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

PubMed Central

Background Outcome data on two-stage revision surgery for deep infection after septic hip arthritis are limited and inconsistent. This study presents the medium-term results of a new, standardized two-stage arthroplasty with preformed hip spacers and cementless implants in a consecutive series of adult patients with septic arthritis of the hip treated according to a same protocol. Methods Nineteen patients (20 hips) were enrolled in this prospective, non-randomized cohort study between 2000 and 2008. The first stage comprised femoral head resection, debridement, and insertion of a preformed, commercially available, antibiotic-loaded cement hip spacer. After eradication of infection, a cementless total hip arthroplasty was implanted in the second stage. Patients were assessed for infection recurrence, pain (visual analog scale [VAS]) and hip joint function (Harris Hip score). Results The mean time between first diagnosis of infection and revision surgery was 5.8 ± 9.0 months; the average duration of follow up was 56.6 (range, 24 - 104) months; all 20 hips were successfully converted to prosthesis an average 22 ± 5.1 weeks after spacer implantation. Reinfection after total hip joint replacement occurred in 1 patient. The mean VAS pain score improved from 48 (range, 35 - 84) pre-operatively to 18 (range, 0 - 38) prior to spacer removal and to 8 (range, 0 - 15) at the last follow-up assessment after prosthesis implantation. The average Harris Hip score improved from 27.5 before surgery to 61.8 between the two stages to 92.3 at the final follow-up assessment. Conclusions Satisfactory outcomes can be obtained with two-stage revision hip arthroplasty using preformed spacers and cementless implants for prosthetic hip joint infections of various etiologies.



Hip Implants  


... advances in the design, construction, and implantation of artificial hip joints, resulting in a high percentage of ... number of measurements to ensure proper prosthesis selection, limb length, and hip rotation. After making the incision, ...


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



Mechanical evaluation of unipolar hip spacer constructs.  


The strengths of 3 hip spacer constructs--Steinmann pins, a short intramedullary nail (both cement-incorporated), and a Charnley prosthesis--were determined and compared with the strength of a commercially available hip spacer. The hip prosthesis construct was more than twice as strong as the other 2 constructs and was equivalent in strength to the commercial spacer. For spacer applications in which limited weight-bearing is anticipated, the hip prosthesis construct appears more efficacious, but its pros and cons should be compared with those of the commercial product. PMID:19081880

Kummer, Frederick J; Strauss, Eric; Wright, Kevin; Kubiak, Erik N; Di Cesare, Paul E



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

PubMed Central

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

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



Preformed antibiotic-loaded cement spacers for two-stage revision of infected total hip arthroplasty. Long-term results.  


Two-stage revision is the most widely accepted and performed intervention for chronically infected hip prosthesis and different interim spacers have been proposed. In recent years, antibiotic-loaded preformed spacers have become available on the market. The aim of this retrospective study was to assess the long-term results of two-stage revision with preformed spacers and uncemented hip prosthesis for the treatment of septic hip prosthesis. From 2000 to 2010, 183 consecutive patients underwent two-stage revision of septic hip prosthesis, with a same protocol, including preformed antibiotic-loaded cement spacer and a cementless modular hip revision prosthesis and four to six weeks antibiotic administration. Clinical and radiologic assessment at a minimum follow-up of two years was performed. At a minimum two years follow-up, 10 patients (5.4%) had had an infection recurrence, four (2.2%) an aseptic loosening and four more required partial revision of the modular components of the prosthesis, because of hip instability/dislocation; 21 patients died or were lost to follow-up. Considering all the reasons for revision, survivorship at eleven years was 93.9%. Harris Hip Score improved from 29.1 ± 14.6 pre-operatively to 41.1 ± 15.9 after spacer implant and 81.7 ± 17.6 after hip revision. The main complications after spacer implant included: spacer dislocation (16.4%), intra-operative femoral fractures (2.7%), and thromboembolism (2.1%). Complications after hip revision were: instability/dislocation (4,3%), intra-operative femoral fractures (1.6%), and thromboembolism (3.3%). Two-stage revision of septic hip prosthesis with preformed antibiotic-loaded spacers and cementless hip prosthesis provides satisfactory long-term results, with reduced complications. PMID:22956370

Romanò, Carlo L; Romanò, Delia; Albisetti, Alessandra; Meani, Enzo


Two-stage cementless revision of late total hip arthroplasty infection using a premanufactured spacer.  


We observed 44 patients with 2-stage revisions for septic hip prostheses. We used a uniform protocol consisting of the implantation of a preformed spacer (interval 12-26 weeks), specific systemic antibiotic therapies, and cementless total hip arthroplasty at time of reimplantation. The minimum follow-up was 36 months (mean, 67 months; range, 36-120 months). During the spacer period, we observed 4 dislocations and 2 fractures leading to a resection arthroplasty interval before reimplantation in 5 cases. In one patient, reinfection was diagnosed 12 months after reimplantation. The Harris hip score increased from a preoperative mean of 39 to 90 at a mean follow-up of 67 months after reimplantation. PMID:22177795

Neumann, Daniel R P; Hofstaedter, Thomas; List, Corina; Dorn, Ulrich



Instrumented hip implants: Electric supply systems.  


Instrumented hip implants were proposed as a method to monitor and predict the biomechanical and thermal environment surrounding such implants. Nowadays, they are being developed as active implants with the ability to prevent failures by loosening. The generation of electric energy to power active mechanisms of instrumented hip implants remains a question. Instrumented implants cannot be implemented without effective electric power systems. This paper surveys the power supply systems of seventeen implant architectures already implanted in-vivo, namely from instrumented hip joint replacements and instrumented fracture stabilizers. Only inductive power links and batteries were used in-vivo to power the implants. The energy harvesting systems, which were already designed to power instrumented hip implants, were also analyzed focusing their potential to overcome the disadvantages of both inductive-based and battery-based power supply systems. From comparative and critical analyses of the methods to power instrumented implants, one can conclude that: inductive powering and batteries constrain the full operation of instrumented implants; motion-driven electromagnetic energy harvesting is a promising method to power instrumented passive and active hip implants. PMID:24050511

Soares Dos Santos, Marco P; Ferreira, Jorge A F; Ramos, A; Simões, José A O; Morais, Raul; Silva, Nuno M; Santos, Paulo M; Reis, M J C S; Oliveira, T



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.

Sandri, Andrea; Samaila, Elena; Magnan, Bruno



Navigated cup implantation in hip arthroplasty  

PubMed Central

Background and purpose Many studies have suggested that navigation-based implantation can improve cup positioning in total hip arthroplasty (THA). We conducted a systematic review and meta-analysis to compile the best available evidence, and to overcome potential shortcomings because of small sample sizes in individual studies. Methods The search strategy covered the major medical databases from January 1976 through August 2007, as well as various publishers' databases. The internal validity of individual studies was evaluated independently by 3 reviewers. We used random-effects modeling to obtain mean differences in cup angulation and relative risk (RR) of cup positioning outside Lewinnek's safe zone. Results Of 363 citations originally identified, 5 trials of moderate methodology enrolling a total of 400 patients were included in the analysis. Mean cup inclination and anteversion were not statistically significantly different between the conventional groups and the navigated groups. Navigation reduced the variability in cup positioning and the risk of placing the acetabular component beyond the safe zone (RR = 0.21, CI: 0.13–0.32). Interpretation Based on the current literature, navigation is a reliable tool to optimize cup placement, and to minimize outliers. However, long-term outcomes and cost utility analyses are needed before conclusive statements can be drawn about the value of routine navigation in THA.



HipNav: Preoperative Planning and Intra-operative Navigational Guidance for Acetabular Implant Placement in Total Hip Replacement Surgery  

Microsoft Academic Search

The Hip Navigation or HipNav system allows a surgeon to determine optimal, patient-specific acetabular implant placement, and accurately achieve the desired acetabular implant placement during surgery. Hip- Nav includes three components: a pre-operative planner, a range of motion simulator, and an intra-oper- ative tracking and guidance system. The goals of the current HipNav system are to: I) reduce dislocations following

A. M. DiGioia; D. A. Simon; B. Jarama; M. Blackwel; E Morgan; R. V. O'Toole; B. Colgan; E. Kischel


Improvement of the reliability of ceramic hip joint implants  

Microsoft Academic Search

The aim of this article is to present the optimization of a proof test procedure of ceramic hip joint ball heads. The proof test rejects defective samples in the production line before being implanted into human body. Thereby on every ceramic ball head a static load is applied, which is somewhat higher than the maximum physiological load. The magnitude of

Bernhard Weisse; Marcel Zahner; W. Weber; W. Rieger



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.

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



Successful treatment of Candida albicans-infected total hip prosthesis with staged procedure using an antifungal-loaded cement spacer.  


We present a rare case of an immunocompetent host who developed a Candida albicans-infected total hip prosthesis. The infection could not be eradicated with debridement and extensive antifungal therapy. Our patient first underwent a resection of the proximal femur and local treatment with gentamicin-loaded cement beads. In a second procedure, a handmade cement spacer impregnated with voriconazole, amphotericin B, and vancomycin was placed. After 3 months of additional systemic antibiotic therapy, the patient remained afebrile, and a tumor prosthesis was placed. Six years postoperatively, she is doing well, walking with a small limp and no signs of recurrent infection. This is the first report on elution of voriconazole and amphotericin B from bone cement delivered at clinically significant concentrations for at least 72 hours. PMID:22810009

Deelstra, Jenneke J; Neut, Danielle; Jutte, Paul C



Revision total hip arthroplasty: the femoral side using cemented implants.  


Advances in surgical technique and implant technology have improved the ten-year survival after primary total hip arthroplasty (THA). Despite this, the number of revision procedures has been increasing in recent years, a trend which is predicted to continue into the future. Revision THA is a technically demanding procedure often complicated by a loss of host bone stock which may be compounded by the need to remove primary implants. Both cemented and uncemented implant designs are commonly used in the United Kingdom for primary and revision THA and much controversy still exists as to the ideal method of stem fixation. In this article we discuss revision of the femur using cemented components during revision THA. We focus on three clinical scenarios including femoral cement-in-cement revision where the primary femoral cement-bone interface remains well fixed, femoral cement-in-cement revision for peri-prosthetic femoral fractures, and femoral impaction grafting. We discuss the clinical indications, surgical techniques and clinical outcomes for each of these procedures. PMID:21165618

Holt, Graeme; Hook, Samantha; Hubble, Matthew



Revision total hip arthroplasty: the femoral side using cemented implants  

PubMed Central

Advances in surgical technique and implant technology have improved the ten-year survival after primary total hip arthroplasty (THA). Despite this, the number of revision procedures has been increasing in recent years, a trend which is predicted to continue into the future. Revision THA is a technically demanding procedure often complicated by a loss of host bone stock which may be compounded by the need to remove primary implants. Both cemented and uncemented implant designs are commonly used in the United Kingdom for primary and revision THA and much controversy still exists as to the ideal method of stem fixation. In this article we discuss revision of the femur using cemented components during revision THA. We focus on three clinical scenarios including femoral cement-in-cement revision where the primary femoral cement-bone interface remains well fixed, femoral cement-in-cement revision for peri-prosthetic femoral fractures, and femoral impaction grafting. We discuss the clinical indications, surgical techniques and clinical outcomes for each of these procedures.

Hook, Samantha; Hubble, Matthew



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


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

Beulah, Pearline; Sivarasu, Sudesh; Mathew, Lazar



Implant materials for hip endoprostheses: old proofs and new trends  

Microsoft Academic Search

To judge the significance of a hip joint replacement, the clinical results over 10–20 years must be evaluated. Today, still over half of all hip endoprostheses involves cement fixation. The rest is uncemented, in direct contact with bone. Total hip prostheses with polyethylene cups are equipped either with cobalt-, iron-, surface-hardened titanium-based metal or Al2O3 ceramic ball heads. The pairing

M. Semlitsch; H.-G. Willert



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



Ceramic\\/Ceramic Total Hip Replacement: The American Experience with Stryker Implants  

Microsoft Academic Search

\\u000a A major challenge for total hip arthroplasty is to minimize wear and osteolysis in young, active patients. Alumina ceramic\\u000a bearings have shown superior wear resistance and lubrication and do not carry the risk of ion release. In a prospective randomized\\u000a study (ABC), 514 hips were implanted. All patients (average age, 53 years) received the same press-fit hydroxyapatite coated\\u000a femoral stem;

B. E. Bierbaum; J. D’Antonio; W. Capello; M. Manley; R. Deshmukh


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.

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



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


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



Reproducibility of radiographic assessment of femoral implant position after hip resurfacing arthroplasty: a pilot study.  


To determine whether femoral implant position can be reproducibly measured on plain digital radiographs, we prospectively studied 40 patients after hip resurfacing arthroplasty. Three observers performed double blinded randomized analysis of calibrated digital radiographs meeting strict quality criteria. The implant stem-shaft angle and femoral anteversion angle were measured by the trapezoid method of axis determination using OsiriX software. The upper and lower offset and the anterior and posterior offset were measured. The statistical analysis was performed using Pearson correlation tests (intra-observer reproducibility) and Fisher F tests (inter-observer reproducibility). Intra-observer reproducibility was very good for all parameters and all observers. Inter-observer reproducibility was excellent except for superior offset measurement. Thus, this study validates a radiographic method for assessing the femoral implant position in hip resurfacing. We believe this could be useful for future studies on hip resurfacing devices. PMID:23558663

Pailhé, Régis; Reina, Nicolas; Ancelin, David; Cavaignac, Etienne; Maubisson, Laurent; Sharma, Akash; Chiron, Philippe



Intervertebral spacer as an adjunct to anterior lumbar fusion. Part II. Six-month implantation in baboons.  


Failure of interbody fusions in the lumbar spine are common due to reliance on the graft for structural support during healing by creeping substitution. Support of the interspace with an implant should result in improved fusion success. The objective of this study was to evaluate the stability of the implant in vivo and its potential as an adjunct to promote interbody arthrodesis. Prototype 3, a porous coated intervertebral spacer with extension lugs made of Ti-6A1-4V, was implanted vertically between adjacent lumbar vertebrae anteriorly in four baboons undergoing anterior interbody fusion. The animals were allowed freedom of activity for 6 months before being killed. A transperitoneal approach was made exposing the L4-L5 or L5-L6 interspace. At time of killing, clinical evaluation of the implant-vertebral body construct showed stability to manual stresses applied in extension, flexion, and rotation. Serial radiographs taken during the 6 months of implantation showed no change in position or displacement of the implants. Axial and torsional cyclic loads were applied to each spine at 1 cycle/s for 20,000 cycles. Statistical analysis of the motion profiles for intact and implanted spines demonstrated no significant difference in axial or rotational displacements at the arthrodesis level or adjacent unoperated levels, L1 and L4. The in vivo 6-month study in baboons confirmed implant stability and maintenance of disc space height. Variable osseous healing was noted. Release of plasma spray beading may have resulted from improper application on the implant or micromotion within the construct. A better method to mechanically interlock the plungers is being studied. Clinical trials based on this work appear justified. PMID:9588470

Nasca, R J; Montgomery, R D; Moeini, S M; Lemons, J E



Appendix A: Hip Implant Device Utilization in the U  

Center for Biologics Evaluation and Research (CBER)

Text Version... systems compared to all other available bearing type THR systems. ... received for hip resurfacing systems of different bearing types as none ... More results from


Implant materials for hip endoprostheses: old proofs and new trends.  


To judge the significance of a hip joint replacement, the clinical results over 10-20 years must be evaluated. Today, still over half of all hip endoprostheses involves cement fixation. The rest is uncemented, in direct contact with bone. Total hip prostheses with polyethylene cups are equipped either with cobalt-, iron-, surface-hardened titanium-based metal or Al2O3 ceramic ball heads. The pairing Al2O3/Al2O3 and CoCrMoC metal/metal for cups and balls are extremely wear resistant. Most of the cementless cups have spherical or conical cobalt- or titanium-based metal shells with inserts made of polyethylene or CoCrMoC metal. For the fixation stems, high-strength iron-, cobalt- or titanium-based wrought metals are preferred. A taper spigot connection between metallic or ceramic ball heads and stems allows a modular design of hip joint replacements. We have learnt much from the mistakes of the last 40 years in hip endoprosthetics, and there is no excuse to repeat them again. PMID:7734234

Semlitsch, M; Willert, H G



The Otto Aufranc Award. Wear and lubrication of metal-on-metal hip implants.  


The implication of polyethylene wear particles as the dominant cause of periprosthetic osteolysis has created a resurgence of interest in metal-on-metal implants for total hip arthroplasty because of their potential for improved wear performance. Twenty-two cobalt chromium molybdenum metal-on-metal implants were custom-manufactured and tested in a hip simulator. Accelerated wear occurred within the first million cycles followed by a marked decrease in wear rate to low steady-state values. The volumetric wear at 3 million cycles was very small, ranging from 0.15 to 2.56 mm3 for all implants tested. Larger head-cup clearance and increased surface roughness were associated with increased wear. Independent effects on wear of material processing (wrought, cast) and carbon content were not identified. Implant wear decreased with increasing lambda ratio, a parameter used to relate lubricant film thickness to surface roughness, suggesting some degree of fluid film lubrication during testing. This study provided important insight into the design and engineering parameters that affect the wear behavior of metal-on-metal hip implants and indicated that high quality manufacturing can reproducibly lead to very low wear. PMID:10611857

Chan, F W; Bobyn, J D; Medley, J B; Krygier, J J; Tanzer, M



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.



Maintenance of bone mineral density after implantation of a femoral neck hip prosthesis  

PubMed Central

Background Stress shielding of the proximal femur has been observed in a number of conventional cementless implants used in total hip arthroplasty. Short femoral-neck implants are claiming less interference with the biomechanics of the proximal femur. The goal of this study was to investigate the changes of bone-mineral density in the proximal femur and the clinical outcome after implantation of a short femoral-neck prosthesis. Methods We prospectively assessed the clinical outcome and the changes of bone mineral density of the proximal femur up to one year after implantation of a short femoral neck prosthesis in 20 patients with a mean age of 47 years (range 17 to 65). Clinical outcome was assessed using the Harris Hip Score. The WOMAC was used as a patient-relevant outcome-measure. The bone mineral density was determined using dual energy x-ray absorptiometry, performed 10 days, three months and 12 months after surgery. Results The Harris Hip Score improved from an average preoperative score of 46 to a postoperative score at 12 months of 89 points, the global WOMAC index from 5,3 preoperatively to 0,8 at 12 months postoperatively. In contrast to conventional implants, the DEXA-scans overall revealed a slight increase of bone mineral density in the proximal femur in the 12 months following the implantation. Conclusion The short femoral neck stem lead to a distinct bone reaction. This was significantly different when compared to the changes in bone mineral density reported after implantation of conventional implants.

Decking, Ralf; Rokahr, Christoph; Zurstegge, Matthias; Simon, Ulrich; Decking, Jens



Rationale, design and clinical performance of the Superion® Interspinous Spacer: a minimally invasive implant for treatment of lumbar spinal stenosis.  


Lumbar spinal stenosis is a progressive degenerative condition that manifests as low back pain with neurogenic claudication as a cardinal clinical feature. Although mild radicular symptoms can often be successfully treated with conservative care, management of lumbar spinal stenosis grows increasingly difficult as symptoms worsen. No satisfactory nonsurgical treatments exist to manage moderate radicular symptoms and, therefore, these patients are faced with the decision of continuing ineffective conservative options or opting to undergo invasive decompressive spine surgery. The Superion(®) Interspinous Spacer (Vertiflex, Inc., CA, USA) was developed specifically to fill the therapeutic void between conservative care and surgical decompression. The Superion device is a titanium implant that is delivered percutaneously and deployed between the spinous processes at the symptomatic vertebral levels. The Superion device improves radicular symptoms by limiting spinal extension and, consequently, minimizing impingement of neural and vascular elements. This article describes the rationale for and the design of the Superion device and summarizes initial clinical results with this novel, minimally invasive interspinous spacer. PMID:21728727

Loguidice, Vito; Bini, Walter; Shabat, Shay; Miller, Larry E; Block, Jon E



The fully hydroxyapatite-coated total hip implant  

Microsoft Academic Search

The clinical and roentgenographic results of 54 fully hydroxyapatite (HA)-coated primary total hip arthroplasties in 45 patients was studied. Both the femoral and the acetabular components had a 200-?m coating of hydroxyapatite. The mean age of the patients was 54.8 years. Twenty-three patients were between 45 and 60 years of age. There were 24 men and 21 women. Nine patients

Ravishankar Vedantam; C. Ruddlesdin



Validation of a computer navigation system and a CT method for determination of the orientation of implanted acetabular cup in total hip arthroplasty: A cadaver study  

Microsoft Academic Search

BackgroundSuccessful hip reconstruction to restore the normal hip biomechanics requires precise placement of implants. Computer assisted navigation in total hip arthroplasty has been proposed to have the potential to help achieve a high accuracy in implant placement. The goal of the study was to evaluate the accuracy of an imageless computer navigation system on cadavers and to validate a non-invasive

Fang Lin; Dohyung Lim; Richard L. Wixson; Steven Milos; Ronald W. Hendrix; Mohsen Makhsous



Wear rates of ceramic-on-ceramic bearing surfaces in total hip implants: A 12-year follow-up study  

Microsoft Academic Search

A retrospective clinical and radiographic analysis was performed on 58 patients (60 hips; mean age at time of surgery, 45.2 years) at a minimum of 10-year follow-up (mean, 12.7 years) after total hip replacement using a ceramic-on-ceramic bearing total hip implant (Autophor, Smith and Nephew, Memphis, TN). Mean wear rate at final follow-up was 0.21 mm, averaging 0.016 mm\\/y. There

Laith M. Jazrawi; Eric Bogner; Craig J. Della Valle; Frank S. Chen; Kevin I. Pak; Steven A. Stuchin; Victor H. Frankel; Paul E. Di Cesare



Wear particles from metal-on-metal total hip replacements: effects of implant design and implantation time.  


Detailed characterization of wear particles is necessary to understand better the implant wear mechanisms and the periprosthetic tissue response. The purposes of the present study were to compare particle characteristics of current with older designs of metal-on-metal (MM) total hip replacements (THRs), and to determine the effect of implantation time on wear particle characteristics. Metal wear particles isolated from periprosthetic tissues from 19 patients with MM THRs of current and older designs and at different implantation times (very short, longer, and very long) were studied using transmission electron microscopy and energy dispersive X-ray analysis. The particles from the current design implants with implantation times of not more than 15 months (very short-term) were almost exclusively round to oval chromium oxide particles. In all other cases, although the predominance was still round to oval chromium oxide particles, greater proportions of cobalt-chromium-molybdenum (Co-Cr-Mo) particles, mainly needle-shaped, were detected. Very long-term THRs implanted for more than 20 years had the highest percentage of needle-shaped Co-Cr-Mo particles. Particle lengths were not markedly different between the different designs and implantation times except for the current design implants of not more than 15 months, which had a significantly smaller mean length of 39 nm. In conclusion, the implant design did not seem to have a significant influence on particle characteristics whereas the implantation time appeared to have the most effect on the particles. It should be noted that, because of the limited number of tissue retrievals available, some uncertainty remains regarding the generality of these findings. PMID:16669387

Catelas, I; Campbell, P A; Bobyn, J D; Medley, J B; Huk, O L



Primary and long-term stability of a short-stem hip implant.  


The new generation short-stem hip implants are designed to encourage physiological-like loading, to minimize stress-strain shielding and therefore implant loosening in the long term. As yet there are no long-term clinical studies available to prove the benefits of these short-stem implants. Owing to this lack of clinical data, numerical simulation may be used as a predictor of longer term behaviour. This finite element study predicted both the primary stability and long-term stability of a short-stem implant. The primary implant stability was evaluated in terms of interface micromotion. This study found primary stability to fall within the critical threshold for osseointegration to occur. Longer term stability was evaluated using a strain-adaptive bone remodelling algorithm to predict the long-term behaviour of the bone in terms of bone mineral density (BMD) changes. No BMD loss was observed in the classical Gruen zones 1 and 7 and bone remodelling patterns were comparable with hip resurfacing results in the literature. PMID:21053775

Dabirrahmani, D; Hogg, M; Kohan, L; Gillies, M



Comparison of alloys and designs in a hip simulator study of metal on metal implants.  


Previous studies of metal on metal hip implants have shown that it is possible to obtain substantially lower volumetric wear than with metal on polyethylene pairings. To work toward design optimization, the gravimetric wear of serum lubricated, metal on metal implants was examined in a hip simulator apparatus. Seventeen implant specimens were fabricated from 3 alloys in various combinations of diameter and clearance and wear tested as many as 3 million cycles. Theory was developed to predict the thickness of elastohydrodynamic lubricant films, the linear wear, and wear zone geometry. To help interpret the data, implant diameter and clearance were combined into a single parameter called effective radius. Implants with larger effective radii (6-11 m) tended to experience lower wear, and theory suggested that this was a result of the correspondingly thicker elastohydrodynamic lubricant films providing an enhanced mixed film lubrication. As in most wear testing, the results were scattered but, overall, a low carbon, wrought alloy had lower wear than either a high carbon, cast alloy or a low carbon, commercial alloy. Because of the small number of specimens tested and possible variations in tribologic parameters such as calcium phosphate film formation and surface microgeometry, there was low statistical reliability of the results. PMID:8769332

Medley, J B; Chan, F W; Krygier, J J; Bobyn, J D



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.



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


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

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



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.

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



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


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

Cuckler, J M



The fully hydroxyapatite-coated total hip implant. Clinical and roentgenographic results.  


The clinical and roentgenographic results of 54 fully hydroxyapatite (HA)-coated primary total hip arthroplasties in 45 patients was studied. Both the femoral and the acetabular components had a 200-microns coating of hydroxyapatite. The mean age of the patients was 54.8 years. Twenty-three patients were between 45 and 60 years of age. There were 24 men and 21 women. Nine patients under-went bilateral operations. The average follow-up period was 46.9 months (range, 24-78 months). The average preoperative Harris hip score was 48, and the average postoperative Harris hip score was 94 at 1 year and 96 at 2 years. Revision surgery for component loosening and infection was carried out in four (7.4%) cases. There was aseptic loosening of the femoral component in one case (1.85%) and of the acetabular component in two cases (3.7%). Roentgenographic evaluation indicated that greater stress transfer occurs in the distal two thirds of the femoral stem. Proximomedial femoral neck resorption was noted in 23 cases (57.4%). Excellent to good clinical outcome was obtained in 89% of patients. In the short term, the rate of aseptic loosening of the fully HA-coated hip prosthesis in our series is higher than the reported rates of aseptic loosening of proximally HA-coated total hip implants. Controlled clinical studies would be required to evaluate the relative efficacy of the fully HA-coated and the proximally HA-coated hip prostheses. PMID:8872572

Vedantam, R; Ruddlesdin, C



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


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

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



[15-year results following implantation of a stem type AML hip prosthesis].  


The trend in arthroplasty of the hip joint to implement new models is partly based on theoretical considerations. In order to verify to which extent the philosophy of individual models is ultimately successful, the presentation of long-term results is required. In the years 1991 and 1992, 433 patients with primary implantation of an uncemented total hip replacement in primary coxarthrosis with a stem type AML (anatomic medullary locking) were treated surgically. 283 of them got a cementless cup type Duraloc. In 311 (71.8 %) patients the mean survival rate of the prosthesis could be determined at a mean follow-up of 15.5 years. 145 (33.5 %) patients were followed up completely both clinically and radiologically. Radiographically, the stem position, changes of the periprosthetic bone of the stem and the cup, as well as the wear of the cups were examined. The cumulative survival rate of the AML stem after 15.5 years was 97.5 %, of the Duraloc cup 88.2 %. The clinical results of the hip scores according to Harris and Merle d'Aubigné were good and excellent and patient satisfaction was very high. There was no relationship between stem position, stress shielding and surrounding lyses at the femur and the acetabulum and survival of stem or cup. There was no correlation between inlay wear and survival of the Duraloc cup. A subsiding of the stem in 2 cases had no effect on the clinical symptoms and quality of life. The press-fit implanted AML stem and the Duraloc cup revealed very good results during the investigation period. Like other implants, the survival rate is limited at the presented implant mainly by the cup. PMID:23696163

Schwerter, K; Meyenberg, A; Sander, K; Layher, F; Roth, A



Sub0.1 ?m CMOS with source\\/drain extension spacer formed using nitrogen implantation prior to thick gate re-oxidation  

Microsoft Academic Search

Source\\/drain (S\\/D) extensions with low Rs and low Cgd are required for high performance CMOS. In this work, we report on a new process whereby an extension spacer is formed after gate etch using a blanket nitrogen ion implantation (N I\\/I) prior to thick gate reoxidation (GROX). The new process reduces n, pMOS Cgd by 12% and 20%, respectively and

J. C. Hu; A. Chatterjee; M. Mehrotra; J. Xu; W.-T. Shiau; M. Rodder



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

NASA Astrophysics Data System (ADS)

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

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



Mesh morphing for finite element analysis of implant positioning in cementless total hip replacements.  


Finite element (FE) analysis of the effect of implant positioning on the performance of cementless total hip replacements (THRs) requires the generation of multiple meshes to account for positioning variability. This process can be labour intensive and time consuming as CAD operations are needed each time a specific orientation is to be analysed. In the present work, a mesh morphing technique is developed to automate the model generation process. The volume mesh of a baseline femur with the implant in a nominal position is deformed as the prosthesis location is varied. A virtual deformation field, obtained by solving a linear elasticity problem with appropriate boundary conditions, is applied. The effectiveness of the technique is evaluated using two metrics: the percentages of morphed elements exceeding an aspect ratio of 20 and an angle of 165 degrees between the adjacent edges of each tetrahedron. Results show that for 100 different implant positions, the first and second metrics never exceed 3% and 3.5%, respectively. To further validate the proposed technique, FE contact analyses are conducted using three selected morphed models to predict the strain distribution in the bone and the implant micromotion under joint and muscle loading. The entire bone strain distribution is well captured and both percentages of bone volume with strain exceeding 0.7% and bone average strains are accurately computed. The results generated from the morphed mesh models correlate well with those for models generated from scratch, increasing confidence in the methodology. This morphing technique forms an accurate and efficient basis for FE based implant orientation and stability analysis of cementless hip replacements. PMID:19744873

Bah, Mamadou T; Nair, Prasanth B; Browne, Martin



Surface Changes to Alumina Femoral Heads after Metal Staining during Implantation, and after Recurrent Dislocations of the Prosthetic Hip  

Microsoft Academic Search

Metal staining of alumina ceramic femoral heads can occur during implantation of total hip components and during reduction\\u000a of a dislocated total hip. To determine whether or not such staining results in surface damage to alumina ceramic femoral\\u000a heads in vivo, we examined two groups of explanted femoral heads. Group 1 consisted of four femoral heads with surface metal\\u000a staining

B. S. Bal; M. N. Rahaman; T. Aleto; F. S. Miller; F. Traina; A. Toni


The osseous response to corundum blasted implant surfaces in a canine hip model.  


The purpose of this study was to examine the radiographic and histologic response to corundum blasted implant surfaces of varying roughness in a canine total hip arthroplasty model. Three types of tapered femoral implants were made from titanium alloy and were identical in every respect except surface finish. The entire surface of the femoral implant had a 2.9-, 4.2-, or 6.7-micron average surface roughness (Ra) from blasting with 60-, 24-, or 16-grit corundum particles, respectively. Twenty-two stems in 11 dogs were evaluated at 6 months. Twenty-one of the stems showed osseointegration, whereas in one stem a fibrous interface developed. Abundant new periimplant bone formation occurred, particularly within the intramedullary canal where trabeculae spanned implant to endosteal cortex gaps as large as 5 mm. Bone apposition with the 60-, 24-, and 16-grit stems averaged 31.7%, 32%, and 27.9%, respectively; the differences were not statistically significant. However, the pattern of new bone formation was different in that the average length of each region of bone apposition for the 60- and 24-grit surfaces was 50% greater than that for the coarser 16-grit surface. The observations of this study indicate that because of their highly osteoconductive nature, corundum blasted surfaces represent an important and valuable technology for the design of noncemented implants. PMID:10416415

Hacking, S A; Bobyn, J D; Tanzer, M; Krygier, J J



Outcome and serum ion determination up to 11 years after implantation of a cemented metal-on-metal hip prosthesis  

PubMed Central

Background and purpose Little is known about the long-term outcome of cemented metal-on-metal hip arthroplasties. We evaluated a consecutive series of metal-on-metal polyethylene-backed cemented hip arthroplasties implanted in patients under 60 years of age. Methods 109 patients (134 joint replacements) were followed prospectively for mean 9 (7–11) years. The evaluation included clinical score, radiographic assessment, and blood sampling for ion level determination. Results At the final review, 12 hips had been revised, mainly because of aseptic loosening of the socket. Using revision for aseptic loosening as the endpoint, the survival rate at 9 years was 91% for the cup and 99% for the stem. In addition, 35 hips showed radiolucent lines at the bone-cement interface of the acetabulum and some were associated with osteolysis. The median serum cobalt and chromium levels were relatively constant over time, and were much higher than the detection level throughout the study period. The cobalt level was 1.5 ?g/L 1 year after implantation, and 1.44 ?g/L 9 years after implantation. Interpretation Revisions for aseptic loosening and radiographic findings in the sockets led us to halt metal-on-metal-backed polyethylene cemented hip arthroplasty procedures. If the rigidity of the cemented socket is a reason for loosening, excessive release of metal ions and particles may be involved. Further investigations are required to confirm this hypothesis and to determine whether subluxation, microseparation, and hypersensitivity also play a role.

Lazennec, Jean-Yves; Poupon, Joel; Rousseau, Marc-Antoine; Roy, Carine; Ravaud, Philippe; Catonne, Yves



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

Microsoft Academic Search

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

Thomas M Grupp; Thomas Weik; Wilhelm Bloemer; Hanns-Peter Knaebel



Revision of late periprosthetic infections of total hip endoprostheses: pros and cons of different concepts  

Microsoft Academic Search

Many concepts have been devised for the treatment of late periprosthetic infections of total hip prostheses. A two-stage revision with a temporary antibiotic-impregnated cement spacer and a cemented prosthesis appears to be the most preferred procedure although, in recent times, there seems to be a trend towards cementless implants and a shorter period of anti- biotic treatment. Because of the

Bernd Fink


Uncemented total hip arthroplasty using the CLS stem: a titanium alloy implant with a corundum blast finish. Results at a mean 6 years in a prospective study.  


An uncemented titanium alloy stem with a corundum blast finish and an uncemented titanium fibermetal mesh socket were implanted in a series of 57 hips. These prostheses were selected for use in the youngest, most active, and/or heaviest candidates for total hip arthroplasty. Fifty hips were available for study at a minimum 60 months. At a mean 6 years, 92% of the hips were rated good or excellent. The mean Harris hip score was 92. One patient experienced mild thigh pain. The corundum blast finish was associated with reliable implant stability. Survival analysis predicted a 96% rate of implant survival at 92 months. Loss of bone density was rated mild, minimal, or none in 88% of the hips. Three hips developed severe bone loss due to systemic disease. Polyethylene wear was measurable in 86% of the hips. Twenty hips developed focal proximal femoral bone erosions. One hip had endosteal cavitation distal to zone 7. The presence of proximal femoral erosions or endosteal cavitation correlated positively with the presence of measurable polyethylene wear. The limited and proximal distribution of femoral bone erosion despite evidence of extensive polyethylene wear suggested that bone apposition to the corundum blast finish resulted in a barrier to migration of wear debris. PMID:8713908

Robinson, R P; Deysine, G R; Green, T M



Engineering issues and wear performance of metal on metal hip implants.  


A major concern in total hip arthroplasty is the generation of polyethylene wear particles at the articulating surfaces and resulting macrophage mediated periimplant osteolysis. There is renewed interest in metal on metal bearings as a solution to this problem in view of their potential for greatly improved wear performance. Using a commercially available hip simulator, the wear performance of metal on metal femoral head and acetabular cup combinations was evaluated and various parameters affecting metal on metal implant wear were identified. Nine implants custom manufactured from 2 medical grades of CoCrMo alloy (ASTM F1537-95 and F75-92) were tested within bovine serum as the lubricant to 3 million cycles (equivalent to approximately 3 years of service in vivo). The progressive wear of the components was determined by gravimetric methods at approximately every 300,000 cycles. The wear rates were characterized by an initial period of accelerated wear after which a lower steady state wear rate was observed for subsequent cycles. The presence of calcium phosphate films on the component surfaces, the microstructure of the lower carbon, wrought alloy, and increased effective radii (decreased diametral clearances) were identified as factors that may be favorable to improved wear performance. The extent of the effect on wear of each parameter, however, cannot be discerned at this point and necessitates a study in which parametric changes are more tightly controlled. The present study suggests that the use of metal on metal articulating surfaces may mitigate the problem of osteolysis by offering improved wear performance. PMID:8981885

Chan, F W; Bobyn, J D; Medley, J B; Krygier, J J; Yue, S; Tanzer, M



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


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

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



Investigation of stress shielding around the Stryker Omnifit and Exeter periprosthetic hip implants using an irreversible thermodynamic-based model.  


This study investigates stress shielding by predicting bone density around two different implants following total hip arthroplasty using a new thermodynamic-based model for bone remodeling. This model is based on chemical kinetics and irreversible thermodynamics in which bone is treated as a self-organizing system capable of exchanging matter, energy, and entropy with its surroundings. Unlike the previous works in which mechanical loading is regarded as the only stimulus for bone remodeling, this model establishes a coupling between mechanical loading and the chemical reactions involved in the process of bone remodeling. This model is incorporated into the finite element software ANSYS by means of a macro to investigate stress shielding around two different implants: Stryker Omnifit and Exeter periprosthetic hip stems. The results of the simulation showing bone density reductions of 17% in Gruen zone 1 and 27% in Gruen zones 7 around the Omnifit hip stem agree well with dual-energy X-ray absorptiometry (DEXA) measurements reported in the literature. On the other hand, the Exeter implant is found to result in more severe resorption in the proximal femur. This is consistent with clinical studies, which report a higher survivorship rate for HA-coated Omnifit hip stems. PMID:22121059

Sayyidmousavi, Alireza; Bougherara, Habiba



Subsurface changes of a MoM hip implant below different contact zones.  


Metal-on-metal hip arthroplasties undergo distinct release of toxic metal particles and ions. Thus, it is necessary to minimize this. In order to evaluate the wear behaviour of metal-on-metal hip replacements it is essential to understand the micro-structural changes in the sub-surface region. Previous studies revealed that cobalt chromium metal-on-metal implants are able to alter their mechanical behaviour by adjusting the microstructure to load. The reason for this is the so-called mechanical mixing. This means that a nano-crystal layer is formed by rotating clusters of atoms that incorporate denatured proteins from the interfacial medium. This is followed by a layer of rhombic shaped nano-crystals in between sheared epsilon-martensite lathes, twins, and stacking faults. Although the primary wear zone has been well characterized, the sub-surface structure of the stripe wear and the non-contact zone of the hip ball have yet to be analysed. For this study a 28-mm cobalt base alloy femoral head and acetabular cup were analysed. The implant was simulator tested for 5 million cycles with the application of micro-separation resulting in a clearly visible stripe wear appearance. The TEM micrograph of the primary wear zone of the ball confirmed the presence of a sub-surface layer of nano-crystals. The thickness of this layer was approximately 200 nm and the average grain diameter ranged from 35 to 40 nm. Within the stripe wear zone the micrographs also revealed a nano-crystal layer but with a thickness of only 50 nm and an average grain diameter from 15 to 20 nm. The carbon and oxygen content was highest closest to the surface which proves the occurrence of mechanical mixing. The non-contact zone of the ball was analysed as well. When compared to the primary wear zone a nano-crystal layer with similar thickness but with an average grain diameter smaller than 15 nm was observed. PMID:19627822

Pourzal, Robin; Theissmann, Ralf; Williams, Sophie; Gleising, Birgit; Fisher, John; Fischer, Alfons



Is a helical shaped implant a superior alternative to the Dynamic Hip Screw for unstable femoral neck fractures? A biomechanical investigation  

Microsoft Academic Search

BackgroundThe Dynamic Hip Screw is well established for the treatment of femoral neck fractures. However, cut-out occurs in 1–6% of all cases. This study compared the biomechanical performance of a helical shaped implant (DHS-Blade) to the Dynamic Hip Screw in an unstable femoral neck fracture model.

Markus Windolf; Volker Braunstein; Christof Dutoit; Karsten Schwieger



Kinematics of the MATCO hip simulator and issues related to wear testing of metal-metal implants.  


Metal-metal hip implants have been used clinically in Europe to reduce the risk of wear particle induced osteolysis. Joint simulator devices could provide useful information for design improvement of the modern generation of metal-metal hip implants. Early wear results for metal-metal hip specimens were obtained using a MATCO hip simulator. A detailed kinematic analysis was developed for the MATCO simulator and applied to two of the wear experiments to predict the starting surface motion, contact zone and lubricant film thickness. It was shown that points on cup surfaces were not subjected to a reciprocating interaction with the head during wear at the beginning of testing but as wear proceeded, it was suggested that, in some cases, reciprocating interaction did occur on the cup surface. Comparison between simulator and in vivo kinematics suggested a more realistic representation for cup than for head wear. In the simulator, the Hertzian contact zone moved in a circular path over the cup surface and changed in size in correspondence with the applied load. Elastohydrodynamic lubrication was considered to be possible in the simulator, with estimated fluid film thickness as great as 0.1 micron. However, such thick films were not likely to have occurred at the start of the two wear tests which were examined in detail, although some mixed film lubrication might have accounted for the relatively low wear of one of the specimens. The inclusion of kinematic details, contact mechanics and elastohydrodynamic lubrication analysis in simulator testing protocols and in design of metal metal hip implants was recommended. PMID:9141894

Medley, J B; Krygier, J J; Bobyn, J D; Chan, F W; Lippincott, A; Tanzer, M



Interspinous spacer implant in patients with lumbar spinal stenosis: preliminary results of a multicenter, randomized, controlled trial.  


A prospective, randomized, controlled trial was conducted to compare clinical outcomes in patients treated with an investigational interspinous spacer (Superion) versus those treated with an FDA-approved spacer (X-STOP). One hundred sixty-six patients with moderate lumbar spinal stenosis (LSS) unresponsive to conservative care were treated randomly with the Superion (n = 80) or X-STOP (n = 86) interspinous spacer. Study subjects were followed through 6 months posttreatment. Zurich Claudication Questionnaire (ZCQ) symptom severity scores improved 30% with Superion and 25% with X-STOP (both P < 0.001). Similar changes were noted in ZCQ physical function with improvements of 32% with Superion and 27% with X-STOP (both P < 0.001). Mean ZCQ patient satisfaction score ranged from 1.7 to 2.0 in both groups at all follow-up visits. The proportion of subjects that achieved at least two of three ZCQ clinical success criteria at 6 months was 75% with Superion and 67% with X-STOP. Axial pain decreased from 55 ± 27?mm at pretreatment to 22 ± 26?mm at 6 months in the Superion group (P < 0.001) and from 54 ± 29?mm to 32 ± 31?mm with X-STOP (P < 0.001). Extremity pain decreased from 61 ± 26?mm at pretreatment to 18 ± 27?mm at 6 months in the Superion group (P < 0.001) and from 64 ± 26?mm to 22 ± 30?mm with X-STOP (P < 0.001). Back function improved from 38 ± 13% to 21 ± 19% with Superion (P < 0.001) and from 40 ± 13% to 25 ± 16% with X-STOP (P < 0.001). Preliminary results suggest that the Superion interspinous spacer and the X-STOP each effectively alleviate pain and improve back function in patients with moderate LSS who are unresponsive to conservative care. PMID:22448323

Miller, Larry E; Block, Jon E



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


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

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



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.



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


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




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.

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



Surface composition analysis of failed cementless CoCr- and Ti-base-alloy total hip implants.  


The surfaces of retrieved failed cementless total hip implants made of cobalt-chromium-molybdenum casting alloy and of wrought titanium 6-aluminum 4-vanadium alloy were studied with the use of scanning-electron microscopy (SEM), energy-dispersive X-ray analysis (EDX) and X-ray photoelectron spectroscopy (XPS). New implants of the same make served as controls. The XPS scans revealed a dense carbon layer on the entire analyzed specimen. The relative composition of the titanium alloy implants showed an overall agreement with the international standards for implants for surgery, and the overall surface composition did not change over the period of the implantation. However, an inhomogeneous distribution of the constituents could be demonstrated in the retrieved as well as in the new MEC-screw rings made of TiAl6V4 alloy, an implant that has been linked to a high early failure rate. In the CoCr-alloy components (Lord-screw rings) a high percentage of aluminum, mainly organized in aluminum inclusions, was found in the retrieved as well as in the new implants. PMID:12516084

Decking, R; Reuter, P; Hüttner, M; Puhl, W; Claes, L E; Scharf, H P



Successful staged hip replacement in septic hip osteoarthritis in osteopetrosis: a case report  

PubMed Central

Background Osteopetrosis is a rare, inherited, bone disorder, characterized by osteosclerosis, obliteration of the medullary cavity and calcified cartilage. The autosomal dominant form is compatible with a normal life span, although fractures often result from minimal trauma, due to the pathologic nature of bone. Osteomyelitis is common in patients with osteopetrosis because of a reduced resistance to infection, attributed to the lack of marrow vascularity and impairment of white cell function. Only one case of osteomyelitis of the proximal third of the femur has been previously reported, treated with several repeated debridements and finally with femoral head resection. Here we present for the first time a case of a staged implant of a cementless total hip prosthesis for the treatment of a septic hip in femoral neck nonunion in osteopetrosis. Case presentation A 36-years-old woman, affected by autosomal dominant osteopetrosis was referred to our department because of a septic hip arthritis associated with femoral neck septic non-union, with draining fistulas. The infection occurred early after a plate osteosynthesis for a closed perthrocanteric fracture of the femur and persisted in spite of osteosynthesis removal, surgical debridement and external fixation. In our hospital the patient underwent accurate debridement, femoral head and greater trochanter resection, preparation of the diaphyseal intramedullary canal and implant of an antibiotic-loaded cement spacer. The spacer was exchanged after one month, due to infection recurrence and four months later, a cementless total hip arthroplasty was implanted, with no clinical and laboratory signs of infection recurrence at two years follow-up. Conclusions In case of hip septic arthritis and proximal femur septic non-union, femoral head resection may not be the only option available and staged total hip arthroplasty can be considered.



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


Two-year results of interspinous spacer (X-Stop) implantation in 175 patients with neurologic intermittent claudication due to lumbar spinal stenosis  

PubMed Central

The clinical outcome of patients with symptomatic lumbar spinal stenosis (LSS) was assessed during a follow-up period of 2 years after X-Stop implantation. The X-Stop is the most commonly used interspinous distraction device in patients with neurogenic intermittent claudication due to LSS. Between 2003 and 2007, more than 1,000 patients were examined in our centre with symptoms of intermittent claudication due to spinal stenosis. Between February 2003 and June 2007, in 175 of these patients an X-Stop device was implanted in one or two levels. Patients were clinically evaluated regularly during a follow-up period of up to 4 years using the VAS (leg pain) score and the Oswestry disability index. The mean VAS (leg pain) score in these 175 patients was reduced from 61.2% preoperatively to 39.0% at the first clincal follow-up examination at 6 weeks postoperatively. The mean VAS score at 24 months postoperatively was 39.0%. Oswestry score was 32.6% preoperatively, 22.7% at 6 weeks, and 20.3% at 24 months postoperatively on average. In eight out of the implanted 175 patients, the X-Stop had to be removed and a microsurgical decompression had to be performed because of unsatisfactory effect of the interspinous distraction device. Our single-centre results indicate not only a satisfactory short-term, but also a good long-term effect during a follow-up period of 2 years. Functional MRI examinations provide helpful, positional-dependent preoperative information. More than any radiological feature, the typical clinical picture of positional-dependent claudication with a relief of symptoms during flexion is the most important factor for appropriate patient selection. The interspinous device does not replace microsurgical decompression in patients with massive stenosis and continuous claudication, but offers a save, effective and less invasive alternative in selected patients with spinal stenosis. Concerning the operative technique, a minimally invasive implantation with preservation of the interspinous ligament is appropriate. Functional (upright-) MRI examinations were able to demonstrate the positional-dependent stenosis. If available, fMRI represents the most helpful radiologic examination in assessing the outcome of interspinous spacer implantation.

Sobottke, Rolf; Eysel, Peer; Simons, Patrick



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


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

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



Comparison of in vitro with in vivo characteristics of wear particles from metal-metal hip implants.  


The purpose of the present study was to compare wear particles isolated from metal-metal (MM) hip implants worn in an orbital bearing simulator with particles from similar MM total hip replacement (THR) implants worn in vivo. Comparison of these particles is important because it will help to assess the overall suitability of this type of hip simulator for reproducing in vivo wear and for producing physiological wear particles suitable for biological studies of in vitro cellular response. Commercial grade components made of ASTM F75 (cast) alloy were evaluated. Simulator tests were performed in 95% bovine calf serum with a 28-mm-diameter implant. Wear particles were collected from 0 to 0.25 million cycles (run-in wear period) and 1.75 to 2 million cycles (steady-state wear period). Tissues from seven patients with MM implants (surface replacement or stem type) were harvested at revision surgeries (after 1-43 months). Metal wear particles were isolated from serum lubricant or tissues using an enzymatic protocol that was previously optimized to minimize particle changes due to reagents. After isolation, particles were centrifuged, embedded in epoxy resin, and characterized by transmission electron microscopy (TEM) and energy dispersive X-ray analysis (EDXA). Results of EDXA on particles from the hip simulator primarily indicated a predominance of particles containing Cr and O but no Co (most likely chromium oxide particles), and fewer CoCrMo particles presenting varying ratios of Co and Cr. Image analysis of TEM micrographs demonstrated that the majority of the particles from the simulator were round to oval, but a substantial number of needle-shaped particles were also found, especially from 0 to 0.25 Mc. The particles generated from 0 to 0.25 Mc had an average length of 53 nm, whereas those generated from 1.75 to 2 Mc had an average length of 43 nm. In vivo, EDXA and TEM analysis of particles that were retrieved from two patients at 23 and 43 months respectively, revealed that they were the most comparable in composition, average length (57 nm), and shape to particles generated in the hip simulator during the run-in wear period. Because a large clinical retrieval study in the literature suggested that a run-in wear regime might occur in vivo for some 6-36 months, the fidelity of the simulator of the present study was strongly supported. However, some uncertainties existed, including the finding that the particles isolated from the other five patients generated from 1 month up to 15 months (shorter implantation times than the other two patients) were smaller and mostly contained only Cr and O (no Co). In the opinion of the authors, this particular very short term patient group was somewhat atypical. Therefore, despite these uncertainties, the present study was deemed to support the ability of the orbital bearing hip simulator to produce physiological wear particles. PMID:15264297

Catelas, Isabelle; Medley, John B; Campbell, Pat A; Huk, Olga L; Bobyn, J Dennis



Contact mechanics of metal-on-metal hip implants employing a metallic cup with a UHMWPE backing.  


The contact mechanics in metal-on-metal hip implants employing a cobalt chromium acetabular cup with an ultra-high molecular weight polyethylene (UHMWPE) backing were analysed in the present study using the finite element method. A general modelling methodology was developed to examine the effects of the interfacial boundary conditions between the UHMWPE backing and a titanium shell for cementless fixation, the coefficient of friction and the loading angle on the predicted contact pressure distribution at the articulating surfaces. It was found that the contact mechanics at the bearing surfaces were significantly affected by the UHMWPE backing. Consequently, a relatively constant pressure distribution was predicted within the contact conjunction, and the maximum contact pressure occurred towards the edge of the contact. On the other hand, the interfacial boundary condition between the UHMWPE backing and the titanium shell, the coefficient of friction and the loading angle were found to have a negligible effect on the contact mechanics at the bearing surfaces. Overall, the magnitude of the contact pressure was significantly reduced, compared with a similar cup without the UHMWPE backing. The importance of the UHMWPE backing on the tribological performance of metal-on-metal hip implants is discussed. PMID:12807161

Liu, F; Jin, Z M; Grigoris, P; Hirt, F; Rieker, C



Role of ceramic implants. Design and clinical success with total hip prosthetic ceramic-to-ceramic bearings.  


Ceramic implants have become of great interest because of the increased awareness that wear debris from metal-polyethylene components of total hip prostheses can cause osteolysis around implants. Polyethylene wear rates with the Charnley total hip prosthesis were found to be from 0.1 to 0.2 mm/year in the elderly, which corresponded to 30 to 80 mm3 of polyethylene debris being released to the joint tissues. This in turn can be related to 40 million to 40 billion particles being released into the joint every year. This polyethylene particulate is heavily implicated in the osteolytic destruction of periarticular tissues. The ceramic ball, ceramic cup combination of total hip prostheses may have promise of wear rates that could be thousands of times smaller than polyethylene alone. Such alumina ceramic prosthetic concepts were introduced in Europe from 1970 to 1973. Under Food and Drug Administration regulations at that time, the only U.S. introductions allowed circa 1980 were the Autophor and Xenophor types of ceramic prostheses. However, this particular prosthetic design was not successful in the United States because of pain, neck-socket impingement, ceramic fracture, and component loosening. This did not therefore appear to be a successful compromise in the hands of U.S. surgeons. Ceramic innovations from Europe now include cemented ceramic cups of "matching" tolerances with the femoral ball, and press-fit Ti-alloy acetabular shells with modular ceramic inserts. In addition, alumina and zirconia ceramic balls are now in routine clinical use in Europe. The objectives of this Symposium are to highlight these ceramic ball, ceramic cup innovations with their long-term clinical results from Europe. Then one can evaluate which of these innovations in material and design selections offers the best possible alternatives in the 1990s. PMID:1516312

Clarke, I C



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.



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.



Handling modular hip implants in model-based RSA: Combined stem–head models  

Microsoft Academic Search

Migration measurements of hip prostheses using marker-based Roentgen stereophotogrammetric analysis (RSA) require the attachment of markers to the prostheses. The model-based approach, which does not require these markers, is, however, less precise. One of the reasons may be the fact that the spherical head has not been modelled. Therefore, we added a 3D surface model of the spherical head and

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



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


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

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



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


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

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



[Influence of prosthesis design on intramedullary pressure formation in femur shaft implants of cemented hip endoprostheses].  


The increase of intramedullary femoral pressure can lead to the intravasation of bone marrow and fat cells into the blood stream of the femoral vein and consequently into the pulmonary circulation. This effect is the same in intramedullary nailing and in the implantation of femoral stem prostheses. In a prospective study we evaluated the intraoperative, intramedullary pressure in the distal femur during the implantation of femoral stem prostheses with two different designs. In eight patients we implanted Müller straight stems and in another eight we implanted stem type Option 3000. Intramedullary pressure was recorded continuously by the implantation of a microtip pressure probe (piezoresistive principle, 50 Hz) in the distal femur. We found markedly higher pressure in Müller straight stem prostheses: range: 590-2,570 mmHg (median = 1,293, SD = 627 mmHg). Intramedullary pressure in stem prosthesis type Option 3000 was much lower: range: 59-574 mmHg (median = 289, SD = 219 mmHg). The differences were statistically significant (p = 0.0008). By changing the designs of femoral stem prostheses, the intramedullary pressure can be markedly reduced. In the case of elderly patients or those with pulmonary illness we recommend femoral stem prosthesis designs, which induce little increase in the intramedullary pressure, in order to reduce cardiopulmonary complications. PMID:11803720

Beck, A; Strecker, W; Gebhard, F; Arand, M; Krischak, G; Kinzl, L



Peroperative fractures in uncemented total hip arthrography: results with a single design of stem implant  

PubMed Central

The incidence of intraoperative femoral fractures with a single design of stem implant, the Meridian (Stryker-Howmedica, Rutherford, N.J.), has been assessed in a study of 117 implants in patients treated consecutively between 1996 and 2001. The aim of the study was to evaluate the risk factors for suffering an intraoperative fracture and to determine, based on a short-term follow-up, if there were radiographic signs of early loosening. The following variables were analysed: demographic factors of the patient, morphology of the femur, intraoperative factors and postoperative radiographic factors. The radiographic stability of the implant and the presence of early signs of loosening were evaluated 2 years after surgery. The incidence of femoral fractures was 11% (13 cases in 117 implants), which is higher that reported in earlier published studies, and there was an increased number of fractures when the proximal filling of the femoral canal was higher. Although there was no statistically significant relation between the variables studied and the appearance of an intraoperative fracture, we conclude that the appearance of a femoral intraoperative fracture did not affect the radiographic stability of the implant during the short-term follow-up of our study cohort.

Garcia-Elias, Elena; Gil-Garay, Enrique



[Technical principles for removal of femoral bone cements in hip prosthesis implant revision].  


As the removal of femoral bone cement is one of the most challenging tasks in cemented total Hip Revision, a lot of different technical devices have been developed to aid the surgeon. All of their pros and cons are partly consequences of the specific system-design but mainly arise from the basic physical principles used. The known methods and devices as well as their data-handling have therefore been analysed, reduced to their principles according to the criteria of systematic engineering design and systematized in order to provide a better comparability and starting point for the development of new devices. PMID:12451769

Lauer, W; Neuss, M; Wirtz, D C; Radermacher, K



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


The reduction of artifacts due to metal hip implants in CT-attenuation corrected PET images from hybrid PET\\/CT scanners  

Microsoft Academic Search

CT beam hardening artifacts near metal hip implants may erroneously enhance or diminish radiotracer uptake following CT attenuation\\u000a correction (AC) of PET images. An artifact reduction algorithm (ARA) was developed to reduce metal artifacts in CT-based AC-PET.\\u000a The algorithm employed a Bayes classifier to identify beam-hardening artifacts, followed by a partial correction of the attenuation\\u000a map. ARA was implemented on

John A. Kennedy; Ora Israel; Alex Frenkel; Rachel Bar-Shalom; Haim Azhari



Influence of design parameters on cup-stem orientations for impingement free RoM in hip implants.  


This study was conducted to study the influence of design parameters namely; the head/neck ratio (R), neck-shaft angle (NSA), oscillation angle (OsA) and stem offset (S?) on cup-stem orientations namely; the cup inclination (CI), cup anteversion (CA) and stem antetorsion (SA). R is often linked to influence NSA, OsA and impingement. An effort has been made to analyze range of motion (RoM) with NSA greater than 135° and R lower than 2.3 that may produce impingement. This study attempted to answer the following assumptions whether (a) implants with higher H-N ratio can achieve higher oscillations and higher stem antetorsion, (b) stems with higher neck shaft angle can achieve higher cup anteversion with lower stem offset and stem antetorsion, (c) stem with higher offsets can achieve lower cup anteversion with higher stem antetorsion, and (d) lower cup anteversion can be achieved when stem antetorsion is higher. A theoretical and a simulated method were implemented to anaylze RoM until impingement between cup and neck occurred. Cup abduction and anterior opening were held constant for this study. Multivariate prediction models were developed to predict optimal cup-stem orientations for the chosen design parameters of 12 hip implants. Optimal design parameters to achieve an impingement free RoM were as follows: NSA=139.25°, R=3.08, OsA=119.83°, S?=34.45mm, CA(predicted)=16.26°, CI(predicted)=42.77° and SA(predicted)=30.37°, respectively. Multivariate models may be further developed for use in surgery planning to achieve optimal component placement. PMID:21978913

Patel, Dishita; Goswami, Tarun



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


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



[Comparison between early and late inpatient rehabilitation measures after implantation of total hip endoprostheses].  


This study was aimed at answering the question of whether a four-week inpatient early rehabilitation programme, i.e. within the first two months following total hip replacement surgery, will have a favourable impact as compared to later-onset inpatient rehabilitation measures; a total of 219 patients was studied: 137 were admitted during the first two months post-op (group A), 45 within three to four months post op (group B), and 37 patients were admitted at a later date (group C). Assessments were carried out for pain, walking performance and self-help status (scores) as well as for mobility, gait patterns, walking aids, walking speed, and disablement. In group A patients, significant improvement was achieved for all of these parameters: at the end of the rehabilitation programme (2.4 months post-op) these patients already were more mobile than group B patients at the time of admission (3.3 months post-op). In group B, improvements were found for several parameters. At a later time, the natural healing process had brought about so good a baseline situation in the group C patients that no further improvement was possible. The 162 patients treated successfully, i.e. where score reductions occurred, had been admitted significantly (p = 0.0001) earlier (2.9 months post-op) than the remaining 57 patients (5.7 months post-op). Some 14 months after programme participation, follow-up examinations were possible for 90 patients of group A, and for 27 patients from groups B and C. Further significant improvements had occurred in group A patients only, notably relative to muscle strength and reduction of walking aids. It is concluded from our data that inpatient early rehabilitation will achieve the greatest effect and will substantially reduce the recovery phase with its mobility limitations and daily living handicaps. PMID:9789313

Scherak, O; Kolarz, G; Wottawa, A; Maager, M; el Shohoumi, M



Fate of ultrahigh molecular weight polyethylene (UHMW-PE) wear debris in patients with hip implants.  


The process of ultrahigh molecular weight polyethylene (UHMW-PE) breakdown, started at the articular surface of the cup, continues in small fragments after generation. An assiduous interaction between the UHMW-PE particles and the host cells leads to oxidative changes of the UHMW-PE and to size reduction of the particles simultaneous with transporting them toward, and finally by, lymphatic or blood vessels. The particles are mobilized by means of enzymatic, extracellular matrix-degrading activity of cells that have phagocytosed them or adhered to them. Together, these characteristics indicate an attempt by the natural cellular immunity system to eliminate the implant wear debris. Macrophages are the main effector cells acting as scavengers; however, excessive amount of the wear debris evokes phagocytic activity of cells other than macrophages as well. PMID:11539273

Witkiewicz, H; Vidovszky, T; Turner, R T; Rock, M G; Morrey, B F; Bolander, M E



Quantification of stem-cement interfacial gaps: in vitro CT analysis of Charnley-Kerboul and Lubinus SPII femoral hip implants.  


Interfacial defects between the cement mantle and a hip implant may arise from constrained shrinkage of the cement or from air introduced during insertion of the stem. Shrinkage-induced interfacial porosity consists of small pores randomly located around the stem, whereas introduced interfacial gaps are large, individual and less uniformly distributed areas of stem-cement separation. Using a validated CT-based technique, we investigated the extent, morphology and distribution of interfacial gaps for two types of stem, the Charnley-Kerboul and the Lubinus SPII, and for two techniques of implantation, line-to-line and undersized. The interfacial gaps were variable and involved a mean of 6.43% (sd 8.99) of the surface of the stem. Neither the type of implant nor the technique of implantation had a significant effect on the regions of the gaps, which occurred more often over the flat areas of the implant than along the corners of the stems, and were more common proximally than distally for Charnley-Kerboul stems cemented line-to-line. Interfacial defects could have a major effect on the stability and survival of the implant. PMID:18160511

Scheerlinck, T; Vandenbussche, P; Noble, P C; Dunn, John S



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

PubMed Central

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

Jaeger, Gry T; Larsen, Stig; S?li, Nils; Moe, Lars



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


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

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



Sonication of antibiotic-loaded cement spacers in a two-stage revision protocol for infected joint arthroplasty  

PubMed Central

Background Culturing of the sonication fluid of removed implants has proven to be more sensitive than conventional periprosthetic tissue culture for the microbiological diagnosis of prosthetic joint infection. Since bacteria surviving on antibiotic-loaded cement spacers used in a two-stage exchange protocol for infected arthroplasties may cause the persistence of infection, in this study we asked whether the sonication also could be used to identify bacteria on antibiotic-loaded cement spacers removed at the second surgical stage during a two-stage exchange procedure to confirm whether or not the prosthetic joint infection had been eradicated. Methods We cultured the sonication fluid of cement spacers that had been originally implanted in a two-stage exchange protocol in 21 patients (mean age, 66 years) affected by prosthetic joint infection (16 total knee prostheses and 5 hip prostheses). The cement spacers were vortexed for 30 seconds and then subjected to sonication (frequency 35–40 KHz). The resulting sonicate fluid was cultured for aerobic and anaerobic bacteria. Results The sonication fluid culture of the removed spacer was positive in six patients (29%), with isolation of methicillin-sensible Staphylococcus Aureus (MSSA) in three cases, methicillin-resistant Staphylococcus Aureus (MRSA) in one case and Pseudomonas Aeruginosa in two cases. In three of these positive cases, the traditional culture of periprosthetic tissue was negative. Two patients with positive sonication culture of the spacer were successfully treated by early debridement of the revision prosthesis and systemic antibiotic therapy. In three patients a knee arthrodesis was planned and performed as the second surgical stage. In two of them the infection was caused by highly resistant Pseudomonas Aeruginosa. The other patient with a MSSA infection had been poorly compliant with the systemic antibiotic therapy due to her mental impairment. The patient originally affected by MRSA infection of his primary hip arthroplasty developed recurrent infection of his revision prosthesis and eventually underwent Girdlestone arthroplasty. Conclusions The sonication culture can be used to discover any bacteria on the antibiotic-loaded cement spacer during a two-stage exchange protocol, thus permitting the adoption of timely treatment options, such as the early prosthetic debridment.



Radiographic identification of loose bodies in the traumatized hip joint  

SciTech Connect

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

Baird, R.A. (Univ. of California at Irvine, Orange); Schobert, W.E.; Pais, M.J.; Ahmed, M.; Wilson, W.J.; Farjalla, G.L.; Imray, T.J.



Double-blind, placebo-controlled trial of the pain-relieving effects of the implantation of gold beads into dogs with hip dysplasia.  


Seventy-eight dogs with pain due to hip dysplasia were studied in a controlled, double-blind clinical trial to evaluate gold bead implantation as a pain-relieving treatment. The dogs were randomly assigned to two groups, 36 in the gold implantation group and 42 in the placebo group. Both groups were treated equally regarding anaesthesia, hair clipping and penetration of the skin with the same type of needle. The gold implantation group had small pieces of 24 carat gold inserted through needles at five different acupuncture points and the placebo group had the skin penetrated at five non-acupuncture points so as to avoid any possible effect of stimulating the acupuncture points. A certified veterinary acupuncturist marked the points, and two surgeons performed the implantations according to a randomisation code made in advance. After 14 days, three months and six months, the owners assessed the overall effect of the treatments by answering a questionnaire, and the same veterinarian examined each dog and evaluated its degree of lameness by examining videotaped footage of it walking and trotting. The treatment was blinded for both the owners and the veterinarian. There were significantly greater improvements in mobility and greater reductions in the signs of pain in the dogs treated with gold implantation than in the placebo group. The veterinarian's and the owners' assessments corresponded well. PMID:16731702

Jaeger, G T; Larsen, S; Søli, N; Moe, L



OCH Spacer Design  

SciTech Connect

The purpose of the OCH module spacers is to keep the given dimension of .224-inch between the 1.83-inch absorber plates. This distance is determined by two liquid argon gaps of .09-inch each and a readout board of .044-inch. The spacer should be made out of a material that would give a minimum thermal contraction movement. Also the dimension of the spacer will be determined dependent upon the load applied to the spacers and the strength of the material chosen. Considering both thermal contraction and yield strength, it is found that Invar-36 would be a suitable material from which to make the spacers for the OCh module, provided that SS304 washers are used in conjunction with the spacers. The spacers would be positioned about 1-inch from the corners of each of the copper plates, and would have a diameter of about 0.85453399-inch. The thickness of the Invar spacer would be 0.15394250-inch and that of the SS304 would be 0.07005750-inch. This combination of materials used for spacing purposes should result in zero displacement due to thermal contraction and no buckling due to overloading. The actual design of the spacer can be found in DWG.

Kurita, C.H.; /Fermilab



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.



Foreign body reaction to artelon spacer: case report.  


Anecdotal reports of painful synovitis after implantation of the Artelon spacer (Small Bone Innovations, Inc., Morrisville, PA) have emerged. The manufacturer claims that this type of reaction is related to the method of fixation and/or to suture material. This report illustrates one case in which a patient exhibited sustained painful synovitis after implantation of the Artelon spacer in the scaphotrapezio-trapezoidal joint, which clinically resolved on removal of the implant. Furthermore, pathology specimens of the soft tissue, synovium, and bone demonstrated an exuberant granulomatous foreign body giant cell reaction to the implant material. Patients should be made aware of the potential of the Artelon spacer to cause a foreign body reaction that may necessitate reoperation for removal of the implant. PMID:19801107

Giuffrida, A Ylenia; Gyuricza, Cassie; Perino, Giorgio; Weiland, Andrew J



Two-year results of interspinous spacer (X-Stop) implantation in 175 patients with neurologic intermittent claudication due to lumbar spinal stenosis  

Microsoft Academic Search

The clinical outcome of patients with symptomatic lumbar spinal stenosis (LSS) was assessed during a follow-up period of 2 years\\u000a after X-Stop implantation. The X-Stop is the most commonly used interspinous distraction device in patients with neurogenic\\u000a intermittent claudication due to LSS. Between 2003 and 2007, more than 1,000 patients were examined in our centre with symptoms\\u000a of intermittent claudication due

Johannes Kuchta; Rolf Sobottke; Peer Eysel; Patrick Simons



Is Patient Selection Important for Hip Resurfacing?  

Microsoft Academic Search

The optimal implant option for hip arthroplasty in the young, active patient remains controversial. There has been renewed\\u000a interest for metal-on-metal hip resurfacing due to improved design and manufacturing of implants, better materials, enhanced\\u000a implant fixation, theoretical advantages over conventional total hip arthroplasty, and recent Food and Drug Administration\\u000a approval of two devices. Recent studies indicate satisfactory short- and midterm

Ryan M. Nunley; Craig J. Della Valle; Robert L. Barrack



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


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

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



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



Revision of late periprosthetic infections of total hip endoprostheses: pros and cons of different concepts  

PubMed Central

Many concepts have been devised for the treatment of late periprosthetic infections of total hip prostheses. A two-stage revision with a temporary antibiotic-impregnated cement spacer and a cemented prosthesis appears to be the most preferred procedure although, in recent times, there seems to be a trend towards cementless implants and a shorter period of antibiotic treatment. Because of the differences in procedure, not only between studies but also within studies, it cannot be decided which period of parenteral antibiotic treatment and which spacer period is the most suitable. The fact that comparable rates of success can be achieved with different treatment regimens emphasises the importance of surgical removal of all foreign materials and the radical debridement of all infected and ischaemic tissues and the contribution of these crucial procedures to the successful treatment of late periprosthetic infections.

Fink, Bernd



Hip fracture  

PubMed Central

Introduction Between 12% and 37% of people will die in the year after a hip fracture, and 10% to 20% of survivors will move into a more dependent residence. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of surgical interventions in people with hip fracture? What are the effects of perisurgical medical interventions on surgical outcome and prevention of complications in people with hip fracture? What are the effects of rehabilitation interventions and programmes after hip fracture? We searched: Medline, Embase, The Cochrane Library, and other important databases up to April 2009 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 55 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: anaesthesia (general, regional); antibiotic regimens; arthroplasty; choice of implant for internal fixation; conservative treatment; co-ordinated multidisciplinary approaches for inpatient rehabilitation of older people; cyclical compression of the foot or calf; early supported discharge followed by home-based rehabilitation; extramedullary devices; fixation (external, internal); graduated elastic compression; intramedullary devices; mobilisation strategies; nerve blocks for pain control; nutritional supplementation (oral multinutrient feeds, nasogastric feeds); perioperative prophylaxis with antibiotics, with antiplatelet agents, or with heparin (low molecular weight or unfractionated); preoperative traction to the injured limb; and systematic multicomponent home-based rehabilitation.



Effect of bearing geometry and structure support on transient elastohydrodynamic lubrication of metal-on-metal hip implants  

Microsoft Academic Search

An effective lubrication can significantly reduce wear of metal-on-metal artificial hip joints. The improvement of the lubrication can be achieved through the optimisation of the bearing geometry in terms of a small clearance and\\/or the structural support such as a polyethylene backing underneath a metallic bearing in a sandwich acetabular cup form. The separate effects of these two factors on

Feng Liu; Zhongming Jin; Paul Roberts; Peter Grigoris



One-stage revision of septic hip prosthesis with antibiotic-loaded bone grafts and cementless implants  

Microsoft Academic Search

Infection of total hip replacement (THR) is a serious complication, necessitating its complete removal and thorough debridement\\u000a of the site. Usually long-term antibiotic treatment and a multitude of surgical interventions within a period of several months\\u000a are required until a definitive supply can be achieved. One-stage exchange using antibiotic containing cement did not gain\\u000a widespread use because of several risks,

H. Winkler



In vivo corrosion of 316L stainless-steel hip implants: morphology and elemental compositions of corrosion products  

Microsoft Academic Search

Eleven surgically retrieved stainless steel implants showing varying degrees of surface corrosion were examined to characterize the morphology and composition of corrosion products. The implants were fabricated to the specification AISI316L (Müller) and BS 3531 pt 1 1971–78 (Charnley). They had been in place for 9–21y (Mean :13y) and failures were due to aseptic loosening. The morphology and chemical compositions

J. Walczak; F. Shahgaldi; F. Heatley



Side insertable spacer  

SciTech Connect

This patent describes a spacer for restraining the fuel rods of a nuclear fuel assembly, the assembly being formed of a plurality of parallel, elongated fuel rods so arranged that the assembly is bounded by a polygon having an even number of sides, the rods being so arranged as to lie in a plurality of sets of parallel rows, the rows of each set being perpendicular to one of the sides of the polygon. It comprises a number of spacer combs equal to at least half the number of the sides of the polygon, the spacer combs being superposed on each other, each of the spacer combs comprising: a single base strip having a length equal to that of one of the sides of the polygon and grid strips equal in number to the spaces between rows in one of the sets, and at least a majority of the grid strips being of a length sufficient to extend substantially the full length of the rows; the grid strips being provided with spring members positioned to engage each of the rods; the grid strips being provided with spring members positioned to engage each of the rods; the grid strips being secured to and extending at right angles to the base strip; the grid strips of different combs being positioned at angles to each other, so as to occupy the spaces between rows in different sets.

Patterson, J.F.; Ewing, R.H.



What's New In Hip Surgery?  

PubMed Central

The problems of late loosening of conventional total hip replacements in young people with one joint disease have spurred the development of alternative designs of hip replacement. Two such developments have reached the stage of clinical application. In the double cup arthroplasty, only the damaged joint surfaces are replaced. This makes revision surgery, if required, very much simpler. In porous metal hip replacement, the stems of the prosthesis are porous coated to allow bone ingrowth which locks the implant firmly in place. This dispenses with the use of polymethylmethacrylate, which is the weakest part of the conventional total hip replacement system. Imagesp1036-a

Cameron, H. U.




Microsoft Academic Search

\\u000a This chapter describes required facilities, preoperative procedures, anesthesia, and operative techniques for the implantation\\u000a of currently available defibrillator models. Electrophysiologists would prefer not to have to think about the days when defibrillator\\u000a implantations were performed using a median sternotomy with mortality rates exceeding five percent. The size reduction of\\u000a the generators and the use of transvenous leads have allowed subcutaneous

Antonio Pacifico; Philip D. Henry


Hip endoprosthesis for in vivo measurement of joint force and temperature  

Microsoft Academic Search

Friction between the prosthetic head and acetabular cup increases the temperature in hip implants during activities like walking. A hip endoprosthesis was instrumented with sensors to measure the joint contact forces and the temperature distribution along the entire length of the titanium implant. Sensors and two inductively powered telemetry units are placed inside the hip implant and hermetically sealed against

Friedmar Graichen; Georg Bergmann; Antonius Rohlmann



Combined anteversion of the total hip arthroplasty implanted with image-free cup navigation and without stem navigation  

PubMed Central

In total hip arthroplasty (THA), combined anteversion (CA), the sum of cup anteversion (AV) and stem antetorsion (AT) are used as parameters to assess the appropriateness of overall prosthetic alignment. In this study, we evaluated the CA value based on the post-operative computed tomography (CT) measurements in our patient population who underwent THA using the OrthoPilot™ image-free navigation system (B/BRAUN-Aesculap, Tuttlingen, Germany). During surgery, cup alignment was adjusted with the use of the navigation system while the positioning of the femoral stem was arbitrarily adjusted by the surgeon. Seventy-nine THAs were included in the study. Post-operative CT assessment for the prosthetic alignment showed the average cup inclination and AV values to be 40.5°±4.1° and 20.6°±4.6°, respectively, demonstrating the effectiveness of the navigation system by small values of standard deviation. By contrast, the AT value measured for the stem showed wide variability (mean 23.6°±11.2°). Consequently, the resulting CA was also inconsistent (mean 44.4°±11.2°) and only 61 of the 79 THAs (77.2%) were defined as satisfactory.

Fukunishi, Shigeo; Fukui, Tomokazu; Nishio, Shoji; Fujihara, Yuki; Okahisa, Shohei; Yoshiya, Shinichi



Combined anteversion of the total hip arthroplasty implanted with image-free cup navigation and without stem navigation.  


In total hip arthroplasty (THA), combined anteversion (CA), the sum of cup anteversion (AV) and stem antetorsion (AT) are used as parameters to assess the appropriateness of overall prosthetic alignment. In this study, we evaluated the CA value based on the post-operative computed tomography (CT) measurements in our patient population who underwent THA using the OrthoPilot™ image-free navigation system (B/BRAUN-Aesculap, Tuttlingen, Germany). During surgery, cup alignment was adjusted with the use of the navigation system while the positioning of the femoral stem was arbitrarily adjusted by the surgeon. Seventy-nine THAs were included in the study. Post-operative CT assessment for the prosthetic alignment showed the average cup inclination and AV values to be 40.5°±4.1° and 20.6°±4.6°, respectively, demonstrating the effectiveness of the navigation system by small values of standard deviation. By contrast, the AT value measured for the stem showed wide variability (mean 23.6°±11.2°). Consequently, the resulting CA was also inconsistent (mean 44.4°±11.2°) and only 61 of the 79 THAs (77.2%) were defined as satisfactory. PMID:23589761

Fukunishi, Shigeo; Fukui, Tomokazu; Nishio, Shoji; Fujihara, Yuki; Okahisa, Shohei; Yoshiya, Shinichi



Hip Fractures  


... cases, if the patient falls and complains of hip pain, an incomplete fracture may not be seen on ... injuries may be approached either from either the front or back of the hip. In some cases, both approaches are required in ...


Hip Pain  


... 0/1807/0.html. Accessed May 13, 2013. Anderson BC. Evaluation of the adult with hip pain. ... Accessed May 13, 2013. Anderson BC. Patient information: Hip pain (Beyond the basics). ...


Hip Replacement  


... hip joint work better Improve walking and other movements The most common problem after surgery is hip dislocation. Because a man-made hip is smaller than the original joint, the ball can come out of its socket. The surgery can also cause blood ...


[Anatomic reconstruction of hip joint biomechanics with the bone preserving silent micro hip™ prosthesis].  


Background: The design and the surgical technique of the Silent Micro Hip™ are different compared to other hip stems due to a conical shape for fixation within the metaphyseal femur. The purpose of the present study was to evaluate hip joint biomechanics of the Silent Micro Hip™ in comparison to other implants. Implant-specific differences are highlighted. Material and Method: 150 consecutive patients (each group 50 Silent Micro Hip™, Nanos™ and SL-Plus™ MIA) were analysed retrospectively. For evaluation of biomechanical parameters pre- and postoperative X-rays (pelvic AP views) were used. Results: The horizontal femoral offset and the limb length showed no significant difference between the Silent Micro Hip™ and the Nanos™ or SL-Plus™ MIA stem at the reconstructed hip. An almost anatomic reconstruction of hip joint biomechanics was reached with all three types of implants.Conclusions: The Silent Micro Hip™ allows for almost anatomic reconstruction of hip joint biomechanics. Short-term results support the bone-preserving reconstruction with a proximal femoral load transfer. Further studies on the mid- and long-term outcomes are ongoing. PMID:24129720

Ries, C; Schopf, W; Dietrich, F; Franke, S; Jakubowitz, E; Sobau, C; Heisel, C



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


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

Microsoft Academic Search

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

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



[Design of an unconventional interlocked hip arthroplasty system (RIMAG) from Mexican femoral measurement].  


The need in resolving massive bone losses in hip region caused by tumors, infections, trauma or failed arthroplasties in 17 years of the Bone Tumors Department of the National Rehabilitation Institute, Mexico City, and data obtained from different studies: 1) Biomechanic study of an unconventional hip arthroplasty system, 2) Tridimensional model of a human femur by the finite element method, 3) Biomechanical analysis of a system bone-implant for reconstruction of the proximal third of the femur by the finite element method, 4) Incidence of tumor and pseudotumor bone and soft tissue lesions of the hip, generated the project of designing an unconventional interlocked hip arthroplasty system for femur reconstruction. Two processes were done for adequate manufacturing and dimensioning: Anthropomorphometric study of Mexican femora; 2) Design of an unconventional hip arthroplasty system with the following characteristics: first, the arthroplasty system is constituted by an intramedullar stem, is fixated to femur with interlocking screws, this fixation method was inspired from the design of intramedullar nails of Dr. Fernando Colchero Rosas. The system has a second fixation system in the femur cut region, resolved by a fenestrated support introduced in the cortical wall. Once data was processed, the need for manufacturing 2 models was determined: 1) One for the proximal 11 cm of the femur and 2) other for the 12 distal cm. The height of interlocking screws, 2 models of intracortical proximal support (one fixated and one fixable with an expansible screw), were designed. Diameter, length of the stems, size of spacers and supports were determined for adequate interlocking fixation. We designed the instruments for assembling, impaction and orientation of the arthroplasty system. The system was presented to the Mexican Institute of Industrial Property, at March 15, 1996 and the patent was conceded April 19, 2007 (#245717). PMID:18669306

Martínez, Genaro Rico; Domínguez, Víctor H; Muller, José Antonio; Cedillo, Ernesto A Delgado; Roa, Josué Antonio Miranda; Montoya, Roberto C


An Evaluation of Retrieved UHMWPE Hip Joint Cups  

Microsoft Academic Search

In this study it is demonstrated that the combined chemical and mechanical influences of the implant situation cause property changes of ultra-high-molecular-weight polyethylene (UHMWPE) hip joint cups. Nearly 250 loosened hip cups, retrieved 3 weeks to 14 years after implantation, were investigated. The clinical long-term behavior of various shaped polyethylene hip sockets are statistically analyzed. The main damage features were

M. Kurth; P. Eyerer; R. Ascherl; K. Dittel; U. Holz



Curved-stem Hip Resurfacing  

PubMed Central

Hip resurfacing is an attractive concept because it preserves rather than removes the femoral head and neck. Most early designs had high failure rates, but one unique design had a femoral stem. Because that particular device appeared to have better implant survival, this study assessed the clinical outcome and long-term survivorship of a hip resurfacing prosthesis. Four hundred forty-five patients (561 hips) were retrospectively reviewed after a minimum of 20 years’ followup or until death; 23 additional patients were lost to followup. Patients received a metal femoral prosthesis with a small curved stem. Three types of acetabular reconstructions were used: (1) cemented polyurethane; (2) metal-on-metal; and (3) polyethylene secured with cement or used as the liner of a two-piece porous-coated implant. Long-term results were favorable with the metal-on-metal combination only. The mean overall Harris hip score was 92 at 2 years of followup. None of the 121 patients (133 hips) who received metal-on-metal articulation experienced failure. The failure rate with polyurethane was 100%, and the failure rate with cemented polyethylene was 41%. Hip resurfacing with a curved-stem femoral component had a durable clinical outcome when a metal-on-metal articulation was used. Level of Evidence: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.



Snapping Hip  


... muscle to move smoothly over bone. ( Left ) This front-view of the hip and thigh shows musculature most often associated with snapping hip: the iliotibial band, rectus femoris tendon, and iliopsoas muscle. ( Right ) The biceps femoris hamstring muscle travels under the ...


Polyetheretherketone (PEEK) Spacers for Anterior Cervical Fusion: A Retrospective Comparative Effectiveness Clinical Trial  

PubMed Central

Background: Anterior cervical decompression and fusion (ACDF) is the standard surgical treatment for radiculopathy and myelopathy. Polyetheretherketone (PEEK) has an elasticity similar to bone and thus appears well suited for use as the implant in ACDF procedures. The aim of this study is to examine the clinical and radiographic outcome of patients treated with standing alone PEEK spacers without bone morphogenic protein (BMP) or plating and to examine the influence of the different design of the two spacers on the rate of subsidence and dislocation. Methods: This retrospective comparative study reviewed 335 patients treated by ACDF in a specialized urban hospital for radiculopathy or myelopathy due to degenerative pathologies. The Intromed PEEK spacer was used in 181 patients from 3/2002 to 11/2004, and the AMT SHELL spacer was implanted in 154 patients from 4/2004 to 12/2007. The follow-up rate was 100% at three months post-op and 82.7% (277 patients) at one year. The patients were assessed with the Japanese Orthopedic Association (JOA) questionnaire and radiographically. Results: At the one-year follow-up there were 118/277 patients with an excellent clinical outcome on the JOA, 112/277 with a good outcome, 20/277 with a fair outcome, and 27/277 with a poor outcome. Subsidence was observed in 13.3% of patients with the Intromed spacer vs 8.4% of the patients with the AMT SHELL. Dislocation of the spacer was observed in 10 of the 181 patients with Intromed spacers but in none of the 154 patients with Shell spacers. Conclusion: The study demonstrates that ACDF with standing alone PEEK cages leads to excellent and good clinical outcomes. The differences we observed in the subsidence rate between the two spacers were not significant and cannot be related to a single design feature of the spacers.

Lemcke, Johannes; Al-Zain, Ferass; Meier, Ullrich; Suess, Olaf



Spacer grid cell fixture system  

SciTech Connect

A weld fixture for receiving and aligning the fuel rod contact points of a nuclear fuel bundle spacer grid is disclosed. Two plates are provided with intersecting unequally spaced slots that define polygons on one side of each plate. Both plates have bores therethrough substantially at the slot intersections and in the slots adjacent the outer edges of the plates. Bores are provided through both plates in polygons that correspond to fuel assembly guide tube and instrument tube locations. These positions receive guide cell pins during use, some of which are hollow and are used to bolt the plates together over the spacer grid strips. Bores in each plate through the defined polygons receive alignment pins. Guide rods receive and align the plates through corner bores in each plate. The slots and pins in the facing plates align the critical fuel rod contact points in the spacer grid during the intersection welding process. 19 figs.

Johnson, G. Jr.; King, R.A.; Minnick, E.C. III



Hip Replacement  


... your doctor may recommend other treatments, such as pain medications, physical therapy, exercise, and use of a cane or walker. If these treatments are not enough, hip replacement may be the right option for you. Conditions that can damage the ...


Hip Injuries  

Microsoft Academic Search

A 50-year-old male artistic director of a professional ballet company presents to your office complaining of pain in both\\u000a hips, left worse than right, which has been gradually worsening over the past 2–3 years. He has difficulty demonstrating certain\\u000a movements in class and feels he has lost full range of motion in his hips.

Ana Bracilovi?


Robot-assisted surgery in total hip replacement  

Microsoft Academic Search

Summary  \\u000a The most important prerequisite for permanent fixation of an implant is primary stability. Osteointegration of the implant\\u000a is a major goal in cementless total hip replacement (THR). This means direct contact between bone and implant, leading to\\u000a fixation of the implant in the bone without the interference of fibrous tissue. In addition to the design of the implant,\\u000a the

M. Börner; A. Bauer; A. Lahmer



Comparison of articulating and static spacers regarding infection with resistant organisms in total knee arthroplasty  

PubMed Central

Introduction The result of treatment of infections involving antibiotic-resistant organisms in total knee arthroplasty (TKA) is often poor. We evaluated the efficacy of 2-stage revision in TKAs infected with resistant organisms and compared the clinical outcomes with articulating and conventional static spacers, in terms of both infection control and function. Methods In a prospective manner, from June 2003 to January 2007 selected patients with a TKA infected with resistant organisms were enrolled and treated with 2-stage re-implantation. The 45 patients were divided into 2 groups: group A (23 patients) implanted with the articulating spacers and group S (22 patients) implanted with static spacers. All patients followed the same antibiotic protocols and had the same re-implantation criteria. The efficacy of infection control was evaluated using re-implantation rate, recurrence rate, and overall success rate. The functional and radiographic results were interpreted with the Hospital of Special Surgery (HSS) knee score and the Insall-Salvati ratio. Results With mean 40 (24–61) months of follow-up, 22 of 23 knees were re-implanted in group A and 21 of 22 were re-implanted in group S. Of these re-implanted prostheses, 1 re-infection occurred in group A and 2 occurred in group S. Range of motion after re-implantation, the final functional scores, and the satisfaction rate were better in group A. One third of the patients in group S, and none in group A, had a patella baja. Interpretation After 2-stage re-implantation of TKAs originally infected with resistant organisms, the clinical outcome was satisfactory—and similar to that reported after treatment of TKAs infected with low-virulence strains. Treatment with an articulating spacer resulted in better functional outcome and lower incidence of patella baja.



Indications and results of hip resurfacing  

PubMed Central

The best indication for hip resurfacing is a young active patient with severe hip arthritis, good hip morphology and reasonable bone quality. With revision of either component for any reason as the endpoint, there were 68 revisions in our series of 3,095 consecutive Birmingham Hip Resurfacings (BHR) (1997–2009), including all diagnoses in all ages. This equates to a revision rate of 2.2% and survivorships of 99, 97 and 96% at five, ten and 13 years, respectively. In patients under 55 years with osteoarthritis, the survivorship is 99 and 98% at ten and 13 years. These results provide medium-term evidence that BHR when performed well in properly selected patients offers excellent outcomes and implant survivorship. Small changes to implant materials and design can affect joint function and survivorship significantly as seen from the withdrawal of certain resurfacing devices recently from clinical use. The clinical history of one device cannot be extrapolated to other devices.

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



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


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

Deisenroth, A; Nolte, I; Wefstaedt, P



Is Patient Selection Important for Hip Resurfacing?  

PubMed Central

The optimal implant option for hip arthroplasty in the young, active patient remains controversial. There has been renewed interest for metal-on-metal hip resurfacing due to improved design and manufacturing of implants, better materials, enhanced implant fixation, theoretical advantages over conventional total hip arthroplasty, and recent Food and Drug Administration approval of two devices. Recent studies indicate satisfactory short- and midterm clinical results (1- to 10-year followup) with low complication rates, but there is a learning curve associated with this procedure, a more extensive surgical approach is necessary, and long-term results have yet to be determined. Proper patient selection may help avoid complications and improve patient outcomes. Patient selection criteria in the literature appear based predominantly on theoretical considerations without any consensus on stratifying patient risk. The most commonly reported complications encountered with hip resurfacing include femoral neck fracture, acetabular component loosening, metal hypersensitivity, dislocation, and nerve injury. At the time of clinical evaluation, patient age; gender; diagnosis; bone density, quality, and morphology; activity level; leg lengths; renal function; and metal hypersensitivity are important factors when considering a patient for hip resurfacing. Based on our review, we believe the best candidates for hip resurfacing are men under age 65 with osteoarthritis and relatively normal bony morphology. Level of Evidence: Level V, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Della Valle, Craig J.; Barrack, Robert L.



Range of motion after stemmed total hip arthroplasty and hip resurfacing - a clinical study.  


Range of motion after total hip arthroplasty is becoming an important topic as today's patients present at a younger age and are more active. An effective study design to carry out comparisons of clinical performance between two implants should eliminate patient-related extraneous variables (e.g., age, gender, activity level, among others). The aim of the present study was to compare the range of motion results achieved postoperatively between metalon-metal hip resurfacing (HR) and conventional total hip arthroplasty (THA) in a cohort of bilateral patients implanted with both designs. Thirty-five patients who had undergone bilateral surgery with one hip receiving an HR device and the contralateral hip receiving a THA were retrospectively selected. Sixty-nine percent of the patients were male, and at the time of implantation of the resurfacing device the mean age of the patients was 53 years. The mean follow-up time was 88 months for the hips treated with HR and 96 months for the hips that received a THA. We found no difference in any of the range of motion measurements between HR and THA even after separating the cohort into two groups based on the femoral head size of the THA (femoral heads under 40 mm and femoral heads greater or equal to 40 mm). Our investigation showed that, for most patients, prosthetic design is unlikely to be a limiting factor of range of motion after surgery provided that the positioning of the acetabular component is adequate. PMID:19583550

Le Duff, Michel J; Wisk, Lauren E; Amstutz, Harlan C



Periprosthetic Femoral Fractures Associated With Contralateral Hip Disease  

Microsoft Academic Search

Femoral osteolysis associated with contralateral hip degenerative changes is a risk factor for ipsilateral periprosthetic femoral fracture. We report 5 comminuted proximal shaft fractures around loose femoral implants occurring in patients with both symptomatic femoral lysis and a painful hip on the other side. Our evolving strategy involves timely revision surgery once this pattern is recognized. Once fracture has occurred,

Andrew G. Yun; Lawrence D. Dorr; William T. Long



Concepts of the Modern Ceramic on Ceramic Total Hip Arthroplasty and Early Results  

Microsoft Academic Search

We reviewed the results of 70 total hip replacements utilizing a modern ceramic on ceramic total hip prosthesis in 60 patients. The age of the selected patients ranged from 25 to 76 years (mean, 46 years). The diagnoses at the time of implantation were osteoarthritis (33 patients), avascular necrosis (29 patients), developmental hip dysplasia (four patients), rheumatoid arthritis (one), and



Hip artroplasty: A transient reason not to be pregnant  

Microsoft Academic Search

Metal implants corrode and release metal ions, cobalt and chromium, which, in turn, may cause systemic toxicity, mostly in the first few months from implantation of metal-on-metal hip arthroplasty. At the time of delivery, the placenta reduces the passage of cobalt and chromium ions released from metal-on-metal prosthesis. From a biomechanical view point, hip replacement should not be considered a

Nicola Maffulli; Angelo Del Buono; Vincenzo Denaro


Results of hip resurfacing  

PubMed Central

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

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



Hip Fracture Prevention  


... Copyright 2013 American Academy of Orthopaedic Surgeons Hip Fracture Prevention Hip fractures are breaks in the thighbone (femur) just below ... and older. Women are especially vulnerable to hip fractures. According to 2010 data from the National Hospital ...


Influence of Prosthetic Design on Squeaking After Ceramic-on-Ceramic Total Hip Arthroplasty  

Microsoft Academic Search

Squeaky ceramic-on-ceramic (COC) total hips have received much recent publicity, and implant design may be implicated. We reviewed 270 consecutive COC total hip arthroplasties in 233 patients comparing 4 implant combinations representing 4 manufacturers. A cohort (n = 45) of Stryker Trident acetabular cups paired with Stryker Accolade femoral stems showed a dramatically higher incidence of “problem squeaking”—defined as always

Todd V. Swanson; David J. Peterson; Raghavendran Seethala; Ryan L. Bliss; Calvin A. Spellmon



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

Microsoft Academic Search

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,

Giuseppe Solarino; Andrea Piazzolla; Claudio M Mori; Lorenzo Moretti; Silvio Patella; Angela Notarnicola



Effects of interspinous spacers on lumbar degenerative disease.  


The present study aimed to evaluate the early effects of interspinous spacers on lumbar degenerative disease. The clinical outcomes of 23 patients with lumbar degenerative disease, treated using interspinous spacer implantation alone or combined with posterior lumbar fusion, were retrospectively studied and assessed with a visual analogue scale (VAS) and the Oswestry Disability Index (ODI). Pre-operative and post-operative interspinous distance, disc space height, foraminal width and height and segmental lordosis were determined. The early effects and complications associated with the interspinous spacers were recorded. The surgical procedures performed with the in-space treatment were easy and minimally invasive. The VAS scores and ODI were improved post-operatively compared with pre-operatively. Significant changes in the interspinous distance, disc space height, foraminal width and height and segmental lordosis were noted. In-space treatment for degenerative lumbar disease is easy and safe, with good early effects. The in-space system provides an alternative treatment for lumbar degenerative disease. PMID:23407682

Zhou, Dong; Nong, Lu-Ming; DU, Rui; Gao, Gong-Ming; Jiang, Yu-Qing; Xu, Nan-Wei



Complex primary total hip arthroplasty.  


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



Alternative bearings in total hip arthroplasty in the young patient.  


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

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



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



Effect of microstructure on the dry sliding friction behavior of CoCrMo alloys used in metal-on-metal hip implants.  


The microstructure and its effect on the friction behavior of a medical grade wrought cobalt-chromium-molybdenum (CoCrMo) alloy for surgical implants were studied in this work. In particular, the effects of compression and carbon (C) content on the above characteristics were analyzed. Increasing amounts of deformation resulted in a decrease in the number of annealing twins in the microstructures. In addition, there was an increase in the volume fraction of the hexagonal closed-packed (HCP) phase due to a strain-induced transformation (SIT) from the metastable face-centered cubic (FCC) phase. The high C (HC) alloy had a lower volume fraction of this SIT phase. Friction studies conducted on these alloys revealed a higher coefficient of friction for the HC alloy and no significant effect of SIT on the friction characteristics. PMID:16080175

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



Total hip arthroplasty.  

PubMed Central

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

Siopack, J S; Jergesen, H E



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


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



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.

Wiig, Monica; Alnehill, Hakan; Berggren, Magnus; Bjornum, Sten; Geijer, Mats; Kopylov, Philippe; Sollerman, Christer



Brief Communication Simple mathematical and computational wear model for ultra-high-molecular-weight polyethylene total hip replacements  

Microsoft Academic Search

Ultra-high-molecular-weight polyethylene is an important constituent of hip implants. Sur- gical revisions are required because of implant loosening and osteolysis (destruction or resorption of bone tissue). We develop a mathematical and a computational model to determine implant life (defined as the time when 20% of the implants operating at a given wear rate is revised) based on wear rates and

K. H. S. Chan; T. Pearce; R. W. Blake; L. Chow; S. Wu; F. Wong; J. Li



Hip Labral Tear  


... a hip labral tear: Overuse. People who participate in sports or other activities that require repeated twisting or ... injuries, and hip arthroscopy in the athlete. Clinics in Sports Medicine. 2006;25:279. Kovacevic D, et al. ...


A Custom Coupling Device of Total Knee and Ipsilateral Total Hip Arthroplasties After Distal Femoral Fracture  

Microsoft Academic Search

The treatment of periprosthetic femoral fractures around long-stemmed hip implants is an orthopedic challenge, which may be complicated by the presence or need for a total knee arthroplasty. Treatment of this fracture when the proximal implant is well fixed and a distal implant is required poses ongoing challenges. Traditional plating and allograft struts have produced variable results, particularly in osteoporotic

Liza E. Osagie; Mathias P. G. Bostrom



Dynamic hip screw blade fixation for intertrochanteric hip fractures.  


PURPOSE. To assess the one-year outcome of a dynamic hip screw (DHS) blade in the treatment of AO/OTA 31-A1 and 31-A2 intertrochanteric hip fractures. METHODS. 35 men and 65 women aged 47 to 100 (mean, 83) years underwent fixation with a DHS blade for A1 (n=47) and A2 (n=53) intertrochanteric hip fractures after a low-energy injury. Patients were operated on within 48 hours of admission. Anteroposterior and lateral radiographs were examined for the tip-apex distance and femoral shortening. Potential complications were looked for, including implant migration, cut-out, loosening, or breakage. Functional outcome was based on the Parker mobility score. RESULTS. The 30-day and one-year mortality rates were 5% and 20%, respectively. At the one-year follow-up, 81 patients were available, and all fractures had healed without varus deformity. The mean tip-apex distance was 14.1 (range, 5.7-31.1; SD, 4.3) mm. The mean femoral shortening was 4.9 (range, 0-20.2; SD, 4.8) mm. The mean Parker score decreased to 3.8 at one-year follow-up from 5.9 before injury (p<0.001). There was one loss of fixation secondary to a non-traumatic subcapital fracture at 3 months, for which a bipolar hemiarthroplasty was performed. CONCLUSION. The DHS blade system is effective in treating AO/OTA 31-A1 and 31-A2 intertrochanteric hip fractures and results in a low complication rate. PMID:23255634

Leung, Frankie; Gudushauri, Paata; Yuen, Grace; Lau, Tak-Wing; Fang, Christian; Chow, Shew-Ping



Total hip replacement arthroplasty  

Microsoft Academic Search

A prospective study of 62 total hip replacements performed between February 1970 and December 1972 in 50 patients was carried out. The results were assessed according to the Asaf Harofe Hip Evaluation System. There were excellent and good results in 89% of hips. Failures occured in 11% and were due to individual cases of loosening of the femoral component, loosening

D. H. Gershuni; A. Axer; D. Segal; N. Halperin



Vacuum-assisted closure in the treatment of early hip joint infections  

PubMed Central

The aim of the present study was to evaluate the efficacy of the vacuum-assisted closure (V.A.C.) system in the treatment of early hip joint infections. 28 patients (11 m / 17 f; mean age 71 y. [43-84]) with early hip joint infections have been treated by means of the V.A.C.-therapy. At least one surgical revision [1-7] has been unsuccessfully performed for infection treatment prior to V.A.C. - application. Pathogen organisms could have been isolated in 22/28 wounds. During revision, cup inlay and prosthesis head have been exchanged and 1-3 polyvinylalcohol sponges inserted into the wound cavity/ periprosthetically at an initial continuous pressure of 200 mm Hg. Postoperatively, a systemic antibiosis was given according to antibiogram. 48-72 h after surgery an alteration from haemorrhagic to serous fluid was observed in the V.A.C.-canister. Afterwards, the pressure was decreased to 150 mm Hg and remained at this level till sponge removal. After a mean period of 9 [3-16] days the inflammation parameters have been retrogressive and the sponges were removed. An infection eradication could be achieved in 26/28 cases. In the two remaining cases the infected prosthesis had to be explanted and a gentamicin-vancomycin-loaded spacer has been implanted, respectively. At a total mean follow-up of 36 [12-87] months no reinfection or infection persistence was observed. The V.A.C.-system can be a valuable contribution in the treatment of early joint infections when properly used. Indications should be early infections with well-maintained soft-tissues for retention of the negative atmospheric pressure.

Kelm, Jens; Schmitt, Eduard; Anagnostakos, Konstantinos



Cochlear Implants  


... Medical Devices Products and Medical Procedures Implants and Prosthetics - Section Contents Menu Products and Medical Procedures Implants and Prosthetics Cochlear Implants What is a Cochlear Implant? Benefits ...


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



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



Congenital hip disease in adults: terminology, classification, pre-operative planning and management.  


This paper reviews the current knowledge relating to the management of adult patients with congenital hip disease. Orthopaedic surgeons who treat these patients with a total hip replacement should be familiar with the arguments concerning its terminology, be able to recognise the different anatomical abnormalities and to undertake thorough pre-operative planning in order to replace the hip using an appropriate surgical technique and the correct implants and be able to anticipate the clinical outcome and the complications. PMID:20595107

Karachalios, T; Hartofilakidis, G



The Exeter™ Universal Hip in Patients 50 Years or Younger at 10–17 Years’ Followup  

Microsoft Academic Search

The Exeter™ Universal hip (Stryker Inc., Newbury, UK) has reported survival rates of 91.74% at 12 years in all patients with\\u000a reoperation as an endpoint. However, its performance in younger patients has not been fully established. We reviewed survivorship\\u000a and the clinical and radiographic outcomes of this hip system implanted in 107 patients (130 hips) 50 years old or younger\\u000a at the

Simon C. Lewthwaite; Ben Squires; Graham A. Gie; Andrew J. Timperley; Robin S. M. Ling



Development of metal/metal hip resurfacing.  


This author's development of metal/metal hip resurfacing began in 1989, with the first patient implantation in February 1991. In the first three years a pilot study identified optimum fixation as hydroxyapatite coated uncemented cups and cemented femoral components. From March 1994 hybrid fixed components have been used. These implants have generally been satisfactory with respect to fixation but high wear of the bearing, metallosis and osteolysis have been seen with some components inserted during 1996, a period during which the metal microstructure was altered by the heat processes, hot isostatic pressing and solution heat treatment. The Birmingham Hip Resurfacing was developed taking account of experience with earlier resurfacing designs. This implant employs hybrid fixation with a porous ingrowth acetabular component and has an as-cast metal microstructure having had no post casting heat treatments. During the past 4 years the author has performed over 1,000 Birmingham Hip Resurfacingís with a total failure rate of less than 1.0%.  PMID:24030583

McMinn, D J W



The effect of abductor muscle and anterior-posterior hip contact load simulation on the in-vitro primary stability of a cementless hip stem  

PubMed Central

Background In-vitro mechanical tests are commonly performed to assess pre-clinically the effect of implant design on the stability of hip endoprostheses. There is no standard protocol for these tests, and the forces applied vary between studies. This study examines the effect of the abductor force with and without application of the anterior-posterior hip contact force in the in-vitro assessment of cementless hip implant stability. Methods Cementless stems (VerSys Fiber Metal) were implanted in twelve composite femurs which were divided into two groups: group 1 (N = 6) was loaded with the hip contact force only, whereas group 2 (N = 6) was additionally subjected to an abductor force. Both groups were subjected to the same cranial-caudal hip contact force component, 2.3 times body weight (BW) and each specimen was subjected to three levels of anterior-posterior hip contact load: 0, -0.1 to 0.3 BW (walking), and -0.1 to 0.6 BW (stair climbing). The implant migration and micromotion relative to the femur was measured using a custom-built system comprised of 6 LVDT sensors. Results Substantially higher implant motion was observed when the anterior-posterior force was 0.6BW compared to the lower anterior-posterior load levels, particularly distally and in retroversion. The abductor load had little effect on implant motion when simulating walking, but resulted in significantly less motion than the hip contact force alone when simulating stair climbing. Conclusions The anterior-posterior component of the hip contact load has a significant effect on the axial motion of the stem relative to the bone. Inclusion of the abductor force had a stabilizing effect on the implant motion when simulating stair climbing.



Movement Mapping as dynamic preoperative surgical planning in total hip replacement  

Microsoft Academic Search

The purpose of the present study was to develop and present a computer program for preoperative simulation of implant components placement in total hip alloarthroplasty, and its influence on the possible range of motion (ROM). We evaluated a computer simulation for preoperative estimation of range of motion (movement mapping) in total hip replacement. The computer program was based on Borland

J. Jerosch; A. Weipert; S. Hanusek; M. Schneppenheim



The Mennen femoral plate for fixation of periprosthetic femoral fractures following hip arthroplasty  

Microsoft Academic Search

Periprosthetic fractures can be treated by various methods. The Mennen femoral plate used to be a common implant in our region to stabilise periprosthetic femoral fractures following hip arthroplasty.This device has been used in 16 patients in our region from three different centres. The periprosthetic femoral fractures occurred approximately 7 years after the hip arthroplasty procedure. After stabilisation of the

Sashin Ahuja; S Chatterji



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



Comparison of Polyethylene Wear Associated with Cobalt-Chromium and Zirconia Heads After Total Hip Replacement  

Microsoft Academic Search

Background: A ceramic femoral head is an alternative to a metal femoral head for the bearing surface of total hip ar- throplasty. The purpose of this study was to compare polyethylene wear in patients who had undergone bilateral total hip arthroplasty with implants that differed only with regard to the material used for the femoral head: a zirconia head was



Hip Implant Corrosion Mechanisms and Effects  

Center for Biologics Evaluation and Research (CBER)

Text Version... kI = ? ? m is metal ion levels in urine, I is the ... Fretting can INITIATE crevice corrosion ... Negative voltage excursions result from MAC and may lead ... More results from


Hip arthroplasty for failed treatment of proximal femoral fractures.  


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



Hip arthroplasty for failed treatment of proximal femoral fractures  

PubMed Central

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?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.

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



Separator-spacer for electrochemical systems  


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)



What Is a Hip Replacement?  


... a hip joint and replaces them with new, man-made parts. The goals of this surgery are to: Relieve pain Help the hip joint work better Improve walking and other movements. Who Should Have Hip Replacement Surgery? How Should ...


Imaging of hip arthroplasty.  


The imaging evaluation of the prosthetic hip begins with radiography, but arthrography, aspiration, scintigraphy, sonography, CT and MR imaging all have roles in the evaluation of the painful prosthesis. This article will review the appearance of normal hip arthroplasty including hemiarthroplasty, total arthroplasty, and hip resurfacing, as well as the appearances of potential complications such as aseptic loosening and osteolysis, dislocation, infection, periprosthetic fracture, hardware failure, and soft tissue abnormalities. PMID:21530121

Miller, Theodore T



Reasons for revision hip surgery: a retrospective review.  


The purpose of this study was to determine the indications for contemporary revision hip surgery in a consecutive series of patients. We retrospectively reviewed the clinical records and radiographs of 439 revision hip surgeries done between 1996 and 2003. Fifty-five percent of the surgeries were for aseptic loosening, 14% were for instability, 13% were for osteolysis around a well-fixed implant, 7% were for infection, 5% were for periprosthetic fracture, 3% were for conversion of a hemiarthroplasty, 1% was for psoas impingement, 1% was for loose recalled implants, and 1% was for implant fracture. As expected, aseptic loosening was the most common reason for revision surgery. Instability was a common reason for early revision whereas revision for osteolysis around a well-fixed implant was a more common reason for late revision. PMID:15577486

Clohisy, John C; Calvert, George; Tull, Frank; McDonald, Douglas; Maloney, William J



Hip fracture - discharge  


Inter-trochanteric fracture repair - discharge; Subtrochanteric fracture repair - discharge; Femoral neck fracture repair - discharge; Trochanteric fracture repair - discharge; Hip pinning surgery - ...


Dental Implants  


Dental Implants Did you know that dental implants are frequently the best treatment option for replacing missing teeth? ... implants can last a lifetime. Anatomy of a Dental Implant A dental implant designed to replace a single ...


Development and validation of a navigational guidance system for acetabular implant placement  

Microsoft Academic Search

During the past year our group has been developing HipNav, a system which helps surgeons determine optimal, patient-specific acetabular implant placement and accurately achieve the desired implant placement during surgery. HipNav includes three components: a pre-operative planner, a range of motion simulator, and an intra-operative tracking and guidance system. The goals of the current HipNav system are to: 1) reduce

David A. Simon; Branislav Jaramaz; Mike Blackwell; F. Morgan; Anthony M. Digioia; E. Kischell; Bruce Colgan; Takeo Kanade



CFP prosthetic stem in mini-invasive total hip arthroplasty  

Microsoft Academic Search

Mini-invasive surgery preserves soft tissues and bone as much as possible, in order to minimize surgical trauma and blood loss, and hasten functional recovery. Hip replacement carried out with the CFP prosthetic stem (Waldemar Link, Hamburg, Germany) allows preservation of the femoral neck; furthermore, the implantation can be performed mini-invasively through a small incision. This paper reports the short- and

F. Pipino



Metal release from hip prostheses: cobalt and chromium toxicity and the role of the clinical laboratory.  


Individuals with advanced hip disease suffer from pain, impaired hip function, and decreased quality of life. Roughly one million metal-on-metal (MoM) hip prostheses have been implanted worldwide in order to ameliorate these issues. While most MoM hip replacements are successful, some patients suffer from serious adverse effects secondary to the release of metal debris due to implant wear and corrosion. MoM hip prostheses are comprised predominantly of cobalt and chromium, and the serum concentration of these metal ions has been shown to correlate with both implant wear and the accumulation of metal debris in the periprosthetic tissue. Consequently, measurement of cobalt and chromium concentrations may be useful in the assessment of implant function and the potential for adverse effects in the follow-up of patients with MoM hip prostheses. The purpose of this Mini Review is to describe the adverse biological consequences of metal release from hip prostheses, provide an overview of the clinical utility of cobalt and chromium measurement and the current recommendations for testing, and alert laboratorians and physicians to the many challenges associated with measuring these metal ions. PMID:23023696

Campbell, Jonathon R; Estey, Mathew P



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.



In vivo transcription of rDNA spacers in Drosophila.  

PubMed Central

The sequence-nonhomologous rDNA spacers of D. melanogaster and D. virilis exhibit remarkably similar organizations and transcription capabilities. In spacers of both species, tandemly repeated sequences are present upstream of the beginning of the pre-rRNA coding region, and the repeats are capable of transcriptional activity. Short, nuclear transcripts homologous to the spacer repeats have been identified by S1 nuclease protection experiments and by northern blot analyses. Although spacer transcripts are rare in steady state RNA populations, the presence of multiple promoter elements may suggest a regulatory role for rDNA spacers. Images

Murtif, V L; Rae, P M



Spacer performance in the cationic isotachophoresis of proteins.  


Performance of narrow range ampholytes and a discrete spacer mixture is evaluated for improved protein separations by cationic isotachophoresis. A spacer mixture containing 22 cations is developed and relative step heights of components are presented. Different ampholytes and the discrete spacer give unique results for test mixtures of model proteins. While no spacer mixture can be universally recommended, discrete spacers offer the possibility of optimizing separations based on component selection. An example of optimizing a separation of five model proteins is presented. PMID:2738141

Stover, F S



Preclinical investigations towards the first spacer gel application in prostate cancer treatment during particle therapy at HIT  

PubMed Central

Background The application of spacer gel represents a promising approach to reliably spare the rectal frontal wall during particle therapy (IJROBP 76:1251-1258, 2010). In order to qualify the spacer gel for the clinical use in particle therapy, a variety of measurements were performed in order to ensure the biological compatibility of the gel, its physical stability during and after the irradiation, and a proper definition of the gel in terms of the Hounsfield Unit (HU) values for the treatment planning system. The potential for the use of the spacer gel for particle therapy monitoring with off-line Positron Emission Tomography (PET) was also investigated. Results The spacer gel implanted to the prostate patient in direct neighbourhood to the clinical target volume does not interfere with the particle therapy treatment planning procedure applied at Heidelberg Ion Beam Therapy Centre (HIT). The performed measurements show that Bragg-peak position of the particles can be properly predicted on the basis of computed tomography imaging with the treatment planning system used at HIT (measured water equivalent path length of 1.011 ±0.011 (2?), measured Hounsfield Unit of 28.9 ±6.1 (2?)). The spacer gel samples remain physically unchanged after irradiation with a dose exceeding the therapeutic dose level. The independently measured Bragg-Peak position does not change within the time interval of 10 weeks. Conclusions As a result of the presented experiments, the first clinical application of spacer gel implant during prostate cancer treatment with carbon ions and protons was possible at HIT in 2012. The reported pre-clinical investigations demonstrate that use of spacer gel is safe in particle therapy in presence of therapy target motion and patient positioning induced particle range variations. The spacer gel injected between prostate and rectum enlarge the distance between both organs, which is expected to clinically significantly decrease the undesirable exposure of the most critical organ at risk, i.e. rectal frontal wall. Further research on the composition of spacer gel material might lead to additional clinical benefits by validation of particle therapy of prostate via post-therapeutic PET-imaging or by patient positioning based on the gel as a radio-opaque marker.



Surgical Procedure Profile in a Comprehensive Hip Surgery Program  

PubMed Central

Surgical management of hip disease in adolescents and young to middle-aged adults is rapidly evolving, and a variety of operative techniques are needed to provide comprehensive care. The purpose of this study was to determine the utilization of surgical procedures and recent changes in procedure utilization in a comprehensive hip surgery program. We performed a retrospective review of 983 hip procedures in 854 patients performed over a seven year time period. The average patient age was 37.4 years (range 10-55). Five hundred fifty-six procedures were performed in female patients and 427 in male patients. Total hip arthroplasty (32.9%), hip arthroscopy (25.1%), and periacetabular osteotomy (13.1%) were the most common surgical procedures. Techniques utilized less often included osteochondroplasty of the femoral head-neck junction (7.9%), hip implant revisions (7.9%), and proximal femoral osteotomy (4.1%). Uncommon procedures included core decompression (2.2%), soft tissue releases (1.2%), femoral head resurfacing (0.6%), arthrodesis (0.3%,) and Chiari pelvic osteotomy (0.2%). The most dramatic changes in utilization over the seven year time period included a marked increase in hip arthroscopies and osteochondroplasties of the femoral head-neck junction. These data underscore the variety of surgical techniques needed to treat this patient population, and emphasize an expanding role for nonarthroplasty surgical interventions.

Clohisy, John C; Curry, Madelyn C; Fejfar, Shane T; Schoenecker, Perry L



Anatomical hip model for the mechanical testing of hip protectors  

Microsoft Academic Search

An anatomical hip model has been developed to simulate the impact load on the hip of a falling person wearing a hip protector. The hip consists of an artificial pelvis made of aluminium, linked by a ball-and-socket joint to an anatomically shaped steel femur (thigh bone). The femur is embedded in silicone material with a hip-shaped surface to allow realistic

Siegfried Derler; A. B. Spierings; K.-U. Schmitt



Pathogenic organisms in hip joint infections  

PubMed Central

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

Geipel, Udo



Concerns with modularity in total hip arthroplasty.  


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



Ceramic-on-Ceramic versus Ceramic-on-Polyethylene Bearings in Total Hip Arthroplasty: Results of a Multicenter Prospective Randomized Study and Update of Modern Ceramic Total Hip Trials in the USA  

Microsoft Academic Search

One reason why otherwise well functioning total hip replacements have a finite service life is eventual aseptic Ioosening of the implants because of osteolysis induced by wear particles from the artificial bearing. Pain and osteolysis from wear debris can manifest even in the absence of aseptic Ioosening. Total hip replacements with ceramic-on-ceramic articulations have shown less wear both in vitro

B. S. Bal; T. J. Aleto; J. P. Garino; A. Toni; K. J. Hendricks


Percutaneous treatment of lumbar compression fracture with canal stenosis and neurogenic intermittent claudication: combining kyphoplasty and interspinous spacer.  


Vertebral compression fractures (VCFs) can cause symptomatic spinal canal stenosis secondary to posterior wall retropulsion. This report describes four patients with VCF and lumbar stenosis secondary to posterior wall retropulsion who were treated with combined kyphoplasty and percutaneous interspinous spacer (IS) placement. Clinical and imaging follow-up ranged from 12-36 months. Outcomes were favorable. Combined kyphoplasty and percutaneous IS implant represents a minimally invasive, safe, and efficient option to treat VCF with symptomatic spinal stenosis. PMID:23101915

Bonaldi, Giuseppe; Cianfoni, Alessandro



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



Failure of Larger-Diameter Metal-on-Metal Total Hip Arthroplasty Resulting from Anterior Iliopsoas Impingement  

Microsoft Academic Search

Anterior iliopsoas impingement is a recognized cause of persistent groin pain after total hip arthroplasty. We report 3 patients with failed total hip arthroplasties resulting from anterior iliopsoas and capsular impingement secondary to a metal femoral ball with a diameter larger than the native femoral head. All patients had the same implant design. Resolution of symptoms occurred in all patients

James A. Browne; David J. Polga; Rafael J. Sierra; Robert T. Trousdale; Miguel E. Cabanela



Late Prosthetic Hip Joint Infection with Actinomyces israelii in an Intravenous Drug User: Case Report and Literature Review  

Microsoft Academic Search

Late infections with Actinomyces israelii have been described for prosthetic hip joints but not in association with intravenous drug use. We present a case of a 43-year-old intravenous drug user who developed A. israelii infection in connection with a hip prosthesis 11 years after implantation, and we review four previously reported cases of Actinomyces prosthetic joint infections. CASE REPORT A

Rana Zaman; Mujahed Abbas; Eileen Burd



Assessment of accuracy and reliability in preoperative templating for hip resurfacing arthroplasty.  


The current study investigated the accuracy and reliability of hip resurfacing component selection based on digital preoperative templating. Four surgeons made a template of preoperative radiographs on 2 occasions for acetabular and femoral components in 50 randomly selected hip resurfacing patients. Component selection reliability was variable among surgeons (kappa = 0.16-0.73) and fair between surgeons (kappa = 0.23-0.32). The average percentage of agreement for the acetabular component was 47% (range, 32%-64%) and for the femoral component was 54% (range, 38%-70%). Surgeons tended to underestimate implant size if the correct implant was not chosen (acetabular, 29%; femoral, 32%). Selection of an undersized femoral component may lead to femoral neck notching or varus implant alignment. This study emphasizes the need for intraoperative verification of preoperative templating results to ensure optimal implant selection in hip resurfacing. PMID:19251390

Olsen, Michael; Gamble, Patrick; Chiu, Mark; Tumia, Nezar; Boyle, Richard A; Schemitsch, Emil H



Cormet Hip Resurfacing Prosthesis  

Center for Biologics Evaluation and Research (CBER)

Text Version... June 27 and 28, 2012 Cormet Hip Resurfacing Prosthesis Page 2. ... (Hydroxyapatite) over unalloyed titanium coating Device Description ... More results from


Ultrasound: Infant Hip  


... The technician will then move a small wand (transducer) over the gel. The transducer emits high-frequency sound waves and a computer ... a slight pressure on the hip as the transducer is moved, and the gel may feel wet ...


540 Trans oro Pharyngeal Spacer for Inhalers  

PubMed Central

Background Many of the patients suffering from bronchial asthma (BA) and COPD do not use the inhalers properly inspite of adequate education, resulting in inadequate relief. The external spacer (es) with the inhaler needs an inspiratory rate of 25 ltsmt, not portable and costly. Also the aerosol deposition in the airways ranges from 20 to 40%only. Wheezy patients with inadequate usage of the inhalers, cleft lip and cleft palate, geriatric and odentulous category, obese asnd short neck individuals cannot take the inhalers properly. Hence an inspiratory effort independent-transoropharyngeal spacer (Tops) is developed. Inclusion criteria 1. Adults and children above 5 years of age of both sex. 2. Subjects of bronchospasm with or without comorbid cleft lip and cleft palate. Exclusion criteria 1. Patient with exaggerated gag reflux. 2. Unconscious patient. Apparatus 1. Mini Wright's Pefr Meter. 2. Tops: it is a patented device made up of ethylene vinyl acetate copolymer. It has a receptacle for the inhalers, body with an angulation of 110 degrees bent and a curved tail piece, 150 degrees. Length - 10 cms, internal diameter - 10 mm, snugly fitting in the oropharynx, the distal end overlying the epiglottis as seen in mri pharynx. 3. External spacer. 4. Salbutamol mdi. Procedure One hundred and fifty subjects (m: f 95:56), within the age range of 8 to 81 years were enrolled in the study from 1st Feb 2007 to 1 April 2007. Pefr was measured before and after the aerosol delivery using tops and external spacer as conduits at ampm respectively, coinsiding with diurnal variation of bronchomotor tone. Four children had cleft lip and palate. Results The pefr in lt/mt was grades as: below 200l (severe), 200 to 300 (moderate), 300 to 400 (mild), above 400 (very mild). There were 80 (53%) in the severe, 50 (33%) in moderate,15 (10%) mild, 5 (4%) very mild. With the tops + inhaler 80% had improvement by 60% increment of pefr (one puff-100 mcg). With the es (2 puffs–200 mcg) plus inhaler there was only 10% increment. Thus the improvement with the former was significant (P = 0.9641, r = 0.9660); radioactive isotope scan showed 80% deposition in the lungs with tops versus es (40%). A lateral study found advantage over rotahaler and nebulizer. Conclusion Inhaler with tops is a better device for delivering aerosol.

Rao, Prabhakar PV; Kashyap, LP; Kishan, Hari



Epidemiology of hip fractures  

Microsoft Academic Search

There were an estimated 1.66 million hip fractures worldwide in 1990. According to the epidemiologic projections, this worldwide annual number will rise to 6.26 million by the year 2050. This rise will be in great part due to the huge increase in the elderly population of the world. However, the age-specific incidence rates of hip fractures have also increased during

P. Kannus; J. Parkkari; H. Sievänen; A. Heinonen; I. Vuori; M. Järvinen



Hip arthroscopy for extra-articular hip disease.  


The increasing popularity and success of hip arthroscopy has led to the development of related techniques for treating hip pathologies external to the joint proper. These minimally invasive endoscopic procedures serve in a diagnostic role to complement clinical evaluations and offer a therapeutic alternative to traditional open techniques. The indications for extra-articular hip endoscopy continue to expand. Recent literature describes applications for treating greater trochanteric pain syndrome, internal snapping hip, deep gluteal syndrome, and subspine impingement and for diagnosing and treating extra-articular sources of hip pain in patients who have undergone hip arthroplasty. PMID:23881610

Reich, Michael S; Shannon, Claire; Tsai, Eugene; Salata, Michael J




Microsoft Academic Search

The state-of-the-art porous coatings become more and more popular in uncemented prostheses to make bone grow into implants for biological fixation. In this paper, graded cellular structures are proposed for uncemented prostheses to enhance stability on implant-bone interfaces. As an example study, the authors develop a new acetabular implant with gradient porosity for hip replacement. A gradient porous acetabular component

Hongqing Vincent Wang; Scott R. Johnston; David W. Rosen


Total hip replacement in young adults with hip dysplasia  

PubMed Central

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



Variations in transcriptional activity of rDNA spacer promoters.  

PubMed Central

We have compared the DNA sequences of several different examples of the duplicated polymerase I promoters that are found in rDNA spacers of Xenopus laevis. Although different spacers exhibit different amounts of transcription in vivo, this does not seem to be due to DNA sequence differences between spacer promoters. We have found that several different spacer promoters when subcloned and injected into oocytes exhibit similar promoter activities when transcription is assayed by primer extension analysis. Moreover, the activity of these spacer promoters is the same as that of a co-injected gene promoter. The equivalence of spacer promoter activity and gene promoter activity was also found when rDNA plasmids containing intact spacers were injected into oocytes and transcription assayed by primer extension. This is in contrast to (1) the inactivity normally exhibited by the promoters of endogenous spacers in oocytes, (2) the relative inactivity of spacer promoters found when transcription of the same rDNA plasmids is assayed by electron microscopy. Images

Morgan, G T; Roan, J G; Bakken, A H; Reeder, R H



Properties of cellulase immobilized on agarose gel with spacer  

SciTech Connect

Cellulase produced by fungus Trichoderma viride was immobilized on agarose beads (Sepharose 4B) activated by cyanogen bromide and also on activated agarose beads that contained spacer arm (activated Ch-Sepharose 4B and Affi-Gel 15). The CMCase activity retained by immobilized cellulase on activated Sepharose containing the spacer tended to be higher than that immobilized without spacer, although the extent of protein immobilization was lower. Also, the higher substrate specificity for cellulase immobilized on beads with spacer was obtained for cellobiose, acid-swollen cellulose, or cellulose powder. The hydrolysis product from their substrates was mainly glucose. 10 references.

Chim-anage, P.; Kashiwagi, Y.; Magae, Y.; Ohta, T.; Sasaki, T.



Small Stem Total Hip Arthroplasty in Hypoplasia of the Femur  

PubMed Central

Total hip arthroplasty in hypoplastic femurs is technically difficult and the incidence of complications and aseptic loosening is relatively high. Cemented, uncemented, off-the-shelf, and custom-made stems all have been advocated in these cases. From 1978 to 1997, we performed 86 total hip arthroplasties in 77 patients with a hypoplastic femur using a cemented, off-the-shelf, small, curved, cobalt-chromium stem. We hypothesized results equaled those of the identical but larger-sized stems in normal-sized femora which were used as comparisons. Clinical and radiographic evaluations were performed. Minimum followup was 4.2 years (mean, 12 years; range, 4.2–20.3 years); mean Harris hip score was 88, and mean hip flexion was 104°. Six stems were revised: four because of aseptic loosening, one after a femoral fracture, and one because of malpositioning. Complications included one perforation and one fracture of the femur, one fracture, one nonunion of the greater trochanter, and one deep infection. Implant survivorship for all hips at 15 years with aseptic revision of the stem as the end point was 90% (confidence interval, 82–99) which equaled results of the larger stems. The small off-the-shelf cemented Weber stem has a high long-term survival and a low complication rate. Survival compares favorably with other small-sized total hip systems. Level of Evidence: Level III, therapeutic study, case-control.

Haverkamp, Daniel; Van der Vis, Harm M.; Besselaar, Philip P.; Marti, Rene K.



Dynamics of hip joint effusion after posterior soft tissue repair in total hip arthroplasty.  


Dislocation after total hip replacement is more common in the early, postoperative period. Postoperative intraarticular haematoma and remaining seroma fluid and/or weakened posterior soft tissue wall may be contributing factors. Our purpose was to compare and follow with sonography the resorption of the postoperative volume of intraarticular fluid/synovial oedema after total hip arthroplasty (THA) with or without posterior soft tissue repair. Thirty-three consecutive patients with hip osteoarthritis were admitted for THA. All of them received the same type of cemented implant. Patients were randomised for posterior soft tissue repair or not. Sonography, measuring the anterior capsular distension, indicating the volume of intraarticular fluid/synovial oedema in the prosthetic hip joints, was performed after six and 12 months in all patients. At six months postoperatively greater capsular distension, i.e., remaining volume of intraarticular fluid/synovial oedema, was observed in the group with posterior soft tissue repair than in the group without. After one year the capsular distension had decreased in both groups and there was no significant difference between the groups. Our results show that posterior soft tissue repair after THA is associated with increased capsular distension during the first six months. After 12 months the volume of intraarticular fluid/synovial oedema is the same with or without posterior soft tissue repair. PMID:16521013

Tarasevicius, Sarunas; Kesteris, Uldis; Kalesinskas, Romas Jonas; Wingstrand, Hans



Dynamics of hip joint effusion after posterior soft tissue repair in total hip arthroplasty  

PubMed Central

Dislocation after total hip replacement is more common in the early, postoperative period. Postoperative intraarticular haematoma and remaining seroma fluid and/or weakened posterior soft tissue wall may be contributing factors. Our purpose was to compare and follow with sonography the resorption of the postoperative volume of intraarticular fluid/synovial oedema after total hip arthroplasty (THA) with or without posterior soft tissue repair. Thirty-three consecutive patients with hip osteoarthritis were admitted for THA. All of them received the same type of cemented implant. Patients were randomised for posterior soft tissue repair or not. Sonography, measuring the anterior capsular distension, indicating the volume of intraarticular fluid/synovial oedema in the prosthetic hip joints, was performed after six and 12 months in all patients. At six months postoperatively greater capsular distension, i.e., remaining volume of intraarticular fluid/synovial oedema, was observed in the group with posterior soft tissue repair than in the group without. After one year the capsular distension had decreased in both groups and there was no significant difference between the groups. Our results show that posterior soft tissue repair after THA is associated with increased capsular distension during the first six months. After 12 months the volume of intraarticular fluid/synovial oedema is the same with or without posterior soft tissue repair.

Kesteris, Uldis; Kalesinskas, Romas Jonas; Wingstrand, Hans



Bone cement implantation syndrome.  


Bone cement implantation syndrome (BCIS) is characterized by hypoxia, hypotension, cardiac arrhythmias, increased pulmonary vascular resistance and cardiac arrest. It is a known cause of morbidity and mortality in patients undergoing cemented orthopaedic surgeries. The rarity of the condition as well as absence of a proper definition has contributed to under-reporting of cases. We report a 59-year-old woman who sustained fracture of the neck of her left femur and underwent an elective hybrid total hip replacement surgery. She collapsed during surgery and was revived only to succumb to death twelve hours later. Post mortem findings showed multiorgan disseminated microembolization of bone marrow and amorphous cement material. PMID:23817399

Razuin, R; Effat, O; Shahidan, M N; Shama, D V; Miswan, M F M



The output of budesonide from spacer devices assessed under simulated breathing conditions  

Microsoft Academic Search

Background: Spacer devices are increasingly used to aid inhalational therapy, and many different devices are available. Patient and spacer size and spacer static charge may affect drug delivery, but the optimum spacer size and method of reducing static charge is not certain. Objective: We sought to determine the output of budesonide from 3 different spacer devices when assessed by using

Peter W. Barry; Chris O’Callaghan



Periprosthetic bone remodelling of a collum femoris preserving cementless titanium femoral hip replacement.  


Total hip arthroplasty represents a major surgical achievement for pain relief and restoration of lifestyle quality due to the joint disease of osteoarthritis. Total hip replacement has evolved over the past 30 years utilising a variety of biocompatible materials, geometric shapes and fixation techniques. The main objective of this study is to investigate the long-term effects of strain adaptive bone remodelling due to the influence of a novel titanium cementless femoral hip replacement. The period of on-growth has been taken into account and the simulation has been run to predict the remodelling behaviour for a 36-month period. The main conclusion from this analysis is that the implant does shield the calcar to a similar degree as other cementless femoral hip designs. It does, however, tend to cause bone to be laid down along its length. This may, in part, be due to the novel geometry of the implant interlocking with and loading the bone. PMID:18651275

Gillies, R M; Kohan, L; Cordingley, R



Hip resurfacing: a technology reborn  

PubMed Central

In recent years there has been a resurgence of interest in the concept of hip resurfacing. Much of this interest has stemmed from the work of McMinn in the West Midlands. Hip resurfacing is now emerging as a viable alternative to conventional hip replacement. In this article, we discuss the conceptual advantages offered by hip resurfacing and review the early clinical results and the ongoing clinical concerns regarding this technology.

Cutts, Steven; Carter, Paul B



Enhancement of exchange bias through a non-magnetic spacer  

Microsoft Academic Search

The magnitude of exchange bias, HE, measured perpendicular to the film plane, can be significantly enhanced by inserting an ultrathin Pt spacer layer between a (Pt\\/Co) multilayer (ML) with perpendicular anisotropy and an antiferromagnetic (AFM) layer. A less pronounced effect is also observed when the spacer is introduced inside the AFM layer, near the FM–AFM interface. The HE enhancement is

J. Sort; F. Garcia; B. Rodmacq; S. Auffret; B. Dieny



[Hip resurfacing arthroplasty].  


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

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



Femoral-head vascularity after hip surface arthroplasty  

PubMed Central

Background Iatrogenic devascularization of the femoral head is as an area of concern following hip resurfacing arthroplasty, with probable implications on short-term failure and long-term survival of the implant. Materials and methods We assessed the vascularity of 25 resurfaced femoral heads in 20 patients by comparison with preoperative and postoperative Tc-99m methylene diphosphonate (MDP) bone scintigraphy images, the postoperative scans being done 9 months after the surgery. Results Eight out of 25 hips (32%) showed <55% of their preoperative uptake at a mean of 9 months after surgery and were categorized as showing reduced vascularity. Conclusion Our study reveals reduction in vascularity of the femoral-head remnant as a frequent occurrence after hip resurfacing. Our study also highlights the role of bone scintigraphy as tool in assessing the vascularity of resurfaced femoral heads.

Kannan, Arun; Bal, Chandra Sekhar; Kumar, Vijay; Mittal, Ravi; Damle, Nishikant



Short stem option for total hip arthroplasty with retained hardware.  


The presence of retained femoral hardware, usually as a consequence of prior orthopedic trauma, has been classically presented as something that must be removed prior to total hip arthroplasty. However, hardware removal is not without risks, including pain, creation of stress risers, and refracture. The authors report a patient with a retained retrograde femoral nail who underwent total hip arthroplasty with a short, neck-preserving femoral stem used to avoid the need for hardware removal. Clinical results at short-term follow-up have been excellent. In the setting of retained hardware, the use of short stems may be a viable treatment option for a well-selected subgroup of patients who require total hip arthroplasty and when the surgeon cannot use standard implants. PMID:24093688

Mont, Michael A; Pivec, Robert; Issa, Kimona; Harwin, Steven F



Management of the 'young' patient with hip disease.  


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

Ritterman, Scott A; Rubin, Lee E



The Influence of Surgical Approach on Outcome in Birmingham Hip Resurfacing  

Microsoft Academic Search

Various approaches have been described for metal-on-metal hip resurfacing. We compared the posterolateral and direct lateral\\u000a approaches for complications, pain, function, and implant survival in the short and medium term for two surgeons in a consecutive\\u000a series of 790 patients (909 hips; July 1997 to July 2004) followed until July 2007. The direct lateral approach group included\\u000a 135 resurfacing procedures

Callum W. McBryde; Matthew P. Revell; Andrew M. Thomas; Ronan B. Treacy; Paul B. Pynsent



DEXA evaluation of total hip arthroplasty with neck-preserving technique: 4-year follow-up  

Microsoft Academic Search

Periprosthetic bone remodeling, and its evaluation, are the keys of long-term survival of cementless total hip arthroplasty. Dual energy X-ray absorptiometry (DEXA) is the most accurate method to measure bone mineral density, evaluating the effects of bone-prosthesis interactions. We studied, 4 years after implantation, 10 patients who underwent total hip arthroplasty with the CFP prosthetic stem and TOP acetabular cup

F. Biggi; F. Franchin; R. Lovato; F. Pipino



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

PubMed Central

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

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



Imaging of hip arthroplasty.  


Imaging studies are central to the evaluation of persistent or recurrent symptoms after hip arthroplasty. The evaluation starts with radiographs and may be followed by arthrography, aspiration, scintigraphy, sonography, computed tomography, and MR imaging. Common etiologies of a painful or dysfunctional hip arthroplasty are mechanical loosening, polyethylene wear-induced osteolysis, adverse local tissue reaction to metal wear products, infection, fractures, heterotopic ossification, tendinopathy, and nerve injury. MR imaging with optimized protocols and dedicated techniques for metal artifact reduction is the most comprehensive imaging modality. In this article, we discuss and illustrate the imaging appearances of these conditions with a focus on the MR imaging evaluation. PMID:23787986

Fritz, Jan; Lurie, Brett; Miller, Theodore T



Imaging the painful hip.  


With the advent of magnetic resonance imaging and, subsequently, magnetic resonance arthrography, the imaging algorithm for hip pain has evolved considerably. Magnetic resonance imaging has supplanted bone scintigraphy as the first line imaging test after conventional radiographs in the setting of suspected occult fracture, transient marrow edema, and osteonecrosis. Computed tomography scanning and magnetic resonance imaging are invaluable for the evaluation of monarticular arthropathies such as pigmented villonodular synovitis and synovial osteochondromatosis. By combining conventional magnetic resonance imaging with capsular distention afforded by arthrography, magnetic resonance arthrography has become the imaging examination of choice for disorders of the acetabular labrum and for the evaluation of articular cartilage at the hip. PMID:12578996

Newberg, Arthur H; Newman, Joel S



Hip Hip 101: A University Level Course Curriculum For Examining Hip Hop In The Modern World  

Microsoft Academic Search

Hip Hop 101 is a university level course curriculum intended for use by college level educators. It serves as a primer on hip-hop history and includes daily lesson plans that use multi-media tools to scaffold student learning. It was produced under the belief that hip-hop (its music and culture) deserve the time and examination as other longstanding disciplines.

David Ma



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



The athlete's hip and groin.  


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

Tammareddi, Kumar; Morelli, Vincent; Reyes, Miguel



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

NASA Astrophysics Data System (ADS)

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.

Jiao, Tifeng; Gao, Fengqing; Zhang, Qingrui; Zhou, Jingxin; Gao, Faming




PubMed Central

Objective To evaluate the clinical performance of the Dynamic Helical Hip System (DHHS) spiral blade relative to the Dynamic Hip Screw (DHS) lag screw. Design Randomized prospective study. Setting One level-2 trauma center and one level-3 trauma center. Patients Fifty-one consecutive patients were recruited into the trial. Inclusion criteria included patients over 50 years of age with AO/OTA 31A1 or 31A2 fracture. Intervention Surgeries were performed by one of 15 participating community orthopaedic surgeons. The patients were randomized to either a DHHS or DHS implant. Follow-up occurred at two weeks and six weeks and then at six-week intervals until healing occurred. Main Outcome Measures Primary outcome variables included sliding of die implant on the final AP radiographs, failure by cut-out and implant failure. Results There were 24 patients in the DHS group and 27 in the DHHS group. There was no difference in age, gender, ASA score, fracture classification or in the quality of reduction measured on the immediate postoperative radiographs (p=0.28) between the two groups. The tip apex distance was 18.7 mm in the DHHS group and 18.5 mm in the DHS group (p=0.40). The DHHS group had average blade sliding of 7.4 mm while the DHS group had an average lag-screw sliding of 7.7 (p=0.45). The DHHS group had two failures by central protrusion of the blade through the femoral head without significant varus collapse or superior migration. One was revised to a DHS and healed, the other was revised to a proximal femoral locking plate, which also failed and eventually required revision to a total hip arthroplasty. Investigation of the implants post failure showed evidence of binding of the blade shaft in the barrel as a mechanism of failure in both cases. No DHS implants cut out in this series, although one patient was revised to a total hip arthroplasty for symptomatic segmental osteonecrosis. Conclusion Both implants performed well in a majority of cases. The higher incidence of failure in the DHHS group is concerning, despite the low numbers. The mechanism of failure of the DHHS implant left adequate bone stock for attempts at revision fixation.

Fitzpatrick, Daniel C; Sheerin, Daniel V; Wolf, Brian R; Wuest, Thomas K



Aseptic loosening of total hip replacement presenting as an anterior thigh mass.  


Aseptic loosening is one of the commonest complications of total hip replacement that can cause pain and instability. The chronic inflammatory response to the wear debris from the polyethylene or metal can cause osteolysis and implant failure. We report a case of aseptic loosening of the hip, presented with a swelling over the anterior thigh without any pain or instability in the joint. This mass was a foreign body granuloma formed secondary to the polyethylene wear debris due to the instability of the polyethylene in the metal shell. The patient underwent successful revision hip arthroplasty after the removal of the foreign body granuloma. PMID:21984313

Gudena, Ravindra; Kuna, Suma; Pradhan, Nikhil



Serum metal ion levels after second-generation metal-on-metal total hip arthroplasty  

Microsoft Academic Search

Introduction  Metal-on-metal bearings for total hip arthroplasty are increasing in popularity. However, metal ion toxicity, metal hypersensitivity,\\u000a and metal carcinogenicity are the causes concern for patients with metal-on-metal hip replacement. We investigated serum levels\\u000a of cobalt and chromium ions in patients with successfully implanted second-generation metal-on-metal total hip arthroplasty\\u000a (THA) using PINNACLE-A (DePuy, Warsaw, IN, USA).\\u000a \\u000a \\u000a \\u000a \\u000a Materials and methods  Thirty-three patients underwent

Takao Imanishi; Masahiro Hasegawa; Akihiro Sudo



Idiopathic chondrolysis of hip.  


An uncommon case of idiopathic chondrolysis of the hip in an 11-year-old girl is reported. It was characterized by clinical presentation, laboratory tests, and imaging techniques. A differential diagnosis is discussed highlighting the radiological features for quick diagnosis. PMID:21607844

Sureka, Jyoti; Jakkani, Ravi Kanth; Inbaraj, Alfred; Panwar, Sanuj



Total hip replacement with an entirely hydroxyapatite-coated prosthesis  

Microsoft Academic Search

The first 100 consecutive entirely hydroxyapatite (HA)-coated hip arthroplasties in 86 patients (mean age, 56.2 years [range, 32–73 years]; female-to-male ratio, 75:25) were followed with standardized radiographs annually up to 5 years. All components developed 100% intimate bone-implant contact, being gradually reduced to 99.5% ± 3.8% by 2 partial periacetabular lines and on the femoral side to 94.0% ± 6.1%

M. Røkkum; A. Reigstad



Inhalational drug delivery from seven different spacer devices.  

PubMed Central

BACKGROUND: A study was performed to determine in vitro the difference in drug output of seven currently available spacer devices when used with different inhaled medications. METHODS: A glass multistage liquid impinger (MSLI) was used to determine the amount of disodium cromoglycate (DSCG, 5 mg), salbutamol (100 micrograms), or budesonide (200 micrograms) obtained in various particle size ranges from metered dose inhalers (MDIs) actuated directly into the MSLI or via one of seven different spacer devices; the Fisonair, Nebuhaler, Volumatic, Inspirease, Aerochamber, Aerosol Cloud Enhancer, and Dynahaler. RESULTS: In particles smaller than 5 microns in diameter the dose of DSCG recovered from the Fisonair and Nebuhaler was 118% and 124%, respectively, of that recovered using the MDI alone. The dose recovered from the smaller volume spacers was 90% (Inspirease), 36% (Aerochamber), 33% (Aerosol Cloud Enhancer), and 21% (Dynahaler) of that from the MDI alone. The Volumatic increased the amount of salbutamol in particles smaller than 5 microns to 117% of that from the MDI, and the Inspirease and Aerochamber spacers decreased it by nearly 50%. The amount of budesonide in small particles recovered after use of the Nebuhaler, Inspirease, and the Aerochamber was 92%, 101%, and 78%, respectively, of that from the MDI alone. CONCLUSIONS: Under the test conditions used, large volume spacers such as the Fisonair, Nebuhaler, and Volumatic delivered significantly more DSCG and salbutamol than the smaller spacers tested. The differences between spacers were less for budesonide than the other medications studied. This study shows that there are significant differences in the amount of drug available for inhalation when different spacers are used as inhalational aids with different drugs. Spacer devices need to be fully evaluated for each drug prescribed for them. Images

Barry, P. W.; O'Callaghan, C.



Total hip arthroplasty in the very young patient.  


The surgical management of end-stage hip disease in patients aged <30 years remains a challenge. Hip-preserving surgical procedures in the setting of advanced disease often do not provide adequate pain relief, but the implications of joint arthroplasty surgery in the very young patient are a matter of concern. The outcome of total hip arthroplasty (THA) in these patients varies, largely because of the wide spectrum of diagnoses associated with hip disease in this group, the complexity of deformities requiring THA, and the need for prolonged durability. The greatest number of THAs in this population is performed for secondary osteoarthritis or osteonecrosis, whereas most reports in the orthopaedic literature have focused on the outcomes of cemented THA in patients with juvenile rheumatoid arthritis. Given the frequent complexity of THA in the very young patient, special attention should be given to preoperative planning, implant selection, and patient education as well as to joint-preservation techniques to facilitate future hip arthroplasty surgery. PMID:22855851

Polkowski, Gregory G; Callaghan, John J; Mont, Michael A; Clohisy, John C



Extra-articular Snapping Hip  

PubMed Central

Context: Snapping hip, or coxa saltans, is a vague term used to describe palpable or auditory snapping with hip movements. As increasing attention is paid to intra-articular hip pathologies such as acetabular labral tears, it is important to be able to identify and understand the extra-articular causes of snapping hip. Evidence Acquisition: The search terms snapping hip and coxa sultans were used in PubMed to locate suitable studies of any publication date (ending date, November 2008). Results: Extra-articular snapping may be caused laterally by the iliotibial band or anteriorly by the iliopsoas tendon. Snapping of the iliopsoas tendon usually requires contraction of the hip flexors and may be difficult to differentiate from intra-articular causes of snapping. Dynamic ultrasound can help detect abrupt tendon translation during movement, noninvasively supporting the diagnosis of extra-articular snapping hip. The majority of cases of snapping hip resolve with conservative treatment, which includes avoidance of aggravating activities, stretching, and anti-inflammatory medication. In recalcitrant cases, surgery to lengthen the iliotibial band or the iliopsoas tendon has produced symptom relief but may result in prolonged weakness. Conclusions: In treating active patients with snapping soft tissues around the hip, clinicians should recognize that the majority of cases resolve without surgical intervention, while being mindful of the potential for concomitant intra-articular and internal snapping hips.



Modular revision for recurrent dislocation of primary or revision total hip arthroplasty 1 1 Benefits or funds were received in partial or total support of the research material described in this article from Zimmer, Warsaw, Indiana; and from a departmental research grant from the University of North Carolina-Chapel Hill  

Microsoft Academic Search

Two surgeons who used the same implants and surgical approach performed 23 revisions for recurrent dislocation of modular total hip arthroplasty (THA) with retention of components. For 17 primary hips, there was a mean of 3.8 (range, 2–10) dislocations before revision. Fifteen hips had exchange of the acetabular liner, 13 had a change in neck length, and 5 had a

Paul F Lachiewicz; Elizabeth Soileau; John Ellis



Good results with cemented total hip arthroplasty in patients between 40 and 50 years of age  

PubMed Central

Background and purpose Total hip arthroplasties in young patients have lower long-term survival rates than in older patients. We evaluated the use of a unique treatment protocol in patients aged between 40 and 50 years. In all cases we used a cemented THA, and for acetabular deficiencies we also used impacted bone grafts together with a cemented cup. Methods In 140 consecutive patients who were between 40 and 50 years of age at index surgery, 168 cemented total hip prostheses were evaluated after a mean follow-up time of 10 (2–19) years. Acetabular deficiencies were reconstructed with wire meshes and impacted bone grafts with a cemented cup (70 hips). During follow-up, 18 patients died (27 hips); in this group 3 hips (3 patients) had been revised. None of the patients were lost to follow-up. In all surviving patients, clinical assessment was performed with hip-score questions and all radiographs were evaluated. Results All clinical questionnaires showed an improved clinical hip score. 29 hips (17%) were revised after a mean of 8 (0.3–18) years. Kaplan-Meier survival analysis showed a survival of 88% (95% CI: 82–94) after 10 years with revision of either component for any reason. Survival with endpoint revision for aseptic loosening of either component was 94% (95% CI: 90–99) after 10 years. Interpretation Cemented implants in young patients have satisfying long-term results. Reconstruction of acetabular deficiencies with impacted bone grafts show promising results.

de Kam, Daniel C J; Gardeniers, Jean W M; Veth, Rene P H



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


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



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

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



Nuclear ribosomal spacer regions in plant phylogenetics: problems and prospects  

Microsoft Academic Search

The nuclear ribosomal locus coding for the large subunit is represented in tandem arrays in the plant genome. These consecutive\\u000a gene blocks, consisting of several regions, are widely applied in plant phylogenetics. The regions coding for the subunits\\u000a of the rRNA have the lowest rate of evolution. Also the spacer regions like the internal transcribed spacers (ITS) and external\\u000a transcribed

Péter Poczai; Jaakko Hyvönen



Dimer Biphenyl Liquid Crystals with Trisiloxane-Containing Spacers  

Microsoft Academic Search

Dimeric biphenyl liquid crystals with trisiloxane containing spacers were studied. Both the tail lengths and the spacer lengths to a central hexamethyltrisiloxane group were varied. In most cases a SmC-phase was found with an anticlinic interlayer relation. One of the compounds appears to have a SmA-phase, which could be a de Vries SmA-phase. A few other compounds show liquid crystalline

Remko Achten; Arie Koudijs; Marcel Giesbers; Antonius T. M. Marcelis; Ernst J. R. Sudhölter



Minimally invasive treatment of lumbar spinal stenosis with a novel interspinous spacer  

PubMed Central

Purpose To assess the safety and effectiveness of a novel, minimally invasive interspinous spacer in patients with moderate lumbar spinal stenosis (LSS). Methods A total of 53 patients (mean age, 70 ± 11 years; 45% female) with intermittent neurogenic claudication secondary to moderate LSS, confirmed on imaging studies, were treated with the Superion® Interspinous Spacer (VertiFlex, Inc, San Clemente, CA) and returned for follow-up visits at 6 weeks, 1 year, and 2 years. Study endpoints included axial and extremity pain severity with an 11-point numeric scale, Zurich Claudication Questionnaire (ZCQ), back function with the Oswestry Disability Index (ODI), health-related quality of life with the Physical Component Summary (PCS) and Mental Component Summary (MCS) scores from the SF-12, and adverse events. Results Axial and extremity pain each decreased 54% (both P < 0.001) over the 2-year follow-up period. ZCQ symptom severity scores improved 43% (P < 0.001) and ZCQ physical function improved 44% (P < 0.001) from pre-treatment to 2 years post-treatment. A statistically significant 50% improvement (P < 0.001) also was noted in back function. PCS and MCS each improved 40% (both P < 0.001) from pre-treatment to 2 years. Clinical success rates at 2 years were 83%–89% for ZCQ subscores, 75% for ODI, 78% for PCS, and 80% for MCS. No device infection, implant breakage, migration, or pull-out was observed, although two (3.8%) patients underwent explant with subsequent laminectomy. Conclusion Moderate LSS can be effectively treated with a minimally invasive interspinous spacer. This device is appropriate for select patients who have failed nonoperative treatment measures for LSS and meet strict anatomical criteria.

Shabat, Shay; Miller, Larry E; Block, Jon E; Gepstein, Reuven



Placing Dental Implants  


Placing Dental Implants Before Placing an Implant Placing the Implants Complications from Surgery Implant Failure When you get implants, more ... Implant Most people are good candidates to get dental implants. You must have enough bone in your jaw ...


The intramedullary hip screw.  


The intramedullary hip screw is a short intramedullary nail with interlocking screws that can be used to treat subtrochanteric and intertrochanteric femur fractures. This nail, which has the biomechanical advantage of being an intramedullary appliance but can be placed percutaneously, is inserted under fluoroscopic control with the patient on a fracture table. Reaming is not usually necessary. In an initial limited series, complication rates are comparable with existing techniques. Possible future concepts and developments are discussed. PMID:10148378

King, D H; Seligson, D



Nuclear reactor spacer grid and ductless core component  


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)



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



Radiostereometric migration analysis of the Lubinus SP II hip stem: 59 hips followed for 2 years.  


The aim of this prospective study was to analyze the migration pattern of the Lubinus SP II hip stem and to evaluate the clinical results. Fifty-nine patients were followed for 2 years. Translational and rotational micromotion of the implant was measured by radiostereometric analysis (RSA) and the Harris hip score (HHS), and the Charnley classification was used to assess the clinical outcome. Although there was a very small, but statistically significant, distal migration of 0.04±0.83 mm, the prosthesis was found stable at 2 years of follow-up. The main migration in this direction took place between 6 months and 1 year. Maximum total point motion (MTPM) showed a mean of 0.99±0.69 mm. Good clinical outcome with HHS results of 42±11 before and 79±16 at 2 years after surgery was observed. The Charnley classification showed increasing additional impairments in the 2-year interval, which is likely to influence the HHS results of future follow-ups. The migration values measured in the present study are far below the thresholds considered clinically relevant in literature. Thus, the conclusion can be drawn that the implant is not at risk for early aseptic loosening. Long-term RSA is required to assess possible late migration. PMID:23912218

Wierer, Thomas; Forst, Raimund; Mueller, Lutz A; Sesselmann, Stefan



Navigated non-image-based positioning of the acetabulum during total hip replacement  

Microsoft Academic Search

We tested the hypothesis that the non-image-based navigation system used in our department was able to measure accurately\\u000a the 3D positioning of the acetabular cup of a total hip replacement (THR) and to increase the accuracy of its implantation\\u000a during THR. We studied 50 consecutive navigated implantations of a THR and compared the intra-operative measurement of the\\u000a cup by the

Jean-Yves Jenny; Cyril Boeri; Jean-Claude Dosch; Marius Uscatu; Eugen Ciobanu



New Solution for Massive, Irreparable Rotator Cuff Tears: The Subacromial "Biodegradable Spacer"  

PubMed Central

Massive, irreparable rotator cuff tears are a source of pain and disability. Although most rotator cuff tears can be completely repaired, a significant number are considered massive and irreparable. Numerous operative techniques have been described for the treatment of these kinds of tears including arthroscopic debridement, biceps tenotomy, tendon transfer, grafting, and reverse arthroplasty. We describe a surgical technique using a biodegradable subacromial balloon spacer (InSpace; OrthoSpace, Kfar Saba, Israel) implanted between the humeral head and acromion that permits smooth, frictionless gliding, restoring the shoulder biomechanics. The technique is easy to perform and is less invasive than the conventional surgical techniques available, and it may potentially serve as a bridging option in patients with massive, irreparable tears who are normally candidates for reverse arthroplasty.

Savarese, Eugenio; Romeo, Rocco



Computer-assisted placement technique in hip resurfacing arthroplasty: improvement in accuracy?  


Freehand positioning of the femoral drill guide is difficult during hip resurfacing and the surgeon is often unsure of the implant position achieved peroperatively. The purpose of this study was to find out whether, by using a navigation system, acetabular and femoral component positioning could be made easier and more precise. Eighteen patients operated on by the same surgeon were matched by sex, age, BMI, diagnosis and ASA score (nine patients with computer assistance, nine with the regular ancillary). Pre-operative planning was done on standard AP and axial radiographs with CT scan views for the computer-assisted operations. The final position of implants was evaluated by the same radiographs for all patients. The follow-up was at least 1 year. No difference between both groups in terms of femoral component position was observed (p > 0.05). There was also no difference in femoral notching. A trend for a better cup position was observed for the navigated hips, especially for cup anteversion. There was no additional operating time for the navigated hips. Hip navigation for resurfacing surgery may allow improved visualisation and hip implant positioning, but its advantage probably will be more obvious with mini-incisions than with regular incision surgery. PMID:17717664

Krüger, S; Zambelli, P Y; Leyvraz, P-F; Jolles, B M



Interface Micromotion of Cementless Hip Stems in Simulated Hip Arthroplasty  

Microsoft Academic Search

Problem statement: The design of hip prostheses has evolved over time due to various complications found after hip replacement surgery. The currently commercially available cementless femoral stems can be categorized into one of three major types, straight cylindrical, tapered rectangu lar and anatomical. Each type proposes a unique concept to achieve primary stability-a major requirement for bone healing process. Virtual

Mohammed Rafiq Abdul Kadir; Nazri Kamsah



The Concept of LDSI (Locally-Differentiated-Scanning Ion Implantation) for the Fine Threshold Voltage Control in Nano-Scale FETs  

Microsoft Academic Search

New Concept of ion implantation technology, namely Locally-Differentiated-Scanning Ion Implantation (LDSI), is suggested for the first time in this report. The Vth variation caused by process non-uniformity in each process variables such as gate Critical Dimension (CD), spacer deposition Uniformity and spacer etch CD, etc, becomes big huddle in scale down and larger diameter wafer. This LDSI technology has been

Min-Yong Lee; S. W. Jin; Y. S. Sohn; S. K. Na; K. B. Rouh; Y. S. Joung; Y. J. Ki; I. K. Han; Y. W. Song; S. W. Park



[Rehabilitation and sport following total hip replacement].  


The number of total hip replacement (THR) surgeries has increased significantly over the last few years and patients undergoing surgery are of decreasing age. In consequence the question of the influencing factors for the survival of artificial hip joints becomes more and more urgent. The expected survival time of an implant is nowadays 15-20 years and it seems that factors for a shorter lifetime are female gender, overweight, younger age and certain indications which led to surgery, such as rheumatoid arthritis or fractures. In the early phase of rehabilitation, measures against dislocation including training of the abductor muscles are most important. Starting rehabilitation programs early after surgery has positive effects on outcome, especially when strengthening programs are included. There are different opinions concerning the question how the lifetime of a THR is influenced by sports activities. However, it seems to have been demonstrated that suitable sports activities have a positive effect and do not necessarily correlate with higher loosening rates after THR. In general, high-impact sports should be avoided. Recommended activities are cycling, swimming, aquajogging, hiking, rowing and dancing. PMID:21607538

Schmitt-Sody, M; Pilger, V; Gerdesmeyer, L



Cochlear Implants  


... and sends them to different regions of the auditory nerve. An implant does not restore normal hearing. ... portions of the ear and directly stimulate the auditory nerve. Signals generated by the implant are sent ...


Delayed catastrophic failure of a ceramic head in hybrid total hip arthroplasty.  


Catastrophic failure of ceramic implants is a rare but known complication of total hip arthroplasty where such implants have been used. We report an unusual case of a 67-year-old woman who underwent bilateral hybrid total hip arthroplasty using ceramic-on-polyethylene bearings. Seven years later, she presented with left-sided hip pain in the absence of any trauma. She was found to have a completely shattered ceramic head, with subsequent erosion of the metal taper of the femoral stem through the polyethylene insert, its metal shell, and into the pelvis. This complicated subsequent revision surgery, as removal of the acetabular component resulted in a large pelvic defect that required an acetabular reinforcement ring and bone grafting. She recovered well after the revision procedure. PMID:18538535

Anwar, Imran; Bhatnagar, Gauraang; Atrah, Salah



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



X-Ray Exam: Hip  


What It Is A hip X-ray is a safe and painless test that uses a small amount of radiation to make images of a person's hip joints ( ... attach to the pelvis). During the examination, an X-ray machine sends a beam of radiation through the ...


In vivo behavior of acrylic bone cement in total hip arthroplasty  

Microsoft Academic Search

Polymethylmethacrylate (PMMA) bone cement serves as the primary fixation material between bone and the prosthetic component in cemented total hip arthroplasty. In vivo degradation of bone cement may lead to a decrease in mechanical properties of PMMA and result in aseptic loosening. However, other factors such as porosity and location of the cement relative to the bone implant interface may

Michael D. Ries; Ernest Young; Laila Al-Marashi; Philip Goldstein; Alexander Hetherington; Timothy Petrie; Lisa Pruitt



Cement mantle fatigue failure in total hip replacement: Experimental and computational testing  

Microsoft Academic Search

One possible loosening mechanism of the femoral component in total hip replacement is fatigue cracking of the cement mantle. A computational method capable of simulating this process may therefore be a useful tool in the preclinical evaluation of prospective implants. In this study, we investigated the ability of a computational method to predict fatigue cracking in experimental models of the

Jonathan R. T. Jeffers; Martin Browne; Alexander B. Lennon; Patrick J. Prendergast; Mark Taylor



A telemetry system for the detection of hip prosthesis loosening by vibration analysis  

Microsoft Academic Search

This paper proposes a system for the detection of hip prosthesis loosening by means of a vibration analysis technique. Although this technique has been adapted before, the novelty presented here lies in the fact that the monitoring is done inside the prosthesis itself, offering better measurement results. Thus, an implantable monitoring system is required, involving low power consumption and miniaturization.

R Puers; M Catrysse; G Vandevoorde; R. J Collier; E Louridas; F Burny; M Donkerwolcke; F Moulart



Controversies in Large Metal-on-Metal Cementless Total Hip Arthroplasty  

Microsoft Academic Search

Over the last several years, many orthopaedic surgeons have embraced so-called alternative bearing surfaces in total hip arthroplasty, largely on the basis of the hypothesis that a reduction in the volumetric wear rates afforded by these improved articulating couples will reduce the prevalence of osteolysis and aseptic loosening, which in turn will improve implant survivorship. We conducted the study on

P. Botez; C. I. Stoica; P. D. Sirbu; R. Asaftei; C. Grierosu



Factors contributing to rapid wear and osteolysis in hips with modular acetabular bearings made of Hylamer  

Microsoft Academic Search

There have been several reports of osteolysis associated with rapid wear of Hylamer. A detailed analysis of retrieved implants and tissues can identify factors contributing to rapid wear and osteolysis. The mean linear wear rate of 12 liners was 0.49 mm\\/y, and 11 of 12 hips had progressive retroacetabular osteolysis. The average patient age was 50 years, and the mean

David L. Scott; Pat A. Campbell; Christian D. McClung; Thomas P. Schmalzried



Compliant positioning of total hip components for optimal range of motion  

Microsoft Academic Search

Impingement between femoral neck and endoprosthetic cup is one of the causes for dislocation in total hip arthroplasty (THA). Choosing a correct combined orientation of both components, the acetabular cup and femoral stem, in manual or computer-assisted implantation will yield a maximized, stable range of motion (ROM) and will reduce the risk for dislocation. A mathematical model of a THA

K.-H. Widmer; B. Zurfluh



Proximal femoral osteotomy as an adjunct in cementless revision total hip arthroplasty.  


Cementless total hip replacement techniques are increasingly used in revision arthroplasty. A major challenge is to achieve implant stability in a femur distorted by a failed arthroplasty. Five patients with aseptic loosening of cemented primary or revision total hip replacements complicated by significant proximal femoral disease, four with marked angular deformity of the femur and one with a subtrochanteric nonunion, were treated successfully with cementless revision arthroplasty combined with proximal femoral osteotomy. At follow-up examination, all femoral and trochanteric osteotomies had healed and D'Aubigne and Postel scores for pain, function, and range of motion had improved. All porous prostheses demonstrated radiographic features consistent with bone ingrowth fixation. No progressive stress shielding has been observed. Concomitant femoral osteotomy to correct anatomic deformity, in association with cementless total hip arthroplasty, results in union of the osteotomy and restoration of hip function. PMID:3572412

Glassman, A H; Engh, C A; Bobyn, J D



1-stage primary arthroplasty of mechanically failed internally fixated of hip fractures with deep wound infection  

PubMed Central

Background and purpose Mechanically failed internal fixation following hip fracture is often treated by salvage arthroplasty. If deep wound infection is present, a 2-stage procedure is often used. We have used a 1-stage procedure in infected cases, and we now report the outcome. Patients and methods We reviewed 16 cases of deep wound infection after mechanically failed hip fracture fixation, treated between 1994 and 2010. In all patients, a joint prosthesis was implanted in a 1-stage procedure. Results After an average follow-up period of 12 (2–18) years, no reinfection was detected. In 4 cases, a hip dislocation occurred and 3 of these needed further surgery. Interpretation A 1-stage procedure for arthroplasty of an infected, mechanically failed hip fracture fixation is feasible and carries a low risk of infection.

Klatte, Till O; O'Loughlin, Padraigh F; Citak, Mustafa; Rueger, Johannes M; Gehrke, Thorsten; Kendoff, Daniel



The effect of proximally and fully porous-coated canine hip stem design on bone modeling.  


Porous coated canine femoral hip replacement implants were evaluated for biological fixation by bone ingrowth and the effect of the extent of porous coating on bone modeling. The Co-Cr alloy implants were either fully porous coated or coated only on the proximal 40% of the stem. Two implants of each type were studied 9, 16, and 36 months after surgery. Implant fixation and bone modeling were assessed radiographically throughout the implant periods and histologically after the test animals were killed. All 12 implants appeared stably fixed within the femur and were bone-ingrown in the porous region. Radiographic features such as proximal medial and anterior cortical thinning, proximal cancellous bone hypertrophy, and new endosteal bone formation near the stem tip were noted within the first postoperative year, with no appreciable change thereafter. The extent of proximal cortical thinning varied from virtually none to as much as 40%, being more prominent with the proximally coated implants at 16 months and with the fully coated implants at 36 months. Of consistent note was cancellous hypertrophy at the junction of porous and smooth implant surfaces with proximally coated implants and new endosteal bone formation and ingrowth at the stem tip of fully coated implants. These results indicate that the proximally porous-coated implant design causes increased proximal stress transfer, but this does not necessarily preclude proximal cortical resorption. PMID:3305844

Bobyn, J D; Pilliar, R M; Binnington, A G; Szivek, J A



Conservation of sequence in recombination signal sequence spacers.  

PubMed Central

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

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



On optimal placement of spacers in bundled conductors  

NASA Astrophysics Data System (ADS)

The paper is devoted to the optimization of the placement of spacer-dampers in bundled conductors of overhead transmission lines. The main purpose of the spacers' use is to align individual conductors in a bundle and to assure the adequate spacing between them. At the same time, however, the spacers may provide damping which is desirable for minimizing the wind-induced vibrations. Such vibrations, via fatigue of conductors, lead to major damage and maintenance costs. Fatigue occurs mainly at the tension and suspension clamps, and also at the spacer clamps. At these points the forces applied to the conductor can, in a first approximation, be assumed as concentrated forces. In the present paper aeolian excitation due to the wind is modelled as a stationary time-and-space-dependent random field, whose spatial and temporal spectra account for yearly distributions of wind speed and turbulence. This assumption allows calculation of the mean square (MSQ) values of bending stresses at the above mentioned critical points. Fatigue accumulation theories for stationary processes provide a direct injective relation between the lifetime of a specimen and the MSQ value of loading; thus, to maximize the conductor's lifetime one should optimize the spacer-dampers as well as their placement, with regard to the maximum of the MSQ bending stresses along the span. We only deal with the optimization of the placement. The maximum of the MSQ of the bending stresses is the cost function. The vibration of conductors is modeled by the wave equation.

Kazimierczyk, P.; Hagedorn, P.


Mandrel and spacer engineering based self-aligned triple patterning  

NASA Astrophysics Data System (ADS)

Self-aligned triple patterning (SATP) technique offers both improved resolution and quasi-2D design flexibility for scaling integrated circuits down to sub-15nm half pitch. By implementation of active layout decomposition/synthesis using mandrel and spacer engineering, SATP process represents a prospective trend that not only drives up the feature density, but also breaks the 1-D gridded limitations posed to future device design. In this paper, we shall present the research progress made in optimizing SATP process to improve its lithographic performance. To solve the previously reported difficulties in etching small mandrels and removing sacrificial spacers, new materials are tested and a promising scheme (using oxide as the mandrel and poly/amorphous Si as the sacrificial spacer) is identified. In the new process, a diluted HF process is applied to shrink the mandrel (oxide) line CD and a highly selective dry etch (which does not attack the mandrel and structural spacer) is developed to strip the sacrificial Si spacers, resulting in significantly improved process performance. We also address the issue of reducing SATP process complexity by exploring the feasibility of a 2-mask concept for specific types of layout.

Chen, Yijian; Cheng, Qi; Kang, Weiling



Risk of cancer with metal-on-metal hip replacements: population based study  

PubMed Central

Objective To assess the risk of cancer associated with modern primary metal-on-metal hip replacements. Design Population based study. Setting Nationwide retrospective comparative register. Participants 10?728 patients who underwent metal-on-metal total hip arthroplasty and 18?235 patients who underwent conventional metal-on-polyethylene, ceramic-on-polyethylene, and ceramic-on-ceramic total hip arthroplasty (the non-metal-on-metal cohort) in the Finnish Arthroplasty Register 2001-10. Data on cancer cases up to 2010 for these cohorts were extracted from the Finnish Cancer Registry. Main outcome measures The relative risk of cancer was expressed as the ratio of observed to expected number of cases from the Finnish population—that is, the standardised incidence ratio. The relative risk of cancer in the metal-on-metal cohort compared with the non-metal-on-metal cohort was estimated with analyses of these ratios and Poisson regression. Results The overall risk of cancer in patients with metal-on-metal hip implants was similar to that in the Finnish population (378 observed v 400 expected, standardised incidence ratio 0.95, 95% confidence interval 0.85 to 1.04). The overall risk of cancer in patients with metal-on-metal hip implants was also no higher than in patients who had received non-metal-on-metal hip implants (relative risk 0.92, 0.81 to 1.05). Conclusions Metal-on-metal hip replacements are not associated with an increased overall risk of cancer during a mean follow-up of four years.



Total hip arthroplasty in patients younger than 21 years: a minimum 10-year follow-up  

PubMed Central

Introduction To evaluate the function, radiographic results and implant survival in patients younger than 21 years at the time of operation and with at least a 10-year follow-up, we reviewed the course of young adults who underwent total hip arthroplasty at McGill University Health Centre. Patients and methods Twelve patients (16 hips) met the criteria for inclusion in this study. They ranged in age from 10–20 years (median 16.5 yr). One patient (1 hip) died 5 years after the index surgery and was excluded from the study. Functional results were measured by the Harris hip score, and radiographs of surviving implants were assessed for radiolucencies, osteolysis and eccentric polyethylene wear. Results Eleven arthroplasties were cementless, 2 were hybrid and 2 were cemented. At follow-up ranging from 10 to 25 years (mean 13.6 yr), the Harris hip score ranged from 34.2–97.2 (mean 64.5). Four (26%) acetabular components were revised and (at the time of writing) 1 required revision. Only 1 (7%) femoral stem was revised. Radiographically, there was a high prevalence of eccentric polyethylene wear, but none of the surviving implants were found to be loose. Overall, 67% (10 of 15) of the total hip arthroplasties continued to function well at a mean of 13.6 years postoperatively. Conclusions Total hip arthroplasty remains a reasonable option in adolescence and early adulthood in selected patients with severe debility from multiple joint disease. Polyethylene wear is a particularly significant problem in this group of active young people.

Bessette, BenoIt J.; Fassier, Francois; Tanzer, Michael; Brooks, Caleb E.



Accelerating failure rate of the ASR total hip replacement.  


There is widespread concern regarding the incidence of adverse soft-tissue reactions after metal-on-metal (MoM) hip replacement. Recent National Joint Registry data have shown clear differences in the rates of failure of different designs of hip resurfacing. Our aim was to update the failure rates related to metal debris for the Articular Surface Replacement (ASR). A total of 505 of these were implanted. Kaplan-Meier analysis showed a failure rate of 25% at six years for the ASR resurfacing and of 48.8% for the ASR total hip replacement (THR). Of 257 patients with a minimum follow-up of two years, 67 (26.1%) had a serum cobalt concentration which was greater than 7 ?g/l. Co-ordinate measuring machine analysis of revised components showed that all patients suffering adverse tissue reactions in the resurfacing group had abnormal wear of the bearing surfaces. Six THR patients had relatively low rates of articular wear, but were found to have considerable damage at the trunion-taper interface. Our results suggest that wear at the modular junction is an important factor in the development of adverse tissue reactions after implantation of a large-diameter MoM THR. PMID:21768621

Langton, D J; Jameson, S S; Joyce, T J; Gandhi, J N; Sidaginamale, R; Mereddy, P; Lord, J; Nargol, A V F



Lubricin and smooth muscle ?-actin-containing myofibroblasts in the pseudomembranes around loose hip and knee prostheses.  


The objective was to evaluate the presence and distribution of the lubricating and anti-adhesion glycoprotein lubricin and cells containing the contractile isoform smooth muscle ?-actin (SMA) in pseudomembranes around loose hip prostheses. Periprosthetic tissue was obtained at revision arthroplasty of eight aseptic, loose hip implants, and for comparison three loose knee prostheses. Immunohistochemical analysis was performed in 3 zones: zone 1, within 300?m of the edge of the implant-tissue interface; zone 2, between zones 1 and 3; zone 3, within 300?m of the resected/trimmed edge. The presence of lubricin was extensive in all samples: (1) as a discrete layer at the implant-tissue interface; (2) within the extracellular matrix (ECM); (3) intracellularly. There was significantly more high grade (>50%) lubricin surface staining at the implant-tissue interface compared with the resected edge. While there was also a significant effect of location of high grade ECM lubricin staining, there was no significant effect of implant type (i.e. hip versus knee). All but two hip pseudomembrane samples showed the presence of many SMA-containing cells. There was a significant effect of location on the number of SMA-expressing cells, but not of implant type. These findings might explain why the management of loose prosthesis is so challenging. PMID:23174700

Cheriyan, Thomas; Ready, John E; Brick, Gregory W; Martin, Scott D; Martin, Tamara L; Schmid, Thomas M; Padera, Robert F; Spector, Myron



Hot isostatic pressing-processed hydroxyapatite-coated titanium implants: light microscopic and scanning electron microscopy investigations.  


Hot isostatic pressing (HIP) was used in a new procedure to produce hydroxyapatite (HA) coatings on a commercially pure titanium (cpTi) substrate for osseous implantation. Eighteen HIP-processed HA-coated implants were placed in the inferior border of the mandibles in 2 Labrador retriever dogs and left submerged for 3 months. As control specimens, 12 sandblasted cpTi implants were placed in the same mandibles and, to compare the bone reaction, 2 additional plasma-sprayed HA-coated implants (Integral) were placed. Tissue reactions at the bony interfaces of the implants were studied in ground sections with the implants in situ, using ordinary, fluorescent, and polarized light microscopy and scanning electron microscopy (SEM). The HIP-processed HA coatings displayed an increased density in light microscopy and SEM as compared to plasma-sprayed coatings. Direct bone-implant contact was found in all 3 types of surfaces. However, the production of new bone was far more abundant for the HA-coated implants than for sandblasted cpTi implants. The presence of bone-forming and bone-resorbing cells indicated active bone remodeling in the interface area at 3 months after implant placement. The present results support the view that epitaxial bone growth may occur from the HA-coated implant surface. It was concluded that the increased density of the present HIP-processed HA material does not reduce the bioactive properties of the coatings. PMID:9857595

Wie, H; Herø, H; Solheim, T


Bicentric bipolar hip prosthesis: A radiological study of movement at the interprosthetic joint  

PubMed Central

Background: The bipolar hip prostheses after some time functions as a unipolar device. There is a need to change the design of bipolar hip prostheses to make it function as a bipolar device over a prolonged period of time. A bicentric bipolar hip prosthesis was used as an implant for various conditions of the hip. We evaluated the movement of this newly developed prosthesis at the interprosthetic joint radiologically at periodic intervals. Materials and Methods: Fifty two cases were operarted with the Bicentric bipolar prosthesis for indications like fracture neck of femur and various other diseases of the hip and were followed up with serial radiographs at periodic intervals to evaluate, what fraction of the total abduction at the hip was occurring at the interprosthetic joint. Results: In cases of intracapsular fracture neck of femur, the percentage of total abduction occurring at the interprosthetic joint at 3 months follow-up was 33.74% (mean value of all the patients), which fell to 25.66% at 1.5 years. In indications for bipolar hemireplacement other than fracture neck of femur, the percentage of total abduction occurring at the interprosthetic joint at 3 months follow-up was 71.71% (mean value) and at 1.5 years it was 67.52%. Conclusion: This study shows the relative preservation of inner bearing movement in the bipolar hip prosthesis with time probably due its refined design. Further refinements are needed to make the prosthesis work better in patients of intracapsular fracture neck femur.

Rai, Anil Kumar; Singh, Saurabh; Kumaraswamy, Vinay; Khare, GN; Yadav, Vinit; Agarwal, Rakesh



Hip Abduction Can Prevent Posterior Edge Loading of Hip Replacements  

PubMed Central

Edge loading causes clinical problems for hard-on-hard hip replacements, and edge loading wear scars are present on the majority of retrieved components. We asked the question: are the lines of action of hip joint muscles such that edge loading can occur in a well-designed, well-positioned acetabular cup? A musculoskeletal model, based on cadaveric lower limb geometry, was used to calculate for each muscle, in every position within the complete range of motion, whether its contraction would safely pull the femoral head into the cup or contribute to edge loading. The results show that all the muscles that insert into the distal femur, patella, or tibia could cause edge loading of a well-positioned cup when the hip is in deep flexion. Patients frequently use distally inserting muscles for movements requiring deep hip flexion, such as sit-to-stand. Importantly, the results, which are supported by in vivo data and clinical findings, also show that risk of edge loading is dramatically reduced by combining deep hip flexion with hip abduction. Patients, including those with sub-optimally positioned cups, may be able to reduce the prevalence of edge loading by rising from chairs or stooping with the hip abducted. © 2013 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 31:1172–1179, 2013.

van Arkel, Richard J; Modenese, Luca; Phillips, Andrew TM; Jeffers, Jonathan RT



Racial differences in hip axis lengths might explain racial differences in rates of hip fracture  

Microsoft Academic Search

Compared with white women, Asian women have about a 40%–50% and blacks a 50%–60% lower risk of hip fracture, but the reason for this racial difference is not known. Women with a shorter hip axis have a lower risk of hip fracture. To test the hypothesis that a shorter hip axis length could account for the lower risk of hip

S. R. Cummings; J. A. Cauley; L. Palermo; P. D. Ross; R. D. Wasnich; D. Black; K. G. Faulkner



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



Hip fracture management and outcomes in Finland  

Microsoft Academic Search

Hip fracture is a common, devastating, and often fatal trauma in older people. In Finland, the incidence of hip fractures increased steadily until the late 1990's. Thereafter signs of declining incidence trend have been observed. Currently, the annual number of hip fractures is over 7000. The hip fracture patients are predominantly women (70%) aged 80years and over, and most (76%)

E. Lönnroos; I. Kiviranta; S. Hartikainen



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


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



Improving pre-operative planning for complex total hip replacement with a Rapid Prototype model enabling surgical simulation.  


Pre-operative planning for total hip replacement (THR) is challenging in hips with severe acetabular deformities, including those with a hypoplastic acetabulum or severe defects and in the presence of arthrodesis or ankylosis. We evaluated whether a Rapid Prototype (RP) model, which is a life-sized reproduction based on three-dimensional CT scans, can determine the feasibility of THR and provide information about the size and position of the acetabular component in severe acetabular deformities. THR was planned using an RP model in 21 complex hips in five men (five hips) and 16 women (16 hips) with a mean age of 47.7 years (24 to 70) at operation. An acetabular component was implanted successfully and THR completed in all hips. The acetabular component used was within 2 mm of the predicted size in 17 hips (80.9%). All of the acetabular components and femoral stems had radiological evidence of bone ingrowth and stability at the final follow-up, without any detectable wear or peri-prosthetic osteolysis. The RP model allowed a simulated procedure pre-operatively and was helpful in determining the feasibility of THR pre-operatively, and to decide on implant type, size and position in complex THRs. Cite this article: Bone Joint J 2013;95-B:1458-63. PMID:24151263

Won, S-H; Lee, Y-K; Ha, Y-C; Suh, Y-S; Koo, K-H



Prolonged incubation time does not increase sensitivity for the diagnosis of implant-related infection using samples prepared by sonication of the implants.  


We have designed a prospective study to evaluate the usefulness of prolonged incubation of cultures from sonicated orthopaedic implants. During the study period 124 implants from 113 patients were processed (22 osteosynthetic implants, 46 hip prostheses, 54 knee prostheses, and two shoulder prostheses). Of these, 70 patients had clinical infection; 32 had received antibiotics at least seven days before removal of the implant. A total of 54 patients had sonicated samples that produced positive cultures (including four patients without infection). All of them were positive in the first seven days of incubation. No differences were found regarding previous antibiotic treatment when analysing colony counts or days of incubation in the case of a positive result. In our experience, extending incubation of the samples to 14 days does not add more positive results for sonicated orthopaedic implants (hip and knee prosthesis and osteosynthesis implants) compared with a conventional seven-day incubation period. PMID:23814257

Esteban, J; Alvarez-Alvarez, B; Blanco, A; Fernández-Roblas, R; Gadea, I; Garcia-Cañete, J; Sandoval, E; Valdazo, M



Experience with the Metasul total hip bearing system.  


The author and Sulzer Medical Technology Ltd, Switzerland, have developed a new generation of metal on metal bearing total hip joints. The design is different than the McKee type prostheses in that the cobalt chrome alloy heads and cups (Metasul) are of the highest precision with controlled loose fitting. These allow low friction and low wear of approximately 5 micrometers per year. It is anticipated that debris related late loosening will be avoided by the use of this design. Approximately 30,000 Metasul hearings have been produced. The first 110 Weber metal on metal hip implants have been analyzed. No adverse effects from the wear of the new metal on metal components have been noted in this series. PMID:8769324

Weber, B G



Salvage hip arthroplasty after failed fixation of proximal femur fractures.  


We reviewed 46 patients who underwent salvage hip arthroplasty (SHA) for revision of failed cannulated screws (CS), sliding hip screws (SHS), or intramedullary nails (IMN). The primary objective was to determine differences in operative difficulty. SHA after failed femoral neck fixation was associated with lower intra-operative demands than after failed peri-trochanteric fractures. Similarly, analysis by the index implant found that conversion arthroplasty after failed CSs was associated with lower intra-operative morbidity than failed SHSs or IMNs; differences between SHS and IMN were not as clear. Importantly, intra-operative data in cases of failed SHSs were similar regardless of the original fracture type, showing the device played a larger role than the fracture pattern. Complications and revision surgery rates were similar regardless of fracture type or fixation device. Our results suggest that operative demands and subsequent patient morbidity are more dependent on the index device than the fracture pattern during SHA. PMID:23489728

DeHaan, Alexander M; Groat, Tahnee; Priddy, Michael; Ellis, Thomas J; Duwelius, Paul J; Friess, Darin M; Mirza, Amer J



Modular hybrid total hip arthroplasty. Experimental study in dogs  

PubMed Central

Background This prospective experimental study evaluated the surgical procedure and results of modular hybrid total hip arthroplasty in dogs. Methods Ten skeletally mature healthy mongrel dogs with weights varying between 19 and 27 kg were used. Cemented modular femoral stems and uncemented porous-coated acetabular cups were employed. Clinical and radiographic evaluations were performed before surgery and at 30, 60, 90, 120, 180 and 360 days post-operation. Results Excellent weight bearing was noticed in the operated limb in seven dogs. Dislocation followed by loosening of the prosthesis was noticed in two dogs, which were therefore properly treated with a femoral head osteotomy. Femoral fracture occurred in one dog, which was promptly treated with full implant removal and femoral osteosynthesis. Conclusions The canine modular hybrid total hip arthroplasty provided excellent functionality of the operated limb.



Peri-Implant Diseases  


... Gum Disease Regenerative Procedures Dental Crown Lengthening Procedure Dental Implants Single Tooth Implants Multiple Tooth Implants Full Mouth Dental Implants Sinus Augmentation Ridge Modification Periodontal Pocket Reduction Procedures ...


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.

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



The important challenge to extend spacer DP process towards 22nm and beyond  

NASA Astrophysics Data System (ADS)

Double patterning processes are techniques that can be used to form etching mask patterns for 32nm node and possibly for 22nm node as well. The self-aligned spacer process has drawn much attention as an effective means of enabling the formation of repetitive patterns. The self-aligned spacer process is now being used in actual device manufacturing, but it has many process steps driving up process cost while also assuming a 1D pattern. This paper demonstrates extensions of the self-aligned spacer process by an enhanced 2D positive spacer process and a newly developed spacer DP process using a 1D negative spacer.

Oyama, Kenichi; Nishimura, Eiichi; Kushibiki, Masato; Hasebe, Kazuhide; Nakajima, Shigeru; Murakami, Hiroki; Hara, Arisa; Yamauchi, Shohei; Natori, Sakurako; Yabe, Kazuo; Yamaji, Tomohito; Nakatsuji, Ryota; Yaegashi, Hidetami



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



Traumatic injuries of the hip.  


Traumatic lesions of the hip in athletes may be clinically challenging because of the overlap in clinical presentation due to differing pathologies and the presence of multiple injuries. Imaging of the hip in the athlete has undergone a recent resurgence of interest and understanding related to the increasing accessibility and use of hip arthroscopy, which expands the treatment options available for intra-articular pathology. MR imaging and MR arthrography have a unique role in diagnosis of these pathologies, guiding the surgeon, arthroscopist, and referring clinician in their management of bony and soft tissue injury. PMID:19887297

Marshall, Nina; Koulouris, George



Ambulatory activities maintain cortical bone after total hip arthroplasty.  


Because periprosthetic bone loss impacts revision total hip arthroplasties and subsequent patient recovery, it is important to understand the consequences of stress shielding. We characterized bone loss attributed to stress shielding by investigating the influence of patient activity and demographics on reductions in cortical bone cross-sectional area, bone mineral density, and bone mineral content. Cortical bone shape, bone mineral content, and bone mineral density were measured in implanted and contralateral nonimplanted cadaveric femurs. Geometric measurements of transverse cross sections were measured with imaging software. Dual energy x-ray absorptiometry measured bone mineral content and bone mineral density. Patient activity was estimated by the mechanical usage score. The mechanical usage score was comprised of the ambulatory components of the Harris hip score. Regression analysis revealed a lower mechanical usage score and patient weight correlated with greater bone loss. Age, implant size, and time in situ did not correlate to bone loss. The implanted femurs were reduced in cross-sectional area and rigidity, and expanded endosteally and periosteally. Principal axis location did not change. Bone loss was more likely to occur uniformly than to change cortical bone distribution. Bone loss was minimized in patients with higher activity levels. PMID:16721349

Rosenbaum, Teri G; Bloebaum, Roy D; Ashrafi, Shadi; Lester, D Kevin



Monte Carlo characterization of materials for prosthetic implants and dosimetric validation of Pinnacle 3 TPS  

Microsoft Academic Search

In external beam radiotherapy the calculation of dose distribution for patients with hip prostheses is critical. Metallic implants not only degrade the image quality but also perturb the dose distribution. Conventional treatment planning systems do not accurately account for high-Z prosthetic implants heterogeneities, especially at interfaces. The materials studied in this work have been chosen on the basis of a

Francesca Palleri; Fabio Baruffaldi; Anna Lisa Angelini; Andrea Ferri; Emiliano Spezi



CAD-CAM-RTV – lost-wax casting technology for medical implants  

Microsoft Academic Search

Purpose – The purpose of this paper is to present the development of a technical procedure for the manufacturing of medical implant prototypes. Design\\/methodology\\/approach – The paper was performed on a new hip implant design and manufactured with different metallic alloys F75 (ASTM) commonly used in biomedical applications. Dimensional parameters between the computer-aided design (CAD) geometry and the prototypes and

António Manuel de A. Monteiro Ramos; José António Simões



Implant vendors and hospitals: Competing influences over product choice by orthopedic surgeons  

Microsoft Academic Search

Background: Vendors of hip and knee implants court orthopedic surgeons to adopt their products. Hospitals, which have to pay for these products, now court the same surgeons to help reduce the number of vendors and contain implant costs. Purposes: This study measures the surgeon's perceived alignment of interests with both vendors and hospitals and gauges surgeons' exposure and receptivity to

Lawton R. Burns; Michael G. Housman; Robert E. Booth; Jr Aaron Koenig



[Are the concerns regarding metal-on-metal total hip arthroplasties founded in 2012?].  


Metal-on-metal total hip arthroplasty (MOM THA) fuels debate in the orthopedic community after statistics showed higher-than-expected short-term failures in comparison with metal-on-polyethylene THA. The problem of early failure in the young, active patient with a metal-on-polyethylene implant has prompted the research of another couple. Multiple studies showed the advantages of MOM THA. The results of MOM resurfacing and MOM THA in our hospital did not show concerning results. Nonetheless, the data in the literature shows divergent opinions. The most recent statistics indicate that the results are disappointing, particularly with specific types of implants. Several institutions, in the USA and in Europe, are developing protocols for the follow-up of patients with MOM hip implants. Today, we are headed towards imposing a moratorium on using MOM THA. PMID:23444826

Valcu, C A; Perdreau, A; Wouters, A; Gillet, Ph



Modular cementless cup for total hip arthroplasty: results at 4-year follow-up.  


The aim is to perform the assessment of a modular cementless acetabular cup with a tapered internal design for all bearing couplings. In 190 unselected consecutive patients, 207 total hip arthroplasties were implanted. The implants were clinically and radiographically evaluated. Follow-up was 49.7 ± 8.1 months. The average Harris hip score improved from 55.5 ± 5.7 to 94.7 ± 3.4 (P < 0.05). All cups were well-positioned and stable. The Kaplan-Maier cumulative survivorship was 98.5 ± 0.8%. No significant differences have been noted in dividing patients according to the different liner materials (P < 0.005). The study, whose rationale is the novelty of this kind of implant, suggests the efficacy of the Delta-PF acetabular cup. PMID:22223107

Bistolfi, Alessandro; Massazza, Giuseppe; Rosso, Federica; Ventura, Stefano; Lagalla, Francesco; Crova, Maurizio



[Ceramic head fracture--a rare complication in hip endoprosthesis. Case report and literature survey].  


Since introduction of the prosthetic joint replacement numerous design modifications have taken place. Some were successful other were given up after short time. During almost twenty years now in joint arthroplasty of the hip components made of A12 03-ceramics--ball and/or socket--are used. Many papers have reported about the results of these implants. One of the possible complications described in the literature is the breakage of the ceramic component(s). Since April 1981 we have implanted over 500 cementless prosthesis of the hip in combination with a ceramic ball. In one patients we observed a breakage of the head two years after implantation. We will describe the story of this case and discuss possible reasons for this complication in reference to the literature. PMID:2147348

Kern, S; Schreiber, A; Hilfiker, B


Total hip arthroplasty for active tuberculosis of the hip  

Microsoft Academic Search

Total hip arthroplasty (THA) has been used as a successful form of treatment in patients with long-standing tuberculosis,\\u000a but it is unclear whether THA should be performed in patients with current infection. We performed THA in six patients with\\u000a advanced active tuberculosis of the hip from 2002 to 2006. Tuberculosis was confirmed in all cases by histological examination.\\u000a All patients

Yongqing Wang; Jingsheng Wang; Zhanmin Xu; Yuan Li; Huimin Wang



Implantable Microimagers  

PubMed Central

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

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



Comparison of techniques for correction of magnification of pelvic X-rays for hip surgery planning.  


The aim of this study was to develop an accurate method for correction of magnification of pelvic x-rays to enhance accuracy of hip surgery planning. All investigated methods aim at estimating the anteroposterior location of the hip joint in supine position to correctly position a reference object for correction of magnification. An existing method-which is currently being used in clinical practice in our clinics-is based on estimating the position of the hip joint by palpation of the greater trochanter. It is only moderately accurate and difficult to execute reliably in clinical practice. To develop a new method, 99 patients who already had a hip implant in situ were included; this enabled determining the true location of the hip joint deducted from the magnification of the prosthesis. Physical examination was used to obtain predictor variables possibly associated with the height of the hip joint. This included a simple dynamic hip joint examination to estimate the position of the center of rotation. Prediction equations were then constructed using regression analysis. The performance of these prediction equations was compared with the performance of the existing protocol. The mean absolute error in predicting the height of the hip joint center using the old method was 20 mm (range -79 mm to +46 mm). This was 11 mm for the new method (-32 mm to +39 mm). The prediction equation is: height (mm) = 34 + 1/2 abdominal circumference (cm). The newly developed prediction equation is a superior method for predicting the height of the hip joint center for correction of magnification of pelvic x-rays. We recommend its implementation in the departments of radiology and orthopedic surgery. PMID:17192815

The, Bertram; Kootstra, Johan W J; Hosman, Anton H; Verdonschot, Nico; Gerritsma, Carina L E; Diercks, Ron L



High Productivity Implantation ``PARTIAL IMPLANT''  

NASA Astrophysics Data System (ADS)

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

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



Replacement of the Trapezium with a Silicone Rubber Ball Spacer  

Microsoft Academic Search

Twenty-two patients underwent twenty-five trapezium replacements with a silicone rubber ball spacer. Seventeen of these procedures (68%) produced excellent results, and a further six patients (24%) had satisfactory results after a follow up averaging 13.6 months. The complications of the procedure are described.




Fluid spacer composition for use in well cementing  

Microsoft Academic Search

A method is described of emplacing an aqueous cement slurry into a well bore which contains an oil base composition having dispersed therein oil wet particles. The method consists of: introducing into the well bore and into contact with the oil based composition, a spacer composition comprising: an aqueous fluid; a nonylphenol admixture comprising from about 20 to about 80

W. A. Weigand; P. L. Totten



Ion conductive spacers for increased power generation in reverse electrodialysis  

Microsoft Academic Search

Reverse electrodialysis (RED) is a sustainable energy source that converts the free energy of mixing of two solutions with different salinity directly into electrical energy. High power outputs are predicted theoretically, but the practical power output and the efficiency of the process are still relatively low. Next to concentration polarization phenomena, especially the spacer shadow effect, which occurs due to

Piotr D?ugo??cki; Joanna D?browska; Kitty Nijmeijer; Matthias Wessling



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


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



Abstract: Lightweight Authentication for HIP  

NASA Astrophysics Data System (ADS)

In recent years numerous solutions for overcoming the architectural constraints of the Internet have emerged. One of the most promising among them is the Host Identity Protocol (HIP) [2], which was recently approved as an experimental standard by the IETF. HIP adds an additional protocol layer between TCP and IP to implement the Identifier/Locator split. Apart from mobility and multihoming, HIP supports host authentication, payload encryption, and a cryptographic namespace without requiring changes to the network infrastructure or network applications. However, especially mobile devices with tightly limited CPU resources are slowed down by HIP. Its poor performance on these mobile devices is a result of the extensive use of public-key (PK) cryptography for securing the main protocol functions.

Heer, Tobias


Hip Fractures among Older Adults  


... and is frequently followed by admission to a nursing home and extensive rehabilitation. 2 One in three adults who lived independently before their hip fracture remains in a nursing home for at least a year after their ...


Total Hip Replacement Exercise Guide  


... exercises to restore your normal hip motion and strength and a gradual return to everyday activities are ... several times you stand. As you regain your strength, you will be able to stand independently. While ...


Ligand-receptor binding in the presence of polymeric spacers  

NASA Astrophysics Data System (ADS)

Ligand-receptor binding is of fundamental importance in many biological processes. Examples include cell-cell adhesion and cell-surface interactions among others. In several biomimetic materials as well as in some biological systems the ligand is attached to the surface by a spacer. In this talk we address the role that spacers play in ligand-receptor binding. More specifically, we present a series of theoretical studies in which we systematic study the role of polymeric spacers on the efficiency of ligand-receptor binding. The systems of interest correspond to the ligand chemically bound at the free end of polymers tethered to the surface, while the receptor is part of proteins free to move in the solution. Our theoretical approach is based on a molecular theory that has been shown to predict thermodynamic and structural information for tethered polymer layers in excellent agreement with experimental observations. We have generalized the theory to include the equilibrium between the bound and unbound species. We find that the presence of spacers increases the amount of binding as compared to the case in which the ligands are directly on the surface. The maximal binding is obtained at a relatively low surface coverage of spacer and it increases as the spacer chain length increases. The maximal binding is found to correspond to the cases in which the bound proteins can accommodate at different distances from the surface while bound to the ligand. We will show how the binding depends upon the size of the protein, the free energy of binding of the bare ligand-receptor pair, the polymer surface coverage and molecular weight. The predictions of the theory will be compared with recent experimental observations on the interactions between protein coated surfaces and surfaces with ligands at the end of polyethylene oxide spacers. Finally, we will show the use of mixed tethered layers to optimize ligand- receptor binding and at the same time to minimize non-specific adsorption of proteins. Throughout the presentation the interplay between different interactions in determining the binding will be discussed.

Szleifer, Igal



Preliminary Analysis and Design Optimization of the Short Spacer Truss of Space Station Freedom.  

National Technical Information Service (NTIS)

The analysis, dynamic simulation, and design optimization of the short spacer truss of the Space Station Freedom are presented in this report. The short spacer truss will be positioned between the integrated equipment assembly (IEA) and another truss, cal...

A. S. Gendy S. N. Patnaik D. A. Hopkins L. Berke



Performance Analysis and Test on the KAERI Devised Spacer Grids for PWRs  

NASA Astrophysics Data System (ADS)

Spacer grid which is one of the most important structural components in a pressurized light water reactor fuel assembly supports the fuel rods laterally and vertically. Based on design experiences and by scrutinizing the design features of advanced nuclear fuels and the international patents of spacer grids, KAERI has devised its own spacer grid shapes and acquired patents. In this study, a performance evaluation on two new spacer grid shapes devised by KAERI was carried out from mechanical/structural and thermohydraulic view points. And also a performance evaluation on two commercial spacer grid shapes was carried out for the sake of a comparison. The comparisons included the spring characteristics, fuel rod vibration characteristics, fretting wear resistance, impact strength characteristics, CHF enhancement, and pressure drop level of the spacer grid shapes. The comparison results have shown that the performances of the new spacer grid shapes are better or at least not worse than those of the commercial spacer grid shapes.

Song, Kee-Nam; Lee, Soo-Bum


Cementless total hip arthroplasty in Paget's disease of bone: a retrospective review  

PubMed Central

Paget’s disease of bone (PDB) is a localised chronic osteopathy leading to bone deformities, bone hypervascularity, structural weakness and altered joint biomechanics. The pelvis and upper femur are frequently involved, resulting in disabling hip disease, and total hip arthroplasty (THA) may be required. We performed a retrospective study on the management and the outcome of 39 uncemented hydroxyapatite fully-coated THA in patients with PDB of the hip. The follow-up averaged 79.4 months (range 24–194). Functional scores improved significantly and, using the Harris hip score, 84% of patients had an excellent clinical outcome at the latest follow-up. Despite one case of an uncemented acetabular component with probable loosening, no implant revision had been required at our latest follow-up. Signs of implant loosening were found to be significantly more frequent in patients with active disease. For this reason, we advocate the use of pre-operative medication with bisphosphonates to reduce disease activity. Another benefit of this treatment is the significant decrease of intra-operative blood loss. Provided the control of disease activity in the pre-operative period with bisphosphonates is achieved, good outcome of cementless THAs can be expected. Bisphosphonates reduced the risk of implant loosening and excessive intra-operative blood loss.

Pibarot, Vincent; Chapurlat, Roland; Carret, Jean-Paul; Bejui-Hugues, Jacques; Guyen, Olivier



Abduction pillow immobilization following hip surgery: a welcome alternative for selected patients  

PubMed Central

Background Studies have shown that when using a spica cast following hip surgery in children , there are associated complications such as soiling, pressure sores, and osteopenic fractures. Methods Charts were retrospectively reviewed for all patients who had undergone hip surgeries by one surgeon at one institution between 1999 and 2005. The method of post-operative immobilization (spica cast or abduction pillow) and complications were recorded for each patient. Results There was a total of 32 patients. Of these, 11—all of whom had a diagnosis of developmental dysplasia of the hip—were treated using a spica cast. In the 21 patients treated in an abduction pillow, 4 (19%) were switched to a spica cast for the following reasons: (1) distal femoral fracture as a result of vigorous resuscitation during a choking episode, (2) parental preference, (3) for added immobilization over concern of implant loss of fixation, and (4) concern of migration of the hip, which again migrated after being changed to a spica cast and eventually required a pelvic osteotomy. Conclusion It is our opinion that only one of these complications in the children treated with an abduction pillow (the case of possible implant migration) may have been avoided if the child had originally been placed in a spica cast. The child who was successfully resuscitated after a choking incident weeks after the surgery may have had a worse outcome if it had been in a spica cast. This incident occurred at home and the abduction pillow was easily and quickly removed to allow resuscitation. An abduction pillow is a welcome alternative to a spica cast following hip surgery for many patients with neuromuscular and syndromic conditions. However, in children with osteopenic bone at risk for implant failure and in children with unstable hip reductions, a spica cast may be preferable.

Albrektson, Josh; Kay, Robert M.; Tolo, Vernon T.



Successful treatment of total hip and knee infection with articulating antibiotic components: a modified treatment method.  


There are many problems associated with the use of articulating antibiotic cement spacer blocks and articulating components in the two-stage treatment of total hip replacement and total knee replacement infections. These include loss of motion during and after treatment, bone loss, generation of cement debris, inadequate dosing of cement with the appropriate antibiotic, and biologic failure. Forty-four patients with 54 consecutive periprosthetic hip and knee infections (31 septic total knee arthroplasties and 23 septic total hip arthroplasties) had treatment with a modified two-stage reimplantation protocol using articulating components made of antibiotic-cement-only prosthetic components and antibiotic-cement-covered prosthetic components between January 1995 and May 2002. Second-stage revision, after six weeks of parenteral antibiotics, was completed an average of 84 days after the first stage. A minimum two-year followup after final treatment is evaluated. One of the 23 total hip replacement infections persisted or recurred with the original organism(s) after treatment (95.7% success) as did two of the 31 total knee replacement infections (93.5% success). Combined success rate was 94.4%. This modified treatment method incorporates early range of motion during first-stage treatment with articulating components that provide local high-dose elution of broad-spectrum antibiotics, provides the flexibility of customizing the antibiotic cement components with culture-directed antibiotics, and results in a high biologic success rate. PMID:15552134

Evans, Richard P



A concept for hip prosthesis identification using ultra wideband radar.  


Ultra wideband (UWB) radar has been extensively investigated both theoretically and practically for the identification buried artifacts. Ground probe radar (GPR) concentrates on the identification of lightly buried land mines, unexploded ordnance (UXO) and archeological targets. The same technology is proposed in a similar context for the rapid identification of in vivo implanted metallic prostheses. The technique is based on resonance based target identification and the paper investigates UWB scattering from a metallic hip prosthesis in free space as a first step in the identification process. PMID:17271965

Lui, Hoi-Shun; Shuley, Nicholas; Crozier, Stuart



Controlling photoinduced electron transfer rates in donor-spacer-acceptor molecules by changing the electronic properties of the spacer  

NASA Astrophysics Data System (ADS)

Electron transfer in photosynthetic reaction centers was examined. Specifically, the nature of the medium that lies between the electron donors and acceptors in the reaction centers was studied. The approach was to synthesize four fixed-distance porphyrin-quinone molecules in order to study the effects of changing the orbital energies of the donor, acceptor, and intervening spacer molecules.

Wasielewski, Michael R.; Niemczyk, Mark P.; Johnson, Douglas G.


Hip resurfacing arthroplasty: short-term survivorship of 4,401 hips from the Finnish Arthroplasty Register  

PubMed Central

Background and purpose Population-based registry data from the Nordic Arthroplasty Register Association (NARA) and from the National Joint Register of England and Wales have revealed that the outcome after hip resurfacing arthroplasty (HRA) is inferior to that of conventional total hip arthroplasty (THA). We analyzed the short-term survival of 4,401 HRAs in the Finnish Arthroplasty Register. Methods We compared the revision risk of the 4,401 HRAs from the Register to that of 48,409 THAs performed during the same time period. The median follow-up time was 3.5 (0–9) years for HRAs and 3.9 (0–9) years for THAs. Results There was no statistically significant difference in revision risk between HRAs and THAs (RR = 0.93, 95% CI: 0.78–1.10). Female patients had about double the revision risk of male patients (RR = 2.0, CI: 1.4–2.7). Hospitals that had performed 100 or more HRA procedures had a lower revision risk than those with less than 100 HRAs (RR = 0.6, CI: 0.4–0.9). Articular Surface Replacement (ASR, DePuy) had inferior outcome with higher revision risk than the Birmingham Hip Resurfacing implant (BHR, Smith & Nephew), the reference implant (RR = 1.8, CI: 1.2–2.7). Interpretation We found that HRA had comparable short-term survivorship to THA at a nationwide level. Implant design had an influence on revision rates. ASR had higher revision risk. Low hospital procedure volume worsened the outcome of HRA. Female patients had twice the revision risk of male patients.



Midline-Splitting Open Door Laminoplasty Using Hydroxyapatite Spacers : Comparison between Two Different Shaped Spacers  

PubMed Central

Objective Although hydroxyapatite (HA) spacer has been used for laminoplasty, there have been no reports on factors associated with fusion and on the effects of HA shape. Methods During January 2004 and January 2010, 45 patients with compressive cervical myelopathy underwent midline-splitting open door laminoplasty with winged (33 cases) and wingless (12 cases) HAs by a single surgeon. Minimal and mean follow up times were 12 and 28.1 months, respectively. Japanese Orthopedic Association (JOA) score was used for clinical outcome measurement. Cervical X-rays were taken preoperatively, immediately post-operatively, and after 3, 6, and 12 months and computed tomography scans were performed preoperatively, immediately post-operatively and after 12 months. Cervical lordosis, canal dimension, fusion between lamina and HA, and affecting factors of fusion were analyzed. Results All surgeries were performed on 142 levels, 99 in the winged and 43 in the wingless HA groups. JOA scores of the winged group changed from 10.4±2.94 to 13.3±2.35 and scores of the wingless group changed from 10.8±2.87 to 13.8±3.05. There was no significant difference on lordotic and canal dimensional change between two groups. Post-operative 12 month fusion rate between lamina and HA was significantly lower in the winged group (18.2 vs. 48.8% p=0.001). Multivariate analysis showed that ossification of the posterior longitudinal ligament, male gender, and wingless type HA were significantly associated with fusion. Conclusion Clinical outcome was similar in patients receiving winged and wingless HA, but the wingless type was associated with a higher rate of fusion between HA and lamina at 12 months post-operatively.

Park, Jin Hoon



Effect of spacer layers on current-voltage characteristics of resonant-tunneling diode  

SciTech Connect

Using the numerical solution to the Schroedinger equation, current-voltage characteristics of the resonant-tunneling diode with spacer layers were obtained. The dependences of the peak current of the resonant-tunneling diode on the emitter spacer width were plotted. It was shown that the peak current depends periodically on the emitter spacer width. The constructed electron density diagrams showed that the increase in the peak current is associated with the resonant level in the emitter spacer region.

Remnev, M. A., E-mail:; Kateev, I. Yu.; Elesin, V. F. [MEPhI National Research Nuclear University (Russian Federation)



Hip Hip Hurrah! Hip size inversely related to heart disease and total mortality.  


During the past decade a series of published reports have examined the value of studying the relation between hip circumferences and cardiovascular end points. Specifically, in a series of recent studies the independent effects of hip circumference have been studied after adjustment for general obesity and/or waist circumference. These studies have been remarkable in terms of their consistency, and in the unexpected finding of an adverse effect of small hip size, after statistically correcting for differences in general and abdominal size. The hazard related to a small hip size may be stronger for women than men, but is evident in both genders. In this 'viewpoint', we wish to draw attention to the emerging body of evidence and to encourage researchers to continue collecting measures of lower body size in their surveys. PMID:20663064

Heitmann, B L; Lissner, L



Cochlear Implants  


... studying large groups of children who were identified early with hearing loss and implanted with a cochlear implant. Knowledge from this research will shed light on the variables most related to improved speech and language acquisition as well as reading and higher academic performance ...


Hydroxyapatite porous coating and the osteointegration of the total hip replacement  

Microsoft Academic Search

Introduction  The main purpose of this study is to evaluate the efficacy of the plasma sprayed, combined porous titanium alloy\\/HA coating\\u000a in promoting bony ingrowth and mechanical stabilization of total hip implants. The performance of the titanium alloy\\/HA type\\u000a coated hip prostheses and the one of the same shape but without any coating, is compared in this paper.\\u000a \\u000a \\u000a \\u000a Material and methods  The

Ivan Landor; Pavel Vavrik; Antonin Sosna; David Jahoda; Henry Hahn; M. Daniel



Femoral bone loss in revision total hip arthroplasty: evaluation and management.  


Primary total hip arthroplasty (THA) is one of the most effective procedures for managing end-stage hip arthritis. The burden of revision THA procedures is expected to increase along with the rise in number of primary THAs. The major indications for revision THA include instability, aseptic loosening, infection, osteolysis, wear-related complications, periprosthetic fracture, component malposition, and catastrophic implant fracture. Each of these conditions may be associated with mild or advanced bone loss. Careful patient evaluation and bone loss classification guide preoperative planning and overall patient care. Historically, uncemented fixation has provided the best results, but cemented fixation is required in some cases. PMID:24084434

Sheth, Neil P; Nelson, Charles L; Paprosky, Wayne G



Initial results with a mini-posterior approach for total hip arthroplasty  

PubMed Central

Implantation of the total hip prosthesis should always be as atraumatic as possible. The principle underlying this technique is to visualise the working area while keeping the aperture to a minimum, with a resulting reduction in trauma to the soft tissue. We present a new, improved single-incision approach in total hip arthroplasty: the mini-posterior approach. Preliminary results from 60 patients operated using this approach indicate rapid functional recovery, minimal postoperative pain, a reduced duration of hospitalisation, few complications, and optimal component positioning. Further follow-up is warranted.



Structural Allograft as an Option for Treating Infected Hip Arthroplasty with Massive Bone Loss  

Microsoft Academic Search

Background  Revision of the infected hip arthroplasty with major bone loss is difficult. Attempts to restore bone stock with structural\\u000a allograft are controversial.\\u000a \\u000a \\u000a \\u000a \\u000a Questions\\/purposes  We assessed the (1) reinfection rate; (2) rerevision rate; (3) radiographic graft union, resorption, and implant migration;\\u000a (4) Harris hip scores at 1 year and at last followup compared with before surgery; and (5) other major complications associated\\u000a with

Paul T. H. Lee; Robert A. Clayton; Oleg A. Safir; David J. Backstein; Allan E. Gross



Thermal behavior and thermal decomposition study of porphyrin polymers containing different spacer groups  

Microsoft Academic Search

A series of porphyrin polymers containing different spacer groups was synthesized and studied using TG, DSC and FTIR. The thermal behaviors including the possible conformation transition and phase transition of porphyrins were studied during the heating process at lower temperature. Polymers with spacer groups exhibit higher thermal stability compared to that without spacer group. Activation energies obtained by the iterative

Chunxiu Guan; liqing Li; Donghua Chen; Zongyong Gao; Wenbo Sun



In-situ electrochemical study of interaction of tribology and corrosion in artificial hip prosthesis simulators.  


The second generation Metal-on-Metal (MoM) hip replacements have been considered as an alternative to commonly used Polyethylene-on-Metal (PoM) joint prostheses due to polyethylene wear debris induced osteolysis. However, the role of corrosion and the biofilm formed under tribological contact are still not fully understood. Enhanced metal ion concentrations have been reported widely from hair, blood and urine samples of patients who received metal hip replacements and in isolated cases when abnormally high levels have caused adverse local tissue reactions. An understanding of the origin of metal ions is really important in order to design alloys for reduced ion release. Reciprocating pin-on-plate wear tester is a standard instrument to assess the interaction of corrosion and wear. However, more realistic hip simulator can provide a better understanding of tribocorrosion process for hip implants. It is very important to instrument the conventional hip simulator to enable electrochemical measurements. In this study, simple reciprocating pin-on-plate wear tests and hip simulator tests were compared. It was found that metal ions originated from two sources: (a) a depassivation of the contacting surfaces due to tribology (rubbing) and (b) corrosion of nano-sized wear particles generated from the contacting surfaces. PMID:23182693

Yan, Yu; Dowson, Duncan; Neville, Anne



Surface treatment on an implant cobalt alloy for high biocompatibility and wear resistance  

Microsoft Academic Search

Total hip prostheses are implanted to younger and more active patients, so the open problem is to create implants which will enhance the implant survivorship and will offer greater longevity. From this point of view, metal-on-metal arthroprostheses are well performing. The volume of periprosthetic inflammatory tissues appears to be less than with metal-on-UHMPWE, however osteolysis often occurs and it is

S. Spriano; E. Vernè; M. G. Faga; S. Bugliosi; G. Maina



Pathomorphologic Alterations Predict Presence or Absence of Hip Osteoarthrosis  

Microsoft Academic Search

Abnormal morphology of the hip has been associated with primary osteoarthrosis. We evaluated the morphology of 464 consecutive hips contralateral to hips treated by THA. We excluded all hips with known diagnoses leading to secondary osteoarthritis and all hips with advanced arthrosis to elimi- nate the effect of arthritic remodeling on the morphologic measurements. Of the remaining 119 hips, 25

Timo M. Ecker; Moritz Tannast; Marc Puls; Klaus A. Siebenrock; Stephen B. Murphy


Emerging topics on the hip: ligamentum teres and hip microinstability.  


Microinstability and ligament teres lesions are emergent topics on the hip pathology. These entities are an increasingly recognized cause of persistent hip pain and should be considered in the differential diagnosis of the patient with hip pain. Conventional (non-arthrographic) CT and MR have a very limited role in the evaluation of these entities. CTa and MRa have emerged as the modalities of choice for pre-operative imaging of ligamentum teres injuries and microinstability. To date, pre-operative imaging detection of these pathologies is not widespread but with appropriate imaging and a high index of suspicion, preoperative detection should improve. This article discusses current concepts regarding anatomy, biomechanics, clinical findings, diagnosis and treatment of ligament teres lesions and microinstability. PMID:21723682

Cerezal, Luis; Arnaiz, Javier; Canga, Ana; Piedra, Tatiana; Altónaga, José R; Munafo, Ricardo; Pérez-Carro, Luis



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


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


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


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 PMID:23737445

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



Method of using a spacer for well control fluid  

SciTech Connect

A spacer comprising the water-in-oil emulsion portion of a shear-thickening well control fluid is used to separate drilling mud from the shear-thickening fluid in the drill pipe in the well bore to avoid premature thickening of the shear thickening fluid in the drill pipe. The shear-thickening well control fluid comprises a water-in-oil emulsion in which is dispersed granular particles of hydratable, water expandable clay.

Drake, E.N.; Tsao, Y.H.



Propping-agent spacer effective in gas-well fracturing  

Microsoft Academic Search

Oil-soluble propping-agent spacers have shown good results in 15 Basin Dakota Field gas wells in the Four Corners area of New Mexico. Initial potentials of the wells fractured with the spaced props averaged 5358 Mcfd--19% more than the average of 4487 Mcfd in offset wells fractured with unspaced props. A table shows how these 15 gas condensate wells responded to

C. R. Fast; F. L. Nabors; G. D. Mase



Biomechanics of lateral interbody spacers: going wider for going stiffer.  


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



Structural design feasibility study of Space Station long spacer truss  

NASA Astrophysics Data System (ADS)

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.



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.

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



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


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



Appendix A: Hip Implant Device Utilization in the U  

Center for Biologics Evaluation and Research (CBER)

Text Version... people in the US and costing approximately $13.4 ... Healthcare Cost and Utilization Project (HCUP). ... is from the Centers for Medicare and Medicaid ... More results from


Appendix A: Hip Implant Device Utilization in the U  

Center for Biologics Evaluation and Research (CBER)

Text VersionPage 1. 1 Appendix C: General Overview of Section 522 Studies Postmarket Surveillance Studies Under Section 522 Postmarket ... More results from


Effect of cement fill ratio in loosening of hip implants.  


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 2 to 5 mm 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


Appendix A: Hip Implant Device Utilization in the U  

Center for Biologics Evaluation and Research (CBER)

Text Version... than 0.81. Study Population Description Study population is as per device indication. Sample Size 160 procedures Data ... More results from


Goserelin Implant  


... as an implant to be inserted with a syringe subcutaneously (under the skin) in your stomach area ... written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as ...


Carmustine Implant  


Carmustine implant is used along with surgery and sometimes radiation therapy to treat malignant glioma (a certain type of cancerous brain tumor). Carmustine is in a class of medications called alkylating agents. It works by slowing or stopping ...


The reliability of hip scoring systems for total hip arthroplasty candidates: assessment by physical therapists  

Microsoft Academic Search

Objective: Hip rating systems have been widely used in assessing severity of hip dysfunction but no uniform method has emerged. The current study was performed to determine the interobserver reliability of five different hip scores on patients with coxarthrosis.Design: Test reliability among physical therapists for five commonly used hip scores.Subjects: Thirty-five patients (48 hips) who had coxarthrosis and who were

Linda Kirmit; Vasfi Karatosun; Bayram Unver; Serkan Bakirhan; Ayse Sen; Zeliha Gocen



The long-term clinical relevance of calcar atrophy caused by stress shielding in total hip arthroplasty  

Microsoft Academic Search

Eighty osteoarthritic female patients were randomly allocated to 4 equal groups; the Zwey-Muller, the Corail, the Optifix, or Autophor 900S cementless total hip arthroplasties (THAs) were implanted; and bone density changes, at different sites, were prospectively studied. In zone 7, the greatest reduction of bone density values was observed at 2 years (group A: 24%, group B: 8%, group C:

Theofilos Karachalios; Christos Tsatsaronis; George Efraimis; Panagiotis Papadelis; George Lyritis; George Diakoumopoulos



The relationship between stress shielding and bone resorption around total hip stems and the effects of flexible materials  

Microsoft Academic Search

Bone resorption around hip stems is a disturbing phenomenon, although its clinical significance and its eventual effects on replacement longevity are as yet uncertain. The relationship between implant flexibility and the extent of bone loss, frequently established in clinical patient series and animal experiments, does suggest that the changes in bone morphology are an effect of stress shielding and a

HWJ Huiskes; HARRIE WEINANS; Rietbergen van R



Anterior iliopsoas impingement after total hip arthroplasty  

Microsoft Academic Search

Pain after total hip arthroplasty (THA) can be caused by a multitude of conditions, including infection, aseptic loosening, heterotopic ossification, and referred pain. It is also recognized that soft tissue inflammation about the hip, such as trochanteric bursitis, can lead to hip pain after THA. Two cases of persistent iliopsoas tendinitis following THA are reported, which are believed to be

Robert T. Trousdale; Miguel E. Cabanela; Daniel J. Berry



Another look at the australopithecine hip  

Microsoft Academic Search

The climbing ability and locomotor efficiency of australopithecine species, particularlyAustralopithecus afarensis, remain controversial despite decades of research. The hip joint is an informative area of anatomy in this regard: determination of relative hip mobility contributes significantly to reconstructing climbing ability, because a mobile hip joint is useful in navigating discontinuous arboreal substrates. This study quantified the distribution of subchondral bone

Laura M. MacLatchy



[Traumatic hip dislocation in childhood].  


The article reports on eight cases of traumatic dislocation of the hip in children. Six of these were genuine dislocations and two dislocation fractures. The children were between 5 and 13 years of age at the time of injury. Seven of these 8 children could be followed up one to 21 years after the accident. All 7 children were free from complaints at the time of follow-up examination; in one case only we found a moderate loss of function in the injured hip joint. In this patient the x-ray film showed deformation of the head of the femur after partial necrosis of the femoral head, as well as initial signs of coxarthrosis. Prognosis of this rare injury in children is favourable if repositioning is performed in time and if relief of the hip is effected for the proper period of time, depending on the individual case. PMID:2665382

Stachel, P; Hofmann-v Kap-herr, S; Schild, H



[Update on total hip arthroplasty].  


Total hip arthroplasty (THA) is one of the most common surgical procedures performed by orthopedic surgeons. Frequent indications for THA include osteoarthrosis of the hip joint that can be primary origin or secondary to dysplasia or traumatic origin, as well as fractures of the femoral neck in active patients. Other common indications include rheumatoid arthritis and osteonecrosis of the femoral head. It is a surgical intervention giving very good results giving patients pain relief and mobility with a success rate in more than 90% of cases. The point of this article is to inform the medical community on the actual situation of hip prosthetics in fields including epidemiology, clinical results, indications, contraindications, different types of prosthetic materials as well as surgical approaches. PMID:21250424

Christofilopoulos, Panayiotis; Lübbeke, Anne; Peter, Robin; Hoffmeyer, Pierre



Unpredictability of hip behavior in Dyggve-Melchior-Clausen syndrome: A mid-term assessment of siblings.  


Dyggve-Melchior-Clausen syndrome is a rare spondylo-epiphyseal disease, which almost constantly leads to both bilateral hip degeneration and dislocation. Few authors have reported to date the surgical management of this orthopaedic disorder. We present two new cases affecting siblings. One brother was treated by unilateral triple pelvic osteotomy combined with varus osteotomy of the proximal femur; the other was treated by bilateral Pemberton osteotomies with varus osteotomy of the proximal femur. At a respective 5-year and 3-year follow-up delay, both cases had evolved towards progressive subluxation recurrence along with severe hip degeneration. Based on both our experience and literature review, it seems that one should avoid operating these hips unless pain renders surgery mandatory. Total hip arthroplasty seems the only reliable surgical solution at the adult age and paediatric surgeons should keep in mind that previous femoral osteotomies will make it more challenging for adult orthopaedic surgeons to implant on a remodeled anatomy. PMID:24035654

Nectoux, E; Hocquet, B; Fron, D; Mezel, A; Paris, A; Herbaux, B



Effect of component design in retrieved bipolar hip hemiarthroplasty systems.  


Primary articulation of bipolar hemiarthroplasty systems is at the femoral head-liner interface. The purpose of this study was to compare observed damage modes on 36 retrieved bipolar systems with implant, demographic, intraoperative, and radiographic data to elucidate the effects of component design, specifically locking mechanism, on clinical performance. Retrieved bipolar hip hemiarthroplasty systems of 3 different design types were obtained, disassembled, and evaluated macro- and microscopically for varying modes of wear, including abrasion, burnishing, embedding, scratching, and pitting. Clinical record review and radiographic analysis were performed by a senior orthopedic surgery resident. Average bipolar hip hemiarthroplasty system term of service was 46 months (range, 0.27-187 months). All devices contained wear debris captured within the articulating space between the femoral head and liner. In 31% of patients without infection, lucency was observed on immediate prerevision radiographs. The system with a leaf locking mechanism showed significantly increased radiographically observed osteolysis (P=.03) compared with a system with a stopper ring locking mechanism. In addition, implant design and observed damage modes, including pitting and third-body particle embedding, were significantly associated with radiographically observed osteolysis. PMID:24025011

Hess, Matthew D; Baker, Erin A; Salisbury, Meagan R; Kaplan, Lige M; Greene, Ryan T; Greene, Perry W



Investigations on the galvanic corrosion of multialloy total hip prostheses.  


Total hip prostheses combining cobalt and titanium alloys in direct physical contact are currently being used. The purpose of this paper was to investigate the possibility of an accelerated corrosion occurring due to the coupling of these alloys. Electrochemical corrosion studies based on mixed potential and protection potential theories were used to study the in vitro effects of coupling the titanium and cobalt alloys. Verification of these studies was made by direct coupling experiments. Macroscopic examination of' surface features of four retrieved total hip prostheses ranging from 0-6 years implantation were conducted. The electrochemical studies predicted coupled corrosion potentials of -0.22 V and low coupled corrosion rates of 0.02 microA/cm2. Direct coupling experiments verified these results. Cobalt-titanium interfaces on the implants were macroscopically examined, and no instances of extensive corrosion were found. Overall, the in vitro corrosion studies and the examination of retrieved prostheses predicted no exaggerated in vivo corrosion due to the coupling of these cobalt and titanium alloys. PMID:12659138

Lucas, L C; Buchanan, R A; Lemons, J E



The stubborn hip: Idiopathic avascular necrosis of the hip  

Microsoft Academic Search

Objective: To highlight the unusually indolent course of avascular necrosis in this patient, the risk factors of which chiropractors should be aware, the necessity of and means to an early diagnosis, the limitations of plain film radiographs, as well as the current medical treatments. Clinical Features: A 27-year-old male professional soccer player had a tight and achy right hip for

Jason A. Pajaczkowski



Acetabular considerations during total hip arthroplasty for hip dysplasia.  


The wide spectrum of anatomic abnormalities that characterize hip dysplasia dictate the need for different reconstructive techniques when hip replacement is required. Multiple factors such as young age and high activity level of this patient population, coupled with the increased complexity of surgery, explain the somewhat elevated historical failure rate of hip arthroplasty in DDH and emphasize the need for careful analysis of each case and selection of the most appropriate reconstruction options. One particular problem specific to acetabular reconstruction is the deficient bone stock that may limit the ability to place the component fully on native bone at the true acetabular region. When standard techniques of reconstruction leave a significant portion of the component uncovered, the alternatives include acetabular augmentation with bone autograft, intentional high placement of the component, or medialization of the component with or without medial wall osteotomy. Uncemented sockets have provided promising midterm results with supplemental bone augmentation and are the authors' preferred method of treatment for hips with moderate dysplasia and anterolateral acetabular bone deficiency. PMID:22819164

Dapuzzo, Michele R; Sierra, Rafael J



The susceptibility of smooth implant surfaces to periimplant fibrosis and migration of polyethylene wear debris.  


The purpose of this investigation was to establish whether the tissue response and migration of polyethylene debris differed at noncemented smooth and porous implant surfaces. This was accomplished through 3 separate but closely related studies: (1) a canine cylindrical implant model with smooth and porous surfaces exposed to polyethylene debris; (2) a canine total hip arthroplasty model analyzing the interface between bone and femoral implants with various porous-coating configurations; and (3) a histologic analysis of autopsy-retrieved, human, noncemented hip prostheses with noncircumferential porous coating. The cylindrical implant model involved the placement of split cylinders, 1/2 porous and 1/2 smooth, into the distal femur and proximal tibia of 4 dogs. Four control implants and 10 test implants (chronically exposed to simulated polyethylene debris with a mean size of 4.7 microns) were examined histologically as long as 30 weeks after surgery. The canine hip study involved the study of 54 noncemented hip prostheses at periods of 1, 6, and 24 months. The prostheses possessed 4 different porous surface configurations: 1 with circumferential porous coating, 2 with noncircumferential coating, and 1 without porous coating. The human retrieval analysis involved the study of 7 cadaveric femora (age, 6 months-5 years) implanted with a straight titanium-alloy prosthesis possessing proximal pads of titanium fiber metal on the anterior, posterior, and medial aspects. With all implants in all 3 studies, there was the common finding of bone ingrowth at the porous implant surface and a fibrous interface or periprosthetic cavity around the portion of the implant that was smooth surfaced. The periprosthetic cavity typically was encapsulated by a thin continuous shell of trabecular bone. In addition, polyethylene debris was found to have preferentially migrated along the smooth implant surfaces. In the longer-term canine and human hip retrievals, polyethylene particles in the micron size range were present within histiocytes, whereas larger particles as much as 100 microns were found within foreign-body giant cells. Of importance for the implants from all 3 studies, with the exception of some pronounced cavities on the lateral aspect of the human hip prostheses, the periimplant cavities around the smooth surfaces were not detectable radiographically. This study clearly established a fundamental principle of relative barriers to particulate debris migration. Smooth implant surfaces are more susceptible than porous surfaces to the development of a fibrous tissue filled periimplant cavity and the subsequent migration of polyethylene wear debris.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:7634577

Bobyn, J D; Jacobs, J J; Tanzer, M; Urban, R M; Aribindi, R; Sumner, D R; Turner, T M; Brooks, C E



Factors correlating with long term survival of McKee-Farrar total hip prostheses.  


Clinical and radiographic evaluations of 15 McKee-Farrar hip replacements in 13 patients with followup of 21 to 26 years were performed. The average Harris hip score was 86 with no patients having a poor result. These patients outscored the age matched controls in all categories of the SF-36 health survey. All patients were community ambulators with qualitative activity levels exceeding the average for their age. Quantitative activity assessment with a pedometer in 3 patients indicated a current average of approximately 900,000 cycles per year. This represents more than 21 million cycles when extrapolated during the life of the implants. None of the femoral components were radiographically loose. One acetabular component may be loose. Osteolysis developed in 3 apparently well fixed femurs and in 1 acetabulum. There were several features of these cases that may have contributed to the long survival: (1) relatively small stature of the patients who averaged 160.5 cm (5 feet 5 inches) in height and 66.9 kg (147 lbs) in weight; (2) favorable biomechanics of the reconstruction with the hip center of rotation being medialized by an average of 6.4 mm and the femoral offset increased by an average of 4.9 mm; (3) decreased potential for neck socket impingement with an average lateral acetabular opening of 54 degrees and all components were anteverted; (4) radiolucent cement in 13 of 15 hips; and (5) no radiographically measurable wear. Previous analyses and comparisons of the clinical performance of the McKee-Farrar implant have focused on the metal on metal bearing. As has been recognized with the many variations of total hip replacement using metal on plastic hearings, there are a myriad of variables that contribute to clinical outcome. The results of this study suggest that patient selection and technical factors may contribute to the long term survival, and conversely to the failure, of McKee-Farrar implants. PMID:8769322

Schmalzried, T P; Szuszczewicz, E S; Akizuki, K H; Petersen, T D; Amstutz, H C



Total hip arthroplasty in the young: special emphasis on post-SCFE patients.  


Slipped capital femoral epiphysis (SCFE) is a hip disorder of adolescence, which has the potential for profound implications into adulthood. SCFE patients are at risk of early joint degeneration and subsequent need for arthroplasty. The rate at which arthroplasty is required is not precisely known, but is estimated to be approximately 45% by 50 years after a slip. The femoral neck and shaft displace anteriorly and rotate externally relative to the femoral epiphysis, which remains fixed in the acetabulum. Stabilization of the physis is the goal of acute management. Despite such efforts, accelerated joint degeneration may occur over time. This progression is due to avascular necrosis, chondrolysis, or following years of femoroacetabular impingement. Total hip arthroplasty (THA) and total hip resurfacing (THR) are options for end-stage hip arthritis due to SCFE. THR is technically more challenging, with very limited ability to address deformity-related issues of impingement, decreased hip offset, and trochanteric malposition. THR, as in any metal on metal arthroplasty, may be associated with local metal sensitivity or systemic metal toxicity. Given the limited utility and potential risks, THR is currently not recommended in the majority of cases. THA, although historically demonstrating poor long-term implant performance in the young patient, has become a more reliable option recently. The potential benefits of THA are considerable, even for the young patient with end-stage hip degeneration. Certain cemented and many cementless stem designs show good long-term survival, as do current cementless cups. Advances in bearing surfaces promise to minimize wear and extend implant longevity. Ceramic on ceramic, metal on highly cross-linked polyethylene, and ceramic on highly cross-linked polyethylene bearing couples offer promise. PMID:23764787

Nelms, Nathaniel J; Lewallen, Laura W; McIntosh, Amy L; Sierra, Rafael J


Acetabular blood flow during total hip arthroplasty  

PubMed Central

Objective To determine the immediate effect of reaming and insertion of the acetabular component with and without cement on periacetabular blood flow during primary total hip arthroplasty (THA). Design A clinical experimental study. Setting A tertiary referral and teaching hospital in Toronto. Patients Sixteen patients (9 men, 7 women) ranging in age from 30 to 78 years and suffering from arthritis. Intervention Elective primary THA with a cemented (8 patients) and noncemented (8 patients) acetabular component. All procedures were done by a single surgeon who used a posterior approach. Main outcome measure Acetabular bone blood-flow measurements made with a laser Doppler flowmeter before reaming, after reaming and after insertion of the acetabular prosthesis. Results Acetabular blood flow after prosthesis insertion was decreased by 52% in the noncemented group (p < 0.001) and 59% in the cemented group (p < 0.001) compared with baseline (prereaming) values. Conclusion The significance of these changes in periacetabular bone blood flow during THA may relate to the extent of bony ingrowth, periprosthetic remodelling and ultimately the incidence of implant failure because of aseptic loosening.

ElMaraghy, Amr W.; Schemitsch, Emil H.; Waddell, James P.



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


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. Cite this article: Bone Joint J 2013;95-B:1538-43. PMID:24151276

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



Impact of ZnO embedded feed spacer on biofilm development in membrane systems.  


The concept of suppressing biofouling formation using an antibacterial feed spacer was investigated in a bench scale-cross flow system mimicking a spiral wound membrane configuration. An antibacterial composite spacer containing zinc oxide-nanoparticles was constructed by modification of a commercial polypropylene feed spacer using sonochemical deposition. The ability of the modified spacers to repress biofilm development on membranes was evaluated in flow-through cells simulating the flow conditions in commercial spiral wound modules. The experiments were performed at laminar flow (Re = 300) with a 200 kDa molecular weight cut off polysulfone ultrafiltration membrane using Pseudomonas putida S-12 as model biofilm bacteria. The modified spacers reduced permeate flux decrease at least by 50% compared to the unmodified spacers (control). The physical properties of the modified spacer and biofilm development were evaluated using high resolution/energy dispersive spectrometry-scanning electron microscopy, atomic force microscopy and confocal laser scanning microscopy imaging (HRSEM, EDS, AFM and CLSM). HRSEM images depicted significantly less bacteria attached to the membranes exposed to the modified spacer, mainly scattered and in a sporadic monolayer structure. AFM analysis indicated the influence of the modification on the spacer surface including a phase change on the upper surface. Dead-live staining assay by CLSM indicated that most of the bacterial cells attached on the membranes exposed to the modified spacer were dead in contrast to a developed biofilm which was predominant in the control samples. PMID:24079967

Ronen, Avner; Semiat, Raphael; Dosoretz, Carlos G



Atomic Layer Deposition of SiN for spacer applications in high-end logic devices  

NASA Astrophysics Data System (ADS)

Continuous down scaling of transistor size resulted in introduction of high-k material to replace the conventional gate oxide. High-k Metal Gate implementation brings new challenges to the subsequent processing steps of the device. Both oxide ingress and removal of the HKMG stack during later cleaning steps must strictly be avoided. We have developed and optimized an ALD SiN encapsulation liner which protects the HKMG stack and also serves as a robust spacer for subsequent ion implantation. SiN was chosen because of its oxide-blocking characteristics and its durability in diluted hydrofluoric acid. We developed sophisticated ALD processes using ionized ammonia radicals and dichloro-silane. This ALD process has several advantages compared to conventional LPCVD or PECVD processes: Superior thickness control and uniformity, excellent step coverage and no loading effects. In addition, process temperature could be reduced to 500°C, which is shown to be critical for protecting the HKMG stack. Further reduction in process temperature to 400°C is also demonstrated using a novel precursor.

Koehler, F.; Triyoso, D. H.; Hussain, I.; Mutas, S.; Bernhardt, H.



Hip: Anatomy and US technique  

PubMed Central

Ultrasound (US) has always had a relatively limited role in the evaluation of the hip due to the deep location of this joint. However, many hip diseases are well detectable at US, but before approaching such a study it is necessary to be thoroughly familiar with the normal anatomy and related US images. The study technique is particularly important as optimization of various parameters is required, such as probe frequency, focalization, positioning of the probe, etc. Also the patient’s position is important, as it varies according to the area requiring examination. For the study of the anterior structures, the patient should be in the supine position; for the medial structures, the leg should be abducted and rotated outward with the knee flexed; for the lateral structures, the patient should be in the controlateral decubitus position; for the posterior structures the patient must be in the prone position. US study of the hip includes assessment of the soft tissues, tendons, ligaments and muscles, and also of the bone structures, joint space and serous bursae. The purpose of this article is to review the normal anatomy of the hip as well as the US anatomy of this joint.

Molini, L.; Precerutti, M.; Gervasio, A.; Draghi, F.; Bianchi, S.



Developmental dysplasia of the hip  


The hip is a ball and socket joint. The ball, called the femoral head, forms the top part of the thigh bone (femur) and the ... newborns, the socket is too shallow and the ball (thigh bone) may slip out of the socket, ...


Orgaran in Hip Fracture Surgery  

Microsoft Academic Search

Two studies evaluating the effect of Orgaran prophylaxis on the incidence of postoperative thrombosis in hip fracture surgery are reported. In one Scandinavian study, dextran was used in the comparative group, and in the US study, warfarin was used. In both, Orgaran was significantly more effective in reducing the frequency of deep vein thrombosis without producing an increase in bleeding

David Bergqvist



[Pyomyositis of hip obturator muscles].  


Obturator internus muscle abscess (pyomyositis) is extremely rare in temperate environments, although there has been a recent reported increase in prevalence. There usually is a delay in diagnosis and onset of treatment. In addition to our case, we reviewed all cases of pyomyositis of hip muscles found in a review of the recent medical literature. PMID:17352115

Downey Carmona, F J; Farrington Rueda, D



Electrostimulation of Bone Defects in Total Hip Revision in Triple Layered Domains  

Microsoft Academic Search

\\u000a Electrostimulation is indicated for fracture healing and the treatment of avascular necrosis of the femoral head. In the present\\u000a work a new concept was developed to implement the option of electrostimulation in the reconstruction of acetabular bone defects\\u000a in case of revision of the total hip replacement providing improved implant fixation at the surrounding bone stock. In specific\\u000a revision situations

C. Potratz; R. Souffrant; R. Bader; W. Mittelmeier; U. van Rienen


Biological fixation of hydroxyapatite-coated versus grit-blasted titanium hip stems: a canine study  

Microsoft Academic Search

Background. The purpose of the study was to evaluate the influence of a proximal hydroxyapatite (HA) coating in comparison with a grit-blasted titanium surface of an anatomic hip stem in an animal model over a maximum duration of 2 years. Methods. Thirty adult dogs underwent implantation of either a proximally HA-coated or a grit-blasted anatomic titanium stem. The animals were

Anke Eckardt; Harold M. Aberman; Dan H. Cantwell; Jochen Heine



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



The dimensional accuracy for preparation of the femoral cavity in HIP arthroplasty  

Microsoft Academic Search

Introduction: The aim of the study was to determine the precision of the preparation of the femoral cavity in cementless hip arthroplasty.\\u000a We compared the bone–prosthesis interface after manual- and robot-assisted implantation of the stems. Material and methods: After plastination the specimens were cut to slices of 2.5 mm and documented by microradiography. The interface between\\u000a prosthesis and bone was measured

Marcel Prymka; Lidong Wu; Hans-Jürgen Hahne; Jürgen Koebke; Joachim Hassenpflug



Periprosthetic Malignancy as a Mode of Failure in Total Hip Arthroplasty  

Microsoft Academic Search

The presence of periprosthetic malignancy in proximity to arthroplasty implants has been infrequently reported. We present the clinical, radiographic, and pathological features of three patients in whom loosening and failure of total hip arthroplasties occurred secondary to malignant infiltration. They consisted of a 66-year-old man with the first presentation of metastatic gastric carcinoma as a periacetabular lytic lesion, a 64-year-old

Kieran O'Shea; Stephen R. Kearns; Anya Blaney; Paraic Murray; Hugh A. Smyth; John P. McElwain



Alumina-on-Alumina Hip Arthroplasty in Patients Younger Than 30 Years Old  

Microsoft Academic Search

THA in patients younger than 30 years old presents challenges: the initial technical challenge relates to the initial disease\\u000a that often causes deformities making reconstruction difficult, while the long-term challenge is wear and subsequent osteolysis\\u000a and component loosening. Ceramic-on-ceramic prostheses may represent a valuable option to reduce wear. We retrospectively\\u000a studied 101 patients (132 hips) with ceramic-on-ceramic prostheses implanted from 1977

R. Nizard; D. Pourreyron; A. Raould; D. Hannouche; L. Sedel



Expression of tenascin-C in aseptic loosening of total hip replacement  

Microsoft Academic Search

OBJECTIVETo assess if the bonding interlayer between the implant and bone in aseptic loosening of total hip replacement (THR) is qualitatively deteriorated by excessive accumulation of anti-adhesive glycoprotein, tenascin-C.METHODSAlkaline phosphatase-anti-alkaline phosphatase (APAAP) method was used for immunohistochemical staining of tenascin-C in interface tissue and control synovial tissue.RESULTSTenascin-C was found to be a major component of the extracellular matrix at a

Yrjö T Konttinen; Tian-Fang Li; Oliver Michelsson; Jing-Wen Xu; Timo Sorsa; Seppo Santavirta; Shinji Imai; Ismo Virtanen



Idiopathic chondrolysis of the hip.  


The cases of nine patients (eleven hips) with idiopathic chondrolysis of the hip were studied. Seven of the patients were white and two were Hispanic. The age at onset ranged from eight to sixteen years (mean, 11.5 years). Four patients were boys and five were girls. All patients had a decreased passive range of motion of the hip, and radiographic examination showed regional osteoporosis, premature closure of the femoral capital physis, narrowing of the joint space, and lateral overgrowth of the femoral head on the neck. All laboratory examinations were negative for evidence of infection or rheumatoid arthritis. An arthrotomy was done in seven patients. Specimens of the synovial tissue showed no growth on culture, and the histological studies revealed only minimum signs of inflammation. Histological studies of the articular cartilage were normal. Treatment consisted of administration of acetylsalicylic acid in therapeutic dosages to maintain a blood salicylate level of fifteen to twenty-five milligrams per cent, active non-loading exercise of the hip, protected weight-bearing with crutches, short-term traction to overcome or relieve contractures after biopsy, iliopsoas tenotomy or lengthening in three patients, and an adductor myotomy in one patient. At follow-up, 2.3 to 9.4 years after onset (mean, 6.2 years), six patients had either no symptoms or only minor intermittent discomfort in the hip. On radiographic examination, although these six patients had restoration of the joint space they did have lateral overgrowth of the femoral head (lateral buttressing) and overgrowth of the lateral acetabular margin (lateral osteophyte). In three patients who had disabling pain, joint deterioration was evident on the radiographic examination. One of these patients had a resurfacing arthroplasty to relieve pain. PMID:6654940

Bleck, E E



Osteocyte deficiency in hip fractures.  


Osteocytes play a central role in the regulation of bone remodeling. The aim of this study was to explore osteocyte function, and particularly the expression of SOST, a Wnt inhibitor, in patients with hip fractures. Serum sclerostin levels were measured by ELISA. The expression of several osteocytic genes was studied by quantitative PCR in trabecular samples of the femoral head of patients with hip fractures, hip osteoarthritis and control subjects. The presence of sclerostin protein and activated caspase 3 was revealed by immunostaining. There were no significant differences in serum sclerostin between the three groups. Patients with fractures have fewer lacunae occupied by osteocytes (60 ± 5% vs. 64 ± 6% in control subjects, P = 0.014) and higher numbers of osteocytes expressing activated caspase 3, a marker of apoptosis. The proportion of sclerostin-positive lacunae was lower in patients with fractures than in control subjects (34 ± 11% vs. 69 ± 10%, P = 2 × 10(-8)). The proportion of sclerostin-positive osteocytes was also lower in patients. RNA transcripts of SOST, FGF23 and PHEX were also less abundant in fractures than in control bones (P = 0.002, 5 × 10(-6), and 0.04, respectively). On the contrary, in patients with osteoarthritis, there was a decreased expression of SOST and FGF23, without differences in PHEX transcripts or osteocyte numbers. Osteocyte activity is altered in patients with hip fractures, with increased osteocyte apoptosis and reduced osteocyte numbers, as well as decreased transcription of osteocytic genes. Therefore, these results suggest that an osteocyte deficiency may play a role in the propensity to hip fractures. PMID:21874545

Delgado-Calle, Jesús; Arozamena, Jana; García-Renedo, Raúl; García-Ibarbia, Carmen; Pascual-Carra, María A; González-Macías, Jesús; Riancho, José A



Ultrasound-Guided Hip Arthrocentesis in a Child with Hip Pain and Fever  

PubMed Central

Children presenting to the emergency department with hip pain and fever are at risk for significant morbidity due to septic arthritis. Distinguishing between septic arthritis and other causes of hip pain may be challenging. Sonographic visualization of the hip with real-time ultrasound-guided arthrocentesis may allow faster differentiation between etiologies, hastening definitive therapy and improving analgesia. This report describes the use of hip sonography in a case of Lyme arthritis. The authors review the medical literature in support of bedside hip sonography and discuss how to perform ultrasound-guided hip arthrocentesis. Clinical findings in septic and Lyme arthritis are also described.

Moak, James H.; Vaughan, Aaron J.; Silverberg, Benjamin A.



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



Surface micro-analyses of long-term worn retrieved "Osteal" alumina ceramic total hip replacement.  


We analyzed wear pattern of long-term retrieved alumina-alumina hip prostheses from Osteal, which were implanted for 15-19 years. A comparison was carried out with our previous study of 17-year Biolox alumina-on-alumina hip prostheses, (Shishido et al., J Biomed Mater Res B 2003;67:638-647) and all-alumina total hip replacement run under microseparation simulator tests. Of particular interest was the occurrence of stripe wear in these first generation alumina ceramic bearings. Two balls of Osteal revealed only one stripe wear as did the respective liners on their rim areas. In these latter balls, the stripes were shallower than those previously observed in Biolox implants. A microscopic analysis of the bearing surface was carried out using scanning electron microscopy and fluorescence microprobe spectroscopy. On average, the Osteal retrievals had one grade lower wear than Biolox retrievals. Fluorescence microprobe maps showed that Biolox ball surfaces had higher compressive stress than the Osteal likely due to severe impingement and microseparation promoted by the bulky implant design. PMID:17455269

Tateiwa, Toshiyuki; Clarke, Ian C; Pezzotti, Giuseppe; Sedel, Laurent; Kumakura, Tsuyoshi; Shishido, Takaaki; Yamamoto, Kengo



Intramedullary rod and cement static spacer construct in chronically infected total knee arthroplasty.  


Two-stage reimplantation, with interval antibiotic-impregnated cement spacer, is the preferred treatment of prosthetic knee joint infections. In medically compromised hosts with prior failed surgeries, the outcomes are poor. Articulating spacers in such patients render the knee unstable; static spacers have risks of dislocation and extensor mechanism injury. We examined 58 infected total knee arthroplasties with extensive bone and soft tissue loss, treated with resection arthroplasty and intramedullary tibiofemoral rod and antibiotic-laden cement spacer. Thirty-seven patients underwent delayed reimplantation. Most patients (83.8%) were free from recurrent infection at mean follow-up of 29.4 months. Reinfection occurred in 16.2%, which required debridement. Twenty-one patients with poor operative risks remained with the spacer for 11.4 months. All patients, during spacer phase, had brace-free ambulation with simulated tibiofemoral fusion, without bone loss or loss of limb length. PMID:21783338

Kotwal, Suhel Y; Farid, Yasser R; Patil, Suresh S; Alden, Kris J; Finn, Henry A



Complications of Hip Arthroscopy: Analysis of Seventy Three Cases  

Microsoft Academic Search

Background: Hip arthroscopy is recognized as a highly effective means of treating joint disorders. Complications in hip arthroscopy, including neurovascular traction injury, compression injury to the perineum and scope trauma, have been reported. We report our experience with 73 hip arthroscopy procedures and complications at Chang Gung Memorial Hospital. Methods: Seventy-two patients with 73 hips with severe hip pain were

Yang-Pin Lo; Yi-Sheng Chan; Li-Chang Lien; Mel S-S Lee; Kuo-Yao Hsu; Chun-Hsiung Shih


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



Minimally invasive dynamic hip screw for fixation of hip fractures  

PubMed Central

We compared a minimally invasive surgical technique to the conventional (open approach) surgical technique used in fixation of hip fractures with the dynamic hip screw (DHS) device. Using a case-control design (44 cases and 44 controls), we tested the null hypothesis that there is no difference between the two techniques in the following outcome measures: duration of surgery, time to mobilisation and weight bearing postoperatively, length of hospital stay, mean difference of pre- and postoperative haemoglobin levels, position of the lag screw of the DHS device in the femoral head, and the tip–apex distance. The minimally invasive DHS technique had significantly shorter duration of surgery and length of hospital stay. There was also less blood loss in the minimally invasive DHS technique. The minimally invasive DHS technique produces better outcome measures in the operating time, length of hospital stay, and blood loss compared to the conventional approach while maintaining equal fixation stability.

Ho, Michael; Garau, Giorgio; Walley, Gayle; Oliva, Francesco; Panni, Alfredo Schiavone; Longo, Umile Giuseppe



Short Term Clinical Outcome of a Porous Tantalum Implant for the Treatment of Advanced Osteonecrosis of the Femoral Head  

PubMed Central

Purpose of the study: Osteonecrosis of the hip mostly affects young individuals and often progresses to a debilitating disease. Several treatment modalities exist, but none are completely satisfactory. This study evaluates the clinical outcome of patients treated with core decompression and insertion of a porous tantalum implant in the femoral head. This procedure is similar to commonly performed procedures, but has the additional advantages of providing structural support to the necrotic femoral head while having no donor-site morbidity. Methods: We evaluated 15 patients with 18 osteonecrotic hips with Steinberg stage III (3 hips) and IV (15 hips) disease. The mean age of the patients was 42 years-old (eldest 66), and the mean time for follow-up was 23 months. The outcome measure was hip function, evaluated with the Harris hip score, and the end point was total hip arthroplasty, or referral for this procedure. Results: The success rate at twelve months postoperatively was 77.8%, and the overall success rate was 44.5%. Failures occurred at a mean time of 11.7 months, and one complication, a periprosthetic fracture, occurred 4 months postoperatively. On average, patients who did well improved their Harris hip scores by 21.7 points, and patients who eventually required arthroplasty decreased their scores by 14 points. Conlusions: Core decompression with porous tantalum implants showed encouraging success rates and early clinical results in patients with advanced stage osteonecrosis, but further larger scale studies are required to identify the population best suited for this procedure.

Nadeau, Melissa; Seguin, Chantal; Theodoropoulos, John S; Harvey, Edward J



Subsequent Hip Fracture in Osteoporotic Hip Fracture Patients  

PubMed Central

Purpose A significant number of patients who have experienced previous surgical treatment for an osteoporotic hip fracture experience a subsequent hip fracture (SHF) on the opposite side. This study aims to analyze the risk factors and the correlation between osteoporosis and SHF on the opposite side in order to assess the usefulness of bisphosphonate treatment for the prevention of SHFs. Materials and Methods We included 517 patients treated from March 1997 to April 2009 in this study. The inclusion criteria included previous unilateral hip fracture, without osteoporotic treatment, and a T-score less than -3.0 at the time of the fracture. We studied these patients in terms of death, SHF, alcoholism, living alone, dementia, dizziness, health status, osteoporotic treatment after fracture and bone mineral density (BMD). In total, 34 patients experienced a SHF. We selected another 34 patients without a SHF who had similar age, sex, body mass index, BMD, diagnosis, treatment and a follow up period for a matched pair study. We compared these two groups. The average follow up was 8.3 years and 8.1 years, respectively. Results The mortality rate of the 517 patients was 138 (27%). The BMD at the time of fracture demonstrated no statistical difference between the two groups (p>0.05). Nine patients (26%) within the SHF group were prescribed Risedronate and 18 patients (53%) received the same treatment in the non-SHF group. There was a statistical relationship with the treatment of osteoporosis (p=0.026). The average BMD of patients with SHF was -5.13 and -5.02 in patients without SHF was (p>0.05). Conclusion Although primary surgical treatments are important for an excellent outcome in osteoporotic hip fractures, treatment of osteoporosis itself is just as important for preventing SHFs.

Lee, Sang Ho; Lee, Tong Joo; Cho, Kyu Jung; Shin, Sang Hyun



Cochlear Implants  


... In With a Cochlear Implant This type of hearing loss is sensorineural , which means there is damage to the tiny hair cells in the part of the inner ear called the cochlea. Because of this damage, ... or “cured” hearing. It does, however, allow for the perception of ...


Packaging design criteria modified fuel spacer burial box. Revision 1  

SciTech Connect

Various Hanford facilities must transfer large radioactively contaminated items to burial/storage. Presently, there are eighteen Fuel Spacer Burial Boxes (FSBBs) available on the Hanford Site for transport of such items. Previously, the FSBBS were transported from a rail car to the burial trench via a drag-off operation. To allow for the lifting of the boxes into the burial trench, it will be necessary to improve the packagings lifting attachments and provide structural reinforcement. Additional safety improvements to the packaging system will be provided by the addition of a positive closure system and package ventilation. FSBBs that are modified in such a manner are referred to as Modified Fuel Spacer Burial Boxes (MFSBs). The criteria provided by this PDC will be used to demonstrate that the transfer of the MFSB will provide an equivalent degree of safety as would be provided by a package meeting offsite transportation requirements. This fulfills the onsite transportation safety requirements implemented in WHC-CM-2-14, Hazardous Material Packaging and Shipping. A Safety Analysis Report for Packaging (SARP) will be prepared to evaluate the safety of the transfer operation. Approval of the SARP is required to authorize transfer. Criteria are also established to ensure burial requirements are met.

Stevens, P.F.



Alignment tool for spacers of nuclear reactor fuel assemblies  

SciTech Connect

Alignment tool is described for the remotely controlled recalibration of resilient protruding contact dimples or springs in substantially square spacer grid meshes of nuclear reactor fuel assemblies, including an outer centering tube adapted to the cross section of a spacer mesh and rigid and resilient contact dimples protruding into the interior of the mesh in given directions, the outer centering tube having a window formed therein in the vicinity of the contact dimple, a gripper-actuating tube being concentrically surrounded by and axially movable within the outer centering tube, a pendulum rod having a free end and being disposed in the interior of the gripper-actuating tube and being axially fixed relative to the gripper-actuating tube and able to oscillate in the given protrusion direction of the resilient contact dimple to be recalibrated, a gripper attached to the free end of the pendulum rod, a restoring spring for exerting pressure on the gripper, and a run-on incline formed on the pendulum rod being engageable with the gripper-actuating tube over and above the contact dimple for radial displacement of the gripper against the pressure of the restoring spring.

Knecht, K.; Gebhard, G.; Rohr, F.



Using the Diffractive Optics for 3D Inspection of Nuclear Reactor Fuel Assembly Grid Spacers  

NASA Astrophysics Data System (ADS)

Ensuring the safety and high operation reliability of nuclear reactors takes 100% inspection of geometrical parameters of fuel assemblies, which include the grid spacers fabricated as cellular structure with fuel elements. The required grid spacers' geometry of assembly in the transverse and longitudinal cross sections is extremely important for maintaining the necessary heat regime. A universal method for 3D grid spacer inspection using the diffractive optical element, which generates, as the structured light, a multiple-ring pattern on the inner surface of a grid spacer cell is investigated. The experimental measurement error for cell centers position deviation is ±7 ?m, and the error for overall dimensions is ±11 ?m.

Finogenov, L. V.; Lemeshko, Yu. A.; Zav'yalov, P. S.



[Continuous infusion of ropivacaine has no effects on pyrolytic implant: a preliminary study in rats].  


The aim of the study is to analyse the effects of ropivacaïne on a pyrolytic implant in bone surgery. Ten rats were operated with a pyrolytic implant placed at the hip after femoral head resection: five cases with continuous infusion of ropivacaïne and five cases with continuous infusion of sterile water. Six days after, all the implants were analysed: weight, length, width, thickness and global design. This work showed that ropivacaïne can be use as continuous infusion with pyrolytic implant. Other studies in human surgery are necessary. PMID:22658585

Apard, T; Lancigu, R; Cronier, P



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.

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



Routine complete capsular closure during hip arthroscopy.  


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



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

NASA Astrophysics Data System (ADS)

Planned in-situ radiosensitization may improve the therapeutic ratio of image guided 125I prostate brachytherapy. Spacers used in permanent implants may be manufactured from a radiosensitizer-releasing polymer to deliver protracted localized sensitization of the prostate. Such devices will have a limited drug-loading capacity, and the drug release schedule that optimizes outcome, under such a constraint, is not known. This work determines the optimal elution schedules for 125I prostate brachytherapy. The interaction between brachytherapy dose distributions and drug distribution around drug eluting spacers is modeled using a linear-quadratic (LQ) model of cell kill. Clinical brachytherapy plans were used to calculate the biologic effective dose (BED) for planned radiation dose distributions while adding the spatial distributions of radiosensitizer while varying the temporal release schedule subject to a constraint on the drug capacity of the eluting spacers. Results: The greatest increase in BED is achieved by schedules with the greatest sensitization early in the implant. Making brachytherapy spacers from radiosensitizer eluting polymer transforms inert parts of the implant process into a means of enhancing the effect of the brachytherapy radiation. Such an approach may increase the therapeutic ratio of prostate brachytherapy or offer a means of locally boosting the radiation effect without increasing the radiation dose to surrounding tissues.

Cormack, Robert A.; Nguyen, Paul L.; D'Amico, Anthony V.; Sridhar, Sri; Makrigiorgos, Mike



Computer-Assisted Hip and Knee Arthroplasty. Navigation and Active Robotic Systems  

PubMed Central

Executive Summary Objective The Medical Advisory Secretariat undertook a review of the evidence on the effectiveness and cost-effectiveness of computer assisted hip and knee arthroplasty. The two computer assisted arthroplasty systems that are the topics of this review are (1) navigation and (2) robotic-assisted hip and knee arthroplasty. The Technology Computer-assisted arthroplasty consists of navigation and robotic systems. Surgical navigation is a visualization system that provides positional information about surgical tools or implants relative to a target bone on a computer display. Most of the navigation-assisted arthroplasty devices that are the subject of this review are licensed by Health Canada. Robotic systems are active robots that mill bone according to information from a computer-assisted navigation system. The robotic-assisted arthroplasty devices that are the subject of this review are not currently licensed by Health Canada. Review Strategy The Cochrane and International Network of Agencies for Health Technology Assessment databases did not identify any health technology assessments on navigation or robotic-assisted hip or knee arthroplasty. The MEDLINE and EMBASE databases were searched for articles published between January 1, 1996 and November 30, 2003. This search produced 367 studies, of which 9 met the inclusion criteria. Summary of Findings Navigation-Assisted Arthroplasty Five studies were identified that examined navigation-assisted arthroplasty. A Level 1 evidence study from Germany found a statistically significant difference in alignment and angular deviation between navigation-assisted and free-hand total knee arthroplasty in favour of navigation-assisted surgery. However, the endpoints in this study were short-term. To date, the long-term effects (need for revision, implant longevity, pain, functional performance) are unknown.(1) A Level 2 evidence short-term study found that navigation-assisted total knee arthroplasty was significantly better than a non-navigated procedure for one of five postoperative measured angles.(2) A Level 2 evidence short-term study found no statistically significant difference in the variation of the abduction angle between navigation-assisted and conventional total hip arthroplasty.(3) Level 3 evidence observational studies of navigation-assisted total knee arthroplasty and unicompartmental knee arthroplasty have been conducted. Two studies reported that “the follow-up of the navigated prostheses is currently too short to know if clinical outcome or survival rates are improved. Longer follow-up is required to determine the respective advantages and disadvantages of both techniques.”(4;5) Robotic-Assisted Arthroplasty Four studies were identified that examined robotic-assisted arthroplasty. A Level 1 evidence study revealed that there was no statistically significant difference between functional hip scores at 24 months post implantation between patients who underwent robotic-assisted primary hip arthroplasty and those that were treated with manual implantation.(6) Robotic-assisted arthroplasty had advantages in terms of preoperative planning and the accuracy of the intraoperative procedure.(6) Patients who underwent robotic-assisted hip arthroplasty had a higher dislocation rate and more revisions.(6) Robotic-assisted arthroplasty may prove effective with certain prostheses (e.g., anatomic) because their use may result in less muscle detachment.(6) An observational study (Level 3 evidence) found that the incidence of severe embolic events during hip relocation was lower with robotic arthroplasty than with manual surgery.(7) An observational study (Level 3 evidence) found that there was no significant difference in gait analyses of patients who underwent robotic-assisted total hip arthroplasty using robotic surgery compared to patients who were treated with conventional cementless total hip arthroplasty.(8) An observational study (Level 3 evidence) compared outcomes of total knee arthroplasty between patients undergoing robotic surgery and patients



No Difference in Gender-specific Hip Replacement Outcomes  

PubMed Central

Gender-specific total hip arthroplasty (THA) design has been recently debated with manufacturers launching gender-based designs. The purpose of this study was to investigate the survivorship and clinical outcomes of a large primary THA cohort specifically assessing differences between genders in clinical outcomes, implant survivorship, revisions as well as sizing and offset differences. We reviewed 3461 consecutive patients receiving 4114 primary THAs (1924 women, 1537 men) between 1980 and 2004 with a minimum of 2 years followup (mean, 11.33 ± 6.5 years). A subset of patients with complete implant data was reviewed for sizing and offset differences. Preoperative, latest, and change in clinical outcome scores as well as Kaplan–Meier analysis were performed. Men had higher raw clinical outcome scores preoperatively and postoperatively. Differences in change of clinical outcome scores were found only in the WOMAC pain score in favor of the female cohort (39.4 versus 36.1). Survivorship and revision rate were not significantly different. Men used larger stems with greater stem lengths, neck offset, and neck lengths. Current implant systems were sufficiently versatile to address the different size and offset needs of male and female patients. These data suggest there is no apparent need for a gender-designed THA system. Level of Evidence: Level II, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Kostamo, Timothy; Whittaker, John Paul; McCalden, Richard W.; MacDonald, Steven J.



Fretting corrosion accelerates crevice corrosion of modular hip tapers.  


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



Candida glabrata Prosthetic Hip Infection.  


We present a case of a 60-year-old Caucasian woman carrying a 2-year-old hip prosthesis infected by Candida glabrata dose-dependent susceptible to fluconazole and voriconazole. Resection arthroplasty was performed. Six weeks of caspofungin plus liposomal amphotericin combination therapy achieved joint sterilization and allowed a successfully reimplantation arthroplasty. In addition we review 9 cases of C. glabrata prosthetic joint infection described to date in the literature. PMID:23431513

Bartalesi, Filippo; Fallani, Stefania; Salomoni, Elena; Marcucci, Massimiliano; Meli, Massimo; Pecile, Patrizia; Cassetta, Maria Iris; Latella, Leonardo; Bartoloni, Alessandro; Novelli, Andrea



In vivo kinematic analysis of squatting after total hip arthroplasty  

Microsoft Academic Search

BackgroundThe in vivo kinematics of squatting after total hip arthroplasty is unclear. The purpose of the present study was to determine the range of motion of the hip joint during squatting after total hip arthroplasty.

Junichiro Koyanagi; Takashi Sakai; Takaharu Yamazaki; Tetsu Watanabe; Keisuke Akiyama; Nobuhiko Sugano; Hideki Yoshikawa; Kazuomi Sugamoto



Hip or knee replacement - after - what to ask your doctor  


... ask your doctor after hip or knee replacement; Hip replacement - after - what to ask your doctor; Knee replacement - after - what to ask your doctor ; Hip arthroplasty - after - what to ask your doctor ; Knee arthroplasty - ...


Hip arthroscopy: west of Scotland experience.  


Hip arthroscopy has evolved over the last decade. There had been an increase in the demand for hip arthroscopies from patients and their general practitioners due to available information and better diagnostic modalities like Magnetic resonance Arthrography. The senior author has performed 132 hip arthroscopies since 2010. This study was performed to reflect on our experience of hip arthroscopies to improve our practice. Data was collected prospectively between June 2011 and May 2013 for all patients undergoing Hip arthroscopy at Gartnavel General Hospital under the care of a specialist Hip surgeon. Demographics details, diagnosis of hip or groin pain, operative findings and surgical treatments performed were recorded for 49 patients. The mean age was 31 years (range 17-61). 57% patients were male and 43% female. 59% had right and 41% had left sided hip pathology. The diagnosis of hip pain following arthroscopy was Femoroacetabular Impingement and Labral tear in 67% patients, Femoroacetabular Impingement in 8%, isolated labral tear in 6%, Osteoarthritis in 16% and no intraarticular cause of hip pain was found in 2%. The site of Femoroacetabular impingement was anterior in 86% patients, anterolateral in 11% and lateral in 3% patients. The mean angle was 88 degrees of hip flexion for impingement (range 60-110). 75% patients had reduced anterior head and neck offset. The size of the labral tear was <5 mm in 11% patients, 5-10 mm in 8%, 10-15 mm in 23%, 15-20 mm in 37% and 20-25 mm in 20% patients. In our study cohort 67% patients had Femoroacetabular impingement and an associated labral tear which required treatment. 80% of patients had a tear of >10 mm in size. 16% of patients in our cohort had osteoarthritis changes which were not amenable to arthroscopic treatments. This reflective practice can help surgeons to improve patient selection for hip arthroscopy which can also result in improved outcomes following this procedure. PMID:24159101

Akhtar, Ma; Campton, L



Fluid extravasation during hip arthroscopy.  


The amount of fluid that may be lost into the soft tissues during hip arthroscopic surgery is unknown. We measured the volumes of irrigation fluid infused, operating time, fluid pressures and volumes of fluid recovered in 36 therapeutic hip arthroscopies. We excluded those where fluid was lost to the floor, leaving 28 patients. The majority were undergoing surgery for the treatment of femoroacetabular impingement. In 5 patients an intra-articular contrast medium was instilled, in order to establish the likely location of any extravasated fluid. The mean operating time was 68 minutes (31 to 120), and the mean infusion pressure was 46 mm Hg (30 to 70). The mean volume of infused fluid was 9677 ml (95% confidence interval (CI) 7715 to 11638) and the mean volume of fluid recovered was 8544 ml (95% CI 6715 to 10373). The mean fluid extravasation loss into the peri-articular tissues was 1132 ml (95% CI 808 ml to 1456 ml). There was a significant correlation between the volume of extravasated fluid and both the length of operation and the volume of infused fluid used. We had no adverse events in our series. During arthroscopic hip surgery more than a litre of irrigation fluid may be extravasated into the soft tissues. In order to reduce problems related to this we attempt to keep operating times low, and maintain intra-operative fluid pressures as low as possible. PMID:22117260

Stafford, Giles H; Malviya, Ajay; Villar, Richard N


Implant Chips  

NSDL National Science Digital Library

A group of eight people, including all members of one Florida family, had an implant chip, roughly the size of a grain of rice, injected under their skin on Friday, May 10. Manufactured by Applied Digital Solutions (ADS), the chips store a special identification number that enables the retrieval of personal and medical information. In the event of a medical emergency, a special handheld scanner activates the dormant digital implant, which provides identification data with which medical personnel can query ADS's database, the location of the patient's medical records. Alzheimer's patients seem to be the most promising market for this technology, even though other people, like the Florida family, hope to benefit from it as well. Another product that ADS offers is called Digital Angel, a wearable global positioning system (GPS) device that, among other things, can track in real time the wearer's physical movements. In the future, ADS is planning to release a product that will utilize both of these technologies: an implanted GPS-enabled chip. Unlike VeriChip, though, the GPS-enabled implant would require Food and Drug Administration (FDA) approval, meaning the US market won't see its introduction until after FDA testing. Many organizations, ranging from privacy advocates to religious groups, have already denounced VeriChip and its eventually successors, associated them with "Big Brother" and the biblical "Mark of the Beast."To read about the eight people that received their implants, look at the first and second sites, articles from the Los Angeles Times and Miami Herald respectively. For a non-US perspective, view the news story posted by the British Broadcasting Company (BBC). The fourth site, an extensive analysis of the subject from ABC News, should give readers a broader understanding of implanted chips and their potential uses. Two sites from ADS are next -- VeriChip's product pages and the press release that details a FDA's decision regarding VeriChip in April, 2002. Finally, the last two sites give more information on Digital Angel and a sample of GPS technology already in use.

Schroeder, Ted.



High complication rate in reconstruction of Paprosky type IIIa acetabular defects using an oblong implant with modular side plates and a hook.  


We report the results of 62 hips in 62 patients (17 males, 45 females) with mean age of 62.4 years (37 to 81), who underwent revision of the acetabular component of a total hip replacement due to aseptic loosening between May 2003 and November 2007. All hips had a Paprosky type IIIa acetabular defect. Acetabular revision was undertaken using a Procotyl E cementless oblong implant with modular side plates and a hook combined with impaction allografting. At a mean follow-up of 60.5 months (36 to 94) with no patients lost to follow-up and one died due to unrelated illness, the complication rate was 38.7%. Complications included aseptic loosening (19 hips), deep infection (3 hips), broken hook and side plate (one hip) and a femoral nerve palsy (one hip). Further revision of the acetabular component was required in 18 hips (29.0%) and a further four hips (6.4%) are currently loose and awaiting revision. We observed unacceptably high rates of complication and failure in our group of patients and cannot recommend this implant or technique. PMID:22161919

Babis, G C; Sakellariou, V I; Chatziantoniou, A N; Soucacos, P N; Megas, P



MR imaging of hip infection and inflammation.  


Inflammation of the hip may be due to infectious and noninfectious causes. Furthermore, involvement is categorized based on the origin and spread to adjacent structures involving the soft tissues, the joint, and underlying bone to refine the differential diagnosis. Magnetic resonance (MR) imaging is highly effective in establishing the presence and underlying cause of inflammatory and degenerative arthropathies. This article discusses the use of MR imaging for evaluation of various inflammatory conditions of the hip, both infectious and noninfectious. The number of hip prostheses is increasing, and inflammatory conditions involving the postoperative hip is also detailed separately. PMID:23168187

Maj, Luke; Gombar, Yuliya; Morrison, William B



Supports used for positioning of patients in hip arthroplasty: is there an infection risk?  

PubMed Central

INTRODUCTION Infection after joint arthroplasty is a disastrous complication. Implants used in hip arthroplasty increase the risk of infection from organisms of low pathogenicity. Potential reservoirs, that have not been assessed as yet, are the supports used for patient positioning in hip arthroplasty. The purpose of this study was to assess these supports for presence of bacterial pathogens. SUBJECTS AND METHODS We studied 40 supports used in 20 hip arthroplasty procedures. Tryptone soya agar plates were used to sample these supports. All agar plates were incubated at 37°C for 48 h. RESULTS Of the 20 anterior supports, 17 (85%) showed bacterial colonisation; of the 20 posterior supports, 10 (50%) had bacterial colonisation. Fourteen (52%) supports were contaminated with one organism, 9 (33%) with two organisms, three (11%) with three organisms and one (4%) with four organisms. Coagulase-negative staphylococci were the most common isolated organisms (61%) followed by coryneforms (10%) and bacilli (10%). Anterior supports had two times more colony forming units compared to the posterior supports. CONCLUSIONS This study showed contamination of supports used for positioning patients during hip arthroplasty. It reflects poor cleaning practice and certainly raises the possibility that a high bacterial load on these supports may contribute to higher infection rates in hip arthroplasties. The study raises concerns related to contamination of supports, as there is a potential for cross-infection, wound problems, and deep sepsis around implants which could be disastrous. While colonisation does not equate with infection, we suggest thorough cleaning of the supports before and after every surgical procedure.

Ahmad, Riaz; Tham, Ji; Naqvi, Syed Ghufran Ali; Butt, Umer; Dixon, John



Unique failure mechanism of a femoral component after revision total hip arthroplasty.  


As the prevalence of revision total hip arthroplasty increases, the mechanisms of failure of these revisions have become better delineated. Several studies have indicated infection, instability, and aseptic loosening to be the more common mechanisms of failure in revision surgery. However, with increasing numbers of revisions performed, unique mechanisms of failure are being seen, likely related to the implants that are used in the revision setting. Revision implants offer certain advantages over primary implants with the use of modular components. The revision implants allow the surgeon to increase offset and leg length with modular femoral bodies and necks. However, these modular junctions represent additional areas for implant failure. These new methods of failure associated with modular implants are slowly presenting as the use of these implants continues to increase. The authors recently encountered a mechanism of failure that, to their knowledge, has not been described in the literature. They report a 57-year-old man with dissociation of the proximal body from the diaphyseal component of a Wright Medical Link (Memphis, Tennessee) stem prosthesis. The patient presented with an audible click on physical examination, and radiographs confirmed dissociation of the proximal body. The intraoperative findings, treatment method, and proposed mechanisms for this type of failure are presented, as well as insight into potential ways to avoid this type of failure. PMID:24093712

Martin, J Ryan; Trousdale, Robert T



Bonding capacity in bone of HIP-processed HA-coated titanium: mechanical and histological investigations.  


The main problems using plasma-sprayed hydroxyapatite (HA) as a coating material on metallic implants are its porosity, low fatigue strength, and weak adherence to the metallic substrate. To overcome these problems a new technique using hot isostatic pressing (HIP) has been developed for producing HA-coated titanium (Ti) implants. Specimens produced at a maximum temperature of 850 degrees C and a maximum pressure of 720 bar displayed a dense, glassy, 25-microns thick coating with small amounts of porosity and a mean surface roughness of 0.7 microns, as compared with 1.6 microns for sandblasted Ti. Twenty conical HA-coated (720 and 100 bar pressure) and 10 noncoated Ti implants were inserted through the cortex of the lower margin of the mandibles of sheep and allowed to heal for 60 days. Push-out tests for implants processed at 720 bar pressure showed substantially higher bone/implant bonding values than for sandblasted Ti implants. Histological studies indicated a direct contact and probably chemical bonding between bone tissue and the HA coatings. The area of contact was almost 3 times as large as for the Ti implants. The adherence of the 100-bar coating to the Ti surface was inferior to the 720-bar coating, as shown by the loosening of the coatings in several areas. PMID:8582913

Wie, H; Herø, H; Solheim, T; Kleven, E; Rørvik, A M; Haanaes, H R



21 CFR 888.3380 - Hip joint femoral (hemi-hip) trunnion-bearing metal/polyacetal cemented prosthesis.  

Code of Federal Regulations, 2013 CFR

...joint femoral (hemi-hip) trunnion-bearing metal/polyacetal cemented prosthesis...joint femoral (hemi-hip) trunnion-bearing metal/polyacetal cemented prosthesis...joint femoral (hemi-hip) trunnion-bearing metal/ polyacetal cemented...



Penile Implants  

Microsoft Academic Search

Effective penile implants were introduced in the early 1970s and have provided a predictable and reliable treatment of erectile\\u000a dysfunction. They can be placed in almost all circumstances in which more conservative treatments have been ineffective or\\u000a are contraindicated. Manufacturers of these devices have improved their functioning and durability, and repair rates are low\\u000a when compared with other mechanical products.

Steven K. Wilson; John J. Mulcahy


Early prosthetic joint infections treated with debridement and implant retention  

PubMed Central

Background and purpose Debridement and retention of the prosthesis is often attempted to treat early prosthetic joint infection (PJI). However, previous studies have found inconsistent results, with success rates ranging from 21% to 100%, and little has been written in the literature about hip function. We have therefore analyzed the clinical and functional outcome of early PJIs treated with this procedure. Patients and methods 38 patients with early PJI after primary hip arthroplasty who were treated with debridement and retention of the implant between 1998 and 2005 were studied prospectively, with a median follow-up time of 4 (0.8–10) years. Early infection was defined as that which occurred within 4 weeks of index arthroplasty. The primary outcome measure was infection control. Functional outcome was assessed with the Harris hip score. Results 27 of 38 patients were successfully treated, with no signs of infection or continued antibiotic treatment at the latest follow-up. Median Harris hip score was 86 (47–100) points. In 9 of the 11 patients for whom treatment failed, infection was successfully treated with 1-stage or 2-stage reimplantation or resection. Intraoperative cultures were positive in 36 hips, and the most frequently isolated organisms were Staphylococcus aureus and coagulase-negative staphylococci (CoNS). 15 infections were polymicrobial, and only 8 of them were successfully treated with debridement and retention of the implant. Interpretation Our data suggest that debridement and retention of the prosthesis is a reasonable treatment option in early PJI after primary hip arthroplasty, with satisfactory functional results.



Altered palmitoylation and neuropathological deficits in mice lacking HIP14  

PubMed Central

Huntingtin interacting protein 14 (HIP14, ZDHHC17) is a huntingtin (HTT) interacting protein with palmitoyl transferase activity. In order to interrogate the function of Hip14, we generated mice with disruption in their Hip14 gene. Hip14?/? mice displayed behavioral, biochemical and neuropathological defects that are reminiscent of Huntington disease (HD). Palmitoylation of other HIP14 substrates, but not Htt, was reduced in the Hip14?/? mice. Hip14 is dysfunctional in the presence of mutant htt in the YAC128 mouse model of HD, suggesting that altered palmitoylation mediated by HIP14 may contribute to HD.

Singaraja, Roshni R.; Huang, Kun; Sanders, Shaun S.; Milnerwood, Austen J.; Hines, Rochelle; Lerch, Jason P.; Franciosi, Sonia; Drisdel, Renaldo C.; Vaid, Kuljeet; Young, Fiona B.; Doty, Crystal; Wan, Junmei; Bissada, Nagat; Henkelman, R. Mark; Green, William N.; Davis, Nicholas G.; Raymond, Lynn A.; Hayden, Michael R.



Osteogenic phenomena across endosteal bone-implant spaces with porous surfaced intramedullary implants.  


Porous surfaced femoral components of hip prostheses stabilized by tissue ingrowth are often situated a certain distance away from the endosteal cortex in the diaphysis. The purpose of this study was to examine the significance of this space between an implant and the cortex on bone growth into the porous surface of the implant. Intramedullary rods of different diameters with porous surface regions made of powder metal were inserted into the femurs of adult beagles. The rods had outside diameters of 2.5, 3.2, 4.5, and 5.5 millimeters; this variation produced endosteal bone-implant surface spaces ranging from 0 to 4 millimeters. The animals were sacrificed at 4, 8, 12, and 16 weeks. Histological sections revealed that by 12 weeks the implants became generally surrounded by a thin shell of spongy bone which was joined to the endosteal cortex by bony trabeculae. This feature was most prominent for implants which were approximately 2 millimeters or less from the endosteum. Denser, more haversian-like bone developed up to and within those areas of implants which were in contact with the cortex. The development of this intramedullary type of bone could significantly contribute to the fixation strength of clinical porous surfaced prostheses whose stems do not completely fill the medulla. PMID:7246092

Bobyn, J D; Pilliar, R M; Cameron, H U; Weatherly, G C



2008 Otto Aufranc Award: component design and technique affect cement penetration in hip resurfacing.  


Either excessive or insufficient cement penetration within the femoral head after hip resurfacing influences the risk of femoral failures. However, the factors controlling cement penetration are not yet fully understood. We determined the effect of femoral component design and cementation technique on cement penetration. Six retrieved femoral heads were resurfaced for each implant (BHR, ASR, Conserve Plus, DuROM, ReCAP) using the manufacturers' recommendations for implantation. In addition, the BHR was implanted using the Conserve Plus high-viscosity cementation technique, "BHR/hvt," and vice versa for the Conserve, "Conserve/lvt." The average cement penetration was highest with BHR (65.62% +/- 15.16%) compared with ASR (12.25% +/- 5.12%), Conserve Plus(R) (19.43% +/- 5.28%), DuROM (17.73% +/- 3.96%), and ReCAP (26.09% +/- 5.20%). Cement penetration in BHR/hvt remained higher than all other implants equaling 36.7% +/- 6.6%. Greater femoral component design clearance correlated with cement mantle thickness. Femoral component design in hip resurfacing plays a major role in cement penetration. PMID:18923883

Beaulé, Paul E; Matar, Wadih Y; Poitras, Philippe; Smit, Kevin; May, Olivier



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)



Internal Transcribed Spacer (ITS)-PCR Identification of MRSA.  


Polymerase chain reaction (PCR) analysis of the 16S-23S rRNA gene internal transcribed spacer (ITS) followed by microchip gel electrophoresis was useful for identification of staphylococci and for strain delineation of Staphylococcus aureus. In the study presented in this chapter, 74 ITS patterns were demonstrated among 1,188 isolated colonies of S. aureus: 55 patterns for methicillin-susceptible S. aureus (MSSA), 4 patterns for methicillin-resistant S. aureus (MRSA), and 15 patterns for both MSSA and MRSA, highlighting the inability of ITS pattern analysis to differentiate the MSSA and MRSA strains. To overcome this problem, simultaneous PCR amplification of the ITS region and mecA gene was applied to isolated colonies of staphylococcus species and positive-testing blood culture bottles. PMID:24085691

Fujita, Shin-Ichi



Microfluidic flows in metallic microchannels fabricated by the spacer method  

NASA Astrophysics Data System (ADS)

Straight and bent copper microchannels are fabricated by the spacer method and their microfluidic flow characteristics are investigated. The effect of the surface roughness of the microchannel walls, which can be controlled by selecting the starting copper powder size, is focused on. The rough surface of a thin straight microchannel (with an arithmetic surface roughness of 4.3 µm and a diameter of 180 µm) caused a higher pressure gradient than other straight microchannels. The pressure gradient for the rough and thin microchannel exceeded the theoretical value for laminar flow at a lower Reynolds number than that reported for a cylindrical pipe with larger dimensions. It is concluded that the large surface roughness relative to the microchannel diameter leads to the early transition from laminar to turbulent flow. Experimental results for bent microchannels also indicate that the large surface roughness at a sharp bend causes significant flow separation.

Hakamada, Masataka; Asao, Yuuki; Saito, Naobumi; Mabuchi, Mamoru



Method of forming a spacer for field emission flat panel displays  

Microsoft Academic Search

Spacers are disclosed for applications such as field emission flat panel displays and vacuum microelectronics, and which involves the application of aerogel\\/xerogel technology to the formation of the spacer. In a preferred approach the method uses a mold and mold release agent wherein the gel precursor is a liquid which can be applied to the mold filling holes which expose

A. F. Bernhardt; R. J. Contolini



Method of forming a spacer for field emission flat panel displays  

Microsoft Academic Search

Spacers for applications such as field emission flat panel displays and vacuum microelectronics, and which involves the application of aerogel\\/xerogel technology to the formation of the spacer. In a preferred approach the method uses a mold and mold release agent wherein the gel precursor is a liquid which can be applied to the mold filling holes which expose the substrate

Anthony F. Bernhardt; Robert J. Contolini



Single electron transistor with P-type sidewall spacer gates.  


A single-electron transistor (SET) is one of the promising solutions to overcome the scaling limit of the Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET). Up to now, various kinds of SETs are being proposed and SETs with a dual gate (DG) structure using an electrical potential barrier have been demonstrated for room temperature operation. To operate DG-SETs, however, extra bias of side gates is necessary. It causes new problems that the electrode for side gates and the extra bias for electrical barrier increase the complexity in circuit design and operation power consumption, respectively. For the reason, a new mechanism using work function (WF) difference is applied to operate a SET at room temperature by three electrodes. Its structure consists of an undoped active region, a control gate, n-doped source/drain electrodes, and metal/silicide or p-type silicon side gates, and a SET with metal/silicide gates or p-type silicon gates forms tunnel barriers induced by work function between an undoped channel and grounded side gates. Via simulation, the effectiveness of the new mechanism is confirmed through various silicide materials that have different WF values. Furthermore, by considering the realistic conditions of the fabrication process, SET with p-type sidewall spacer gates was designed, and its brief fabrication process was introduced. The characteristics of its electrical barrier and the controllability of its control gate were also confirmed via simulation. Finally, a single-hole transistor with n-type sidewall spacer gates was designed. PMID:22121580

Lee, Jung Han; Li, Dong Hua; Lee, Joung-Eob; Kang, Kwon-Chil; Kim, Kyungwan; Park, Byung-Gook



In Vitro Fatigue Failure of Cemented Acetabular Replacements: A Hip Simulator Study  

PubMed Central

Although hip simulators for in vitro wear testing of prosthetic materials used in total hip arthroplasty (THA) have been available for a number of years, similar equipment has yet to appear for endurance testing of fixation in cemented THA, despite considerable evidence of late aseptic loosening as one of the most significant failure mechanisms in this type of replacements. An in vitro study of fatigue behavior in cemented acetabular replacements has been carried out, utilizing a newly developed hip simulator. The machine was designed to simulate the direction and the magnitude of the hip contact force under typical physiological loading conditions, including normal walking and stair climbing, as reported by Bergmann et al. (2001, Hip 98, Freie Universitaet, Berlin). A 3D finite element analysis has been carried out to validate the function of the hip simulator and to evaluate the effects of boundary conditions and geometry of the specimen on the stress distribution in the cement mantle. Bovine pelvic bones were implanted with a Charnley cup, using standard manual cementing techniques. Experiments were carried out under normal walking and descending stairs loading conditions with selected load levels from a body weight of 75-125 kg. Periodically, the samples were removed from the test rigs to allow CT scanning for the purpose of monitoring damage development in the cement fixation. The hip simulator was found to be satisfactory in reproducing the hip contact force during normal walking and stair climbing, as reported by Bergmann et al. Finite element analysis shows that the stress distributions in the cement mantle and at the bone-cement interface are largely unaffected by the geometry and the boundary conditions of the model. Three samples were tested up to 17 × 106 cycles and sectioned post-testing for microscopic studies. Debonding at the bone-cement interface of various degrees in the posterior-superior quadrant was revealed in these samples, and the location of the failures corresponds to the highest stressed region from the finite-element analysis. Preliminary experimental results from a newly developed hip simulator seem to suggest that debonding at the bone-cement interface is the main failure mechanism in cemented acetabular replacements, and descending stairs seem to be more detrimental than normal walking or ascending stairs with regard to fatigue integrity of cement fixation.

Zant, N. P.; Heaton-Adegbile, P.; Hussell, G. J.; Tong, J.



Electrochemical Evaluation of Nanocrystalline Diamond Thin Films on Ti6Al4V Implant Alloy  

Microsoft Academic Search

Some 186,000 hip replacement surgeries are peformed every year in the United States alone. About 10surgeries are revision operations to replace an implant that has most likely failed through mechanical-electrochemical interactions resulting in implant wear. The ability to enhance the resistance to such mechanical-electrochemical interaction and thereby reduce wear could result in significantly increased device lifespan. Nanocrystalline diamond (NCD) thin

Marc Fries; Ramakrishna Venugopalan; Yogesh Vohra



Metallic wear debris in dual modular hip arthroplasty.  


Two cementless hip arthroplasty models with a modular neck made titanium alloy were submitted to cyclical loading in air, in physiological solution, and in a solution for accelerated corrosion tests in order to study the damage process of modular couplings. Thereafter, on one of the two models a series of tests were conducted in order to evaluate the quality of debris produced by the couplings. The parameters of testing adopted allow us to estimate the production of metallic debris observable in vivo with this type of prosthetic stem. The results show that the couplings of modular prostheses may be the source of metallic debris. The amount of debris produced depends on the geometry of the coupling and of the entire implant. Good planning and realization of the couplings, however, reduce the phenomenon that is negligible as compared to other potential sources of debris such as the surface of the stem or of the prosthetic head. PMID:9494240

Baleani, M; Viceconti, M; Walchholz, K; Toni, A


Synthesis and evaluation of new spacers for use as dsDNA end-caps.  


A series of aliphatic and aromatic spacer molecules designed to cap the ends of DNA duplexes have been synthesized. The spacers were converted into dimethoxytrityl-protected phosphoramidites as synthons for oligonucleotides synthesis. The effect of the spacers on the stability of short DNA duplexes was assessed by melting temperature studies. End-caps containing amide groups were found to be less stabilizing than the hexaethylene glycol spacer. End-caps containing either a terthiophene or a naphthalene tetracarboxylic acid diimide were found to be significantly more stabilizing. The former showed a preference for stacking above an A*T base pair. Spacers containing only methylene (-CH(2)-) and amide (-CONH-) groups interact weakly with DNA and consequently may be optimal for applications that require minimal influence on DNA structure but require a way to hold the ends of double-stranded DNA together. PMID:20715857

Ng, Pei-Sze; Laing, Brian M; Balasundarum, Ganesan; Pingle, Maneesh; Friedman, Alan; Bergstrom, Donald E



Synthesis and evaluation of new spacers for use as dsDNA endcaps  

PubMed Central

A series of aliphatic and aromatic spacer molecules designed to cap the ends of DNA duplexes have been synthesized. The spacers were converted into dimethoxytrityl protected phosphoramidites as synthons for oligonucleotides synthesis. The effect of the spacers on the stability of short DNA duplexes was assessed by melting temperature studies. Endcaps containing amide groups were found to be less stabilizing than the hexaethylene glycol spacer. Endcaps containing either a terthiophene or a naphthalene tetracarboxylic acid dimide were found to be significantly more stabilizing. The former showed a preference for stacking above an A•T base pair. Spacers containing only methylene (-CH2-) and amide (-CONH-) groups interact weakly with DNA and consequently may be optimal for applications that require minimal influence on DNA structure but require a way to hold the ends of double-stranded DNA together.

Ng, Pei-Sze; Laing, Brian M.; Balasundarum, Ganesan; Pingle, Maneesh; Friedman, Alan; Bergstrom, Donald E.



Low temperature plasma-enhanced ALD enables cost-effective spacer defined double patterning (SDDP)  

NASA Astrophysics Data System (ADS)

The inherent advantages of the Plasma-Enhanced Atomic Layer Deposition (PEALD) technology?excellent conformality and within wafer uniformity, no loading effect?overcome the limitations in this domain of the standard PECVD technique for spacer deposition. The low temperature process capability of PEALD silicon oxide enables direct spacer deposition on photoresist, thus suppressing the need of a patterned template hardmask to design the spacers. By decreasing the number of deposition and patterning steps, this so-called Direct Spacer Defined Double Patterning (DSDDP) integration reduces cost and complexity of the conventional SDDP approach. A successful integration is reported for 32 nm half-pitch polysilicon lines. The performances are promising, especially from the lines, which result from the PEALD spacers: Critical Dimension Uniformity (CDU) of 1.3 nm and Line Width Roughness (LWR) of 2.0 nm.

Beynet, Julien; Wong, Patrick; Miller, Andy; Locorotondo, Sabrina; Vangoidsenhoven, Diziana; Yoon, Tae-Ho; Demand, Marc; Park, Hyung-Sang; Vandeweyer, Tom; Sprey, Hessel; Yoo, Yong-Min; Maenhoudt, Mireille



Osteoporotic Hip Fractures: The Burden of Fixation Failure  

PubMed Central

Osteoporotic hip fractures are a major cause of morbidity and mortality in the elderly. Furthermore, reduced implant anchorage in osteoporotic bone predisposes towards fixation failure and with an ageing population, even low failure rates represent a significant challenge to healthcare systems. Fixation failure in fragility fractures of the hip ranges from 5% in peritrochanteric fractures through to 15% and 41% in undisplaced and displaced fractures of the femoral neck, respectively. Our findings, in general, support the view that failed internal fixation of these fragility fractures carries a poor prognosis: it leads to a twofold increase in the length of hospital stay and a doubling of healthcare costs. Patients are more likely to suffer a downgrade in their residential status upon discharge with a consequent increase in social dependency. Furthermore, the marked disability and reduction in quality of life evident before salvage procedures may persist at long-term followup. The risk, of course, for the elderly patient with a prolonged period of decreased functioning is that the disability becomes permanent. Despite this, however, no clear link between revision surgery and an increase in mortality has been demonstrated in the literature.

Broderick, J. M.; Bruce-Brand, R.; Stanley, E.; Mulhall, K. J.



Functional acetabular component position with supine total hip replacement.  


Orientation of the acetabular component influences wear, range of movement and the incidence of dislocation after total hip replacement (THR). During surgery, such orientation is often referenced to the anterior pelvic plane (APP), but APP inclination relative to the coronal plane (pelvic tilt) varies substantially between individuals. In contrast, the change in pelvic tilt from supine to standing (dPT) is small for nearly all individuals. Therefore, in THR performed with the patient supine and the patient's coronal plane parallel to the operating table, we propose that freehand placement of the acetabular component placement is reliable and reflects standing (functional) cup position. We examined this hypothesis in 56 hips in 56 patients (19 men) with a mean age of 61 years (29 to 80) using three-dimensional CT pelvic reconstructions and standing lateral pelvic radiographs. We found a low variability of acetabular component placement, with 46 implants (82%) placed within a combined range of 30° to 50° inclination and 5° to 25° anteversion. Changing from the supine to the standing position (analysed in 47 patients) was associated with an anteversion change < 10° in 45 patients (96%). dPT was < 10° in 41 patients (87%). In conclusion, supine THR appears to provide reliable freehand acetabular component placement. In most patients a small reclination of the pelvis going from supine to standing causes a small increase in anteversion of the acetabular component. Cite this article: Bone Joint J 2013;95-B:1326-31. PMID:24078527

Eilander, W; Harris, S J; Henkus, H E; Cobb, J P; Hogervorst, T



Bone grafting and two-stage revision total hip arthroplasty.  


Periprosthetic deep infection in combination with substantial bone loss is one of the most challenging situations in revision hip surgery. We believe the effective management of these patients requires infection control as well as bone reconstruction. A review of our previously published studies on antibiotic loaded bone allografts is presented in this paper. These investigations provided us with information on the use of bone allografts in combination with antibiotics in cases of previous infection. Our protocol is based on removal of implants, meticulous debridement, parenteral antibiotic therapy and a second-stage reconstruction with vancomycin-supplemented bone allografts to treat an infected hip arthroplasty. We observed that vancomycin does not affect bone allograft incorporation at concentrations that are 300 times higher than the minimum inhibitory concentration for Staphylococcus aureus and Staphylococcus epidermidis. We also obtained adequate pharmacokinetics using these composites, with high local levels without renal impairment. This method has the capacity of acetabular and femoral bone stock restoration, with sound fixation and without increasing the rate of reinfection. PMID:22956371

Buttaro, Martin A


An implantable RF-powered dual channel stimulator.  


An implantable RF-powered dual channel stimulator was designed for hip stabilization. The approach included: small size, low power consumption, external powering, adjustable output current stimulus, dual channel operation an hermetic sealed electronic packaging. Thick film hybrid circuit techniques were used. The circuit and RF powering scheme were designed for low power operation with compromise to allow for linear and lateral displacements between the transmitting and receiving antenna. The output stimuli are biphasic negative going current pulses of 175 microseconds duration and 0-5 mA amplitude. Hermeticity is provided by enclosure of the electronics in a flat pack and subsequent epoxy coating of the implant assembly. PMID:7295933

Poon, C W; Ko, W H; Peckham, P H; McNeal, D R; Su, N



Preliminary analysis and design optimization of the short spacer truss of Space Station Freedom  

NASA Astrophysics Data System (ADS)

The analysis, dynamic simulation, and design optimization of the short spacer truss of the Space Station Freedom are presented in this report. The short spacer truss will be positioned between the integrated equipment assembly (IEA) and another truss, called the long spacer truss, in the Space Station Freedom. During its launch in the Space Shuttle, the truss will be subjected to considerable in-span distributed inertia loads due to shuttle accelerations. The short spacer truss, therefore, has been modeled as a space frame to account for flexural response. Several parameters have been assumed, since the design specifications are in the process of development; hence the results presented should be considered preliminary. However, the automated analysis and design capabilities that have been developed can readily be used to generate an optimum design of the short spacer truss once the actual specifications have been determined. This report includes static and dynamic analyses of the short spacer truss, which have been obtained with the linear elastic code LE-HOST (in these analyses, LE-HOST data files have been automated to facilitate their future use for different design specifications of the short spacer truss); the dynamic animation of the short spacer truss, which has been carried out by using the results of the dynamic analysis and a post-processing feature of the modeling code PATRAN; and the optimum-weight design of the spacer truss, which was obtained under prescribed stress, displacement, and frequency constraints by using the design code COMETBOARDS. Examination of the analysis and design results revealed that the design could be improved if the configuration of the short spacer truss were modified to a certain extent. A modified configuration, which may simplify fabrication, has been suggested. The performance of this configuration has been evaluated and was found to be satisfactory under both static and dynamic conditions.

Gendy, A. S.; Patnaik, S. N.; Hopkins, D. A.; Berke, L.



Treatment of Crowe IV high hip dysplasia with total hip replacement using the Exeter stem and shortening derotational subtrochanteric osteotomy.  


We evaluated all cases involving the combined use of a subtrochanteric derotational femoral shortening osteotomy with a cemented Exeter stem performed at our institution. With severe developmental dysplasia of the hip an osteotomy is often necessary to achieve shortening and derotation of the proximal femur. Reduction can be maintained with a 3.5 mm compression plate while the implant is cemented into place. Such a plate was used to stabilise the osteotomy in all cases. Intramedullary autograft helps to prevent cement interposition at the osteotomy site and promotes healing. There were 15 female patients (18 hips) with a mean age of 51 years (33 to 75) who had a Crowe IV dysplasia of the hip and were followed up for a mean of 114 months (52 to 168). None was lost to follow-up. All clinical scores were collected prospectively. The Charnley modification of the Merle D'Aubigné-Postel scores for pain, function and range of movement showed a statistically significant improvement from a mean of 2.4 (1 to 4), 2.3 (1 to 4), 3.4 (1 to 6) to 5.2 (3 to 6), 4.4 (3 to 6), 5.2 (4 to 6), respectively. Three acetabular revisions were required for aseptic loosening; one required femoral revision for access. One osteotomy failed to unite at 14 months and was revised successfully. No other case required a femoral revision. No postoperative sciatic nerve palsy was observed. Cemented Exeter femoral components perform well in the treatment of Crowe IV dysplasia with this procedure. PMID:21196540

Charity, J A F; Tsiridis, E; Sheeraz, A; Howell, J R; Hubble, M J W; Timperley, A J; Gie, G A



The Interspinous Spacer: A Clinicoanatomical Investigation Using Plastination  

PubMed Central

Purpose. The relatively new and less-invasive therapeutic alternative “interspinous process decompression device (IPD)” is expected to result in improved symptoms of neurogenic intermittent claudication (NIC) caused by lumbar spinal stenosis. The aim of the study was to analyze IPD position particularly regarding damage originating from surgical implantation. Methods. Anatomic assessments were performed on a fresh human cadaver. For the anatomic examination, the lumbar spine was plastinated after implantation of the IPDs. After radiographic control, serial 4 mm thick sections of the block plastinate were cut in the sagittal (L1–L3) and horizontal (L3–L5) planes. The macroanatomical positioning of the implants was then analyzed. The insertion procedure caused only little injury to osteoligamentous or muscular structures. The supraspinous ligament was completely intact, and the interspinous ligaments were not torn as was initially presupposed. No osseous changes at the spinal processes were apparent. Contact of the IPD with the spinous processes was visible, so that sufficient biomechanical limitation of the spinal extension seems likely. Conclusions. Minimally invasive IPD implantation with accurate positioning in the anterior portion of the interspinous place is possible without severe surgical trauma.

Kaulhausen, Thomas; Zarghooni, Kourosh; Stein, Gregor; Knifka, Jutta; Eysel, Peer; Koebke, Juergen; Sobottke, Rolf



Assessment of modified gold surfaced titanium implants on skeletal fixation  

PubMed Central

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.

Zainali, Kasra; Danscher, Gorm; Jakobsen, Thomas; Baas, Jorgen; M?ller, Per; Bechtold, Joan E.; Soballe, Kjeld



Total hip replacement with an entirely hydroxyapatite-coated prosthesis: 5 years' follow-up of 94 consecutive hips.  


The first 100 consecutive entirely hydroxyapatite (HA)-coated hip arthroplasties in 86 patients (mean age, 56.2 years [range, 32-7