery at the time of censoring (five-year revision rate 3.25%, 95% confidence interval 2.44 to 4.07) and 137 patients (3.2%) patients died within 90 days. After adjusting for patient and surgeon characteristics, an increased risk of revision was associated with the use of cementless prostheses compared with cemented (hazard ratio (HR) 1.33, p = 0.021). Revision was independent of bearing surface and head size. The risk of mortality within 90 days was significantly increased with higher American Society of Anesthesiologists (ASA) grade (grade 3: odds ratio (OR) 4.04, p < 0.001; grade 4/5: OR 20.26, p < 0.001; both compared with grades 1/2) and older age (? 75 years: OR 1.65, p = 0.025), but reduced over the study period (9% relative risk reduction per year). THR is a good option in patients aged < 75 years and with ASA 1/2. Cementation of the femoral component does not adversely affect peri-operative mortality but improves survival of the implant in the mid-term when compared with cementless femoral components. There are no benefits of using head sizes > 28 mm or bearings other than metal-on-polyethylene. More research is required to determine the benefits of THR over hemiarthroplasty in older patients and those with ASA grades > 2. PMID:23109639

Jameson, S S; Kyle, J; Baker, P N; Mason, J; Deehan, D J; McMurtry, I A; Reed, M R

2012-11-01

90

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

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

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

2014-01-01

91

Exeter total hip arthroplasty with matte or polished stems  

Microsoft Academic Search

Summary. Objective. To compare implant survival rates after total hip arthroplasty with Exeter matte or polished stems and to determine the relationship of synovitis\\/joint effusion to signs of implant loosening and stem type. Material and methods. The first part of the study included retrospective revision rate analysis of 118 primary hip replacements performed during 1991-1995. Two different designs of Exeter

Alfredas Smailys; Uldis Kesteris; Romas Jonas Kalesinskas; Hans Wingstrand

92

Does surgical approach influence component positioning with Birmingham Hip Resurfacing?  

Microsoft Academic Search

The aim of this study was to compare the component positioning of Birmingham Hip Resurfacings implanted through a posterolateral\\u000a approach with those inserted via a direct lateral approach. Sixty-four hip resurfacings for osteoarthritis were carried out\\u000a by a single surgeon: 23 through a direct lateral approach and 41 through a posterolateral approach. No significant differences\\u000a in implant survival, Oxford Hip

G. J. C. Myers; D. Morgan; C. W. McBryde; K. O’Dwyer

2009-01-01

93

Two-year migration results of the ReCap hip resurfacing system—a radiostereometric follow-up study of 23 hips  

Microsoft Academic Search

There has been renewed interest for metal-on-metal hip resurfacing due to improved design and manufacturing of implants, better\\u000a materials, and enhanced implant fixation. In contrast to conventional total hip replacements, only a few clinical hip resurfacing\\u000a trials using radiostereometry (RSA) have been reported, and solely for the Birmingham hip resurfacing arthroplasty. The purpose\\u000a of this RSA trial was to describe

Thomas Baad-Hansen; Stig Storgaard Jakobsen; Kjeld Soballe

2011-01-01

94

Enhanced Stability of Total Hip Replacement Implants Resulting from Use of an Elevated-Rim Acetabular Liner and 32-mm Femoral Head  

Microsoft Academic Search

The use of an elevated-rim acetabular liner in total hip arthroplasty (THA) is widely accepted. We sought to determine quantitatively the amount of additional stability provided by the elevated-rim liner as compared to the standard non-elevated liner. Furthermore, the stability of the hip with a 32-mm femoral head was compared to the standard 28-mm head. Our results show that a

P. G. SULTAN; V. TAN; M. LAI; J. P. GARINO

95

Hip Replacement  

MedlinePLUS

... you experience any of these symptoms. When Is Revision Surgery Necessary? Hip replacement is one of the most successful orthopaedic ... show damage to the bone around the artificial hip that must be corrected ... revision. This surgery is usually considered only when bone loss, wearing ...

96

Subacromial Spacer Placement for Protection of Rotator Cuff Repair  

PubMed Central

Rotator cuff repairs have a high failure rate proportional to the tear size. Various techniques have been described to improve the repair strength and failure rate. The described surgical technique uses a biodegradable subacromial balloon-shaped spacer (InSpace; OrthoSpace, Caesarea, Israel) that is implanted arthroscopically to protect our tendon repair. We describe the introduction technique and suggest some hints and tricks. The spacer is placed under direct vision in the subacromial space after the rotator cuff repair is finished. Correct placement is verified by moving the arm freely. The subacromial spacer may help to protect the rotator cuff repair by centering the humeral head and reducing friction between suture knots and the acromion. It may also help to flatten dog-ear formations. PMID:25473615

Szöllösy, Gregor; Rosso, Claudio; Fogerty, Simon; Petkin, Kalojan; Lafosse, Laurent

2014-01-01

97

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: A study using the NJR dataset.  

PubMed

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 67 045 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:10-18. PMID:25568407

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

2015-01-01

98

The UniSpacer™: correcting varus malalignment in medial gonarthrosis.  

PubMed

While options for operative treatment of leg axis varus malalignment in patients with medial gonarthrosis include several established procedures, such as unicompartmental knee arthroplasty (UKA), total knee arthroplasty (TKA) or high tibial osteotomy (HTO), there has been little focus on a less invasive option introduced more recently: the UniSpacerimplant, a self-centering, metallic interpositional device for the knee. This study evaluates clinical and radiological results of the UniSpacer™, whether alignment correction can be achieved by UniSpacer™ arthroplasty and alignment change in the first five postoperative years. Anteroposterior long leg stance radiographs of 20 legs were digitally analysed to assess alignment change: two relevant angles and the deviation of the mechanical axis of the leg were analysed before and after surgery. Additionally, the change of the postoperative alignment was determined one and five years postoperatively. Analysing the mechanical tibiofemoral angle, a significant leg axis correction was achieved, with a mean valgus change of 4.7?±?1.9°; a varus change occurred in the first postoperative year, while there was no significant further change of alignment seen five years after surgery. The UniSpacer™ corrects malalignment in patients with medial gonarthrosis; however, a likely postoperative change in alignment due to implant adaptation to the joint must be considered before implantation. Our results show that good clinical and functional results can be achieved after UniSpacer™ arthroplasty. However, four of 19 knees had to be revised to a TKA or UKA due to persistent pain, which is an unacceptably high revision rate when looking at the alternative treatment options of medial osteoarthritis of the knee. PMID:19946773

Clarius, Michael; Becker, Justus F; Schmitt, Holger; Seeger, Joern B

2010-12-01

99

The UniSpacer™: correcting varus malalignment in medial gonarthrosis  

PubMed Central

While options for operative treatment of leg axis varus malalignment in patients with medial gonarthrosis include several established procedures, such as unicompartmental knee arthroplasty (UKA), total knee arthroplasty (TKA) or high tibial osteotomy (HTO), there has been little focus on a less invasive option introduced more recently: the UniSpacerimplant, a self-centering, metallic interpositional device for the knee. This study evaluates clinical and radiological results of the UniSpacer™, whether alignment correction can be achieved by UniSpacer™ arthroplasty and alignment change in the first five postoperative years. Anteroposterior long leg stance radiographs of 20 legs were digitally analysed to assess alignment change: two relevant angles and the deviation of the mechanical axis of the leg were analysed before and after surgery. Additionally, the change of the postoperative alignment was determined one and five years postoperatively. Analysing the mechanical tibiofemoral angle, a significant leg axis correction was achieved, with a mean valgus change of 4.7?±?1.9°; a varus change occurred in the first postoperative year, while there was no significant further change of alignment seen five years after surgery. The UniSpacer™ corrects malalignment in patients with medial gonarthrosis; however, a likely postoperative change in alignment due to implant adaptation to the joint must be considered before implantation. Our results show that good clinical and functional results can be achieved after UniSpacer™ arthroplasty. However, four of 19 knees had to be revised to a TKA or UKA due to persistent pain, which is an unacceptably high revision rate when looking at the alternative treatment options of medial osteoarthritis of the knee. PMID:19946773

Becker, Justus F.; Schmitt, Holger; Seeger, Joern B.

2009-01-01

100

Biotribology of artificial hip joints.  

PubMed

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

Di Puccio, Francesca; Mattei, Lorenza

2015-01-18

101

Biotribology of artificial hip joints  

PubMed Central

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.

Di Puccio, Francesca; Mattei, Lorenza

2015-01-01

102

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

PubMed

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 15weeks (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

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

2015-02-01

103

An objective examination for painful hip after total hip arthroplasty.  

PubMed

An objective method for evaluating the cause of pain in hip arthroplasty was investigated in patients with a radiolucent zone of less than 2 mm at the cement-bone interface or the cement-stem or socket interface. Eight patients with a McKee-Farrar total hip prosthesis followed up for an average of 102 months and 20 patients with a Charnley total hip prosthesis observed for an average of 43 months were studied. Different components of the implant materials, such as cement monomer, BaSO4, ceramic, acrylic cement, stainless steel and high-density polyethylene, (HDP) were exposed to normal plasma. Contact activation of plasma was found to occur for all materials, except for HDP, yielding plasma kallikrein. The induced prekallikrein activation was markedly reduced in vitro by Trasylol. There was a significant increase in plasma kallikrein activity in the patients with discomfort and/or pain without gross loosening compared with the patients with pain-free hip arthroplasties. Furthermore, statistically significant enhancement of the kallikrein activity was observed in plasma from the femoral vein at the site of operation compared with that from the cubital vein of the same subject. The enhanced plasma kallikrein activity in the patients gradually decreased, as did the clinical symptoms, when Trasylol was administered. It is concluded that measurement of plasma kallikrein activity may produce useful information about the process of total hip arthroplasty and provide an objective evaluation of pain. PMID:6179385

Nakahara, M

1982-08-01

104

Surface replacement of the hip.  

PubMed

Attempts to resurface the hip joint date back to the 1930s. Throughout the last century many designs failed due to defective materials or fixation (or a combination). The metal-on-metal designs pioneered at the end of the century appeared to herald a new era, until difficulties associated with adverse reactions to metal debris were identified. Ultimately, a much narrower range of indications emerged - large, young males appear to be the ideal recipients. Implant design features and component orientation are crucial to the survivorship of these implants. PMID:25329979

Spencer, Robert F

2014-01-01

105

Three-dimensional dynamic hip contact area and pressure distribution during activities of daily living  

Microsoft Academic Search

Estimation of the hip joint contact area and pressure distribution during activities of daily living is important in predicting joint degeneration mechanism, prosthetic implant wear, providing biomechanical rationales for preoperative planning and postoperative rehabilitation. These biomechanical data were estimated utilizing a generic hip model, the Discrete Element Analysis technique, and the in vivo hip joint contact force data. The three-dimensional

H. Yoshida; A. Faust; J. Wilckens; M. Kitagawa; J. Fetto; Edmund Y.-S. Chao

2006-01-01

106

Management of total femoral bone loss using a hybrid cement spacer surgical technique.  

PubMed

Standard treatment for an infected total hip arthroplasty is 2-stage revision. Bone loss in infected total hip arthroplasty presents specific challenges during the first stage. This is especially the case when there is massive or complete loss of the femoral bone stock. We describe a technique successfully used in the setting of total femoral bone loss using a hybrid cement spacer. We describe 2 cases illustrating the technique and perioperative course. This technique is a potential solution for total femoral bone loss that allows the individual to maintain mobility before definitive surgery. PMID:22749006

Cassar Gheiti, Adrian J; Baker, Joseph F; Brown, Thomas E; Mulhall, Kevin J

2013-02-01

107

Hip joints  

NSDL National Science Digital Library

The human hips are an example of a ball-and-socket joint. Ball-and-socket joints have the ability to rotate in a circular motion. The joint where the arm connects to the shoulder is also a type of ball-and-socket joint.

Connie Raab (National Institutes of Health;)

2006-05-17

108

Hip Replacement  

MedlinePLUS

... a product containing both acetaminophen and a narcotic codeine to control pain. For inflammation, doctors may prescribe corticosteroids; however, they should not be used any longer than necessary because of their harmful side effects. Hip Replacement Isn't for Everyone For example, ...

109

Lag screws for hip fracture fixation: Evaluation of migration resistance under simulated walking  

Microsoft Academic Search

Previous mechanical studies concerning cut-out of lag screws for pertrochanteric hip fractures have relied on static or dynamic uniaxial loading regimens to induce construct failure by varus collapse and superior cut-out. However, the hip is loaded in a mul- tiplanar, dynamic manner during normal gait. We designed a hip implant performance simulator (HIPS) system to evaluate lag screw cut-out under

Larry W. Ehmke; Daniel C. Fitzpatrick; James C. Krieg; Steven M. Madey; Michael Bottlang

2005-01-01

110

Anti-spacer double patterning  

NASA Astrophysics Data System (ADS)

With extreme UV not ready for HVM for the 20nm and 14nm nodes, double patterning options that extend the use of 193nm immersion lithography beyond the optical resolution limits, such as LELE (Litho-Etch-Litho-Etch) and SADP (Self Aligned Double Patterning), are being used for critical layers for these nodes. LELE requires very stringent overlay capability of the optical exposure tool. The spacer scheme of SADP starts with a conformal film of material around the mandrels and etched along the mandrel sidewalls to form patterns with doubled frequency. SADP, while having the advantage of being a self-aligned process, adds a number of process steps and strict control of the mandrel profile is required. In this paper, we will demonstrate a novel technique - ASDP (Anti-Spacer Double Patterning), which uses only spin-on materials to achieve self-aligned double patterning. After initial resist patterning, an Anti-Spacer Generator (ASG) material is coated on the resist pattern to create the developable spacer region. Another layer of material is then coated and processed to generate the second pattern in between the first resist pattern. We were able to define 37.5nm half pitch pattern features using this technique as well as sub-resolution features for an asymmetric pattern. In this paper we will review the capability of the process in terms of CD control and LWR (line width roughness) and discuss the limitations of the process.

Hyatt, Michael; Huang, Karen; DeVilliers, Anton; Slezak, Mark; Liu, Zhi

2014-03-01

111

Complex primary total hip arthroplasty.  

PubMed

Although total hip arthroplasty is now a classic procedure that is well controlled by orthopedic surgeons, some cases remain complex. Difficulties may be due to co-morbidities: obesity, skin problems, muscular problems, a history of neurological disease or associated morphological bone deformities. Obese patients must be informed of their specific risks and a surgical approach must be used that obtains maximum exposure. Healing of incisions is not a particular problem, but adhesions must be assessed. Neurological diseases may require tenotomy and the use of implants that limit instability. Specific techniques or implants are necessary to respect hip biomechanics (offset, neck-shaft angle) in case of a large lever arm or coxa vara. In case of arthrodesis, before THA can be performed, the risk of infection must be specifically evaluated if the etiology is infection, and the strength of the gluteal muscles must be determined. Congenital hip dysplasia presents three problems: the position and coverage of the cup, placement of a specific or custom made femoral stem, with an osteotomy if necessary, and finally lowering the femoral head into the cup by freeing the soft tissues or a shortening osteotomy. Acetabular dysplasia should not be underestimated in the presence of significant bone defect (BD), and reconstruction with a bone graft can be proposed. Sequelae from acetabular fractures presents a problem of associated BD. Internal fixation hardware is rarely an obstacle but the surgical approach should take this into account. Treatment of acetabular protrusio should restore a normal center of rotation, and prevent recurrent progressive protrusion. The use of bone grafts and reinforcement rings are indispensible. Femoral deformities may be congenital or secondary to trauma or osteotomy. They must be evaluated to restore hip biomechanics that are as close to normal as possible. Fixation of implants should restore anteversion, length and the lever arm. Most problems that can make THA a difficult procedure may be anticipated with proper understanding of the case and thorough preoperative planning. PMID:23375960

Boisgard, S; Descamps, S; Bouillet, B

2013-02-01

112

Metal-on-Metal Total Hip Resurfacing Arthroplasty  

PubMed Central

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 r

2006-01-01

113

Results of total hip arthroplasty in patients who have rapidly progressive hip disease: a systematic review of the literature.  

PubMed

Rapidly progressive hip disease is a rare condition characterized by rapid joint space narrowing (>2 mm in 1 year), chondrolysis and destruction of the femoral head. Although the etiology and pathogenetic mechanism is unclear, subchondral insufficiency fractures in the setting of physiologically weakened bone has recently been implicated as the primary insult. The standard of care has been total hip arthroplasty; however, there is a theoretical risk that the disease process may continue, placing the prosthesis at risk. In order to determine the clinical outcomes and implant survivorship in this population, a systematic search of the literature was conducted. Midterm (mean: 5 years) results following total hip arthroplasty demonstrated mean good-to-excellent clinical results (clinical hip scores >80 points) and a 3% revision rate, making this a valuable treatment option for patients who have rapidly progressive hip disease. The underlying disease process does not appear to compromise implant longevity. PMID:22702256

Pivec, Robert; Johnson, Aaron J; Mont, Michael A

2012-05-01

114

Spacer grid assembly and locking mechanism  

DOEpatents

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.

Snyder, Jr., Harold J. (Rancho Santa Fe, CA); Veca, Anthony R. (San Diego, CA); Donck, Harry A. (San Diego, CA)

1982-01-01

115

Generator stator core vent duct spacer posts  

DOEpatents

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.

Griffith, John Wesley (Schenectady, NY); Tong, Wei (Clifton Park, NY)

2003-06-24

116

How to read a postoperative total hip replacement radiograph  

Microsoft Academic Search

In 2006 over 55 000 primary total hip replacements were implanted in the UK. A crucial aspect of follow-up for these patients is the assessment of the postoperative radiograph. Information gained from the initial radiograph includes assessment of the quality of implantation and hence the likelihood of long term success. Follow-up radiographs can be assessed for signs of component failure.

Tim J McBride; Divya Prakash

2010-01-01

117

Two Stage Hip Revision in Periprosthetic Infection: Results of 41 Cases  

PubMed Central

Background: two-stage revision is considered the best treatment approach for the eradication of chronic joint infection. We report the outcome of 41 consecutive patients with infected hip prostheses, treated between 2000 and 2005, with two-stage revision using an antibiotic-loaded cement spacer. Methods: Patients underwent a treatment protocol which included clinical and radiographic evaluation, laboratory investigations, hip aspiration, 99mTc-MDP and 99mTc-leukocyte-labeled scintigraphy and intraoperative assessment. All patients were diagnosed with a late chronic infection and classified as B-host according to the Cierny-Mader classification system. 9 patients out of 41 (22%) required a second interim treatment period, with exchange of the spacer. The proportion of methicillin-resistant Staphylococcus was similar between the one-spacer group and two-spacer group (28% vs 33%), whereas the proportion of patients with three or more risk factors was significantly higher in the two-spacer group than in the one-spacer group (28% vs 55%, respectively). Results: Forty patients had final reimplantation, one patient had a resection arthroplasty. At an average follow-up of 5.3 years no recurrence of infection occurred. The average post-operative Harris hip score improved from 41 to 80. Conclusions: In the treatment of two-stage revision arthroplasty the adherence to the protocol proved to be effective for infection eradication and final reimplantation. PMID:20721319

Pignatti, Giovanni; Nitta, Shingo; Rani, Nicola; Dallari, Dante; Sabbioni, Giacomo; Stagni, Cesare; Giunti, Armando

2010-01-01

118

Revision Hip Arthroscopy  

Microsoft Academic Search

Background: Hip arthroscopy has become increasingly popular; however, little is known about revision hip arthroscopy.Hypothesis: Revision hip arthroscopy is associated with unaddressed femoroacetabular impingement. The purpose of this study was to describe reasons for revision hip arthroscopy.Study Design: Case series; Level of evidence, 4.Methods: Between March 2005 and March 2006, 37 revision hip arthroscopies were performed by the senior author.

Marc J. Philippon; Mara L. Schenker; Karen K. Briggs; David A. Kuppersmith; R. Brian Maxwell; Allston J. Stubbs

2007-01-01

119

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

PubMed

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

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

1980-01-01

120

Biomechanics of the Birmingham hip resurfacing arthroplasty.  

PubMed

The effects of the method of fixation and interface conditions on the biomechanics of the femoral component of the Birmingham hip resurfacing arthroplasty were examined using a highly detailed three-dimensional computer model of the hip. Stresses and strains in the proximal femur were compared for the natural femur and for the femur resurfaced with the Birmingham hip resurfacing. A comparison of cemented versus uncemented fixation showed no advantage of either with regard to bone loading. When the Birmingham hip resurfacing femoral component was fixed to bone, proximal femoral stresses and strains were non-physiological. Bone resorption was predicted in the inferomedial and superolateral bone within the Birmingham hip resurfacing shell. Resorption was limited to the superolateral region when the stem was not fixed. The increased bone strain observed adjacent to the distal stem should stimulate an increase in bone density at that location. The remodelling of bone seen during revision of failed Birmingham hip resurfacing implants appears to be consistent with the predictions of our finite element analysis. PMID:16877617

Ong, K L; Kurtz, S M; Manley, M T; Rushton, N; Mohammed, N A; Field, R E

2006-08-01

121

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

NASA Astrophysics Data System (ADS)

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.

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

2013-02-01

122

Scatterometry characterization of spacer double patterning structures  

NASA Astrophysics Data System (ADS)

DPT overlay errors result in CD distortions and CD non-uniformity leads to overlay errors demanding increased critical dimension uniformity (CDU) and improved overlay control. Scatterometry techniques are used to characterize the CD uniformity, focus and dose control. We will present CD distribution (CDU) and profile characterization for spacer double patterning structures by advanced scatterometry methods. Our result will include NISR, and spectroscopic ellipsometry (SE) characterization of CDU sensitivity in spacer double patterning stack. We will further show the results of spacer DP structures by NISR and SE measurements. Metrology comparison at various process steps including litho, etch and spacer and validation of CDU and profile; all benchmarked against traditional CDSEM measurements.

Dasari, Prasad; Hu, Jiangtao; Liu, Zhuan; Tan, Asher; Kritsun, Oleg; Volkman, Catherine; Bencher, Chris

2010-03-01

123

Chondrolysis after hip arthroscopy.  

PubMed

We report the case of a 58-year-old woman who presented with left hip pain and was diagnosed with femoroacetabular impingement. She underwent hip arthroscopy to repair a degenerative labral tear, as well as radiofrequency debridement and microfracture of the exposed chondral defect, and femoral osteoplasty. Two months after hip arthroscopy, hip pain and limping began. Hip radiography showed a concentric decrease of joint space and no signs of joint incongruity or osteophytosis. Revision surgery 4 months after hip arthroscopy showed that the cartilage of the femoral head was soft and separated from the subchondral bone. PMID:25218006

Más Martínez, Jesús; Sanz Reig, Javier; Morales Santias, Manuel; Bustamante Suarez de Puga, David

2015-01-01

124

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

Microsoft Academic Search

Background  Femoral offset influences the forces at the hip and the implant stresses after revision THR. For extended bone defects, these\\u000a forces may cause considerable bending moments within the implant, possibly leading to implant failure. This study investigates\\u000a the influences of femoral anteversion and offset on stresses in the Wagner SL revision stem implant under varying extents\\u000a of bone defect conditions.

Markus O Heller; Manav Mehta; William R Taylor; Dong-Yeong Kim; Andrew Speirs; Georg N Duda; Carsten Perka

2011-01-01

125

Cardiovascular Effects of Implanted Acrylic Bone Cement  

Microsoft Academic Search

A pilot study has shown that there is usually but not invariably a fall in systemic arterial blood pressure within 90 seconds of implanting acrylic cement into the femoral shaft during hip arthroplasty. There is usually no change in arterial blood pressure on implanting acrylic cement into the acetabulum. The observed hypotension may be due to absorption of monomer or

Hugh Phillips; Peter V. Cole; Alan W. F. Lettin

1971-01-01

126

Transfemoral implantation of the Wagner SL stem  

Microsoft Academic Search

Background. The Wagner SL uncemented revision stem has been utilised successfully for revision hip surgery where marked loss of proximal bone stock co-exists or where there is a periprosthetic fracture. Implanted via the transfemoral approach, one significant difficulty appears to be a tendency for implant subsidence, which in some cases has been troublesome enough to necessitate early revision (usually to

P. J. Warren; P. Thompson; M. D. A. Fletcher

2002-01-01

127

Total Hip Replacement  

MedlinePLUS

... as running, jogging, jumping, or other high-impact sports. Realistic activities following total hip replacement include unlimited ... driving, hiking, biking, dancing, and other low-impact sports. With appropriate activity modi? cation, hip replacements can ...

128

Computer assisted hip surgery by using modular-neck femoral component: principles, technique, advantages and limits  

Microsoft Academic Search

The author describes the use of a CT-free navigation system equipped with a software, specifically designed to improve the\\u000a implantation of a modular-neck anatomic cementless stem and acetabular cup for Total Hip Replacement (THR). When comparing\\u000a the anatomic parameters measured intraoperatively with the native hip and the prosthetic hip, it appears that the use of the\\u000a modular-neck allows a better

P. Merloz

2008-01-01

129

The Biomet Bi-Metric Total Hip Arthroplasty and Universal Acetabular Cup  

Microsoft Academic Search

We report on the medium-term results of the Bi-Metric (Biomet UK Ltd, Bridgend, UK) uncemented total hip arthroplasty system used with the Universal acetabular cup and polyethylene liner secured with the Ringloc (Biomet UK Ltd) mechanism. Fifty-eight total hip arthroplasties in 49 patients (mean age at implantation, 57.1 years) were identified, with 45 hips followed up at a mean of

David Llewellyn Isaac; Justin Forder; Andrew D. Skyrme; Stephen E. James

2007-01-01

130

Investigation of hip joint prosthesis damage.  

PubMed

Following total hip arthroplasty the durability of a prosthetic implant depends on many factors but is generally limited by two types of damage: wearing of frictional surfaces of the acetabular and femoral component as well as the loosening and migration of the "rosthesis-cement-bone" system. Since it is possible to establish a cause-and-effect relationship between these two damage types, the aim of this research is to investigate the phenomena related to the contact surface and their influence on the prosthesis-bone relationship in general for various sizes and conditions of loading of the hip joint. The experimental study was conducted using a Timken testing device modified in such a way that simulation of relative movements of the joint elements was achieved using a mechanism that produces conditions similar to those in the human hip joint. The analysis of obtained measurements showed that actual radii of friction of the hip prosthesis did not correspond to the theoretical ones and that only a small portion of the total friction surface is realized. Variations of the radius of friction for the examined prosthesis type were very large, which changes the hypotheses on the ability of the prosthetic head and the "prosthesis-cement-bone" system to bear a certain amount of load. The construction and design of prosthetic implant components has a significant influence on both the amount of wear at the site of contact and the loosening of prosthesis. PMID:11787549

Bajs, I D; Sari?, V; Opali?, M

2001-06-01

131

Rare fracture of a total hip replacement.  

PubMed

Material fractures in the femoral part of total hip replacements, a late complication, are usually observed in the shaft. In our case, a fatigue fracture of the ball-neck weld occurred 8 1/2 years after implantation of the prosthesis because of insufficient weld depth. Additional negative factors proved to be varus implantation and overloading of the prosthesis due to obesity. The weld represented a point of low resistance. Even if major traumatic events are responsible for the fracture or loosening of an endoprosthesis, overloading (i.e., multiple "microtrauma") is also an important contributing factor. PMID:6870507

Aldinger, G; Mitzkat, K

1983-01-01

132

Why Revision Total Hip Arthroplasty Fails  

Microsoft Academic Search

Current outcomes data on revision total hip arthroplasty focuses on specific implants and techniques rather than more general\\u000a outcomes. We therefore examined a large consecutive series of failed THAs undergoing revision to determine if survivorship\\u000a and modes of failure differ in comparison to the current data. We retrospectively reviewed the medical records of 1100 revision\\u000a THAs. The minimum followup was

Bryan D. Springer; Thomas K. Fehring; William L. Griffin; Susan M. Odum; John L. Masonis

2009-01-01

133

Influence of shoes and heel strike on the loading of the hip joint  

Microsoft Academic Search

The forces and moments acting at the hip joint influence the long-term stability of the fixation of endoprostheses and the course of coxarthrosis. These loads may depend on the kind of footwear and the walking or running style. These factors were investigated in a patient with instrumented hip implants. He wore different sports shoes, normal leather shoes, hiking boots and

G. Bergmann; H. Kniggendorf; F. Graichen; A. Rohlmann

1995-01-01

134

Metal-on-Metal Hip Resurfacing Arthroplasty  

PubMed Central

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

Sehatzadeh, S; Kaulback, K; Levin, L

2012-01-01

135

Probabilistic models for CRISPR spacer content evolution  

PubMed Central

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

2013-01-01

136

Hip arthroplasty for failed treatment of proximal femoral fractures.  

PubMed

Failed treatment of an intertrochanteric fracture typically leads to profound functional disability and pain. Salvage treatment with hip arthroplasty may be considered. The aim of this study was to evaluate the results and complications of hip arthroplasty performed as a salvage procedure after the failed treatment of an intertrochanteric hip fracture. Twenty-one patients were treated in our hospital with hip arthroplasty for failed treatment of intertrochanteric hip fracture. There were sixteen women and five men with a mean age of 75.8 years (range 61-85 years). Fourteen patients had failure of a previous nail fixation procedure, five had failure of a plate fixation, one of hip screws fixation and one of Ender nail fixation. In 19 out of 21 patients we performed a total hip arthroplasty-14 cases used modular implants with long-stems and five cases used a standard straight stem. In 2 of 21 cases we used a bipolar hemiarthroplasty. A statistically significant improvement was found comparing pre and postoperative conditions (p < 0.05). Our experience confirms that total hip arthroplasty is a satisfactory salvage procedure after failed treatment of an intertrochanteric fracture in elderly patients with few serious orthopaedic complications and acceptable clinical outcomes. PMID:19572131

D'Arrigo, Carmelo; Perugia, Dario; Carcangiu, Alessandro; Monaco, Edoardo; Speranza, Attilio; Ferretti, Andrea

2010-10-01

137

Revision total hip replacement without trochanteric osteotomy.  

PubMed

Revision total hip replacement has traditionally required a trochanteric osteotomy for successful cement removal and component reinsertion. In this study the authors have concluded that in most instances the revision total hip replacement procedure can be successfully performed without trochanteric osteotomy. The advantages are underscored by the high percentage of trochanteric complications with trochanteric osteotomy for revision total hip replacement and the ease of rehabilitation without trochanteric osteotomy. Also, improved functional results without trochanteric osteotomy were noted. The specific indications for the procedure included revision total hip replacement with ununited prior trochanteric osteotomy, revision total hip replacement with femoral shaft fractures, and revision total hip replacement with stem fractures requiring only acetabular revision. The contraindications to the procedure are fibrous union or ununited trochanteric osteotomy from prior total hip replacement, severe acetabular protrusion of the acetabular component, advanced myositis ossificans, ankylosis of the hip, and advanced proximal femoral osteoporosis. The operating room records, x-rays, and outpatient records of 63 total hip revisions in 52 patients were reviewed. There was a minimum 2-year follow up with a range from two years to seven years. The patients were divided into two groups, comparing 21 trochanteric osteotomized revisions to 44 with trochanteric sparing techniques. Both groups were analyzed for age, type of implant, intraoperative perforation of femur, intraoperative femoral shaft fractures, intraoperative cortical window, component malpositioning extraneous cement, intraoperative blood loss, operating time, postoperative leg length inequality, persistent abductor weakness, average first day of ambulation, wound infection, dislocation, nonunion of the trochanter, and postoperative pain. In the nonosteotomized group, there was a 21% decreased blood loss, a 14% decrease in persistent abductor weakness, a 14% decrease in subluxation and dislocation, a 30% decrease operating time and a 50% reduction in intraoperative femoral perforation. In the osteotomized group there were six cases of fibrous union of the greater trochanter, two cases requiring removal of broken wires for trochanteric bursitis. A detailed surgical technique and representative cases are presented. In carefully selected cases, revision total hip replacement is optimally performed without trochanteric osteotomy. Postoperative trochanteric problems of nonunion, broken wires, bursitis, and abductor weakness can effectively be eliminated by avoiding trochanteric osteotomy.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:3588421

Berman, A T; Salter, F L; Koenig, T

1987-05-01

138

Intervertebral test spacers and postfusion MRI artifacting: A comparative in vitro study of magnesium versus titanium and carbon fiber reinforced polymers as biomaterials  

Microsoft Academic Search

Intervertebral spacers are made of different materials, which can effect the postfusion magnetic imaging (MRI) scans. Susceptibility\\u000a artifacts specially for metallic implants can decrease the image quality. This study aimed to determine whether magnesium\\u000a as a lightweight and biocompatible metal is suitable as a biomaterial for spinal implants based on its MRI artifacting behavior.\\u000a To compare artifacting behaviors, we implanted

Thorsten Ernstberger; Gottfried Buchhorn; Gabert Heidrich

2009-01-01

139

The Artelon CMC spacer compared with tendon interposition arthroplasty  

PubMed Central

Background and purpose The Artelon CMC spacer is designed for surgical treatment of osteoarthritis (OA) in the carpometacarpal joint of the thumb (CMC-I). Good results using this degradable device were previously presented in a pilot study. We now present results from a larger randomized, controlled, multicenter study. Patients and methods 109 patients (94 females) with a mean age of 60 (42–83) years, suffering from painful CMC OA, were included in the study at 7 centers in Sweden. The patients were randomized to Artelon CMC spacer (test, n = 72) or tendon arthroplasty (control, n = 37) at a ratio of 2:1. Perceived pain was recorded on a visual analog scale (VAS) before treatment and after 3, 6, and 12 months, when measuring maximal tripod pinch strength (primary outcome measure). In addition, range of motion, radiographic findings, and functional testing were recorded pre- and postoperatively. Results Swelling and pain were more common in the test group and 6 implants were removed because of such symptoms. 5 of these patients did not receive antibiotics preoperatively according to the study protocol. In a per-protocol analysis, i.e. patients without signs of concomitant OA in the scaphoid-trapezium-trapezoid (STT) joint and those in the test group who received antibiotics, the mean difference in tripod pinch strength increase, adjusted for baseline, was 1.4 kg in favor of the test group (not statistically significant). Statistically significant pain relief was achieved in both groups, with perceived pain gradually decreasing during the follow-up period. In the intention-to-treat analysis but not in the per-protocol analysis, significantly better pain relief (VAS) was obtained in the control group. Patient-perceived disability evaluated by the DASH questionnaire improved in both groups. Interpretation The Artelon CMC spacer did not show superior results compared to tendon interposition arthroplasty. Proper use of preoperative antibiotics and a thorough patient selection appear to be important for the results. PMID:20180717

Wiig, Monica; Alnehill, Håkan; Berggren, Magnus; Björnum, Sten; Geijer, Mats; Kopylov, Philippe; Sollerman, Christer

2010-01-01

140

Mitral valve regurgitation and left ventricular dysfunction treatment with an intravalvular spacer.  

PubMed

Attempts at transcatheter treatment of mitral valve regurgitation have generally been modeled on proven surgical procedures such as leaflet repair, annuloplasty, or prosthetic valve implantation. We introduce a novel approach to directly reducing the regurgitant orifice: the mitral valve spacer, a balloon that attempts to reduce the regurgitant orifice. doi: 10.1111/jocs.12453 (J Card Surg 2015;30:53-54). PMID:25345652

Svensson, Lars G; Ye, Jian; Piemonte, Thomas C; Kirker-Head, Carl; Leon, Martin B; Webb, John G

2015-01-01

141

Migration analysis of a metaphyseal anchored short-stem hip prosthesis  

PubMed Central

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

2012-01-01

142

[The UniSpacer™: correcting varus malalignment in medial gonarthrosis. Preliminary results].  

PubMed

While options for operative treatment of leg axis varus malalignment in patients with medial gonarthrosis include several established procedures, such as unicompartmental knee arthroplasty (UKA), total knee arthroplasty (TKA), or high tibial osteotomy (HTO), so far there has been little focus on a less invasive option introduced more recently: the UniSpacerimplant, a modern, self-centering, metallic interpositional device for the knee. This study evaluates whether alignment correction can be achieved by UniSpacer™ arthroplasty as well as alignment change in the first 5 postoperative years is evaluated. Antero-posterior long leg stance radiographs of 15 legs were digitally analyzed to assess alignment change: two relevant angles and the deviation of the mechanical axis of the leg were analyzed before and after surgery. Additionally, the change of the postoperative alignment was determined one and five years postoperatively. Analyzing the mechanical tibiofemoral angle, a significant leg axis correction was achieved, with a mean valgus change of 4.7±1.9°; a varus change occurred in the first postoperative year, while there was no significant further change of alignment seen five years after surgery. The UniSpacer™ corrects malalignment in patients with medial gonarthrosis; however, a likely postoperative change in alignment due to implant adaptation to the joint must be considered before implantation. PMID:23594978

Seeger, J B; Cardenas-Montemayor, E; Becker, J F; Bischel, O; Röhner, E; Clarius, M

2013-01-01

143

Field Study of Offshore Cement-Spacer Mixing  

Microsoft Academic Search

Rheological data from cementing-spacer fluids are usually based on laboratory-prepared samples of the spacer and used to determine the flow rate required to provide the flow regime necessary for maximum efficiency of the spacer and to estimate the annular friction pressures associated with the spacer. Actual rheological properties are rarely measured on location, and the problems experienced with settling, foaming,

Glen Benge

1990-01-01

144

Inflammatory Pseudotumor Complicated by Recurrent Dislocations after Revision Total Hip Arthroplasty  

PubMed Central

A 71-year-old female with a history of right total hip arthroplasty presented with an enlarging pseudotumor. Pseudotumor is a known complication following metal-on-metal and metal-on-conventional polyethylene and metal-on-highly cross-linked polyethylene implants. Revision total hip arthroplasty following resection of pseudotumor has resulted in an increase in incidence of postoperative complications. Despite stable implants, these complications arise from the amount of soft tissue damage combined with the loss of tissue support around the resected hip. Our case is a clear example of a major complication, recurrent dislocation, following resection and revision surgery. PMID:25161791

Lee, Jason; Schwarzkopf, Ran

2014-01-01

145

Bullet in Hip Joint  

PubMed Central

Recently, hip arthroscopy has become more popular in the diagnosis and extraction of intraarticular foreign bodies compared to open surgery. If a foreign object such as a bullet is not extracted from the hip joint, it may cause mechanical arthritis, infection and systemic lead toxicity. We present the arthroscopic excision of a bullet from the hip joint of a 33-year-old male patient who sustained a gunshot injury.

Kaya, Ibrahim; Ugras, Akin; Saglam, Necdet; Sungur, Ibrahim; Cetinus, Ercan

2013-01-01

146

Hip fracture surgery  

MedlinePLUS

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

147

Short stems in total hip replacement: current status and future.  

PubMed

Short stem hip implants have been introduced as a bone preserving surgery for younger and more active people undergoing hip arthroplasty. Although many short stems are now available, clinical results and long-term survival are controversial. The aim of this paper is to describe the features of the short stems and to analyse their clinical results and long-term survival. The short-stem implants reproduce a stress distribution at the level of the proximal femur more similar to the physiological femur limiting the stress-shielding that occur with conventional cementless stems. Though short stems are an alternative to conventional stems, their use is not yet justified despite the promising short and mid-term survival results. Higher incidence of complications, such as periprosthetic fractures and malpositioning of the stem, and the lack of long-term results do not allow to predict what role in the future short stems in total hip replacement may have. PMID:24970038

Castelli, Claudio C; Rizzi, Luigi

2014-01-01

148

Failure analysis of alumina on alumina total hip arthroplasty with a layered acetabular component: minimum ten-year follow-up study.  

PubMed

This prospective study reports the outcome of total hip arthroplasty (THA) performed in a consecutive series of patients using an alumina ceramic on a ceramic-layered component (Alumina-Bearing-Surface system). The cohort consisted of 270 hips in 229 patients. The study evaluated the clinical and radiological results over a mean follow-up of 11.4 years. Revision THA was performed on 58 hips, including alumina alternative failure in 50 hips, loosening in 4 hips, recurrent dislocation in 2 hips, stem neck fracture in 1 hip and hematoma in 1 hip. The survival rate was 68% with revision for any reason as the end point. The risk factors of implant failure are the preoperative range of motion of the hip joint and postoperative dislocation. PMID:23684661

Kawano, Shunsuke; Sonohata, Motoki; Shimazaki, Takafumi; Kitajima, Masaru; Mawatari, Masaaki; Hotokebuchi, Takao

2013-12-01

149

Uncemented custom femoral components in hip arthroplasty  

PubMed Central

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

2010-01-01

150

Total hip arthroplasty revision in elderly patients.  

PubMed

In the last years, the number of total hip arthroplasty is increased both in young patients and elderly with a poor bone quality due to extension of surgical indications. According to this trend, also revision surgery showed a growth of its number, especially in elderly patients, because of implant loosening, failed osseointegration of prosthetic components, errors in biomechanical restoration and infections. The aim of this study is to analyze life quality improvement through evaluation of articular functionality and postoperative pain, and to examine osseointegration of implant components with periprosthetic bone. During total hip arthroplasty revision, the orthopedic surgeon often has to face complex cases, especially in elderly patients with a preexisting status of poor bone quality and sarcopenia. In these cases, a correct planning and a surgical procedure well-executed are able to ensure a good outcome that led to pain relief and functional recovery. Furthermore anti-osteoporotic therapy surely represents a useful resource both in primary total hip arthroplasty and in revisions, mainly for elderly patients with a poor bone quality. PMID:24046034

Gasbarra, Elena; Perrone, Fabio Luigi; Celi, Monica; Rao, Cecilia; Feola, Maurizio; Cuozzo, Nicola; Tarantino, Umberto

2013-10-01

151

Cochlear Implants  

MedlinePLUS

... FDA) website on cochlear implants. Cochlear implants are electronic hearing devices. Doctors implant cochlear implants into people ... State & Local Officials Consumers Health Professionals Science & Research Industry Scroll back to top

152

Hip Resurfacing Arthroplasty  

Microsoft Academic Search

In the last 10 years, resurfacing hip arthroplasty has become a popular option again for treating hip disorders in younger, active patients in some parts of the world. We report the Australian experience with this operation based on the Australian National Joint Replacement Registry and the literature available on the Australian experience in Resurfacing.

Martin L. Buergi; William L. Walter

2007-01-01

153

Superion Interspinous Process Spacer for Intermittent Neurogenic Claudication Secondary to Moderate Lumbar Spinal Stenosis: Two-Year Results From a Randomized Controlled FDA-IDE Pivotal Trial.  

PubMed

Study Design. Prospective, multicenter, randomized, controlled, investigational device exemption (IDE) noninferiority trial.Objective. To determine 2-year outcomes in patients with intermittent neurogenic claudication secondary to moderate lumbar spinal stenosis (LSS) who were treated with the Superion interspinous process spacer.Summary of Background Data. Interspinous spacers are a less invasive treatment alternative compared to surgical decompression for patients with LSS unresponsive to conservative care. High-quality comparative data with these devices are lacking.Methods. Patients presenting with intermittent neurogenic claudication secondary to moderate LSS who failed at least 6 months of nonsurgical management were randomly allocated to treatment with the Superion spacer or a control spacer (X-STOP) and followed for 2 years.Results. A total of 391 randomized patients were implanted with Superion (n = 190) or control (n = 201) spacers at 29 sites in the US between August 2008 and December 2011. Implants were successfully implanted in 99.5% of Superion patients and 99.0% of control patients. The primary composite endpoint of this study was met, which demonstrated that the Superion spacer was noninferior to the X-Stop spacer. Leg pain, the predominant patient complaint, decreased in severity by 70% over 2 years in each group. Most (77%) patients achieved leg pain clinical success (improvement ? 20 mm) at 2 years. Back pain clinical success (improvement ? 20 mm) was 68%, with no differences between groups. ODI clinical success (?15 percentage point improvement) was achieved in 65% of patients. The rates of complications and reoperations were similar between groups.Conclusions. The Superion interspinous process spacer relieves symptoms of intermittent neurogenic claudication secondary to moderate LSS in the majority of patients through 2 years. PMID:25494323

Patel, Vikas V; Whang, Peter G; Haley, Thomas R; Bradley, W Daniel; Nunley, Pierce D; Davis, Raphael P; Miller, Larry E; Block, Jon E; Geisler, Fred H

2014-12-01

154

More ribosomal spacer sequences from Xenopus laevis.  

PubMed Central

The base sequence analysis of a Xenopus laevis ribosomal DNA repeat (7) has been extended to cover almost the entire non-transcribed and external transcribed spacer. A compilation of these sequences is presented. All the repetitive and non-repetitive sequence elements of the spacer are identified and their evolution discussed. Comparison of the X.laevis and S.cerevisiae (25,26) ribosomal DNAs shows about 80% sequence conservation in the 18S gene but no sequence conservation, from the available data, in the external transcribed spacer. The sequence coding for the 3' terminus of the X.laevis 40S ribosomal precursor RNA is presented and its structural features analyzed. Images PMID:7003549

Moss, T; Boseley, P G; Birnstiel, M L

1980-01-01

155

Bipolar hip arthroplasty.  

PubMed

Our aim was to compare hip arthroplasty with internal screw fixation in the repair of intertrochanteric fractures in elderly patients with osteoporosis. Of 112 included patient, 70 (81.81 ± 4.88 years) received hip arthroplasty with a prosthesis specially designed for intertrochanteric fractures, and 42 (83.46 ± 5.11 years) underwent plate-screw fixation. The hip arthroplasty group had significantly longer operation time, intraoperative blood loss, and total volume of blood transfused but had shorter time to beginning weight-bearing (5.94 ± 2.76 vs 23.68 ± 22.01 days) and higher postoperative Harris hip score (91.37 ± 4.80 vs 86.14 ± 5.46). In the arthroplasty group, there were 2 dislocations; and in the plate-screw fixation group, there were 5 internal fixation failures. Hip arthroplasty is preferable to internal fixation in elderly patients (age >80 years) with osteoporosis. PMID:21530148

Chang, Qing; Liu, Shubing; Guan, Changyong; Yu, Fangyuan; Wu, Shenguang; Jiang, Changliang

2011-12-01

156

Revision and complication rates in 654 Exeter total hip replacements, with a maximum follow-up of 20 years  

Microsoft Academic Search

BACKGROUND: Iceland's geographical isolation with a stable and small population gives a rare opportunity for follow-up studies of medical interventions. Total hip replacements (THR) have been done at FSA Central Hospital in Akureyri, Iceland since 1982 with the Exeter hip implant being in use from the beginning. METHODS: Hospital records for all patients operated on with THR between 1982 and

Jonas Franklin; Otto Robertsson; Julius Gestsson; L Stefan Lohmander; Thorvaldur Ingvarsson

2003-01-01

157

Anterior hip capsuloligamentous reconstruction for recurrent instability after hip arthroscopy.  

PubMed

A variety of complications, including iatrogenic anterior hip instability, have been reported after hip arthroscopy. We present a case of a patient sustaining a postoperative anterior hip dislocation after cam resection for treatment of femoroacetabular impingement. Our patient developed persistent instability and required anterior capsuloligamentous reconstruction with iliotibial autograft. We present a comprehensive review of the literature on postoperative hip instability after hip arthroscopy, including the role of capsulotomy closure, and use of postoperative orthotics and weight-bearing restrictions. PMID:25490020

Dierckman, Brian D; Guanche, Carlos A

2014-12-01

158

Concerns with modularity in total hip arthroplasty.  

PubMed

Modularity is being diversified in total hip prostheses to increase surgical latitude in optimizing implant fixation and adjusting hip biomechanics. However, several problems have been clearly identified with implant modularity. First generation metal-backed acetabular components have shown deficiencies in the locking mechanism, the congruency and extent of polyethylene liner support, and polyethylene thickness, all of which have been implicated in accelerated polyethylene wear and failure. Evidence of screw motion against the metal backing, release of particulate material, and focal osteolysis have also been observed. At the head/neck junction evidence of corrosion and fretting has been documented with both similar-metal and mixed-metal taper combinations. Femoral prostheses with other sites of modularity present additional concerns with regard to mechanical integrity and generation of particulate debris by fretting. The modular junctions of three hip prostheses, the S-ROM, Infinity, and RMHS, were subjected to wet environment high cycle mechanical testing in a worst-case loading scenario. Preliminary results at relatively low loads up to three times body weight indicated gross stability of the modular junctions with evidence of minor fretting damage. Analysis of water solutions surrounding the modular junctions after ten to 20 million loading cycles yielded counts of one to three micron sized particles totalling several hundred thousand to several million. It is unknown what quantity of particulate material is sufficient to cause macrophage-mediated osteolysis or whether the debris from modular junctions can cause third-body wear of the articulating surfaces. Modular hip prostheses should be examined under stringent test conditions in order to characterize their fretting behavior and establish their mechanical limitations. PMID:8118986

Bobyn, J D; Tanzer, M; Krygier, J J; Dujovne, A R; Brooks, C E

1994-01-01

159

Separator-spacer for electrochemical systems  

DOEpatents

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.

Grimes, Patrick G. (Westfield, NJ); Einstein, Harry (Springfield, NJ); Newby, Kenneth R. (Berkeley Heights, NJ); Bellows, Richard J. (Westfield, NJ)

1983-08-02

160

Engineering biocompatible implant surfaces. Part I: Materials and surfaces  

Microsoft Academic Search

During recent decades vast and continuously increasing numbers of biomedical implants have been introduced for continuous use in the human body. Since the early cemented hip replacements in the 1960s there has been a constant spread of new materials, and ever more complex designs are being used in these implant devices. But still the rate of failure and loss of

S. a Bauer; P.a Schmuki; K. b von der Mark; J. c Park

2012-01-01

161

Design-Optimization and Material Selection for a Proximal Radius Fracture-Fixation Implant  

E-print Network

. For example, long-term fatigue-controlled stability of hip implants has been evaluated under the conditions of more complex physiological loading conditions in the experimental pre- clinical implant evaluation. To expand the set of physiological loading conditions experienced by the implant during normal everyday

Grujicic, Mica

162

ROUGH SURFACES OF TITANIUM AND TITANIUM ALLOYS FOR IMPLANTS AND PROSTHESES  

E-print Network

ROUGH SURFACES OF TITANIUM AND TITANIUM ALLOYS FOR IMPLANTS AND PROSTHESES 1 E. Conforto, 2 B. Abstract Titanium and titanium alloys for dental implants and hip prostheses were surface-treated and and the stability of the implant. The microstructure of titanium and titanium alloys submitted to these treatments

Boyer, Edmond

163

Nitriding of titanium disks and industrial dental implants using hollow cathode discharge  

Microsoft Academic Search

Standard plasma nitriding of commercially pure Ti or various Ti alloys for human body implants (e.g., hip, knee, shoulder and ankle implants) has already proven useful. However, its use in dental implantology is rather limited due to high nitriding temperatures. The small dental implants of complex geometries are frequently distorted. To solve this problem and benefit from the ability of

C ALVESJR; C. L. B. Guerra Neto; G. H. S. Morais; C. F. da Silva; V. Hajek

2005-01-01

164

Bursitis of the Hip  

MedlinePLUS

... few days to several weeks, and it can go away and come back again. Acute bursitis can become chronic if it come backs or if a hip injury occurs. Over time, the bursa may become thick, which can make ...

165

Ultrasound: Infant Hip  

MedlinePLUS

... hip area, and images are recorded on a computer. The black-and-white images show the internal ... the images can be seen clearly on the computer screen. A technician (sonographer) trained in ultrasound imaging ...

166

Hip Problems in Infants  

MedlinePLUS

... hip problems can be treated with a soft brace called a "Pavlik harness." This brace keeps your baby's knees spread apart and bent ... in place, your baby will keep wearing the brace for another 2 or 3 months. Your baby ...

167

Arthroscopic Hip Labral Repair  

PubMed Central

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

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

2013-01-01

168

Hip Conditioning Program  

MedlinePLUS

... of your abdomen to prevent you from leaning backward. Hip Conditioning Program Strengthening exerciSeS © American Academy of ... and do not lean your body forward or backward. © American Academy of Orthopaedic Surgeons Exercises Page 5 ...

169

Medical implants and methods of making medical implants  

DOEpatents

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.

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

2014-09-16

170

Implant infections: a haven for opportunistic bacteria  

Microsoft Academic Search

The insertion of implants and medical devices has emerged as a common and often life-saving procedure. A current estimate of the rate of total hip replacement in the world is approximately one million a year, and knee replacements more than 250000. More than 30% of hospitalized patients have one or more vascular catheters in place. More than 10% of hospitalized

J. M. Schierholz; J. Beuth

2001-01-01

171

Field study of offshore cement-spacer mixing  

SciTech Connect

Rheological data from cementing-spacer fluids are usually based on laboratory-prepared samples of the spacer and used to determine the flow rate required to provide the flow regime necessary for maximum efficiency of the spacer and to estimate the annular friction pressures associated with the spacer. Actual rheological properties are rarely measured on location, and the problems experienced with settling, foaming, and mixing are difficult to simulate in the laboratory. This paper reviews the field data from three commercial spacers mixed at offshore locations and compares them with laboratory data for base spacer materials and weighted spacer mixes. The flow rates required to obtain turbulent and plug flow for each spacer are compared, and settling, foaming, and mixing problems are discussed. Because of solids settling in either the slugging pits or surface samples, the spacer formula is sometimes modified on location to improve solids suspension. The rheological effects of increasing concentrations of base spacer material, bentonite, and polyanionic cellulose (PAC) are discussed with a comparison of the rheological data from these spacers.

Benge, G. (Mobil E and P Services Inc. (US))

1990-09-01

172

Heterogeneous diversity of spacers within CRISPR  

NASA Astrophysics Data System (ADS)

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

Deem, Michael; He, Jiankui

2011-03-01

173

Honeycomb spacer crush stength test results  

SciTech Connect

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.

Leader, D.R.

1993-09-15

174

Do Tantalum and Titanium Cups Show Similar Results in Revision Hip Arthroplasty?  

Microsoft Academic Search

Porous surfaces are intended to enhance osteointegration of cementless implants. Tantalum has been introduced in an effort\\u000a to enhance osseointegration potential of uncemented components. We therefore compared the clinical outcome of acetabular components\\u000a with two different porous surfaces. We retrospectively reviewed 283 patients (295 hips) who underwent cementless revision\\u000a hip arthroplasty with either an HA-coated titanium cup (207 patients, 214

S. Mehdi Jafari; Benjamin Bender; Catelyn Coyle; Javad Parvizi; Peter F. Sharkey; William J. Hozack

2010-01-01

175

LDL adsorbent with dendrimer PAMAM as spacer  

Microsoft Academic Search

Dendritic polymers are three-dimensional, highly ordered compounds formed by reiterative reaction sequences, and via discrete\\u000a stages referred to as generations. To study the spacer effect of low density lipoprotein (LDL) adsorbent, we linked dendrimer\\u000a polyamidoamine (PAMAM) generation 1 (G1), generation 3 (G3) and generation 5 (G5) to cellulose beads, respectively, and then\\u000a determined the adsorption proportion of the adsorbents with

Yi Yuan; Yanming Wang; Yaoting Yu

2008-01-01

176

Artificial hip joints: The biomaterials challenge.  

PubMed

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

Pezzotti, Giuseppe; Yamamoto, Kengo

2014-03-01

177

Investigations on a LISA Telescope Spacer  

NASA Astrophysics Data System (ADS)

The Laser Interferometer Space Antenna (LISA) is a space-based mission designed to observe gravitational waves from 0.1 mHz to 1 Hz. Using a triangular constellation of three spacecraft separated by 5x10^6 km, LISA will be able to detect the length changes between the spacecraft induced by gravitational waves. These length changes can be detected with pm/rtHz sensitivity using laser interferometry. Each spacecraft must contain two telescopes that can transmit and receive light between spacecraft. To expand and collimate the beam, a two-mirror system was designed with a primary and secondary mirror separated by a spacer. The noise requirements for LISA demand that the telescope spacer must be extremely stable. Two designs, on-axis and off-axis, are being considered for the telescope spacer. Various materials are also being examined. An on-axis silicon carbide telescope test structure was built to assess the stability of this configuration. A Michelson Interferometer was used to monitor length changes of the test structure while being cooled to space-like temperatures. Stability measurements are currently being made by locking the telescope laser to a cavity mounted on the test structure and then the beat note between the telescope laser and another cavity-locked laser is observed. A beat note between another laser locked to the Doppler-free spectral lines of iodine and the telescope laser will be used to determine the long term stability of the test structure.

Spector, Aaron; Sanjuan, Josep; Preston, Alix

2010-10-01

178

Pattern Alteration: Protruding Hip Bone  

E-print Network

People with very thin figures typically have to alter their clothing for protruding hip bones. This is because diagonal wrinkles radiate from the hip bones. This well-illustrated publication shows how to correct this problem in pants and skirts....

2006-08-04

179

Dual mobility cups in total hip arthroplasty.  

PubMed

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

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

2014-07-18

180

Extra-articular hip endoscopy  

PubMed Central

The aim of this review is to evaluate the current available literature evidencing on peri-articular hip endoscopy (the third compartment). A comprehensive approach has been set on reports dealing with endoscopic surgery for recalcitrant trochanteric bursitis, snapping hip (or coxa-saltans; external and internal), gluteus medius and minimus tears and endoscopy (or arthroscopy) after total hip arthroplasty. This information can be used to trigger further research, innovation and education in extra-articular hip endoscopy. PMID:23610664

Verhelst, L.; Guevara, V.; De Schepper, J.; Van Melkebeek, J.; Pattyn, C.; Audenaert, E. A.

2012-01-01

181

Pattern Alteration: Even Hip Circumference  

E-print Network

Even Hip Circumference Extension Family Development and Resource Management Specialists B Pattern Alteration E-386 05-06 efore attempting this alteration, review Extension publications E-372, Principles of Pattern Alteration, and E-373, Personal... Measurement Chart, for basic instruc- tions. Even Hip Circumference shows how to alter garments to fi t a fi gure with even hips. If only certain areas of the gar- ment are tight or loose, you may need different instructions. Review E-374, Back Hip Fullness...

2006-08-04

182

Revision total hip arthroplasty using the Zweymuller femoral stem  

PubMed Central

Background A variety of femoral stem designs have been reported to be successful in revision total hip arthroplasty without consensus as to optimal design. We evaluated the clinical and radiographic outcomes in a consecutive series of femoral revisions using a wedge-shape, tapered-stem design at medium and long-term follow-up. Materials and methods We performed a retrospective review of clinical and radiographic outcomes of twenty-eight consecutive femoral revisions arthroplasties, which were done using the Zweymuller femoral stem. Results The mean follow-up was 7.4 years (range 2–15 years). No stem re-revision was necessary. All stems were judged to be stable by radiographic criteria at the most recent follow-up. The final mean Harris hip score was 90. There was no difference in Harris hip scores, implant stability, or radiological appearance (distal cortical hypertrophy or proximal stress shielding) of the implants between medium-term (mean 5.7 years) and long-term (mean 12.4 years) follow-up. Conclusions We found the Zweymuller femoral stem design to be durable for revision hip arthroplasty when there is an intact metaphyseal-diaphyseal junction for adequate press-fit stability at surgery. PMID:19384617

Huo, Michael H.; Keggi, Kristaps J.

2008-01-01

183

Impingement in Total Hip Replacement: Mechanisms and Consequences  

PubMed Central

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

Brown, Thomas D.; Callaghan, John J.

2009-01-01

184

Hip fractures in children.  

PubMed

Hip fractures account for <1% of all pediatric fractures. Most are caused by high-energy mechanisms, but pathologic hip fractures also occur, usually from low-energy trauma. Complications occur at a high rate because the vascular and osseous anatomy of the child's proximal femur is vulnerable to injury. Surgical options vary based on the child's age, Delbet classification type, and degree of displacement. Anatomic reduction and surgical stabilization are indicated for most displaced hip fractures. Other options include smooth-wire or screw fixation, often supplemented by spica cast immobilization in younger children, or compression screw and side plate fixation. Achievement of fracture stability is more important than preservation of the proximal femoral physis. Capsular decompression after reduction and fixation may diminish the risk of osteonecrosis. Osteonecrosis, coxa vara, premature physeal closure of the proximal femur, and nonunion are complications that account for poor outcomes. PMID:19264709

Boardman, Matthew J; Herman, Martin J; Buck, Brian; Pizzutillo, Peter D

2009-03-01

185

No Difference in Gender-specific Hip Replacement Outcomes  

Microsoft Academic Search

Gender-specific total hip arthroplasty (THA) design has been recently debated with manufacturers launching gender-based designs.\\u000a The purpose of this study was to investigate the survivorship and clinical outcomes of a large primary THA cohort specifically\\u000a assessing differences between genders in clinical outcomes, implant survivorship, revisions as well as sizing and offset differences.\\u000a We reviewed 3461 consecutive patients receiving 4114 primary

Timothy Kostamo; Robert B. Bourne; John Paul Whittaker; Richard W. McCalden; Steven J. MacDonald

2009-01-01

186

Initial increased wear debris of XLPE-Al 2 O 3 bearing in total hip arthroplasties  

Microsoft Academic Search

Introduction  Aseptic implant loosening caused by wear debris is a common reason for early implant failure after total hip replacement (THR).\\u000a \\u000a \\u000a \\u000a Materials and methods  We prospectively studied 96 patients (110 hips), 48 men and 48 women (mean age 46.8 years, mean body mass index 26.1) who\\u000a had undergone cementless THR (titanium stem, press-fit cup, Al2O3 ball, XLPE liner) at a mean of 17.4 months

Marcus Jäger; Michael Behringer; Christoph Zilkens; Travis Matheney; Rüdiger Krauspe

2010-01-01

187

Revision in cemented and cementless infected hip arthroplasty.  

PubMed

Infection is a frequent cause of failure after joint replacement surgery. The infection rate after total hip arthroplasty (THA) has been reduced to 1-2% in the last years. However, it still represents a challenging problem for the orthopedic surgeon. Difficulty of therapeutic approach, and poor functional outcomes together with length of treatment and overall cost are the main burden of this issue. Even the diagnosis of an infected hip could be challenging although it is the first step of an accurate treatment. At the end, many cases require removing the implants. Afterwards, the treatment strategy varies according to authors with three different procedures: no re-implantation, immediate placement of new implants or a two-stage surgery re-implantation. Based on the most recently systematic review there is no suggestion that one- or two-stage revision methods have different re-infection outcomes. The two-stage implant-exchange protocol remains the gold standard. It is considered as the most efficacious clinical approach for the treatment of periprosthetic infection, especially in patients with sinus tracts, swelling, extended abscess formation in depth and infection of Methicillin Resistant Staphylococcus Aureus (MRSA), and other multidrug-resistant bacteria as reported in recent consensus documents. PMID:23898351

Cherubino, Paolo; Puricelli, Marco; D'Angelo, Fabio

2013-01-01

188

Revision in Cemented and Cementless Infected Hip Arthroplasty  

PubMed Central

Infection is a frequent cause of failure after joint replacement surgery. The infection rate after total hip arthroplasty (THA) has been reduced to 1-2% in the last years. However, it still represents a challenging problem for the orthopedic surgeon. Difficulty of therapeutic approach, and poor functional outcomes together with length of treatment and overall cost are the main burden of this issue. Even the diagnosis of an infected hip could be challenging although it is the first step of an accurate treatment. At the end, many cases require removing the implants. Afterwards, the treatment strategy varies according to authors with three different procedures: no re-implantation, immediate placement of new implants or a two-stage surgery re-implantation. Based on the most recently systematic review there is no suggestion that one- or two-stage revision methods have different re-infection outcomes. The two-stage implant-exchange protocol remains the gold standard. It is considered as the most efficacious clinical approach for the treatment of periprosthetic infection, especially in patients with sinus tracts, swelling, extended abscess formation in depth and infection of Methicillin Resistant Staphylococcus Aureus (MRSA), and other multidrug-resistant bacteria as reported in recent consensus documents. PMID:23898351

Cherubino, Paolo; Puricelli, Marco; D’Angelo, Fabio

2013-01-01

189

Numerical simulation of the insertion process of an uncemented hip prosthesis in order to evaluate the influence of residual stress and contact distribution on the stem initial stability  

Microsoft Academic Search

The long-term success of a cementless total hip arthroplasty depends on the implant geometry and interface bonding characteristics (fit, coating and ingrowth) and on stem stiffness. This study evaluates the influence of stem geometry and fitting conditions on the evolution and distribution of the bone–stem contact, stress and strain during and after the hip stem insertion, by means of dynamic

Aida Georgeta Monea; Leonard Cezar Pastrav; Michiel Mulier; Georges Van der Perre; Siegfried V. Jaecques

2012-01-01

190

A modular distal fixation option for proximal bone loss in revision total hip arthroplasty: A 2- to 6-year follow-up study  

Microsoft Academic Search

Proximal femoral bone deficiency in the failed total hip arthroplasty (THA) is addressed with difficulty using proximally fixed implants. The Link MP reconstruction hip stem is proximally modular but utilizes distal fixation. This series consists of 143 patients from 3 clinical sites. Of the patients, 81 were women. The average follow-up time was 40 months, and the average patient age

Louis M. Kwong; A. John Miller; Phillipp Lubinus

2003-01-01

191

Clinical Outcomes Assessment of Three Similar Hip Arthroplasty Bearing Surfaces  

PubMed Central

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

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

2014-01-01

192

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

PubMed Central

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

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

2014-01-01

193

Pain after hip arthroplasty managed by Brennan Healing Science.  

PubMed

A case is presented illustrating the potential effect of Brennan Healing Science on pain following hip arthroplasty for avascular necrosis. A 54-year-old woman experienced anterior groin pain, numbness at the bottom of her foot, and occasional grinding at her hip 22 years after right total hip arthroplasty secondary to avascular necrosis. X-ray films showed signs of osteolysis behind the acetabular cup and asymmetric decreased polyethylene thickness of the acetabular prosthetic. Her orthopedic surgeon advised the patient to follow up every 6-9 months to avoid catastrophic failure of the implant, with plans for surgical revision to be scheduled at the next appointment. The patient sought alternative treatment to avoid an invasive procedure. On presentation, the patient had difficulty walking up the stairs into the treatment room due to pain which she rated a 9/10. She found it painful to rotate, flex, extend her hip, or to sit. Hands-on healing techniques based on the Brennan Healing Science method were initiated, starting at the feet, balancing the energy, and working the way up the joints. Once the work at the hip was completed, the hands-on techniques continued up the centerline of the body and the healing was brought to a close. On completion of a 60-minute healing, the patient was able to stand freely and rated her pain as a 4/10. Flexion, extension, and rotation at the hip were no longer distressing. She was able to walk up and down stairs without distress and denied instability, bursitis, or trochanteric or iliopsoas pain or swelling. Repeat X-rays showed decrease in bone spurs and no hardware problem, and her orthopedic surgeon recommended follow-up after 2 years. It is suggested that Brennan Healing Science techniques could play an effective and cost-efficient role in the treatment of pain following hip arthroplasty. PMID:24439097

Namavar, Roxanna

2014-01-01

194

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

Code of Federal Regulations, 2010 CFR

...femoral (hemi-hip) metallic resurfacing prosthesis. 888.3400 Section 888.3400...femoral (hemi-hip) metallic resurfacing prosthesis. (a) Identification. A hip...femoral (hemi-hip) metallic resurfacing prosthesis is a device intended to be...

2010-04-01

195

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

Code of Federal Regulations, 2011 CFR

...femoral (hemi-hip) metallic resurfacing prosthesis. 888.3400 Section 888.3400...femoral (hemi-hip) metallic resurfacing prosthesis. (a) Identification. A hip...femoral (hemi-hip) metallic resurfacing prosthesis is a device intended to be...

2011-04-01

196

Heat-transfer augmentation in rod bundles near grid spacers  

Microsoft Academic Search

Heat-transfer augmentation by straight grid spacers in rod bundles is studied for single-phase flow and for post-critical heat flux dispersed flow. The heat transfer effect of swirling grid spacers in single-phase flow is also examined. Governing heat-transfer mechanisms are analyzed, and predictive formulations are established. For single-phase flow, the local heat transfer at a straight spacer and at its upstream

S. C. Yao; L. E. Hochreiter; W. J. Leech

1982-01-01

197

Hip Resurfacing Data from National Joint Registries: What Do They Tell Us? What Do They Not Tell Us?  

Microsoft Academic Search

Current-generation metal-on-metal hip resurfacing implants (SRAs) have been in widespread global use since the 1990s, and\\u000a in the United States, specific implants have recently been approved for clinical use. Many recent publications describe short-term\\u000a survivorship achieved by either implant-designing surgeons or high-volume centers. National joint replacement registries (NJRRs)\\u000a on the other hand report survivorship achieved from the orthopaedic community at

Kristoff Corten; Steven J. MacDonald

2010-01-01

198

Hip joint replacement  

MedlinePLUS

... Jones CA. Total joint arthroplasties: current concepts of patient outcomes after surgery. Rheum Dis Clin North Am . 2007;33(1):71-86. Schmalzried TP. Metal-metal bearing surfaces in hip arthroplasty. Orthopedics . 2009;32. Lindstrom D, Sadr Azodi O, Wladis ...

199

INL HIP Plate Fabrication  

SciTech Connect

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.

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

2010-02-01

200

Is reverse hybrid hip replacement the solution?  

PubMed Central

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

2011-01-01

201

Wear of metal-on-metal hip bearings: metallurgical considerations after hip simulator studies.  

PubMed

Metal-on-metal hip-bearing components with different percentages of carbon content (low and high carbon) were tested in 6 different configurations using a hip joint simulator. The aim of this study was to characterize metallurgical and tribological events occurring at the articulating surfaces of these articulations. Also, ion release was evaluated and correlated with wear. After the test, for the high-carbon components, carbides were observed below the matrix surface. In the low-carbon content components, most carbides were "carbide-free", while a minority were worn below the matrix surface with increased test cycles. In the cast alloy components, some carbides were pulled out resulting in micropits. Scanning microscope electron characterization of the tested specimens showed scratches and holes. The surface showed a dominant severe wear mechanism due to third-body particles. A greater amount of ions was released in the lubricant used during the wear test for the smaller diameter compared with the bigger one. This study showed that the metallurgical and tribological events taking place at the articulating surfaces of metal-metal hip implants are numerous and complex. The surface morphology after the test showed the effect of more critical working conditions with smaller diameters. PMID:22198601

Affatato, Saverio; Traina, Francesco; Ruggeri, Oddone; Toni, Aldo

2011-12-01

202

Evidence of MRSE on a gentamicin and vancomycin impregnated polymethyl-methacrylate (PMMA) bone cement spacer after two-stage exchange arthroplasty due to periprosthetic joint infection of the knee  

PubMed Central

Background Periprosthetic joint infections (PJI) are often treated by two stage exchange with the use of an antibiotic impregnated spacer. Most of the two-stage exchange algorithms recommend the implantation of an antibiotic-impregnated spacer during the first stage for a period of 2–24 weeks before reimplantation of the new prosthesis. For the spacer to have a therapeutic effect, the local antibiotic concentration must be greater than the minimal inhibition concentration (MIC) against the pathogens causing the PJI. It must remain so for the entire spacer period, otherwise recurrence of infection or resistances might occur. The question as to whether a sufficient concentration of antibiotics in vivo is reached for the entire spacer period has not been answered satisfactorily. Case presentation We here present a case of a histologically confirmed chronic PJI 20 month after primary arthroplasty. The primary knee arthroplasty was performed due to osteoarthritis of the joint. Initial assessment did not detect a causative pathogen, and two stage exchange with a vancomycin-gentamycin impregnated spacer was performed. At the time of reimplantation, sonication of the explanted spacer revealed a multi-resistant strain of staphylococcus epidermidis on the device and in the joint. Adaption of the therapy and prolonged treatment successfully eradicated the infection. Conclusion According to the authors’ knowledge, the case presented here confirms for the first time the surface contamination (proven through sonication) of a vancomycin-/gentamicin- impregnated Vancogenx®-spacer with a MRSE after ten weeks of implantation. This case study demonstrates the difficulties still associated with the diagnostics of PJI and the published different two stage treatment regimes with the use of antibiotic impregnated spacers. PMID:24641471

2014-01-01

203

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

PubMed Central

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

2011-01-01

204

Use of positron emission tomography to detect infection around antibiotic-loaded cement spacers in patients with high C-reactive protein levels.  

PubMed

In patients who have antibiotic-loaded cement hip spacers in the interim period, the correct diagnosis of infection eradication is the major determinant before reimplantation arthroplasty. Diagnosis is usually based on clinical findings and serum C-reactive protein (CRP) levels. However, diagnosis can be challenging when the clinical findings are normal but the CRP level is high. From March 2007 to January 2008, fluorodeoxy-glucose positron emission tomography (FDG-PET) was used to detect infection around antibiotic-loaded cement spacers in 13 patients (mean age, 60 years). Although patients' clinical conditions were deemed suitable for reimplantation, their serum CRP levels were persistently elevated (mean, 54 mg/L) an average of 120 days (range, 28-413 days) after the first-stage operation. Reimplantation total hip arthroplasty (THA) was subsequently performed in 7 patients based on the negative findings of FDG-PET. In 6 patients, FDG-PET was positive for infection. The persistence of infection was confirmed in 3 of these patients by another debridement surgery. Staged reimplantation THA was delayed in 1 patient who underwent repeat debridement and in 3 patients who were treated with extended periods of oral antibiotics. Of the 11 staged reimplantation THAs, only 1 reinfection was noted at an average follow-up of 48 months. The success rate of 91% suggests FDG-PET could help in the differential diagnosis of infection around cement spacers, especially in patients with normal clinical findings but elevated CRP levels. PMID:21956053

Huang, Ming-Jhe; Hsieh, Pang-Hsin; Ueng, Steve W N; Ho, Kung-Chu; Yen, Tzu-Chen; Lee, Mel S

2011-10-01

205

Survival analysis at 10 years of a cohort of 297 atlas total hip prostheses  

Microsoft Academic Search

The purpose of this work is to study the survival curve of Atlas hip prostheses (acetabular insert) implanted by a single\\u000a surgeon and with a minimum follow-up period of 10 years. Between January 1989 and December 1995, 297 ATLAS cups have been\\u000a implanted at the Clinic Saint André in Reims, 171 ATLAS II non coated with hydroxyapatite and 126 ATLAS III

Michel Philippe; Marc Ameil

2007-01-01

206

Cochlear Implants  

MedlinePLUS

... are better able to hear, comprehend sound and music, and speak than their peers who receive implants ... future hold for cochlear implants? With advancements in technology and continued follow-up studies with people who ...

207

Belt Machining and Testing of Ceramic Knee Implants  

Microsoft Academic Search

\\u000a Currently about five million people are diseased by arthrosis. This painful inflammation is often attended by an artificial\\u000a joint replacement.\\u000a \\u000a \\u000a Due to immune reactions resulting from the agglomeration of the polyethylene wear implant loosening appears. In the field\\u000a of hip endoprostheses the functionality of ceramic hip implants is well known since many years. To minimize the necessary\\u000a revision surgeries bioceramics

B. Denkena; L. Leon; A. Turger; B. Richter; C. Hurschler

208

Subtrochanteric Fracture following Removal of a Porous Tantalum Implant  

PubMed Central

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

Amanatullah, Derek F.; McDonald, Thomas J.; Moehring, H. David; Di Cesare, Paul E.

2013-01-01

209

Dislocation after total hip arthroplasty  

Microsoft Academic Search

Hip dislocation has long been one of the major complications after total hip arthroplasty (THA). From 1980 to 1994, we performed\\u000a 2728 THAs (including primary and revision cases). There were 97 hips (3.6%) with the complication of dislocation, 62 of which\\u000a were followed up for at least 2 years (mean 5.3 years; range 2–12 years). Single dislocations occurred in 40%

L.-J. Yuan; C.-H. Shih

1999-01-01

210

Sports After Hip Resurfacing Arthroplasty  

Microsoft Academic Search

Background: No information is available concerning patients' sports activity after hip resurfacing arthroplasty.Hypothesis: Patients treated by hip resurfacing arthroplasty will be able to achieve a high level of sports activity.Study Design: Case series; Level of evidence, 4.Methods: We surveyed 112 patients by postal questionnaire to determine their sporting activities at a mean of 23.5 (range, 9—40) months after hip resurfacing

Florian-D. Naal; Nicola A. Maffiuletti; Urs Munzinger; Otmar Hersche

2007-01-01

211

Osteopetrosis and total hip arthroplasty  

Microsoft Academic Search

Summary. Two patients with osteopetrosis and osteoarthrosis of the hip underwent “hybrid” total hip replacement. There are technical\\u000a difficulties in seating acetabular and femoral components on hard and brittle osteopetrotic bone with an obliterated marrow\\u000a cavity. Although the surgical procedures are challenging, this form of arthroplasty is recommended for hip osteoarthrosis\\u000a which is associated with osteopetrosis.\\u000a   

T. Matsuno; N. Katayama

1998-01-01

212

Hip muscle co-contraction: evidence from concurrent in vivo pressure measurement and force estimation  

Microsoft Academic Search

The biomechanical literature over the past three decades reports direct measurements of human hip joint contact forces from instrumented implants which in general are quite different than estimates of contact forces based on external kinematic-ground reaction force data and inverse Newtonian analyses. Because direct physical measurement establishes veridical values in science, the higher analytical estimates may overestimate the balanced muscle

David E Krebs; Robert W Mann

1999-01-01

213

Graphitic Tribological Layers in Metal-on-Metal Hip Replacements  

NASA Astrophysics Data System (ADS)

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.

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

2011-12-01

214

Clinical performance of a highly cross-linked polyethylene at two years in total hip arthroplasty: a randomized prospective trial  

Microsoft Academic Search

We report the 2-year results for a prospective randomized trial comparing highly cross-linked with standard polyethylene in total hip replacements. In our study, 46 hips were available for radiographic analysis at 2- and 3-year follow-up. Femoral bearings were 28-mm cobalt chrome with the polyethylene insert randomly selected at the time of implantation to be highly cross-linked polyethylene (Crossfire; Stryker Howmedica

John M Martell; James J Verner; Stephen J Incavo

2003-01-01

215

Cup position alone does not predict risk of dislocation after hip arthroplasty.  

PubMed

We used a large prospective institutional registry to determine if there is a 'safe zone' that 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 arthroplasty 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 radiographic zones (±5°,±10°,±15° boundaries). Dislocators <50years old were less active preoperatively than nondislocators (P=0.006). Acetabular component position alone is not protective against instability. PMID:25249516

Esposito, Christina I; Gladnick, Brian P; Lee, Yuo-Yu; Lyman, Stephen; Wright, Timothy M; Mayman, David J; Padgett, Douglas E

2015-01-01

216

Joint-preserving surgical options for management of chondral injuries of the hip.  

PubMed

Management of injuries to the articular cartilage is complex and challenging; it becomes especially problematic in weight-bearing joints such as the hip. Several causes of articular cartilage damage have been described, including trauma, labral tears, and femoroacetabular impingement, among others. Because articular cartilage has little capacity for healing, nonsurgical management options are limited. Surgical options include total hip arthroplasty, microfracture, articular cartilage repair, autologous chondrocyte implantation, mosaicplasty, and osteochondral allograft transplantation. Advances in hip arthroscopy have broadened the spectrum of tools available for diagnosis and management of chondral damage. However, the literature is still not sufficiently robust to draw firm conclusions regarding best practices for chondral defects. Additional research is needed to expand our knowledge of and develop guidelines for management of chondral injuries of the hip. PMID:24382879

El Bitar, Youssef F; Lindner, Dror; Jackson, Timothy J; Domb, Benjamin G

2014-01-01

217

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

PubMed Central

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

2013-01-01

218

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

PubMed

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

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

2014-12-01

219

Have the media influenced the use of hip resurfacing arthroplasty? A review of UK print media  

PubMed Central

INTRODUCTION The aim of this study was to look at the different claims made about hip resurfacing arthroplasty in the popular UK print media and how this relates to findings in the scientific literature. METHODS A review of UK popular print media from January 1992 to June 2011 was performed using the Lexis® Library online news database. Only articles discussing the clinical results of hip resurfacing arthroplasty were included. After excluding duplicates, 49 newspaper articles were found suitable for this study. The main outcome measure was the claims made in popular UK print media about hip resurfacing. These were compared with the scientific publication. We reviewed the trend of use of hip resurfacing prostheses during the same period as reported in the National Joint Registry. RESULTS A disparity was found between the claims in the newspapers and published scientific literature. The initial newspaper articles highlighted only the positive aspects of hip resurfacing arthroplasty, without definitive contemporary evidence backing the claims. Most of these claims were refuted by future scientific publications. The initial positive media reports coincided with an increase in the use of hip resurfacing but the decline coincided with negative reports in the scientific literature. CONCLUSIONS The trend of the newspaper articles and that of the number of hip resurfacing prostheses implanted suggests that the media may have been partly responsible for the increased use of this prosthesis. The subsequent decrease was initiated by the scientific literature. PMID:22943335

Malviya, A; Stafford, GH; Villar, RJF; Villar, RN

2012-01-01

220

Rough surfaces of titanium and titanium alloys for implants and prostheses  

Microsoft Academic Search

Titanium and titanium alloys for dental implants and hip prostheses were surface-treated and\\/or covered by metallic or ceramic rough layers after being submitted to sand blasting. The goal of these treatments is to improve the surface roughness and consequently the osteointegration, the fixation, and the stability of the implant. The microstructure of titanium and titanium alloys submitted to these treatments

E. Conforto; B.-O. Aronsson; A. Salito; C. Crestou; D. Caillard

2004-01-01

221

Results of the cementless Plasmacup in revision total hip arthroplasty: a retrospective study of 72 cases with an average follow-up of eight years  

Microsoft Academic Search

BACKGROUND: There are multiple revision implant systems currently available for socket revision in revision total hip arthroplasty. Up until now, not all of these systems have been followed up with regards to their long-term use as a revision implantation. For the first time, this study presents the hemispherical porous-coated socket Plasmacup SC, produced by Aesculap, Tuttlingen, Germany, and the clinical

Stefan Lakemeier; Guenter Aurand; Nina Timmesfeld; Thomas J Heyse; Susanne Fuchs-Winkelmann; Markus D Schofer

2010-01-01

222

CoCrMo Metal-on-Metal Hip Replacements  

PubMed Central

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

Liao, Yifeng; Hoffman, Emily; Wimmer, Markus; Fischer, Alfons; Jacobs, Joshua; Marks, Laurence

2012-01-01

223

Pervasive generation of oppositely oriented spacers during CRISPR adaptation  

PubMed Central

During the process of prokaryotic CRISPR adaptation, a copy of a segment of foreign deoxyribonucleic acid referred to as protospacer is added to the CRISPR cassette and becomes a spacer. When a protospacer contains a neighboring target interference motif, the specific small CRISPR ribonucleic acid (crRNA) transcribed from expanded CRISPR cassette can protect a prokaryotic cell from virus infection or plasmid transformation and conjugation. We show that in Escherichia coli, a vast majority of plasmid protospacers generate spacers integrated in CRISPR cassette in two opposing orientations, leading to frequent appearance of complementary spacer pairs in a population of cells that underwent CRISPR adaptation. When a protospacer contains a spacer acquisition motif AAG, spacer orientation that generates functional protective crRNA is strongly preferred. All other protospacers give rise to spacers oriented in both ways at comparable frequencies. This phenomenon increases the repertoire of available spacers and should make it more likely that a protective crRNA is formed as a result of CRISPR adaptation. PMID:24728991

Shmakov, Sergey; Savitskaya, Ekaterina; Semenova, Ekaterina; Logacheva, Maria D.; Datsenko, Kirill A.; Severinov, Konstantin

2014-01-01

224

Hip-Hop Education Resources  

ERIC Educational Resources Information Center

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.…

Hall, Marcella Runell

2009-01-01

225

Strontium in the bone-implant interface.  

PubMed

Total hip replacement surgery is being performed on an increasingly large part of the population and at increasingly younger age. Because we live and stay physically active longer, and since hip replacement surgery has become quite successful, the treatment is being offered to progressively more patients. Unfortunately, about 17% of hip replacement surgeries currently involve revisions. Consequently, the longevity of both the primary and revision implant is an issue and warrants further investigation. Implants undergoing early instability or even subsidence correlate with an increased risk of aseptic loosening, subsequently requiring revision. Thus, the goal is early fixation by osseointegration of the implant. For revision implants, this is an even greater challenge since an allograft is often needed during surgery to obtain immediate stability of the implant. Bone grafts are rapidly resorbed. Thus, instability of the prosthesis may develop before new bone formation is well established and can mechanically secure the prosthesis. Strontium is a dual action drug; being both bone anabolic and anti-catabolic. In the form of strontiumranelate, it is used in the treatment of osteoporosis. Strontium may potentially improve the early osseointegration and fixation of implants. This dissertation consists of three studies investigating the effect of strontium at the bone-implant interface. The questions were firstly, what is the optimal delivery method for strontium to the interface, and secondly, can strontium exercise its dual action at the interface? The studies were performed in a cementless, experimental gap model in canine. The effects of strontium were evaluated by histomorphometrical analysis of the osseointegration and mechanical push-out test of implant fixation. Different stereological methods were used for the histomorphometrical analysis of each study. The methods used were reviewed critically and found valid. Study I compared a 5% strontium-substituted hydroxyapatite (HA) coating with an HA coating after 4 weeks and 12 weeks observation time. We examined whether fixation of the implant was improved by the strontium substitution. It was found that fixation of the implant was not improved by the strontium substituted HA coating at any of the two time points. Study II compared a 5% strontium-doped HA bone graft extender with an HA bone graft extender. The bone graft extender was mixed with allograft and impacted around a titanium implant. The objective of this study was to determine whether strontium doping of the bone graft extender could protect the allograft from fast resorption and increase gap healing, leading to the improved fixation of the implant. We found that the strontium doping increased gap healing and protected the allograft, however, results of the mechanical test were inconclusive. The reason might have been that the increased gap healing had not yet reached the implant during the 4 weeks observation time, so ongrowth onto the implant was not improved. Study III investigated the effects of bioactive glass coating with a 0%, 10% or 50% strontium-substitution versus HA coating of grit-blasted titanium alloy implants. The goal was to determine whether fixation of the implant would be improved by the bioactive glass coating, and then further improved by the strontium-substitution of the coating in a dose-dependent manner. Unfortunately, the bioactive glass coating failed, presumably due to aluminum contamination originating from the grit-blasting powder. The HA coated implants were superior in all parameters of osseointegration and the mechanical fixation of the implants. These studies show the importance of performing further experimental investigation. Even when investigating a known agent for use in a new application. Strontium delivered as doping of an HA bone graft extender showed potential as a dual acting agent in the interface. However, delivery methods of strontium to the bone-implant interface clearly need further investigation. PMID:21535993

Vestermark, Marianne Toft

2011-05-01

226

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

PubMed

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

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

2014-01-01

227

Electrochemical instrumentation of a hip simulator: a new tool for assessing the role of corrosion in metal-on-metal hip joints.  

PubMed

Polyethylene wear debris induced osteolysis has triggered investigations to find alternative material combinations to the well-established metal-on-polyethylene hip implants. Owing to some early successful clinical cases, metal-on-metal (MoM) hip replacements have been attracting more and more interest. There is, however, considerable concern about the propensity of MoM hip replacements to release metal ions and fine, nanometre-scale metallic wear debris. The long-term effect from released metal ions and wear particles is still not clear. To date, all the work on hip simulators focused on assessing mass losses damage has been referred to as 'wear'. However, it is known in the field of tribocorrosion that mechanical removal of the passive layer on Co-Cr alloys can significantly enhance corrosion activity. In total joint replacements, it is possible that corrosion plays a significant role. However, no one has ever tried to extract, on a hip simulator, what proportion of the damage is due to mechanical processes and the corrosion processes. This paper describes the first instrumentation of an integrated hip joint simulator to provide in-situ electrochemical measurements in real time. The open circuit potential results are reported to assess the corrosion regime in the absence and presence of movement at the bearing surfaces. The importance of these measurements is that the real damage mechanisms can be assessed as a function of the operating cycle. PMID:21218689

Yan, Y; Neville, A; Dowson, D; Williams, S; Fisher, J

2010-11-01

228

Cobalt-alloy implant debris induce HIF-1? hypoxia associated responses: a mechanism for metal-specific orthopedic implant failure.  

PubMed

The historical success of orthopedic implants has been recently tempered by unexpected pathologies and early failures of some types of Cobalt-Chromium-Molybdenum alloy containing artificial hip implants. Hypoxia-associated responses to Cobalt-alloy metal debris were suspected as mediating this untoward reactivity at least in part. Hypoxia Inducible Factor-1? is a major transcription factor involved in hypoxia, and is a potent coping mechanism for cells to rapidly respond to changing metabolic demands. We measured signature hypoxia associated responses (i.e. HIF-1?, VEGF and TNF-?) to Cobalt-alloy implant debris both in vitro (using a human THP-1 macrophage cell line and primary human monocytes/macrophages) and in vivo. HIF-1? in peri-implant tissues of failed metal-on-metal implants were compared to similar tissues from people with metal-on-polymer hip arthroplasties, immunohistochemically. Increasing concentrations of cobalt ions significantly up-regulated HIF-1? with a maximal response at 0.3 mM. Cobalt-alloy particles (1 um-diameter, 10 particles/cell) induced significantly elevated HIF-1?, VEGF, TNF-? and ROS expression in human primary macrophages whereas Titanium-alloy particles did not. Elevated expression of HIF-1? was found in peri-implant tissues and synovial fluid of people with failing Metal-on-Metal hips (n?=?5) compared to failed Metal-on-Polymer articulating hip arthroplasties (n?=?10). This evidence suggests that Cobalt-alloy, more than other metal implant debris (e.g. Titanium alloy), can elicit hypoxia-like responses that if unchecked can lead to unusual peri-implant pathologies, such as lymphocyte infiltration, necrosis and excessive fibrous tissue growths. PMID:23840602

Samelko, Lauryn; Caicedo, Marco S; Lim, Seung-Jae; Della-Valle, Craig; Jacobs, Joshua; Hallab, Nadim J

2013-01-01

229

Cobalt-Alloy Implant Debris Induce HIF-1? Hypoxia Associated Responses: A Mechanism for Metal-Specific Orthopedic Implant Failure  

PubMed Central

The historical success of orthopedic implants has been recently tempered by unexpected pathologies and early failures of some types of Cobalt-Chromium-Molybdenum alloy containing artificial hip implants. Hypoxia-associated responses to Cobalt-alloy metal debris were suspected as mediating this untoward reactivity at least in part. Hypoxia Inducible Factor-1? is a major transcription factor involved in hypoxia, and is a potent coping mechanism for cells to rapidly respond to changing metabolic demands. We measured signature hypoxia associated responses (i.e. HIF-1?, VEGF and TNF-?) to Cobalt-alloy implant debris both in vitro (using a human THP-1 macrophage cell line and primary human monocytes/macrophages) and in vivo. HIF-1? in peri-implant tissues of failed metal-on-metal implants were compared to similar tissues from people with metal-on-polymer hip arthroplasties, immunohistochemically. Increasing concentrations of cobalt ions significantly up-regulated HIF-1? with a maximal response at 0.3 mM. Cobalt-alloy particles (1 um-diameter, 10 particles/cell) induced significantly elevated HIF-1?, VEGF, TNF-? and ROS expression in human primary macrophages whereas Titanium-alloy particles did not. Elevated expression of HIF-1? was found in peri-implant tissues and synovial fluid of people with failing Metal-on-Metal hips (n?=?5) compared to failed Metal-on-Polymer articulating hip arthroplasties (n?=?10). This evidence suggests that Cobalt-alloy, more than other metal implant debris (e.g. Titanium alloy), can elicit hypoxia-like responses that if unchecked can lead to unusual peri-implant pathologies, such as lymphocyte infiltration, necrosis and excessive fibrous tissue growths. PMID:23840602

Samelko, Lauryn; Caicedo, Marco S.; Lim, Seung-Jae; Della-Valle, Craig; Jacobs, Joshua; Hallab, Nadim J.

2013-01-01

230

Metal release and corrosion effects of modular neck total hip arthroplasty.  

PubMed

Modular neck implants are an attractive treatment tool in total hip replacement. Concerns remain about the mechanical stability and metal ion release caused by the modular connection. Five different implant designs were investigated in an experimental set-up. In vivo conditions were simulated and the long-term titanium release was measured. Finally, the modular connections were inspected for corrosion processes and signs of fretting. No mechanical failure or excessive corrosion could be identified for the implants tested. The titanium releases measured were extremely low compared to in vivo and in vitro studies and were not in a critical range. PMID:19219434

Kretzer, J Philippe; Jakubowitz, Eike; Krachler, Michael; Thomsen, Marc; Heisel, Christian

2009-12-01

231

Metal release and corrosion effects of modular neck total hip arthroplasty  

PubMed Central

Modular neck implants are an attractive treatment tool in total hip replacement. Concerns remain about the mechanical stability and metal ion release caused by the modular connection. Five different implant designs were investigated in an experimental set-up. In vivo conditions were simulated and the long-term titanium release was measured. Finally, the modular connections were inspected for corrosion processes and signs of fretting. No mechanical failure or excessive corrosion could be identified for the implants tested. The titanium releases measured were extremely low compared to in vivo and in vitro studies and were not in a critical range. PMID:19219434

Jakubowitz, Eike; Krachler, Michael; Thomsen, Marc; Heisel, Christian

2009-01-01

232

Computer-integrated revision total hip replacement surgery: concept and preliminary results.  

PubMed

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

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

233

Endodontic implants  

PubMed Central

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

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

2014-01-01

234

Endodontic implants.  

PubMed

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

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

2014-01-01

235

Application of Hemi-Hip Joint Arthroplasty  

Microsoft Academic Search

Total hip replacement and hip resurfacing arthroplasty are two popular methods for curing the diseases of hip joints to date. While the technology can be considered to be mature, there are still some problems in practice. So, another method, hemi-hip joint arthroplasty, was introduced in this paper. The structure and materials of the prothesis, its experiments in vitro and the

Lan Chen; Mingzhao Chen; Lantian Chen; Ming Hu; Yiwang Bao

2008-01-01

236

Dual-mobility acetabular components in total hip arthroplasty.  

PubMed

With dislocation being one of the most serious complications of total hip arthroplasty, prevention of recurrent instability has been the driving force behind several implant designs, including large-diameter heads, metal-on-metal bearing surfaces, and constrained acetabular components. Dual-articulation acetabular component design was similarly conceived in an effort to reduce postoperative dislocation risk. This design, developed in France in 1975 and popularized in Europe, was recently approved in the United States and represents a new surgical option for United States orthopedic surgeons performing total hip arthroplasty. In this article, we review the dual-articulation design in terms of its history, biomechanical concepts, published indications, contraindications, outcomes, and complications based on more than 20 years of largely French clinical experience. PMID:24278908

McArthur, Benjamin A; Nam, Denis; Cross, Michael B; Westrich, Geoffrey H; Sculco, Thomas P

2013-10-01

237

Surgical management of recurrent dislocation after total hip arthroplasty.  

PubMed

Dislocation is a major complication of total hip arthroplasty (THA), whose frequency has been unaffected by improvements in surgical techniques and implants. The dislocation rate depends on multiple factors related to the patient, hip disease, and surgical procedure and is therefore also dependent on the surgeon. The many published studies on THA dislocation, its causes, and its treatment have produced conflicting results. The objective of this work is to review the management of THA dislocation, which is a severe event for both the patient and the surgeon. This lecture starts with a brief review of data on THA dislocation rates and the many factors that influence them. Emphasis is then put on the evaluation for a cause and, more specifically, on the challenges raised by detecting suboptimal cup position. Next, reported techniques for treating THA dislocation and the outcomes of each are discussed. Finally, a management strategy for patients selected for revision surgery is suggested. PMID:24434366

Charissoux, J-L; Asloum, Y; Marcheix, P-S

2014-02-01

238

Hip abduction can prevent posterior edge loading of hip replacements.  

PubMed

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. PMID:23575923

van Arkel, Richard J; Modenese, Luca; Phillips, Andrew T M; Jeffers, Jonathan R T

2013-08-01

239

Artifacts in spine magnetic resonance imaging due to different intervertebral test spacers: an in vitro evaluation of magnesium versus titanium and carbon-fiber-reinforced polymers as biomaterials  

Microsoft Academic Search

Introduction  Intervertebral spacers are made of different materials, which can affect the postfusion magnetic imaging (MRI) scans. Susceptibility\\u000a artifacts especially for metallic implants can decrease the image quality. This study aimed to determine whether magnesium\\u000a as a lightweight and biocompatible metal is suitable as a biomaterial for spinal implants based on its MRI artifacting behavior.\\u000a \\u000a \\u000a \\u000a Materials and methods  To compare artifacting behaviors,

Thorsten Ernstberger; Gottfried Buchhorn; Gabert Heidrich

2009-01-01

240

Magnetic resonance imaging evaluation of intervertebral test spacers: an experimental comparison of magnesium versus titanium and carbon fiber reinforced polymers as biomaterials  

Microsoft Academic Search

Introduction  Intervertebral spacers are made of different materials, which can affect the postfusion magnetic resonance imaging (MRI) scans.\\u000a Susceptibility artifacts, especially for metallic implants, can decrease the image quality. This study aimed to determine\\u000a whether magnesium as a lightweight and biocompatible metal is suitable as a biomaterial for spinal implants based on its MRI\\u000a artifacting behavior.\\u000a \\u000a \\u000a \\u000a Materials and methods  To compare artifacting

T. Ernstberger; G. Buchhorn; G. Heidrich

2010-01-01

241

Early clinical results of a new conservative hip stem.  

PubMed

Conservative stems conserve a larger amount of bone, and due to their biomechanical effect, they allow higher compression forces on the lateral column of the femur and reduce stress shielding. Since they conserve metaphyseal bone, short stems allow the use of conventional stems when revision surgery becomes necessary. The authors present the early results of a new bone conserving stem GTS (Biomet). A total of 80 patients (55 men and 25 women) were enroled in this prospective study and received 81 GTS stem (1 bilateral). Their mean age was 64.8 years (range 43-78) at the time of surgery. The mean follow-up was 16 months (range 6-24 month). The clinical assessment was performed by a single surgeon using the Merle d'Aubigné scale; radiographic complications were described. There was one calcar fracture, which required a fixation with a screw. No cases of clinical or radiological loosening were reported. GTS Conservative hip arthroplasty stem has proven to be an excellent implant for femoral hip replacement, with expectations that it may exceed the durability of other types of implants without harming the femoral diaphysis. This may facilitate eventual stem revision and give surgeons the opportunity of using a standard primary implant. PMID:23443748

Morales de Cano, Jaime J; Gordo, Christian; Illobre, Jose M

2014-04-01

242

Investigating stress shielding spanned by biomimetic polymer-composite vs. metallic hip stem: A computational study using mechano-biochemical model.  

PubMed

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

Tavakkoli Avval, Pouria; Samiezadeh, Saeid; Klika, Václav; Bougherara, Habiba

2014-10-01

243

Cemented Total Hip Arthroplasty With Subtrochanteric Osteotomy in Dysplastic Hips  

Microsoft Academic Search

Background  Total hip arthroplasty (THA) in the presence of developmental dysplasia of the hip (DDH) can be technically challenging. Restoring\\u000a the anatomic center of hip rotation may require femoral osteotomy. Techniques using cementless components are widely reported\\u000a but less is known about using cemented components that may be more appropriate with osteopenic bone.\\u000a \\u000a \\u000a \\u000a \\u000a Questions\\/purposes  We therefore determined the rate of union, complications,

Colin R. Howie; Nicholas E. Ohly; Ben Miller

2010-01-01

244

Metal ion release after total hip replacement.  

PubMed

The concentration of cobalt (Co), chromium (Cr), molybdenum (Mo), nickel (Ni), iron (Fe) and zinc (Zn) was measured using neutron activation analysis in tissue taken from an 81 year old female at necropsy. The patient had bilateral cobalt chromium molybdenum (Co-Cr-Mo) total hip replacements: one, a metal-on-metal had been in place for 14 years, the other a metal-on-plastic for 5.5 years. Although the metal-on-metal side had become painful, the patient remained active until she died. The measurements indicated that the concentrations of Co and Cr in the lung, kidney, liver and spleen were up to fifty times "Standard Man" values. High values occurred also in the urine and in the hair. The tissue adjacent to the metal-on-metal joint was heavily laden with metal wear debris, whereas that adjacent to the metal-on-plastic joint was relatively uncontaminated. The concentration varied with distance from the implant. Co predominated in the urine, whereas Cr predominated near the implants. The existence of such high levels, especially in the organs, is a possible cause for concern. PMID:7470573

Dobbs, H S; Minski, M J

1980-10-01

245

Influence of Hip Joint Position on Muscle Activity during Prone Hip Extension with Knee Flexion  

PubMed Central

[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.

Suehiro, Tadanobu; Mizutani, Masatoshi; Okamoto, Mitsuhisa; Ishida, Hiroshi; Kobara, Kenichi; Fujita, Daisuke; Osaka, Hiroshi; Takahashi, Hisashi; Watanabe, Susumu

2014-01-01

246

Spacer process and alignment assessment for SADP process  

NASA Astrophysics Data System (ADS)

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.

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

2012-03-01

247

Improvement of pressurised aerosol deposition with Nebuhaler spacer device.  

PubMed Central

The effect on aerosol deposition from a pressurised metered dose inhaler of a 750 cm3 spacer device with a one way inhalation valve (Nebuhaler, Astra Pharmaceuticals) was assessed by means of an in vivo radiotracer technique. Nine patients with obstructive lung disease took part in the study. The pattern of deposition associated with use of a metered dose inhaler alone was compared with that achieved with the spacer used both for inhalation of single puffs of aerosol and for inhalation of four puffs actuated in rapid succession and then inhaled simultaneously. On each occasion there was a delay of 1 s between aerosol release and inhalation, simulating poor inhaler technique. With the metered dose inhaler alone, a mean (SEM) 8.7 (1.8)% of the dose reached the lungs and 80.9 (1.9)% was deposited in the oropharynx. With single puffs from the spacer 20.9 (1.6)% of the dose (p less than 0.01) reached the lungs, only 16.5 (2.3)% (p less than 0.01) was deposited in the oropharynx, and 55.8 (3.1)% was retained within the spacer itself. With four puffs from the spacer 15.2 (1.5)% reached the lungs (p = 0.02 compared with the metered dose inhaler alone, p less than 0.01 compared with single puffs from the spacer), 11.4 (1.2)% was deposited in the oropharynx, and 67.5 (1.8)% in the device itself. It is concluded that the spacer device gives lung deposition of metered dose aerosols comparable to or greater than a correctly used inhaler and oropharyngeal deposition is greatly reduced. The spacer should be used preferably for the inhalation of single puffs of aerosol but may also be used for the inhalation of up to four puffs actuated in rapid succession and then inhaled simultaneously. Images PMID:6440305

Newman, S P; Millar, A B; Lennard-Jones, T R; Morén, F; Clarke, S W

1984-01-01

248

Sports Activity After Total Hip Resurfacing  

Microsoft Academic Search

Background: Little is known about sports activity after total hip resurfacing.Hypothesis: Patients undergoing total hip resurfacing can have a high level of sports activity.Study Design: Case series; Level of evidence, 4.Methods: The authors evaluated the level of sports activities with a standardized questionnaire in 138 consecutive patients (152 hips) 2 years after total hip resurfacing. Range of motion, Harris hip

Marc Banerjee; Bertil Bouillon; Carolin Banerjee; Holger Bäthis; Rolf Lefering; Miriam Nardini; Joachim Schmidt

2010-01-01

249

Lifestyle and health-related quality of life in Asian patients with total hip arthroplasties.  

PubMed

Total hip arthroplasty reduces pain and restores physical function in patients with hip joint problems. This study examined lifestyle and health-related quality of life before and after total hip arthroplasty in Japanese and Chinese patients. Two hospitals in China recruited 120 patients and 120 Japanese patients matched by age and operative status were drawn from a prospective cohort database. Oxford Hip Score, EuroQol, and characteristics of Asian lifestyle and attitudes toward the operation were assessed. There were no differences between patients from the two countries in quality-of-life-scale scores: postoperative patients had significantly better quality-of-life scores than preoperative patients in both countries. In China, patients who reported that living at home was inconvenient had significantly worse Oxford Hip Scores than those who did not. Mean scores for anxiety items concerning possible dislocation and durability of the implant were significantly higher in Japanese than in Chinese subjects. Our findings suggest that providing information about housing conditions and lifestyles would result in improved quality of life and reduced anxiety in patients with implanted joints. PMID:24845456

Fujita, Kimie; Xia, Zhenlan; Liu, Xueqin; Mawatari, Masaaki; Makimoto, Kiyoko

2014-09-01

250

[Implant allergies].  

PubMed

An increasing number of patients receive and benefit from osteosynthesis materials or artificial joint replacement. The most common complications are mechanical problems or infection. Metals like nickel, chromium and cobalt as well as bone cement components like acrylates and gentamicin are potential contact allergens which can cause intolerance reactions to implants. Eczema, delayed wound/bone healing, recurrent effusions, pain and implant loosening all have been described as manifestation of implant allergy. In contrast to the high incidence of cutaneous metal allergy, allergies associated with implants are rare. Diagnosis of metal implant allergy is still difficult. Thus differential diagnoses--in particular infection--have to be excluded and a combined approach of allergologic diagnostics by patch test and histopathology of peri-implant tissue is recommended. It is still unknown which conditions induce allergic sensitization to implants or trigger peri-implant allergic reactions in the case of preexisting cutaneous metal allergy. Despite the risk of developing complications being unclear, titanium based osteosynthesis materials are recommended for metal allergic patients and the use of metal-metal couplings in arthroplasty is not recommended for such patients. If the regular CoCr-polyethylene articulation is employed, the patient should give informed written consent. PMID:20204719

Thomas, P; Thomsen, M

2010-03-01

251

Fabricating specialised orthopaedic implants using additive manufacturing  

NASA Astrophysics Data System (ADS)

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.

Unwin, Paul

2014-03-01

252

Nuclear reactor spacer grid and ductless core component  

DOEpatents

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.

Christiansen, David W. (Kennewick, WA); Karnesky, Richard A. (Richland, WA)

1989-01-01

253

Ultrasound-Assisted Hip Arthroscopy  

PubMed Central

We describe the use of intraoperative ultrasound for the safe development of arthroscopic portals during hip arthroscopy without the requirement for fluoroscopy. We find this technique consistently accurate, allowing the safe introduction of arthroscopic instruments into the hip with a very low rate of iatrogenic injury. We have further developed the technique for application to both central- and peripheral-compartment procedures. We now have a total experience of more than 700 procedures to date. With the described technique of ultrasound guidance for portal placement, fluoroscopy is required in fewer than 2% of hip arthroscopy procedures at our institution. PMID:24904772

Weinrauch, Patrick; Kermeci, Sharon

2014-01-01

254

Anterior minimally invasive approach for total hip replacement: five-year survivorship and learning curve.  

PubMed

Opponents associate minimally invasive total hip replacement (THR) with additional risks, potentially resulting in increased implant failure rates. The purpose was to document complications, quality of implant positioning and five-year survivorship of THR using the AMIS approach and to test the hypothesis that eventual high complication and revision rates would be limited to an early series and be avoided by junior surgeons who get trained by a senior surgeon. A consecutive series of 150 primary THR implanted during the introduction of the AMIS technique in the department was retrospectively analysed for complications, implant positioning and implant survival after a minimum of five years. Survivorship curves of implants were compared between different surgeons and time periods. Due to implant revision for any reason the five-year survival rate was 94.6%, 78.9% for the first 20 and 96.8% for the following 130 AMIS procedures (p = 0.001). The hazard ratio for implant failure was 0.979 indicating a risk reduction of 2% every further case. The five-year implant survivorship of those procedures performed by two junior surgeons was 97.7%. We conclude that adoption of AMIS temporarily exposed patients to a higher risk of implant revisions, which normalised after the first 20 cases and that experience from a single surgeon's learning curve could effectively be taught to junior surgeons. PMID:24500832

Müller, Daniel A; Zingg, Patrick O; Dora, Claudio

2014-01-01

255

Future Bearing Surfaces in Total Hip Arthroplasty  

PubMed Central

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

2014-01-01

256

Development of a surgical robot for cementless total hip arthroplasty.  

PubMed

The long-term success of cementless total hip arthroplasty (THA) may depend on bone ingrowth into the porous-fixation surfaces of the implant. The ingrowth process is facilitated when the surgeon achieves a satisfactory fit for the prosthesis. Clinically or roentgenographically visible failure and persistent thigh pain after cementless THA remain significant problems, both of which may be alleviated by more precise preparation of the femoral canal and selection of an appropriately sized prosthesis. The objective of this study was to obtain an exact fit for the prosthesis through the use of an image-directed surgical robot for femoral canal preparation. PMID:1446455

Paul, H A; Bargar, W L; Mittlestadt, B; Musits, B; Taylor, R H; Kazanzides, P; Zuhars, J; Williamson, B; Hanson, W

1992-12-01

257

Prosthetic total disk replacement--can we learn from total hip replacement?  

PubMed

Total lumbar disk replacement has become a routine procedure in many countries. However, discussions regarding its use are ongoing. Issues focus on patient selection, technical limitations, and avoidance or management of complications or long-term outcomes. A review of the development of this technology, since the development of the first successful implantation of a total lumbar disk prosthesis in 1984, shows an amazing analogy to the history of total hip replacement. This article is a one-to-one comparison of the evolution of total hip and total lumbar disk replacement from "skunk works" to scientific evidence. PMID:21944590

Mayer, H Michael; Siepe, Christoph J

2011-10-01

258

Cochlear implants.  

PubMed

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

Macherey, Olivier; Carlyon, Robert P

2014-09-22

259

Hip Resurfacing Arthroplasty in Treatment of Avascular Necrosis of the Femoral Head  

PubMed Central

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

Pyda, Micha?; Koczy, Bogdan; Widuchowski, Wojciech; Widuchowska, Ma?gorzata; Sto?tny, Tomasz; Mielnik, Micha?; Hermanson, Jacek

2015-01-01

260

Hip resurfacing arthroplasty in treatment of avascular necrosis of the femoral head.  

PubMed

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 and 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

Pyda, Micha?; Koczy, Bogdan; Widuchowski, Wojciech; Widuchowska, Ma?gorzata; Sto?tny, Tomasz; Mielnik, Micha?; Hermanson, Jacek

2015-01-01

261

Friction in hip prostheses.  

PubMed

Although the reduction of frictional torques was the driving force behind the design of the Charnley prosthesis, later concerns about wear and subsequent loosening of this and other hip replacements have dominated debate within the bioengineering community. To stimulate discussion on the role of friction in loosening, a review of the frictional characteristics of different prostheses was undertaken. The use of simple laboratory screening-type machines in the frictional assessment of different material combinations is discussed together with experiments performed on single axis simulators using both conventional and experimental prostheses. In particular, recent developments in the use of soft layer components are highlighted. Further, the possible link between excessively high frictional torques and loosening is discussed in the light of current results obtained from explanted prostheses. PMID:9239463

Hall, R M; Unsworth, A

1997-08-01

262

What Is a Hip Replacement?  

MedlinePLUS

... longer and cause less inflammation. Less common problems after surgery are: Infection Blood clots Bone growth past the normal edges of the bone. Risks of problems after hip replacement surgery are much lower than they used to be. ...

263

Location of membrane-bound hapten with different length spacers.  

PubMed Central

Immunogenic activity of a lipid hapten is strongly dependent of the length and nature of the linker chain (spacer) connecting the hapten to the head group of the lipid. A derivative containing a very short or a long spacer is known to be less effective for antibody binding than that of an intermediate length. In the present experiment, this was confirmed first by experiments of antibody binding to TNP lipid haptens with different length of spacers and of antibody-dependent macrophage binding to them. Second, we determined the location of the TNP haptens in lipid bilayer membranes by fluorescence energy transfer. It was found that vertical distances between TNP groups (acceptors), which were assumed to be randomly distributed in a plan parallel to the membrane surface, and a pyrene fluorophore (donor), which was embedded in the middle of lipid membranes, were 10.2-10.5 A in the DMPC membranes and 13.2-13.9 A in the DPPC membranes. The vertical distances were about 3 A longer in the DPPC membranes than in the DMPC membranes. However, they were almost independent of the length of spacers. This indicates that TNP residues of the lipid haptens locate at the similar vertical position on the membrane surfaces even if they have different length spacers. From these results we suggested that the affinity of the spacer groups to the bilayer surfaces can modulate the binding affinity of antibody to lipid hapten on the membrane surfaces. This was partly supported by the binding experiments of TNP spacers to the bilayer membranes. PMID:2307487

Kimura, K; Arata, Y; Yasuda, T; Kinosita, K; Nakanishi, M

1990-01-01

264

Can periprosthetic hip joint infections be successfully managed by debridement and prosthesis retention?  

PubMed Central

To evaluate the current literature about how successfully periprosthetic hip joint infections can be managed by debridement and prosthesis retention. A literature search was performed through PubMed until September 2013. Search terms were “DAIR (debridement, antibiotics, irrigation, and retention)” alone and in combination with “hip” as well as “hip infection + prosthesis retention”. A total of 11 studies reporting on 292 cases could be identified. Five different treatment modalities have been described with varying success rates (debridement-21% infection eradication rate; debridement + lavage-75% infection eradication rate; debridement, lavage, with change of modular prosthesis components-70.4% infection eradication rate; debridement, lavage, change of modular prosthesis components + vacuum-assisted closure-92.8% infection eradication rate; acetabular cup removal + spacer head onto retained stem-89.6% infection eradication rate). With regard to the postoperative antibiotic therapy, no general consensus could be drawn from the available data. Debridement, antibiotic therapy, irrigation, and prosthesis retention is an acceptable solution in the management of early and acute hematogenous periprosthetic hip joint infections. The current literature does not allow for generalization of conclusions with regard to the best treatment modality. A large, multi-center study is required for identification of the optimal treatment of these infections. PMID:25035823

Anagnostakos, Konstantinos; Schmitt, Cornelia

2014-01-01

265

Breast Implants  

MedlinePLUS

... Vaccines, Blood & Biologics Animal & Veterinary Cosmetics Tobacco Products Medical Devices Print this page Share this page E-mail this page Home Medical Devices Products and Medical Procedures Implants and Prosthetics Breast ...

266

Metrology characterization of spacer double patterning by scatterometry  

NASA Astrophysics Data System (ADS)

Spacer defined double patterning processes consists of multiple deposition, post strips and etch steps and is inherently susceptible to the cumulative effects of defects from each process step leading to higher rate of defect detection. CD distortions and CD non-uniformity leads to DPT overlay errors. This demands improved critical dimension uniformity (CDU) and overlay control. Scatterometry technique enables the characterization and control the CD uniformity and provision to monitor stepper and scanner characteristics such as focus and dose control. While CDSEM is capable of characterizing CD and sidewall angle, is not adequate to resolve shape variations, such as footing and top rounding and spacers with leaning angles, during the intermediate process steps. We will characterize direct low temperature oxide deposition on resist spacer with fewer core films and reduced number of processing and metrology control steps. Metrology characterization of SADP and resist core transferred spacers at various process steps will be performed by scatterometry using spectroscopic ellipsometry and reflectometry. We will present CD distribution (CDU) and profile characterization for core formation, spacer deposition and etch by advanced optical scatterometry and also validate against CDSEM.

Dasari, Prasad; Li, Jie; Hu, Jiangtao; Liu, Zhuan; Kritsun, Oleg; Volkman, Catherine

2011-03-01

267

Silent soft tissue pathology is common with a modern metal-on-metal hip arthroplasty  

PubMed Central

Background and purpose Adverse reactions to metal debris have been reported to be a cause of pain in metal-on-metal hip arthroplasty. We assessed the incidence of both symptomatic and asymptomatic adverse reactions in a consecutive series of patients with a modern large-head metal-on-metal hip arthroplasty. Methods We studied the early clinical results and results of routine metal artifact-reduction MRI screening in a series of 79 large-head metal-on-metal hip arthroplasties (ASR; DePuy, Leeds, UK) in 68 patients. 75 hips were MRI scanned at mean 31 (12–52) months after surgery. Results 27 of 75 hips had MRI-detected metal debris-related abnormalities, of which 5 were mild, 18 moderate, and 4 severe. 8 of these hips have been revised, 6 of which were revised for an adverse reaction to metal debris, diagnosed preoperatively with MRI and confirmed histologically. The mean Oxford hip score (OHS) for the whole cohort was 21. It was mean 23 for patients with no MRI-based evidence of adverse reactions and 19 for those with adverse reactions detected by MRI. 6 of 12 patients with a best possible OHS of 12 had MRI-based evidence of an adverse reaction. Interpretation We have found a high early revision rate with a modern, large-head metal-on-metal hip arthroplasty. MRI-detected adverse rections to metal debris was common and often clinically “silent”. We recommend that patients with this implant should be closely followed up and undergo routine metal artifact-reduction MRI screening. PMID:21504335

2011-01-01

268

The role of fretting damage in total hip arthroplasty with modular design hip joints -evaluation of retrieval studies and experimental simulation methods.  

PubMed

Retrieval studies of total hip arthroplasty were reviewed to assess the clinical relevance of fretting damage on the clinical outcome of total hip arthroplasty with modular design artificial hip joints. In this case, fretting denotes the small rel-ative displacement between the two contacting surfaces at the taper joint of a modular hip prosthesis under cyclic loading caused by walking. Fretting causes a local disruption of the passivation surface layer exposing new metal to the aggressive body envi-ronment. The most important consequence is the release of metal ions and small particles. In spite of evidence that fretting plays a role in the corrosion of taper joints in modular hip implants, the statistics of the retrieval studies is too poor for a quantita-tive assessment. Moreover, the complexity of interacting mechanical loading, surface damage and corrosion leads to apprecia-ble difficulties in the experimental description of the phenomenon and the terminology used. A rather exhaustive list of experi-mental methods for in vitro fretting testing is presented. The difficulties related with accelerated testing using excessive dis-placement amplitudes or high frequencies are discussed. The necessity for alternative methods that allow in situ monitoring of metal ion and particle release with sufficient sensitivity under meaningful experimental conditions has been underlined. As an alternative to electrochemical methods, the possibility to measure subnanogram material release by using radiotracer techniques is demonstrated. (Journal of Applied Biomaterials & Biomechanics 2004; 2: 121-35). PMID:20803429

Schaaff, P

2004-01-01

269

A new method of trochanteric fixation after osteotomy in revision total hip arthroplasty with a calcar replacement femoral component  

Microsoft Academic Search

Two series of cementless revision hip arthroplasties, using a transtrochanteric approach and an identical calcar replacement femoral prosthesis, were compared to ascertain the rate of trochanteric union and device problems. The failed implants removed at the time of revision were short-stemmed cemented or cementless designs in comparable patient populations. Eighteen patients had a traditional wiring fixation with a 72% union

Roger H. Emerson; William C. Head; Linda L. Higgins

2001-01-01

270

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

Code of Federal Regulations, 2012 CFR

...device intended to be implanted to replace a hip joint. This device limits translation and rotation in one or more planes via the geometry of its articulating surfaces. It has no linkage across-the-joint. The two-part femoral component consists of...

2012-04-01

271

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

...device intended to be implanted to replace a hip joint. This device limits translation and rotation in one or more planes via the geometry of its articulating surfaces. It has no linkage across-the-joint. The two-part femoral component consists of...

2014-04-01

272

Cobalt chromium molybdenum metal combination for modular hip prostheses.  

PubMed

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

Schmidt, M; Weber, H; Schön, R

1996-08-01

273

Osseointegration of Fitmore stem in total hip arthroplasty.  

PubMed

Currently, an increasing number of younger patients undergo total hip arthroplasty surgery. This has led to a minimal invasive approach and the use of short, bone preserving, femoral stems. In this study, we sought to evaluate osseointegration of the Fitmore stem (Zimmer, Inc; Warsaw, IN) during the first 12 mo after surgery, which reflects the biological phenomenon of osseointegration with radiographic evaluation and bone densitometry (dual-energy X-ray absorptiometry). We evaluated 33 patients (mean age 62.3) using dual-energy X-ray absorptiometry scan around the stem and X-ray. Moreover, we studied functional recovery using the Harris Hip Score, timed up and go test, and a quality of life form (SF-36), during the follow-up period. At 12 mo, we observed an increased periprosthetic bone mineral density in region of interest 1 (1.7%) and region of interest 7 (8.3%), where there is usually a greater amount of bone resorption. Also Harris Hip Score, timed up and go test, and SF-36 showed an improvement of clinical conditions of all patients. We also used a control group with a standard stem implanted. Because this is the first study correlating osseointegration and clinical outcome of the Fitmore stem, further clinical studies will be necessary to confirm good/positive results and a long stable fixation. PMID:24613452

Gasbarra, Elena; Celi, Monica; Perrone, Fabio L; Iundusi, Riccardo; Di Primio, Luigia; Guglielmi, Giuseppe; Tarantino, Umberto

2014-01-01

274

[Longterm results of poldi hip replacement.].  

PubMed

The authors evaluated 124 patients operated on by means of cemented Poldi THR in the period 1980-1986 on average 14,2 years after the primary implantation (12,2-18,0). Average age of patients was 55 years (in the range of 33 to 75). Pre-operative diagnosis was osteoarthritis in 78 cases and rheumatoid arthritis in 46 patients. All patients had normal anatomical relations. The implants applied included a 49 mm polyethylene cup and a bananashaped CoCr polished stem with 32 mm head with the use of 1st generation method of cementing. Harris Hip Score averaged prior to the surgery 49 (19-52) and after the surgery 68 (49-98). In 59 patients Harris Hip Score was above 70 points. In total, 10 revision surgeries were performed of which 9 due to aseptic loosening (the cup - 6times, the cup and the stem - twice, the stem - once) and 1 due to septic loosening. There were 23 cases of evident loosening of the cup (of which 8 symptomatic and 15 asymptomatic one) and 8 probable. The number of potential operations of the cup is 46 and that of the stem 11. Combined prevalence of revision surgeries accomplished and potential is 54 (43,5 %) in case of the cup and 14 (11,2 %) in case of the stem. The survival rate after 14 years is 81,5 % in the acetabular cup and 95,2 % in case of the stem. Authors found out an increased number of THR failure after 12 years due to aseptic loosening of the acetabular cup. After the Kaplan-Maier curve the survival rate of THR after 4 years is 99 %, after 8 years 97 %, after 10 years 94 %, after 12 years 91 % and after 15 years 76 %. Linear polyethylene wear of the cup is on average 0,14 mm annually, and the volumetric one amounts to 189 cubic mm annually. Key words: THR, longterm results. PMID:20478142

Hart, R; Rozkydal, Z

1999-01-01

275

Impact of Polycarbonate Spacers on Resistive Plate Chamber Efficiencies  

NASA Astrophysics Data System (ADS)

The PHENIX experiment at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory will measure the flavor dependent quark and anti-quark polarizations in the proton through parity violating W-production. A new dedicated muon trigger spectrometer is being built to select high momentum muons from the decay of W bosons. The muon spectrometer relies on Resistive Plate Chambers (RPCs) developed for the CMS experiment at the Large Hadron Collider. PHENIX continues to pursue detailed studies of CMS RPC technology to ensure that these detectors will be optimally deployed and operated in PHENIX. In this poster we present two dimensional efficiency measurements with cosmic rays in RPC prototypes. In particular we have studied the impact polycarbonate spacers used to define the 2 mm wide RPC gas gaps have on the detector efficiency. We will present two dimensional efficiency measurements in the region adjacent to the spacers including the radial dependence of the efficiency with respect to the center of the spacer.

Mucia, Nicholas

2008-10-01

276

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

PubMed Central

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

2013-01-01

277

Hylamer vs conventional polyethylene in primary total hip arthroplasty: a long-term case-control study of wear rates and osteolysis.  

PubMed

The long-term results of Hylamer implants have not been reported previously. Clinical and radiographic results of a consecutive series of 43 patients (45 hips) who had primary total hip arthroplasty using Hylamer liners were compared with those of 37 patients (43 hips) who had conventional liners after 10-year follow-up. The linear wear rates for Hylamer and conventional polyethylene acetabular liners were 0.21 and 0.20 mm/y, respectively. The number of pelvic osteolytic lesions and their size detected on plain radiographs were significantly greater for Hylamer liners. Seven Hylamer hips were revised or are pending revision for osteolysis (16%) compared with 1 control hip. Close radiographic surveillance of patients who have Hylamer liners and evidence of osteolysis found on plain radiographs is warranted. PMID:19264443

Huddleston, James I; Harris, Alex H S; Atienza, Cesar A; Woolson, Steven T

2010-02-01

278

Long-term clinical and radiological results of the Lord total hip prosthesis. A prospective study.  

PubMed

We enrolled 98 patients (107 hips) with a mean age of 47 years (SD 8.6) into a prospective study of the Madreporic Lord THR; 34 hips had primary and 73 secondary osteoarthritis. After ten years, the survival rate using revision as the endpoint for failure was 70% (+/-9) for the cup and 98% (+/-0.3) for the stem. The combined clinical and radiological survival rates were 46% (+/-11) and 81% (+/-10), respectively. Osteoporosis due to stress-shielding was observed in the proximal femur. Hips with radiologically dense bone postoperatively showed the most pronounced bone loss. We recommend continued radiological follow-up of patients with this type of implant to allow revision to be performed before there is severe bony destruction of the pelvis. PMID:8951001

Malchau, H; Herberts, P; Wang, Y X; Kärrholm, J; Romanus, B

1996-11-01

279

Have cementless and resurfacing components improved the medium-term results of hip replacement for patients under 60 years of age?  

PubMed

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

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

2015-02-01

280

The Transcendentalist hip-hop movement.  

E-print Network

??This thesis compares and contrasts the 19th-century American Transcendentalists with modern independent Midwestern hip-hop artists. The views and works of the Transcendentalists and hip-hop music… (more)

Atwell, Justin Michael

2012-01-01

281

21M.775 Hip Hop, Spring 2003  

E-print Network

Subject explores the political and aesthetic foundations of hip hop. Students trace the musical, corporeal, visual, spoken word, and literary manifestations of hip hop over its thirty year presence in the American cultural ...

DeFrantz, Thomas

282

Image-guided, navigation-assisted Relieva Stratus MicroFlow Spacer insertion into the ethmoid sinus.  

PubMed

Anatomical complexity presents the main challenge in the administration of topical corticosteroid therapy to the paranasal sinus mucosa. This often leads to suboptimal drug delivery due to low concentrations of the therapeutic agent to the intended target area. The Relieva Stratus™ MicroFlow Spacer (Relieva Stratus) is a drug-eluting stent that is temporarily implanted into the ethmoid sinus. The reservoir of the stent is filled with triamcinolone acetonide, which is then slowly released from the device into the ethmoid sinus mucosa. The Relieva Stratus provides local and targeted delivery of the anti-inflammatory agent to the diseased mucosa. This minimally invasive implant is an option when treating ethmoid sinusitis. From January 2011 to November 2013, a total of 52 Relieva Stratus implantations into the ethmoidal cells were performed at the Department of Ear and Oral Diseases at Tampere University Hospital, Finland. C-arm fluoroscopy guidance was employed for 26 sinuses (13 patients) and optical image-guided surgery (IGS)-assisted insertions were performed on another 26 sinuses (13 patients). The accuracy of fluoroscopic insertion is not optimal, but this method is accurate enough to prevent the violation of the skull base and lamina papyracea. IGS enables the precise treatment of the diseased cells. From a technical perspective, IGS-guided insertion is a faster, safer and more exact procedure that guarantees the optimal positioning and efficacy of the implant. Moreover, IGS guidance does not entail the use of ionizing radiation. PMID:25325931

Taulu, Rami; Numminen, Jura; Bizaki, Argyro; Rautiainen, Markus

2014-10-18

283

Indications and results of hip resurfacing  

Microsoft Academic Search

The best indication for hip resurfacing is a young active patient with severe hip arthritis, good hip morphology and reasonable\\u000a bone quality. With revision of either component for any reason as the endpoint, there were 68 revisions in our series of 3,095\\u000a consecutive Birmingham Hip Resurfacings (BHR) (1997–2009), including all diagnoses in all ages. This equates to a revision\\u000a rate

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

2011-01-01

284

Optimal drug release schedule for in-situ radiosensitization of image guided permanent prostate implants  

E-print Network

tissues. Keywords: Brachytherapy, prostate, radiosensitization, modeling 1. INTRODUCTION Prostate cancer of image guided 125 I prostate brachytherapy. Spacers used in permanent implants may be manufactured from such a constraint, is not known. This work determines the optimal elution schedules for 125 I prostate brachytherapy

Sridhar, Srinivas

285

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

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 0.7mm 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 14days 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 5days post-inoculation, however the stability of the implant fixation became compromised by 10-14days 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 3mm to place a poly-methyl methacrylate spacer, with or without vancomycin. Half of the groups also received systemic vancomycin for the remaining 21days 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

Inzana, Jason A; Schwarz, Edward M; Kates, Stephen L; Awad, Hani A

2015-03-01

286

Stability of proximal femoral grafts in canine hip arthroplasty.  

PubMed

In a canine model, the fixation stability of a prosthesis and proximal bone graft composite were measured relative to the distal femur. One group had the prosthesis graft composite cemented into the distal femur. The second group had the prosthesis graft composite press fit into the distal femur for biologic ingrowth. Displacements of the proximal femoral grafts relative to the host bone in each group were measured after ex vivo (acute with graft) implantation and 4 months after implantation. A third group with no osteotomy (acute intact) simulated perfect graft to host bone union. Relative displacements representing 6 degrees freedom (translation and rotation) were calculated from the displacement values measured by 9 eddy current transducers. Measurements of displacement were used to test the hypothesis that distal press fit fixation equals distal cement fixation at 4 months after implantation. In all cases the measured translations and rotations of the graft to implant construct were small and of a magnitude that should encourage bone ingrowth (< 0.05 mm and < 0.1 degree, respectively). The stability of the press fit group at 4 months was not significantly different from the cemented group in axial and transverse displacement during axial and transverse loading, respectively. There was no difference in stabilities at 4 months between distal press fit and cemented fixation in hip replacements requiring a proximal femoral graft. PMID:9269179

Heiner, J P; Kohles, S S; Manley, P A; Vanderby, R; Markel, M D

1997-08-01

287

Developmental dysplasia of the hip  

PubMed Central

Developmental dysplasia of the hip (DDH) is a spectrum of anatomical abnormalities of the hip joint in which the femoral head has an abnormal relationship with the acetabulum. Most studies report an incidence of 1 to 34 cases per 1,000 live births and differences could be due to different diagnostic methods and timing of evaluation. Risk factors include first born status, female sex, positive family history, breech presentation and oligohydramnios. Clinical presentations of DDH depend on the age of the child. Newborns present with hip instability, infants have limited hip abduction on examination, and older children and adolescents present with limping, joint pain, and/or osteoarthritis. Repeated, careful examination of all infants from birth and throughout the first year of life until the child begins walking is important to prevent late cases. Provocative testing includes the Barlow and Ortolani maneuvers. Other signs, such as shorting of the femur with hips and knees flexed (Galeazzi sign), asymmetry of the thigh or gluteal folds, and discrepancy of leg lengths are potential clues. Treatment depends on age at presentation and outcomes are much better when the child is treated early, particularly during the first six months of life. PMID:21808709

Noordin, Shahryar; Umer, Masood; Hafeez, Kamran; Nawaz, Haq

2010-01-01

288

Effect of cement fill ratio in loosening of hip implants  

PubMed Central

Femoral loosening is one of the most prevalent causes of revision orthopedic surgeries. Cement mantle thickness has been directly correlated with femoral loosening. If the mantle is too thick, there is an increased risk of radiolucent lines and inconsistent densities. Also, the more bone that is reamed out during the procedure can lead to instability, especially if the quality of the bone is compromised due to osteoporosis. Too thin of a mantle can lead to a higher probability for cement fracture, loosening the prosthetic even further. This study has shown that there is an ideal thickness range between two to five that should be kept. From radiographic images one can measure the thickness of the cement mantle showing the loosening characteristics. PMID:23507806

Gunn, Elizabeth; Gundapaneni, Dinesh; Goswami, Tarun

2012-01-01

289

The ten-year survival of the Birmingham hip resurfacing: an independent series.  

PubMed

Recent events have highlighted the importance of implant design for survival and wear-related complications following metal-on-metal hip resurfacing arthroplasty. The mid-term survival of the most widely used implant, the Birmingham Hip Resurfacing (BHR), has been described by its designers. The aim of this study was to report the ten-year survival and patient-reported functional outcome of the BHR from an independent centre. In this cohort of 554 patients (646 BHRs) with a mean age of 51.9 years (16.5 to 81.5) followed for a mean of eight years (1 to 12), the survival and patient-reported functional outcome depended on gender and the size of the implant. In female hips (n = 267) the ten-year survival was 74% (95% confidence interval (CI) 83 to 91), the ten-year revision rate for pseudotumour was 7%, the mean Oxford hip score (OHS) was 43 (SD 8) and the mean UCLA activity score was 6.4 (SD 2). In male hips (n = 379) the ten-year survival was 95% (95% CI 92.0 to 97.4), the ten-year revision rate for pseudotumour was 1.7%, the mean OHS was 45 (SD 6) and the mean UCLA score was 7.6 (SD 2). In the most demanding subgroup, comprising male patients aged < 50 years treated for primary osteoarthritis, the survival was 99% (95% CI 97 to 100). This study supports the ongoing use of resurfacing in young active men, who are a subgroup of patients who tend to have problems with conventional THR. In contrast, the results in women have been poor and we do not recommend metal-on-metal resurfacing in women. Continuous follow-up is recommended because of the increasing incidence of pseudotumour with the passage of time. PMID:22933488

Murray, D W; Grammatopoulos, G; Pandit, H; Gundle, R; Gill, H S; McLardy-Smith, P

2012-09-01

290

Spontaneous modular femoral head dissociation complicating total hip arthroplasty.  

PubMed

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

Talmo, Carl T; Sharp, Kinzie G; Malinowska, Magdalena; Bono, James V; Ward, Daniel M; LaReau, Justin

2014-06-01

291

Bone sarcoma diagnosed at the time of reconstructive hip surgery  

PubMed Central

Objective To describe the clinical course of a group of patients in whom sarcoma of the proximal femur was diagnosed at the time of reconstructive hip surgery. Design A retrospective case series. Setting Final management of all patients took place at a tertiary care centre. Patients and Interventions Six consecutive patients with sarcoma of the proximal femur diagnosed at the time of reconstructive hip surgery. The mistaken diagnoses made before surgery were benign tumour (2 patients), avascular necrosis (2 patients), subtrochanteric fracture due to metastasis (1 patient) and granuloma from a loose hip implant (1 patient). The final diagnosis was osteosarcoma in 3 patients and chondrosarcoma in 3. Three patients with high-grade sarcoma received neoadjuvant chemotherapy followed by femoral or pelvic resection, or both, and reconstruction. Two patients with chondrosarcoma underwent wide excision of the tumour with allograft or modular implant reconstruction. One patient with widespread metastasis received only palliative chemotherapy. Main outcome measures Overall survival with respect to oncologic and functional results of treatment. Results Two patients (1 who received only palliative chemotherapy) died after 5 and 21 months’ follow-up, respectively. Average follow-up for the remaining 4 patients was 65.2 months (range from 51 to 75 months). They were disease free at latest follow-up. One patient required amputation for septic complications related to the reconstruction. Conclusions Limb salvage surgery for sarcoma of the proximal femur is challenging when the diagnosis is made at the time of reconstructive surgery rather than through an appropriately planned biopsy. However, this series suggests that limb preservation is feasible and that hindquarter amputation is not the only solution. PMID:9711160

Dowdy, Paul A.; Griffin, Anthony M.; White, Lawrence M.; Wunder, Jay S.; Bell, Robert S.

1998-01-01

292

Hip-Hop and the Academic Canon  

ERIC Educational Resources Information Center

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…

Abe, Daudi

2009-01-01

293

Imaging of the Painful Hip and Pelvis  

Microsoft Academic Search

Many exciting new advances in our knowledge of the hip and its pathologic processes have occurred during the past several years. With the use of magnetic resonance (MR), MR arthrography and with improvements in arthroscopy and surgery of the hip we continue to improve our understanding of the hip. Current topics of interest include imaging of the acetabular labrum, femoroacetabular

C. W. A. Pfirrmann; C. A. Petersilge

294

Outcomes of post-operative periprosthetic femur fracture around total hip arthroplasty: a review.  

PubMed

As the number of primary total hip arthroplasties increase over the next several decades so will the incidence of periprosthetic fractures around the femoral stem. Treatment can reliably be predicted using the Vancouver classification with internal fixation being indicated in fractures involving a stable implant and revision arthroplasty indicated in those with unstable prostheses. Non-displaced fractures involving the greater and lesser trochanter can generally be treated non-operatively. Extensively porous-coated stems and the use of modular uncemented revision stems to treat Vancouver B fractures have shown encouraging results. The treatment of Vancouver C periprosthetic fractures continues to follow basic AO fixation principles with an emphasis on eliminating stress risers with adequate implant overlap and length. This review will focus on the risk factors and classification of these fractures, as well as highlight the treatment options for post-operative periprosthetic femoral fractures around a total hip arthroplasty. PMID:25209073

Wu, Eddie S; Cherian, Jeffrey J; Kapadia, Bhaveen H; Banerjee, Samik; Jauregui, Julio J; Mont, Michael A

2015-01-01

295

Design of custom hip stem prostheses using three-dimensional CT modeling.  

PubMed

Long life expectancy, demand for high activity levels, and bone loss at the time of revision motivate the search for reliable and successful noncemented hip stem designs. It is hypothesized that improved implant fit may increase the longevity of noncemented total joints. Quantitative X-ray CT has enabled the use of a computerized stem design program, which designs an optimal-fit hip stem for individual femurs. Computed tomography and interactive image processing methods are used to generate the individual three-dimensional femoral models, which are used by the stem design program. Optimal-fit design provides maximum stem-bone contact while satisfying the requirement of being surgically insertable. Previous methods of custom implant design, including those that use three-dimensional CT modeling, have not provided optimal stem-bone fit. Quantitative results of this new process are presented. PMID:3655042

Robertson, D D; Walker, P S; Granholm, J W; Nelson, P C; Weiss, P J; Fishman, E K; Magid, D

1987-01-01

296

How Do Metal Ion Levels Change over Time in Hip Resurfacing Patients? A Cohort Study  

PubMed Central

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

Savarino, Lucia; Cadossi, Matteo; Chiarello, Eugenio; Fotia, Caterina; Greco, Michelina; Baldini, Nicola; Giannini, Sandro

2014-01-01

297

Corail uncemented hemiarthroplasty with a Cathcart head for intracapsular hip fractures.  

PubMed

The National Institute for Health and Clinical Excellence (NICE) guidelines from 2011 recommend the use of cemented hemi-arthroplasty for appropriate patients with an intracapsular hip fracture. In our institution all patients who were admitted with an intracapsular hip fracture and were suitable for a hemi-arthroplasty between April 2010 and July 2012 received an uncemented prosthesis according to our established departmental routine practice. A retrospective analysis of outcome was performed to establish whether the continued use of an uncemented stem was justified. Patient, surgical and outcome data were collected on the National Hip Fracture database. A total of 306 patients received a Cathcart modular head on a Corail uncemented stem as a hemi-arthroplasty. The mean age of the patients was 83.3 years (SD 7.56; 46.6 to 94) and 216 (70.6%) were women. The mortality rate at 30 days was 5.8%. A total of 46.5% of patients returned to their own home by 30 days, which increased to 73.2% by 120 days. The implant used as a hemi-arthroplasty for intracapsular hip fracture provided satisfactory results, with a good rate of return to pre-injury place of residence and an acceptable mortality rate. Surgery should be performed by those who are familiar with the design of the stem and understand what is required for successful implantation. PMID:24151276

Kendrick, B J L; Wilson, H A; Lippett, J E; McAndrew, A R; Andrade, A J M D

2013-11-01

298

Mechanical failure of metal-polyethylene sandwich liner in metal-on-metal total hip replacement.  

PubMed

Metal-on-metal had been proposed as an optimal articulation in THRs, however, many monoblock prostheses have been recalled in the USA because of significant high rates of early failure. Metal-on-metal prostheses had been implanted in our institution, and this is a case history of a single patient, in whom metal-on-metal THRs with different femoral sizes of heads were implanted. A 57-year-old female patient underwent bilateral total hip replacements with metal-on-metal prostheses using metal-polyethylene "sandwich" liners 9 years ago on the right side and 7 years ago on the left side respectively. The only difference in both sides was the femoral head diameter of 28 mm in right and 34 mm in left. Seven years after the left surgery, the acetabular liner was dissociated, however, metallosis was not detected. Although the larger femoral head was thought to increase hip joint stability, it dictated a reduction in polyethylene thickness in this prosthesis design, and it was 4 mm in the left hip. Recently, metal-on-metal articulations are thought not to be optimal for hip joint bearing surface, however, this clinical failure was due to the polyethylene thickness and quality. PMID:25601670

Oshima, Yasushi; Fetto, Joseph F

2015-01-01

299

Ion Implant  

NSDL National Science Digital Library

This website includes an animation which illustrates the ion implant process. Objective: Name the three common dopants used in implantation processes and explain the process of generating an ion beam from source to wafer. You can find this animation under the heading "Process & Equipment III." This simulation is from Module 026 of the Process & Equipment III Cluster of the MATEC Module Library (MML). To view other clusters or for more information about the MML visit http://matec.org/ps/library3/process_I.shtmlKey

2012-10-04

300

Does Femoral Component Loosening Predispose to Femoral Fracture?: An In Vitro Comparison of Cemented Hips  

Microsoft Academic Search

The incidence of femur fracture around total hip arthroplasties continues to increase at substantial cost to society. These\\u000a fractures are frequently associated with a loose femoral component. Consequently, we sought to test whether femoral component\\u000a loosening predisposes to periprosthetic femoral fracture. Because many periprosthetic femoral fractures are spiral in nature,\\u000a we evaluated the torsional characteristics of the implanted femur in

Barton Harris; John R. Owen; Jennifer S. Wayne; William A. Jiranek

2010-01-01

301

Long-term results of the threaded Weill cup in primary total hip arthroplasty  

Microsoft Academic Search

Uncemented, threaded acetabular components with smooth surface treatment were widely used in continental Europe in the 1970s\\u000a and 1980s for primary total hip arthroplasty (THA). Previously published studies showed high failure rates in the mid-term.\\u000a In a consecutive series of 116 patients, 127 threaded cups with smooth surface treatment (Weill cup; Zimmer, Winterthur, Switzerland)\\u000a were implanted in combination with one

Michael Clarius; Alexander W. Jung; Patric Raiss; Marcus R. Streit; Christian Merle; Peter R. Aldinger

2010-01-01

302

CupAlign: Computer-Assisted Postoperative Radiographic Measurement of Acetabular Components Following Total Hip Arthroplasty  

Microsoft Academic Search

\\u000a Clinical problems following total hip replacement surgery, such as dislocation and implant wear, remain as significant clinical\\u000a problems with many contributing factors. Although it is intuitive to surgeons that acetabular component alignment is one important\\u000a factor, large clinical series have produced conflicting results with respect to cup alignment as a risk factor in predisposing\\u000a to dislocation. One reason is that

Branislav Jaramaz; Constantinos Nikou; Timothy J. Levison; Anthony M. Digioia; Richard S. Labarca

1999-01-01

303

Filter holder assembly having extended collar spacer ring  

DOEpatents

A filter holder assembly is provided that utilizes a fail-safe regenerator unit with an annular spacer ring having an extended metal collar for containment and positioning of a compliant ceramic gasket used in the assembly. The filter holder assembly is disclosed for use with advanced composite, filament wound, and metal candle filters.

Alvin, Mary Anne (Pittsburgh, PA); Bruck, Gerald J. (Murrysville, PA)

2002-01-01

304

Heat transfer near spacer grids in rod bundles  

Microsoft Academic Search

Heat transfer data from several sources have been assembled which show the effect of spacer grids on local heat transfer within a rod bundle. Both single phase (air and steam) data and two phase (steam\\/water) data show heat transfer augmentation in the grid region. Heat transfer improvement immediately beyond the grid ranges from a few percent to over fifty percent

Yoder

1985-01-01

305

Mathematical modeling of spacer fabrics under impulsive loading  

Microsoft Academic Search

In this research, a model has been provided to predict the damping behavior of spacer fabrics against impact forces. These fabrics were modeled as lumped mass and spring system. Because of damping force in mechanical systems, a dashpot has been added to the system for producing the damping force. Therefore, mathematical modeling of the vibration system led to a differential

Forough Arabzadeh; Mohammad Sheikhzadeh; Mohammad Ghane; Sayyed Mahdi Hejazi

2012-01-01

306

The clinical and radiological outcomes of hip resurfacing versus total hip arthroplasty: a meta-analysis and systematic review  

PubMed Central

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

2010-01-01

307

[Hip fracture: call the geriatrician? ].  

PubMed

Hip fracture management by the geriatrician demands a close cooperation with orthopedic surgeons and a interdisciplinary approach with the implementation of protocole-driven care to standardize the care of most patients. From admission to discharge this orthogeriatric management is based on the comprehensive geriatric assessment to reduce the delays in surgery, the occurence of delirium or the most postoperative complications. This collaborative model of care seems to have the potential to improve function, admissions to nursing homes and mortality outcomes compared with usual care of geriatric patient with hip fracture. PMID:25536828

Coutaz, M

2014-11-01

308

Practical approach to hip pain.  

PubMed

Hip pain is a common complaint among patients presenting to outpatient clinics. Stratifying patients based on age, acuity, and location of pain (extra-articular vs intra-articular) can help to aid in appropriate imaging and timely referral to an orthopedic surgeon. A thorough history and an organized physical examination combined with radiographs are usually sufficient to diagnose most hip complaints. If the diagnosis remains uncertain, magnetic resonance imaging, usually with intra-articular gadolinium, is the imaging modality of choice in diagnosing both intra-articular and extra-articular pathologies. PMID:24994049

Karrasch, Christopher; Lynch, Scott

2014-07-01

309

[Tendinitis of the hip region].  

PubMed

Tendinitis and bursitis are less common around the hip than around the shoulder. Nevertheless, they must be recognized to avoid unnecessary and costly diagnostic errors. Their various clinical forms are studied in detail. Tendino-bursitis of the gluteus medius muscle is the most frequent in its subacute form, but it is rare in its acute, pseudo-gouty form. Calcification of the reflected tendon of the rectus femoris muscle often closely resembles arthritis of the hip. Synovial cysts of the psoas bursa and rupture of the gluteus medius tendon are rare but must be known. Local injections of corticosteroids play an important part in the treatment of these diseases. PMID:1857930

Samson, M; Lequesne, M

1991-06-21

310

Process optimized minimally invasive total hip replacement  

PubMed Central

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

Gebel, Philipp; Oszwald, Markus; Ishaque, Bernd; Ahmed, Gaffar; Blessing, Recha; Thorey, Fritz; Ottersbach, Andreas

2012-01-01

311

Process optimized minimally invasive total hip replacement.  

PubMed

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

Gebel, Philipp; Oszwald, Markus; Ishaque, Bernd; Ahmed, Gaffar; Blessing, Recha; Thorey, Fritz; Ottersbach, Andreas

2012-01-01

312

Effect of cup inclination on predicted contact stress-induced volumetric wear in total hip replacement.  

PubMed

In order to increase the lifetime of the total hip endoprosthesis, it is necessary to understand mechanisms leading to its failure. In this work, we address volumetric wear of the artificial cup, in particular the effect of its inclination with respect to the vertical. Volumetric wear was calculated by using mathematical models for resultant hip force, contact stress and penetration of the prosthesis head into the cup. Relevance of the dependence of volumetric wear on inclination of the cup (its abduction angle ?A) was assessed by the results of 95 hips with implanted endoprosthesis. Geometrical parameters obtained from standard antero-posterior radiographs were taken as input data. Volumetric wear decreases with increasing cup abduction angle ?A. The correlation within the population of 95 hips was statistically significant (P = 0.006). Large cup abduction angle minimises predicted volumetric wear but may increase the risk for dislocation of the artificial head from the cup in the one-legged stance. Cup abduction angle and direction of the resultant hip force may compensate each other to achieve optimal position of the cup with respect to wear and dislocation in the one-legged stance for a particular patient. PMID:24830356

Rijavec, B; Košak, R; Daniel, M; Kralj-Igli?, V; Dolinar, D

2015-10-01

313

Microscopical analysis of synovial fluid wear debris from failing CoCr hip prostheses  

NASA Astrophysics Data System (ADS)

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.

Ward, M. B.; Brown, A. P.; Cox, A.; Curry, A.; Denton, J.

2010-07-01

314

Sports hip injuries: assessment and management.  

PubMed

Over the past 10 years, the understanding, assessment, and management of hip pain and injuries in the athlete have improved. Traditionally, the evaluation of hip pain and injuries was limited to obvious disorders, such as hip arthritis and fractures, or disorders that were previously considered to be simply soft-tissue strains and contusions, such as groin pulls, hip pointers, and bursitis. Two parallel tracks of progress have improved understanding of the complexities of hip joint athletic injuries and the biomechanical basis of early hip disease. In the field of sports medicine, improved diagnostic skills now allow better interpretation of debilitating intra-articular hip disorders and their effects on core performance. In the field of hip preservation, there has been an evolution in understanding the effects of biomechanical mismatches between the femoral head and the acetabulum on the development of early hip damage, injury, and arthritis. The integration of these two parallel fields has accelerated the understanding of the importance of hip biomechanics and early hip injury in human performance and function. PMID:23395055

Kelly, Bryan T; Maak, Travis G; Larson, Christopher M; Bedi, Asheesh; Zaltz, Ira

2013-01-01

315

Effect of nitride sidewall spacer process on boron dose loss in ultrashallow junction formation  

E-print Network

Effect of nitride sidewall spacer process on boron dose loss in ultrashallow junction formation P nitride spacer process on the boron profile in silicon and the related dose loss of B from the Si; published 4 February 2004 A nitride spacer with an underlying deposited tetraethoxysilane oxide

Dunham, Scott

316

Management of congenital hip dysplasia.  

PubMed

In summary, congenital hip dysplasia remains a worldwide health problem, which has not been resolved by neonatal screening programs. The primary care physician's role is critical for early diagnosis. An understanding of the need for repeated examinations, the age related signs, and continued diligence is essential. The common use of the triple diaper treatment is not recommended. PMID:2915916

Staheli, L T

1989-01-01

317

Revision of the acetabular component in dysplastic hips previously reconstructed with a shelf autograft: study of the outcome with special assessment of bone-stock changes.  

PubMed

In this retrospective study we evaluated the proficiency of shelf autograft in the restoration of bone stock as part of primary total hip replacement (THR) for hip dysplasia, and in the results of revision arthroplasty after failure of the primary arthroplasty. Of 146 dysplastic hips treated by THR and a shelf graft, 43 were revised at an average of 156 months, 34 of which were suitable for this study (seven hips were excluded because of insufficient bone-stock data and two hips were excluded because allograft was used in the primary THR). The acetabular bone stock of the hips was assessed during revision surgery. The mean implant-bone contact was 58% (50% to 70%) at primary THR and 78% (40% to 100%) at the time of the revision, which was a significant improvement (p < 0.001). At primary THR all hips had had a segmental acetabular defect > 30%, whereas only five (15%) had significant segmental bone defects requiring structural support at the time of revision. In 15 hips (44%) no bone graft or metal augments were used during revision. A total of 30 hips were eligible for the survival study. At a mean follow-up of 103 months (27 to 228), two aseptic and two septic failures had occurred. Kaplan-Meier survival analysis of the revision procedures demonstrated a ten-year survival rate of 93.3% (95% confidence interval (CI) 78 to 107) with clinical or radiological failure as the endpoint. The mean Oxford hip score was 38.7 (26 to 46) for non-revised cases at final follow-up. Our results indicate that the use of shelf autografts during THR for dysplastic hips restores bone stock, contributing to the favourable survival of the revision arthroplasty should the primary procedure fail. PMID:23723271

Abolghasemian, M; Drexler, M; Abdelbary, H; Sayedi, H; Backstein, D; Kuzyk, P; Safir, O; Gross, A E

2013-06-01

318

Retrieval analysis of 240 metal-on-metal hip components, comparing modular total hip replacement with hip resurfacing.  

PubMed

This study compared component wear rates and pre-revision blood metal ions levels in two groups of failed metal-on-metal hip arthroplasties: hip resurfacing and modular total hip replacement (THR). There was no significant difference in the median rate of linear wear between the groups for both acetabular (p = 0.4633) and femoral (p = 0.0872) components. There was also no significant difference in the median linear wear rates when failed hip resurfacing and modular THR hips of the same type (ASR and Birmingham hip resurfacing (BHR)) were compared. Unlike other studies of well-functioning hips, there was no significant difference in pre-revision blood metal ion levels between hip resurfacing and modular THR. Edge loading was common in both groups, but more common in the resurfacing group (67%) than in the modular group (57%). However, this was not significant (p = 0.3479). We attribute this difference to retention of the neck in resurfacing of the hip, leading to impingement-type edge loading. This was supported by visual evidence of impingement on the femur. These findings show that failed metal-on-metal hip resurfacing and modular THRs have similar component wear rates and are both associated with raised pre-revision blood levels of metal ions. PMID:21357950

Matthies, A; Underwood, R; Cann, P; Ilo, K; Nawaz, Z; Skinner, J; Hart, A J

2011-03-01

319

In-vivo degradation of poly(carbonate-urethane) based spine implants  

PubMed Central

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

Cipriani, E.; Bracco, P.; Kurtz, S.M.; Costa, L.; Zanetti, M.

2013-01-01

320

Cover Story: The Miseducation of Hip-Hop.  

ERIC Educational Resources Information Center

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,…

Evelyn, Jamilah

2000-01-01

321

Incidence of infection with the use of non-irradiated morcellised allograft bone washed at the time of revision arthroplasty of the hip.  

PubMed

Implantation of allograft bone is an integral part of revision surgery of the hip. One major concern with its use is the risk of transmission of infective agents. There are a number of methods of processing allograft bone in order to reduce this risk. One method requires washing the tissue using pulsed irrigation immediately before implantation. We report the incidence of deep bacterial infection in 138 patients (144 revision hip arthroplasties) who had undergone implantation of allograft bone. The bone used was fresh-frozen, non-irradiated and pulse-washed with normal saline before implantation. The deep infection rate at a minimum follow-up of one year was 0.7%. This method of processing appears to be associated with a very low risk of allograft-related bacterial infection. PMID:16260672

Kwong, F N K; Ibrahim, T; Power, R A

2005-11-01

322

A multicenter approach evaluating the impact of vitamin e-blended polyethylene in cementless total hip replacement.  

PubMed

Since polyethylene is one of the most frequently used biomaterials as a liner in total hip arthroplasty, strong efforts have been made to improve design and material properties over the last 50 years. Antioxidants seems to be a promising alternative to further increase durability and reduce polyethylene wear in long term. As of yet, only in vitro results are available. While they are promising, there is yet no clinical evidence that the new material shows these advantages in vivo. To answer the question if vitamin-E enhanced ultra-high molecular weight polyethylene (UHMWPE) is able to improve long-term survivorship of cementless total hip arthroplasty we initiated a randomized long-term multicenter trial. Designed as a superiority study, the oxidation index assessed in retrieval analyses of explanted liners was chosen as primary parameter. Radiographic results (wear rate, osteolysis, radiolucency) and functional outcome (Harris Hip Scores, University of California-Los Angeles, Hip Disability and Osteoarthritis Outcome Score, Visual Analogue Scale) will serve as secondary parameters. Patients with the indication for a cementless total hip arthroplasty will be asked to participate in the study and will be randomized to either receive a standard hip replacement with a highly cross-linked UHMWPE-X liner or a highly cross-linked vitamin-E supplemented UHMWPE-XE liner. The follow-up will be 15 years, with evaluation after 5, 10 and 15 years. The controlled randomized study has been designed to determine if Vitamin-E supplemented highly cross-linked polyethylene liners are superior to standard XLPE liners in cementless total hip arthroplasty. While several studies have been started to evaluate the influence of vitamin-E, most of them evaluate wear rates and functional results. The approach used for this multicenter study, to analyze the oxidation status of retrieved implants, should make it possible to directly evaluate the ageing process and development of the implant material itself over a time period of 15 years. PMID:25002933

Jäger, Marcus; van Wasen, Andrea; Warwas, Sebastian; Landgraeber, Stefan; Haversath, Marcel; Group, Vitas

2014-04-22

323

Computational modeling of hip replacement surgery: Total hip replacement vs. hip resurfacing  

Microsoft Academic Search

The motivation of the present work is the computational simulation of hip replacement surgery by means of a finite element approach based on open system thermodynamics. Its key feature is a non-constant material density, which is allowed to adapt with respect to changes in the mechanical loading environment. From a computational point of view, the density is treated as an

E. Kuhl; F. Balle

2005-01-01

324

Hip arthroscopy by the lateral approach.  

PubMed

Performing hip arthroscopy with the patient in the lateral decubitus position is advantageous in aiding in visualization of the hip joint, in maneuvering instruments in obese patients, and in facilitating entry to the hip joint in patients with spurs on the anterolateral aspect of the acetabulum. The patient is placed in the lateral decubitus position with the hip on which the surgery is being performed on the top. The leg is placed in traction and a well-padded perineal post is applied for countertraction. An image intensifier is placed around the hip to help direct the instruments into the hip joint. Traction is necessary to reach the depths of the hip joint. After traction is applied, two portals are made over the greater trochanter and one directly anterior to the greater trochanter. A capsulotomy is performed at each portal site to maintain the portals and to aid in maneuvering the arthroscope and instruments. Traction is released and the hip is flexed to allow visualization of the intracapsular area around the femoral neck. An additional, ancillary portal (made anterior and distal to the first direct anterior portal) may be required to reach the intracapsular portion around the femoral neck. A regular traction table requires adjustments of the perineal and traction posts to apply traction to the leg of a patient in the lateral decubitus position. Special traction devices make setup easier. The lateral approach to hip arthroscopy provides a safe and consistent method of entering, visualizing, and performing surgical procedures on the hip. PMID:16958467

Glick, James M

2006-01-01

325

Economic viability of geriatric hip fracture centers.  

PubMed

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

Clement, R Carter; Ahn, Jaimo; Mehta, Samir; Bernstein, Joseph

2013-12-01

326

Seven-year Results of a Tapered, Titanium, Hydroxyapatite-Coated Cementless Femoral Stem in Primary Total Hip Arthroplasty  

PubMed Central

Background Aseptic loosening of cemented hip prostheses is recognized as a long-term problem, and especially in males and younger patients. Much energy has been focused on developing new prostheses that are designed for cementless fixation. We evaluated the performance of and periprosthetic bone response to a tapered, titanium, hydroxyapatite (HA)-coated femoral hip prosthesis at a minimum of 7 years of follow-up after treatment with primary total hip arthroplasty. Methods Seventy-eight patients and 86 hips were included in the study. There were 35 men and 43 women; the mean age at the time of the operation was 59 years (range, 41 to 81 years). We used a tapered, titanium (Ti6Al4V), HA-coated femoral implant. We evaluated the patients at a minimum of 7 years of follow-up after treatment with primary total hip arthroplasty. Clinical evaluation was performed using the scoring system and the hip scores were assigned according to the level of pain, the functional status and the range of motion. The patients who refused to return, but who did forward X-rays for review after being contacted were questioned by phone about the functional status of their hip. Radiographic follow-up was performed at six weeks, at three, six and twelve months and yearly thereafter. All the available radiographs were collected and assessed for implant stability, subsidence, osseointegration, osteolysis, stress shielding and evidence of periprosthetic lucency. Results Eighty-six hips (78 patients) were available for review at follow-up of greater than 7 years. In 11 of the 86 cases, acetabular failure required revision of the acetabular component, but the femoral stem survived and it was available for long-term evaluation. The radiographs were obtained at 7-year follow-up for another 20 hips, but the patients would not come in for the 7-year clinical evaluation. Therefore, a phone interview was conducted to assess any change in the functional status at a minimum of 7 years. Conclusions The mechanical fixation of a tapered, titanium, HA-coated femoral implant was excellent in this study. This femoral design provided reliable osseointegration that was durable at a mean of 7 years follow-up. PMID:21119937

Cho, Jin-Ho; Choo, Suk-Kyu; Han, Kye-Young; Kim, Jung-Hoon; Oh, Hyoung-Keun

2010-01-01

327

SPACER: server for predicting allosteric communication and effects of regulation  

PubMed Central

The SPACER server provides an interactive framework for exploring allosteric communication in proteins with different sizes, degrees of oligomerization and function. SPACER uses recently developed theoretical concepts based on the thermodynamic view of allostery. It proposes easily tractable and meaningful measures that allow users to analyze the effect of ligand binding on the intrinsic protein dynamics. The server shows potential allosteric sites and allows users to explore communication between the regulatory and functional sites. It is possible to explore, for instance, potential effector binding sites in a given structure as targets for allosteric drugs. As input, the server only requires a single structure. The server is freely available at http://allostery.bii.a-star.edu.sg/. PMID:23737445

Goncearenco, Alexander; Mitternacht, Simon; Yong, Taipang; Eisenhaber, Birgit; Eisenhaber, Frank; Berezovsky, Igor N.

2013-01-01

328

Flows through sequential orifices with heated spacer reservoirs  

NASA Technical Reports Server (NTRS)

Flow rates and pressure thermal profiles for two phase choked flows of fluid nitrogen were studied theoretically and experimentally in a four sequential orifice configuration. Both theory and experimental evidence demonstrate that heat addition in the first spacer-reservoir adjacent to the inlet orifice is most effective in reducing the flow rate and that heat addition in the last spacer-reservoir is least effective. The flows are choked at the exit orifice for large spacings and at the inlet orifice for small spacings. The moderate addition of heat available for this experiment did not materially alter this result for large spacings; however, significant heat addition for the small spacings tended to shift the choke point to the exit orifice. Nitrogen is used as the working fluid over a range of states from liquid to gas with a reduced inlet stagnation pressure range to P sub r, o = 2.

Hendricks, R. C.; Stetz, T. T.

1982-01-01

329

SPACER: Server for predicting allosteric communication and effects of regulation.  

PubMed

The SPACER server provides an interactive framework for exploring allosteric communication in proteins with different sizes, degrees of oligomerization and function. SPACER uses recently developed theoretical concepts based on the thermodynamic view of allostery. It proposes easily tractable and meaningful measures that allow users to analyze the effect of ligand binding on the intrinsic protein dynamics. The server shows potential allosteric sites and allows users to explore communication between the regulatory and functional sites. It is possible to explore, for instance, potential effector binding sites in a given structure as targets for allosteric drugs. As input, the server only requires a single structure. The server is freely available at http://allostery.bii.a-star.edu.sg/. PMID:23737445

Goncearenco, Alexander; Mitternacht, Simon; Yong, Taipang; Eisenhaber, Birgit; Eisenhaber, Frank; Berezovsky, Igor N

2013-07-01

330

Fretting corrosion accelerates crevice corrosion of modular hip tapers.  

PubMed

The use of multiple-component systems in orthopedic surgery gives the surgeon increased flexibility in choosing the optimal implant, but introduces the possibility of interfacial corrosion. Such corrosion could limit the longevity of prostheses due either to tissue reactions to corrosion products, or to device failure. The incidence and nature of corrosion of modular total hips was evaluated in a consecutive series of 79 retrieved implants from University Hospitals of Cleveland. Surfaces were examined with stereo- and scanning electron microscopy. Several laboratory studies were undertaken to examine mechanisms that might contribute to the initiation of corrosion. The first set of experiments investigated the effect of head neck extension; the second study looked at the effect of material combinations on fretting corrosion and crevice corrosion. Analysis of retrieved implants demonstrated that fretting corrosion played a major role in the initiation of interface corrosion, and that a correlation existed between corrosion and length of neck extensions. Laboratory studies showed that longer head neck extensions may be more susceptible to fretting corrosion because of an instability at the interface. Short-term mixed-metal corrosion studies demonstrated that the coupling of cobalt and titanium alloys did not render the interface more susceptible to corrosion. It is hypothesized that fretting corrosion contributes to the initiation of modular interface corrosion, and that the problem can be reduced by design changes that increase the stability of the interface. PMID:7703534

Brown, S A; Flemming, C A; Kawalec, J S; Placko, H E; Vassaux, C; Merritt, K; Payer, J H; Kraay, M J

1995-01-01

331

Improving electricity production in tubular microbial fuel cells through optimizing the anolyte flow with spiral spacers.  

PubMed

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

Zhang, Fei; Ge, Zheng; Grimaud, Julien; Hurst, Jim; He, Zhen

2013-04-01

332

Hydrogels Containing Peptide or Aminosugar Sequences Implanted into the Rat Brain: Influence on Cellular Migration and Axonal Growth  

Microsoft Academic Search

Biocompatible polymer matrices for implantation into lesion sites in the brain were synthesized by incorporating peptide or aminosugar sequences intoN-(2-hydroxypropyl)methacrylamide (HPMA) hydrogels. RGD peptide sequences were chemically linked to the hydrogel backbone via a glycylglycine spacer; aminosugars were glucosamine (NHGlc) orN-acetylglucosamine residues. Unmodified or sequence containing HPMA hydrogels were implanted into the lesioned optic tract or cerebral cortex of juvenile

Giles W. Plant; Stèphane Woerly; Alan R. Harvey

1997-01-01

333

Results of Birmingham hip resurfacing at 12 to 15 years: a single-surgeon series.  

PubMed

We report a 12- to 15-year implant survival assessment of a prospective single-surgeon series of Birmingham Hip Resurfacings (BHRs). The earliest 1000 consecutive BHRs including 288 women (335 hips) and 598 men (665 hips) of all ages and diagnoses with no exclusions were prospectively followed-up with postal questionnaires, of whom the first 402 BHRs (350 patients) also had clinical and radiological review. Mean follow-up was 13.7 years (12.3 to 15.3). In total, 59 patients (68 hips) died 0.7 to 12.6 years following surgery from unrelated causes. There were 38 revisions, 0.1 to 13.9 years (median 8.7) following operation, including 17 femoral failures (1.7%) and seven each of infections, soft-tissue reactions and other causes. With revision for any reason as the end-point Kaplan-Meier survival analysis showed 97.4% (95% confidence interval (CI) 96.9 to 97.9) and 95.8% (95% CI 95.1 to 96.5) survival at ten and 15 years, respectively. Radiological assessment showed 11 (3.5%) femoral and 13 (4.1%) acetabular radiolucencies which were not deemed failures and one radiological femoral failure (0.3%). Our study shows that the performance of the BHR continues to be good at 12- to 15-year follow-up. Men have better implant survival (98.0%; 95% CI 97.4 to 98.6) at 15 years than women (91.5%; 95% CI 89.8 to 93.2), and women < 60 years (90.5%; 95% CI 88.3 to 92.7) fare worse than others. Hip dysplasia and osteonecrosis are risk factors for failure. Patients under 50 years with osteoarthritis fare best (99.4%; 95% CI 98.8 to 100 survival at 15 years), with no failures in men in this group. PMID:25274912

Daniel, J; Pradhan, C; Ziaee, H; Pynsent, P B; McMinn, D J W

2014-10-01

334

Assessment of modified gold surfaced titanium implants on skeletal fixation.  

PubMed

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-?B-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

Zainali, Kasra; Danscher, Gorm; Jakobsen, Thomas; Baas, Jorgen; Møller, Per; Bechtold, Joan E; Soballe, Kjeld

2013-01-01

335

Changes in implant choice and surgical technique for hemiarthroplasty  

PubMed Central

Background and purpose Treatment of displaced femoral neck fractures in Sweden has shifted towards more arthroplasties, especially hemiarthroplasties. We describe the hemiarthroplasty population in Sweden 2005 through 2009. Methods Since 2005, the Swedish Hip Arthroplasty Register has registered hemiarthroplasties on a national basis. We assessed hemiarthroplasty procedures in the Register 2005–2009 regarding patient details, implants, and surgical techniques. Completeness of recordings was calculated compared to the Swedish National Patient Register. Results Completeness increased from 89% to 96% during the study period. 21,346 hemiarthroplasty procedures were assessed. The relative number of patients with femoral neck fracture as diagnosis increased from 91% to 94%; the proportion of men increased from 27% to 30%. The median age increased from 83 to 84 years in men and from 84 to 85 years in women. Patients classified as having evident cognitive impairment increased from 19% to 22%. More men than women were ASA 4. The proportion of monoblock-type implants (Austin-Moore and Thompson) decreased from 18% to 0.9%. Modular implants increased generally, but in 2009 bipolar implants decreased in favor of unipolar implants. Lubinus and Exeter stems, and Mega Caput and Vario Cup implant heads were most common. The use of uncemented implants decreased from 10% to 3%. Use of the anterolateral approach increased from 47% to 56%. Interpretation Important changes in surgical technique and implant choice occurred during the observation period. We interpret these changes as being reflections of the continuing effort by Swedish orthopedic surgeons to improve the quality of treatment, because the changes are consistent with recent findings in the Swedish Hip Arthroplasty Register and in other scientific studies. PMID:22112151

2012-01-01

336

Structural design feasibility study of Space Station long spacer truss  

NASA Technical Reports Server (NTRS)

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.

Armand, Sasan C.; Funk, Gregory P.; Dohogne, Caroline A.

1994-01-01

337

Biomechanics of Lateral Interbody Spacers: Going Wider for Going Stiffer  

PubMed Central

This study investigates the biomechanical stability of a large interbody spacer inserted by a lateral approach and compares the biomechanical differences with the more conventional transforaminal interbody fusion (TLIF), with and without supplemental pedicle screw (PS) fixation. Twenty-four L2-L3 functional spinal units (FSUs) were tested with three interbody cage options: (i) 18?mm XLIF cage, (ii) 26?mm XLIF cage, and (iii) 11?mm TLIF cage. Each spacer was tested without supplemental fixation, and with unilateral and bilateral PS fixation. Specimens were subjected to multidirectional nondestructive flexibility tests to 7.5?N·m. The range of motion (ROM) differences were first examined within the same group (per cage) using repeated-measures ANOVA, and then compared between cage groups. The 26?mm XLIF cage provided greater stability than the 18?mm XLIF cage with unilateral PS and 11?mm TLIF cage with bilateral PS. The 18?mm XLIF cage with unilateral PS provided greater stability than the 11?mm TLIF cage with bilateral PS. This study suggests that wider lateral spacers are biomechanically stable and offer the option to be used with less or even no supplemental fixation for interbody lumbar fusion. PMID:23213284

Pimenta, Luiz; Turner, Alexander W. L.; Dooley, Zachary A.; Parikh, Rachit D.; Peterson, Mark D.

2012-01-01

338

Low in vitro third-body wear on total hip prostheses induced by calcium sulphate used for local antibiotic therapy.  

PubMed

In case of implant associated infection, implant preservation is associated with high failure rates. Therefore, a removal or exchange of the implant is most often mandatory for treatment success. Alternatively, under certain conditions, local antibiotic delivery can be applied - preserving the implant, using for example calcium sulphate as a resorbable carrier. In this work, third-body wear on total hip prostheses caused by calcium sulphate particles was tested in a hip simulator. Inlays made of ultra-high-molecular-weight polyethylene (UHMWPE) and cross-linked polyethylene (XLPE) against 28 mm CoCrMo heads and 36 mm alumina pairings were tested in triplicate, both with and without calcium sulphate particles in the test liquid. Neither the alumina articulations nor the CoCrMo heads were affected by the calcium sulphate particles since calcium sulphate is a relatively soft material. The polyethylene inlays showed 39-89 % higher wear during exposure compared to references, but wear returned to normal when no more particles were added. Thus, calcium sulphate might be used as antibiotic carrier even in the presence of total hip prostheses without fearing excessive third-body wear. PMID:25340804

Heuberger, R; Wahl, P; Krieg, J; Gautier, E

2014-01-01

339

Total hip replacement in congenital high hip dislocation following iliofemoral monotube distraction  

Microsoft Academic Search

The aim of this study was to prospectively evaluate our single-centre one- and five-year results of anatomically correct cementless\\u000a total hip arthroplasty in unilateral and bilateral Crowe type IV high hip dislocations in ten hips following iliofemoral monotube\\u000a soft tissue distraction. Six consecutive patients (five females and one male) with unilateral and two female patients with\\u000a bilateral high hip dislocation

Johannes Holinka; Martin Pfeiffer; Jochen G. Hofstaetter; Richard Lass; Rainer I. Kotz; Alexander Giurea

2011-01-01

340

Alumina-on-alumina total hip replacement for femoral neck fracture in healthy patients  

PubMed Central

Background Total hip replacement is considered the best option for treatment of displaced intracapsular fractures of the femoral neck (FFN). The size of the femoral head is an important factor that influences the outcome of a total hip arthroplasty (THA): implants with a 28 mm femoral head are more prone to dislocate than implants with a 32 mm head. Obviously, a large head coupled to a polyethylene inlay can lead to more wear, osteolysis and failure of the implant. Ceramic induces less friction and minimal wear even with larger heads. Methods A total of 35 THAs were performed for displaced intracapsular FFN, using a 32 mm alumina-alumina coupling. Results At a mean follow-up of 80 months, 33 have been clinically and radiologically reviewed. None of the implants needed revision for any reason, none of the cups were considered to have failed, no dislocations nor breakage of the ceramic components were recorded. One anatomic cementless stem was radiologically loose. Conclusions On the basis of our experience, we suggest that ceramic-on-ceramic coupling offers minimal friction and wear even with large heads. PMID:21284879

2011-01-01

341

Routine complete capsular closure during hip arthroscopy.  

PubMed

The utility of hip arthroscopy has recently progressed beyond diagnostic to therapeutic purposes addressing central and peripheral compartment pathologies. Capsulotomy provides freedom of visualization and instrumentation. The contribution to hip stability of both dynamic and static hip structures is not fully understood. However, both basic science biomechanical and clinical outcome studies have exhibited a relevant role of the capsule in hip stability. Though rare, iatrogenic post-arthroscopy subluxation and dislocation have been reported. Therefore many surgeons have cautioned against aggressive capsulotomy or capsulectomy without repair, because of the potential for precipitation of iatrogenic hip instability. We typically perform a "T" capsulotomy and recommend complete capsular closure in conjunction with labral repair and osseous femoral and acetabular treatment. A safe, efficient, and effective method to accomplish complete capsular closure is presented to reduce iatrogenic postoperative hip instability. PMID:23875156

Harris, Joshua D; Slikker, William; Gupta, Anil K; McCormick, Frank M; Nho, Shane J

2013-05-01

342

Routine Complete Capsular Closure During Hip Arthroscopy  

PubMed Central

The utility of hip arthroscopy has recently progressed beyond diagnostic to therapeutic purposes addressing central and peripheral compartment pathologies. Capsulotomy provides freedom of visualization and instrumentation. The contribution to hip stability of both dynamic and static hip structures is not fully understood. However, both basic science biomechanical and clinical outcome studies have exhibited a relevant role of the capsule in hip stability. Though rare, iatrogenic post-arthroscopy subluxation and dislocation have been reported. Therefore many surgeons have cautioned against aggressive capsulotomy or capsulectomy without repair, because of the potential for precipitation of iatrogenic hip instability. We typically perform a “T” capsulotomy and recommend complete capsular closure in conjunction with labral repair and osseous femoral and acetabular treatment. A safe, efficient, and effective method to accomplish complete capsular closure is presented to reduce iatrogenic postoperative hip instability. PMID:23875156

Harris, Joshua D.; Slikker, William; Gupta, Anil K.; McCormick, Frank M.; Nho, Shane J.

2013-01-01

343

Posterior Hip Pain in an Athletic Population  

PubMed Central

Context: Posterior hip pain is a relatively uncommon but increasingly recognized complaint in the orthopaedic community. Patient complaints and presentations are often vague or nonspecific, making diagnosis and subsequent treatment decisions difficult. The purposes of this article are to review the anatomy and pathophysiology related to posterior hip pain in the athletic patient population. Evidence Acquisition: Data were collected through a thorough review of the literature via a MEDLINE search of all relevant articles between 1980 and 2010. Results: Many patients who complain of posterior hip pain actually have pain referred from another part of the body—notably, the lumbar spine or sacroiliac joint. Treatment options for posterior hip pain are typically nonoperative; however, surgery is warranted in some cases. Conclusions: Recent advancements in the understanding of hip anatomy, pathophysiology, and treatment options have enabled physicians to better diagnosis athletic hip injuries and select patients for appropriate treatment. PMID:23015944

Frank, Rachel M.; Slabaugh, Mark A.; Grumet, Robert C.; Virkus, Walter W.; Bush-Joseph, Charles A.; Nho, Shane J.

2010-01-01

344

Decaborane implantation with the medium current implanter  

NASA Astrophysics Data System (ADS)

A decaborane implantation system has been developed. The maximum beam current achieved at a wafer is 30 ?A at 5 keV with the divergence less than 0.4°, which corresponds to the equivalent 500 eV-300 ?A boron monomer implantation without an energy contamination. As-implanted secondary ion mass spectroscopy (SIMS) profile of the decaborane implanted at the equivalent energy 500 eV shows the steeper and shallower profile than that of the boron implanted. The result of Rs- Xj proves the higher activation with shallower junction depth. These advantages possibly arise from the self-amorphization layer by the decaborane implantation.

Hamamoto, Nariaki; Umisedo, Sei; Nagayama, Tsutomu; Tanjyo, Masayasu; Sakai, Shigeki; Nagai, Nobuo; Aoyama, Takayuki; Nara, Yasuo

2005-08-01

345

Total Hip Arthroplasty Through a Minimal Posterior Approach Using Imageless Computer-Assisted Hip Navigation  

Microsoft Academic Search

With decreased exposure in a minimal posterior hip incision, navigation with computer assistance provides an alternative method to accurately place the components. This study compares the results of a series of 82 navigated total hips to a retrospective cohort of 50 hips done with conventional instruments. The surgical incision split the gluteus maximus but did not extend distally into the

Richard L. Wixson; Margot A. MacDonald

2005-01-01

346

A comprehensive review of hip labral tears  

Microsoft Academic Search

The hip labrum has many functions, including shock absorption, joint lubrication, pressure distribution, and aiding in stability,\\u000a with damage to the labrum associated with osteoarthritis. The etiology of labral tears includes trauma, femoroacetabular impingement\\u000a (FAI), capsular laxity\\/hip hypermobility, dysplasia, and degeneration. Labral tears present with anterior hip or groin pain,\\u000a and less commonly buttock pain. Frequently, there are also mechanical

Megan M. Groh; Joseph Herrera

2009-01-01

347

Alternative process for thin layer etching: Application to nitride spacer etching stopping on silicon germanium  

NASA Astrophysics Data System (ADS)

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.

Posseme, N.; Pollet, O.; Barnola, S.

2014-08-01

348

[Periarticular pathology of the hip].  

PubMed

The hip region is the seat of a rich and common periarticular pathology, with a variable involvement, depending of the location, and needs better knowledge. Anyway the clinical examination takes the major place in the diagnostic. Trochanteric bursitis and tendinitis are the more common clinical syndrome in that regional pathology. Local injections of corticosteroid are still the mean modality of the conservative treatment but are not sufficient to avoid recurrence or chronicity which may lead to tendon tears. A better knowledge of the physiopathology will lead to a better and early recovery. Apatite calcifications are not rare around the hip. Great trochanter is the first location, but the femoral insertion of the gluteus maximus and vastus lateralis on the linea aspera, the lateral side of the acetabulum and the ischial tuberosity are worth known. Iliopsoas bursitis, which has some analogy with the popliteal cyst, is often underrecognized, like ischial bursitis and tendinopathy. PMID:12001413

Bard, Hervé

2002-03-15

349

Systemic effects of implanted prostheses made of cobalt-chromium alloys  

Microsoft Academic Search

Systemic effects of Co-Cr alloy\\/polyethylene hip joint prostheses were investigated using instrumental neutron activation to determine the concentrations of up to 16 elements. First, in a prospective study whole blood and serum taken from 10 patients from 1 day before to 90 days after implantation were analyzed. Secondly, in a retrospective study whole blood and serum from 23 patients who

R. Michel; M. Nolte; M. Reich; F. Löer

1991-01-01

350

Life Estimation of Hip Joint Prosthesis  

NASA Astrophysics Data System (ADS)

Hip joint is one of the largest weight-bearing structures in the human body. In the event of a failure of the natural hip joint, it is replaced with an artificial hip joint, known as hip joint prosthesis. The design of hip joint prosthesis must be such so as to resist fatigue failure of hip joint stem as well as bone cement, and minimize wear caused by sliding present between its head and socket. In the present paper an attempt is made to consider both fatigue and wear effects simultaneously in estimating functional-life of the hip joint prosthesis. The finite element modeling of hip joint prosthesis using HyperMesh™ (version 9) has been reported. The static analysis (load due to the dead weight of the body) and dynamic analysis (load due to walking cycle) have been described. Fatigue life is estimated by using the S-N curve of individual materials. To account for progressive wear of hip joint prosthesis, Archard's wear law, modifications in socket geometry and dynamic analysis have been used in a sequential manner. Using such sequential programming reduction in peak stress has been observed with increase in wear. Finally life is estimated on the basis of socket wear.

Desai, C.; Hirani, H.; Chawla, A.

2014-11-01

351

Surgical hip dislocation: techniques for success.  

PubMed

Surgical hip dislocation (SHD) is a versatile approach used to address both intra-articular and extra-articular pathology around the hip joint in both pediatric and adult patients. It allows anterior dislocation of the femoral head for direct visualization of the hip joint while preserving femoral head vascularity and minimizing trauma to the abductor musculature. Previously described indications for SHD include femoroacetabular impingement, deformity resulting from Legg-Calve-Perthes disease, slipped capital femoral epiphysis, periarticular trauma, benign lesions of the hip joint, and osteochondral lesions. In this review, we will describe current surgical techniques, indications, and clinical outcomes for SHD. PMID:25207733

Ricciardi, Benjamin F; Sink, Ernest L

2014-01-01

352

Ceramic-on-ceramic total hip arthroplasty in patients younger than 55 years.  

PubMed

PURPOSE. To review the outcomes of 65 patients younger than 55 years who underwent uncemented total hip arthroplasty (THA) using third-generation ceramic-on-ceramic prostheses. METHODS. Medical records of 30 men and 35 women (80 hips) aged 18 to 55 (mean, 39) years who underwent uncemented THA using third-generation ceramic-onceramic prostheses by a single surgeon were reviewed. 61 THAs used the Reflection cup with the Synergy stem (n=49), Spectron stem (n=7), or Anthology stem (n=5), and 19 THAs used the Trident cup with the Secur-Fit stem. Outcomes were assessed based on the UCLA Activity Score and Harris Hip Score, as well as radiolucency around the implants, malposition, and subsidence on radiographs. Patients were asked about their satisfaction with current activity level (yes/no), activity limitation (no limitation, musculoskeletal limitation, psychological impediments and lack of motivation, and pain or disability of the operative hip), and change in occupational activity level (same or similar, more active, and less active or disability). RESULTS. The mean follow-up period was 54 (range, 24-110) months. Six patients were excluded from the analysis owing to prosthetic failure secondary to ceramic liner fracture after falling (n=2), acetabular component loosening (n=1), intolerable squeak (n=1), periprosthetic fracture (n=1), and instability (n=1). The mean UCLA Activity Score improved from 4.0 (range, 1-10) to 7.7 (range, 2-10) [p<0.001], and the mean Harris Hip Score improved from 52.8 (range, 25-69) to 91.0 (range, 38-100) [p<0.001]. No hip had evidence of subsidence, loosening, or osteolysis. 52 (80%) patients were satisfied with their activity level; 28 (43%) patients reported no activity limitation; and 57 (88%) patients kept the same or similar occupation. CONCLUSION. Ceramic-on-ceramic THA achieved acceptable clinical and radiographic outcomes. PMID:25550014

Shah, R P; Scolaro, J A; Componovo, R; Garino, J P; Lee, G C

2014-12-01

353

[Short-stemmed endoprostheses in total hip arthroplasty].  

PubMed

Short-stemmed endoprostheses in total hip arthroplasty are anchored exclusively in the metaphysis and the proximal part of the diaphysis. Therefore, they are much shorter than the classic standard stems. These implants are specially favourable in terms of eventual revision surgery, and also due to the fact that with close diaphyseal bone marrow spaces a sufficient proximal size dimensioning is possible. In this study, the best known short-stemmed systems in clinical use are introduced. Positive long-term results are so far available only with the Pipino and Mayo stems, short and partially medium-term experience with the remaining short stems (C.F.P.(R), Metha, PROXIMA, ESKA) are--with the available learning curve--encouraging. Despite the call for sufficient experience and scientific evaluation, short-stemmed endoprostheses already represent a valuable alternative in endoprosthetics for younger patients. PMID:17377765

Gulow, J; Scholz, R; Freiherr von Salis-Soglio, G

2007-04-01

354

Do revision total hip augments provide appropriate modularity?  

PubMed Central

Background Porous metal acetabular augments have become widely used to fill bony defects in patients undergoing revision total hip arthroplasty. The objective of this study was to determine whether the currently offered size range of the augments is appropriate for surgical needs. Methods We reviewed the cases of all patients at 1 centre with a porous revision shell, and when an augment was used we recorded the patient and implant characteristics. Results We reviewed the cases of 281 patients, and augments were used in 24. Augment diameter was skewed toward the small end (p < 0.001), although thickness was not (p = 0.05); 21 of 24 augments were those with the smallest 3 diameters and thicknesses. Conclusion Given the sizes used, the full range of inventory provided by the manufacturer may be unnecessary, as surgeons will likely attempt a larger shell before a larger augment. PMID:25621911

Teeter, Matthew G.; Naudie, Douglas D. R.; Howard, James L.; McCalden, Richard W.; MacDonald, Steven J.

2015-01-01

355

Reproducible fixation with a tapered, fluted, modular, titanium stem in revision hip arthroplasty at 8-15 years follow-up.  

PubMed

The use of tapered, fluted, modular, distally fixing stems has increased in femoral revision surgery. The goal of this retrospective study was to assess mid-term to long-term outcomes of this implant. Seventy-one hips in 70 patients with a mean age of 69 years were followed for an average of 10 years. Preoperative HHS averaged 50 and improved to 87 postoperatively. Seventy-nine percent hips had Paprosky type 3A or more bone-loss. All stems osseointegrated distally (100%). Two hips subsided >5mm but achieved secondary stability. Sixty-eight percent hips had evidence of bony reconstitution and 21% demonstrated diaphyseal stress-shielding. One stem fractured near its modular junction and was revised with a mechanical failure rate of 1.4%. Distal fixation and clinical improvement were reproducibly achieved with this stem design. PMID:24994705

Rodriguez, Jose A; Deshmukh, Ajit J; Robinson, Jonathan; Cornell, Charles N; Rasquinha, Vijay J; Ranawat, Amar S; Ranawat, Chitranjan S

2014-09-01

356

The use of megavoltage cone-beam CT to complement CT for target definition in pelvic radiotherapy in the presence of hip replacement.  

PubMed

In Europe and the USA combined, over half a million people had a hip joint replaced in 2005, contributing to the increasing number of radiotherapy patients with metallic hip prostheses. The treatment plan for external beam radiation therapy is based on the delineation of the anatomy in the planning CT scan. When implanted objects of high atomic number (Z) material are present, however, severe image artefacts are generated in conventional CT, strongly hindering the ability to delineate some organs. This is particularly the case for the planning of prostate patients with hip prostheses. This short communication presents the use of a new imaging modality, megavoltage cone-beam CT, to complement the regular CT for target definition of prostate cancer treatment of patients with hip replacements. PMID:16916807

Aubin, M; Morin, O; Chen, J; Gillis, A; Pickett, B; Aubry, J F; Akazawa, C; Speight, J; Roach, M; Pouliot, J

2006-11-01

357

Surgeons' knowledge about the costs of orthopaedic implants.  

PubMed

PURPOSE. To investigate consultant surgeons' knowledge about the costs of implants for various joint surgeries. METHODS. Questionnaires were distributed to consultant orthopaedic surgeons at 2 hospitals. Respondents were asked to estimate the implant costs of any brand for low-demand and high-demand total hip replacement (THR), total knee replacement (TKR), uni-compartmental knee replacement, arthroscopy shaver blade, total anterior cruciate ligament (ACL) fixation, and meniscal repair. The actual cost of each implant was obtained from the manufacturer. RESULTS. 16 consultant surgeons completed the questionnaires. The respective mean estimated and actual costs for a low-demand THR implant were £1714 (range, £600-3000) and £1448 (range, £985- 2335), with an overestimation of 18.4%. The respective costs for a high-demand THR implant were £2172 (range, £600-6000) and £1737 (range, £1192-2335), with an overestimation of 25%. The respective costs for a TKR implant were £1550 (range, £600-6000) and £1316 (range, £995-1535), with an overestimation of 17.8%. The respective costs for a uni-compartmental knee replacement implant were £1040 (range, £600-2000) and £1296 (range, £698-1470), with an underestimation of 19.7%. The respective costs for an arthroscopy shaver blade were £110 (range, £75-150) and £94 (range, £80-100), with an overestimation of 16.6%. The respective costs for a total ACL fixation implant were £246 (range, £80-500) and £306 (range, £272-335), with an underestimation of 19.4%. The respective costs for a meniscal repair implant were £153 (range, £50-250) and £242 (range, £170-260), with an underestimation of 37%. CONCLUSION. The knowledge among consultant orthopaedic surgeons about implant costs was poor. To reduce implant costs, cooperation between surgeons and hospital managers and measures to increase surgeons' awareness about cost-reduction programmes are needed. PMID:25163960

Rohman, Lebur; Hadi, Saifullah; Whitwell, George

2014-08-01

358

Development of a carbon-carbon hip prosthesis.  

PubMed

This article deals with the use of carbon-fiber-reinforced-carbon materials for the manufacture of hip prosthesis stems. It considers the manufacturing process of carbon-carbon (C-C) composites made of carbon fibers infiltrated either with dense pyrolytic carbon or silicon carbide (SiC) through chemical vapor infiltration. The chemicophysical properties of these composites are examined according to their structures. The long-term response (2 years) of cortical bone to various types of carbon-carbon was evaluated mainly for bone contact and ingrowth. Carbon-carbon coated with calcium phosphate was found to speed up the bone formation as compared to pyrolytic carbon or SiC coatings. The low modulus of elasticity of the C-C materials could be responsible for quicker bone contact as compared to a much stiffer material like sintered aluminum oxide. The biomechanical performance of C-C hip stems was assessed through (a) implantations into cadaver femurs, (b) fatigue testing, and (c) finite element analysis. These tests showed: (a) a better stress transfer as compared to a metal prosthesis having the same design, (b) no fatigue damage, (c) a computerized stem stress distribution in accordance with the fractures obtained during static mechanical testing. PMID:3624286

Christel, P; Meunier, A; Leclercq, S; Bouquet, P; Buttazzoni, B

1987-08-01

359

[Gait analysis after minimally invasive total hip arthroplasty].  

PubMed

Upon implantation of a hip prosthesis by total hip arthroplasty (THA), clinical criteria are not always sufficient for an objective assessment of the functional outcome. Thus, functional improvement of gait behavior was comparatively validated by instrumented 3D gait analysis for a current, minimally invasive surgical approach (MIS; anterolateral approach) and a conventional, transgluteal approach (KONV). In selected cases, disturbed motion sequences were registered by measuring the muscle activity via high-resolution, monopolar surface electromyography (S-EMG) above the operation area. Despite continuous and significant improvement of practically all analyzed kinematic and kinetic gait parameters for both surgical approaches already after 5 weeks but in particular after 6 and 12 months, no significant differences were detected between the 2 procedures for any parameter or time point. The S-EMG demonstrated non-physiological muscle activation on the operated, but also on the non-operated side, even at 6 months after surgery. Advantages of the MIS approach thus seem primarily restricted to early, post-operative results, such as more rapid pain reduction and rehabilitation. PMID:22552542

Sander, K; Layher, F; Anders, C; Roth, A; Babisch, J; Scholle, H-C; Kinne, R W

2012-05-01

360

Model-based cone-beam CT reconstruction for image-guided minimally invasive treatment of hip osteolysis  

NASA Astrophysics Data System (ADS)

Purpose: Accurate assessment of the size and location of osteolytic regions is essential in minimally invasive hip revision surgery. Moreover, image-guided robotic intervention for osteolysis treatment requires precise localization of implant components. However, high density metallic implants in proximity to the hip make assessment by either 2D or 3D x-ray imaging difficult. This paper details the initial implementation and evaluation of an advanced model-based conebeam CT (CBCT) reconstruction algorithm to improve guidance and assessment of hip osteolysis treatment. Method: A model-based reconstruction approach called Known Component Reconstruction (KCR) was employed to obtain high-quality reconstruction of regions neighboring metallic implants. KCR incorporates knowledge about the implant shape and material to precisely reconstruct surrounding anatomy while simultaneously estimating implant position. A simulation study involving a phantom generated from a CBCT scan of a cadaveric hip was performed. Registration accuracy in KCR iterations was evaluated as translational and rotational error from the true registration. Improvement in image quality was evaluated using normalized cross correlation (NCC) in two regions of interest (ROIs) about the femoral and acetabular components. Result: The study showed significant improvement in image quality over conventional filtered backprojection (FBP) and penalized-likelihood (PL) reconstruction. The NCC in the two ROIs improved from 0.74 and 0.81 (FBP) to 0.98 and 0.86 (PL) and >0.99 for KCR. The registration error was 0.01 mm in translation (0.02° in rotation) for the acetabular component and 0.01 mm (0.01° rotation) for the femoral component. Conclusions: Application of KCR to imaging hip osteolysis in the presence of the implant offers a promising step toward quantitative assessment in minimally invasive image-guided osteolysis treatment. The method improves image quality (metal artifact reduction), yields a precise registration estimate of the implant, and offers a means for reducing radiation dose in intraoperative CBCT.

Otake, Yoshito; Stayman, J. W.; Zbijewski, W.; Murphy, R. J.; Kutzer, M. D.; Taylor, R. H.; Siewerdsen, J. H.; Armand, M.

2013-03-01

361

Decaborane implantation with the medium current implanter  

Microsoft Academic Search

A decaborane implantation system has been developed. The maximum beam current achieved at a wafer is 30?A at 5keV with the divergence less than 0.4°, which corresponds to the equivalent 500eV–300?A boron monomer implantation without an energy contamination. As-implanted secondary ion mass spectroscopy (SIMS) profile of the decaborane implanted at the equivalent energy 500eV shows the steeper and shallower profile

Nariaki Hamamoto; Sei Umisedo; Tsutomu Nagayama; Masayasu Tanjyo; Shigeki Sakai; Nobuo Nagai; Takayuki Aoyama; Yasuo Nara

2005-01-01

362

Early complications of anterior supine intermuscular total hip arthroplasty.  

PubMed

Anterior supine intermuscular total hip arthroplasty (THA) performed on a fracture table has been increasingly used for primary THA. Accurate cup placement, low incidence of dislocation, shorter hospital stay, and faster return of function are potential benefits of the technique. However, a high complication rate, particularly during a surgeon's learning curve, has been reported. A retrospective analysis of 61 consecutive anterior supine intermuscular primary THAs with at least 6-month follow-up was performed. All procedures were performed using the anterior supine intermuscular approach with cementless implants under fluoroscopic guidance on a fracture table. Prospectively collected data were retrospectively reviewed to evaluate the early complication rate and radiographic accuracy of implant placement. Five (8.2%) intraoperative complications were observed: including 3 trochanteric fractures and 2 calcar fractures, 4 of which required cable fixation during the index procedure. One nondisplaced trochanteric fracture was treated conservatively. One patient sustained an injury of the lateral femoral cutaneous nerve. Postoperative complications included 1 anterior dislocation, 1 infected superficial hematoma, 1 stem subsidence, and 1 loose stem, with the latter 2 presenting as increasing thigh pain postoperatively and requiring stem revision. The overall complication rate was 16.4% (10/61). Overall, 3 patients (4 hips; 6.5%) required reoperation. No femoral or sciatic nerve injuries occurred, and no patient was diagnosed with venous thromboembolism. All intraoperative fractures occurred during the first 32 cases, and none during the last 29 cases. A potentially high incidence of complications with the anterior supine intermuscular THA exists during a surgeon's learning curve in an academic setting. PMID:23464946

Yi, Chengla; Agudelo, Juan F; Dayton, Michael R; Morgan, Steven J

2013-03-01

363

Tribolayer Formation in a Metal-on-Metal (MoM) Hip Joint: An Electrochemical Investigation  

PubMed Central

The demand for total hip replacement (THR) surgery is increasing in the younger population due to faster rehabilitation and more complete restoration of function. Up to 2009, metal-on-metal (MoM) hip joint bearings were a popular choice due to their design flexibility, post-operative stability and relatively low wear rates. The main wear mechanisms that occur along the bearing surface of MoM joints are tribochemical reactions that deposit a mixture of wear debris, metal ions and organic matrix of decomposed proteins known as a tribolayer. No in-depth electrochemical studies have been reported on the structure and characteristics of this tribolayer or about the parameters involved in its formation. In this study, we conducted an electrochemical investigation of different surfaces (bulk-like: control, nano-crystalline: new implant and tribolayer surface: retrieved implant) made out of two commonly used hip CoCrMo alloys (high-carbon and low-carbon). As per ASTM standard, cyclic polarization tests and electrochemical impedance spectroscopy tests were conducted. The results obtained from electrochemical parameters for different surfaces clearly indicated a reduction in corrosion for the tribolayer surface (Icorr: 0.76 ?A/cm2). Further, polarization resistance (Rp:2.39±0.60M?/cm2) and capacitance (Cdl:15.20±0.75 ?F/cm2) indicated variation in corrosion kinetics for the tribolayer surface, that attributed to its structure and stability in a simulated body environment. PMID:24099949

Mathew, MT; Nagelli, C; Pourzal, R; Fischer, A; Laurent, MP; Jacobs, JJ; Wimmer, MA

2013-01-01

364

Acute delayed infection: increased risk in failed metal on metal total hip arthroplasty.  

PubMed

Adverse local tissue reactions occurring in metal-on-metal total hip arthroplasty (MoM THA) could potentially lead to secondary failure modes such as dislocation or infection. The authors report a series of 124 patients treated with MoM hip arthroplasty between 2006 and 2010 with a minimum follow-up of 3 years. Eight hips presented with acute delayed or late periprosthetic joint infection (PJI) (defined as an infection occurring after 3 months in an otherwise well functioning implant). The rate of infection observed was higher than expected, almost 4 times higher (5.6%) compared to previous historical cohorts from our institution (1.3%). This high risk of infection in patients with DePuy ASR implants requires further study but we theorize that the increased prevalence of infection could be due to a combination of particulate debris, molecular (rather than particulate) effects of Co and Cr ions on soft tissues, and/or products of corrosion that may change the local environment predisposing to infection. PMID:24851788

Prieto, Hernan A; Berbari, Elie F; Sierra, Rafael J

2014-09-01

365

Variations in the trunnion surface topography between different commercially available hip replacement stems.  

PubMed

Modular hip implants allows for the adjustment of leg length, offset, and the ability to remove the head for acetabular exposure during primary and revision surgery. The design of the Morse taper facilitates the intimate contact of the conical trunnion of the femoral stem (male component), with the conical bore of the femoral head (female component). Orthopaedic trunnion tapers are not standardized and vary in length, taper angle, and base dimension. Variations in the design and surface characteristics of the trunnion, will directly reflect on the interface at the taper junction and can influence the likelihood of subsequent wear, corrosion and longevity of the implant. The effect of surface topography of trunnions on commercially available hip stems has not yet been considered as a possible contributing factor in the corrosion observed at taper junctions. In this study we analyzed the surface topography and surface roughness of randomly selected commercially available femoral hip stem trunnions to obtain a greater insight into their surface characteristics. PMID:25319315

Munir, Selin; Walter, William L; Walsh, William Robert

2015-01-01

366

The hip-spine connection: understanding its importance in the treatment of hip pathology.  

PubMed

EDUCATIONAL OBJECTIVES As a result of reading this article, physicians should be able to: 1. Discuss the kinematic relationship between the hip and lumbar spine. 2. Explain the innervation of the hip and lumbar spine and how they relate to one another. 3. Recognize the effect of hip disease on the lumbar spine in an athletic population, prior to the onset of degenerative changes. 4. Describe an algorithm for diagnosis and treatment of patients who present with concomitant hip and lumbar spine pain. The hip and lumbar spine are closely related and can create similar patterns of pain and dysfunction. Diagnosis and treatment of hip and spine-related conditions can be challenging due to symptom overlap. Successful evaluation and treatment of hip and lumbar spine conditions requires a thorough understanding the hip-spine connection. Historically the hip-spine connection has been considered in the context of arthrosis; however, the hip-spine connection also needs to be considered in a younger athletic population. The purpose of this review is to describe the hip-spine connection, discuss the clinical implications of this connection, and offer an approach to diagnosis and treatment. [Orthopedics. 2015; 38(1):49-55.]. PMID:25611411

Redmond, John M; Gupta, Asheesh; Nasser, Rima; Domb, Benjamin G

2015-01-01

367

Joint issues – conflicts of interest, the ASR hip and suggestions for managing surgical conflicts of interest  

PubMed Central

Background Financial and nonfinancial conflicts of interest in medicine and surgery are troubling because they have the capacity to skew decision making in ways that might be detrimental to patient care and well-being. The recent case of the Articular Surface Replacement (ASR) hip provides a vivid illustration of the harmful effects of conflicts of interest in surgery. Discussion We identify financial and nonfinancial conflicts of interest experienced by surgeons, hospitals and regulators in the ASR case. These conflicts may have impacted surgical advice, decision-making and evidence gathering with respect to the ASR prosthesis, and contributed to the significant harms experienced by patients in whom the hip was implanted. Drawing on this case we explore shortcomings in the standard responses to conflicts of interest – disclosure and recusal. We argue disclosure is necessary but by no means sufficient to address conflicts of interest. Using the concept of recusal we develop remedies including second opinions and third party consent which may be effective in mitigating conflicts, but their implementation introduces new challenges. Summary Deployment of the ASR hip is a case of surgical innovation gone wrong. As we show, there were multiple conflicts of interest involved in the introduction of the ASR hip into practice and subsequent attempts to gloss over the mounting body of evidence about its lack of safety and effectiveness. Conflicts of interest in surgery are often not well managed. We suggest strategies in this paper which can minimise the conflicts of interest associated with surgical innovation. PMID:25128372

2014-01-01

368

Total hip replacement as primary treatment of unstable intertrochanteric fractures in elderly patients  

PubMed Central

Fifty-three patients with A2.2 and A2.3 intertrochanteric fracture according to the Muller classification were treated with total hip replacement between April 2000 and February 2004. The average age of the patients was 77 years. Average follow-up period was 3.7 years. We studied postoperative complications, mortality rate, functional outcome using the Harris hip score, time to return to normal activities, and radiographic evidence of healing. Two patients died on the third and fifth postoperative days. Seven more patients died within one year. The Harris hip score at one month was 66 ± 7 (mean ± standard deviation); at three months 72 ± 6; at one year 74 ± 5; at three years 76 ± 6 and in the 27 patients who completed five year follow-up it was 76 ± 8. Mobilisation and weight-bearing was started immediately in the postoperative period. Average time taken to return to normal daily activities was 28 days (range 24–33). No loosening or infection of the implants was observed. Total hip arthroplasty is a valid treatment option for mobile and mentally healthy elderly patients with intertrochanteric fractures. This procedure offers quick recovery with little risk of mechanical failure, avoids the risks associated with internal fixation and enables the patient to maintain a good level of function immediately after surgery. PMID:19517109

Sidhu, Amarjit Singh; Singh, Arun Pal; Singh, Sukhraj

2009-01-01

369

Hip Joint Replacement Using Monofilament Polypropylene Surgical Mesh: An Animal Model  

PubMed Central

Hip joint dysplasia is a deformation of the articular elements (pelvic acetabulum, head of the femur, and/or ligament of the head of the femur) leading to laxity of the hip components and dislocation of the femoral head from the pelvic acetabulum. Diagnosis is based on symptoms observed during clinical and radiological examinations. There are two treatment options: conservative and surgical. The classic surgical procedures are juvenile pubic symphysiodesis (JPS), triple pelvic osteotomy (TPO), total hip replacement (THR), and femoral head and neck resection (FHNE). The aim of this experiment was to present an original technique of filling the acetabulum with a polypropylene implant, resting the femoral neck directly on the mesh. The experiment was performed on eight sheep. The clinical value of the new surgical technique was evaluated using clinical, radiological, and histological methods. This technique helps decrease the loss of limb length by supporting the femoral neck on the mesh equivalent to the femoral head. It also reduces joint pain and leads to the formation of stable and mobile pseudarthrosis. The mesh manifested osteoprotective properties and enabled the formation of a stiff-elastic connection within the hip joint. The method is very cost-effective and the technique itself is simple to perform. PMID:24987672

Bia?ecki, Jacek; Klimowicz-Bodys, Ma?gorzata Dorota; Wierzcho?, Edward; Ko?omecki, Krzysztof

2014-01-01

370

Long-term comparison of Charnley and Stanmore design total hip replacements.  

PubMed

We reviewed the records of the long-term outcome of 208 Charnley and 982 Stanmore total hip replacements (THR) performed by or under the supervision of one surgeon from 1973 to 1987. The Stanmore implant had a better survival rate before revision at 14 years (86% to 79%, p = 0.004), but the difference only became apparent at ten years. The later Stanmore implants did better than the early ones (97% to 92% at ten years, p = 0.005), the improvement coinciding with the introduction of a new cementing technique using a gun. Most of the Charnley implants were done before most of the Stanmore implants so that the difference between the results may in part be explained by improved methods, but this is not the complete explanation since a difference persisted for implants carried out during the same period of time. We conclude that improved techniques have reduced failure rates substantially. This improvement was much greater than that observed between these two designs of implant. Proof of the difference would require a very large randomised controlled trial over a ten-year period. PMID:8836075

Britton, A R; Murray, D W; Bulstrode, C J; McPherson, K; Denham, R A

1996-09-01

371

An analysis of the head-neck taper interface in retrieved hip prostheses.  

PubMed

The purpose of this study was to examine the mating surfaces of femoral heads and stems for evidence of corrosion, and to evaluate the quality of the taper lock of modular hip prostheses. Forty-eight implants with three different designs were evaluated. Group I (26 implants) had a cobalt alloy head and cobalt alloy stem. Group II (ten implants) had a cobalt alloy head and a titanium stem. Group III (12 implants) had a cobalt alloy head with a titanium stem that was coupled in the factory via a shrink fit. The implants were examined under light microscopy and scanning electron microscopy. In cases where the femoral head was still assembled to the stem, pull-off testing was performed using an MTS machine. The average failure load for the pull-off tests for each group of prostheses was as follows: Group I (nine implants) 3,003 N +/- 623 N; Group II (six implants) 4453 N +/- 570 N; and Group III (12 implants) 6859 N +/- 3525 N. The Group III implants required a significantly greater pull-off force than those in Group I (p = 0.002). There was no evidence of corrosion in Group I. In Group II, crevice corrosion was noted in one taper interface and there was fretting in two other tapers. No corrosion was noted in Group III. Improving the tolerances of the mating surfaces may be a key factor in preventing corrosion. This would not only increase the forces that are necessary to debond the matting surfaces, but also decrease corrosion by reducing micromotion and fluid at the taper interface. PMID:8131330

Lieberman, J R; Rimnac, C M; Garvin, K L; Klein, R W; Salvati, E A

1994-03-01

372

The effects on bone cells of metal ions released from orthopaedic implants. A review  

PubMed Central

Summary The increasing use of orthopedic implants and, in particular, of hip and knee joint replacements for young and active patients, has stimulated interest and concern regarding the chronic, long-term effects of the materials used. This review focuses on the current knowledge of the adverse biologic reactions to metal particles released from orthopaedic implants in vivo and in vitro. More specifically, the purpose of this article is to provide an overview of the current literature about the adverse effects of metal particles on bone cells and peri-implant bone. PMID:23858309

Sansone, Valerio; Pagani, Davide; Melato, Marco

2013-01-01

373

Management of hip instability in trisomy 21.  

PubMed

The unstable hip in Trisomy 21 presents with a spectrum of hip instability with different problems at different ages. What links this multiphase problem, in many patients, is the final common pathway of untreated instability, that of a stiff, dislocated, and often-painful hip, leading to significant functional disability. Historically, the results of treating hip instability in Trisomy 21 were variable with a notable frequency of poor results. With an improved understanding of the Trisomy 21 hip in terms of its pathoanatomy and a more contemporary surgical approach to hip reconstruction, much improved results can be expected and indeed have recently been shown. The mainstay of treatment for the habitual dislocation group presenting before 8 years of age is the femoral varus derotation osteotomy. The older group presenting with painful subluxation often show signs of secondary acetabular dysplasia and thus are best treated with redirectional acetabular osteotomy with or without the use of femoral varus derotation osteotomy. The presence of radiographic features of degenerative arthritis in the fixed dislocation group precludes the use of joint-preserving techniques for hip reconstruction, and these patients can achieve excellent results with total joint arthroplasty. The natural history, historical results, assessment, treatment, and management of complications of hip instability in Trisomy 21 are addressed in this paper. PMID:23764791

Kelley, Simon P; Wedge, John H

2013-01-01

374

Process for HIP canning of composites  

NASA Technical Reports Server (NTRS)

A single step is relied on in the canning process for hot isostatic pressing (HIP) metallurgy composites. The composites are made from arc sprayed and plasma sprayed monotape. The HIP can is of compatible refractory metal and is sealed at high vacuum and temperature. This eliminates outgassing during hot isostatic pressing.

Juhas, John J. (inventor)

1990-01-01

375

Revision hip surgery in the elderly  

Microsoft Academic Search

We prospectively analyzed the outcome in 103 consecutive patients undergoing revision hip replacement, dividing the patients into 2 groups according to their age at the time of surgery. There were 45 patients aged 75 years or older and 58 patients aged younger than 75 years. The results of revision hip replacement in terms of pain relief, functional improvement, and patient

G. S. Radcliffe; M. C. Tomichan; M. Andrews; M. H. Stone; M Phil

1999-01-01

376

National trends of hip arthroscopy in Korea.  

PubMed

Hip arthroscopy has been reported to be useful and promising for the treatment of hip pathologies. However, it is not known whether the utilization of hip arthroscopy has increased in Korea. The purpose of this study was to evaluate national trends regarding the utilization of hip arthroscopy in Korea. We retrospectively reviewed nationwide data obtained from the Health Insurance Review and Assessment Service (HIRA). All new admissions for hip arthroscopy are recorded nationwide by HIRA using the ICD-10 code and the code for arthroscopic devices. Using archived data, we determined the trends in utilization of hip arthroscopy between 2007 and 2010. The number of hip arthroscopies increased more than twofold over the study period, from 596 to 1,262. A third of cases were performed in hospitals. Furthermore, a bimodal distribution was observed for men (20 to 24 yr and 45 to 49 yr) and an unimodal distribution for women (50 to 54 yr). Our results show an increasing trends in the utilization of hip arthroscopy from 2007 to 2010, which is in-line with recent findings of increased utilization with the rest of the world. PMID:24550658

Lee, Young-Kyun; Ha, Yong-Chan; Yoon, Byung-Ho; Koo, Kyung-Hoi

2014-02-01

377

Hip Microfracture: Indications, Technique, and Outcomes  

Microsoft Academic Search

Microfracture is a marrow-stimulating technique used in the hip to treat cartilage defects associated with femoroacetabular impingement, instability, or traumatic hip injury. These defects have a low probability of healing spontaneously and therefore often require surgical intervention. Originally adapted from the knee, microfracture is part of a spectrum of cartilage repair options that include palliative procedures such as debridement and

Kevin C. McGill; Charles A. Bush-Joseph; Shane J. Nho

2010-01-01

378

Wagner resurfacing arthroplasty of the canine hip  

Microsoft Academic Search

Twelve surface replacement arthroplasties were performed on the hips of ten mongrel dogs using scaled-down replicas of the Wagner prosthesis. The contralateral hips and two further animals served as nonoperated controls. Animals were killed 5 months postoperatively. Clinical, radiological, histological and fluorochrome-labelling studies were employed to assess the bony and soft tissue reaction to resurfacing arthroplasty. There was no clinical

J. Schatzker; S. B. Goodman; G. Sumner-Smith; V. L. Fornasier; N. Goften; R. S. Bell

1987-01-01

379

Deep recurrent infection of the hip after tumoral resection in an 18–years old male–a case report  

PubMed Central

An 18 years old male was referred to us 4 years after major tumoral surgery. In 2002 he was diagnosed with Ewing sarcoma of the proximal two–thirds of his left femur. Wide resection of the tumor was performed, with a makeshift implant one–stage reconstruction, followed by a combination of chemo and radiotherapy for another 6 months. Eight months after surgery a deep infection of the hip developed, and despite antibiotic treatment and two consecutive debridments and lavage the results were negative. When we first saw the patient in 2006, he still had an active infection in his left hip and a septic general appearance. A two–stage revision was performed and a modular tumoral reconstruction was implanted. At two years follow up the patient presents no signs of recurrence neither of the infection nor of the primary tumor. PMID:20108525

Negrusoiu, M

2008-01-01

380

Bringing aptamers into technologies: Impact of spacer terminations  

NASA Astrophysics Data System (ADS)

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.

Brut, M.; Trapaidze, A.; Estève, A.; Bancaud, A.; Estève, D.; Landa, G.; Djafari-Rouhani, M.

2012-04-01

381

Spacer FinFET: nano-scale CMOS technology for the terabit era  

Microsoft Academic Search

A spacer lithography process technology using a sacrificial layer and a CVD (Chemical Vapor Deposition) spacer layer has been developed, and is demonstrated to achieve sub-40 nm structures with conventional dry etching. The minimum-sized features are defined not by photolithography but by the CVD film thickness. Therefore the spacer lithography technology yields CD (Critical Dimension) variations of minimum-sized features which

Yang-Kyu Choi; Tsu-Jae King; Chenming Hu

2001-01-01

382

Birmingham hip resurfacing: the prevalence of failure.  

PubMed

Despite the increasing interest and subsequent published literature on hip resurfacing arthroplasty, little is known about the prevalence of its complications and in particular the less common modes of failure. The aim of this study was to identify the prevalence of failure of hip resurfacing arthroplasty and to analyse the reasons for it. From a multi-surgeon series (141 surgeons) of 5000 Birmingham hip resurfacings we have analysed the modes, prevalence, gender differences and times to failure of any hip requiring revision. To date 182 hips have been revised (3.6%). The most common cause for revision was a fracture of the neck of the femur (54 hips, prevalence 1.1%), followed by loosening of the acetabular component (32 hips, 0.6%), collapse of the femoral head/avascular necrosis (30 hips, 0.6%), loosening of the femoral component (19 hips, 0.4%), infection (17 hips, 0.3%), pain with aseptic lymphocytic vascular and associated lesions (ALVAL)/metallosis (15 hips, 0.3%), loosening of both components (five hips, 0.1%), dislocation (five hips, 0.1%) and malposition of the acetabular component (three hips, 0.1%). In two cases the cause of failure was unknown. Comparing men with women, we found the prevalence of revision to be significantly higher in women (women = 5.7%; men = 2.6%, p < 0.001). When analysing the individual modes of failure women had significantly more revisions for loosening of the acetabular component, dislocation, infection and pain/ALVAL/metallosis (p < 0.001, p = 0.004, p = 0.008, p = 0.01 respectively). The mean time to failure was 2.9 years (0.003 to 11.0) for all causes, with revision for fracture of the neck of the femur occurring earlier than other causes (mean 1.5 years, 0.02 to 11.0). There was a significantly shorter time to failure in men (mean 2.1 years, 0.4 to 8.7) compared with women (mean 3.6 years, 0.003 to 11.0) (p < 0.001). PMID:20884969

Carrothers, A D; Gilbert, R E; Jaiswal, A; Richardson, J B

2010-10-01

383

[CT and MRI of hip arthroplasty].  

PubMed

Metal-induced artifacts impair image quality of computed tomography (CT) and magnetic resonance imaging (MRI) in patients with hip prostheses. Due to new developments in metal artifact reduction both methods can now be used for evaluation of a painful hip prosthesis. Iterative reconstruction algorithms and dual-energy scans are among the newer CT techniques for artifact reduction, while slice-encoding for metal artifact correction (SEMAC) and multi-acquisition variable-resonance image combination (MAVRIC) have introduced substantial improvements for MRI. Loosening of the hip prosthesis, osteolysis from small wear particles and pseudotumors in metal-on-metal prostheses are specific pathologies in patients with total hip arthroplasty. Other causes of painful hip prostheses are infections, fractures, tendinopathies, tendon ruptures, muscle and nerve alterations and heterotopic ossifications. PMID:24973123

Agten, C A; Sutter, R; Pfirrmann, C W A

2014-07-01

384

Hip Resurfacing Arthroplasty and Perioperative Blood Testing  

PubMed Central

It is standard practice in many institutions to routinely perform preoperative and postoperative haemoglobin level testing in association with hip joint arthroplasty procedures. It is our observation, however, that blood transfusion after uncomplicated primary hip arthroplasty in healthy patients is uncommon and that the decision to proceed with blood transfusion is typically made on clinical grounds. We therefore question the necessity and clinical value of routine perioperative blood testing about the time of hip resurfacing arthroplasty. We present analysis of perioperative blood tests and transfusion rates in 107 patients undertaking unilateral hybrid hip resurfacing arthroplasty by the senior author at a single institution over a three-year period. We conclude that routine perioperative testing of haemoglobin levels for hip resurfacing arthroplasty procedures does not assist in clinical management. We recommend that postoperative blood testing only be considered should the patient demonstrate clinical signs of symptomatic anaemia or if particular clinical circumstances necessitate. PMID:25349744

Smith, Ian

2014-01-01

385

Retrograde peri-implantitis  

PubMed Central

Retrograde peri-implantitis constitutes an important cause for implant failure. Retrograde peri-implantitis may sometimes prove difficult to identify and hence institution of early treatment may not be possible. This paper presents a report of four cases of (the implant placed developing to) retrograde peri-implantitis. Three of these implants were successfully restored to their fully functional state while one was lost due to extensive damage. The paper highlights the importance of recognizing the etiopathogenic mechanisms, preoperative assessment, and a strong postoperative maintenance protocol to avoid retrograde peri-implant inflammation. PMID:20922082

Mohamed, Jumshad B.; Shivakumar, B.; Sudarsan, Sabitha; Arun, K. V.; Kumar, T. S. S.

2010-01-01

386

Ganciclovir implants (Vitrasert).  

PubMed

Ganciclovir implants, used for treating CMV retinitis, are effective in stemming the progression of CMV in patients already diagnosed with the disease. The implants need to be replaced after 32 weeks to lessen the likelihood of relapse. Studies show ganciclovir implants improve eyesight in the majority of patients using them. One large trial, comparing implants with other ganciclovir delivery methods, shows implants to be superior in halting CMV progression. A drawback of the implants is that because they release the drug into the eye only, CMV can spread to other parts of the body. A pill form of the drug is available to use in combination with the implant. PMID:11363393

1996-04-01

387

Influence of head size on the development of metallic wear and on the characteristics of carbon layers in metal-on-metal hip joints  

PubMed Central

Background and purpose Particles originating from the articulating surfaces of hip endoprostheses often induce an inflammatory response, which can be related to implant failure. We therefore analyzed the metal content in capsular tissue from 44 McKee-Farrar metal-on-metal hip prostheses (with 3 different head sizes) and we also analyzed the morphological structure of layers located on articulating surfaces. Methods Atomic absorption spectrometry (AAS) was used to analyze the metal content in capsular tissue. Visually detectable carbon layers located on the articulating surfaces were evaluated using scanning electron microscopy (SEM), energy-dispersive Xray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS). Results Metallic debris was detected in all capsular tissue samples but no statistically significant differences in metal content were found in relation to implant head size. The morphological characteristics of the different layer zones allowed an exact analysis of contact and non-contact areas. Furthermore, surface layers appear to have a protective function because they can prevent sharp-edged particles from damaging the prostheses surface. Interpretation The implant head size does not appear to influence the amount of metallic debris. The layers obviously act like a lubricating agent because the protection function does not occur in regions without layers where the metal surface often shows numerous scratches. As layers are not generated immediately after the implantation of hip prostheses, these findings may at least partially explain the high amount of wear early after implantation. PMID:19421914

Sprecher, Christoph M; Wimmer, Markus A; Milz, Stefan; Taeger, Georg

2009-01-01

388

Do “Premium” Joint Implants Add Value?: Analysis of High Cost Joint Implants in a Community Registry  

Microsoft Academic Search

Background  Numerous joint implant options of varying cost are available to the surgeon, but it is unclear whether more costly implants\\u000a add value in terms of function or longevity.\\u000a \\u000a \\u000a \\u000a \\u000a Questions\\/purposes  We evaluated registry survival of higher-cost “premium” knee and hip components compared to lower-priced standard components.\\u000a \\u000a \\u000a \\u000a Methods  Premium TKA components were defined as mobile-bearing designs, high-flexion designs, oxidized-zirconium designs, those including\\u000a moderately crosslinked

Terence J. Gioe; Amit Sharma; Penny Tatman; Susan Mehle

2011-01-01

389

On the validity of the results from the Swedish National Total Hip Arthroplasty register.  

PubMed

The Swedish National Total Hip Arthroplasty Register contains more than 200,000 primary and secondary hip replacements. The failure end-point definition is revision. The aim of this thesis was to validate the results presented by the register and to study the outcome of hip replacement surgery in Sweden. The hypothesis was firstly that the number of failure reported to the Swedish THA register are valid and secondly that adding clinical and radiographic failure criteria will dramatically decrease the survival rate for THR implants. The study consisted of three parts with 2-10 years follow-up of patients with total hip replacements (THR). In part I, three general health questionnaires (Nottingham Health Profile, SF-36, EuroQol) and two disease-specific instruments (WOMAC, Harris Hip Score) were tested for validity and reliability (n = 62). The results showed the disease specific questionnaires are at least as valid and reliable as the general instruments are. In part II, all THRs reported to the Swedish THA register 1986 to 1994 (84,884 primary and 10,176 revision hip replacements) were compared with the data from the Discharge register and the Cause of Death register in Sweden. 2,604 patients were randomly selected from the Discharge register to determine if they had undergone any revision surgery. The study showed that the Swedish THA register covers 94% of the revisions actually performed in Sweden and the results did not differ significantly from the data in the Discharge register and the results reported by the patients. In part III, 1,056 patients from the selected cohort were studied further concerning general health and disease-specific health, using the Nottingham Health Profile, SF-36 and WOMAC. An age and gender matched subcohort of 344 patients were then examined clinically, using the Harris Hip Score, and radiographically. The clinical and radiographic failure rates were in several tests as high as the revision rates documented in the Swedish THA register. The clinical results were, however, dependent on demographics, the definition of clinical failure and the scoring system used. The results presented by the register with revision as failure end-point give an exact but limited information about the quality of hip replacement surgery in Sweden. PMID:11138472

Söderman, P

2000-12-01

390

Metal ion levels in large-diameter total hip and resurfacing hip arthroplasty-Preliminary results of a prospective five year study after two years of follow-up  

PubMed Central

Background Metal-on-metal hip resurfacing is an alternative to metal-on-metal total hip arthroplasty, especially for young and physically active patients. However, wear which might be detected by increased serum ion levels is a matter of concern. Methods The aims of this preliminary study were to determine the raise of metal ion levels at 2-years follow-up in a prospective setting and to evaluate differences between patients with either resurfacing or total hip arthroplasty. Furthermore we investigated if the inclination of the acetabular component and the arc of cover would influence these findings. Therefore, 36 patients were followed prospectively. Results The results showed increments for Co and Cr in both implant groups. Patients treated with large-diameter total hip arthroplasty showed fourfold and threefold, respectively, higher levels for Co and Cr compared to the resurfacing group (Co: p?hip replacement. PMID:22494794

2012-01-01

391

[Hip surgery: local tissue reactions].  

PubMed

Present extent of total hip prostheses, protracted course of first operations lead to pathological studies on local tissue reactions, sign of the failure or of the damaging of the artificial hip. Another pathology, often as intricate, is observed after more conservative surgery: high femoral osteotomies, cup arthroplasties, femoral metallic prostheses. Failure of an high femoral osteotomy shows a running of osteoarthritic lesions the topography of which is always modified by the new orientation of the articular bearing segment. Osteosclerosis, osteoarthritic cysts may develop on a preexisting osteophytosis. Osteonecrosis or bone resorption are sometimes found. Anatomical results in case of a successful osteotomy are scarce. Fibrous layer eventually quoted as a guide to the development of fibrocartilage is more often associated with osteoclast mediated bone loss. Efficient bone remodelling is assumed only, today, by radiological proof. Failures of cup arthroplasties induce femoral bone or acetabular cartilage lesions which are different according to the surgical technic. Some are marked by cartilage destruction of the acetabula or by a cup dislodgement. Bone structure in those cases shows under the cup a good remodelling with a fibrous or fibrocartilaginous mantle originating from the bone marrow spaces and the capsular attachment. In other cases, the femoral head presents areas of superficial or total osteonecrosis, signs of intense osteoclastic activity, cleaving of the fibrous surface and eventually metallic debris or cement induced histiocytic granuloma. A fibrous layer may develop between the cup and the acetabula. Femoral metallic prostheses may damage in some years cartilage of the acetabula. Osteoarthritic bone remodelling is sometimes observed in close contact with the metallic collar. Lesions of capsular tissues are eventually represented by metallic debris or an histiocytic granuloma due to cement anchorage. Material received at the time of surgical revision on total hip arthroplasties concerns chiefly the newly formed capsular and synovial tissues. Their appearance is quite similar to the tissular layers found between prosthetic material and bone or cement. For the pathologist, main inquiries are the rule out of an infection, the extent and course of the macrophage or giant cell response, the nature of wear debris or of the products of corrosion and the histological factors contributing to the loosening of the prosthetic components. It should be stressed that any physiopathological schedule of an artificial hip failure is a topographical and dynamic problem only partly resolved by studying autopsy material. PMID:3893449

Forest, M; Courpied, J P; Lefloch, P; Carlioz, A; Abelanet, R; Postel, M

1985-01-01

392

Assessment of Patients with a DePuy ASR Metal-on-Metal Hip Replacement: Results of Applying the Guidelines of the Spanish Society of Hip Surgery in a Tertiary Referral Hospital  

PubMed Central

The prognosis associated with the DePuy ASR hip cup is poor and varies according to the series. This implant was withdrawn from use in 2010 and all patients needed to be assessed. We present the results of the assessment of our patients treated with this device, according to the Spanish Society of Hip Surgery (SECCA) algorithm published in 2011. This retrospective study evaluates 83 consecutive ASR cups, followed up at a mean of 2.9 years. Serum levels of chromium and cobalt, as well as the acetabular abduction angle, were determined in order to assess their possible correlation with failure, defined as the need for revision surgery. The mean Harris Hip Score was 83.2 (range 42–97). Eight arthroplasties (13.3%) required revision due to persistent pain and/or elevated serum levels of chromium/cobalt. All the cups had a correct abduction angle, and there was no correlation between elevated serum levels of metal ions and implant failure. Since two previous ASR implants were exchanged previously to the recall, the revision rate for ASR cups in our centre is 18.2% at 2.9 years. PMID:25431677

Fernández-Valencia, Jenaro; Gallart, Xavier; Bori, Guillem; Ramiro, Sebastián Garcia; Combalía, Andrés; Riba, Josep

2014-01-01

393

Significantly reduced leg length discrepancy and increased femoral offset by application of a head-neck adapter in revision total hip arthroplasty.  

PubMed

Head-neck adapters in total hip arthroplasty (THA) promise the reconstruction of optimal femoral offset and leg length in revision THA while retaining stable implants. Radiological parameters after adapter implantation in THA revision were determined in 37 cases. Significant reduction of leg length discrepancy and improvement of femoral offset (P < 0.001) were found. Clinical endpoints were determined in 20 cases (mean follow-up 4.0 years). Clinical scores were rather poor (median Harris hip score 54, WOMAC score 41) due to age and comorbidities, postoperative dislocation occurred in 3 cases. Only one stable femoral stem had to be revised due to recurrent postoperative dislocation. In conclusion, a head-neck adapter can be a valuable tool in certain cases of revision THA with acceptable dislocation rates while allowing the retention of stable implants. PMID:24405617

Woelfle, Julia V; Fraitzl, Christian R; Reichel, Heiko; Wernerus, Dirk

2014-06-01

394

Percutaneous compression plating versus gamma nail for the treatment of pertrochanteric hip fractures  

PubMed Central

The objective of this study is to compare percutaneous compression plating (PCCP) device with standard gamma nail (GN). A sample was prospectively followed and compared to a historical cohort: 82 intertrochanteric hip fractures in 81 patients treated with PCCP in 2004 versus 51 hip fractures treated with GN in 2003 (AO type 31A1, 31 A2). The main outcome measures were: surgery times, blood loss (Hb serum level and transfusions), complication, costs, for a 1-year follow-up. The minimally invasive PCCP technique resulted in a lower blood loss and consequently lower transfusion need (statistically significant), fewer implant-related complications and comparable surgery times. Overall surgical costs were lower for a comparable outcome in terms of healing and surgical time. PMID:18427918

Antonini, Guido; Delle Rose, Giacomo; Crippa, Cornelio

2008-01-01

395

Thirty years of experience with alumina-on-alumina bearings in total hip arthroplasty  

PubMed Central

Alumina-on-alumina bearings in total hip arthroplasty have been developed in an attempt to minimise debris and the occurrence of osteolytic lesions. The outstanding tribological properties of this bearing system are explained by low surface roughness, high hardness for major scratch resistance, and high wettability. Since the 1970s, technological improvements in the manufacturing process of alumina components together with a better understanding of Morse taper technology have provided a surgical grade material with high density, high purity and small grains. Published studies on the outcome of total hip arthroplasty performed with this new generation of implants showed high survivorship especially in young and active patients, with survival rates free of revision of 90.8% to 97.4% at ten years. However, concern remains over ceramic liner fracture and squeaking, which has been noted recently with increasing prevalence. This review will discuss the current knowledge on the use of alumina-on-alumina bearings. PMID:21191579

Zaoui, Amine; Zadegan, Frédéric; Sedel, Laurent; Nizard, Rémy

2010-01-01

396

The neuromuscularly challenged patient: total hip replacement is now an option.  

PubMed

Degenerative problems of the hip in patients with childhood and adult onset neuromuscular disorders can be challenging to treat. Many orthopaedic surgeons are reluctant to recommend total hip replacement (THR) for patients with underlying neuromuscular disorders due to the perceived increased risks of dislocation, implant loosening, and lack of information about the functional outcomes and potential benefits of these procedures in these patients. Modular femoral components and alternative bearings which facilitate the use of large femoral heads, constrained acetabular components and perhaps more importantly, a better understanding about the complications and outcomes of THR in the patient with neuromuscular disorders, make this option viable. This paper will review the current literature and our experience with THR in the more frequently encountered neuromuscular disorders. PMID:25381404

Kraay, M J; Bigach, S D

2014-11-01

397

Assessment of accuracy of marker ball placement in pre-operative templating for total hip arthroplasty.  

PubMed

We report the accuracy of positioning of the calibration ball in the process of pre-operative templating for total hip arthroplasty (THA). The ball should be placed in the coronal plane of the hip to provide suitable accuracy. We reviewed 112 post-operative THA radiographs where a calibration ball had been placed. We templated the femoral head size of the implant after calibrating the templating system from the ball. The calibrated femoral head diameter was compared to the known prosthetic head size. A percentage error was calculated. Overall, incorrect placement of the calibration ball resulted in a mean percentage error in templating of 6.8% (median 5.7%; range 0-26%). Such error carries implications with the templating process and may result in incorrect component sizes, leg lengths and offset. PMID:24736293

Sinclair, Victoria F; Wilson, James; Jain, Neil P M; Knowles, David

2014-08-01

398

Reconstruction of the Acetabulum in Developmental Dysplasia of the Hip in total hip replacement  

PubMed Central

Developmental dysplasia of the hip (DDH) or congenital hip dysplasia (CDH) is the most prevalent developmental childhood hip disorder. It includes a wide spectrum of hip abnormalities ranging from dysplasia to subluxation and complete dislocation of the hip joint. The natural history of neglected DDH in adults is highly variable. The mean age of onset of symptoms is 34.5 years for dysplastic DDH, 32.5 years for low dislocation, 31.2 years for high dislocation with a false acetabulum, and 46.4 years for high dislocation without a false acetabulum. Thorough understanding of the bony and soft tissue deformities induced by dysplasia is crucial for the success of total hip arthroplasty. It is important to evaluate the existing acetabular deformity three-dimensionally, and customize the correction in accordance with the quantity and location of ace tabular deficiencies. Acetabular reconstruction in patients with DDH is challenging. Interpretation of published data is difficult and should be done with caution because most series include patients with different types of hip disease. In general, the complication rate associated with THA is higher in patients with hip dysplasia than it is in patients with osteoarthritis. Overall, clinical and functional outcomes following THA in patients hip dysplasia (DDH) differ from those treated for primary hip osteoarthritis, possibly due to the lower age and level of activity. Although function scores decline with age, the scores for pain and range of motion presented with a statistically significant improvement in the long-term. PMID:25386570

Sakellariou, Vasileios I.; Christodoulou, Michael; Sasalos, Gregory; Babis, George C.

2014-01-01

399

Wear reduction effect on ultra-high-molecular-weight polyethylene by application of hard coatings and ion implantation on cobalt chromium alloy, as measured in a knee wear simulation machine  

Microsoft Academic Search

The most important factor affecting performance and longevity of hip joint and knee implants is the wear rate of the ultra-high-molecular-weight polyethylene (UHMWPE) component. UHMWPE wear debris has been linked to complications including tissue inflammation, bone loss (osteolysis) and implant loosening. Reduction of debris has been addressed by investigating new polyethylene formulations, manufacturing and finishing processes, including surface treatments and

J. I. Oñate; M. Comin; I. Braceras; A. Garcia; J. L. Viviente; M. Brizuela; N. Garagorri; J. L. Peris; J. I. Alava

2001-01-01

400

Correlation of corrosion and biomechanics in the retrieval of a single modular neck total hip arthroplasty design: modular neck total hip arthroplasty system.  

PubMed

Increased modularity of total hip arthroplasty components has occurred, with theoretical advantages and disadvantages. Recent literature indicates the potential for elevated revision rates of modular neck systems and the potential for local pseudotumor and metallosis formation at the modular neck/stem site. Retrieval analysis of one modular neck implant design including SEM (SCANNING ELECTRON MICROSCOPY) assessment was done and correlated with FEA (finite element analysis) as well as clinical features of patient demographics, implant and laboratory analysis. Correlation of the consistent corrosion locations to FEA indicates that the material and design features of this system may result in a biomechanical reason for failure. The stem aspect of the modular neck/stem junction may be at particular risk. PMID:25060562

Lanting, Brent A; Teeter, Matthew G; Vasarhelyi, Edward M; Ivanov, Todor G; Howard, James L; Naudie, Douglas D R

2015-01-01

401

Accuracy and Feasibility of Dual Fluoroscopy and Model-Based Tracking to Quantify In Vivo Hip Kinematics During Clinical Exams  

PubMed Central

Accurate measurements of in-vivo hip kinematics may elucidate the mechanisms responsible for impaired function and chondrolabral damage in hips with femoroacetabular impingement (FAI). The objectives of this study were to quantify the accuracy and demonstrate the feasibility of using dual fluoroscopy to measure in-vivo hip kinematics during clinical exams used in the assessment of FAI. Steel beads were implanted into the pelvis and femur of two cadavers. Specimens were imaged under dual fluoroscopy during the impingement exam, FABER test, and rotational profile. Bead locations measured with model-based tracking were compared to those measured using dynamic radiostereometric analysis. Error was quantified by bias and precision, defined as the average and standard deviation of the differences between tracking methods, respectively. A normal male volunteer was also imaged during clinical exams. Bias and precision along a single axis did not exceed 0.17 and 0.21 mm, respectively. Comparing kinematics, positional error was less than 0.48 mm and rotational error was less than 0.58°. For the volunteer, kinematics were reported as joint angles and bone-bone distance. These results demonstrate that dual fluoroscopy and model-based tracking can accurately measure hip kinematics in living subjects during clinical exams of the hip. PMID:24584728

Kapron, Ashley L.; Aoki, Stephen K.; Peters, Christopher L.; Maas, Steve A.; Bey, Michael J.; Zauel, Roger; Anderson, Andrew E.

2014-01-01

402

A multicenter retrieval study of the taper interfaces of modular hip prostheses.  

PubMed

A multicenter retrieval analysis of 231 modular hip implants was done to investigate the effects of material combination, metallurgic condition, flexural rigidity, head and neck moment arm, neck length, and implantation time on corrosion and fretting of modular taper surfaces. Scores for corrosion and fretting were assigned to medial, lateral, anterior, and posterior quadrants of the necks, and proximal and distal regions of the heads. Neck and head corrosion and fretting scores were found to be significantly higher for mixed alloy versus similar alloy couples. Moderate to severe corrosion was observed in 28% of the heads of similar alloy couples and 42% of the heads of mixed alloy couples. Differences in corrosion scores were observed between components made from the same base alloy, but of different metallurgic conditions. Corrosion and fretting scores tended to be higher for heads than necks. Implantation time and flexural rigidity of the neck were predictors of head and neck corrosion and head fretting. The results of this study suggest that in vivo corrosion of modular hip taper interfaces is attributable to a mechanically-assisted crevice corrosion process. Larger diameter necks will increase neck stiffness and may reduce fretting and subsequent corrosion of the taper interface regardless of the alloy used. Increasing neck diameter must be balanced, however, with the resulting loss of range of motion and joint stability. PMID:12151892

Goldberg, Jay R; Gilbert, Jeremy L; Jacobs, Joshua J; Bauer, Thomas W; Paprosky, Wayne; Leurgans, Sue

2002-08-01

403

Accuracy of an adjustable patient-specific guide for acetabular alignment in hip replacement surgery (Optihip).  

PubMed

Implant malalignment in hip arthroplasty increases the risk of revision surgery due to problems such as hip instability, wear, and impingement. Traditional instrumentation lacks accuracy and does not individualize the goal. Computer-assisted surgery (CAS) and patient-specific solutions improve accuracy but add considerably to the cost, amongst other drawbacks. We developed an adjustable mechanical device, called Optihip, which is set to a patient-specific goal preoperatively and is independent of pelvis position intraoperatively. The purpose of the present study was to evaluate Optihip's accuracy ex vivo. Acetabular components were implanted into six cadaveric specimens, 12 hips, by two surgeons, with the device individually adjusted according to preoperative templating on computed tomography (CT) images relative to defined acetabular rim landmarks; options also exist for templating on single or biplanar X-rays. Intraoperatively, the device was positioned on the corresponding anatomical landmarks allowing the insertion of a guide pin, which then defined the desired orientation of the acetabular cup during impaction. Mean absolute difference between the preoperatively planned cup alignment and final acetabular cup orientation, measured from postoperative CT images, was 2.5±1.2° for inclination and 2.5±2.2° for version with maximum values of 4.7° and 6.8°, respectively. Compared with previous in vivo reports, Optihip guided the acetabular cup orientation more accurately than conventional hip arthroplasty, and comparably to CAS or patient-specific systems, while fitting into the normal surgical workflow. Although clinical testing is required to confirm these experimental results, the positive ex vivo accuracy suggests good potential for improving revision rates and patient functional outcome. PMID:25313024

Shandiz, Mohsen Akbari; MacKenzie, James R; Hunt, Stephen; Anglin, Carolyn

2014-09-01

404

[50 years of total hip prosthesis--a tribute to Prof. Sir John Charnley].  

PubMed

November 2012 marked the 50th anniversary of the first implantation of a successful and long-lived hip endoprosthesis, which was performed by Prof Sir John Charnley in the "Centre for Hip Surgery" at a small country place in the north-west England. John Charnley (1911-1982) finished medical school at the Victoria University of Manchester in 1935, and than started training in orthopaedics at the Manchester Royal Infirmary, and completed it after the Second World War, in which he served as a volunteer. After that he continued working in the same hospital, and, apart from that he worked as a lecturer at the University of Manchester, and from 1949 as a visiting surgeon in the Wrightington Hospital. In 1958 Charnley decided to put his efforts into the development of hip replacement research and surgery, and initiated the foundation of the "Centre for Hip Surgery" with Biomechanical laboratory in the Wrightington Hospital in 1960, where the intesive basic and clinical research started, and becuase of that Charnley in 1962 left Manchester and moved with a full time practice at the Wrightington Hospital. That period of research time was not easy, there were many "trial and tribulations", but, owing to the tenacity and inventive mind of Charnley, in 1962 a new prosthesis consisting of a cemented metal stem with a 22 mm head articulating with a cemented polyethilene acetabular component, and with a low frictional torque was designed. The first such prosthesis, which later produced excellent long-term results, was implanted on November 22nd, 1962, and today, when we look back over a distance of fifty years, we can conclude that that day could be considered as a beginning of a modem aloarthroplastic surgery, and certainly as one of the greatest orthopaedic advance in the whole of the 20th century; and all that was initiated and promoted by Prof. Sir John Charnley. PMID:24669557

Miki?, Zelimir Dj; Lesi?, Aleksandar R

2013-01-01

405

An experimental study of damage accumulation in cemented hip prostheses.  

PubMed

OBJECTIVE: To develop a methodology to characterize the pattern of crack initiation and damage accumulation in intramedullary fixated cemented prostheses. DESIGN: An experimental physical model of intramedullary fixation was developed which both represents the implant structure and permits monitoring of fatigue crack growth. BACKGROUND: Many joint replacement prostheses are fixed into the medullary cavity of bones using a poly(methylmethacrylate) 'bone cement', which forms a mantle around the prosthesis and locks it to the bone. The endurance of the replacement is, to a great extent, determined by the mechanical durability of the cement and the implant interfaces under cyclic stresses generated by dynamic loading. The cement mantle is subjected to complex multiaxial stresses which vary in particular distribution depending on the prosthesis design. METHODS: Damage accumulation is reported in terms of the number of cracks, the location of cracks, and the rate of crack growth. RESULTS: The results clearly show the nature of damage accumulation in the cement mantle, and that many of the cracks which propagate within the cement mantle are related to cement porosity. CONCLUSION: This study gives experimental evidence to support the hypothesis of a damage accumulation failure scenario in cemented hip reconstructions. RELEVANCE: Cementing is the most popular technique for the fixation of joint replacement prosthesis. However, the sequence of events leading to the failure of cemented fixation is not fully understood. In this paper it is shown that damage accumulation can be directly monitored in an experimental model of cemented intramedullary fixation. PMID:11415623

McCormack, B A O; Prendergast, P J; Gallagher, D G

1996-06-01

406

The effects of static charge in spacer devices on glucocorticosteroid aerosol deposition in asthmatic patients.  

PubMed

Electrostatic charge in plastic spacer devices has been shown in vitro to reduce delivery of asthma medications intended for inhalation, but the effect of static charge on in vivo drug deposition is unknown. A six-way randomized crossover study was conducted in 10 mild asthmatic patients. Two plastic spacers (Nebuhaler and Volumatic) and one metal spacer (Nebuchamber) were tested. The spacers were used either "primed" or "unprimed". Priming was performed by firing 20 doses of placebo aerosol into a new spacer, hence coating the inner surface with surfactant and minimizing static charge. Unprimed spacers were new and were not treated. Pressurized aerosol canisters delivering budesonide (200 microg Pulmicort) were radiolabelled with the radionuclide 99mTc and lung deposition was measured by gamma scintigraphy. The radiolabel was shown to be a valid marker for the drug substance prior to the clinical phase of the study. Priming significantly increased mean whole lung deposition following inhalation from plastic spacers (Nebuhaler primed 37.7% and unprimed 26.7%, p=0.01; Volumatic primed 32.0% and unprimed 22.1%, p=0.02). Priming had no effect on the mean whole lung deposition following inhalation from the Nebuchamber (primed 33.5% and unprimed 32.9%). Lung deposition in vivo from plastic spacer devices will vary according to the electrostatic charge on the spacer walls. Priming reduces retention of drug on plastic spacer devices and increases lung deposition. Metal spacers are not susceptible to static charge, which should result in more predictable lung deposition. PMID:9596110

Kenyon, C J; Thorsson, L; Borgström, L; Newman, S P

1998-03-01

407

Poly(2-methacryloyloxyethyl phosphorylcholine)-grafted highly cross-linked polyethylene liner in primary total hip replacement: one-year results of a prospective cohort study.  

PubMed

To control particle-induced osteolysis in total hip replacement (THR), we developed a new technique to graft poly(2-methacryloyloxyethyl phosphorylcholine) onto the surface of polyethylene liners. A prospective cohort study was conducted to investigate the clinical safety of this novel bearing surface. Between April 2007 and September 2008, we recruited a prospective consecutive series of 80 patients in five participating hospitals. These patients received a cementless THR; a 26-mm-diameter cobalt-chromium-molybdenum alloy ball and a poly(2-methacryloyloxyethyl phosphorylcholine)-grafted cross-linked polyethylene liner were used for the bearing couplings. These individuals were followed a year postoperatively. An evaluation of clinical performance was conducted through an assessment of hip joint function based on the evaluation chart authorized by the Japanese Orthopaedic Association. No patients were lost to follow-up. No adverse events were found to be correlated with the implanted liners. The average hip joint function score improved from 43.2 preoperatively to 91.7 postoperatively at 1 year. There was no implant migration nor periprosthetic osteolysis detected on radiographic analysis. On the basis of our results, we conclude that poly(2-methacryloyloxyethyl phosphorylcholine)-grafted cross-linked polyethylene liners are a safe implant option for hip replacement surgery for short-term clinical use. PMID:23238557

Takatori, Yoshio; Moro, Toru; Kamogawa, Morihide; Oda, Hiromi; Morimoto, Shuhei; Umeyama, Takashige; Minami, Manabu; Sugimoto, Hideharu; Nakamura, Shigeru; Karita, Tatsuro; Kim, Juntaku; Koyama, Yurie; Ito, Hideya; Kawaguchi, Hiroshi; Nakamura, Kozo

2013-06-01

408

Design of Composite Hip Prostheses Considering the Long-Term Behavior of the Femur  

NASA Astrophysics Data System (ADS)

A design method for the hip prosthesis is proposed which can alleviate problems associated with stress shielding, proximal loosening and the high stress of bone-implant interfaces after total hip replacement. The stress shielding which may lead to bone resorption, can cause a loosening of the stem and a fracture of femoral bone. Generally the composites were more suitable for hip prosthesis material in the long-term stability than metallic alloy because design cases of composite materials produced less stress shielding than titanium alloy. A bone remodeling algorithm was implemented in a nonlinear finite element program to predict the long-term performance of the hip prosthesis. The three neck shapes and three cross sections of composite hip were examined. It was found that the stress concentration in the distal region of the titanium stem which may cause the patient's thigh pains was reduced using composite material. The head neck shape was closely related with the cortical bone resorption and the cancellous bone apposition at proximal region whereas the cross-section was closely related with the relative micromotion between interfaces. The convex head neck type with the quadrangle cross-section produced less subsidence at proximal region on the medial side than the others. For all composite material cases, the cancellous bone apposition occurred at partial interfaces, which may result in a stable bio-fixation. The design performances of the convex neck head type with the hexagonal cross-section designed to insure the long-term stability were found to be more suitable than the others.

Lim, Jong Wan; Jeong, Jae Youn; Ha, Sung Kyu

409

Thin Dielectric Spacer for the Monolithic Integration of Bulk Germanium or  

E-print Network

Thin Dielectric Spacer for the Monolithic Integration of Bulk Germanium or Germanium Quantum Wells germanium (Ge) or Ge quantum wells with silicon-on-insulator (SOI) waveguides through selective epitaxy process to realize sub-30-nm spacers. Index Terms: Integrated optoelectronics, germanium, quantum wells

Miller, David A. B.

410

22nm half-pitch patterning by CVD spacer self alignment double patterning (SADP)  

Microsoft Academic Search

Self-aligned double patterning (SADP) is a patterning technique that uses CVD spacers formed adjacent to a core (template) pattern that is defined by conventional lithography. After stripping the core (template) material, the spacers serve as a hardmask with double the line density of the original lithographically defined template. This integration scheme is an alternative to conventional double patterning for extending

Chris Bencher; Yongmei Chen; Huixiong Dai; Warren Montgomery; Lior Huli

2008-01-01

411

Study of heat transfer in multilayer insulations based on composite spacer materials  

NASA Astrophysics Data System (ADS)

The calorimeter was developed to study the heat conduction coefficient of multilayer insulations and optical characteristics of their shields and spacers. Data on heat conduction of insulation with spacers of various compositions were obtained. Experimental and theoretical analyses were carried out on radiation and contact components of heat transfer.

Mikhalchenko, R. S.; Getmanets, V. F.; Pershin, N. P.; Batozskii, Yu. V.

412

Novel electromagnetic technique for repositioning of coolant tube spacers in CANDU nuclear reactors  

Microsoft Academic Search

A novel electromagnetic technique to reposition the coolant tube spacers in the fuel channels of CANDU nuclear reactors was successfully developed in the fall of 1983 at Ontario Hydro Research Division. The need to reposition dislocated spacers in noncommissioned reactors was discovered subsequent to the rupture of a pressure tube in one reactor at the Pickering Nuclear Generator Station in

Joseph H. Dableh

1986-01-01

413

Transcriptional regulator-mediated activation of adaptation genes triggers CRISPR de novo spacer acquisition.  

PubMed

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

Liu, Tao; Li, Yingjun; Wang, Xiaodi; Ye, Qing; Li, Huan; Liang, Yunxiang; She, Qunxin; Peng, Nan

2015-01-30

414

Effect of Structure on the Mechanical Behaviors of Three-Dimensional Spacer Fabric Composites  

NASA Astrophysics Data System (ADS)

Three-dimensional (3-D) spacer fabric composite is a newly developed sandwich structure, the reinforcement of which is integrally woven by advanced textile technique. Two facesheets of 3-D spacer fabric are connected by continuous fibers, named pile in the core, providing excellent properties like outstanding integrity, debonding resistance, light weight, good designability and so on. Usually the 3-D spacer fabric composite without extra reinforcement is a kind of core material. In comparison with the facesheet reinforced spacer fabric composite, here the composite without additional weaves is called mono-spacer fabric composite. In this paper, two kinds of mono-spacer fabric composites with integrated hollow cores have been developed, one with 8-shaped piles and the other with corrugated piles. The mechanical characteristics and the damage modes of these mono-spacer fabric composites under different load conditions have been investigated. Besides, effects of pile height, pile distribution density and pile structure on the composites mechanical performances were analyzed. It is shown that the mechanical performances of mono-spacer fabric composites can be widely adapted to the respective requirements through the choice of the structural factors.

Li, Min; Wang, Shaokai; Zhang, Zuoguang; Wu, Boming

2009-02-01

415

The Effect of Charge-Reversal Amphiphile Spacer Composition on DNA and siRNA Delivery  

E-print Network

The Effect of Charge-Reversal Amphiphile Spacer Composition on DNA and siRNA Delivery Xiao April 7, 2010 A series of charge-reversal amphiphiles with different spacers separating the headgroup from the hydrophobic chains are described for delivery of DNA and siRNA. Among them, the amphiphiles

416

Improving electricity production in tubular microbial fuel cells through optimizing the anolyte flow with spiral spacers  

E-print Network

produced more electricity than the one without the spiral spacers at different recirculation rates in an aeration tank of a municipal wastewater treatment plant confirmed the advantage of using the spiral spacers and higher recirculation rates might not be effective to increase electricity generation under some condi

417

Numerical simulation of hydraulic characteristics of coolant in rod spacer grids  

Microsoft Academic Search

Thermal hydraulic performance analysis of fuel rod bundle with spacer grids takes important role among the pressure water reactor (PWR) design and safety operation. Due to its intrinsic complex geometric configuration, previous studies were almost based on one-dimensional code and many simplifications had to be made to make simulations manageable. In the present paper, the intact and simplified spacer grids

Ma Teng-da; He-yi Zeng; Yun Guo

2011-01-01

418

Catastrophic failure of ceramic-on-ceramic total hip arthroplasty presenting as squeaking hip  

PubMed Central

A 68-year-old woman with osteoarthritis had a ceramic-on-ceramic left total hip arthroplasty, including ceramic femoral head and acetabular liner. At 5?years after surgery, the patient developed onset of a very loud squeaking noise, which could be heard 25?m from her, associated with limited hip movement. Findings at revision surgery included a broken ceramic femoral head component, complete wear of the ceramic acetabular component, and black wear debris. Squeaking hip after ceramic-on-ceramic total hip arthroplasty may be associated with catastrophic failure of the arthroplasty components. PMID:23429031

Malem, David; Nagy, Mathias Thomas; Ghosh, Sabyasachi; Shah, Bhavik

2013-01-01

419

Total hip arthroplasty after treatment of pseudojoint infection in a patient with a highly dislocated hip.  

PubMed

Infection at the pseudoacetabulum in a patient with a high hip dislocation has not been reported previously in the English literature. We report a case of total hip arthroplasty in a 28-year-old female who presented to us with hip pain following debridement of the infected pseudojoint in a case of neglected developmental dysplasia of the hip. The infection was treated with thorough debridement and drainage. However, even after achieving complete infection control, this patient complained of disabling right hip joint pain. Total hip arthroplasty with subtrochanteric osteotomy was performed to relieve the pain and improve gait. After surgery, the patient's symptoms were relieved. We consider that in this case of acute pseudojoint infection simple arthrotomy and debridement combined with irrigation and drainage provide effective treatment. But muscle weakness and more increased joint laxity can cause hip pain even after infection control. So total hip arthroplasty is likely to be necessary after the infection has been controlled in a patient with a highly dislocated hip. PMID:23878754

Park, Kyung-Soon; Seon, Jong-Keun; Nah, Seon-Yoon; Yoon, Taek-Rim

2013-01-01

420

Metal Ion Levels in Maternal and Placental Blood After Metal-on-Metal Total Hip Arthroplasty.  

PubMed

There is concern regarding elevated metal ion levels in the blood during pregnancy and the potential fetal effects in women with metal-on-metal (MOM) implants. We obtained maternal and umbilical cord blood samples from 3 patients with a MOM hip arthroplasty and 7 control subjects without any metallic implants. Serum metal ion levels including chromium, cobalt, titanium, and nickel were tested using high-resolution sector-field inductively-coupled plasma-mass spectrometry. Mothers with MOM-bearing implants had significantly elevated levels of serum cobalt and chromium compared with control-group mothers, and umbilical cord blood from mothers with MOM implants also had significantly higher serum metal ion levels compared with control-group mothers. The results of this study show that circulating serum levels of metal ion degradation products from MOM bearings cross the placenta and expose the fetus to metal ions. However, the placenta exerts a modulatory effect on cord blood, resulting in decreased levels compared with maternal samples (approximately 15% of maternal chromium and 50% of maternal cobalt). Physicians and women of child-bearing age should be aware of this potential effect when considering the use of MOM-bearing implants. PMID:25490017

Novak, Clifford C; Hsu, Andrew R; Della Valle, Craig J; Skipor, Anastasia K; Campbell, Patricia; Amstutz, Harlan C; Jiranek, William A; Onyike, Aham; Pombar, Xavier F; Jacobs, Joshua J

2014-12-01

421

[Dislocation after total hip arthroplasty--the problem is still present, reasons and treatments].  

PubMed

Dislocation after total hip replacement remains a significant problem in orthopedic practice. Despite the use of more modem implants risk of instability is estimated at a few percent for primary treatment and for several procedures. The standard procedure in case of the first dislocation is reduction of the prosthesis in general anesthesia. Further investigation is individual, each case must be thoroughly examined for proper execution of the original surgery and the risk of the next dislocation. Regardless of the subsequent procedures performed a key role in the event of instability prosthesis plays properly conducted rehabilitation and patient education. PMID:24779210

Pep?o?ski, Artur; P?omi?ski, Janusz

2014-03-01

422

Vibration of the Package of Rods Linked by Spacer Grids  

NASA Astrophysics Data System (ADS)

This paper deals with modelling and vibration analysis of the large package of identical parallel rods which are linked by transverse springs (spacer grids) placed on several level spacings. The vibration of rods is caused by the support plate motion. The rod discretization by FEM is based on Rayleigh beam theory. With respect to cyclic and central package rod symmetry, the system is decomposed to identical revolved rod segments. The modal synthesis method with condensation of the rod segments is used for modelling and determination of steady forced vibration of the whole system. The presented method is the first step to modelling of the nuclear fuel assembly vibration caused by kinematical excitation determined by motion of the support plates which are part of the reactor core.

Zeman, V.; Hlavá?, Z.

423

Design compliance for spacer is dielectric (SID) patterning  

NASA Astrophysics Data System (ADS)

Self-Aligned Double Patterning (SADP) is a strong candidate for the lower-Metal layers of the 14 nm node. Compared to Litho-Etch-Litho-Etch (LELE) Double Patterning, SADP has lower LWR (line-width roughness), tighter line-end minimum spacing, and lower sensitivity to overlay errors. However, design for SADP is more restricted than for LELE. This work explores the design of layouts compatible with the Spacer Is Dielectric (SID) flavor of SADP. It is easy to find layouts that are LELE-compliant but not SID-compliant. One reason is that polygon stitching is not allowed in SID. Another is that certain drawn-space values are forbidden in SID. In this paper, we will write down some basic rules for SID-compliant design, and introduce some SID-printing artifacts that may be worrisome.

Luk-Pat, Gerard; Miloslavsky, Alex; Painter, Ben; Lin, Li; De Bisschop, Peter; Lucas, Kevin

2012-03-01

424

Noncollinear coupling of iron layers through native iron oxide spacers  

SciTech Connect

We have found a magnetic superstructure in multilayers that consist of iron and its native oxide. Employing nuclear resonant scattering of synchrotron radiation from {sup 57}Fe probe layers, this manifests as 1/2-order Bragg peaks in the reflectivity curve. From the field dependence of their intensity, we deduce the existence of two magnetic sublattices that are canted by an angle of almost 90 deg. and rotate as one unit in low fields. For higher fields, the two sets of moments gradually align collinear to the external field. This behavior can be explained by a coupling of two adjacent Fe layers that is mediated by an antiferromagnetic order in the oxide spacer between them.

Diederich, Thomas; Couet, Sebastien; Roehlsberger, Ralf [Hamburger Synchrotronstrahlungslabor (HASYLAB), Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, 22603 Hamburg (Germany)

2007-08-01

425

Hydrophobic spacers enhance the helicity and lectin binding of synthetic, pH-responsive glycopolypeptides.  

PubMed

The influence of different hydrophobic spacers on the structural and lectin binding properties of well-defined glycopolypeptides decorated with galactose moieties was investigated. All glycopolypeptides were prepared from a poly(?,l-glutamic acid) (PGA) precursor via a polymer-analogous aqueous amide coupling reaction. Thereby, two alkyl spacers of different length (C6 and C11) as well as an aromatic spacer were introduced between the backbone and the galactose moieties, as confirmed by (1)H NMR spectroscopy. The secondary structure was investigated as a function of the sugar density and the pH by circular dichroism (CD) spectroscopy. It was found that the helicity in acidic medium and thus the typical coil-to-helix transition is strongly enhanced by the hydrophobic spacers. Preliminary lectin binding tests via turbidimetric assay revealed that the spacers also significantly enhance the interaction of the glycopolypeptides with the lectin RCA120. PMID:25365471

Mildner, Robert; Menzel, Henning

2014-12-01

426

Modified Open-door Laminoplasty Using Hydroxyapatite Spacers and Miniplates  

PubMed Central

Objective Cervical laminoplasty has been widely accepted as one of the major treatments for cervical myelopathy and various modifications and supplementary procedures have been devised to achieve both proper decompression and stability of the cervical spine. We present the retrospectively analyzed results of a modified unilateral open-door laminoplasty using hydroxyapatite (HA) spacers and malleable titanium miniplates. Methods From June 2008 to May 2012, among patients diagnosed with cervical spondylotic myelopathy and ossification of posterior longitudinal ligament, the patients who received laminoplasty were reviewed. Clinical outcome was assessed using Frankel grade and Japanese Orthopaedic Association score. The radiologic parameters were obtained from plain films, 3-dimensional computed tomography and magnetic resonance images. Results A total of 125 cervical laminae were operated in 38 patients. 11 patients received 4-level laminoplasty and 27 patients received 3-level laminoplasty. Postoperatively, the mean Frankel grade and JOA score were significantly improved from 3.97 to 4.55 and from 12.76 to 14.63, respectively (p<0.001). Radiologically, cervical curvature was worsened from 19.09 to 15.60 (p=0.025). The percentage of range of motion preservation was 73.32±22.39%. The axial dimension of the operated spinal canal was increased from 1.75 to 2.70 cm2 (p<0.001). Conclusion In the presenting study, unilateral open-door laminoplasty using HA spacers and miniplates appears to be a safe, rapid and easy procedure to obtain an immediate and rigid stabilization of the posterior elements of the cervical spine. This modified laminoplasty method showed effective expansion of the spinal canal and favorable clinical outcomes. PMID:25346767

Jin, Sung-Won; Kim, Bum-Joon; Choi, Jong-Il; Ha, Sung-Kon; Kim, Sang-Dae; Lim, Dong-Jun

2014-01-01

427

Ten-Year Outcome of Serum Metal Ion Levels After Primary Total Hip Arthroplasty  

PubMed Central

Abstract: We previously reported on the metal ion concentrations of cobalt, chromium, and titanium that were found in the serum of patients three years after they had undergone primary total hip arthroplasty as compared with the concentrations found in the serum of control patients who did not have an implant. This study is a concise update on the serum metal levels found in a cohort of these patients ten years after the time of hip implantation. Of the original seventy-five subjects, metal ion levels were available for forty patients (53%). Ten patients (hybrid group) had received a hybrid total hip replacement that consisted of a modular cobalt-alloy femoral stem with a cobalt-alloy femoral head that had been inserted with cement and a titanium acetabular socket that had been inserted without cement. Nine patients (cobalt-chromium [CoCr] group) had received an implant with an extensively porous-coated modular cobalt-alloy femoral stem and femoral head along with a titanium acetabular socket; the femoral and acetabular components had each been inserted without cement. Eight patients (titanium group) had undergone insertion of a proximally porous-coated modular titanium-alloy femoral stem with a cobalt-alloy femoral head and a titanium acetabular socket; the femoral and acetabular components had each been inserted without cement. Thirteen patients (control group) from the original control group of patients who had not received an implant served as control subjects. Serum metal levels were measured with use of high-resolution sector field inductively coupled plasma mass spectrometry. The hybrid total hip arthroplasty group had mean cobalt levels that were 3.2 times higher at 120 months than they were at baseline, and the cobalt levels in that group were significantly higher than those in the titanium total hip arthroplasty group at thirty-six, sixty, eighty-four, ninety-six, and 120 months (p < 0.01). The hybrid group had m