Within the first two years after total hip arthroplasty implant-associated infection has become the second most common reason for a revision surgery. Two-stage implant exchange is frequently conducted using temporary spacers made of antibiotic-loaded cement in order to prevent a bacterial colonization on the spacer. Avoiding several disadvantages of cement spacers, a conventional hemi-endoprosthesis was equipped with a copper-containing implant coating for inhibition of bacterial biofilms. In the present paper details of this novel treatment concept are presented including a case report. PMID:22242097
Ellenrieder, Martin; Haenle, Maximilian; Lenz, Robert; Bader, Rainer; Mittelmeier, Wolfram
Antibiotic-impregnated hip cement spacers of various types and materials have been used in the treatment of periprosthetic hip infections. We developed a handmade spacer by using polymethylmethacrylate (PMMA) and/or ? -tricalcium phosphate ( ? -TCP). In this study, we retrospectively reviewed the surgical outcomes in 36 consecutive patients treated with 2-stage revision total hip arthroplasty by using our antibiotic-impregnated hip cement spacers. We aimed to analyze the infection control and reinfection rates after revision surgery. Moreover, we analyzed the possible predictors of postoperative reinfection. After exclusion of 1 patient who died immediately after the first-stage surgery, infection was controlled in 33 of the 36 hips (success rate, 91.7%). Two of these 33 hips underwent resection arthroplasty. Of the 36 hips that had been treated with the antibiotic-cement spacer, 31 hips (86.1%) were eligible for the second-stage prosthesis re-implantation. The 31 protocol hip joints of patients followed up for >6 months (mean, 48.6 months). Ten of these 31 hips (32.3%) became reinfected. No possible predictor examined differed significantly between the reinfection-positive and reinfection-negative groups. However, spacers consisting of PMMA cement alone were associated with the highest risk of reinfection. Therefore, ? -TCP-containing antibiotic-impregnated hip cement spacers might decrease the reinfection rate in patients undergoing re-implantation. PMID:24381509
Uchiyama, Katsufumi; Takahira, Naonobu; Fukushima, Kensuke; Moriya, Mitsutoshi; Yamamoto, Takeaki; Minegishi, Yojiro; Sakai, Rina; Itoman, Moritoshi; Takaso, Masashi
Antibiotic-impregnated hip cement spacers of various types and materials have been used in the treatment of periprosthetic hip infections. We developed a handmade spacer by using polymethylmethacrylate (PMMA) and/or ?-tricalcium phosphate (?-TCP). In this study, we retrospectively reviewed the surgical outcomes in 36 consecutive patients treated with 2-stage revision total hip arthroplasty by using our antibiotic-impregnated hip cement spacers. We aimed to analyze the infection control and reinfection rates after revision surgery. Moreover, we analyzed the possible predictors of postoperative reinfection. After exclusion of 1 patient who died immediately after the first-stage surgery, infection was controlled in 33 of the 36 hips (success rate, 91.7%). Two of these 33 hips underwent resection arthroplasty. Of the 36 hips that had been treated with the antibiotic-cement spacer, 31 hips (86.1%) were eligible for the second-stage prosthesis re-implantation. The 31 protocol hip joints of patients followed up for >6 months (mean, 48.6 months). Ten of these 31 hips (32.3%) became reinfected. No possible predictor examined differed significantly between the reinfection-positive and reinfection-negative groups. However, spacers consisting of PMMA cement alone were associated with the highest risk of reinfection. Therefore, ?-TCP-containing antibiotic-impregnated hip cement spacers might decrease the reinfection rate in patients undergoing re-implantation. PMID:24381509
Takahira, Naonobu; Moriya, Mitsutoshi; Yamamoto, Takeaki; Minegishi, Yojiro; Sakai, Rina; Itoman, Moritoshi; Takaso, Masashi
The common recommended treatment for infected total hip replacement is two-staged exchange including removal of all components. However, removal of well-fixed femoral stems can result in structural bone damage. We recently reported on an alternative treatment of partial two-stage exchange used in selected cases, in which a well-fixed femoral stem was left and only the acetabular component removed, the joint space was debrided thoroughly, an antibiotic-laden polymethylmethacrylate spacer was moulded using a bulb-type syringe and placed in the acetabulum, intravenous antibiotics were administered during the interval, and delayed re-implantation was performed. In 19 patients treated with this technique from January 2000 to January 2011, 89% were free of infection at a mean follow-up of four years (2 to 11). Since then, disposable silicone moulds have become available to fabricate spacers in separate femoral and head units. The head spacer mould, which incorporates various neck taper adapter options, greatly facilitates the technique of partial two-stage exchange. We report our early experience using disposable silicone head spacer moulds for partial two-stage exchange in seven patients with infected primary hip replacements. Cite this article: Bone Joint J 2014;96-B(11 Suppl A):66-9. PMID:25381411
Lombardi, A V; Berend, K R; Adams, J B
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
Infection is a devastating complication after total-hip arthroplasty. Between June 1991 and December 2001, 42 patients were treated at our center for chronically infected total-hip arthroplasty using a 2-stage articulating antibiotic hip spacer technique. Of the 27 patients available for review, 26 (94%) remain clinically free of infection at an average 76 months (range, 28-148 months) postoperatively. Twenty-two (81%) patients
Aaron A. Hofmann; Tyler D. Goldberg; Amie M. Tanner; Thomas M. Cook
Deep infection of a joint endoprosthesis constitutes a threat to the stability of the implant and joint function. It requires a comprehensive and interdisciplinary approach, involving the joint revision and removal of the bacterial biofilm from all tissues, the endoprosthesis must be often removed and bone stock infection treated. The paper presents the author's experience with the use of acrylic cement spacers, custom-made during the surgery and containing low dose of an antibiotic supplemented with 5% of a selected, targeted antibiotic for the infection of hip and knee endoprostheses. 33 two-stage revisions of knee and hip joints with the use of a spacer were performed. They involved 24 knee joints and 9 hip joints. The infections were mostly caused by staphylococci MRSA (18) and MSSA (8), and in some cases Enterococci (4), Salmonella (1), Pseudomonas (1) and Acinetobacter (1). The infection was successfully treated in 31 out of 33 cases (93.93%), including 8 patients with the hip infection and 23 patients with the knee infection. The endoprosthesis was reimplanted in 30 cases: for 7 hips and 23 knees, in 3 remaining cases the endoprosthesis was not reimplanted. Mechanical complications due to the spacer occurred in 4 cases: 3 dislocations and 1 fracture (hip spacer). The patients with hip spacers were ambulatory with a partial weight bearing of the operated extremity and those with knee spacers were also ambulatory with a partial weight bearing, but the extremity was initially protected by an orthosis. The spacer enables to maintain a limb function, and making it by hand allows the addition of the specific bacteria targeted antibiotic thus increasing the likelihood of the effective antibacterial treatment. PMID:23306284
Total hip arthroplasty is a widespread surgical approach for treating severe osteoarthritis of the human hip. Aseptic loosening of standard metallic hip implants due to stress shielding and bone loss has motivated the development of new materials for hip prostheses. Numerically, a three-dimensional finite element (FE) model that mimicked hip implants was used to compare a new hip stem to two commercially available implants. The hip implants simulated were a novel CF/PA12 carbon-fibre polyamide-based composite hip stem, the Exeter hip stem (Stryker, Mahwah, NJ, USA), and the Omnifit Eon (Stryker, Mahwah, NJ, USA). A virtual axial load of 3 kN was applied to the FE model. Strain and stress distributions were computed. Experimentally, the three hip stems had their distal portions rigidly mounted and had strain gauges placed along the surface at 3 medial and 3 lateral locations. Axial loads of 3 kN were applied. Measurements of axial stiffness and strain were taken and compared to FE analysis. The overall linear correlation between FE model versus experimental strains showed reasonable results for the lines-of-best-fit for the Composite (Pearson R(2)=0.69, slope=0.82), Exeter (Pearson R(2)=0.78, slope=0.59), and Omnifit (Pearson R(2)=0.66, slope=0.45), with some divergence for the most distal strain locations. From FE analysis, the von Mises stress range for the Composite stem was much lower than that in the Omnifit and Exeter implants by 200% and 45%, respectively. The preliminary experiments showed that the Composite stem stiffness (1982 N/mm) was lower than the metallic hip stem stiffnesses (Exeter, 2460 N/mm; Omnifit, 2543 N/mm). This is the first assessment of stress, strain, and stiffness of the CF/PA12 carbon-fibre hip stem compared to standard commercially-available devices. PMID:20952241
Bougherara, Habiba; Zdero, Rad; Dubov, Anton; Shah, Suraj; Khurshid, Shaheen; Schemitsch, Emil H
Bone-saving hip arthroplasty using metaphyseal stems is gaining importance because the number of young patients is on the increase and hip resurfacing is not always indicated. This article outlines the recent developments in short stem hip replacement following the concept of conservative hip implants. The individual decision for use of a particular type of implant remains crucial because a stem
Wolfram H. Kluge
Hip implant is an orthopedic procedure which the hip joint is replaced by prosthetic or artificial implant in order to replace arthritic or dysfunctional joint surface. The process is also known as hip arthroplasty. However, the metal-on-metal hips articulation suffers from friction due to the moving metal surface thus, shortening the surviving of the joint. A micro pits formation is
Nor Liyana Safura Hashim; Azli Yahya; Mohammed Rafiq Abdul Kadir; Syahrullail Samion; Nazriah Mahmud
The authors report a rare case of an 75-year-old female patient who had had a Mueller cemented total hip arthroplasty for osteoarthritis. Eight years after implantation of the THA the patient developed a hematogenous TB arthritis in the already implanted hip. During the revision operation the infected hip was found to communicate with the ipsilateral psoas muscle sheath through a
P. Korovessis; M. Stamatakis; M. Repanti
A 39-year-old female with elevated serum cobalt levels from her bilateral hip prostheses presented with a 3-week history of blurred vision in her left eye. Optical coherence tomography revealed patchy degeneration of the photoreceptor-retinal pigment epithelium (RPE) complex. The lesions were hypofluorescent on indocyanine green angiography. We postulate that this is a case of implant-related chorio-retinal cobalt toxicity. PMID:23275221
Ng, Soo K; Ebneter, Andreas; Gilhotra, Jagjit S
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 (UHMW PE) hip joint cups. Nearly 30 out of 48 loosened cups, retrieved 3 weeks to 11 years after implantation, were investigated. Density measurements show a density increase with implantation time and a dependence of these changes from implant position and loading conditions. The rate of extractable constituents also increases with course of time. An increased in vivo conditioned oxidation of the UHMW PE can be demonstrated by infrared (IR) spectrometry. The density increase can be explained by post-crystallization, which is the result of oxidative chain scission. This leads to a reduction of the average molecular weight of the PE and to an increased extractability of constituents. Since these changes have been recognized as the reasons for aging and failing of UHMW PE, the methods of material characterization used in this study for retrieved implants will help to develop suitable in vitro testing and simulating methods. They are the prerequisite for the necessary improvements of the material properties of UHMW PE. PMID:6544798
Eyerer, P; Ke, Y C
INTRODUCTION. There has been some recent concern regarding possible systemic health effects resulting from elevated blood cobalt concentrations in patients with cobalt containing hip implants. To date there are no blood cobalt criteria to help guide physicians when evaluating an individual hip implant patient's risk of developing systemic health effects because historically there was little or no concern about systemic cobalt toxicity in implant patients. OBJECTIVE. Our purpose is to describe recently completed research regarding the relationship between blood cobalt concentrations and clinical health effects. We discuss the possibility of systemic health effects in patients with metal containing implants and propose various blood cobalt concentrations that are not associated with an increased risk of developing certain adverse effects. METHODOLOGY. The primary literature search was conducted using PubMed and Web of Science using the following search terms: cobalt AND (toxicity OR health effects OR cardiotoxicity OR hematological OR endocrine OR immunological OR reproductive OR testicular effects OR neurological OR case report OR cohort OR Roncovite). The searches identified 6786 papers of which 122 were considered relevant. The Agency for Toxic Substances and Disease Registry toxicological profile for cobalt and the U.S. Environmental Protection Agency Office of Research and Development's National Center for Environmental Assessment's documentation on the provisional peer-reviewed toxicity value for cobalt were also utilized to identify secondary literature sources. RESULTS. Our review of the toxicology and medical literature indicates that highly elevated blood cobalt concentrations can result in certain endocrine, hematological, cardiovascular, and neurological effects in animals and/or humans. These studies, in addition to historical clinical findings involving the therapeutic use of cobalt, indicate that significant systemic effects of cobalt will not occur below blood cobalt concentrations of 300 ?g/L in most persons. Some individuals with specific risk factors for increased susceptibility (e.g., severe and sustained hypoalbuminemia) may exhibit systemic effects at lower cobalt blood concentrations. This review also describes several cobalt dosing studies performed with human volunteers that consumed cobalt for 15, 30, or 90 days. Overall, the results of these dosing studies indicate that sustained blood cobalt concentrations averaging 10-70 ?g/L for up to 90 days cause no significant clinical effects (maximum concentrations approached 120 ?g/L). Some proposed blood criteria for assessing implant wear and local tissue damage have been suggested by several medical groups. For example, the UK Medicines and Healthcare Products Regulatory Agency has proposed a blood cobalt guidance value of 7 ?g/L, and the Mayo Clinic has suggested serum cobalt concentrations greater than 10 ?g/L, but both of these values are primarily intended to address implant wear and to alert physicians to the possibility of an increased incidence of local effects. There is a clear lack of consensus regarding how to identify a specific numerical blood concentration of concern and whether whole blood or serum is a better matrix to assess total cobalt concentration. CONCLUSIONS. Based on currently available data, only under very unusual circumstances should a clinician expect that biologically important systemic adverse effects might occur in implant patients with blood cobalt concentrations less than 300 ?g/L. Patients with metal-containing hip implants who exhibit signs or symptoms potentially related to polycythemia, hypothyroidism, neurological, or cardiac dysfunction should be clinically evaluated for these conditions. Polycythemia appears to be the most sensitive endpoint. PMID:24256093
Paustenbach, Dennis J; Galbraith, David A; Finley, Brent L
A general methodology of mixed lubrication analysis and friction prediction for a conforming spherical bearing in hip implants was developed, with particular reference to a typical metal-on-metal hip replacement. Experimental measurement of frictional torque for a similar implant was carried out to validate the theoretical prediction. A ball-in-socket configuration was adopted to represent the articulation between the femoral head and
F. C. Wang; C. Brockett; S. Williams; I. Udofia; J. Fisher; Z. M. Jin
Revision surgeries of total hip arthroplasty are often caused by a deficient structural compatibility of the implant. Two main culprits, among others, are bone-implant interface instability and bone resorption. To address these issues, in this paper we propose a novel type of implant, which, in contrast to current hip replacement implants made of either a fully solid or a foam material, consists of a lattice microstructure with nonhomogeneous distribution of material properties. A methodology based on multiscale mechanics and design optimization is introduced to synthesize a graded cellular implant that can minimize concurrently bone resorption and implant interface failure. The procedure is applied to the design of a 2D left implanted femur with optimized gradients of relative density. To assess the manufacturability of the graded cellular microstructure, a proof-of-concept is fabricated by using rapid prototyping. The results from the analysis are used to compare the optimized cellular implant with a fully dense titanium implant and a homogeneous foam implant with a relative density of 50%. The bone resorption and the maximum value of interface stress of the cellular implant are found to be over 70% and 50% less than the titanium implant while being 53% and 65% less than the foam implant. PMID:22482684
Arabnejad Khanoki, Sajad; Pasini, Damiano
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
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
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, Jorn; Rohlmann, Antonius; Duda, Georg N.; Damm, Philipp
Static load testing of sliding screw-plate hip implants manufactured from Cobalt-Chromium-Molybdenum alloy or 316 LVM stainless steel was performed. Implant angles of 135 degrees and 150 degrees were applied and the telescoping ability eliminated by gluing the screw to the barrel of the implant. In comparison with the results obtained in tests of McLaughlin and Jewett hip implants superior yield loads were determined for both implant angles. Calculations were made of the improvement of implant strength due to telescoping. Implants with a 135 degree angle are recommended for the fixation of unstable trochanteric fractures, as the hip joint load during normal level walking does not exceed the yield load of these implants. PMID:7446052
Jensen, J S
New friction couples, initially intended to limit osteolysis risk due to debris, have enabled larger implant head diameters to be developed to resolve the problem of hip implant dislocation. The Symposium demonstrated that, whatever the configuration, increased head diameter significantly reduced the incidence of dislocation, but that none of the friction couples fulfilled the mechanical and/or biomechanical charge-book for consistently reliable use of large diameter heads. The greatest caution is therefore recommended in their implementation. PMID:21531648
Triclot, P; Gouin, F
This paper analyses the failure of a hip implant, which occurred nine months after the corresponding surgery operation. The base material of the implant is a metallic matrix piece of alloy Ti–6Al–4V, coated by two surface layers; the first one is a 50?m thick layer of pure porous titanium and the other one is a hidroxiapatite ceramic layer of 150?m.
S. Cicero; F. Gutiérrez-Solana; J. A. Álvarez; L. Sánchez
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
Treatment of massive rotator cuff tears can be challenging, especially when tears are considered irreparable or, when repaired, at significant risk of retear. A surgical technique is described using a biodegradable subacromial balloon-shaped spacer (InSpace; Ortho-Space, Caesarea, Israel) that, when implanted between the humeral head and acromion, permits smooth, frictionless gliding, supporting shoulder biomechanics. The specific insertion technique described herein is a simple procedure that can be performed in a day-care or outpatient setting with patients under local anesthesia, thus providing a treatment option for patients with multiple comorbidities complicating or contraindicating surgery, such as reverse arthroplasty under general anesthesia.
Gervasi, Enrico; Cautero, Enrico; Dekel, Assaf
Treatment of massive rotator cuff tears can be challenging, especially when tears are considered irreparable or, when repaired, at significant risk of retear. A surgical technique is described using a biodegradable subacromial balloon-shaped spacer (InSpace; Ortho-Space, Caesarea, Israel) that, when implanted between the humeral head and acromion, permits smooth, frictionless gliding, supporting shoulder biomechanics. The specific insertion technique described herein is a simple procedure that can be performed in a day-care or outpatient setting with patients under local anesthesia, thus providing a treatment option for patients with multiple comorbidities complicating or contraindicating surgery, such as reverse arthroplasty under general anesthesia. PMID:25264508
Gervasi, Enrico; Cautero, Enrico; Dekel, Assaf
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 general methodology of mixed lubrication analysis and friction prediction for a conforming spherical bearing in hip implants was developed, with particular reference to a typical metal-on-metal hip replacement. Experimental measurement of frictional torque for a similar implant was carried out to validate the theoretical prediction. A ball-in-socket configuration was adopted to represent the articulation between the femoral head and the acetabular cup under cyclic operating conditions of representative load and motion. The mixed lubrication model presented in this study was first applied to identify the contact characteristics on the bearing surfaces, consisting of both fluid-film and boundary lubricated regions. The boundary lubricated contact was assumed to occur when the predicted fluid film thickness was less than a typical boundary protein layer absorbed on the bearing surfaces. Subsequently, the friction was predicted from the fluid-film lubricated region with viscous shearing due to both Couette and Poiseuille flows and the boundary protein layer contact region with a constant coefficient of friction. The predicted frictional torque of the typical metal-on-metal hip joint implant was compared with the experimental measurement conducted in a functional hip simulator and a reasonably good agreement was found. The mixed lubrication regime was found to be dominant for the conditions considered. Although the percentage of the boundary lubricated region was quite small, the corresponding contribution to friction was quite large and the resultant friction factor was quite high.
Wang, F. C.; Brockett, C.; Williams, S.; Udofia, I.; Fisher, J.; Jin, Z. M.
In the present study, a probabilistic finite element tool was assessed using an uncemented total hip replacement model. Fully bonded and frictional interfaces were investigated for combinations of three proximal femurs and two implant designs, the Proxima short stem and the IPS hip stem prostheses. The Monte Carlo method was used with two performance indicators: the percentage of bone volume
Carolina Dopico-González; Andrew M. New; Martin Browne
With 332,000 operations carried out every year, the implantation of an artificial hip joint is one of the most common surgical operations performed in the US. According to prognosis which takes the demographical change into account, the number of these operations will increase in the coming years. One of the essential requirements is the perfect reconstruction of the biomechanical functions, especially the knowledge about the center of the hip rotation and the length of the leg. Based on this information it is possible to ensure the right position of the newly set leg during surgery. The aim of this work is to present and evaluate an optical measurement method in order to gather information about the center of the hip joint and the leg length. An appropriate laboratory setup has been designed and implemented in order to evaluate two different approaches: a structured light-method consisting of a DLP-Beamer or a laser source which projects defined patterns onto the patient and a marker-based system. Together with this both methods are combined with custom software to determine the hip joint center and the leg length with an accuracy of around +/- 0.2 inches. The clinical use of the tested approaches would give the surgeon the opportunity to reset the implant-parameters in the course of the surgery. In this way subsequent illnesses such as scoliotic pelvis can be prevented.
Maschke, R.; Lempe, B.; Taudt, Ch.; Rudek, F.; Baselt, T.; Basan, F.; Grunert, R.; Hartmann, P.
BackgroundShort-stemmed hip implants were introduced to conserve proximal bone mass and may facilitate the use of minimally invasive surgery, in which smaller incisions limit access to the joint. This limited access may increase the risk of surgical mal-positioning of the implant, however the sensitivity of femoral loading to such mal-positioning of a short-stemmed implant has not been studied.
Andrew D. Speirs; Markus O. Heller; William R. Taylor; Georg N. Duda; Carsten Perka
This study concerns the fatigue behavior of a C/Peek hip implant. It is now well-established that the extent of bone loss around a total hip arthroplasty stem is related to stress shielding process. Due to a modulus mismatch between the bone and the implant material, the load transfer to the stem decreases the mechanical stimulus needed by the bone to maintain its structure. Because of its low modulus of elasticity and its good resistance to fatigue in aeronautical applications, the Fiber Carbon/Peek composite could potentially replace some of the metal alloys used in hip stem implant. After a literature survey on biomechanical performances of some fiber carbon composites, including AS4/Peek, experimental quasi-static and fatigue compression tests have been performed on AS4/Peek hip implants. The structural and mechanical characterization of the injection moulded composite material has been realized. The prosthesis compression and fatigue behaviour have been studied with a joint-stimulating apparatus immersed in a physiological solution temperature controlled. Instead of the low specimen homogeneity, no fatigue damage has been revealed either by X-ray observations of stiffness measurements, till ten millions of cycles. The quasi-static compressive fracture morphology has been analyzed by S.E.M. and have shown a good fiber matrix bonding. This mechanical results would suggest that AS4/Peek hip stem are worthy of further investigation as implantable prostheses. PMID:9138327
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
Assessment of immune response to implant wear debris in periprosthetic tissue following total hip arthroplasty suggests that multiple factors are involved in the loss implant function. The current study investigated wear debris and the associated immunohistomorphologic changes in tissues from nine patients with historical (gamma air-sterilized) and nine highly-crosslinked UHMWPE implant components. Paraffin embedded tissue sections were evaluated for the presence of histiocytes, giant cells, fibrocartilage/bone and necrosis. To determine the incidence, degree and co-localization of immunohistomorphologic changes and wear, overlapping full-field tissue arrays were collected in brightfield and polarized light. The historical cohort tissues predominantly showed histiocytes associated with significant accumulations of small wear (0.5–2 ?m), and giant cells associated with large wear (?2 ?m). Frequently, focal regions of necrosis were observed in association with wear debris. For the highly-crosslinked cohort, inflammation and associated wear debris were limited, but in tissues from patients revised after implantation times of >2 years a response was observed. Whereas significant amounts of fibrocartilage/bone were observed in patients at earlier implantation times. In both cohorts, tissue responses were more extensive in the retroacetabular or proximal femoral regions. The current findings suggest that wear debris-induced inflammation may be a major contributor to the loss of implant function for both the historical and highly-crosslinked cohorts, but it is not the primary cause of early implant loosening. This study highlights the importance of using a more quantitative and standardized assessment of immunohistomorphologic responses in periprosthetic tissues, and emphasizes differences in specific anatomical regions of individual patient tissues. PMID:20740602
Baxter, Ryan M; Ianuzzi, Allyson; Freeman, Theresa A; Kurtz, Steven M; Steinbeck, Marla J
Assessment of immune response to implant wear debris in periprosthetic tissue following total hip arthroplasty suggests that multiple factors are involved in the loss implant function. The current study investigated wear debris and the associated immunohistomorphologic changes in tissues from nine patients with historical (gamma air-sterilized) and nine highly crosslinked UHMWPE implant components. Paraffin embedded tissue sections were evaluated for the presence of histiocytes, giant cells, fibrocartilage/bone, and necrosis. To determine the incidence, degree and co-localization of immunohistomorphologic changes and wear, overlapping full-field tissue arrays were collected in brightfield and polarized light. The historical cohort tissues predominantly showed histiocytes associated with significant accumulations of small wear (0.5-2 microm), and giant cells associated with large wear (> or =2 microm). Frequently, focal regions of necrosis were observed in association with wear debris. For the highly crosslinked cohort, inflammation and associated wear debris were limited, but in tissues from patients revised after implantation times of >2 years a response was observed. Whereas significant amounts of fibrocartilage/bone were observed in patients at earlier implantation times. In both cohorts, tissue responses were more extensive in the retroacetabular or proximal femoral regions. The current findings suggest that wear debris-induced inflammation may be a major contributor to the loss of implant function for both the historical and highly crosslinked cohorts, but it is not the primary cause of early implant loosening. This study highlights the importance of using a more quantitative and standardized assessment of immunohistomorphologic responses in periprosthetic tissues, and emphasizes differences in specific anatomical regions of individual patient tissues. PMID:20740602
Baxter, Ryan M; Ianuzzi, Allyson; Freeman, Theresa A; Kurtz, Steven M; Steinbeck, Marla J
Background Adverse local tissue reaction (ALTR) is characterized by periprosthetic soft tissue inflammation composed of a mixed inflammatory cell infiltrate, extensive soft tissue necrosis, and vascular changes. Multiple hip implant classes have been reported to result in ALTR, and clinical differences may represent variation in the soft tissue response at the cellular and tissue levels. The purpose of this study was to describe similarities and differences in periprosthetic tissue structure, organization, and cellular composition by conventional histology and immunohistochemistry in ALTR resulting from two common total hip arthroplasty (THA) implant classes. Methods Consecutive patients presenting with ALTR from two major hip implant classes (N?=?54 patients with Dual-Modular Neck implant; N?=?14 patients with Metal-on-Metal implant) were identified from our prospective Osteolysis Tissue Database and Repository. Clinical characteristics including age, sex, BMI, length of implantation, and serum metal ion levels were recorded. Retrieved synovial tissue morphology was graded using light microscopy and cellular composition was assessed using immunohistochemistry. Results Length of implantation was shorter in the DMN group versus MoM THA group (21.3 [8.4] months versus 43.6 [13.8] months respectively; p?0.005) suggesting differences in implant performance. Morphologic examination revealed a common spectrum of neo-synovial proliferation and necrosis in both groups. Macrophages were more commonly present in diffuse sheets (Grade 3) in the MoM relative to DMN group (p?=?0.016). Perivascular lymphocytes with germinal centers (Grade 4) were more common in the DMN group, which trended towards significance (p?=?0.066). Qualitative differences in corrosion product morphology were seen between the two groups. Immunohistochemistry showed features of a CD4 and GATA-3 rich lymphocyte reaction in both implants, with increased ratios of perivascular T-cell relative to B-cell markers in the DMN relative to the MoM group (p?=?0.032). Conclusion Our results demonstrate that both implant classes display common features of neo-synovial proliferation and necrosis with a CD4 and GATA-3 rich inflammatory infiltrate. Qualitative differences in corrosion product appearance, macrophage morphology, and lymphocyte distributions were seen between the two implant types. Our data suggests that ALTR represents a histological spectrum with implant-based features. PMID:25242891
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
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
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.
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.
Background The mechanism of failure of metal-on-metal (MoM) total hip arthroplasty (THA) has been related to a high rate of metal wear debris, which is partly generated from the head-trunnion interface. However, it is not known whether implant fixation is affected by metal wear debris. Patients and methods 49 cases of MoM THA in 41 patients (10 women) with a mean age of 52 (28–68) years were followed with stereoradiographs after surgery and at 1, 2, and 5 years to analyze implant migration by radiostereometric analysis (RSA). Patients also participated in a 5- to 7-year follow-up with measurement of serum metal ions, questionnaires (Oxford hip score (OHS) and Harris hip score (HHS)), and measurement of cup and stem positions and systemic bone mineral density. Results At 1–2 years, mean total translation (TT) was 0.04 mm (95% CI: –0.07 to 0.14; p = 0.5) for the stems; at 2–5 years, mean TT was 0.13 mm (95% CI: –0.25 to –0.01; p = 0.03), but within the precision limit of the method. For the cups, there was no statistically significant TT or total rotation (TR) at 1–2 and 2–5 years. At 2–5 years, we found 4 cups and 5 stems with TT migrations exceeding the precision limit of the method. There was an association between cup migration and total OHS < 40 (4 patients, 4 hips; p = 0.04), but there were no statistically significant associations between cup or stem migration and T-scores < –1 (n = 10), cup and stem positions, or elevated serum metal ion levels (> 7µg/L (4 patients, 6 hips)). Interpretation Most cups and stems were well-fixed at 1–5 years. However, at 2–5 years, 4 cups and 5 stems had TT migrations above the precision limits, but these patients had serum metal ion levels similar to those of patients without measurable migrations, and they were pain-free. Patients with serum metal ion levels > 7 µg/L had migrations similar to those in patients with serum metal ion levels < 7 µg/L. Metal wear debris does not appear to influence the fixation of hip components in large-head MoM articulations at medium-term follow-up. PMID:24847790
S?balle, Kjeld; Jakobsen, Stig Storgaard; Lorenzen, Nina Dyrberg; Mechlenburg, Inger; Stilling, Maiken
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 clinical 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. PMID:19387698
Kuchta, Johannes; Sobottke, Rolf; Eysel, Peer; Simons, Patrick
ECE 331 - Biomedical Instrumentation Department of Electrical & Computer Engineering, UBC Lab #6 screw from the implant once it is successfully implanted. #12;ECE 331 - Biomedical Instrumentation Department of Electrical & Computer Engineering, UBC Deliverables: Â· Your implanted femur D3 D6 D10 Plane 0
Pulfrey, David L.
This paper presents a metrological analysis of hip prosthesis components. When changing ceramic prostheses, the surgeon sometimes finds traces of alloy lying in the insert or the femoral head. These traces can be thin and accurate or as a wide band. From the measurements made on the contact areas of hip prosthesis components, we analyse these phenomena by highlighting the defects of form, waviness and roughness of these surfaces using a novel geometric parameterization (namely modal parameterization). The aim of this work is to isolate these defects to characterize the prostheses components. We show that this parameterization allows a multi-scale analysis of surfaces regardless of the type of wear of the prosthesis, and that the results offer some relevant explanations to the analysis of visible damage on the prostheses. In a later study, we are going to analyse the defects influence on the alteration of the performance of hip prostheses.
Grandjean, J.; Le Goic, G.; Favreliere, H.; Ledoux, Y.; Samper, S.; Formosa, F.; Devun, L.; Gradel, T.
Background Modular neck adapters for hip arthroplasty stems allow the surgeon to modify CCD angle, offset and femoral anteversion intraoperatively. Fretting or crevice corrosion may lead to failure of such a modular device due to high loads or surface contamination inside the modular coupling. Unfortunately we have experienced such a failure of implants and now report our clinical experience with the failures in order to advance orthopaedic material research and joint replacement surgery. The failed neck adapters were implanted between August 2004 and November 2006 a total of about 5000 devices. After this period, the titanium neck adapters were replaced by adapters out of cobalt-chromium. Until the end of 2008 in total 1.4% (n = 68) of the implanted titanium alloy neck adapters failed with an average time of 2.0 years (0.7 to 4.0 years) postoperatively. All, but one, patients were male, their average age being 57.4 years (36 to 75 years) and the average weight 102.3 kg (75 to 130 kg). The failures of neck adapters were divided into 66% with small CCD of 130° and 60% with head lengths of L or larger. Assuming an average time to failure of 2.8 years, the cumulative failure rate was calculated with 2.4%. Methods A series of adapter failures of titanium alloy modular neck adapters in combination with a titanium alloy modular short hip stem was investigated. For patients having received this particular implant combination risk factors were identified which were associated with the occurence of implant failure. A Kaplan-Meier survival-failure-analysis was conducted. The retrieved implants were analysed using microscopic and chemical methods. Modes of failure were simulated in biomechanical tests. Comparative tests included modular neck adapters made of titanium alloy and cobalt chrome alloy material. Results Retrieval examinations and biomechanical simulation revealed that primary micromotions initiated fretting within the modular tapered neck connection. A continuous abrasion and repassivation process with a subsequent cold welding at the titanium alloy modular interface. Surface layers of 10 - 30 ?m titanium oxide were observed. Surface cracks caused by fretting or fretting corrosion finally lead to fatigue fracture of the titanium alloy modular neck adapters. Neck adapters made of cobalt chrome alloy show significantly reduced micromotions especially in case of contaminated cone connection. With a cobalt-chromium neck the micromotions can be reduced by a factor of 3 compared to the titanium neck. The incidence of fretting corrosion was also substantially lower with the cobalt-chromium neck configuration. Conclusions Failure of modular titanium alloy neck adapters can be initiated by surface micromotions due to surface contamination or highly loaded implant components. In the present study, the patients at risk were men with an average weight over 100 kg. Modular cobalt chrome neck adapters provide higher safety compared to titanium alloy material. PMID:20047653
The Technology of Hip Replacement Between 80 and 90% of hips destroyed by rheumatoid arthritis can hip replacement. P rogressive damage to joints becomes increasingly preva- lent as the population ages be restored to useful function and rendered free of pain by total hip arthroplasty. With more than 100 implant
Objective To determine the evidence of effectiveness and safety for introduction of five recent and ostensibly high value implantable devices in major joint replacement to illustrate the need for change and inform guidance on evidence based introduction of new implants into healthcare. Design Systematic review of clinical trials, comparative observational studies, and registries for comparative effectiveness and safety of five implantable device innovations. Data sources PubMed (Medline), Embase, Web of Science, Cochrane, CINAHL, reference lists of articles, annual reports of major registries, summaries of safety and effectiveness for pre-market application and mandated post-market studies at the US Food and Drug Administration. Study selection The five selected innovations comprised three in total hip replacement (ceramic-on-ceramic bearings, modular femoral necks, and uncemented monoblock cups) and two in total knee replacement (high flexion knee replacement and gender specific knee replacement). All clinical studies of primary total hip or knee replacement for symptomatic osteoarthritis in adults that compared at least one of the clinical outcomes of interest (patient centred outcomes or complications, or both) in the new implant group and control implant group were considered. Data searching, abstraction, and analysis were independently performed and confirmed by at least two authors. Quantitative data syntheses were performed when feasible. Results After assessment of 10?557 search hits, 118 studies (94 unique study cohorts) met the inclusion criteria and reported data related to 15?384 implants in 13?164 patients. Comparative evidence per device innovation varied from four low to moderate quality retrospective studies (modular femoral necks) to 56 studies of varying quality including seven high quality (randomised) studies (high flexion knee replacement). None of the five device innovations was found to improve functional or patient reported outcomes. National registries reported two to 12 year follow-up for revision occurrence related to more than 200?000 of these implants. Reported comparative data with well established alternative devices (over 1?200?000 implants) did not show improved device survival. Moreover, we found higher revision occurrence associated with modular femoral necks (hazard ratio 1.9) and ceramic-on-ceramic bearings (hazard ratio 1.0-1.6) in hip replacement and with high flexion knee implants (hazard ratio 1.0-1.8). Conclusion We did not find convincing high quality evidence supporting the use of five substantial, well known, and already implemented device innovations in orthopaedics. Moreover, existing devices may be safer to use in total hip or knee replacement. Improved regulation and professional society oversight are necessary to prevent patients from being further exposed to these and future innovations introduced without proper evidence of improved clinical efficacy and safety. PMID:25208953
Nieuwenhuijse, Marc J; Nelissen, R G H H; Schoones, J W
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. PMID:17237945
Garcia-Elias, Elena; Gil-Garay, Enrique
The transient elastohydrodynamic lubrication (EHL) analysis was performed in this study for a typical metal-on-metal bearing employing a polyethylene backing underneath a metallic cup inlay under dynamic operating conditions of load and speed representative of normal walking. A ball-in-socket configuration was adopted to represent the articulation between the femoral head and the acetabular cup. The governing Reynolds and elasticity equations were solved simultaneously by using both finite difference and finite element methods. The predicted transient film thickness from the present study was compared with the estimation based on the quasi-static analysis. It was found that the polyethylene backing employed in the typical metal-on-metal hip bearing, combined with dynamic squeeze-film action, significantly improved the transient lubricant film thickness under cyclic walking and consequently a fluid film lubrication regime was possible for smooth bearing surfaces with an average roughness less than 0.005 microm. PMID:16199048
Liu, F; Jin, Z M; Hirt, F; Rieker, C; Roberts, P; Grigoris, P
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
The present study investigates the mechanical response of representative volume elements of porous Ti-6Al-4V alloy, to arrive at a desired range of pore geometries that would optimize the reduction in stiffness necessary for biocompatibility with the stress concentration arising around the pore periphery, under physiological loading conditions with respect to orthopedic hip implants. A comparative study of the two is performed with the aid of a newly defined optimizing parameter called pore efficiency that takes into consideration both the stiffness quantity and the stress localization around pores. To perform a detailed analysis of the response of the porous structure over the entire spectrum of loading conditions that a hip implant is subjected to in vivo, the mechanical responses of 3D finite element models of cubic and rectangular parallelepiped geometries, with porosities varying over a range of 10% to 60%, are simulated under representative compressive, flexural as well as combined loading conditions. The results that are obtained are used to suggest a range of pore diameters that lower the effective stiffness and modulus of the implant to around 60% of the stiffness and modulus of dense solid implants while keeping the stress levels within permissible limits.
Roy, Sandipan; Panda, Debojyoti; Khutia, Niloy; Chowdhury, Amit Roy
Introduction The use of metal-on-metal (MoM) total hip arthroplasty (THA) increased in the last decades. A release of metal products (i.e. particles, ions, metallo-organic compounds) in these implants may cause local and/or systemic adverse reactions. Metal ion concentrations in body fluids are surrogate measures of metal exposure. Objective To systematically summarize and critically appraise published studies concerning metal ion concentrations after MoM THA. Methods Systematic review of clinical trials (RCTs) and epidemiological studies with assessment of metal ion levels (cobalt, chromium, titanium, nickel, molybdenum) in body fluids after implantation of metalliferous hip replacements. Systematic search in PubMed and Embase in January 2012 supplemented by hand search. Standardized abstraction of pre- and postoperative metal ion concentrations stratified by type of bearing (primary explanatory factor), patient characteristics as well as study quality characteristics (secondary explanatory factors). Results Overall, 104 studies (11 RCTs, 93 epidemiological studies) totaling 9.957 patients with measurement of metal ions in body fluids were identified and analyzed. Consistently, median metal ion concentrations were persistently elevated after implantation of MoM-bearings in all investigated mediums (whole blood, serum, plasma, erythrocytes, urine) irrespective of patient characteristics and study characteristics. In several studies very high serum cobalt concentrations above 50 µg/L were measured (detection limit typically 0.3 µg/L). Highest metal ion concentrations were observed after treatment with stemmed large-head MoM-implants and hip resurfacing arthroplasty. Discussion Due to the risk of local and systemic accumulation of metallic products after treatment with MoM-bearing, risk and benefits should be carefully balanced preoperatively. The authors support a proposed „time out“ for stemmed large-head MoM-THA and recommend a restricted indication for hip resurfacing arthroplasty. Patients with implanted MoM-bearing should receive regular and standardized monitoring of metal ion concentrations. Further research is indicated especially with regard to potential systemic reactions due to accumulation of metal products. PMID:23950923
Hartmann, Albrecht; Hannemann, Franziska; Lutzner, Jorg; Seidler, Andreas; Drexler, Hans; Gunther, Klaus-Peter; Schmitt, Jochen
In this study, the clinical benefit of the improved accuracy of the Acuros XB (AXB) algorithm, implemented in a commercial radiotherapy treatment planning system (TPS), Varian Eclipse, was demonstrated with beams traversing a high-Z material. This is also the first study assessing the accuracy of the AXB algorithm applying volumetric modulated arc therapy (VMAT) technique compared to full Monte Carlo (MC) simulations. In the first phase the AXB algorithm was benchmarked against point dosimetry, film dosimetry, and full MC calculation in a water-filled anthropometric phantom with a unilateral hip implant. Also the validity of the full MC calculation used as reference method was demonstrated. The dose calculations were performed both in original computed tomography (CT) dataset, which included artifacts, and in corrected CT dataset, where constant Hounsfield unit (HU) value assignment for all the materials was made. In the second phase, a clinical treatment plan was prepared for a prostate cancer patient with a unilateral hip implant. The plan applied a hybrid VMAT technique that included partial arcs that avoided passing through the implant and static beams traversing the implant. Ultimately, the AXB-calculated dose distribution was compared to the recalculation by the full MC simulation to assess the accuracy of the AXB algorithm in clinical setting. A recalculation with the anisotropic analytical algorithm (AAA) was also performed to quantify the benefit of the improved dose calculation accuracy of type 'c' algorithm (AXB) over type 'b' algorithm (AAA). The agreement between the AXB algorithm and the full MC model was very good inside and in the vicinity of the implant and elsewhere, which verifies the accuracy of the AXB algorithm for patient plans with beams traversing through high-Z material, whereas the AAA produced larger discrepancies. PMID:25207577
Ojala, Jarkko; Kapanen, Mika; Sipilä, Petri; Hyödynmaa, Simo; Pitkänen, Maunu
Two-stage revision is one of the most widely accepted procedures to eradicate infection and restore function in infected knee prosthesis; while the use of an articulated spacers is advocated by many as a means to preserve function between stages, no data are available regarding gait parameters after spacer implant. The aim of present study was to assess and compare the
N. Logoluso; C. Champlon; G. Melegati; F. Dell'Oro; C. L. Romanò
There is public concern over the long term systemic health effects of metal released from hip replacement prostheses that use large-diameter metal-on-metal bearings. However, to date there has been no systematic study to determine which organs may be at risk, or the magnitude of any effect. We undertook a detailed cross-sectional health screen at a mean of 8 years after surgery in 35 asymptomatic patients who had previously received a metal-on-metal hip resurfacing (MoMHR) versus 35 individually age and sex matched asymptomatic patients who had received a conventional hip replacement. Total body bone mineral density was 5% higher (mean difference 0.05 g/cm2, P?=?0.02) and bone turnover was 14% lower (TRAP 5b, mean difference ?0.56IU/L, P?=?0.006; osteocalcin, mean difference ?3.08 ng/mL, P?=?0.03) in the hip resurfacing versus conventional hip replacement group. Cardiac ejection fraction was 7% lower (mean absolute difference ?5%, P?=?0.04) and left ventricular end-diastolic diameter was 6% larger (mean difference 2.7 mm, P?=?0.007) in the hip resurfacing group versus those patients who received a conventional hip replacement. The urinary fractional excretion of metal was low (cobalt 5%, chromium 1.5%) in patients with MoMHR, but creatinine clearance was normal. Diuretic prescription was associated with a 40% increase in the fractional excretion of chromium (mean difference 0.5%, P?=?0.03). There was no evidence of difference in neuropsychological, renal tubular, hepatic or endocrine function between groups (P>0.05). Our findings of differences in bone and cardiac function between patient groups suggest that chronic exposure to low elevated metal concentrations in patients with well-functioning MoMHR prostheses may have systemic effects. Long-term epidemiological studies in patients with well-functioning metal on metal hip prostheses should include musculoskeletal and cardiac endpoints to quantitate the risk of clinical disease. PMID:23762480
Prentice, Jennifer R.; Clark, Matthew J.; Hoggard, Nigel; Morton, Allison C.; Tooth, Claire; Paley, Martyn N.; Stockley, Ian; Hadjivassiliou, Marios; Wilkinson, J. Mark
Infection of a total hip replacement (THR) is considered a devastating complication, necessitating its complete removal and thorough debridement of the site. It is undoubted that one stage ex- change, if successful, would provide the best benefit both for the patient and the society. Still the fear of re-infection dominates the surgeonsdecisions and in the majority of cases directs them
Background: No data are available about the sports activity of patients with bone-conserving short-stem hip implants.Hypothesis: Patients can return to a good level of sports activity after implantation of a short-stem hip implant.Study Design: Case series; Level of evidence, 4.Methods: The sports activity level of 68 patients (76 hips) after short-stem hip arthroplasty was assessed for a minimum of 2
Florian Schmidutz; Stefan Grote; Matthias Pietschmann; Patrick Weber; Farhad Mazoochian; Andreas Fottner; Volkmar Jansson
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
Preliminary Results of Implantation in Animal Model and Osteoblast Culture Evaluation of Prototypes of Biomimetic Multispiked Connecting Scaffold for Noncemented Stemless Resurfacing Hip Arthroplasty Endoprostheses
We present the new fixation method for RHA (resurfacing hip arthroplasty) endoprostheses by means of the biomimetic multispiked connecting scaffold (MSC-Scaffold). Such connecting scaffold can generate new type of RHA endoprostheses, that is stemless and fixed entirely without cement. The preprototypes of this MSC-Scaffold were manufactured with modern additive laser additive technology (SLM). The pilot surgical implantations in animal model (two laboratory swine) of MSC-Scaffold preprototypes have showed after two months neither implant loosening, migration, and nor other early complications. From the results of performed histopathological evaluation of the periscaffold spikes bone tissue and 10-day culture of human osteoblasts (NHOst) we can conclude that (1) the scaffolding effect was obtained and (2) to improve the osseointegration of the scaffold spikes, their material surface should be physicochemically modified (e.g., with hydroxyapatite). Some histopathological findings in the periscaffold domain near the MSC-Scaffold spikes bases (fibrous connective tissue and metallic particles near the MSC-Scaffold spikes bases edges) prompt considering the necessity to optimize the design of the MSC-Scaffold in the regions of its interspike space near the spikes bases edges, to provide more room for new bone formation in this region and for indispensable post-processing (glass pearl blasting) after the SLM manufacturing. PMID:23984397
Uklejewski, Ryszard; Rogala, Piotr; Winiecki, Mariusz; Kedzia, Andrzej; Ruszkowski, Piotr
Preliminary results of implantation in animal model and osteoblast culture evaluation of prototypes of biomimetic multispiked connecting scaffold for noncemented stemless resurfacing hip arthroplasty endoprostheses.
We present the new fixation method for RHA (resurfacing hip arthroplasty) endoprostheses by means of the biomimetic multispiked connecting scaffold (MSC-Scaffold). Such connecting scaffold can generate new type of RHA endoprostheses, that is stemless and fixed entirely without cement. The preprototypes of this MSC-Scaffold were manufactured with modern additive laser additive technology (SLM). The pilot surgical implantations in animal model (two laboratory swine) of MSC-Scaffold preprototypes have showed after two months neither implant loosening, migration, and nor other early complications. From the results of performed histopathological evaluation of the periscaffold spikes bone tissue and 10-day culture of human osteoblasts (NHOst) we can conclude that (1) the scaffolding effect was obtained and (2) to improve the osseointegration of the scaffold spikes, their material surface should be physicochemically modified (e.g., with hydroxyapatite). Some histopathological findings in the periscaffold domain near the MSC-Scaffold spikes bases (fibrous connective tissue and metallic particles near the MSC-Scaffold spikes bases edges) prompt considering the necessity to optimize the design of the MSC-Scaffold in the regions of its interspike space near the spikes bases edges, to provide more room for new bone formation in this region and for indispensable post-processing (glass pearl blasting) after the SLM manufacturing. PMID:23984397
Uklejewski, Ryszard; Rogala, Piotr; Winiecki, Mariusz; K?dzia, Andrzej; Ruszkowski, Piotr
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
Several studies proved the beneficial effect of cement augmentation of proximal femoral nail antirotation (PFNA) blades on implant purchase in osteoporotic bone. We investigated the effect of different localizations and amounts of bone cement. Polyurethane foam specimens were instrumented with a PFNA blade and subsequently augmented with PMMA bone cement. Eight study groups were formed based on localization and amount of cement volume related to the blade. All specimens underwent cyclic loading with physiological orientation of the force vector until construct failure. Foam groups were compared between each other and to a cadaveric control group. The experiments revealed a significant dependency of implant purchase on localization and amount of cement. Biomechanically favorable cement positions were found at the implant tip and at the cranial side. However, none of the tested augmentation patterns performed significantly inferior to the cadaveric benchmark. These findings will allow surgeons to further reduce the amount of injected PMMA, decreasing the risk of cement leakage or cartilage damage. PMID:24259367
Sermon, A; Hofmann-Fliri, L; Richards, R G; Flamaing, J; Windolf, M
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
C. H. Kurita
PMMA polymerization is an exothermic phenomenon during which stresses and porosity are observed. An experimental model is devised to directly measure radial forces, to be converted to radial stresses, at the stem/cement interface, and temperatures at both interfaces during cement curing. The effects of stem and bone cement initial temperatures (preheating or precooling vs. room temperature) as well as mixing method (hand vs. vacuum mixing) and cement type (Simplex P vs. Palacos R) on radial stress and temperatures are investigated. Compressive radial residual stresses at the stem/cement interface are measured for hand mixed PMMA with preheated stem, with a maximum magnitude of 1.0 MPa. No radial residual stresses are observed when the stem is initially at room temperature or precooled, suggesting that during curing, bone cement can polymerize away from the stem/cement interface generating radial stress in tension or gaps. The results demonstrate the reverse direction of polymerization for preheated stems. Stem preheating significantly increases transient temperatures at the bone/cement interface and also the risk of bone thermal necrosis, because the exposure time to high temperature is prolonged. The results provide interfacial characteristics for accurate modeling of bone cement polymerization to better understand the debonding process of cemented hip prostheses. PMID:20091924
Madrala, A; Nuño, N
A new generation of hip replacements has been designed incorporating compliant layers to promote fluid film lubrication when the joints are implanted in patients. Tests in the Durham hip function simulator show that the friction in these joints is up to an order of magnitude lower than in currently used prostheses, and because this is due to complete separation of
A Unsworth; M J Pearcy; E F T White; G White
Current outcomes data on revision total hip arthroplasty focuses on specific implants and techniques rather than more general outcomes. We therefore examined a large consecutive series of failed THAs undergoing revision to determine if survivorship and modes of failure differ in comparison to the current data. We retrospectively reviewed the medical records of 1100 revision THAs. The minimum followup was 2 years (mean, 6 years; range, 0–20.4 years). Eighty-seven percent of revision total hips required no further surgery; however, 141 hips (13%) underwent a second revision at a mean of 3.7 years (range, 0.025–15.9 years). Seventy percent (98 hips) had a second revision for a diagnosis different from that of their index revision, while 30% (43 hips) had a second revision for the same diagnosis. The most common reasons for failure were instability (49 of 141 hips, 35%), aseptic loosening (42 of 141 hips, 30%), osteolysis and/or wear (17 of 141 hips, 12%), infection (17 of 141 hips, 12%), miscellaneous (13 of 141 hips, 9%), and periprosthetic fracture (three of 141 hips, 2%). Survivorship for revision total hip arthroplasty using second revision as endpoint was 82% at 10 years. Aseptic loosening and instability accounted for 65% of these failures. Level of Evidence: Level IV, therapeutic (retrospective) study. See the Guidelines for Authors for a complete description of levels of evidence. PMID:18975043
Fehring, Thomas K.; Griffin, William L.; Odum, Susan M.; Masonis, John L.
Uncemented hip replacement matches the best results of classic cemented replacements. With the aim of preserving bone and soft tissue, implants with shorter stems and proximal metaphyseal support have been developed. Likewise, the lack of distal load should avoid cortical diaphyseal remodelling phenomena and the thigh pain of some cylindrical and wedge implants. The resurfacing implant, very popular as a conservative hip replacement in the young adult, has disadvantages associated with the fragility of the neck and with large head metal friction torque. Short stem hip replacement may be a reasonable alternative to classic implants and surface hip replacements. The different designs of conservative short stem implants are analysed, and are classified according to their morphology and biomechanical characteristics. Some medium term series show promising results. PMID:23177948
Valverde-Mordt, C; Valverde-Belda, D
Numerous parameters control the long-term performance of a total hip joint arthroplasty. The articulating motions between the femoral and the acetabular components produce wear debris in a hip implant. Surface roughness, clearance, coefficient of friction and sliding distance are found to be contributing parameters that affect wear rates. Wear produced in a hip implant leads to the loosening of a hip prosthesis and thus failure of the hip implant. Ultra-high-molecular-weight polyethylene (UHMWPE) has been successfully used as an acetabular weight bearing component in the THR applications. Cross-linked UHMWPE was found to improve the lifespan of an artificial hip. A gradient cross-linking of UHMWPE has been observed to be a recent development in implant bearing materials. During in vitro studies, gradient cross-linked UHMWPE showed nearly undetectable wear rates. PMID:18824778
Bhatt, Himanshu; Goswami, Tarun
\\u000a Abstract\\u000a \\u000a \\u000a Objective:\\u000a The objective of the study was to evaluate the influence of the bone cement used during primary hip arthroplasty on brain\\u000a functions assessed at the biochemical and clinical levels. The S100B protein is a biochemical marker of brain damage. Its\\u000a plasma concentration was compared with the results of neuropsychological tests, conducted during the perioperative period.\\u000a \\u000a \\u000a \\u000a \\u000a \\u000a Patients and Methods:
Dariusz Tomaszewski; Zbigniew Rybicki; Marcin Mo?a?ski
Attempts to resurface the hip joint date back to the 1930s. Throughout the last century many designs failed due to defective materials or fixation (or a combination). The metal-on-metal designs pioneered at the end of the century appeared to herald a new era, until difficulties associated with adverse reactions to metal debris were identified. Ultimately, a much narrower range of indications emerged - large, young males appear to be the ideal recipients. Implant design features and component orientation are crucial to the survivorship of these implants. PMID:25329979
Spencer, Robert F
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. PMID:21883049
The term, hip pointer, is applied in the setting of a blunt trauma injury to the iliac crest. It typically occurs in contact and collision sports and can cause significant pain and loss of practice or game time. A direct blow results in subperiosteal edema with hematoma formation within surrounding muscle or soft tissue and bone contusion of the iliac crest. Conservative management with compression, ice, antiinflammatories, and rehabilitation exercises are successful in treating hip pointers. Injection therapy with the use of local anesthetic can be helpful in minimizing pain and increasing function to allow more rapid return to play. PMID:23522513
Hall, Matthew; Anderson, Jeffrey
With extreme UV not ready for HVM for the 20nm and 14nm nodes, double patterning options that extend the use of 193nm immersion lithography beyond the optical resolution limits, such as LELE (Litho-Etch-Litho-Etch) and SADP (Self Aligned Double Patterning), are being used for critical layers for these nodes. LELE requires very stringent overlay capability of the optical exposure tool. The spacer scheme of SADP starts with a conformal film of material around the mandrels and etched along the mandrel sidewalls to form patterns with doubled frequency. SADP, while having the advantage of being a self-aligned process, adds a number of process steps and strict control of the mandrel profile is required. In this paper, we will demonstrate a novel technique - ASDP (Anti-Spacer Double Patterning), which uses only spin-on materials to achieve self-aligned double patterning. After initial resist patterning, an Anti-Spacer Generator (ASG) material is coated on the resist pattern to create the developable spacer region. Another layer of material is then coated and processed to generate the second pattern in between the first resist pattern. We were able to define 37.5nm half pitch pattern features using this technique as well as sub-resolution features for an asymmetric pattern. In this paper we will review the capability of the process in terms of CD control and LWR (line width roughness) and discuss the limitations of the process.
Hyatt, Michael; Huang, Karen; DeVilliers, Anton; Slezak, Mark; Liu, Zhi
A high power, high frequency semiconductor device has a plurality of unit cells connected in parallel. The unit cells each having a controlling electrode and first and second controlled electrodes. A thermal spacer divides at least one of the unit cells i...
S. T. Allen, J. W. Milligan
An improved insulating spacer to reduce the heat transfer between the two panes of glass of double insulated glass comprises an extruded or roll-formed metal spacer together with plastic insulating elements which thermally isolate the metal spacer from the panes of glass while permitting conventional application of the sealant to provide reliable bonding. In one embodiment the plastic insulator comprises
Over 50,000 hip replacements are performed per year in NHS hospitals, independent sector hospitals and treatment centres. Since the concept of low frictional arthroplasty was first introduced, aspirations and lifestyles have changed dramatically. Expectations of outcomes have risen, yet more patients with severe co-morbidity of affluent lifestyle (obesity, diabetes and hypertensive cardiac disease) undergo surgery. Implant survival will be aided
Timothy Guy McWilliams; James R. Parker
Periprosthetic infection after total knee arthroplasty is a devastating complication, and two-stage exchange is the standard of care in North America. Articulating and static spacers have been developed to treat these infections but controversy exists over which method is superior. We performed a systematic review using MEDLINE and other literature search engines identifying 47 articles meeting inclusion criteria producing 2011 spacers for comparison. Articulating spacers had increased range of motion 100.1° vs. 82.9° (P<0.003), lower re-infection rate 7.5% (P<0.0031), facilitated re-implantation (P<0.0011), and developed less bone loss (P<.0001) than did static spacers. This study answers several clinically relevant questions and provides useful information in guiding clinical decision making in treating periprosthetic infection. PMID:24268975
Guild, George N; Wu, Baohua; Scuderi, Giles R
The success achieved with non-cemented hip arthroplasty depends mainly on the stability of the fixation, the quality of the stabilizing bone being just as important as favourable biomechanical conditions. The results of the intensive research and development with respect to the particular features of a non-cemented hip endoprosthesis can be divided into the following basic categories: Biomechanical aspects with special reference to bone related to the design of the prosthesis; material characteristics, such as fatigue strength, tribology, corrosion resistance, and biocompatibility; and development of new materials and coatings to permit direct bonding of implant and bone. With regard to the stem of hip prostheses, the different design parameters of various types are examined to determine their typical design characteristics, such as bearing surface of the collar, geometry of cross section, anatomically adapted shaping, and surface of the implant forming the contact with the bone. The latter can be divided into macroprofiles and macro- and micro-porous coated surfaces. On the other hand, the methods of cementless fixation of acetabular cups can be primarily divided into conical and spherical screw fixation and pegged fixation with additional macroprofiles of porous surfaces. In a separate study of the biomechanical aspects of screwed sockets, the special importance of socket shape and thread geometry are presented with reference to primary stability and long-term fixation of prostheses. PMID:3627790
Ungethüm, M; Blömer, W
A spacer grid assembly is disclosed for retaining a plurality of fuel rods in substantially parallel spaced relation, the spacer grids being formed with rhombic openings defining contact means for engaging from one to four fuel rods arranged in each opening, the spacer grids being of symmetric configuration with their rhombic openings being asymmetrically offset to permit inversion and relative rotation of the similar spacer grids for improved support of the fuel rods. An improved locking mechanism includes tie bars having chordal surfaces to facilitate their installation in slotted circular openings of the spacer grids, the tie rods being rotatable into locking engagement with the slotted openings.
Snyder, Jr., Harold J. (Rancho Santa Fe, CA); Veca, Anthony R. (San Diego, CA); Donck, Harry A. (San Diego, CA)
Generator stator cores are constructed by stacking many layers of magnetic laminations. Ventilation ducts may be inserted between these layers by inserting spacers into the core stack. The ventilation ducts allow for the passage of cooling gas through the core during operation. The spacers or spacer posts are positioned between groups of the magnetic laminations to define the ventilation ducts. The spacer posts are secured with longitudinal axes thereof substantially parallel to the core axis. With this structure, core tightness can be assured while maximizing ventilation duct cross section for gas flow and minimizing magnetic loss in the spacers.
Griffith, John Wesley (Schenectady, NY); Tong, Wei (Clifton Park, NY)
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
There is a need of independent prospective studies about modern generation of hip resurfacing implants. The aim of this propective observational study was to compare the functional outcomes and revision rates with hip resurfacing arthroplasty and total hip arthroplasty and to present the preliminary results at 2 years. Patients included were recruited prospectively in the Partial Pelvic Replacement Hip Project by a single surgeon between January 2007 and January 2010. Patients were assessed with the Harris Hip Score (HHS) and Postel-Merle d'Aubigné (MDA) score and Devane Score. The end point of the study was reoperation for any cause related to the prosthesis. At a mean follow up of 38.6 months there were a total of 142 patients with hip resurfacing (group 1) [100 Durom(®) (Zimmer Inc., Warsaw, IN, USA) and 42 Birmingham Hip Resurfacing(®) (Smith & Nephew, Memphis, TN, USA)] and 278 patients with total hip arthroplasty (group 2). The results showed significantly greater gain of HHS, MDA and Devane score with hip resurfacing procedures. However, considering all the complications, the rate was significantly higher in group 16.4% vs 1.79% in group 2 (P<0.0001). In group 1 we observed 6 complications only concerned males with Durom(®) implants. The follow up of this cohort is still on going and may deliver more information on the evolution of these results in time. PMID:24191180
Pailhé, Régis; Reina, Nicolas; Cavaignac, Etienne; Sharma, Akash; Lafontan, Valérie; Laffosse, Jean-Michel; Chiron, Philippe
Degenerative conditions of the spine represent a group of most common lifestyle associated diseases with significant medical and important social impact. Clinical symptoms and syndromes of surgically considerable degenerative diseases of the spine mostly result from nerve root or spinal cord compression caused by a herniated intervertebral disc or a dorsal osteophyte. Therefore, the main goal of the surgical treatment is decompression of the neural structures by complete removal of the intervertebral disc and the osteophytes followed by insertion of an artificial disc spacer into the remaining space. The most frequently used procedure for treating such findings is called anterior cervical discectomy. Since its first introduction in 1950, several modifications of the original technique have been introduced. Their common feature is that removal of the degenerated intervertebral disc or the osteophytes requires stabilization of the adjacent segments by fusion. Thus, implantation of an interbody spacer results not only in intervertebral space reconstruction, but by immobilizing the adjacent vertebral bodies also in forming a firm bony bridging between them--and ultimately a solid bony block. Our paper provides a review of cervical interbody spacers in the order of their evolution from auto- and allografts, through compact materials, cages and dynamic artificial disks. Furthermore, different types of cage filling materials used for fusion augmentation are also discussed. PMID:20731309
Pataky, F; Gajdos, M; Kat'uch, V
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
Hip fractures include fractures of the head, neck, intertrochanteric, and subtrochanteric regions. Head fractures commonly accompany dislocations. Neck fractures and intertrochanteric fractures occur with greatest frequency in elderly patients with a low bone mineral density and are produced by low-energy mechanisms. Subtrochanteric fractures occur in a predominantly strong cortical osseous region that is exposed to large compressive stresses. Implants used to address these fractures must accommodate significant loads while the fractures consolidate. Complications secondary to hip fractures produce significant morbidity and include infection, nonunion, malunion, decubitus ulcers, fat emboli, deep venous thrombosis, pulmonary embolus, pneumonia, myocardial infarction, stroke, and death. PMID:12934739
Teasdall, Robert D; Webb, Lawrence X
Unlike primary stability of coated cementless implants, their secondary stability has been poorly studied. This paper considers some theoretical aspects of the secondary stability of a coated cementless hip implant in a human femur. The bone is separated from the implant by a thin layer of microscopic peaks and troughs formed on the surface of the coating. The size of
Julia Orlik; Alexei Zhurov; John Middleton
Unlike primary stability of coated cementless implants, their secondary stability has been poorly studied. This paper considers some theoretical aspects of the secondary stability of a coated cementless hip implant in a human femur. The bone is separated from the implant by a thin layer of microscopic peaks and troughs formed on the surface of the coating. The size of
Julia Orlik; Alexei Zhurov; John Middleton
Hip and knee replacement can dramatically improve a patient's quality of life through pain relief and restored function. Fixation of hip and knee replacement implants to bone is critical to the success of the procedure. A variety of roughened surfaces and three-dimensional porous surfaces have been used to enhance biological fixation on orthopedic implants. Recently, highly porous metals have emerged as versatile biomaterials that may enhance fixation to bone and are suitable to a number of applications in hip and knee replacement surgery. This article provides an overview of several processes used to create these implant surfaces.
Muth, John; Poggie, Matthew; Kulesha, Gene; Michael Meneghini, R.
The clinical results after total hip replacements using noncemented stems have shown considerable variability over the years;\\u000a the design and characteristics of the implant seemed to play a role in explaining this fact. The purpose of this paper is\\u000a to report the clinical, radiographic and densitometry results of total hip arthroplasties using a stem designed for noncemented\\u000a implantation and to
Alex Leali; Joseph Fetto
This paper reviews instrumented hip joint replacements, instrumented femoral replacements and instrumented femoral fracture stabilizers. Examination of the evolution of such implants was carried out, including the detailed analysis of 16 architectures, designed by 8 research teams and implanted in 32 patients. Their power supply, measurement, communication, processing and actuation systems were reviewed, as were the tests carried out to evaluate their performance and safety. These instrumented implants were only designed to measure biomechanical and thermodynamic quantities in vivo, in order to use such data to conduct research projects and optimize rehabilitation processes. The most promising trend is to minimize aseptic loosening and/or infection following hip or femoral replacements or femoral stabilization procedures by using therapeutic actuators inside instrumented implants to apply controlled stimuli in the bone-implant interface. PMID:25234709
Soares Dos Santos, Marco P; Ferreira, Jorge Af; Ramos, António; Simões, José Ao; Morais, Raul; Silva, Nuno M; Santos, Paulo M; Reis, Manuel C; Oliveira, Tatiana
Cementless total hip replacement (THR) is rapidly being accepted as the surgery for arthritic diseases of the hip joint. The\\u000a bone-ingrowth rate in porous-type cementless implants was about 90% over 10 years after surgery, showing that biological fixation\\u000a of cementless THR was well maintained on both the stem and cup sides. As for the stress shielding of the femur operated
Harumoto Yamada; Yasuo Yoshihara; Osamu Henmi; Mitsuhiro Morita; Yuichiro Shiromoto; Tomoki Kawano; Arihiko Kanaji; Kennichi Ando; Masato Nakagawa; Naoto Kosaki; Eiichi Fukaya
Wear debris from metal-on-polyethylene articulation in conventional total hip arthroplasty can limit the implant's longevity. Modern ceramic material with high wear resistance and low fracture risk has the potential to extend the lifetime of total hip arthroplasty, which makes the procedure potentially more suitable for young, active patients. Concerns with brittle ceramic material include fracture risk, the "squeak" phenomenon, and potentially a higher dislocation rate secondary to limited neck lengths and liner options. We therefore determined the early dislocation rate in modern ceramic-on-ceramic total hip arthroplasty. In 1635 total hip arthroplasties performed over the 9-year period (1996-2005), we observed three anterior and 15 posterior dislocations (1.1%). All were treated successfully, one with a revision and 17 with closed reduction under general anesthesia. Ceramic-on-ceramic total hip arthroplasty can be a good alternative bearing surface with a low dislocation rate. PMID:17667324
Colwell, Clifford W; Hozack, William J; Mesko, J Wesley; D'Antonio, James A; Bierbaum, Benjamin E; Capello, William N; Jaffe, William L; Mai, Kenny T
Background The purpose of our study was to prospectively report the clinical results of 280 consecutive hips (240 patients) who received a ReCap Hip Resurfacing System implant (Biomet Inc., Warsaw, USA) in a single district general hospital. Literature reports a large variation in clinical results between different resurfacing designs and published results using this particular design are scarce. Methods Mean follow up was 3.3 years (1.0 to 6.3) and four patients were lost to follow-up. All patients were diagnosed with end-stage hip osteoarthritis, their mean age was 54 years and 76.4% of all patients were male. Results There were 16 revisions and four patients reported a Harris Hip Score <70 points at their latest follow up. There were no pending revisions. Kaplan-Meier implant survival probability, with revision for any reason as endpoint, was 93.5% at six years follow-up (95%-CI: 88.8-95.3). There were no revisions for Adverse Reactions to Metal Debris (ARMD) and no indications of ARMD in symptomatic non-revised patients, although diagnostics were limited to ultrasound scans. Conclusions This independent series confirms that hip resurfacing is a demanding procedure, and that implant survival of the ReCap hip resurfacing system is on a critical level in our series. In non-revised patients, reported outcomes are generally excellent. Trial registration ClinicalTrials.gov Identifier: NCT00603395 PMID:23234268
Over the last three decades, tribological studies of polyethylene total hip replacements have been undertaken using a simplified model of normal walking. As hip prostheses are being implanted in younger and more active patients, coupled with the increased wear resistance of crosslinked polyethylene, such in vitro approximations in activity are very limiting. Using a hip joint simulator, the influence of
J. G Bowsher; J. C Shelton
The development of a biotelemetry system that is hermetically sealed within a total hip replacement implant is reported. The telemetry system transmits six channels of stress data to reconstruct the major forces acting on the neck of the prosthesis and uses an induction power coupling technique to eliminate the need for internal batteries. The activities associated with the telemetry microminiaturization, data recovery console, hardware fabrications, power induction systems, electrical and mechanical testing and hermetic sealing test results are discussed.
Boreham, J. F.; Postal, R. B.; Luntz, R. A.
The orientation of the acetabular component is influenced not only by the orientation at which the surgeon implants the component, but also the orientation of the pelvis at the time of implantation. Hence, the orientation of the pelvis at set-up and its movement during the operation, are important. During 67 hip replacements, using a validated photogrammetric technique, we measured how three surgeons orientated the patient's pelvis, how much the pelvis moved during surgery, and what effect these had on the final orientation of the acetabular component. Pelvic orientation at set-up, varied widely (mean (± 2, standard deviation (sd))): tilt 8° (2sd ± 32), obliquity -4° (2sd ± 12), rotation -8° (2sd ± 14). Significant differences in pelvic positioning were detected between surgeons (p < 0.001). The mean angular movement of the pelvis between set-up and component implantation was 9° (sd 6). Factors influencing pelvic movement included surgeon, approach (posterior > lateral), procedure (hip resurfacing > total hip replacement) and type of support (p < 0.001). Although, on average, surgeons achieved their desired acetabular component orientation, there was considerable variability (2sd ± 16) in component orientation. We conclude that inconsistency in positioning the patient at set-up and movement of the pelvis during the operation account for much of the variation in acetabular component orientation. Improved methods of positioning and holding the pelvis are required. PMID:24986939
Grammatopoulos, G; Pandit, H G; da Assunção, R; Taylor, A; McLardy-Smith, P; De Smet, K A; Murray, D W; Gill, H S
The past decade has brought a number of advances in the use of hip arthroscopy to diagnose and treat intra-articular pathology of the hip joint. As such, hip arthroscopy has been used to treat patients who otherwise may have needed a complicated open procedure or have gone untreated. The history and physical examination of the patient as well as imaging modalities, such as magnetic resonance imaging, play a vital role in determining a successful outcome. Patient selection also is an important component of success. As the technique and instrumentation of hip arthroscopy improves, this procedure will become increasingly commonplace in addressing patients with hip pain. PMID:18772686
Yusaf, Michael A; Hame, Sharon L
Background Metal-on-metal (MOM) hip resurfacing arthroplasty (HRA) is in clinical use as an appropriate alternative to total hip arthroplasty in young patients. In this technique, a metal cap is placed on the femoral head to cover the damaged surface of the bone and a metal cup is placed in the acetabulum. Objectives The primary objective of this analysis was to compare the revision rates of MOM HRA using different implants with the benchmark set by the National Institute of Clinical Excellence (NICE). The secondary objective of this analysis was to review the literature regarding adverse biological effects associated with implant material. Review Methods A literature search was performed on February 13, 2012, to identify studies published from January 1, 2009, to February 13, 2012. Results The revision rates for MOM HRA using 6 different implants were reviewed. The revision rates for MOM HRA with 3 implants met the NICE criteria, i.e., a revision rate of 10% or less at 10 years. Two implants had short-term follow-ups and MOM HRA with one of the implants failed to meet the NICE criteria. Adverse tissue reactions resulting in failure of the implants have been reported by several studies. With a better understanding of the factors that influence the wear rate of the implants, adverse tissue reactions and subsequent implant failure can be minimized. Many authors have suggested that patient selection and surgical technique affect the wear rate and the risk of tissue reactions. The biological effects of high metal ion levels in the blood and urine of patients with MOM HRA implants are not known. Studies have shown an increase in chromosomal aberrations in patients with MOM articulations, but the clinical implications and long-term consequences of this increase are still unknown. Epidemiological studies have shown that patients with MOM HRA implants did not have an overall increase in mortality or risk of cancer. There is insufficient clinical data to confirm the teratogenicity of MOM implants in humans. Conclusions Metal-on-metal HRA can be beneficial for appropriately selected patients, provided the surgeon has the surgical skills required for performing this procedure. Plain Language Summary There are many young patients with hip diseases who need to have hip replacement surgery. Although a traditional hip replacement is an acceptable procedure for these patients, some surgeons prefer using a newer technique in young patients called hip resurfacing. In this technique, instead of removing the head of the femoral bone, a metal cap is placed on the femoral head to cover the damaged surface of the bone and a metal cup is placed in the hip socket, similar to the cups used in traditional hip replacement. The analysis of the revision rates (i.e., how soon and in how many patients the surgery needs to be redone) and safety of resurfacing implants showed that generally these implants can last 10 years or more for the majority of young people. Good outcomes can be expected when skilled surgeons perform the surgery in properly selected patients. However, since these implants are made of metal (cobalt and chromium alloy), there is concern about excess metal debris production due to friction between the 2 metal components leading to high levels of metal ions in the blood and urine of patients. The production of metal debris may result in inflammation in the joint or development of a benign soft tissue mass leading to implant failure. However, it has been shown that this risk can be reduced by proper positioning of the implant and the careful selection of patients for this procedure. Little is known about the long-term biological effects of high levels of metal ions in the blood and urine of patients who have received metal implants. There is concern about potential increases in the risk of cancer and the risk of fetal abnormalities, but these effects have not been established yet. However, since cobalt and chromium can pass the placental barrier, implants that are not metal-on-metal are recommended for women at childbearing ages if they
Sehatzadeh, S; Kaulback, K; Levin, L
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 defined and described. Density measurements show a density increase with implantation time and a dependence of these changes from implant position and loading conditions. The rate of extractable constituents also increases with course of time. An increased in vivo conditioned oxidation of the UHMWPE can be demonstrated by infrared (IR) spectrometry. The density increase can be explained by post-crystallization, which is the result of oxidative chain scission. This leads to a reduction of the average molecular weight of the PE and to an increased extractability of constituents. Since these changes have been recognized as the reasons for aging and failing of UHMWPE, the methods of material characterization used in this study for retrieved implants will help to develop suitable in vitro testing and simulating methods. Characteristic damage features of hip cups allow direct relationships with construction characteristics and their improvement. PMID:3199313
Kurth, M; Eyerer, P; Ascherl, R; Dittel, K; Holz, U
Background This study examines the clinical and radiologic results of ceramic-on-ceramic total hip arthroplasties with regard to wear, osteolysis, and fracture of the ceramic after a minimum follow-up of six years. Methods We evaluated the results of a consecutive series of 148 primary ceramic-on-ceramic total hip arthroplasties that had been performed between May 2001 and October 2005 in 142 patients. The mean age was 57.2 years (range, 23 to 81 years). The mean follow-up period was 7.8 years (range, 6.1 to 10.1 years). Preoperative diagnosis was avascular necrosis in 77 hips (52%), degenerative arthritis in 36 hips (24.3%), femur neck fracture in 18 hips (12.2%), rheumatoid arthritis in 15 hips (10.1%), and septic hip sequelae in 2 hips (1.4%). Clinical results were evaluated with the Harris hip score, and the presence of postoperative groin or thigh pain. Radiologic analysis was done with special attention in terms of wear, periprosthetic osteolysis, and ceramic failures. Results The mean Harris hip score improved from 58.3 (range, 10 to 73) to 92.5 (range, 79 to 100) on the latest follow-up evaluation. At final follow-up, groin pain was found in 4 hips (2.7%), and thigh pain was found in 6 hips (4.1%). Radiologically, all femoral stems demonstrated stable fixations without loosening. Radiolucent lines were observed around the stem in 25 hips (16.9%), and around the cup in 4 hips (2.7%). Endosteal new bone formation was observed around the stem in 95 hips (64.2%) and around the cup in 88 hips (59.5%). No osteolysis was observed around the stem and cup. There were 2 hips (1.4%) of inclination changes of acetabular cup, 2 hips (1.4%) of hip dislocation, 1 hip (0.7%) of ceramic head fracture, and 1 hip (0.7%) of squeaking. The Kaplan-Meier survival rate of the prostheses was 98.1% at postoperative 7.8 years. Conclusions The ceramic-on-ceramic total hip arthroplasty produced excellent clinical results and implant survival rates with no detectable osteolysis on a minimum six-year follow-up study. The ceramic-on-ceramic couplings could be a reasonable option of primary total hip arthroplasty for variable indications. PMID:24009902
Choy, Won-Sik; Lee, Sang Ki; Bae, Kyoung Wan; Hwang, Yoon Sub; Park, Chang Kyu
Developmental Dysplasia of the Hip KidsHealth > Parents > Diseases & Conditions > Bones & Muscles > Developmental Dysplasia of the Hip Print A A A Text ... Symptoms Diagnosis Treatment Caring for Your Child Developmental dysplasia of the hip (DDH) is a deformity of ...
Dementia and hip fractures are 2 conditions that are seen primarily in older adults, and both are associated with substantial morbidity and mortality. An individual with dementia is up to 3 times more likely than a cognitively intact older adult to sustain a hip fracture. This may occur via several mechanisms, including (1) risk factors that are common to both outcomes; (2) the presence of dementia increasing hip fracture incidence via intermediate risk factors, such as falls, osteoporosis, and vitamin D; and (3) treatment of dementia causing side effects that increase hip fracture risk. We describe a model that applies these 3 mechanisms to explain the relationship between dementia and hip fractures. Comprehensive understanding of these pathways and their relative influence on the outcome of hip fracture will guide the development of effective interventions and potentially improve prevention efforts. PMID:23569663
Friedman, Susan M.; Menzies, Isaura B.; Bukata, Susan V.; Mendelson, Daniel A.; Kates, Stephen L.
Short stem hip implants have been introduced as a bone preserving surgery for younger and more active people undergoing hip arthroplasty. Although many short stems are now available, clinical results and long-term survival are controversial. The aim of this paper is to describe the features of the short stems and to analyse their clinical results and long-term survival. The short-stem implants reproduce a stress distribution at the level of the proximal femur more similar to the physiological femur limiting the stress-shielding that occur with conventional cementless stems. Though short stems are an alternative to conventional stems, their use is not yet justified despite the promising short and mid-term survival results. Higher incidence of complications, such as periprosthetic fractures and malpositioning of the stem, and the lack of long-term results do not allow to predict what role in the future short stems in total hip replacement may have. PMID:24970038
Castelli, Claudio C; Rizzi, Luigi
Hip arthroplasty is an extremely common orthopaedic procedure and there is a wide array of implants that are in current use in the UK. The follow-up of patients who have undergone insertion of a hip prosthesis is shifting from a consultant-lead hospital service towards primary care. As this change in patient care continues it becomes increasingly important that an accurate description of the radiographic features is communicated to the primary-care practitioner so appropriate specialist input can be triggered. This review focuses on the terminology and classification of hip prostheses. This acts as a precursor for Part 2 of this series, which describes the normal and abnormal radiographic findings following hip prosthesis insertion. PMID:19748000
Pluot, E; Davis, E T; Revell, M; Davies, A M; James, S L J
The reasons leading to the in vivo failure of three Acumatch M-series titanium-alloy modular implants in cementless total hip arthroplasty were investigated. The implants were in service for a period ranging from 18 to 36 months. Two were fractured in vivo and the other was retrieved secondary to aseptic loosening after 18 months in service. Macroscopic examination showed close topographical
Manish Paliwal; D. Gordon Allan; Peter Filip
Metal hip implants used in arthroplastic surgery have an elastic modulus which is an order of magnitude higher than the modulus of the surrounding cortical bone. Therefore the metal implant assumes most of the applied loads resulting in resorption of the unloaded bone material by the human body which can cause the impant to loosen. In addition, patients may experience
Andreas Reinhardt; Suresh G. Advani; Michael H. Santare; Freeman Miller
Sequences for the spacer regions that separate the 16S and 23S ribosomal RNA genes have been determined for four more (strategically placed) archaebacteria. These confirm the general rule that methanogens and extreme halophiles have spacers that contain a single tRNAala gene, while tRNA genes are not found in the spacer region of the true extreme thermophiles. The present study also shows that the spacer regions from the sulfate reducing Archaeglobus and the extreme thermophile Thermococcus (both of which cluster phylogenetically with the methanogens and extreme halophiles) contain each a tRNAala gene. Thus, not only all methanogens and extreme halophiles show this characteristic, but all organisms on the "methanogen branch" of the archaebacterial tree appear to do so. The finding of a tRNA gene in the spacer region of the extreme thermophile Thermococcus celer is the first known phenotypic property that links this organism with its phylogenetic counterparts, the methanogens, rather than with its phenotypic counterparts, the sulfur-dependent extreme thermophiles.
Achenbach-Richter, L.; Woese, C. R.
The management of hip injuries in the athlete has evolved significantly in the past few years with theadvancement of arthroscopic techniques. The application of minimally invasive surgical techniques has facilitated relatively rapid returns to sporting activity in recreational and elite athletes alike. Recent advancements in both hip arthroscopy and magnetic resonance imaging have elucidated several sources of intraarticular pathology that
Bryan T. Kelly; Robert L. Buly
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
Hip resurfacing (HR) has become a widely used surgical intervention for younger patients requiring hip joint arthroplasty. While case reports have been published describing rehabilitation programs following HR, there has yet to be established rehabilitation guidelines. Through experience and clinical reasoning, the following guidelines have been developed based on the patients at the Hospital for Special Surgery. The demographics of the typical HR patient, along with the surgical process are described. Current published literature reporting rehabilitation for patients with arthritic hip pathologies has been incorporated into the guidelines and is presented. The guidelines are divided into three phases, with goals for each phase explained. A progression through phases by way of reaching certain milestones and goals is advocated. PMID:22231958
Siverling, Scott; Felix, Ioonna; Chow, S Betty; Niedbala, Elizabeth; Su, Edwin P
We prepared glucidoamphiphile derivatives from d-glucose, d-galactose and xylitol, in which the glucidic moiety and the hydrophobic alkyl chain are separated by spacer arm E (E=glyceryl, (OEt)2-?-polypropyleneglycyl and butyloxy). Their amphiphile characteristics are compared to those of the corresponding analogs 3-O-alkyl-d-glucopyranoses, 6-O-alkyl-d-galactopyranoses and 1-O-alkyl-d,l-xylitols. We discussed the spacer arm influence on hydrophobic lipophilic balance (HLB), critical micellar concentration (CMC), water
G Goethals; A Fernández; P Martin; M Miñana-Pérez; C Scorza; P Villa; P Godé
Opinion leaders in the field of total hip arthroplasty express antipodal views with bewildering frequency. New trends notwithstanding, Charnley low-friction arthroplasty has a record of outstanding success, and we should attempt to identify specific problems, and address these accordingly. Biological and biomechanical matching remain important and increased attention to meticulous cement technique should favourably improve the long-term performance of cemented implants. The concept of cementless replacement should not, however, be summarily discarded, particularly for the younger patient. The discovery of existing design limitations should lead to further development based on sound scientific research. In an era of exploding technology, cost-containment must remain a pragmatic reality in the provision of a health-care service to the community. At this stage we would recommend a cementless hip replacement for the very young, hybrid replacement (cemented stem, uncemented cup) for the middle-aged and a fully cemented replacement for the elderly. PMID:8042105
Learmonth, I D; Spirakis, A
Introduction: This study aimed to determine the dislocation and reoperation rate, functional outcomes, and the survival rate of the unique subset of very old but lucid and independent patients with hip fractures following a total hip arthroplasty (THA) and geriatric team-coordinated perioperative care. Method: Between 2000 and 2006, previously independent ambulatory patients ?80 years old presenting with an intracapsular hip fracture were given THAs under the care of an integrated orthopedic surgery–geriatric service. Their fracture-related complications, ambulation, mental status, and survival were followed for 5 to 11 years postinjury. Results: Five years postinjury, 57 (61.3%) patients of the original study group were living. In all, 3 (3.2%) patients had postoperative hip dislocations (and 2 patients had dislocation twice) and 2 reoperations were needed within the first postoperative month. There were no hip dislocations or reoperations after the first year. Radiographs obtained on 88% of the surviving patients at 5 years postoperatively showed that all remained unchanged from their immediate postoperative images. Nearly half of the patients were still able to ambulate as they did preoperatively and their mixed-model equation was statistically unchanged. Conclusion: This study of patients >80 years old with previously good functional status demonstrates that with appropriate surgical (best prosthesis, good operating technique, and regional anesthesia) and geriatric (pre- and postoperative assessments, close follow-up, medication adjustments, and fall-prevention instruction) care, they have few hip dislocations and reoperations, survive postfracture at least as long as their noninjured contemporaries, and continue to function and ambulate as they did prior to their injury. PMID:24660092
Monzon, Daniel Godoy; Iserson, Kenneth V.; Jauregui, Jose; Musso, Carlos; Piccaluga, Francisco; Buttaro, Martin
Developmental dysplasia of the hip refers to a continuum of abnor- malities in the immature hip that can range from subtle dysplasia to dislocation. The identification of risk factors, including breech pre- sentation and family history, should heighten a physician's suspicion of developmental dysplasia of the hip. Diagnosis is made by physi- cal examination. Palpable hip instability, unequal leg lengths,
STEPHEN K. STORER; Joe DiMaggio; DAVID L. SKAGGS
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
Twenty-two patients had 36 total hip arthroplasties for painful osteonecrosis of the femoral head. At a mean of 86 months after operation, a complete follow-up evaluation, including physical examination, was obtained in 24 hips in 15 patients. An additional 12 hips in seven patients were followed by telephone interview and radiographic evaluation. Although most patients experienced improved hip function and symptomatic relief from pain as a result of the operation, 10 hips developed heterotopic bone, 5 hips dislocated after operation, 6 hips failed due to aseptic loosening, and 1 hip developed a deep infection, and one patient died due to pulmonary embolism. Neither sex, preoperative steroid dose, nor postoperative mean alternate-day steroid dose could be related to aseptic loosening. However, histologic examination of transilial bone biopsy specimens (7 patients, 13 hips) revealed steroid-induced osteoporosis, by the presence of hyperosteoidosis (increased unmineralized osteoid) and increased bone resorption. Bilateral hip involvement, osteoporosis, and high turnover skeletal remodelling at the cement-bone interface potentially contributed to a failure rate that was higher in this group than that reported for primary hip arthroplasty for other diagnoses. The existence of steroid-induced metabolic bone disease and preexisting renal osteodystrophy may pose a significant threat to the long-term survival of a total hip implant. PMID:3053996
Devlin, V J; Einhorn, T A; Gordon, S L; Alvarez, E V; Butt, K M
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)
In this paper a remarkable statistical link between sunspot cycles and prevalence of hip fractures in the elderly is shown. Hip fractures in old people are due to: 1. increased bone fragility for metabolic bone disease; 2. increased propension to fall. Though it is obvious that a correlation does not imply any causal relationship, reasonable conjectures can be allowed. The hypothesis of an 11-year cyclic variation of ultraviolet radiation as a cause of hip fractures is untenable; one may better assume that solar flares can negatively influence the nervous postural regulation leading to a greater propensity to accidental falls. PMID:1935412
Caniggia, M; Scala, C
The problem of friction couples remains unresolved to this day. Improvements in femoral and acetabulum implant anchorage over the last 20 years have significantly extended total hip replacement (THR) implant lifespan; the formation of wear debris, however, leads to resorption and osteolysis, considerably shortening implant lifespan in active patients. Alumina-alumina friction couples provide an excellent friction coefficient, with wear particles that do not cause any osteolysis. There is, however, a problem of acetabulum anchorage of solid alumina, and the risk of fracture persists with ceramic implants despite improvements in their mechanical properties. Metal-metal couples also display very good tribological behavior, but at the cost of the formation of Co and Cr ions impacting surrounding bone tissue and accumulating in remote organs. The behavior of such "hard-hard" couples greatly depends on implant component positioning and on the consequences of repeated neck-insert contact. Very highly crosslinked polyethylene (PE) shows very significant improvement in terms of wear at five years' follow-up compared to conventional PE, but the behavior of this new concept will need to be monitored in the clinical situation if the disappointments experienced with previous hylamer-type improved PE are to be avoided. All these friction couples need to be validated by prospective clinical studies conducted over more than five years, to provide orthopedic surgeons with an eclectic choice of friction couples adapted to the patient's activity. PMID:19442600
Passuti, N; Philippeau, Jm; Gouin, F
The treatment of the spastic hip in Cerebral Palsy (CP) remains a challenge especially in cases of advance changes. Many options are available and the key for a good outcome is to find the best surgical procedure to an individualized patient. The hip fusion is one of the surgical options. The authors presented a group of spastic CP with painful chronic hip subluxation and dislocation treated with hip fusion with a mean follow-up period of 14.5 years. Surgical technique, post-operative management and outcomes were shown, also with the observations done regarding the evolution of the contralateral hip after the hip fusion. They concluded that the hip arthrodesis is an option for patients with spastic CP with painful subluxation or dislocated hips with the goal of pain relief maintain or improve functional status, and facilitating the care. The best candidate is a young ambulatory patient with normal contralateral hip and normal spinal alignment. PMID:25207734
Fucs, Patricia M De Moraes Barros; Yamada, Helder H
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. PMID:23742233
Since the pioneering period of the early 1960s, total hip replacement has gained in safety, effectiveness and quality, through advances in anesthesia, pain control and less-invasive surgery. New materials have been developed jointly with engineers. Thirty years ago we started to develop a special friction system with alumina on an alumina couple, which avoids osteolysis due to plastic debris. It has also become possible to implant hip prostheses in young people, permitting normal activity and with the hope of keeping the same prosthesis for many years. The authors also review data on foreign body reactions, biomechanics, and bone remodeling. PMID:19718982
Experiments were performed in order to clarify the effect of grid spacers on reflood heat transfer in PWR-LOCA. The flow pattern, the thermal responses and the water accumulation near the grid spacer were investigated by shifting the grid spacer at the mi...
J. Sugimoto, Y. Murao
AIMSTo investigate (1) aerosol lung deposition obtained from two small volume conventional spacers (Babyhaler and Aerochamber) and a home made spacer (modified 500 ml plastic cold drink bottle); (2) the effect of using a face mask or mouthpiece; and (3) the relation between age and pulmonary deposition.METHODSLung deposition of aerosolised technetium-99m DTPA inhaled via spacer was measured in 40 children
H J Zar; E G Weinberg; H J Binns; F Gallie; M D Mann
Total hip arthroplasty has evolved from the first total hip arthroplasty in 1938, through the revolutionization of hip arthroplasty by principles of low friction arthroplasty introduced by Sir John Charnley in 1960s to the present state of the art implants and techniques. The main concern regarding failure of total hip arthroplasty has been the biological response to particulate polyethylene debris generated by conventional metal on polyethylene bearing surfaces leading to osteolysis and aseptic loosening of the prosthesis. Therefore, recent research has been focussing on alternative bearing surfaces to reduce the particulate debris generated. These bearing surfaces include ceramic-polyethylene, metal-metal as well as ceramic-ceramic articulations and have demonstrated lesser friction rates as well as significantly lower wear rates as compared to widely used metal on polyethylene surfaces. Clinical experience until now has shown that metal on metal articulations have significant safety concerns whereas metal-on-highly crosslinked polyethylene, ceramic on ceramic and ceramic on highly crosslinked polyethylene articulations have shown encouraging results to hold promise for wider use in younger and more active patients. This review article discusses positives and drawbacks of various bearing surfaces in current clinical use in total hip arthroplasty as well as briefly explores the newer technologies on the horizon which may even further decrease wear and improve total hip arthroplasty survivorship. PMID:25382913
Kumar, Narinder; Arora, Gen N C; Datta, Barun
Labral tears in the hip may cause painful clicking or locking of the hip, reduced range of motion, and disruption to sports and daily activities. The acetabular labrum aids stabilization of the hip joint, particularly during hip motion. The fibrocartilaginous structure extends the acetabular rim and provides a suction seal around the femoroacetabular interface. Treatment options for labral tears include debridement, repair, and reconstruction. Repair of the labrum has been shown to have better results than debridement. Labral refixation is achieved with sutures anchored into the acetabular rim. The acetabular rim is trimmed either to correct pincer impingement or to provide a bleeding bed to improve healing. Labral repair has shown excellent short-term to midterm outcomes and allows patients to return to activities and sports. Arthroscopic rim trimming and labral refixation comprise an effective treatment for labral tears with an underlying diagnosis of femoroacetabular impingement and are supported by the peer-reviewed literature. PMID:23875153
Philippon, Marc J.; Faucet, Scott C.; Briggs, Karen K.
... the American Academy of Orthopaedic Surgeons. Developmental Dislocation (Dysplasia) of the Hip (DDH) The hip is a “ ... pelvis bone. In babies and children with developmental dysplasia (dislocation) of the hip (DDH), the hip joint ...
Modern total hip replacement is typically effective and durable, but early failures do occur. Component position influences functional outcome, durability, and risk of complications. Surgical robotics provides the detail-oriented surgeon with a robust tool to optimize the accuracy and precision of total hip arthroplasty, with the potential to minimize risk of mechanical failure. This article describes efficient workflows for using surgical robotics to optimize surgical precision without increasing surgical complexity. PMID:25199417
Hepinstall, Matthew S
Fixation using alternative implants for the treatment of hip fractures (FAITH): design and rationale for a multi-centre randomized trial comparing sliding hip screws and cancellous screws on revision surgery rates and quality of life in the treatment of femoral neck fractures
Background Hip fractures are a common type of fragility fracture that afflict 293,000 Americans (over 5,000 per week) and 35,000 Canadians (over 670 per week) annually. Despite the large population impact the optimal fixation technique for low energy femoral neck fractures remains controversial. The primary objective of the FAITH study is to assess the impact of cancellous screw fixation versus sliding hip screws on rates of revision surgery at 24 months in individuals with femoral neck fractures. The secondary objective is to determine the impact on health-related quality of life, functional outcomes, health state utilities, fracture healing, mortality and fracture-related adverse events. Methods/Design FAITH is a multi-centre, multi-national randomized controlled trial utilizing minimization to determine patient allocation. Surgeons in North America, Europe, Australia, and Asia will recruit a total of at least 1,000 patients with low-energy femoral neck fractures. Using central randomization, patients will be allocated to receive surgical treatment with cancellous screws or a sliding hip screw. Patient outcomes will be assessed at one week (baseline), 10 weeks, 6, 12, 18, and 24 months post initial fixation. We will independently adjudicate revision surgery and complications within 24 months of the initial fixation. Outcome analysis will be performed using a Cox proportional hazards model and likelihood ratio test. Discussion This study represents major international efforts to definitively resolve the treatment of low-energy femoral neck fractures. This trial will not only change current Orthopaedic practice, but will also set a benchmark for the conduct of future Orthopaedic trials. Trial registration The FAITH trial is registered at ClinicalTrials.gov (Identifier NCT00761813). PMID:24965132
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
A tube support grid and spacers therefor provide radially inward preloading of heat exchange tubes to minimize stress upon base welds due to differential thermal expansion. The grid comprises a concentric series of rings and spacers with opposing concave sides for conforming to the tubes and V-shaped ends to provide resilient flexibility. The flexibility aids in assembly and in transmitting seismic vibrations from the tubes to a shroud. The tube support grid may be assembled in place to achieve the desired inwardly radial preloading of the heat exchange tubes. Tab and slot assembly further minimizes stresses in the system. The radii of the grid rings may be preselected to effect the desired radially inward preloading.
Ringsmuth, Richard J. (Solano Beach, CA); Kaufman, Jay S. (Del Mar, CA)
Clustered regularly interspaced short palindromic repeats (CRISPR) in bacterial and archaeal DNA have recently been shown to be a new type of anti-viral immune system in these organisms. We here study the diversity of spacers in CRISPR under selective pressure. We propose a population dynamics model that explains the biological observation that the leader-proximal end of CRISPR is more diversified and the leader-distal end of CRISPR is more conserved. This result is shown to be in agreement with recent experiments. Our results show that the CRISPR spacer structure is influenced by and provides a record of the viral challenges that bacteria face. 1) J. He and M. W. Deem, Phys. Rev. Lett. 105 (2010) 128102
Deem, Michael; He, Jiankui
Hip replacement is considered the best option for treatment of displaced intracapsular fracture of the femoral neck (FFN).\\u000a The size of the femoral head is an important factor that influences the outcome when a total hip arthroplasty (THA) is performed:\\u000a implants with a 28mm femoral head are prone to dislocate more than ones with a 32mm. Obviously a large head
G. Solarino; A. Piazzolla; N. Tartaglia; L. Scialpi
What is new and what comes next in artificial hip joints? These are the crucial questions we attempt to answer after accurately surveying the state of the art in the field of hip arthroplasty, especially related to non-metallic materials. Summarizing the present situation, one could safely state that the current generation of hard-on-soft and hard-on-hard hip bearings has become quite effective in exhibiting extremely low degrees of wear when compared to traditional implants made of cobalt-chromium alloys coupled with conventional polyethylene materials or to the primitive alumina materials used in the past. Moreover, at a stage of more than 10 years in the clinical follow-up of new generations of hard-on-hard bearings, and more than 10 years follow-up for highly cross-linked polyethylene materials, we should soon be expecting a new set of officially compiled statistics that show significant reductions in failures due to particle-mediated osteolysis as compared to past statistical compilations. However, further important issues (other than wear) remain unsolved, including structural reliability of advanced ceramic and polyethylene components. Severe challenges yet stand in optimizing the biomaterials choice for significantly extended lifetimes and reduced failure risks. Moreover, joint healing trends are expected to evolve more radically in the next few decades. PMID:23867294
Pezzotti, Giuseppe; Yamamoto, Kengo
Patient demand and surgeon interest in hip resurfacing has recently increased, but surgeons in the United States are relatively\\u000a inexperienced with this procedure. We determined the learning curve associated with hip resurfacing and compared the rate\\u000a of early complications of the first 650 hip resurfacings between five experienced hip surgeons and a national safety survey\\u000a database study we previously published,
Ryan M. Nunley; Jinjun Zhu; Peter J. Brooks; C. Anderson Engh Jr; Stephen J. Raterman; John S. Rogerson; Robert L. Barrack
This prospective study examined patient characteristics and radiographic findings for 89 subjects undergoing total hip resurfacing. Thirteen (14.6%) of 89 hips have required revision. Female sex, smaller implant size, and diagnosis of osteonecrosis were associated with lower device survival. No significant differences in acetabular cup angle and stem angle were observed between revised and nonrevised hips. Revision rates for the first 25 hips were 24% and 8% for the last 64 hips. Females accounted for 56% of subjects 1 to 25 and 23% of subjects 26 to 89. Despite representing only 33% of included subjects, females accounted for 62% of revision procedures. The lower device survival proportion in subjects 1 to 25 could not be attributed to acetabular or femoral component malpositioning and can likely be explained by a significantly higher proportion of females enrolled early in the study. PMID:21131164
Rylander, Lucas S; Milbrandt, Joseph C; Wallace, Adam B; Allan, D Gordon
Total hip arthroplasty (THA), an effective treatment for patients with end-stage arthritic hip conditions, provides dramatic pain relief, enhances mobility, and restores function.The success of THA in older patients, in concert with improvements in techniques and biomaterials, has stimulated demand for this procedure in younger, more active patients hoping to regain full activity. Although young age remains a relative contraindication to THA, the weight of this factor has diminished. Several investigators have reported results of low-friction arthroplasty in young patients. Unfortunately, the value of these studies is limited because of heterogeneous hip pathology in the younger groups, particularly given that preoperative pathology has proved to significantly affect implant survival. In this review of the literature, we focus on THA survival in young, active patients with a preoperative diagnosis of noninflammatory osteoarthritis. PMID:19377644
Daras, Mariza; Macaulay, William
People with very thin figures typically have to alter their clothing for protruding hip bones. This is because diagonal wrinkles radiate from the hip bones. This well-illustrated publication shows how to correct this problem in pants and skirts....
Developmental dysplasia of the hip refers to a continuum of abnormalities in the immature hip that can range from subtle dysplasia to dislocation. The identification of risk factors, including breech presentation and family history, should heighten a physician's suspicion of developmental dysplasia of the hip. Diagnosis is made by physical examination. Palpable hip instability, unequal leg lengths, and asymmetric thigh skinfolds may be present in newborns with a hip dislocation, whereas gait abnormalities and limited hip abduction are more common in older children. The role of ultrasonography is controversial, but it generally is used to confirm diagnosis and assess hip development once treatment is initiated. Bracing is first-line treatment in children younger than six months. Surgery is an option for children in whom nonoperative treatment has failed and in children diagnosed after six months of age. It is important to diagnose developmental dysplasia of the hip early to improve treatment results and to decrease the risk of complications. PMID:17087424
Storer, Stephen K; Skaggs, David L
A 68-year-old man with a previous right total hip arthroplasty presented with acute pain in the right hip, and no associated trauma was reported. The previous hybrid arthroplasty consisted of a ceramic femoral head articulating on an ultra-high-molecular-weight polyethylene liner. The unusual diagnosis of fractured ceramic femoral head was made and an urgent revision arthroplasty was performed to remove the ceramic bearing as well as all implants that may have come into contact with the ceramic. This case report highlights the material properties of ceramics in total hip arthroplasties as well as the importance of regular follow-up in these patients. PMID:24515234
Tucker, Damien; Acharya, Mehool
Plasma spray coatings on titanium alloy total hip replacements (THRs) provide a viable alternative to sintered bead or diffusion-bonded fiber metal ingrowth surfaces. The plasma spray process enables the titanium alloy implant to retain 90% of its fatigue strength, as opposed to less than 50% for sintered or diffusion-bonded cementless devices. Laboratory and clinical evidence suggest that plasma spray cementless THRs perform as well, if not better, than other cementless implants. Clinical trials have demonstrated the superiority of a plasma spray cementless THR (Mallory-Head) over a sintered bead cementless THR (PCA) and the equivalent results to a cemented THR. Plasma spray coatings on titanium alloy hip replacements provide a safe, predictable coating for cementless fixation of THRs in the short to medium range of follow-up periods. PMID:8118992
Bourne, R B; Rorabeck, C H; Burkart, B C; Kirk, P G
In medicine metallic implants are widely used as hip replacement protheses or artificial teeth. The biocompatibility is in all cases the most important requirement. Hydroxyapatite (HAp) is frequently used as coating on metallic implants because of its high acceptance by the human body. In this paper a process is described by which a HAp surface layer is produced by ion implantation with a continuous transition to the bulk material. Calcium and phosphorus ions are successively implanted into titanium under different vacuum conditions by backfilling oxygen into the implantation chamber. Afterwards the implanted samples are thermally treated. The elemental composition inside the implanted region was determined by nuclear analysis methods as (?,?) backscattering and the resonant nuclear reaction 1H( 15N,??) 12C. The results of X-ray photoelectron spectroscopy indicate the formation of HAp. In addition a first biocompatibility test was performed to compare the growing of marrow bone cells on the implanted sample surface with that of titanium.
Baumann, H.; Bethge, K.; Bilger, G.; Jones, D.; Symietz, I.
Introduction Aseptic implant loosening caused by wear debris is a common reason for early implant failure after total hip replacement (THR).\\u000a \\u000a \\u000a \\u000a Materials and methods We prospectively studied 96 patients (110 hips), 48 men and 48 women (mean age 46.8 years, mean body mass index 26.1) who\\u000a had undergone cementless THR (titanium stem, press-fit cup, Al2O3 ball, XLPE liner) at a mean of 17.4 months
Marcus Jäger; Michael Behringer; Christoph Zilkens; Travis Matheney; Rüdiger Krauspe
OBJECTIVES: This paper proposes imaging with 3-dimensional vibroacoustography for postoperatively assessing the uncovered cup area after total hip arthroplasty as a quantitative criterion to evaluate implant fixation. METHODS: A phantom with a bone-like structure covered by a tissue-mimicking material was used to simulate a total hip arthroplasty case. Vibroacoustography images of the uncovered cup region were generated using a two-element confocal ultrasound transducer and a hydrophone inside a water tank. Topological correction based on the geometry of the implant was performed to generate a 3-dimensional representation of the vibroacoustography image and to accurately evaluate the surface. The 3-dimensional area obtained by the vibroacoustography approach was compared to the area evaluated by a 3-dimensional motion capture system. RESULTS: The vibroacoustography technique provided high-resolution, high-contrast, and speckle-free images with less sensitivity to the beam incidence. Using a 3-dimensional-topology correction of the image, we accurately estimated the uncovered area of the implant with a relative error of 8.1% in comparison with the motion capture system measurements. CONCLUSION: Measurement of the cup coverage after total hip arthroplasty has not been well established; however, the covered surface area of the acetabular component is one of the most important prognostic factors. The preliminary results of this study show that vibroacoustography is a 3-dimensional approach that can be used to postoperatively evaluate total hip arthroplasty. The favorable results also provide an impetus for exploring vibroacoustography in other bone or implant surface imaging applications. PMID:23778334
Kamimura, Hermes A. S.; Wang, Liao; Carneiro, Antonio A. O.; Kinnick, Randall R.; An, Kai-Nan; Fatemi, Mostafa
\\u000a Despite the success of surgical implants such as artificial hip, materials used in these procedures still do not satisfy the\\u000a demands of human life time functioning. Currently used materials such as titanium alloys, ceramics and polymers are degraded\\u000a after about a dozen years of use. Diamond coating technology has proven to be efficient in the performance of human joints.\\u000a In
Z. Nibennaoune; D. George; S. Ahzi; Y. Remond; J. Gracio; D. Ruch
Polymeric wear debris produced by articulation of the femoral head against the ultra-high-molecular-weight polyethylene socket of a total hip replacement has been implicated as the main cause of osteolysis and subsequent failure of these implants. Potential solutions to this problem are to employ hard bearing surface combinations such as metal-on-metal or ceramic-on-ceramic prostheses. The aim of this study was to
S. C. Scholes; A. Unsworth; A. A. J. Goldsmith
The purpose of this case study of severe metallosis is to draw the attention of orthopedic surgeons to extremely serious results of this kind in the event of the fracture of the ceramic ball in a total hip prosthesis. Eleven months after implantation of a KJF hip prosthesis with an aluminum oxide ceramic ball in combination with a polyethylene acetabular
I. Kempf; M. Semlitsch
This report examines the clinical performance of three very similar total hip arthroplasty designs with distinctly different bearing surfaces used over the course 10-17 years. Clinical outcomes assessments for each group are compared in the context of varying implant related costs related to the latest technology at the time of surgery. Eighty-one surgeries were studied and differ by bearing surface. In this study, 36 hips are ceramic on polyethylene, 27 are metal on polyethylene and 18 are metal on metal. All polyethylene components are nonhighly cross-linked. The ceramic on polyethylene group has younger patients, on average, and higher percentage of patients with significant polyethylene wear. These groups have an average follow-up time of 8.6 years when assessing functional hip scores, thigh pain, groin pain, revision surgeries and radiographic osteolysis. The implant purchasing cost at the time of surgery was assessed to determine if a correlation exists between outcomes and the more technologically advanced implants use at the time of surgery. Based on midterm clinical outcome assessment, no correlation between initial hospital cost and clinical outcomes of one bearing surface over another can be found. PMID:25002938
Parsons, Christopher; Batson, Ryan; Reighard, Shane; Tanner, Stephanie; Snider, Becky; Pace, Thomas B
This report examines the clinical performance of three very similar total hip arthroplasty designs with distinctly different bearing surfaces used over the course 10-17 years. Clinical outcomes assessments for each group are compared in the context of varying implant related costs related to the latest technology at the time of surgery. Eighty-one surgeries were studied and differ by bearing surface. In this study, 36 hips are ceramic on polyethylene, 27 are metal on polyethylene and 18 are metal on metal. All polyethylene components are nonhighly cross-linked. The ceramic on polyethylene group has younger patients, on average, and higher percentage of patients with significant polyethylene wear. These groups have an average follow-up time of 8.6 years when assessing functional hip scores, thigh pain, groin pain, revision surgeries and radiographic osteolysis. The implant purchasing cost at the time of surgery was assessed to determine if a correlation exists between outcomes and the more technologically advanced implants use at the time of surgery. Based on midterm clinical outcome assessment, no correlation between initial hospital cost and clinical outcomes of one bearing surface over another can be found. PMID:25002938
Parsons, Christopher; Batson, Ryan; Reighard, Shane; Tanner, Stephanie; Snider, Becky; Pace, Thomas B.
Background Evolvements in the design, fixation methods, size, and bearing surface of implants for total hip replacement (THR) have led to a variety of options for healthcare professionals to consider. The need to determine the most optimal combinations of THR implant is warranted. This systematic review evaluated the clinical effectiveness of different types of THR used for the treatment of end stage arthritis of the hip. Methods A comprehensive literature search was undertaken in major health databases. Randomised controlled trials (RCTs) and systematic reviews published from 2008 onwards comparing different types of primary THR in patients with end stage arthritis of the hip were included. Results Fourteen RCTs and five systematic reviews were included. Patients experienced significant post-THR improvements in Harris Hip scores, but this did not differ between impact types. There was a reduced risk of implant dislocation after receiving a larger femoral head size (36 mm vs. 28 mm; RR?=?0.17, 95% CI: 0.04, 0.78) or cemented cup (vs. cementless cup; pooled odds ratio: 0.34, 95% CI: 0.13, 0.89). Recipients of cross-linked vs. conventional polyethylene cup liners experienced reduced femoral head penetration and revision. There was no impact of femoral stem fixation and cup shell design on implant survival rates. Evidence on mortality and complications (aseptic loosening, femoral fracture) was inconclusive. Conclusions The majority of evidence was inconclusive due to poor reporting, missing data, or uncertainty in treatment estimates. The findings warrant cautious interpretation given the risk of bias (blinding, attrition), methodological limitations (small sample size, low event counts, short follow-up), and poor reporting. Long-term pragmatic RCTs are needed to allow for more definitive conclusions. Authors are encouraged to specify the minimal clinically important difference and power calculation for their primary outcome(s) as well CONSORT, PRISMA and STROBE guidelines to ensure better reporting and more reliable production and assessment of evidence. PMID:25003202
Tsertsvadze, Alexander; Grove, Amy; Freeman, Karoline; Court, Rachel; Johnson, Samantha; Connock, Martin; Clarke, Aileen; Sutcliffe, Paul
Sports related injuries to the hip have received relatively little attention, in the part because the clinical assessment, imaging studies, and surgical techniques are less sophisticated. The evolution of hip arthroscopy has offered a less invasive technique that allows for recognition and treatment of hip pathologies that previously went unrecognized. The success of hip arthoscopy is dependent on proper patient selection based on the patient's history and diagnosis. The purpose of this clinical commentary is to outline mechanisms of injury and specific lesions that can be addresses using hip arthoscopy. PMID:21509141
Over the last three centuries, treatment of hip arthritides has evolved from rudimentary surgery to modern total hip arthroplasty (THA), which is considered one of the most successful surgical interventions ever developed. We here review the history of the early hip arthroplasty procedures for hip arthritis that preceded Charley total hip arthroplasty. An evaluation of such past enterprises is relevant, and reminds us of the ephemeral nature of human industriousness, and how medical research and procedures are not isolated developments, but correlate to the social, economical, and cultural framework of their time. PMID:16089067
Gomez, Pablo F; Morcuende, Jose A
...hemi-hip) acetabular metal cemented prosthesis. 888.3370 Section 888.3370...hemi-hip) acetabular metal cemented prosthesis. (a) Identification. A hip...hemi-hip) acetabular metal cemented prosthesis is a device intended to be...
...femoral (hemi-hip) metallic resurfacing prosthesis. 888.3400 Section 888.3400...femoral (hemi-hip) metallic resurfacing prosthesis. (a) Identification. A hip...femoral (hemi-hip) metallic resurfacing prosthesis is a device intended to be...
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.
Although the reduction of frictional torques was the driving force behind the design of the Charnley prosthesis, later concerns about wear and subsequent loosening of this and other hip replacements have dominated debate within the bioengineering community. To stimulate discussion on the role of friction in loosening, a review of the frictional characteristics of different prostheses was undertaken. The use
R. M. Hall; A. Unsworth
Background and purpose Reverse hybrid hip replacement uses a cemented all-polyethylene cup and an uncemented stem. Despite increasing use of this method in Scandinavia, there has been very little documentation of results. We have therefore analyzed the results from the Norwegian Arthroplasty Register (NAR), with up to 10 years of follow-up. Patients and methods The NAR has been collecting data on total hip replacement (THR) since 1987. Reverse hybrid hip replacements were used mainly from 2000. We extracted data on reverse hybrid THR from this year onward until December 31, 2009, and compared the results with those from cemented implants over the same period. Specific cup/stem combinations involving 100 cases or more were selected. In addition, only combinations that were taken into use in 2005 or earlier were included. 3,963 operations in 3,630 patients were included. We used the Kaplan-Meier method and Cox regression analysis for estimation of prosthesis survival and relative risk of revision. The main endpoint was revision for any cause, but we also performed specific analyses on different reasons for revision. Results We found equal survival to that from cemented THR at 5 years (cemented: 97.0% (95% CI: 96.8–97.2); reverse hybrid: 96.7% (96.0–97.4)) and at 7 years (cemented: 96.0% (95.7–96.2); reverse hybrid: 95.6% (94.4–96.7)). Adjusted relative risk of revision of the reverse hybrids was 1.1 (0.9–1.4). In patients under 60 years of age, we found similar survival of the 2 groups at 5 and 7 years, with an adjusted relative risk of revision of reverse hybrids of 0.9 (0.6–1.3) compared to cemented implants. Interpretation With a follow-up of up to 10 years, reverse hybrid THRs performed well, and similarly to all-cemented THRs from the same time period. The reverse hybrid method might therefore be an alternative to all-cemented THR. Longer follow-up time is needed to evaluate whether reverse hybrid hip replacement has any advantages over all-cemented THR. PMID:21999624
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
Modular neck implants are an attractive treatment tool in total hip replacement. Concerns remain about the mechanical stability\\u000a and metal ion release caused by the modular connection. Five different implant designs were investigated in an experimental\\u000a set-up. In vivo conditions were simulated and the long-term titanium release was measured. Finally, the modular connections\\u000a were inspected for corrosion processes and signs
J. Philippe Kretzer; Eike Jakubowitz; Michael Krachler; Marc Thomsen; Christian Heisel
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
Objective The study aims to compare the stress shielding effects of implantable anatomical and traditional prostheses after in vitro total hip joint replacement simulation. The study serves as a biomechanical basis for novel artificial prostheses and for clinical hip joint replacements. Methods Sixteen femoral specimens from adult male corpses were randomly divided into two groups: the traditional prosthesis group implanted into femur specimens using simulated total hip joint replacement (n = 8) and the femoral neck-preserved anatomical prosthesis implantation group that used a collum femoris preserving stem/trabeculae oriented pattern (CFP/TOP) acetabular cup (n = 8). The strain values in the two groups before and after prosthesis implantation were measured at different test points using electric resistance strain gauges. The stress shielding rate was calculated according to the related formula. Results The results showed that the rates of proximal femoral stress shielding were significantly higher at test points 1–10 in the traditional femoral prosthesis transplantation group than in the anatomical prosthesis group (p < 0.05). Conclusions There were different effects of stress shielding between the anatomical and traditional prostheses. Retained femoral anatomical implants should reduce stress shielding and increase the stability of anatomical prosthesis implants. PMID:25174846
[Purpose] This study aimed to determine the effect of varying hip flexion angle on hip muscle activity during isometric contraction in abduction. [Subjects] Twenty-seven healthy men (mean age=21.5?years, SD=1.2) participated in this study. [Methods] Surface electromyography (EMG) was recorded of the upper portion of the gluteus maximus (UGM), lower portion of the gluteus maximus (LGM), tensor fasciae latae (TFL), and gluteus medius (GMed) during isometric contraction under two measurement conditions: hip flexion angle (0, 20, 40, 60, and 80 degrees) and abduction of the hip joint at 20, 40, 60, and 80% maximum strength. Integrated EMG (IEMG) were calculated and normalized to the value of maximum voluntary contraction (MVC). [Results] Results indicated that the IEMG of both the UGM and LGM increased significantly with increases in hip flexion angle, whereas the IEMG of the TFL decreased significantly. The maximum activities of the UGM and the LGM were 85.7 ± 80.8%MVC and 38.2 ± 32.9%MVC at 80 degrees of hip flexion, respectively, and that of the TFL was 71.0 ± 39.0%MVC at 40 degrees of hip flexion. [Conclusion] The IEMG of the GMed did not change with increases in hip flexion angle. Hip flexion angle affected the activity of the GM and TFL during isometric contraction in abduction. PMID:24648628
Fujisawa, Hiroyuki; Suzuki, Hiroto; Yamaguchi, Emi; Yoshiki, Hiromi; Wada, Yui; Watanabe, Aya
A new technique of model surgery using LEGO plates as key-spacers is described. This technique requires less time to set up compared with the conventional plaster model method. It also retains the preoperative setup with the same set of models. Movement of the segments can be measured and examined in detail with LEGO key-spacers. PMID:24045189
Tsang, Alfred Chee-Ching; Lee, Alfred Siu Hong; Li, Wai Keung
Particulate wear debris in totally replaced hips causes adverse local host reactions. The extreme form of such a reaction, aggressive granulomatosis, was found to be a distinct condition and different from simple aseptic loosening. Reactive and adaptive tissues around the totally replaced hip were made of proliferation of local fibroblast like cells and activated macrophages. Methylmethacrylate and high-molecular-weight polyethylene were shown to be essentially immunologically inert implant materials, but in small particulate form functioned as cellular irritants initiating local biological reactions leading to loosening of the implants. Chromium-cobalt-molybdenum is the most popular metallic implant material; it is hard and tough, and the bearings of this metal are partially self-polishing. In total hip implants, prerequisites for longevity of the replaced hip are good biocompatibility of the materials and sufficient tribological properties of the bearings. The third key issue is that the bearing must minimize frictional shear at the prosthetic bone-implant interface to be compatible with long-term survival. Some of the approaches to meet these demands are alumina-on-alumina and metal-on-metal designs, as well as the use of highly crosslinked polyethylene for the acetabular component. In order to avoid the wear-based deleterious properties of the conventional total hip prosthesis materials or coatings, the present work included biological and tribological testing of amorphous diamond. Previous experiments had demonstrated that a high adhesion of tetrahedral amorphous carbon coatings to a substrate can be achieved by using mixing layers or interlayers. Amorphous diamond was found to be biologically inert, and simulator testing indicated excellent wear properties for conventional total hip prostheses, in which either the ball or both bearing surfaces were coated with hydrogen-free tetrahedral amorphous diamond films. Simulator testing with such total hip prostheses showed no measurable wear or detectable delamination after 15,000,000 test cycles corresponding to 15 years of clinical use. The present work clearly shows that wear is one of the basic problems with totally replaced hips. Diamond coating of the bearing surfaces appears to be an attractive solution to improve longevity of the totally replaced hip. PMID:14768485
\\u000a Pelvic, hip, and thigh injuries are relatively rare in the young athlete (1). The young athlete with pelvic or hip pain may present with an acute injury necessitating immediate treatment. An acute\\u000a injury may cause pain in the pelvic, hip, thigh, or even knee region. More commonly, the young athlete will have a chronic\\u000a injury that will limit activities during
Jason H. Nielson
The management of hip injuries has evolved significantly in recent years with the advancement of arthroscopic techniques. These recent surgical advances require establishment of rehabilitation protocols that follow several basic principles including (1) consideration of soft-tissue healing constraints, (2) control of swelling and pain to limit muscular inhibition and atrophy, (3) early range of motion, (4) limitations of weight bearing, (5) early initiation of muscle activity and neuromuscular control, (6) progressive lower extremity strengthening and proprioceptive retraining, (7) cardiovascular training, and (8) sport-specific training. The following protocols should not be considered a cookbook approach to rehabilitation, rather guidelines that are used to achieve consistent outcomes. These guidelines will continue to evolve as we learn more about the hip joint and surrounding musculature. PMID:16638496
Stalzer, Steve; Wahoff, Michael; Scanlan, Molly
Objective: To compare the use of uncemented implants in total hip arthroplasty in patients with rheumathologic diseases and mechanical osteoarthrosis. Methods: We retrospectively evaluated 196 patients who were operated by the Hip and Arthroplasty Surgery Group of the IOT-HCFMUSP between 2005 and 2009. Patients were divided into two groups: mechanical causes (165 patients) and rheumathologic causes (31 patients). Groups were compared between each other in age, gender and follow-up time. Osseointegration rate and percentage of failure in arthroplasty were evaluated. Results: No statistically significant difference was found in osseointegration rates (in both femoral and acetabular components) in both groups. The rates of revision surgery and implant survival also did not show statistically significant differences. Conclusion: The use of uncemented total hip arthroplasty did not show worse results in rheumathologic patients. Level of Evidence III, Retrospective Case Control Study. PMID:24644419
Ejnisman, Leandro; Leonhardt, Nathalia Zalc; Fernandes, Laura Fillipini Lorimier; Leonhardt, Marcos de Camargo; Vicente, José Ricardo Negreiros; Croci, Alberto Tesconi
In this report an integrated approach to the three-dimensional material optimization of femoral components of hip prostheses is described. The effectiveness of using reinforced fiber composites for the material optimization of hip implants has been demonstrated and general guidelines on some material design aspects of total hip replacement (THR), in terms of fiber volume fraction and fiber orientation angles, are provided. A modular program was developed to interface the optimization routine with the finite element code. In this study two cases of cemented and non-cemented THR were investigated. In both cases perfectly bonded interfaces were assumed. Two objective functions were defined based on interface failure criteria and bone adaptive remodeling to avoid interface disruption and to reduce the risk of bone loss. The overall results demonstrated the effectiveness of the technique, which can provide meaningful insights into the fiber-reinforced composite material design of orthopaedic implants. PMID:11574257
Katoozian, H; Davy, D T; Arshi, A; Saadati, U
Production of inflammatory mediators (IM) by cells and specifically macrophages around loosened implants may be responsible for their loosening. Our hypothesis was that different materials give rise to different amounts of these IM. It is thought that alumina\\/alumina for total hip replacement (THR), which has been used for 15 years in our orthopedic department, may produce less IM than other
L. Sedel; J. Simeon; A. Meunier; J. M. Villette; S. M. Launay
Modern hip joint replacements are designed to minimise wear problems. The most popular metal-on-polyethylene components are being updated by harder metal and ceramic combinations. However, this has also been shown to influence the friction moments, which could overload the interface between the implant and the body. In this study custom test apparatus was used to measure the joint moments in
N. E. Bishop; F. Waldow; M. M. Morlock
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
. The authors evaluated the histological findings from periprosthetic material retrieved around acetabular and femoral components of 24 revision operations from 24 patients who had previously received cementless total hip arthroplasty or hemiarthroplasty. The indication for revision was aseptic loosening in 20 patients, technical error during implantation in two patients, periprosthetic femoral fracture with subsequent loosening in one patient, and
M. Repanti; M. Stamatakis; A. Baikousis; Z. Papazisis; P. Korovessis
We report an 85-year-old woman with dementia and dependent for normal life activities who was admitted due to a left periprosthetic tibial fracture. The tibial component was replaced by one with a long stem and she was discharged. Four weeks after the intervention the patient was re-admitted due to an acute prosthetic joint infection. All the components were removed and a bone-cement spacer with a handmade stem with a metal core was implanted. Radiological signs of fracture consolidation were observed after 3 months of follow-up. Due to the previous health status of the patient, it was decided to keep the spacer as a definitive treatment. After 24 months, the patient was able to sit without pain and to stand up with help using a knee brace. There were no radiological or clinical signs of infection. PMID:24551027
Font-Vizcarra, Lluís; Izquierdo, Oscar; García-Nuño, Laura; González, Araceli; Diaz-Brito, Vicenç; Castellanos, Juan
Arthritis is a leading cause of disability, and when nonoperative methods have failed, a prosthetic implant is a cost-effective and clinically successful treatment. Metal-on-metal replacements are an attractive implant technology, a lower-wear alternative to metal-on-polyethylene devices. Relatively little is known about how sliding occurs in these implants, except that proteins play a critical role and that there is a tribological layer on the metal surface. We report evidence for graphitic material in the tribological layer in metal-on-metal hip replacements retrieved from patients. As graphite is a solid lubricant, its presence helps to explain why these components exhibit low wear and suggests methods of improving their performance; simultaneously, this raises the issue of the physiological effects of graphitic wear debris. PMID:22194573
Liao, Y; Pourzal, R; Wimmer, M A; Jacobs, J J; Fischer, A; Marks, L D
The majority of cemented femoral hip replacements fail as a consequence of loosening. One design feature that may affect loosening rates is implant surface finish. To determine whether or not surface finish effects fatigue damage accumulation in a bone cement mantle, we developed an experimental model of the implanted proximal femur that allows visualisation of damage growth in the cement
A. B. Lennon; B. A. O. McCormack; P. J. Prendergast
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
The purpose of this gallery of orthopedic implants was to provide a reference for emergency radiologists to quickly identify\\u000a uncommon devices in the shoulders, hips, and extremities. The cases presented in this exhibit will include unusual arthroplasties\\u000a and prostheses as well as bone graft implants (including allograft and autograft). Bone grafts are frequently used for the\\u000a treatment of bone defects,
Eric White; Darren Lu; Ben Eyer; Chris Gottsegen; Elke Ahlmann; Chris Allison
The authors analyzed the histologic findings from material retrieved during 17 revision operations from 15 patients who had cemented total hip arthroplasty or hemiarthroplasty. In 13 patients, the indication for revision was aseptic loosening. In four patients, technical error during implantation of the prostheses made revision necessary. The histologic pictures in the loosened and nonloosened prostheses were similar, characterized by the presence of a synovial-like membrane at the site corresponding to the hip joint cavity or abutting the implant, underneath which were found aggregates of histiocytes and foreign-body giant cells within a dense fibrous matrix. The main foreign material in all patients consisted of fine granules or larger cement particles. A few polyethylene fibers were also observed in some patients. Metal deposits were found in three patients with titanium alloy implants and extensive loosening. The most interesting aspect of this series was the opportunity it provided to study the progressive development of the synovial-like membrane and the first appearance of the cement granulomas in non-loosened cases. The first signs of the synovial membrane appeared 2.5 months postoperatively, whereas the first cement debris were observed as early as seven months after the implantation of the prosthesis. The hip joint newly formed membrane in the nonloosened cases did not differ histologically from that in the loosened cases. Because the histology of loosened and technically poorly placed nonloosened-prostheses are the same, the authors believe that the mechanism of failure associated with cell macrophage-mediated osteolysis may be the same. PMID:8131328
Korovessis, P; Repanti, M
The basic tribological features of metal-on-metal total hip replacements have been reviewed to facilitate an understanding of the engineering science underpinning the renaissance of these hard-on-hard joints. Metal-on-polymer hip replacements operate in the boundary lubrication regime, thus leading to the design guidance to reduce the femoral head diameter as much as is feasible to minimize frictional torque and volumetric wear. This explains why the gold-standard implant of this form from the past half-century had a diameter of only 22.225 mm (7/8 in). Metal-on-metal implants can operate in the mild mixed lubrication regime in which much of the applied load is supported by elastohydrodynamic films. Correct tribological design leads to remarkably low steady state wear rates. Promotion of the most effective elastohydrodynamic films calls for the largest possible head diameters and the smallest clearances that can reasonably be adopted, consistent with fine surface finishes, good sphericity and minimal structural elastic deformation of the cup on its foundations. This guidance, which is opposite in form to that developed for metal-on-polymer joints, is equally valid for solid (monolithic) metallic heads on metallic femoral stems and surface replacement femoral shells. Laboratory measurements of friction and wear in metal-on-metal joints have confirmed their potential to achieve a very mild form of mixed lubrication. The key lies in the generation of effective elastohydrodynamic lubricating films of adequate thickness compared with the composite roughness of the head and cup. The calculation of the film thickness is by no means easy, but the full procedure is outlined and the use of an empirical formula that displays good agreement with calculations based upon the full numerical solutions is explained. The representation of the lambda ratio, lambda, embracing both film thickness and composite roughness, is described. PMID:16669380
Dowson, D; Jin, Z M
Endodontic implants were introduced back in 1960. Endodontic implants enjoyed few successes and many failures. Various reasons for failures include improper case selection, improper use of materials and sealers and poor preparation for implants. Proper case selection had given remarkable long-term success. Two different cases are being presented here, which have been treated successfully with endodontic implants and mineral trioxide aggregate Fillapex (Andreaus, Brazil), an MTA based sealer. We suggest that carefully selected cases can give a higher success rate and this method should be considered as one of the treatment modalities.
Yadav, Rakesh K.; Tikku, A. P.; Chandra, Anil; Wadhwani, K. K.; Ashutosh kr; Singh, Mayank
In this tutorial we describe the basic principles of the ion implantation technique and we demonstrate that emission Mössbauer spectroscopy is an extremely powerful technique to investigate the atomic and electronic configuration around implanted atoms. The physics of dilute atoms in materials, the final lattice sites and their chemical state as well as diffusion phenomena can be studied. We focus on the latest developments of implantation Mössbauer spectroscopy, where three accelerator facilities, i.e., Hahn-Meitner Institute Berlin, ISOLDE-CERN and RIKEN, have intensively been used for materials research in in-beam and on-line Mössbauer experiments immediately after implantation of the nuclear probes.
Langouche, G.; Yoshida, Y.
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.
Hip dislocation subsequent to hip arthroscopy is a rare complication. We report on a case of low-energy anterior hip dislocation that occurred 5 months after hip arthroscopy, a period notably longer than any previously reported event. The patient was a track and field athlete who presented and received treatment for a labral tear and cam lesion. The athlete then dislocated her hip postoperatively during competitive jumping, a motion that requires significant hip flexion and extension. The most likely cause of the anterior dislocation was failure to close the capsule at the completion of surgery, lending credibility to recent trends in the literature suggesting routine capsular closure. We believe that a partial psoas release also contributed to dynamic hip instability because of increased femoral anteversion in this patient. This case suggests that hip capsule closure should be considered at the completion of every procedure and that a psoas release should be avoided in patients with significant anteversion. Furthermore, the biomechanics of competitive jumping may make these athletes more prone to dislocation and require more conservative return-to-sport recommendations. PMID:24951135
Austin, Daniel C; Horneff, John G; Kelly, John D
INTRODUCTION The aim of this study was to look at the different claims made about hip resurfacing arthroplasty in the popular UK print media and how this relates to findings in the scientific literature. METHODS A review of UK popular print media from January 1992 to June 2011 was performed using the Lexis® Library online news database. Only articles discussing the clinical results of hip resurfacing arthroplasty were included. After excluding duplicates, 49 newspaper articles were found suitable for this study. The main outcome measure was the claims made in popular UK print media about hip resurfacing. These were compared with the scientific publication. We reviewed the trend of use of hip resurfacing prostheses during the same period as reported in the National Joint Registry. RESULTS A disparity was found between the claims in the newspapers and published scientific literature. The initial newspaper articles highlighted only the positive aspects of hip resurfacing arthroplasty, without definitive contemporary evidence backing the claims. Most of these claims were refuted by future scientific publications. The initial positive media reports coincided with an increase in the use of hip resurfacing but the decline coincided with negative reports in the scientific literature. CONCLUSIONS The trend of the newspaper articles and that of the number of hip resurfacing prostheses implanted suggests that the media may have been partly responsible for the increased use of this prosthesis. The subsequent decrease was initiated by the scientific literature. PMID:22943335
Malviya, A; Stafford, GH; Villar, RJF; Villar, RN
During the process of prokaryotic CRISPR adaptation, a copy of a segment of foreign deoxyribonucleic acid referred to as protospacer is added to the CRISPR cassette and becomes a spacer. When a protospacer contains a neighboring target interference motif, the specific small CRISPR ribonucleic acid (crRNA) transcribed from expanded CRISPR cassette can protect a prokaryotic cell from virus infection or plasmid transformation and conjugation. We show that in Escherichia coli, a vast majority of plasmid protospacers generate spacers integrated in CRISPR cassette in two opposing orientations, leading to frequent appearance of complementary spacer pairs in a population of cells that underwent CRISPR adaptation. When a protospacer contains a spacer acquisition motif AAG, spacer orientation that generates functional protective crRNA is strongly preferred. All other protospacers give rise to spacers oriented in both ways at comparable frequencies. This phenomenon increases the repertoire of available spacers and should make it more likely that a protective crRNA is formed as a result of CRISPR adaptation. PMID:24728991
Shmakov, Sergey; Savitskaya, Ekaterina; Semenova, Ekaterina; Logacheva, Maria D.; Datsenko, Kirill A.; Severinov, Konstantin
This article reviews the evaluation of the hip including the clinical history and physical examination. As our understanding of hip pathology evolves, and arthroscopic and other minimally invasive operative techniques improve, the focus is shifting toward earlier identification of hip pathology. Risk factors for the development of arthritis are now well established and include femoral acetabular impingement, labral tearing, developmental dysplasia, and slipped capital femoral epiphysis. Emerging treatment options may address these conditions in the early stages and prevent or slow the progression of hip degeneration. It is vitally important to elucidate intra-articular versus extra-articular pathology of hip pain in every step of the patient encounter: history, physical examination, and imaging. PMID:21419954
Plante, Matthew; Wallace, Roxanne; Busconi, Brian D
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. PMID:21966217
Shabat, Shay; Miller, Larry E; Block, Jon E; Gepstein, Reuven
Background Osteoarthritis of the hip is successfully treated by total hip arthroplasty with metal-on-polyethylene articulation. Polyethylene wear debris can however lead to osteolysis, aseptic loosening and failure of the implant. Large head metal-on-metal total hip arthroplasty may overcome polyethylene wear induced prosthetic failure, but can increase systemic cobalt and chromium ion concentrations. The objective of this study is to compare two cementless total hip arthroplasties: a conventional 28 mm metal-on-polyethylene articulation and a large head metal-on-metal articulation. We hypothesize that the latter arthroplasties show less bone density loss and higher serum metal ion concentrations. We expect equal functional scores, greater range of motion, fewer dislocations, fewer periprosthetic radiolucencies and increased prosthetic survival with the metal-on-metal articulation. Methods A randomized controlled trial will be conducted. Patients to be included suffer from non-inflammatory degenerative joint disease of the hip, are aged between 18 and 80 and are admitted for primary cementless unilateral total hip arthroplasty. Patients in the metal-on-metal group will receive a cementless titanium alloy acetabular component with a cobalt-chromium liner and a cobalt-chromium femoral head varying from 38 to 60 mm. Patients in the metal-on-polyethylene group will receive a cementless titanium alloy acetabular component with a polyethylene liner and a 28 mm cobalt-chromium femoral head. We will assess acetabular bone mineral density by dual energy x-ray absorptiometry (DEXA), serum ion concentrations of cobalt, chromium and titanium, self reported functional status (Oxford hip score), physician reported functional status and range of motion (Harris hip score), number of dislocations and prosthetic survival. Measurements will take place preoperatively, perioperatively, and postoperatively (6 weeks, 1 year, 5 years and 10 years). Discussion Superior results of large head metal-on-metal total hip arthroplasty over conventional hip arthroplasty have been put forward by experts, case series and the industry, but to our knowledge there is no randomized controlled evidence. Conclusion This randomized controlled study has been designed to test whether large head metal-on-metal cementless total hip arthroplasty leads to less periprosthetic bone density loss and higher serum metal ion concentrations compared to 28 mm metal-on-polyethylene cementless total hip arthroplasty. Trial registration Netherlands Trial Registry NTR1399 PMID:18842151
Zijlstra, Wierd P; Bos, Nanne; van Raaij, Jos JAM
Due to the increasing number of total hip arthroplasties performed during the last three decades and the limited long-term survival, mainly because of wear, the number of revisions has increased during the last two years. If the implant itself is still considered to be stable, only head and inlay exchange is necessary. This requires comprehensive knowledge of the characteristics of the articulating materials by the surgeon as the wrong choice of wear couple can lead to early failure for a second time. The aim of this paper is to present considerations and strategies for head and inlay exchange in case of failure, either due to wear of the articulation material or of other indications for revision hip arthroplasty. PMID:21088833
Total hip replacement and hip resurfacing arthroplasty are two popular methods for curing the diseases of hip joints to date. While the technology can be considered to be mature, there are still some problems in practice. So, another method, hemi-hip joint arthroplasty, was introduced in this paper. The structure and materials of the prothesis, its experiments in vitro and the
Lan Chen; Mingzhao Chen; Lantian Chen; Ming Hu; Yiwang Bao
Edge loading causes clinical problems for hard-on-hard hip replacements, and edge loading wear scars are present on the majority of retrieved components. We asked the question: are the lines of action of hip joint muscles such that edge loading can occur in a well-designed, well-positioned acetabular cup? A musculoskeletal model, based on cadaveric lower limb geometry, was used to calculate for each muscle, in every position within the complete range of motion, whether its contraction would safely pull the femoral head into the cup or contribute to edge loading. The results show that all the muscles that insert into the distal femur, patella, or tibia could cause edge loading of a well-positioned cup when the hip is in deep flexion. Patients frequently use distally inserting muscles for movements requiring deep hip flexion, such as sit-to-stand. Importantly, the results, which are supported by in vivo data and clinical findings, also show that risk of edge loading is dramatically reduced by combining deep hip flexion with hip abduction. Patients, including those with sub-optimally positioned cups, may be able to reduce the prevalence of edge loading by rising from chairs or stooping with the hip abducted. © 2013 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 31:1172–1179, 2013. PMID:23575923
van Arkel, Richard J; Modenese, Luca; Phillips, Andrew TM; Jeffers, Jonathan RT
Edge loading causes clinical problems for hard-on-hard hip replacements, and edge loading wear scars are present on the majority of retrieved components. We asked the question: are the lines of action of hip joint muscles such that edge loading can occur in a well-designed, well-positioned acetabular cup? A musculoskeletal model, based on cadaveric lower limb geometry, was used to calculate for each muscle, in every position within the complete range of motion, whether its contraction would safely pull the femoral head into the cup or contribute to edge loading. The results show that all the muscles that insert into the distal femur, patella, or tibia could cause edge loading of a well-positioned cup when the hip is in deep flexion. Patients frequently use distally inserting muscles for movements requiring deep hip flexion, such as sit-to-stand. Importantly, the results, which are supported by in vivo data and clinical findings, also show that risk of edge loading is dramatically reduced by combining deep hip flexion with hip abduction. Patients, including those with sub-optimally positioned cups, may be able to reduce the prevalence of edge loading by rising from chairs or stooping with the hip abducted. PMID:23575923
van Arkel, Richard J; Modenese, Luca; Phillips, Andrew T M; Jeffers, Jonathan R T
In contemporary total hip arthroplasty, instability has been a complication in approximately 2% to 5% of primary surgeries and 5% to 10% of revisions. Due to the reduction in the incidence of wear-induced osteolysis that has been achieved over the last decade, instability now stands as the single most common reason for revision surgery. Moreover, even without frank dislocation, impingement and subluxation are implicated in a set of new concerns arising with advanced bearings, associated with the relatively unforgiving nature of many of those designs. Against that backdrop, the biomechanical factors responsible for impingement, subluxation, and dislocation remain under-investigated relative to their burden of morbidity. This manuscript outlines a 15-year program of laboratory and clinical research undertaken to improve the scientific basis for understanding total hip impingement and dislocation. The broad theme has been to systematically evaluate the role of surgical factors, implant design factors, and patient factors in predisposing total hip constructs to impinge, sublux, and/or dislocate. Because this class of adverse biomechanical events had not lent itself well to study with existing approaches, it was necessary to develop (and validate) a series of new research methodologies, relying heavily on advanced finite element formulations. Specific areas of focus have included identifying the biomechanical challenges posed by dislocation-prone patient activities, quantifying design parameter effects and component surgical positioning effects for conventional metal-on-polyethylene implant constructs, and the impingement/dislocation behavior of non-conventional constructs, quantifying the stabilizing role of the hip capsule (and of surgical repairs of capsule defects), and systematically studying impingement and edge loading of hard-on-hard bearings, fracture of ceramic liners, confounding effects of patient obesity, and subluxation-mediated worsening of third body particle challenge. PMID:25328453
Brown, Thomas D; Elkins, Jacob M; Pedersen, Douglas R; Callaghan, John J
Purpose Determining the etiology of persistent groin pain after hip resurfacing arthroplasty (HRA) can be very challenging, even for\\u000a the experienced surgeon. The purpose of the present study was to evaluate the use of hip arthroscopy as a diagnostic and therapeutic\\u000a tool for the painful hip following resurfacing arthroplasty.\\u000a \\u000a \\u000a \\u000a \\u000a Methods In the present paper, the indications for arthroscopy and the arthroscopic findings
C. Pattyn; R. Verdonk; E. Audenaert
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
We have implemented a sidewall spacer patterning method for novel dual-gate single-electron transistor (DGSET) and metal–oxide–semiconductor-based SET (MOSET) based on the uniform SOI wire, using conventional lithography and processing technology. A 30 nm wide silicon quantum wire is defined by a sidewall spacer patterning method, and depletion gates for two tunnel junctions of the DGSET are formed by the doped polycrystalline
Byung-Gook Park; Dae Hwan Kim; Kyung Rok Kim; Ki-Whan Song; Jong Duk Lee
Total hip arthroplasty reduces pain and restores physical function in patients with hip joint problems. This study examined lifestyle and health-related quality of life before and after total hip arthroplasty in Japanese and Chinese patients. Two hospitals in China recruited 120 patients and 120 Japanese patients matched by age and operative status were drawn from a prospective cohort database. Oxford Hip Score, EuroQol, and characteristics of Asian lifestyle and attitudes toward the operation were assessed. There were no differences between patients from the two countries in quality-of-life-scale scores: postoperative patients had significantly better quality-of-life scores than preoperative patients in both countries. In China, patients who reported that living at home was inconvenient had significantly worse Oxford Hip Scores than those who did not. Mean scores for anxiety items concerning possible dislocation and durability of the implant were significantly higher in Japanese than in Chinese subjects. Our findings suggest that providing information about housing conditions and lifestyles would result in improved quality of life and reduced anxiety in patients with implanted joints. PMID:24845456
Fujita, Kimie; Xia, Zhenlan; Liu, Xueqin; Mawatari, Masaaki; Makimoto, Kiyoko
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
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)
Spacers and valved holding chambers (VHCs) are pressurized metered dose inhaler (pMDI) accessory devices, designed to overcome problems that patients commonly experience when administering aerosol via a pMDI. Spacers were developed in direct response to patient-related issues with pMDI technique, particularly, poor coordination between actuation and inhalation, and local side-effects arising from oropharyngeal deposition. Current clinical guidelines indicate the need for widespread prescription and use of spacers, but, despite their apparent ubiquity, the devices themselves are, unfortunately, all too commonly "disused" by patients. An understanding of the background from which spacers developed, and the key factors influencing the optimization of the spacer and the later VHC, is crucial to developing an appreciation of the potential of these devices, both contemporary and future, for improving the delivery of pressurized aerosols to patients. This review, informed by a full patent search and an extensive scientific literature review, takes into account the clinical and laboratory evidence, commercial developments, and the sometimes serendipitous details of scientific anecdotes to form a comprehensive perspective on the evolution of spacers, from their origins, in the early days of the pMDI, up to the present day. PMID:25054481
Nikander, Kurt; Nicholls, Clare; Denyer, John; Pritchard, John
Opponents associate minimally invasive total hip replacement (THR) with additional risks, potentially resulting in increased implant failure rates. The purpose was to document complications, quality of implant positioning and five-year survivorship of THR using the AMIS approach and to test the hypothesis that eventual high complication and revision rates would be limited to an early series and be avoided by junior surgeons who get trained by a senior surgeon. A consecutive series of 150 primary THR implanted during the introduction of the AMIS technique in the department was retrospectively analysed for complications, implant positioning and implant survival after a minimum of five years. Survivorship curves of implants were compared between different surgeons and time periods. Due to implant revision for any reason the five-year survival rate was 94.6%, 78.9% for the first 20 and 96.8% for the following 130 AMIS procedures (p = 0.001). The hazard ratio for implant failure was 0.979 indicating a risk reduction of 2% every further case. The five-year implant survivorship of those procedures performed by two junior surgeons was 97.7%. We conclude that adoption of AMIS temporarily exposed patients to a higher risk of implant revisions, which normalised after the first 20 cases and that experience from a single surgeon's learning curve could effectively be taught to junior surgeons. PMID:24500832
Müller, Daniel A; Zingg, Patrick O; Dora, Claudio
One of the most important issues in the modern total hip arthroplasty (THA) is the bearing surface. Extensive research on bearing surfaces is being conducted to seek an ideal bearing surface for THA. The ideal bearing surface for THA should have superior wear characteristics and should be durable, bio-inert, cost-effective, and easy to implant. However, bearing surfaces that are currently being implemented do not completely fulfill these requirements, especially for young individuals for whom implant longevity is paramount. Even though various new bearing surfaces have been investigated, research is still ongoing, and only short-term results have been reported from clinical trials. Future bearing surfaces can be developed in the following ways: (1) change in design, (2) further improvement of polyethylene, (3) surface modification of the metal, (4) improvement in the ceramic, and (5) use of alternative, new materials. One way to reduce wear and impingement in THA is to make changes in its design by using a large femoral head, a monobloc metal shell with preassembled ceramic liner, dual mobility cups, a combination of different bearing surfaces, etc. Polyethylene has improved over time with the development of highly crosslinked polyethylene. Further improvements can be made by reinforcing it with vitamin E or multiwalled carbon nanotubes and by performing a surface modification with a biomembrane. Surface modifications with titanium nitride or titanium niobium nitride are implemented to try to improve the metal bearings. The advance to the fourth generation ceramics has shown relatively promising results, even in young patients. Nevertheless, further improvement is required to reduce fragility and squeaking. Alternative materials like diamond coatings on surfaces, carbon based composite materials, oxidized zirconium, silicon nitride, and sapphire are being sought. However, long-term studies are necessary to confirm the efficacy of these surfaces after enhancements have been made with regard to fixation technique and implant quality. PMID:24605198
). To increase hip circumference: 4. With tissue paper under the pattern, spread the verti- cal slash one-fourth the total increase you need at the hip. Keep the edges of the slash parallel below the horizontal slash, which will lap (Fig. 3). To decrease hip... circumference: 4. Lap the pattern one-fourth the total decrease you need at the vertical slash. Keep the lap uniform in width from the horizontal line to the hem. The lap will taper to nothing at the waistline seam, and the horizontal slash will spread (Fig...
Pseudallescheria boydii infection of the hip joint was diagnosed 2.5 years after implantation of a prosthetic joint in a woman with rheumatoid arthritis. Cure was achieved with a 10-month course of voriconazole coupled with removal of the prosthesis and repeat surgical debridement. Pseudallescheria boydii is an environmental mold that can cause osteoarticular infection, most often not only after local trauma but also after local injections and surgical procedures. Hip involvement was rarely reported, and this is the first description of a prosthetic joint infection with Scedosporium sp. PMID:21681069
Gottesman-Yekutieli, Tamar; Shwartz, Orna; Edelman, Alexander; Hendel, David; Dan, Michael
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) , 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.
To evaluate the current literature about how successfully periprosthetic hip joint infections can be managed by debridement and prosthesis retention. A literature search was performed through PubMed until September 2013. Search terms were “DAIR (debridement, antibiotics, irrigation, and retention)” alone and in combination with “hip” as well as “hip infection + prosthesis retention”. A total of 11 studies reporting on 292 cases could be identified. Five different treatment modalities have been described with varying success rates (debridement-21% infection eradication rate; debridement + lavage-75% infection eradication rate; debridement, lavage, with change of modular prosthesis components-70.4% infection eradication rate; debridement, lavage, change of modular prosthesis components + vacuum-assisted closure-92.8% infection eradication rate; acetabular cup removal + spacer head onto retained stem-89.6% infection eradication rate). With regard to the postoperative antibiotic therapy, no general consensus could be drawn from the available data. Debridement, antibiotic therapy, irrigation, and prosthesis retention is an acceptable solution in the management of early and acute hematogenous periprosthetic hip joint infections. The current literature does not allow for generalization of conclusions with regard to the best treatment modality. A large, multi-center study is required for identification of the optimal treatment of these infections. PMID:25035823
Anagnostakos, Konstantinos; Schmitt, Cornelia
Background Dynamic interspinous spacers, such as X-stop, Coflex, DIAM, and Aperius, are widely used for the treatment of lumbar spinal stenosis. However, controversy remains as to whether dynamic interspinous spacer use is superior to traditional decompressive surgery. Methods Medline, Embase, Cochrane Library, and the Cochrane Controlled Trials Register were searched during August 2013. A track search was performed on February 27, 2014. Study was included in this review if it was: (1) a randomized controlled trial (RCT) or non-randomized prospective comparison study, (2) comparing the clinical outcomes for interspinous spacer use versus traditional decompressive surgery, (3) in a minimum of 30 patients, (4) with a follow-up duration of at least 12 months. Results Two RCTs and three non-randomized prospective studies were included, with 204 patients in the interspinous spacer (IS) group and 217 patients in the traditional decompressive surgery (TDS) group. Pooled analysis showed no significant difference between the IS and TDS groups for low back pain (WMD: 1.2; 95% CI: ?10.12, 12.53; P?=?0.03; I2?=?66%), leg pain (WMD: 7.12; 95% CI: ?3.88, 18.12; P?=?0.02; I2?=?70%), ODI (WMD: 6.88; 95% CI: ?14.92, 28.68; P?=?0.03; I2?=?79%), RDQ (WMD: ?1.30, 95% CI: ?3.07, 0.47; P?=?0.00; I2?=?0%), or complications (RR: 1.39; 95% CI: 0.61, 3.14; P?=?0.23; I2?=?28%). The TDS group had a significantly lower incidence of reoperation (RR: 3.34; 95% CI: 1.77, 6.31; P?=?0.60; I2?=?0%). Conclusion Although patients may obtain some benefits from interspinous spacers implanted through a minimally invasive technique, interspinous spacer use is associated with a higher incidence of reoperation and higher cost. The indications, risks, and benefits of using an interspinous process device should be carefully considered before surgery. PMID:24809680
Wu, Ai-Min; Zhou, Yong; Li, Qing-Long; Wu, Xin-Lei; Jin, Yong-Long; Luo, Peng; Chi, Yong-Long; Wang, Xiang-Yang
Total hip arthroplasty (THA) can be challenging in Jehovah's Witnesses because of the potential for blood loss. Because these patients will not accept blood transfusions, multiple strategies to prevent blood loss have been developed. The purpose of this study was to report implant survivorship, clinical outcomes, radiographic outcomes, morbidity, and mortality of Jehovah's Witnesses undergoing primary THA. Databases from two institutions were reviewed to identify 53 patients (55 hips) who were Jehovah's Witnesses and had a primary total hip arthroplasty. There were 27 women and 26 men who had a mean age of 63 years (range 35-94 years), and a mean follow-up of 63 months (range 24-120 months). All Jehovah's Witnesses had a comprehensive perioperative blood management strategy employed by a coordinated medical and surgical team. Mean post-operative Harris Hip Scores were 86 points, and implant survivorship was 97%. There were two aseptic revisions for osteolysis and component loosening. There were no mortalities, and three minor surgical and two minor medical complications occurred during the study. Excellent clinical outcomes were found for Jehovah's Witness undergoing total hip arthroplasty using a comprehensive blood management protocol. We believe that the use of a specialised blood management protocol involving a team approach to preoperative evaluation, appropriate anaesthesia, and surgical and postoperative management was responsible for minimising complications. Total hip arthroplasty is safe and efficacious in this patient group if proper preoperative safeguards are utilised. PMID:24318363
Harwin, Steven F; Pivec, Robert; Naziri, Qais; Issa, Kimona; Mont, Michael A
We have studied the efficacy and acceptability of a new inhalation spacer device. The functional principle of the device, differing from that of conventional spacers, is based on evaporation of the propellant during circular movement of the aerosol in a small spherical chamber. We assessed the bronchodilating effect of salbutamol (Salbuvent) inhaled with the new spacer (Rondo) compared with salbutamol (Ventoline) inhaled with the spacer Volumatic and with salbutamol (Salbuvent) inhaled with a conventional metered dose actuator using a double-blind cross-over arrangement. Fifteen asthmatic patients were treated over a period of 4 weeks. They used each of the three different devices for 2-3 days every week. Peak expiratory flow rates were recorded every morning after one and after two puffs of the study drugs. The bronchodilator responses to the three treatments were similar within narrow ranges of estimate. By visual analogue scale assessment the new spacer was significantly easier to handle (P < 0.05) and more convenient to carry around (P < 0.01) than Volumatic. PMID:8453959
Stenius-Aarniala, B; Kiviranta, K; Poppius, H
The Long Spacer, a component of the International Space Station, arrives and is moved to its test stand in the northeast corner of the high bay in KSC's Space Station Processing Facility. The Long Spacer provides structural support for the outboard Photovoltaic Modules that supply power to the station. Now just a structure, the Long Spacer will have attached to it as part of processing a heat dissipation radiator and two Pump and Flow Control subassemblies that circulate ammonia to cool the solar array electronics. Also to be mounted are ammonia fluid lines as part of the cooling system and the cabling necessary for power and control of the station. The Long Spacer becomes an integral part of a station truss segment when it is mated with the Integrated Equipment Assembly, which stores the electrical power generated by the solar arrays for use by the station modules. The Long Spacer is being processed in preparation for STS-97, currently planned for launch aboard Discovery in April 1999.
In the curative radiotherapy of localized prostate cancer, improvements in biochemical control observed with dose escalation have been counterbalanced by an increase in radiation-induced toxicity. The injection of biodegradable spacers between prostate and rectum represents a new frontier in the optimization of radiotherapy treatments for patients with localized disease. Transperineal injection of different types of spacers under transrectal ultrasound guidance allows creating a 7-to-20 mm additional space between the prostate and the anterior rectal wall lasting 3 to 12 months. Dosimetrically, a relative reduction in the rectal volume receiving at least 70 Gy (V70) in the order of 43% to 84% is observed with all types of spacers, regardless of the radiotherapy technique used. Preliminary clinical results show for all spacers a good tolerance and a possible reduction in the acute side effects rate. The aim of the present systematic review of the literature is to report on indications as well as dosimetric and clinical advantages of the different types of prostate-rectum spacers commercially available (hydrogel, hyaluronic acid, collagen, biodegradable balloon). PMID:24746454
Zilli, T; Benz, E; Miralbell, R
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
Background and purpose Variations in hip anatomy limit the femoral canal fit of standard uncemented hip stems. In addition, there are still issues with leg length discrepancy and offset reconstruction, potentially resulting in impingement, dislocation, and wear. Modular stems with different shapes for femoral canal fit and multiple neck options may improve the outcome and reduce complications. Patients and methods 173 patients (190 hips) received an uncemented THA with 1 of 2 different stem shapes for canal fit and a modular neck for stature-specific hip reconstruction. Median follow-up time was 9 (7–13) years. During the follow-up period, 20 patients died (22 hips) and 12 patients (13 hips) were lost to follow-up. 155 hips were available for evaluation, including clinical and radiological outcome. Results 1 stem was revised for a periprosthetic fracture following trauma; 10 cups and 2 modular necks were revised (1 for breakage and 1 during cup revision). At 10 years, stem survival was 100%, modular neck survival was 99% (CI: 95–100), and cup survival was 94% (CI: 87–97). No leg length discrepancies were measured in 96% of cases. Offset with anatomic lateralization was achieved in 98%. Median Harris hip score was 94 (47–100) and median Merle d'Aubigné score was 16 (10–18). Relevant radiolucent lines and osteolysis were not found. Interpretation The uncemented modular neck, dual-stem system used in this series allows accurate reconstruction of the joint by adapting the implant to the needs of the patient. This may improve the outcome of primary THA, which is supported by the results of this medium-term follow-up evaluation. PMID:20146639
Omlor, Georg W; Ullrich, Hannah; Krahmer, Knut; Jung, Alexander; Aldinger, Gunther
A randomized controlled trial was performed to examine the cost-effectiveness of external hip protectors in the prevention of hip fractures. Since the hip protectors were not effective in preventing hip fractures in our study, the main objective became to examine whether the use of hip protectors results in lower average costs per participant in the hip protector group as compared
Natasja M. van Schoor; Martine C. de Bruyne; Nicole van der Roer; Els Lommerse; Maurits W. van Tulder; Lex M. Bouter; P. T. A. M. Lips
We report a 75-year-old male patient with an aneurysm of the left femoral artery after cemented total hip arthroplasty. Two months after the operation, the patient showed a spherical resistance and pain in the left groin. Examination showed a big false aneurysm of the left femoral artery. After resection of the aneurysm, an endovascular stent graft vessel prosthesis was implanted.
D. Proschek; P. Proschek; K. Hochmuth; J. O. Balzer; M. G. Mack; T. J. Vogl
RationaleHypersensitivity reactions to metal implants have been reported mostly under the picture of local or systemic eczema or impaired wound and fracture healing. In addition, in arthroplasty non infectious complications like swelling, pain or loosening cannot be always explained by mechanical factors. We report on a patient with local seroma and loosening of his hip endoprosthesis, in whom patch testing
A. Schoberl; B. Summer; K. Jakob; S. Barnstorf; P. Thomas
BACKGROUND: Sufficient primary stability is a prerequisite for the clinical success of cementless implants. Therefore, it is important to have an estimation of the primary stability that can be achieved with new stem designs in a pre-clinical trial. Fast assessment of the primary stability is also useful in the preoperative planning of total hip replacements, and to an even larger
Maria E Zeman; Nicolas Sauwen; Luc Labey; Michiel Mulier; Georges Van der Perre; Siegfried VN Jaecques
Hip pain is a common and disabling condition that affects patients of all ages. The differential diagnosis of hip pain is broad, presenting a diagnostic challenge. Patients often express that their hip pain is localized to one of three anatomic regions: the anterior hip and groin, the posterior hip and buttock, or the lateral hip. Anterior hip and groin pain is commonly associated with intra-articular pathology, such as osteoarthritis and hip labral tears. Posterior hip pain is associated with piriformis syndrome, sacroiliac joint dysfunction, lumbar radiculopathy, and less commonly ischiofemoral impingement and vascular claudication. Lateral hip pain occurs with greater trochanteric pain syndrome. Clinical examination tests, although helpful, are not highly sensitive or specific for most diagnoses; however, a rational approach to the hip examination can be used. Radiography should be performed if acute fracture, dislocations, or stress fractures are suspected. Initial plain radiography of the hip should include an anteroposterior view of the pelvis and frog-leg lateral view of the symptomatic hip. Magnetic resonance imaging should be performed if the history and plain radiograph results are not diagnostic. Magnetic resonance imaging is valuable for the detection of occult traumatic fractures, stress fractures, and osteonecrosis of the femoral head. Magnetic resonance arthrography is the diagnostic test of choice for labral tears. PMID:24444505
Wilson, John J; Furukawa, Masaru
Total Hip Replacement is one of the most common operations performed in the developed world today. An increasingly ageing population means that the numbers of people undergoing this operation is set to rise. There are a numerous number of prosthesis on the market and it is often difficult to choose between them. It is therefore necessary to have a good understanding of the basic scientific principles in Total Hip Replacement and the evidence base underpinning them. This paper reviews the relevant anatomical and biomechanical principles in THA. It goes on to elaborate on the structural properties of materials used in modern implants and looks at the evidence base for different types of fixation including cemented and uncemented components. Modern bearing surfaces are discussed in addition to the scientific basis of various surface engineering modifications in THA prostheses. The basic science considerations in component alignment and abductor tension are also discussed. A brief discussion on modular and custom designs of THR is also included. This article reviews basic science concepts and the rationale underpinning the use of the femoral and acetabular component in total hip replacement. PMID:20582240
Mirza, Saqeb B; Dunlop, Douglas G; Panesar, Sukhmeet S; Naqvi, Syed G; Gangoo, Shafat; Salih, Saif
The development of a metal combination for modular hip systems was motivated by the following observations: (1) wear particles from polyethylene acetabular components can lead to a foreign body reaction and late aseptic loosening and (2) well designed all metal hip prostheses had very low wear rates, usually causing no osteolytic problems. The following challenges had to be met: (1) metal alloy with the maximum wear resistance; (2) the optimal clearance (difference in diameter) between 28-mm ball head and acetabular component; and (3) equipping modern, modular hip systems with metal combinations while maintaining compatibility with existing components. The realization of a metal combination consisted of the stable anchoring of a standard metal lining in a polyethylene insert that, combined, is intended to provide adequate load transfer and fit to either the bone cement bed or the titanium shell. The metal lining is manufactured from a carbide containing cobalt chromium molybdenum wrought alloy (Protasul-21WF). From 1988 to 1995, approximately 40,000 metal combinations (Metasul) were implanted. From these, 44 single components, with a maximum time in situ of 5.5 years, were retrieved and examined. The total linear wear rate averaged 2 to 5 micrometers per year per component after the initial conditioning phase. Under these conditions, particle induced late aseptic loosening is not to be expected. PMID:8769321
Schmidt, M; Weber, H; Schön, R
Ultra-high molecular weight polyethylene (UHMWPE) remains the gold standard acetabular bearing material for hip arthroplasty. Its successful performance has shown consistent results and survivorship in total hip replacement (THR) above 85% after 15 years, with different patients, surgeons, or designs. As THR results have been challenged by wear, oxidation, and liner fracture, relevant research on the material properties in the past decade has led to the development and clinical introduction of highly crosslinked polyethylenes (HXLPE). More stress on the bearing (more active, overweighted, younger patients), and more variability in the implantation technique in different small and large Hospitals may further compromise the clinical performance for many patients. The long-term in vivo performance of these materials remains to be proven. Clinical and retrieval studies after more than 5 years of in vivo use with HXLPE in THR are reviewed and consistently show a substantial decrease in wear rate. Moreover, a second generation of improved polyethylenes is backed by in vitro data and awaits more clinical experience to confirm the experimental improvements. Also, new antioxidant, free radical scavengers, candidates and the reinforcement of polyethylene through composites are currently under basic research. Oxidation of polyethylene is today significantly reduced by present formulations, and this forgiving, affordable, and wellknown material is still reliable to meet today’s higher requirements in total hip replacement. PMID:20111694
Gomez-Barrena, Enrique; Medel, Francisco; Puertolas, Jose Antonio
Metal-on-metal resurfacing arthroplasty of the hip has been used increasingly over the last 10 years in younger active patients. The dissolution of the metal wear particles results in measurable increases in cobalt and chromium ions in the serum and urine of patients with a metal-on-metal bearing. We measured the cobalt, chromium, and molybdenum ion levels in urine; serum; and breast milk in a young and active patient with a metal-on-metal hip prosthesis after a pathologic fracture of the femoral neck. Metal-on-metal hip prosthesis leads to increasing levels of molybdenum in breast milk in the short-term follow-up. There are no increasing levels of chromium and cobalt ions in breast milk. Besides the already known elevated concentrations in serum of chromium and cobalt after implantation of a metal-on-metal hip prosthesis, we found no increasing levels of chromium and cobalt in urine. PMID:22868068
Nelis, Raymond; de Waal Malefijt, Jan; Gosens, Taco
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.
This website includes an animation which illustrates the ion implant process. Objective: Name the three common dopants used in implantation processes and explain the process of generating an ion beam from source to wafer. You can find this animation under the heading "Process & Equipment III." This simulation is from Module 026 of the Process & Equipment III Cluster of the MATEC Module Library (MML). To view other clusters or for more information about the MML visit http://matec.org/ps/library3/process_I.shtmlKey
We are observing a selection of about 70 double-lined binaries (SB2s) with the T193/SOPHIE in order to improve their orbital elements. Our goal is to obtain the masses of the components with a 1 % accuracy when the astrometric observations of Gaia are available. After 6 semesters of observations, the two best observed stars are HIP 12081 and HIP 87895. These stars are used to verify that the 1 % accuracy could really be obtained at the end of the programme. The radial velocities of their components were derived using the TODMOR algorithm, and their orbital elements were calculated. It appears that the minimum masses of the components of HIP 12081 are already both obtained with an accuracy around 0.5 %. For HIP 87895, the relative precisions of the minimum masses of the primary and of the secondary component are 2.7 and 1.5 %, respectively, but they were obtained from only 9 spectra and they should be improved once more observations have been obtained. Ancient interferometric observations of HIP 87895 are also taken into account and the actual masses of the components are derived. Although these measurements are far from being as accurate as those expected from Gaia, the relative errors of the masses are only 2.6 and 1.5 % respectively. We thus conclude that our programme would lead to masses with the announced accuracy if the observations are continued.
Halbwachs, J.-L.; Arenou, F.; Guillout, P.; Pourbaix, D.; Tal-Or, L.; Famaey, B.; Lebreton, Y.; Mazeh, T.
In this paper, new bolaform cholesteryl imide derivatives with different spacers were designed and synthesized. Their gelation behaviors in 23 solvents were investigated, and some of them were found to be low molecular mass organic gelators. The experimental results indicated that these as-formed organogels can be regulated by changing the flexible/rigid segments in spacers and organic solvents. Suitable combination of flexible/rigid segments in molecular spacers in the present cholesteryl gelators is favorable for the gelation of organic solvents. Scanning electron microscopy and atomic force microscopy observations revealed that the gelator molecules self-assemble into different aggregates, from wrinkle and belt to fiber with the change of spacers and solvents. Spectral studies indicated that there existed different H-bond formations between imide groups and assembly modes, depending on the substituent spacers in molecular skeletons. The present work may give some insight into the design and character of new organogelators and soft materials with special molecular structures. PMID:24083361
With the extensive use of uncemented acetabular components in total hip arthroplasty, relocation of the hip center has become increasingly necessary to avoid bulk grafts and to promote contact between the porous prosthetic surface and bone. Compared with the anatomic hip center, superolateral relocation theoretically results in higher hip joint forces and has been shown in cemented acetabular components to
T. C. Doehring; H. E. Rubash; F. J. Shelley; L. J. Schwendeman; T. K. Donaldson; Y. A. Navalgund
Revision surgery is one of the most difficult reconstructive challenges facing orthopaedic surgeons; therefore, many new techniques and implants are needed to ensure that such patient can be successfully treated. We report a 66-year old female with a chronic dislocated bipolar hip prosthesis. She underwent a revision total hip arthroplasty combined with V-shaped subtrochanteric shortening osteotomy. This report demonstrates that V-shaped subtrochanteric shortening osteotomy can be used for revision surgery. Nevertheless, this technique is not suitable for all hip revisions, and the indications and various possible procedures and devices should be carefully considered to select the best treatment for each patient. We believe that the current report provides evidence supporting a new technical option for complex cases during revision THA. PMID:24683429
Sonohata, Motoki; Kitajima, Masaru; Kawano, Syunsuke; Honke, Hidefumi; Hotokebuchi, Takao; Mawatari, Masaaki
In a canine model, the fixation stability of a prosthesis and proximal bone graft composite were measured relative to the distal femur. One group had the prosthesis graft composite cemented into the distal femur. The second group had the prosthesis graft composite press fit into the distal femur for biologic ingrowth. Displacements of the proximal femoral grafts relative to the host bone in each group were measured after ex vivo (acute with graft) implantation and 4 months after implantation. A third group with no osteotomy (acute intact) simulated perfect graft to host bone union. Relative displacements representing 6 degrees freedom (translation and rotation) were calculated from the displacement values measured by 9 eddy current transducers. Measurements of displacement were used to test the hypothesis that distal press fit fixation equals distal cement fixation at 4 months after implantation. In all cases the measured translations and rotations of the graft to implant construct were small and of a magnitude that should encourage bone ingrowth (< 0.05 mm and < 0.1 degree, respectively). The stability of the press fit group at 4 months was not significantly different from the cemented group in axial and transverse displacement during axial and transverse loading, respectively. There was no difference in stabilities at 4 months between distal press fit and cemented fixation in hip replacements requiring a proximal femoral graft. PMID:9269179
Heiner, J P; Kohles, S S; Manley, P A; Vanderby, R; Markel, M D
In recent years, various uncemented proximal metaphyseal hip stems were introduced for younger patients as a bone preserving strategy. Initial osteodensitometric analyses of the surrounding bone of short stems indicate an increase of bone mass with secondary bone ingrowth fixation as a predictor of long-term survival of these types of implants. We report the outcome of 151 modular Metha short hip stem implants in 148 patients between March 2005 and October 2007. The mean follow-up was 5.8±0.7 years and the mean age of the patients was 55.7±9.8 years. Along with demographic data and co-morbidities, the Harris Hip Score (HHS), the Hip dysfunction and Osteoarthritis Outcome Score (HOOS), and also the results of a patient-administered questionnaire were recorded pre-operatively and at follow-up. The mean HHS increased from 46±17 pre-operatively to 90±5 the HOOS improved from 55±16 pre-operatively to 89±10 at the final follow-up. A total of three patients have been revised, two for subsidence with femoral revision and one for infection without femoral revision (Kaplan Meier survival estimate 98%). The radiological findings showed no radiolucent lines in any of the patients. The modular Metha short hip stem was implanted in younger patients, who reported an overall high level of satisfaction. The clinical and radiographic results give support to the principle of using short stems with metaphyseal anchorage. However, long-term results are necessary to confirm the success of this concept in the years to come. PMID:24416478
Thorey, Fritz; Hoefer, Claudia; Abdi-Tabari, Nima; Lerch, Matthias; Budde, Stefan; Windhagen, Henning
Modular femoral heads have been used successfully for many years in total hip arthroplasty. Few complications have been reported for the modular Morse taper connection between the femoral head and trunnion of the stem in metal-on-polyethylene bearings. Although there has always been some concern over the potential for fretting, corrosion, and generation of particulate debris at the modular junction, this was not considered a significant clinical problem. More recently, concern has increased because fretting and corrosive debris have resulted in rare cases of pain, adverse local tissue reaction, pseudotumor, and osteolysis. Larger femoral heads, which have gained popularity in total hip arthroplasty, are suspected to increase the potential for local and systemic complications of fretting, corrosion, and generation of metal ions because of greater torque at the modular junction. A less common complication is dissociation of the modular femoral heads. Morse taper dissociation has been reported in the literature, mainly in association with a traumatic event, such as closed reduction of a dislocation or fatigue fracture of the femoral neck of a prosthesis. This report describes 3 cases of spontaneous dissociation of the modular prosthetic femoral head from the trunnion of the same tapered titanium stem because of fretting and wear of the Morse taper in a metal-on-polyethylene bearing. Continued clinical and scientific research on Morse taper junctions is warranted to identify and prioritize implant and surgical factors that lead to this and other types of trunnion failure to minimize complications associated with Morse taper junctions as hip implants and surgical techniques continue to evolve. PMID:24972443
Talmo, Carl T; Sharp, Kinzie G; Malinowska, Magdalena; Bono, James V; Ward, Daniel M; LaReau, Justin
Hip fractures are one of the leading causes of morbidity and mortality among the elderly. Hip fracture is usually due to the combination of an acute event (a fall) with a chronic condition like osteoporosis. The literature is not very informative on the incidence of bilateral hip fracture. To investigate the consequences of the later fracture, we studied 31 patients
L. Galois; Y. Dausse; D. Mainard; J. P Delagoutte
Various approaches have been described for metal-on-metal hip resurfacing. We compared the posterolateral and direct lateral approaches for complications, pain, function, and implant survival in the short and medium term for two surgeons in a consecutive series of 790 patients (909 hips; July 1997 to July 2004) followed until July 2007. The direct lateral approach group included 135 resurfacing procedures and the posterolateral group included 774 procedures. There was no difference between the two groups for age or gender. The minimum followup for the anterolateral group was 2 years (mean, 5.1 years; range, 2.0–9.4 years) and for the posterolateral group 2 years (mean, 5.5 years; range, 2.0–9.6 years). There were no differences between the two approaches for complications, additional surgery, implant survival, or Oxford hip scores. The 8-year survival rate was 97.9% (95% confidence interval, 89.9–100) for the direct lateral approach and 97.2% (95% confidence interval, 93.9–99.3) for the posterolateral approach. This study indicates both approaches offer excellent pain reduction and return to function after Birmingham hip resurfacing with no difference in survival or in the incidence of complications. An 8-year survival rate of 97% can be achieved using either the posterolateral approach or the direct lateral approach. Level of Evidence: Level III, therapeutic study. See the Guidelines for authors for a complete description of levels of evidence. PMID:18224379
Revell, Matthew P.; Thomas, Andrew M.; Treacy, Ronan B.; Pynsent, Paul B.
Between November 1997 and December 2000 we performed 27 total hip replacements in 22 patients with high congenital dislocation of the hip using porous tantalum monoblock acetabular components implanted in the true acetabular bed. Clinical and radiological evaluation was performed at regular intervals for a mean of 10.2 years (8.5 to 12). The mean Harris Hip Score improved from 48.3 (15 to 65) pre-operatively to 89.5 (56 to 100) at the final follow-up. The mean Oxford Hip Score was 49.5 (35 to 59) pre-operatively and decreased to 21.2 (12 to 48) at one year and 15.2 (10 to 28) at final follow-up. Migration of the acetabular component was assessed with the EBRA software system. There was a mean migration of 0.68 mm (0.49 to 0.8) in the first year and a mean 0.89 mm (0.6 to 0.98) in the second year, after excluding one initial excessive migration. No revision was necessary for any reason, no acetabular component became loose, and no radiolucent lines were observed at the final follow-up. The porous tantalum monoblock acetabular component is an implant offering adequate initial stability in conjunction with a modulus of elasticity and porosity close to that of cancellous bone. It favours bone ingrowth, leading to good mid-term results. PMID:20435996
Macheras, G A; Kateros, K; Koutsostathis, S D; Tsakotos, G; Galanakos, S; Papadakis, S A
Summary Bacterial multidrug tolerance is largely responsible for the inability of antibiotics to eradicate infections and is caused by a small population of dormant bacteria called persisters. HipA is a critical Escherichia coli persistence factor that is normally neutralized by HipB, a transcription repressor, which also regulates hipBA expression. Here we report multiple structures of HipA and a HipA-HipB-DNA complex. HipA has a eukaryotic Ser/Thr kinase-like fold and can phosphorylate the translation factor, EF-Tu, suggesting a persistence mechanism via cell stasis. The HipA-HipB-DNA structure reveals the HipB-operator binding mechanism, ~70° DNA bending and unexpected HipA-DNA contacts. Dimeric HipB interacts with two HipA molecules to inhibit its kinase activity through sequestration and conformational inactivation. Combined, these studies suggest mechanisms for HipA-mediated persistence and its neutralization by HipB. PMID:19150849
Schumacher, Maria A.; Piro, Kevin M.; Xu, Weijun; Hansen, Sonja; Lewis, Kim; Brennan, Richard G.
Administration of low-molecular-weight heparin prophylaxis in elective hip implant patients commonly begins 12 h preoperatively in European practices to optimize effectiveness, and 12 to 24 h postoperatively in North American practices to optimize safety. A meta-analysis comparing these two treatment regimes revealed that preoperative initiation demonstrated greater efficacy and superior safety for patients (10.0% rate of total deep-vein thrombosis vs.
Russell D. Hull; Graham F. Pineo; Susan MacIsaac
Periprosthetic bone loss is an important factor that limits implant survival after total hip arthroplasty (THA). In a randomized trial we previously reported that pamidronate therapy prevented periprosthetic bone loss and decreased urinary excretion of N-telopeptide collagen cross-links over the first 6 months after THA, but had no apparent effect on free deoxypyridinoline excretion (J Bone Miner Res 2001; 16:556–564).
J. Mark Wilkinson; Brendan Jackson; Richard Eastell
Polymeric wear debris produced by articulation of the femoral head against the ultra-high-molecular-weight polyethylene (UHMWPE) socket of a total hip replacement has been implicated as the main cause of osteolysis and subsequent failure of these implants. Potential solutions to this problem are to employ hard-bearing surface combinations such as metal-on-metal or ceramic-on-ceramic prostheses. The aim of this study was to
S. C Scholes; A Unsworth; R. M Hall; R Scott
A filter holder assembly is provided that utilizes a fail-safe regenerator unit with an annular spacer ring having an extended metal collar for containment and positioning of a compliant ceramic gasket used in the assembly. The filter holder assembly is disclosed for use with advanced composite, filament wound, and metal candle filters.
Alvin, Mary Anne (Pittsburgh, PA); Bruck, Gerald J. (Murrysville, PA)
Closely machined steel ring having narrow sealing lands on both faces and a thin coating of a commercially available halocarbon polymer combines the functions of a spacer and static seal ring or gasket having a minimum of potential leak paths. The device is effective over a wide range of temperatures down to minus 423 deg F and at pressure up to 180 psig.
Jones, F. B.
Background and purpose Hip resurfacing (HRS) procedures have gained increasing popularity for younger, higher-demand patients with degenerative hip pathologies. However, with concerns regarding revision rates and possible adverse metal hypersensitivity reactions with metal-on-metal articulations, some authors have questioned the hypothesized superiority of hip resurfacing over total hip arthroplasty (THA). In this meta-analysis, we compared the clinical and radiological outcomes and complication rates of these 2 procedures. Methods A systematic review was undertaken of all published (Medline, CINAHL, AMED, EMBASE) and unpublished or gray literature research databases up to January 2010. Clinical and radiological outcomes as well as complications of HRS were compared to those of THA using risk ratio, mean difference, and standardized mean difference statistics. Studies were critically appraised using the CASP appraisal tool. Results 46 studies were identified from 1,124 citations. These included 3,799 HRSs and 3,282 THAs. On meta-analysis, functional outcomes for subjects following HRS were better than or the same as for subjects with a THA, but there were statistically significantly greater incidences of heterotopic ossification, aseptic loosening, and revision surgery with HRS compared to THA. The evidence base showed a number of methodological inadequacies such as the limited use of power calculations and poor or absent blinding of both patients and assessors, possibly giving rise to assessor bias. Interpretation On the basis of the current evidence base, HRS may have better functional outcomes than THA, but the increased risks of heterotopic ossification, aseptic loosening, and revision surgery following HRS indicate that THA is superior in terms of implant survival. PMID:21067432
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
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.
Metal on metal hip joint prostheses are now commonly implanted in patients with hip problems. Although hip replacements largely go ahead problem free, some complications can arise such as infection immediately after surgery and aseptic necrosis caused by vascular complications due to surgery. A recent observation that has been made at Manchester is that some Cobalt Chromium (CoCr) implants are causing chronic pain, with the source being as yet unidentified. This form of replacement failure is independent of surgeon or hospital and so some underlying body/implant interface process is thought to be the problem. When the synovial fluid from a failed joint is examined particles of metal (wear debris) can be found. Transmission Electron Microscopy (TEM) has been used to look at fixed and sectioned samples of the synovial fluid and this has identified fine (< 100 nm) metal and metal oxide particles within the fluid. TEM EDX and Electron Energy Loss Spectroscopy (EELS) have been employed to examine the composition of the particles, showing them to be chromium rich. This gives rise to concern that the failure mechanism may be associated with the debris.
Ward, M. B.; Brown, A. P.; Cox, A.; Curry, A.; Denton, J.
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
A 29 year old female recreational runner presented with two separate episodes of hip pain. The first, affecting the right hip was an uncommon cause of hip pain--an osteoid osteoma. The second, affecting the left hip was a more predictable cause of hip pain in a runner--a femoral stress fracture. Management of the subsequent stress fracture enabled more detailed and prolonged observation of the natural history and clinical course of the osteoid osteoma. The presentation and management of each of the conditions is discussed. PMID:8776213
Batt, M E; Timmerman, L A
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
Hip dislocation is a major short-term complication after total hip arthroplasty (THA). One factor thought to reduce the risk for dislocation is head size. We constructed subject-specific computer models to study the effect of head size on risk for postoperative dislocation. Femoral and acetabular geometry was constructed after segmenting CT scans of nine hips. CAD models of THA components with four head diameters (28, 32, 36, and 44?mm) were virtually implanted. Hip capsular ligaments were simulated using rigid-body ellipsoids connected by non-linear springs. Posterior dislocation was simulated during a rise from a low chair; anterior dislocation was simulated during a pivot activity. Intraoperative stability tests were simulated for anterior or posterior dislocation. While rising from a low chair (posterior dislocation) and during the pivot activity (anterior dislocation), increasing head size significantly increased hip flexion angle at dislocation and generated higher dislocation moments. Larger heads reduced the risk for dislocation. Intraoperative stability tests detected the relative increased resistance to dislocation despite differences in the absolute magnitude of moments. This model can be useful preclinical tool for assessing design changes, the effect of component placement, and the activity-based risk for dislocation. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:1525-1531, 2014. PMID:24961686
Bunn, Adam; Colwell, Clifford W; D'Lima, Darryl D
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. PMID:22144743
Rai, Anil Kumar; Singh, Saurabh; Kumaraswamy, Vinay; Khare, GN; Yadav, Vinit; Agarwal, Rakesh
Subdermal contraceptive implants offer women long-acting, controlled release of progestins. Over the past 20 years, they have\\u000a been approved in more than 60 countries and used by more than 11 million women worldwide. Their high efficacy along with ease\\u000a of use make them a good contraceptive option for women who require progestin-only methods because they should not use estrogen,\\u000a teens
Philip D. Darney
This Notice of Construction (NOC) presents the proposed plans to remove the spacers from the silos located at the 100-N Area. September 30, 1995 is the milestone established by the Washington State Department of Ecology, the US Environmental Protection Ag...
This paper presents an investigation of the compression properties and air permeability of weft?knitted spacer fabrics. Twenty spacer fabrics were knitted on a computerized flat knitting machine with different weft knit patterns, spacer yarns, and loop lengths (stitch cam settings). Their compression property and air permeability were tested with the Kawabata Evaluation System for Fabrics (KES?F). The influences of different
Yanping Liu; Hong Hu
The lateral aspect of the hip is composed of a complex array of osseous and soft tissue structures. Both common and uncommon clinical entities are encountered in the lateral hip. This article briefly introduces fundamental imaging anatomy and the functional roles of different osseous and soft tissue structures in the lateral aspect of the hip, followed by a discussion of relevant imaging findings of lateral hip pathology. Greater trochanteric pain syndrome is frequently encountered in patients with lateral hip pain and encompasses a spectrum of soft tissue abnormalities including trochanteric and subgluteal bursitis, and tendinopathy or tears of the gluteal tendons. In addition, different types of injuries to the gluteal myotendinous unit and injuries to the indirect head of the rectus femoris, proximal iliotibial band, and the lateral joint capsular ligaments can present with lateral hip pain. Some of the less common soft tissue abnormalities of the lateral hip include Morel-Lavallée lesion and meralgia paresthetica. PMID:23787984
Pan, Judong; Bredella, Miriam A
Background In 2005, we reported removal of functional restriction after primary THA performed through the anterolateral approach did not increase the incidence of dislocation. Questions/purposes To develop a current practice guideline, we evaluated the incidence of early dislocation after primary THA after implementation of a no-restriction protocol. Methods Between January 2005 and December 2007, 2532 patients (2764 hips; 1541 women, 1223 men; mean age, 63.2 years [28–98 years]) underwent primary THA at our institution. Bilateral THA was performed in 232 patients (464 hips). The direct anterior or anterolateral approach was used in all patients. Femoral head size was 28, 32, or 36 mm. Patients were given no traditional functional restrictions postoperatively, such as use of elevated seats, abduction pillows, and restriction from driving. All patients received standard care at the judgment of the attending surgeon. One hundred forty-six patients missed followup appointments despite efforts to be contacted by telephone. The remaining 2386 of 2532 patients (94%) had a minimum followup of 6 months (mean, 14.2 months; range, 6–34 months). Results Four known dislocations occurred in the followed cohort of 2386 patients with 2612 hips (0.15%) at a mean of 5 days (3–12 days) postoperatively, none related to high-impact trauma. One dislocation occurred in a patient with a history of developmental dysplasia of the hip, two dislocations occurred while at the toilet (one with a previous hip fracture treated with a modular system), and one dislocation was idiopathic. Conclusions We confirmed a low incidence of dislocation after primary THA in the absence of early postoperative restrictions. We conclude a no-restriction protocol does not increase the incidence of early dislocation after primary THA. Level of Evidence Level II, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence. PMID:21076896
Restrepo, Camilo; Mortazavi, S. M. Javad; Brothers, Justin; Parvizi, Javad
The Dynesys System for stabilizing the lumbar spine was first surgically implanted in Europe in 1994. In 2003, a prospective, randomized, investigational device exemption clinical trial of the system for non-fusion dynamic stabilization began. Polycarbonate urethane (PCU) and polyethylene terephthalate (PET) components explanted from four patients who had participated in the study were analyzed for biostability. Components had been implanted 9-19 months. The explanted components were visually inspected and digitally photographed. Scanning electron microscopy was used to analyze the surface of the spacers. The chemical and molecular properties of the retrieved spacers and cords were quantitatively compared with lot-matched, shelf-aged, components that had not been implanted using attenuated total reflection Fourier transform infrared (FTIR) and gel permeation chromatography (GPC). FTIR analyses suggested that the explanted spacers exhibited slight surface chemical changes but were chemically unchanged below the surface and in the center. New peaks that could be attributed to biodegradation of PCU were not observed. The spectral analyses for the cords revealed that the PET cords were chemically unchanged at both the surface and the interior. Peaks associated with the PET biodegradation were not detected. GPC results did not identify changes to the distributions of molecular weights that might be attributed to biodegradation of either PCU spacers or PET cords. The explanted condition of the retrieved components demonstrated the biostability of both PCU spacers and PET cords that had been in vivo for up to 19 months. PMID:21538208
Shen, Ming; Zhang, Kai; Koettig, Petra; Welch, William C; Dawson, John M
Art has a way of helping students better understand and appreciate the world around them, particularly the things that are most important to them. Hip hop is one of those generational genres that capture the attention of young students like few other things do. Drawing on this genre to get students to create art is an excellent way to demonstrate…
Talley, Clarence, Sr.
Web services designed for human users are being abused by computer programs (bots). The bots steal thousands of free email accounts in a minute, participate in online polls to skew results, and irritate people in chat rooms. These real-world issues have recently generated a new research area called Human Interactive Proofs (HIP), whose goal is to defend web services from
Zhenqiu Zhang; Yong Rui; Thomas S. Huang; Cem Paya
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
Since polyethylene is one of the most frequently used biomaterials as a liner in total hip arthroplasty, strong efforts have been made to improve design and material properties over the last 50 years. Antioxidants seems to be a promising alternative to further increase durability and reduce polyethylene wear in long term. As of yet, only in vitro results are available. While they are promising, there is yet no clinical evidence that the new material shows these advantages in vivo. To answer the question if vitamin-E enhanced ultra-high molecular weight polyethylene (UHMWPE) is able to improve long-term survivorship of cementless total hip arthroplasty we initiated a randomized long-term multicenter trial. Designed as a superiority study, the oxidation index assessed in retrieval analyses of explanted liners was chosen as primary parameter. Radiographic results (wear rate, osteolysis, radiolucency) and functional outcome (Harris Hip Scores, University of California-Los Angeles, Hip Disability and Osteoarthritis Outcome Score, Visual Analogue Scale) will serve as secondary parameters. Patients with the indication for a cementless total hip arthroplasty will be asked to participate in the study and will be randomized to either receive a standard hip replacement with a highly cross-linked UHMWPE-X liner or a highly cross-linked vitamin-E supplemented UHMWPE-XE liner. The follow-up will be 15 years, with evaluation after 5, 10 and 15 years. The controlled randomized study has been designed to determine if Vitamin-E supplemented highly cross-linked polyethylene liners are superior to standard XLPE liners in cementless total hip arthroplasty. While several studies have been started to evaluate the influence of vitamin-E, most of them evaluate wear rates and functional results. The approach used for this multicenter study, to analyze the oxidation status of retrieved implants, should make it possible to directly evaluate the ageing process and development of the implant material itself over a time period of 15 years. PMID:25002933
Jäger, Marcus; van Wasen, Andrea; Warwas, Sebastian; Landgraeber, Stefan; Haversath, Marcel; Group, Vitas
Insertion of an interspinous devices has became a common procedure for the treatment of different clinical picture of degenerative spinal disease. We present our experience in 1,575 patients with the use of two different interspinous spacers: Device for Intervertebral Assisted Motion (DIAM) and Aperius PercLID system. From 2000 through 2008, 1,315 consecutive patients underwent DIAM implantation and 260 had an Aperius PercLID procedure. The main surgical indications included: degenerative disc disease (478 patients), canal and/or foraminal stenosis (347 patients), disc herniation (283 patients), black disc and facet syndrome (143) and topping-off (64 patients). 1,100 patients underwent a single level implant and 475 had a multiple level implant. Mean operating time was 35 min for DIAM and 7 min for Aperius. Complications were detected in 20 patients (10 cases of infections, 10 fractures of the posterior spinous processes). 40 patients were subsequently treated with posterior arthrodesis (n = 30) or total disc replacement (n = 10). Patient's postoperative clinical status was rated according to the modified Macnab criteria: symptoms resolution or improvement was achieved in 1,505 patients; and unchanged or unsatisfactory results in 70. Both techniques are safe, simple and less technically demanding. These approaches appear to be an effective alternative in selected cases, although conventional posterior lumbar decompression and fusion still may be required. PMID:21409561
Fabrizi, Antonio P; Maina, Raffaella; Schiabello, Luigi
Management of geriatric hip fractures in a protocol-driven center can improve outcomes and reduce costs. Nonetheless, this approach has not spread as broadly as the effectiveness data would imply. One possible explanation is that operating such a center is not perceived as financially worthwhile. To assess the economic viability of dedicated hip fracture centers, the authors built a financial model to estimate profit as a function of costs, reimbursement, and patient volume in 3 settings: an average US hip fracture program, a highly efficient center, and an academic hospital without a specific hip fracture program. Results were tested with sensitivity analysis. A local market analysis was conducted to assess the feasibility of supporting profitable hip fracture centers. The results demonstrate that hip fracture treatment only becomes profitable when the annual caseload exceeds approximately 72, assuming costs characteristic of a typical US hip fracture program. The threshold of profitability is 49 cases per year for high-efficiency hip fracture centers and 151 for the urban academic hospital under review. The largest determinant of profit is reimbursement, followed by costs and volume. In the authors’ home market, 168 hospitals offer hip fracture care, yet 85% fall below the 72-case threshold. Hip fracture centers can be highly profitable through low costs and, especially, high revenues. However, most hospitals likely lose money by offering hip fracture care due to inadequate volume. Thus, both large and small facilities would benefit financially from the consolidation of hip fracture care at dedicated hip fracture centers. Typical US cities have adequate volume to support several such centers. PMID:24579222
Clement, R Carter; Ahn, Jaimo; Mehta, Samir; Bernstein, Joseph
Flow rates and pressure thermal profiles for two phase choked flows of fluid nitrogen were studied theoretically and experimentally in a four sequential orifice configuration. Both theory and experimental evidence demonstrate that heat addition in the first spacer-reservoir adjacent to the inlet orifice is most effective in reducing the flow rate and that heat addition in the last spacer-reservoir is least effective. The flows are choked at the exit orifice for large spacings and at the inlet orifice for small spacings. The moderate addition of heat available for this experiment did not materially alter this result for large spacings; however, significant heat addition for the small spacings tended to shift the choke point to the exit orifice. Nitrogen is used as the working fluid over a range of states from liquid to gas with a reduced inlet stagnation pressure range to P sub r, o = 2.
Hendricks, R. C.; Stetz, T. T.
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.
Abstract: Background: Hip fracture is the most serious complication of osteoporosis and imposes a significant financial burden on countries' economy. This study aimed to assess the hospitalization costs and length of stay associated with osteoporosis hip fractures and identify the major cost components in a referral hospital in Kermanshah city, Iran. Methods: In a prospective study, from May 21 2007 to May 21 2008, all patients with osteoporotic hip fracture admitted to a referral hospital for operation were recruited as the study sample. For each patient, information such as age, gender, length of stay (LOS) in hospital and intensive care unit (ICU), medical and diagnostic procedures and cost of surgery and implant were collected both through interview with the patient or a family member and the patients’ hospital records. Results: A total of 103 patients (56 men and 47 women) were studied. The average hospital length of stay (LOS) for the patients was 9.7 days, ranging from 5 to 38 days. The average total hospitalization costs was 7,208,588 IRR (US$774). The main components of the costs were ward stay (16.3%), operative (54.6%), implant (26%) and medical and diagnostic procedures (3.1%). Conclusions: The results of this study demonstrate that the hospital resource burden associated with osteoporotic hip fractures in Iran is substantial and expected to rise with the projected increase of life expectancy and the number of elderly in Iran. Estimating the economic burden of osteoporotic hip fractures provide information that can be of importance in the planning and design of preventive strategies. PMID:23793366
Saeb, Morteza; Beyranvand, Mandana; Basiri, Zahra; Haghparast-Bidgoli, Hassan
In case of implant associated infection, implant preservation is associated with high failure rates. Therefore, a removal or exchange of the implant is most often mandatory for treatment success. Alternatively, under certain conditions, local antibiotic delivery can be applied - preserving the implant, using for example calcium sulphate as a resorbable carrier. In this work, third-body wear on total hip prostheses caused by calcium sulphate particles was tested in a hip simulator. Inlays made of ultra-high-molecular-weight polyethylene (UHMWPE) and cross-linked polyethylene (XLPE) against 28 mm CoCrMo heads and 36 mm alumina pairings were tested in triplicate, both with and without calcium sulphate particles in the test liquid. Neither the alumina articulations nor the CoCrMo heads were affected by the calcium sulphate particles since calcium sulphate is a relatively soft material. The polyethylene inlays showed 39-89 % higher wear during exposure compared to references, but wear returned to normal when no more particles were added. Thus, calcium sulphate might be used as antibiotic carrier even in the presence of total hip prostheses without fearing excessive third-body wear. PMID:25340804
Heuberger, R; Wahl, P; Krieg, J; Gautier, E
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.
Background Total hip replacement is considered the best option for treatment of displaced intracapsular fractures of the femoral neck (FFN). The size of the femoral head is an important factor that influences the outcome of a total hip arthroplasty (THA): implants with a 28 mm femoral head are more prone to dislocate than implants with a 32 mm head. Obviously, a large head coupled to a polyethylene inlay can lead to more wear, osteolysis and failure of the implant. Ceramic induces less friction and minimal wear even with larger heads. Methods A total of 35 THAs were performed for displaced intracapsular FFN, using a 32 mm alumina-alumina coupling. Results At a mean follow-up of 80 months, 33 have been clinically and radiologically reviewed. None of the implants needed revision for any reason, none of the cups were considered to have failed, no dislocations nor breakage of the ceramic components were recorded. One anatomic cementless stem was radiologically loose. Conclusions On the basis of our experience, we suggest that ceramic-on-ceramic coupling offers minimal friction and wear even with large heads. PMID:21284879
We retrospectively reviewed 68 hips in 62 patients with acetabular dysplasia who underwent curved periacetabular osteotomy. Among the 68 hips, 33 had acetabular retroversion (retroversion group) and 35 had anteversion (control group) preoperatively. All hips were evaluated according to the Harris hip score. Radiographic evaluations of acetabular retroversion and posterior wall deficiency were based on the cross-over sign and posterior wall sign, respectively. The clinical scores of the two groups at the final follow-up were similar. In the retroversion group, 12 hips had anteverted acetabulum postoperatively. The posterior wall sign disappeared in these hips, but remained in 21 hips with retroverted acetabulum postoperatively. Among the 21 hips with retroverted acetabulum, posterior osteoarthritis of the hip developed postoperatively in five hips. When performing corrective osteotomy for a dysplastic hip with acetabular retroversion, it is important to correct the acetabular retroversion to prevent posterior osteoarthritis of the hip due to posterior wall deficiency. PMID:18157533
Naito, Masatoshi; Shiramizu, Kei; Shinoda, Tsuyoshi
This case study presents a subject with a fused hip converted to total hip arthroplasty. Kinematic gait analysis was conducted on 3 occasions, presurgery, 4 months postsurgery, and 2.5 years postsurgery. Presurgery data showed decreased cadence and shorter step length; sound limb possessed increased hip, knee range of motion (ROM), and increased knee flexion during stance; the affected limb had
Stephanie J. Bonin; Moataz A. Eltoukhy; W. Andrew Hodge; Shihab S. Asfour
Summary To examine the influence of intra- and post-operative blood loss and operative trauma on erythropoietin (EPO) production we studied patients undergoing endoprothetic surgery of the hip. Immunoreactive plasma EPO was determined in ten patients (seven male, three female, aged 39–68 years), undergoing surgery for hip arthroplasty (n=8) or revision hip arthroplasty (n=2). EPO levels had already been determined during
A. Lorentz; K.-U. Eckardt; P. M. Osswald; C. Kruse
The hip labrum has many functions, including shock absorption, joint lubrication, pressure distribution, and aiding in stability,\\u000a with damage to the labrum associated with osteoarthritis. The etiology of labral tears includes trauma, femoroacetabular impingement\\u000a (FAI), capsular laxity\\/hip hypermobility, dysplasia, and degeneration. Labral tears present with anterior hip or groin pain,\\u000a and less commonly buttock pain. Frequently, there are also mechanical
Megan M. Groh; Joseph Herrera
The occurrence of pseudotumours following metal-on-metal hip resurfacing arthroplasty (MoMHRA) has been associated with high serum metal ion levels and consequently higher than normal bearing wear. Measuring ground reaction force is a simple method of collecting information on joint loading during a sit-to-stand (STS). We investigated vertical ground reaction force (VGRF) asymmetry during sit-to-stand for 12 MoMHRA patients with known serum metal ion levels. Asymmetry was assessed using two methods: a ratio of VGRF for implanted/unimplanted side and an absolute symmetry index (ASI). It was found that subjects with high serum metal ion levels preferentially loaded their implanted sides. The difference between the two groups was most apparent during the first 22% of STS. VGRF ratio showed significant and strong correlation with serum metal ion levels (Spearman's rho = 0.8, p = 0.003). These results suggest that individual activity patterns play a role in the wear of MoMHRA and preferential loading of an implanted limb during the initiation of motion may increase the wear of metal-on-metal hip replacements. PMID:24474415
Mellon, Stephen; Grammatopoulos, George; Pandit, Hemant; Murray, David W; Gill, Harinderjit S
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. PMID:18412506
Zant, N. P.; Heaton-Adegbile, P.; Hussell, G. J.; Tong, J.
We present a potential indication of a short-stemmed femoral component in a patient with multiple comorbidities presenting with hip posttraumatic osteoarthritis and a long dynamic condylar screw osteosynthesis plate. Removal of the plate and implantation of a long stem would have been related to a much longer operative time and potential local or systemic complications.
Buttaro, Martin; Piuzzi, Nicolas; Comba, Fernando; Zanotti, Gerardo; Piccaluga, Francisco
Summary Dual X-ray absorptiometry (DXA) instruments are now able to evaluate bone mineral density (BMD) of bone surrounding metal implants. The assessment of BMD around prosthetic components could provide additional information for the follow-up of total hip arthroplasty (THA). In this study, we evaluated the potential application of DXA in the field of THA. BMD was measured in the proximal
Carlo Trevisan; Marco Bigoni; Roberto Cherubini; Peter Steiger; Gianni Randelli; Sergio Ortolani
Total hip joint replacement offers dramatic improvement in the quality of life but deep infection is the most feared complication of this procedure. The infection threatens the function of the joint, the preservation of the limb, and occasionally even the life of the patient. For the surgeon it is a disastrous anticlimax, which follows a procedure that may have given the patient freedom from pain and increased mobility. PMID:15239869
Kaltsas, Dimitris S.
The current authors review clinical and retrieval experiences with hemispheric monolithic alumina ceramic sockets (Group 1), implanted between 1976 and 1979, and similar modular titanium sockets with alumina ceramic inlays (Group 2), implanted between 1990 and 1995. Both cementless sockets articulated with alumina ceramic femoral ball heads for total hip joint replacements. Clinical followup of patients with hemispheric monolithic alumina ceramic sockets (Group 1, 138 sockets) resulted in a total failure rate of 19.6% after 5 to 20 years. Radiologic analysis of eight stable sockets showed migration of 0.2 mm to 2.89 mm, but in four sockets at risk for late aseptic failure after an average followup of 12.5 years as much as 13.4 mm of migration was seen. Histologic evaluation revealed pseudosynovial membranes as thick as 1 mm with fine birefringent wear particles within mononuclear macrophages around two stable retrieved sockets. The membranes around four loose sockets were 6 to 10 mm thick and also heavily loaded with larger alumina wear particles. After 7 years followup clinical analysis of patients with modular titanium sockets with alumina ceramic inlays (Group 2, 30 sockets) resulted in four revisions, compared with one revision of 50 identical sockets (control group) with polyethylene instead of alumina ceramic inlays. Wear particle analyses in scanning electron microscopy showed significantly more particles (x 10(9) +/- standard deviation/g dry tissue) from the control group (4.26+/-6.38), compared with alumina ceramic bearings of Group 1 (0.70+/-0.79), and of Group 2 (1.62+/-2.13). The alumina particle sizes ranged between 0.13 and 78.38 microm. The mean annual linear wear of 38.8 microm was calculated for the bearings in Group 1, and of 26.94 microm for bearings in Group 2. These results support the good tribologic and biologic performance of alumina ceramic bearings for total hip arthroplasty. PMID:11039796
Boehler, M; Plenk, H; Salzer, M
Summary The increasing use of orthopedic implants and, in particular, of hip and knee joint replacements for young and active patients, has stimulated interest and concern regarding the chronic, long-term effects of the materials used. This review focuses on the current knowledge of the adverse biologic reactions to metal particles released from orthopaedic implants in vivo and in vitro. More specifically, the purpose of this article is to provide an overview of the current literature about the adverse effects of metal particles on bone cells and peri-implant bone. PMID:23858309
Sansone, Valerio; Pagani, Davide; Melato, Marco
The demand for total hip replacement (THR) surgery is increasing in the younger population due to faster rehabilitation and more complete restoration of function. Up to 2009, metal-on-metal (MoM) hip joint bearings were a popular choice due to their design flexibility, post-operative stability and relatively low wear rates. The main wear mechanisms that occur along the bearing surface of MoM joints are tribochemical reactions that deposit a mixture of wear debris, metal ions and organic matrix of decomposed proteins known as a tribolayer. No in-depth electrochemical studies have been reported on the structure and characteristics of this tribolayer or about the parameters involved in its formation. In this study, we conducted an electrochemical investigation of different surfaces (bulk-like: control, nano-crystalline: new implant and tribolayer surface: retrieved implant) made out of two commonly used hip CoCrMo alloys (high-carbon and low-carbon). As per ASTM standard, cyclic polarization tests and electrochemical impedance spectroscopy tests were conducted. The results obtained from electrochemical parameters for different surfaces clearly indicated a reduction in corrosion for the tribolayer surface (Icorr: 0.76?A/cm(2)). Further, polarization resistance (Rp:2.39±0.60M?/cm(2)) and capacitance (Cdl:15.20±0.75?F/cm(2)) indicated variation in corrosion kinetics for the tribolayer surface, that attributed to its structure and stability in a simulated body environment. PMID:24099949
Mathew, M T; Nagelli, C; Pourzal, R; Fischer, A; Laurent, M P; Jacobs, J J; Wimmer, M A
Adverse local tissue reactions occurring in metal-on-metal total hip arthroplasty (MoM THA) could potentially lead to secondary failure modes such as dislocation or infection. The authors report a series of 124 patients treated with MoM hip arthroplasty between 2006 and 2010 with a minimum follow-up of 3 years. Eight hips presented with acute delayed or late periprosthetic joint infection (PJI) (defined as an infection occurring after 3 months in an otherwise well functioning implant). The rate of infection observed was higher than expected, almost 4 times higher (5.6%) compared to previous historical cohorts from our institution (1.3%). This high risk of infection in patients with DePuy ASR implants requires further study but we theorize that the increased prevalence of infection could be due to a combination of particulate debris, molecular (rather than particulate) effects of Co and Cr ions on soft tissues, and/or products of corrosion that may change the local environment predisposing to infection. PMID:24851788
Prieto, Hernan A; Berbari, Elie F; Sierra, Rafael J
Ultra-high molecular weight polyethylene acetabular cups of 5 different total hip systems (Müller, Mallory-Head, Lubinus, P.C.A. and Charnley-Elite) were worn on a new 5-station hip joint simulator. The cups articulated against modular metallic (stainless steel in Müller and Charnley-Elite, ion-implanted Ti-6Al-4V in Mallory-Head, and Co-Cr-Mo in Lubinus and P.C.A.) and modular alumina ceramic femoral heads for 3 million walking cycles. The mean wear rate of cups against alumina heads (range 0-5.7 mg/10(6) cycles, corresponding to 0-0.008 mm/year) was usually lower than against metallic heads (range 3.9-178 mg/10(6) cycles, corresponding to 0.005-0.24 mm/year). In the metal-head prostheses, the mean wear rate was highest against stainless steel heads, and lowest against ion-implanted Ti-6Al-4V heads. As the wear rates are compared with published clinical observations, it can be concluded that the hip joint simulator is capable of producing realistic wear rates; it is a useful instrument in the study of the wear behavior of new designs, materials, surface treatments and coatings prior to clinical trials. However, the taper-fit attachment of modular heads proved problematical, showing corrosion and wear at the conical head-spigot interface. PMID:8213114
Saikko, V O; Paavolainen, P O; Slätis, P
Total hip arthroplasties (THA) can be performed with cemented and uncemented femoral components. Aseptic loosening of the joint replacement still illustrates a problem for both implantation techniques. This loosening can be caused, among other factors, by resorption of the bone surrounding the implant due to stress shielding. In order to analyse the absolute influence of the implantation technique on the bone degeneration in the periprosthetic femur, the strain adaptive bone remodelling after THA was investigated in a three-dimensional finite element (FE) simulation of a femur provided with a cemented and uncemented BICONTACT (Aesculap, Tuttlingen, Germany) femoral component. For this, a bone density evolution theory was implemented in the FE code MSC.MARC. In these static FE simulations, the muscle and hip resultant forces represent the maximum loading situation in the normal walking cycle. To describe the mechanical properties of the bone, an isotropic material law dependent upon density was used. The situation directly after implantation without any bone ingrowth was simulated. The cemented femoral component was bonded to the bone by a homogenous cement mantle. The numerical results show that proximally, the bone resorption areas surrounding the BICONTACT stem are heavily dependent upon anchoring technique. Furthermore, no significant bone remodelling is calculated in the distal periprosthetic femur in both models. PMID:18376011
Behrens, B-A; Bouguecha, A; Nolte, I; Meyer-Lindenberg, A; Stukenborg-Colsman, C; Pressel, T
This case study presents a subject with a fused hip converted to total hip arthroplasty. Kinematic gait analysis was conducted on 3 occasions, presurgery, 4 months postsurgery, and 2.5 years postsurgery. Presurgery data showed decreased cadence and shorter step length; sound limb possessed increased hip, knee range of motion (ROM), and increased knee flexion during stance; the affected limb had minimal hip motion and normal knee ROM with abnormal pattern. At 4 months postsurgery, the sound limb showed decreased step length, whereas the affected limb showed increased knee extension during stance and increased hip ROM. Data obtained at 2.5 years postsurgery indicated decreased cadence and speed and increased ROM in both limbs. The total hip arthroplasty had provided relief of chronic back and affected hip pain and improved mobility. Gait-specific training is recommended. PMID:21944370
Bonin, Stephanie J; Eltoukhy, Moataz A; Hodge, W Andrew; Asfour, Shihab S
Background In 2005, we reported removal of functional restriction after primary THA performed through the anterolateral approach did\\u000a not increase the incidence of dislocation.\\u000a \\u000a \\u000a \\u000a \\u000a Questions\\/purposes To develop a current practice guideline, we evaluated the incidence of early dislocation after primary THA after implementation\\u000a of a no-restriction protocol.\\u000a \\u000a \\u000a \\u000a \\u000a Methods Between January 2005 and December 2007, 2532 patients (2764 hips; 1541 women, 1223 men; mean
Camilo Restrepo; S. M. Javad Mortazavi; Justin Brothers; Javad Parvizi; Richard H. Rothman
A single step is relied on in the canning process for hot isostatic pressing (HIP) metallurgy composites. The composites are made from arc sprayed and plasma sprayed monotape. The HIP can is of compatible refractory metal and is sealed at high vacuum and temperature. This eliminates outgassing during hot isostatic pressing.
Juhas, John J. (inventor)
HIP-HOP DEBOUT Avec Thomas RAMIRES LIEU : Campus Jussieu - Centre sportif Jean Talbot : salle d'escrime PRESENTATION DÃ©couvrir et approfondir les bases des diffÃ©rents styles de Danse Hip-Hop debout : Lock Pop House dance New-style Krump Construire et affiner son propre style de danseur Etre capable d'endosser 3 rÃ´les
Total hip arthroplasty is a well-established treatment for arthritis of the hip. The choice of bearing couple used for articulation should be tailored to the patient. This article reviews the history of different bearing surfaces, and outlines the advantages and disadvantages that may influence their use. PMID:20852486
Tailor, Hiteshkumar; Patel, Shelain; Patel, Rahul V; Haddad, Fares S
Background and purpose Two contradictory cementing techniques (using an undersized stem versus a canal-filling stem) can both lead to excellent survival rates, a phenomenon known as the “French paradox”. Furthermore, previous studies have indicated that the type of bone supporting the cement mantle may affect implant survival. To further evaluate the mechanical consequences of variations in cementing technique, we studied the effect of implant size and type of bone supporting the cement mantle on the mechanical performance of cemented total hip arthroplasty, using finite element analysis. Methods In a generic 2-dimensional plane-strain finite element model of a transverse section of a cemented total hip arthroplasty with a Charnley-Kerboull stem, we varied implant size and type of bone supporting the cement mantle. The models were subjected to 2 × 106 cycles of an alternating loading pattern of torque and a transverse load. During this loading history, we simulated cement fatigue crack formation and tracked rotational stability of the implant. Results Canal-filling stems produced fewer cement cracks and less rotation than undersized stems. Cement mantles surrounded by trabecular bone produced more cement cracks and implant rotation than cement mantles surrounded by cortical bone. Interpretation Our investigation provides a possible explanation for the good clinical results obtained with canal-filling Charnley-Kerboull implants. Our findings also indicate that inferior mechanical properties are obtained with these implants if the cement is supported by trabecular bone, which may be minimized by an optimal cementing technique. PMID:19421913
van Aken, Jantien; Scheerlinck, Thierry; Verdonschot, Nico
Background Sufficient primary stability is a prerequisite for the clinical success of cementless implants. Therefore, it is important to have an estimation of the primary stability that can be achieved with new stem designs in a pre-clinical trial. Fast assessment of the primary stability is also useful in the preoperative planning of total hip replacements, and to an even larger extent in intraoperatively custom-made prosthesis systems, which result in a wide variety of stem geometries. Methods An analytical model is proposed to numerically predict the relative primary stability of cementless hip stems. This analytical approach is based upon the principle of virtual work and a straightforward mechanical model. For five custom-made implant designs, the resistance against axial rotation was assessed through the analytical model as well as through finite element modelling (FEM). Results The analytical approach can be considered as a first attempt to theoretically evaluate the primary stability of hip stems without using FEM, which makes it fast and inexpensive compared to other methods. A reasonable agreement was found in the stability ranking of the stems obtained with both methods. However, due to the simplifying assumptions underlying the analytical model it predicts very rigid stability behaviour: estimated stem rotation was two to three orders of magnitude smaller, compared with the FEM results. Conclusion Based on the results of this study, the analytical model might be useful as a comparative tool for the assessment of the primary stability of cementless hip stems. PMID:18817544
Zeman, Maria E; Sauwen, Nicolas; Labey, Luc; Mulier, Michiel; Van der Perre, Georges; Jaecques, Siegfried VN
It is standard practice in many institutions to routinely perform preoperative and postoperative haemoglobin level testing in association with hip joint arthroplasty procedures. It is our observation, however, that blood transfusion after uncomplicated primary hip arthroplasty in healthy patients is uncommon and that the decision to proceed with blood transfusion is typically made on clinical grounds. We therefore question the necessity and clinical value of routine perioperative blood testing about the time of hip resurfacing arthroplasty. We present analysis of perioperative blood tests and transfusion rates in 107 patients undertaking unilateral hybrid hip resurfacing arthroplasty by the senior author at a single institution over a three-year period. We conclude that routine perioperative testing of haemoglobin levels for hip resurfacing arthroplasty procedures does not assist in clinical management. We recommend that postoperative blood testing only be considered should the patient demonstrate clinical signs of symptomatic anaemia or if particular clinical circumstances necessitate. PMID:25349744
Numerical studies were performed to investigate bone cement polymerization, temperature history and thermal osteonecrosis in cemented hip replacements with finite element methods. In this paper, the effects of pre-cooling and pre-heating of the prosthesis and\\/or the cement prior to implantation were simulated. It was found that the cement polymerization initiated near the bone–cement interface and progressed toward the prosthesis when
Chaodi Li; Steven Schmid; James Mason
Background Hip resurfacing arthroplasty (HRA) is considered a bone-preserving procedure and may eliminate proximal femoral stress shielding\\u000a and osteolysis. However, in addition to implant-related stress-shielding factors, various patient-related factors may also\\u000a have an effect on bone mineral density (BMD) of the proximal femur in patients with HRA. Thus, we studied the effects of stem-neck\\u000a angle, demographic variables, and physical functioning on
Arja Häkkinen; Håkan Borg; Mikko Hakulinen; Jukka Jurvelin; Esa Anttila; Tapani Parviainen; Ilkka Kiviranta
BACKGROUND: As longevity of cementless femoral components enters the third decade, concerns arise with long-term effects of fixation mode on femoral bone morphology. We examined the long-term consequences on femoral remodeling following total hip arthroplasty with a porous plasma-sprayed tapered titanium stem. METHODS: Clinical data and radiographs were reviewed from a single center for 97 randomly selected cases implanted with
Brad Ellison; Nicholas A Cheney; Keith R Berend; Adolph V Lombardi Jr; Thomas H Mallory
Squeaking of hip replacements with ceramic-on-ceramic bearings has put the use of this material into question despite its superior wear behavior. Squeaking has been related to implant design. The purpose of this study was to determine the influence of particular acetabular cup and femoral stem designs on the incidence of squeaking and its characteristics.The dynamic behavior of the stem, head
Arne Hothan; Gerd Huber; Cornelius Weiss; Norbert Hoffmann; Michael Morlock
We prepared several pyridine- and pyrimidine-based self-immolative spacer groups to evaluate the significance of the resonance energy of the spacer aromatic ring on the kinetics of 1,4- and 1,6-elimination reactions, which govern spacer disassembly. Subsequently, we relied on a photoactivation procedure to accurately analyze the disassembly kinetics. Beyond providing new results that are relevant for deriving quantitative structure-property relationships, herein, we demonstrate that pH value can be used as an efficient parameter to finely control the disassembly time of a self-immolative spacer after an initial activation. PMID:24652669
Alouane, Ahmed; Labruère, Raphaël; Silvestre, Katherine J; Le Saux, Thomas; Schmidt, Frédéric; Jullien, Ludovic
Introduction of spacers in coating steroid antigen or enzyme conjugates or immunogen is known to exert an influence on the sensitivity of steroid enzyme immunoassays. We have introduced hydrophobic and hydrophilic spacers between enzyme and steroid moieties and studied their effects on functional parameters of enzyme immunoassays, using cortisol as a model steroid. Cortisol-3-O-carboxymethyloxime-bovine serum albumin (F-3-O-CMO-BSA) was used as immunogen to raise the antiserum in New Zealand white rabbits. Three enzyme conjugates were prepared using cortisol-21-hemisuccinate (F-21-HS) as carboxylic derivative of cortisol and horseradish peroxidase (HRP) as an enzyme label. These were F-21-HS-HRP (without spacer), F-21-HS-adipic acid dihydrazide-HRP (adipic acid dihydrazide as hydrophobic spacer), and F-21-HS-urea-HRP (urea as hydrophilic spacer). The influence of hydrophobic and hydrophilic spacers on the functional parameters of assays such as lower detection limit, ED50, and specificity was studied with reference to enzyme conjugate without spacer. The results of the present investigation revealed that the presence of a hydrophilic spacer in the enzyme conjugate decreases the lower detection limit, decreases the ED50, and marginally improves the specificity of assays. These improvements in functional parameters of assays may be due to the decreased magnitude of the overall hydrophobic interactions existing between the spacer in enzyme conjugate and the antigen binding site of the antibody. PMID:18023401
Nara, Seema; Tripathi, Vinay; Chaube, Shail K; Rangari, Kiran; Singh, Harpal; Kariya, Kiran P; Shrivastav, Tulsidas G
Due to the renewed interest in hard-on-hard hip replacement, especially metal-on-metal (MoM) or metal-on-ceramic (MoC) joints, issues relating to their long-term durability need to be addressed. Their effects on the operating environment (human body) and how the body fluid affects the implant materials are the primary concern. For widely used metallic implant materials, such as cobalt–chromium–molybdenum (CoCrMo) alloys, released ions
Yu Yan; Anne Neville; Duncan Dowson
The prognosis associated with the DePuy ASR hip cup is poor and varies according to the series. This implant was withdrawn from use in 2010 and all patients needed to be assessed. We present the results of the assessment of our patients treated with this device, according to the Spanish Society of Hip Surgery (SECCA) algorithm published in 2011. This retrospective study evaluates 83 consecutive ASR cups, followed up at a mean of 2.9 years. Serum levels of chromium and cobalt, as well as the acetabular abduction angle, were determined in order to assess their possible correlation with failure, defined as the need for revision surgery. The mean Harris Hip Score was 83.2 (range 42–97). Eight arthroplasties (13.3%) required revision due to persistent pain and/or elevated serum levels of chromium/cobalt. All the cups had a correct abduction angle, and there was no correlation between elevated serum levels of metal ions and implant failure. Since two previous ASR implants were exchanged previously to the recall, the revision rate for ASR cups in our centre is 18.2% at 2.9 years.
Fernández-Valencia, Jenaro; Gallart, Xavier; Bori, Guillem; Ramiro, Sebastián Garcia; Combalía, Andrés; Riba, Josep
Background Metal-on-metal hip resurfacing is an alternative to metal-on-metal total hip arthroplasty, especially for young and physically active patients. However, wear which might be detected by increased serum ion levels is a matter of concern. Methods The aims of this preliminary study were to determine the raise of metal ion levels at 2-years follow-up in a prospective setting and to evaluate differences between patients with either resurfacing or total hip arthroplasty. Furthermore we investigated if the inclination of the acetabular component and the arc of cover would influence these findings. Therefore, 36 patients were followed prospectively. Results The results showed increments for Co and Cr in both implant groups. Patients treated with large-diameter total hip arthroplasty showed fourfold and threefold, respectively, higher levels for Co and Cr compared to the resurfacing group (Co: p?0,001 and Cr: p?=?0,005). Nevertheless, we observed no significant correlation between serum ion levels, inclination and arc of cover. Discussion In order to clarify the biologic effects of ion dissemination and to identify risks concerning long-term toxicity of metals, the exposure should be monitored carefully. Therefore, long-term studies have to be done to determine adverse effects of Co and Cr following metal-on-metal hip replacement. PMID:22494794
Degenerative problems of the hip in patients with childhood and adult onset neuromuscular disorders can be challenging to treat. Many orthopaedic surgeons are reluctant to recommend total hip replacement (THR) for patients with underlying neuromuscular disorders due to the perceived increased risks of dislocation, implant loosening, and lack of information about the functional outcomes and potential benefits of these procedures in these patients. Modular femoral components and alternative bearings which facilitate the use of large femoral heads, constrained acetabular components and perhaps more importantly, a better understanding about the complications and outcomes of THR in the patient with neuromuscular disorders, make this option viable. This paper will review the current literature and our experience with THR in the more frequently encountered neuromuscular disorders. Cite this article: Bone Joint J 2014;96-B(11 Suppl A):27-31. PMID:25381404
Kraay, M J; Bigach, S D
Alumina-on-alumina bearings in total hip arthroplasty have been developed in an attempt to minimise debris and the occurrence of osteolytic lesions. The outstanding tribological properties of this bearing system are explained by low surface roughness, high hardness for major scratch resistance, and high wettability. Since the 1970s, technological improvements in the manufacturing process of alumina components together with a better understanding of Morse taper technology have provided a surgical grade material with high density, high purity and small grains. Published studies on the outcome of total hip arthroplasty performed with this new generation of implants showed high survivorship especially in young and active patients, with survival rates free of revision of 90.8% to 97.4% at ten years. However, concern remains over ceramic liner fracture and squeaking, which has been noted recently with increasing prevalence. This review will discuss the current knowledge on the use of alumina-on-alumina bearings. PMID:21191579
Zaoui, Amine; Zadegan, Frederic; Sedel, Laurent; Nizard, Remy
Alumina-on-alumina bearings in total hip arthroplasty have been developed in an attempt to minimise debris and the occurrence of osteolytic lesions. The outstanding tribological properties of this bearing system are explained by low surface roughness, high hardness for major scratch resistance, and high wettability. Since the 1970s, technological improvements in the manufacturing process of alumina components together with a better understanding of Morse taper technology have provided a surgical grade material with high density, high purity and small grains. Published studies on the outcome of total hip arthroplasty performed with this new generation of implants showed high survivorship especially in young and active patients, with survival rates free of revision of 90.8% to 97.4% at ten years. However, concern remains over ceramic liner fracture and squeaking, which has been noted recently with increasing prevalence. This review will discuss the current knowledge on the use of alumina-on-alumina bearings. PMID:21191579
Hannouche, Didier; Zaoui, Amine; Zadegan, Frédéric; Sedel, Laurent; Nizard, Rémy
In this work, we report on two new asymmetric dicopper cryptates, characterized by alternate furanyl and p-xylyl spacers. The results of the potentiometric, UV-vis and X-ray diffraction studies are discussed. In particular, for one of the cages in the octaprotonated form, the crystal structure of the complex with nitrate is described. From the point of view of the anion binding in water, the new dicopper cryptates display stronger similarities to each other than to the symmetric analogues (i.e. p-xylyl and furan cryptates). The substitution of even only one spacer modifies the distance between the metal ions. This prevents the development of the CT band, typically accompanying the binding of halides by the furan cryptate, and favors the formation of complexes of different stoichiometry with the linear azide anion, not observed for the symmetric cryptates. The obtained results may be very helpful in the design of new molecular receptors based on dimetallic cryptates, in particular for the tuning of the sensitivity towards specific anionic substrates. PMID:24926852
Bergamaschi, Greta; Boiocchi, Massimo; Perrone, Maria Lucia; Poggi, Antonio; Viviani, Ivan; Amendola, Valeria
Background Various qualitative and quantitative radiological geometrical parameters can be of great help when assessing dysplasia of the hip joint and in understanding developmental processes of the infant hip. There are few data on the normal values of the hip joint at different ages. Objective To perform radiographic measurements on hip joints considered to be anatomically normal and to provide
Péter Than; Tamás Sillinger; János Kránicz; Árpád Bellyei
The differential diagnosis of hip pain is broad and includes intra-articular pathology, extra-articular pathology, and mimickers, including the joints of the pelvic ring. With the current advancements in hip arthroscopy, more patients are being evaluated for hip pain. In recent years, our understanding of the functional anatomy around the hip has improved. In addition, because of advancements in magnetic resonance
Lisa M. Tibor; Jon K. Sekiya
The endeavor towards life-like restoration has helped nurture new vistas in the art and science of implant dentistry. The protocol of "restoration-driven implant placement" ensures that the implant is an apical extension of the ideal future restoration and not the opposite. Meticulous pre-implant evaluation of soft and hard tissues, diagnostic cast and use of aesthetic wax-up and radiographic template combined with surgical template can simplify the intricate roadmap for appropriate implant treatment.By applying the harmony of artistic skill, scientific knowledge and clinical expertise, we can simply master the outstanding implant success in requisites of aesthetics, phonetics and function. PMID:20376237
Luthra, Kaushal K
Developmental dysplasia of the hip (DDH) or congenital hip dysplasia (CDH) is the most prevalent developmental childhood hip disorder. It includes a wide spectrum of hip abnormalities ranging from dysplasia to subluxation and complete dislocation of the hip joint. The natural history of neglected DDH in adults is highly variable. The mean age of onset of symptoms is 34.5 years for dysplastic DDH, 32.5 years for low dislocation, 31.2 years for high dislocation with a false acetabulum, and 46.4 years for high dislocation without a false acetabulum. Thorough understanding of the bony and soft tissue deformities induced by dysplasia is crucial for the success of total hip arthroplasty. It is important to evaluate the existing acetabular deformity three-dimensionally, and customize the correction in accordance with the quantity and location of ace tabular deficiencies. Acetabular reconstruction in patients with DDH is challenging. Interpretation of published data is difficult and should be done with caution because most series include patients with different types of hip disease. In general, the complication rate associated with THA is higher in patients with hip dysplasia than it is in patients with osteoarthritis. Overall, clinical and functional outcomes following THA in patients hip dysplasia (DDH) differ from those treated for primary hip osteoarthritis, possibly due to the lower age and level of activity. Although function scores decline with age, the scores for pain and range of motion presented with a statistically significant improvement in the long-term. PMID:25386570
Sakellariou, Vasileios I.; Christodoulou, Michael; Sasalos, Gregory; Babis, George C.
A multicenter retrieval analysis of 231 modular hip implants was done to investigate the effects of material combination, metallurgic condition, flexural rigidity, head and neck moment arm, neck length, and implantation time on corrosion and fretting of modular taper surfaces. Scores for corrosion and fretting were assigned to medial, lateral, anterior, and posterior quadrants of the necks, and proximal and distal regions of the heads. Neck and head corrosion and fretting scores were found to be significantly higher for mixed alloy versus similar alloy couples. Moderate to severe corrosion was observed in 28% of the heads of similar alloy couples and 42% of the heads of mixed alloy couples. Differences in corrosion scores were observed between components made from the same base alloy, but of different metallurgic conditions. Corrosion and fretting scores tended to be higher for heads than necks. Implantation time and flexural rigidity of the neck were predictors of head and neck corrosion and head fretting. The results of this study suggest that in vivo corrosion of modular hip taper interfaces is attributable to a mechanically-assisted crevice corrosion process. Larger diameter necks will increase neck stiffness and may reduce fretting and subsequent corrosion of the taper interface regardless of the alloy used. Increasing neck diameter must be balanced, however, with the resulting loss of range of motion and joint stability. PMID:12151892
Goldberg, Jay R; Gilbert, Jeremy L; Jacobs, Joshua J; Bauer, Thomas W; Paprosky, Wayne; Leurgans, Sue
This letter to the editor is in response to 3 articles on the use of the Norplant implant contraceptive in The Indian Health Service (IHS) Provider. Norplant and the FDA-approved Depo-Provera now expand contraceptive options for women. All IHS and 638 sites might be able to offer both options. Several of the authors expressed concern regarding decreased Norplant effectiveness in heavier patients. Norplant is still more effective than any other currently available reversible contraceptive in the US at all weights. Many experts feel the current silastic capsule provides adequate hormone levels even in heavier women. The Crow Service Unit has initiated their Norplant program, although the Wyeth consent form seems unnecessarily extensive. The Albuquerque Service Unit consent form simply describes the procedure and confirms that patients have read and understand the fact sheet. The theoretical risk of thromboembolism is vastly outweighed by the potential benefit of reliable contraception in high risk alcoholic women, except perhaps in women with severe liver disease. While Norplant is expensive, programs need to consider the actual cost of a pregnancy, potential complications, and the financial and social costs of unintended pregnancy. For those in difficult straits, the manufacturer has set up a foundation for obtaining Norplant free of charge. Depo-Provera comes in a 150 mg dose vial that is given every 3 months. The mean time to ovulation is 4.5 months from the last dose. The adverse reaction spectrum is similar to Norplant as they are both progesterone-related agents. Providers and clinics should reduce barriers to family planning by giving out more pill packs at a time; letting adolescents who wish to delay their first pelvic exam have 3 months of pills without an exam; making condoms available in exam rooms rather than through pharmacy prescriptions; and increasing patient accessibility to the morning-after pill. PMID:12288838
Pure alumina ceramic has been in clinical use in orthopaedics since 1971 and, currently, up to 5 million components have been implanted. Alumina offers advantages like stability, biocompatibility and low wear; however, it has limited strength. Applications are limited by design considerations. Engineers in biomaterials have worked on improving the performance of the material by optimising the manufacturing process. To fulfil surgeons’ and patients’ increasingly exacting requirements, ceramists have also developed a new ceramic composite, the alumina matrix composite (AMC). This material combines the great principles of the reinforcement of ceramics with its tribological qualities and presents a better mechanical resistance than alumina. The examination of the tribological situation of AMC, especially under the challenging conditions of hydrothermal ageing, shows the aptitude of this material in wear applications. The US Food and Drug Administration (FDA) has approved ceramic ball heads articulating against polyethylene inserts. Since its introduction, more than 65,000 ball heads and 40,000 inserts of AMC have been implanted. With a 6-year follow up, no complication has been reported to the manufacturer. Improved toughness and the excellent wear of AMC makes it a potentially more flexible alternative to the more traditional alumina for hip prostheses. PMID:18043920
The pathogenesis and clinical course of hip dysplasia in cerebral palsy and Down syndrome is different than idiopathic developmental dysplasia of the hip. Unlike idiopathic developmental hip dysplasia, hip development in cerebral palsy and Down syndrome is typically normal in utero and instability develops after birth secondary to musculoskeletal disorders associated with the disease condition. For this reason, treatment protocols in Down syndrome and cerebral palsy hip dysplasia differ greatly from protocols designed to treat idiopathic hip dysplasia. The purpose of this review is to describe the pathologic hip morphology that results from cerebral palsy and Down syndrome. PMID:23764790
Schoenecker, Jonathan G
Implant malalignment in hip arthroplasty increases the risk of revision surgery due to problems such as hip instability, wear, and impingement. Traditional instrumentation lacks accuracy and does not individualize the goal. Computer-assisted surgery (CAS) and patient-specific solutions improve accuracy but add considerably to the cost, amongst other drawbacks. We developed an adjustable mechanical device, called Optihip, which is set to a patient-specific goal preoperatively and is independent of pelvis position intraoperatively. The purpose of the present study was to evaluate Optihip's accuracy ex vivo. Acetabular components were implanted into six cadaveric specimens, 12 hips, by two surgeons, with the device individually adjusted according to preoperative templating on computed tomography (CT) images relative to defined acetabular rim landmarks; options also exist for templating on single or biplanar X-rays. Intraoperatively, the device was positioned on the corresponding anatomical landmarks allowing the insertion of a guide pin, which then defined the desired orientation of the acetabular cup during impaction. Mean absolute difference between the preoperatively planned cup alignment and final acetabular cup orientation, measured from postoperative CT images, was 2.5±1.2° for inclination and 2.5±2.2° for version with maximum values of 4.7° and 6.8°, respectively. Compared with previous in vivo reports, Optihip guided the acetabular cup orientation more accurately than conventional hip arthroplasty, and comparably to CAS or patient-specific systems, while fitting into the normal surgical workflow. Although clinical testing is required to confirm these experimental results, the positive ex vivo accuracy suggests good potential for improving revision rates and patient functional outcome. PMID:25313024
Shandiz, Mohsen Akbari; MacKenzie, James R; Hunt, Stephen; Anglin, Carolyn
The search for the improvement of implant fixation in bone resulted several years ago in the introduction of calcium phosphate coatings on orthopaedic (and dental) implants. Since then many animal experiments, especially on hydroxylapatite coatings, have been performed. By now the first promising results from clinical studies are also available. In this review, the plasma-spray process is described and some of the current techniques for the analysis of retrieved implants are discussed. It is now widely understood that the calcium phosphate hydroxylapatite is osteoconductive. Various experimental animal studies revealed the capability of calcium phosphate coatings to enhance implant fixation, especially under specific or less optimal conditions such as a with a porous implant, loose fit, micromotion or experimental arthritis. Clinical studies, including the analysis of retrieved hydroxylapatite coated hip implants, confirmed these promising results and as a consequence, hydroxylapatite coated total joint prostheses are now used on a large scale. Two questions that are closely related with each other are very actual, e.g. the strength of the coating-substrate interface and how stable or crystalline should hydroxylapatite coatings be for a proper clinical function? There does not yet seem to be a consistent answer to these questions. PMID:7877559
Dhert, W J
Systemic lupus erythematosus is a multisystem disease with a large spectrum of clinical manifestations and a variable course. Lupus is marked by both humoral and cellular immunologic abnormalities, including multiple auto-antibodies especially anti DNA antibodies. Epidemiology - female predominance, occurring usually between second and fourth decade of life, more frequently in hispanic and black patients. Family predominance has been noticed. Provocative agents - ultraviolet light, viral infections, drugs and situational stresses. Pathogenesis - pathological features can affect a large spectrum of internal organs and systems - osteoarticulary injuries, skin rash, lymphadenopathy, glomerulonephritis, myocarditis, digestive system lesions. Musculo skeletal abnormalities include migratory arthritis, effusion and stiffness in small and large joints. Articular erosions are uncommon. Skeletal abnormalities include osteopenia and osteonecrosis, due to two pathological mechanisms: vasculitis and long term corticotherapy. Fifteen to twenty percent of SLE patients are affected by femoral head avascular necrosis (FHAN). Diagnosis rests on clinical signs - hip pain, limited range of motion, walking with a limp.; radiological findings - best grouped in Arlet-Ficat standing system; MRI - high sensitivity, especially in infraradiological stages. Treatment - in incipient stages core decompression represents the best therapeutical option. In advanced, arthritis stages, total hip arthroplasty (THA) is the standart treatment. Three implant types are available: bipolar, uncemented and cemented. An increased number of cotyloidites occurred after bipolar implants. Emphasised osteopenia and excessive bleeding represent contraindications for uncemented implants. Considering all of this, cemented implants are considered, the right choice, methacrylate cement providing strong and durable fixation of THA implants to bone. No meaningful differences were observed in postoperative functional recovery between LSE patients and other etiology FHAN patients. PMID:17966453
Orban, H; Cîrstoiu, C; Adam, R
The medial approach to the hip via the adductors, as described by Ludloff or Ferguson, provides restricted visualization and incurs a risk of neurovascular lesion. We describe a minimally invasive medial hip approach providing broader exposure of extra- and intra-articular elements in a space free of neurovascular structures. With the lower limb in a "frog-leg" position, the skin incision follows the adductor longus for 6cm and then the aponeurosis is incised. A slide plane between all the adductors and the aponeurosis is easily released by blunt dissection, with no interposed neurovascular elements. This gives access to the lesser trochanter, psoas tendon and inferior sides of the femoral neck and head, anterior wall of the acetabulum and labrum. We report a series of 56 cases, with no major complications: this approach allows treatment of iliopsoas muscle lesions and resection or filling of benign tumors of the cervical region and enables intra-articular surgery (arthrolysis, resection of osteophytes or foreign bodies, labral suture). PMID:25164350
Chiron, P; Murgier, J; Cavaignac, E; Pailhé, R; Reina, N
Lipoma arborescens is a rare intra-articular lesion characterized by extensive villous proliferation of the synovial membrane and hyperplasia of subsynovial fat. Although it has been described as arising from traumatic, inflammatory, rheumatologic, developmental, and neoplastic causes, its etiology remains unknown. This article describes in detail--for the first time in the orthopedic literature-a case of lipoma arborescens of the hip. Clinical presentation, histologic and radiographic findings, and treatment of this rare lesion are discussed. Based on clinical, radiologic, and surgical evaluation, differential diagnosis for this lesion should include other conditions that cause synovial thickening, proliferation, and joint effusion--for example, synovial chondromatosis, pigmented villonodular synovitis, synovial hemangiomatosis, and rheumatoid arthritis. Description of this case covers the full radiologic evaluation, including magnetic resonance imaging (MRI), diagnostic pathologic description, and minimum 24-month follow-up. Although lipoma arborescens of the hip is a rare condition, it should be considered in the differential diagnosis of patients with its characteristic clinical prodrome and MRI findings confirming a periarticular fatty mass. PMID:12041520
Wolf, Robert S; Zoys, George N; Saldivar, Victor A; Williams, Ronald P
Patient: Male, 43 Final Diagnosis: Neurofibromatosis Symptoms: Hip pain Medication: — Clinical Procedure: — Specialty: Orthopedics and Traumatology Objective: Rare disease Background: Neurofibromatosis type 1 is a disease known for orthopedic manifestations such as spine deformities, congenital pseudarthrosis of the tibia and other bony dysplasias; joint dislocations are rare. Joint arthritis caused by neurofibromatosis, with a stable hip, has never been reported in the English literature before. Case Report: A 43-year-old man diagnosed with neurofibromatosis type 1 (NF-1) presented with hip pain of 5 years duration, with no history of trauma and no clinical or radiological signs of dislocation. He had classical clinical and radiological signs of hip arthritis, with acetabular erosions and femoral head arthritis. The patient was treated with total hip arthroplasty metal-on-metal (MoM). Conclusions: Hip arthritis alone without subluxation or dislocation due to NF-1 is an extremely rare presentation. This is the first reported presentation and provisional treatment with total hip arthroplasty. PMID:24587854
Alrumaih, Husam; Ilyas, Imran; Kashif, Syed
Objective Using biomechanical studies, this research aims to compare hip capsulorrhaphy in rabbits, carried out with two different techniques: capsulorrhaphy with simple sutures and with anchors. Method Thirteen New Zealand Albino (Oryctolaguscuniculus) male rabbits, twenty-six hip joints, were used. First, a pilot project was performed with three rabbits (six hip joints). This experiment consisted of ten rabbits divided into two groups: group 1 underwent capsulorrhaphy on both right and left hips with simple suture using polyglycolic acid absorbable thread, and group 2 underwent capsulorrhaphy with titanium anchors. After a four-week postoperative period, the animals were euthanized and the hip joints were frozen. On the same day of the biomechanical studies, after the hip joints were previously unfrozen, the following parameters were evaluated: rigidity, maximum force, maximum deformity and energy. Results There was no relevant statistical difference in rigidity, maximum force, maximum deformity and energy between the simple suture and anchor groups. Conclusion Through biomechanical analyses, using parameters of rigidity, maximum force, maximum deformity and energy, it has been shown that capsulorrhaphy with simple suture and with anchors has similar results in rabbit hip joints. Level of Evidence II, Prospective Comparative Study. PMID:24453618
Garcia Filho, Fernando Cal; Guarniero, Roberto; de Godoy Junior, Rui Maciel; Pereira, Cesar Augusto Martins; Matos, Marcos Almeida; Garcia, Lucas Cortizo
The purpose of the current study was to assess the validity, internal consistency, and reproducibility of a short, self-administered hip score designed for use in younger patients with higher demands and expectations than older patients with degenerative joint disease. Validity and internal consistency was studied with 48 consecutive patients with a mean age of 33 years with intractable hip pain and normal plain radiographs. Reproducibility was assessed from data on an additional random sample of 17 patients with hip pain. The Pearson correlation coefficients were 0.82 and 0.59 between the nonarthritic hip score and the Harris hip score and Short Form-12, respectively showing validity. Cronbach's coefficient alpha measuring the internal consistency within each of the score's four domains ranged from 0.69 to 0.92. The test and retest reproducibility ranged from 0.87 to 0.95 for the four subsets and was 0.96 overall. This short, self-administered questionnaire regarding hip pain in young patients with increased activity demands and high treatment expectations is valid compared with previous measures of hip performance, is internally consistent, and is reproducible. PMID:12579003
Christensen, Christian P; Althausen, Peter L; Mittleman, Murray A; Lee, Jo-ann; McCarthy, Joseph C
This article discusses the criteria used for implant success and failure, the classification of implant failures, the causative factors, and diagnosis of the failing and failed implant. In spite of the impressive success rates of osseointegrated dental implants, failures occur and in some studies the incidence of failure is high. Many studies do not use objective criteria to define success and confuse survival with success. The criteria used affect reported success rates. Implant failures may occur early (primary) after implant placement or after the implant is loaded (secondary). There is no single aetiological factor and failures have been attributed to poor surgical technique, host factors that impair healing, poor bone quality, peri-implant infections, poor prosthesis design and traumatic loading conditions. Early diagnosis of problems is critical and every effort should be made to treat the problem while the damage can still be managed or even reversed. PMID:10686922
O'Mahony, A; Spencer, P
Breast implants have evolved from the original saline-filled, smooth-surfaced silicone rubber bag to silicone gel-filled smooth-walled sacs to a combination of a silicone gel-filled bag within a saline-filled sac, and, most recently, a reversed, double-lumen implant with a saline bag inside of a gel-filled bag. Texture-surfaced implants were first used in 1970 when the standard silicone gelfilled implant was covered
Robert A. Ersek; Jose Alberto Navarro; Dora Zsofia Nemeth; George Sas
The objectives of this study were to describe the essential magnetic resonance imaging (MRI) features of bone marrow edema\\u000a syndromes affecting the hip joint. In addition, to evaluate the role of MRI in the assessment of hip joint involvement in\\u000a different clinical settings that may share similar clinical findings. Thirty-four patients who complained of hip pain were\\u000a studied consecutively. Of
Yasser Ragab; Yasser Emad; Alaa Abou-Zeid
The teflon hip arthroplasty design was used by Sir John Charnley in the early 60's but was taken off the market due to high complication rates. A case is reported of an intrapelvic granuloma after total hip arthroplasty following the use of a teflon socket. This appears to be the last surviving patient treated by Sir John Charnley using a Teflon hip socket design. PMID:20306978
Gheorghiu, Daniel; Peter, Viju; Lynch, Martin
We performed a prospective study in 108 consecutive patients (116 hips) who were followed for a minimum of 10 years (10–12 years) after primary total hip arthroplasty using an uncemented porous-coated anatomic (PCA) hip prosthesis. The average age of the patients at operation was 48.4 years (range, 19–85 years), and the diagnosis was avascular necrosis of the femoral head in
Young-Hoo Kim; Jun-Shik Kim; Soon-Ho Cho
\\u000a Aseptic loosening is seen as the most important cause if late failure after total hip replacement surgery and it is believed\\u000a that hip joint forces on the hip prosthesis from movements such as stair climbing, and even walking, over a long time can\\u000a lead to the loosening of the prosthesis. Motion analysis was carried out using 6 inferred cameras and
D. S. O’Reilly; M. F. Donoghue; T. M. McGloughlin; M. T. Walsh
Standard magnetic resonance imaging (MRI) as well as MR arthrography (MRA) have been important diagnostic tools to assess for a spectrum of clinical presentations related to the hip. MRA has allowed the radiologist to closely examine intracapsular structures such as the acetabular labrum. In this article, we provide a general review of soft tissue and osseous anatomy of hips, especially focusing on the MR appearances of the acetabular labrum and the osseous morphology of the greater trochanter and ischial tuberosity with their muscle and tendon attachments. In addition, current topics in recent literature will be discussed such as femoroacetabular impingement (FAI) and rotator cuff tears of the hip. PMID:18183574
Hong, Raymond J; Hughes, Tudor H; Gentili, Amilcare; Chung, Christine B
Dimeric (gemini) surfactants are made up of two amphiphilic moieties connected at the level of, or very close to, the head groups by a spacer group of varying nature: hydrophilic or hydrophobic, rigid or flexible. These surfactants represent a new class of surfactants that is finding its way into surfactant-based formulations. The nature of the spacer group (length, flexibility, chemical
A detailed quantitative analysis of the hot carrier degradation in the spacer region of LDD nMOSFETs using stress conditions for maximum hole (Vg ~ Vt), substrate (Isubmax) and electron (Vg = Vd) current from microseconds is presented. Damage in the spacer region reveals a two-stage drain series resistance degradation with an early stage lasting about 100 ms. The nature of
S. K. Manhas; M. Merlyne De Souza; Anthony S. Oates
Three-dimensional microstructuring of carbon by thermoplastic spacer evaporation during pyrolysis by using a novel low-cost process that involved thermoplastic spacer (paraffin wax) evap- oration during mask application, UV exposure, development and pyrolysis. In case of three-dimen- sional
Chung, Deborah D.L.
The results are described about the preliminary analysis of the effect of the grid spacers on the heat transfer during reflood phase of a PWR LOCA. Experiments at JAERI and other facilities showed substantial heat transfer enhancement near the grid spacer...
J. Sugimoto, Y. Murao
LBNL-6122E Window Spacers and Edge Seals in Insulating Glass Units: A State-of-the-Art Review of California. #12;! #12;1 Window Spacers and Edge Seals in Insulating Glass Units: A State-of-the-Art Review), Windows & Envelope Materials Group, Berkeley, CA 94720- 8134, USA Abstract Insulating glass (IG) units
We investigated the influence of dielectric spacer thickness on the metamaterials absorber at microwave frequency. The absorption feature was demonstrated and characterized by the numerical simulations and experiments. The thickness of FR4 spacer was varied to examine the electromagnetic response of the short and long wires structure. It was found that there existed two different absorption mechanisms which were concerned
Tao Wang; Lu Wang; Yan Nie; Rongzhou Gong
The Effect of Charge-Reversal Amphiphile Spacer Composition on DNA and siRNA Delivery Xiao April 7, 2010 A series of charge-reversal amphiphiles with different spacers separating the headgroup from the hydrophobic chains are described for delivery of DNA and siRNA. Among them, the amphiphiles
CPI's human-implantable automatic implantable defibrillator (AID) is a heart assist system, derived from NASA's space circuitry technology, that can prevent erratic heart action known as arrhythmias. Implanted AID, consisting of microcomputer power source and two electrodes for sensing heart activity, recognizes onset of ventricular fibrillation (VF) and delivers corrective electrical countershock to restore rhythmic heartbeat.
Object Anterior cervical plating decreases the risk of pseudarthrosis following anterior cervical discectomy and fusion (ACDF). Dysphagia is a common complication of ACDF, with the anterior plate implicated as a potential contributor. A zero-profile, stand-alone polyetheretherketone (PEEK) interbody spacer has been postulated to minimize soft-tissue irritation and postoperative dysphagia, but studies are limited. The object of the present study was to determine the clinical and radiological outcomes for patients who underwent ACDF using a zero-profile integrated plate and spacer device, with a focus on the course of postoperative prevertebral soft-tissue thickness and the incidence of dysphagia. Methods Using a surgical database, the authors conducted a retrospective analysis of all patients who had undergone ACDF between August 2008 and October 2011. All patients received a Zero-P implant (DePuy Synthes Spine). The Neck Disability Index (NDI) and visual analog scale (VAS) scores for arm and neck pain were documented. Dysphagia was determined using the Bazaz criteria. Prevertebral soft-tissue thickness, spinal alignment, and subsidence were assessed as well. Results Twenty-two male and 19 female consecutive patients, with a mean age of 58.4 ± 14.68, underwent ACDF (66 total operated levels) in the defined study period. The mean clinical follow-up in 36 patients was 18.6 ± 9.93 months. Radiological outcome in 37 patients was assessed at a mean follow-up of 9.76 months (range 7.2-19.7 months). There were significant improvements in neck and arm VAS scores and the NDI following surgery. The neck VAS score improved from a median of 6 (range 0-10) to 0 (range 0-8; p < 0.001). The arm VAS score improved from a median of 2 (range 0-10) to 0 (range 0-7; p = 0.006). Immediate postoperative dysphagia was experienced by 58.4% of all patients. Complete resolution was demonstrated in 87.8% of affected patients at the latest follow-up. The overall median Bazaz score decreased from 1 (range 0-3) immediately postoperatively to 0 (range 0-2; p < 0.001) at the latest follow-up. Prevertebral soft-tissue thickness significantly decreased across all levels from a mean of 15.8 ± 4.38 mm to 10.1 ± 2.93 mm. Postoperative lordosis was maintained at the latest follow-up. Mean subsidence from the immediate postoperative to the latest follow-up was 4.1 ± 4.7 mm (p < 0.001). Radiographic fusion was achieved in 92.6% of implants. No correlation was found between prevertebral soft-tissue thickness and Bazaz dysphagia score. Conclusions A zero-profile integrated plate and spacer device for ACDF surgery produces clinical and radiological outcomes that are comparable to those for nonintegrated plate and spacer constructs. Chronic dysphagia rates are comparable to or better than those for previously published case series. PMID:25105338
Njoku, Innocent; Alimi, Marjan; Leng, Lewis Z; Shin, Benjamin J; James, Andrew R; Bhangoo, Sandeep; Tsiouris, Apostolos John; Härtl, Roger
Objective Cervical laminoplasty has been widely accepted as one of the major treatments for cervical myelopathy and various modifications and supplementary procedures have been devised to achieve both proper decompression and stability of the cervical spine. We present the retrospectively analyzed results of a modified unilateral open-door laminoplasty using hydroxyapatite (HA) spacers and malleable titanium miniplates. Methods From June 2008 to May 2012, among patients diagnosed with cervical spondylotic myelopathy and ossification of posterior longitudinal ligament, the patients who received laminoplasty were reviewed. Clinical outcome was assessed using Frankel grade and Japanese Orthopaedic Association score. The radiologic parameters were obtained from plain films, 3-dimensional computed tomography and magnetic resonance images. Results A total of 125 cervical laminae were operated in 38 patients. 11 patients received 4-level laminoplasty and 27 patients received 3-level laminoplasty. Postoperatively, the mean Frankel grade and JOA score were significantly improved from 3.97 to 4.55 and from 12.76 to 14.63, respectively (p<0.001). Radiologically, cervical curvature was worsened from 19.09 to 15.60 (p=0.025). The percentage of range of motion preservation was 73.32±22.39%. The axial dimension of the operated spinal canal was increased from 1.75 to 2.70 cm2 (p<0.001). Conclusion In the presenting study, unilateral open-door laminoplasty using HA spacers and miniplates appears to be a safe, rapid and easy procedure to obtain an immediate and rigid stabilization of the posterior elements of the cervical spine. This modified laminoplasty method showed effective expansion of the spinal canal and favorable clinical outcomes. PMID:25346767
Jin, Sung-Won; Kim, Bum-Joon; Choi, Jong-Il; Ha, Sung-Kon; Kim, Sang-Dae; Lim, Dong-Jun
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. PMID:22900164
Kaulhausen, Thomas; Zarghooni, Kourosh; Stein, Gregor; Knifka, Jutta; Eysel, Peer; Koebke, Juergen; Sobottke, Rolf
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. PMID:22900164
Kaulhausen, Thomas; Zarghooni, Kourosh; Stein, Gregor; Knifka, Jutta; Eysel, Peer; Koebke, Juergen; Sobottke, Rolf
Background All prostheses with metallic components release metal debris that can potentially activate the immune system. However, implant-related metal hyper-reactivity has not been well characterized. In this study, we hypothesized that adaptive immunity reaction(s), particularly T-helper type 1 (Th1) responses, will be dominant in any metal-reactivity responses of patients with total joint replacements (TJAs). We tested this hypothesis by evaluating lymphocyte reactivity to metal "ions" in subjects with and without total hip replacements, using proliferation assays and cytokine analysis. Methods Lymphocytes from young healthy individuals without an implant or a history of metal allergy (Group 1: n = 8) were used to assess lymphocyte responses to metal challenge agents. In addition, individuals (Group 2: n = 15) with well functioning total hip arthroplasties (average Harris Hip Score = 91, average time in-situ 158 months) were studied. Age matched controls with no implants were also used for comparison (Group 3, n = 8, 4 male, 4 female average age 70, range 49–80). Group 1 subjects' lymphocyte proliferation response to Aluminum+3, Cobalt+2, Chromium+3, Copper+2, Iron+3, Molybdenum+5, Manganeese+2, Nickel+2, Vanadium+3 and Sodium+2 chloride solutions at a variety of concentrations (0.0, 0.05, 0.1, 0.5, 1.0 and 10.0 mM) was studied to establish toxicity thresholds. Mononuclear cells from Group 2 and 3 subjects were challenged with 0.1 mM CrCl3, 0.1 mM NiCl2, 0.1 mM CoCl2 and approx. 0.001 mM titanium and the reactions measured with proliferation assays and cytokine analysis to determine T-cell subtype prominence. Results Primary lymphocytes from patients with well functioning total hip replacements demonstrated a higher incidence and greater magnitude of reactivity to chromium than young healthy controls (p < 0.03). Of the 15 metal ion-challenged subjects with well functioning total hip arthroplasties, 7 demonstrated a proliferative response to Chromium, Nickel, Cobalt and/or Titanium (as defined by a statistically significant >2 fold stimulation index response, p < 0.05) and were designated as metal-reactive. Metals such as Cobalt, Copper, Manganese, and Vanadium were toxic at concentrations as low as 0.5 mM while other metals, such as Aluminum, Chromium, Iron, Molybdenum, and Nickel, became toxic at much higher concentrations (>10 mM). The differential secretion of signature T-cell subsets' cytokines (Th1 and Th2 lymphocytes releasing IFN-gamma and IL-4, respectively) between those total hip arthroplasty subjects which demonstrated metal-reactivity and those that did not, indicated a Th1 type (IFN-gamma) pro-inflammatory response. Conclusion Elevated proliferation and production of IFN-gamma to metals in hip arthroplasty subjects' lymphocytes indicates that a Th1 (vs. Th2) type response is likely associated with any metal induced reactivity. The involvement of an elevated and specific lymphocyte response suggests an adaptive (macrophage recruiting) immunity response to metallic implant debris rather than an innate (nonspecific) immune response. PMID:18271968
Hallab, Nadim James; Caicedo, Marco; Finnegan, Alison; Jacobs, Joshua J
Abstract: We previously reported on the metal ion concentrations of cobalt, chromium, and titanium that were found in the serum of patients three years after they had undergone primary total hip arthroplasty as compared with the concentrations found in the serum of control patients who did not have an implant. This study is a concise update on the serum metal levels found in a cohort of these patients ten years after the time of hip implantation. Of the original seventy-five subjects, metal ion levels were available for forty patients (53%). Ten patients (hybrid group) had received a hybrid total hip replacement that consisted of a modular cobalt-alloy femoral stem with a cobalt-alloy femoral head that had been inserted with cement and a titanium acetabular socket that had been inserted without cement. Nine patients (cobalt-chromium [CoCr] group) had received an implant with an extensively porous-coated modular cobalt-alloy femoral stem and femoral head along with a titanium acetabular socket; the femoral and acetabular components had each been inserted without cement. Eight patients (titanium group) had undergone insertion of a proximally porous-coated modular titanium-alloy femoral stem with a cobalt-alloy femoral head and a titanium acetabular socket; the femoral and acetabular components had each been inserted without cement. Thirteen patients (control group) from the original control group of patients who had not received an implant served as control subjects. Serum metal levels were measured with use of high-resolution sector field inductively coupled plasma mass spectrometry. The hybrid total hip arthroplasty group had mean cobalt levels that were 3.2 times higher at 120 months than they were at baseline, and the cobalt levels in that group were significantly higher than those in the titanium total hip arthroplasty group at thirty-six, sixty, eighty-four, ninety-six, and 120 months (p < 0.01). The hybrid group had mean chromium levels that were 3.9 times higher at 120 months than they were at baseline, and the CoCr total hip arthroplasty group had chromium levels that were 3.6 times higher at 120 months than they were at baseline. The serum titanium levels were higher in the titanium group at all follow-up time intervals as compared with the levels in all other groups, and the level in the titanium group at 120 months was eighteen times higher than it was at baseline (p < 0.01). Patients with well-functioning primary metal-on-polyethylene total hip replacements had elevated serum metal levels for as many as ten years postoperatively. Furthermore, metal release at the modular femoral head-neck junctions, rather than passive dissolution from porous ingrowth surfaces, was likely the dominant source of serum cobalt and chromium. Level of Evidence: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence. PMID:23515985
Levine, Brett R.; Hsu, Andrew R.; Skipor, Anastasia K.; Hallab, Nadim J.; Paprosky, Wayne G.; Galante, Jorge O.; Jacobs, Joshua J.
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.
We determined the effect of pre-operative bone structure upon the temporal effects of remodeling after total hip arthroplasty (THA) in a series of uncemented implants. We evaluated 345 patients (375 hips), who had either Dorr Type-A (238 hips) or Type-B (137 hips) bone, and who received a proximally-coated cementless THA and were followed for a mean of 6 years. Outcomes evaluated included aseptic survivorship, Harris hip scores, and radiographic evaluation for patterns of remodeling. The aseptic survivorship (97.5% vs. 98%) and the mean final Harris hip scores (92 vs. 94 points) were similar between Types-A and -B bone, respectively. Bone remodeling was seen significantly earlier and over a longer duration for patients who had Type-B bone. At 5-years, periprosthetic condensation (78% vs. 54%) and cortical hypertrophy (53% vs. 37%) were significantly higher and radiolucencies at any zone were lower (53% vs. 37%) in Type-B compared to Type-A bone. There was increased condensation in men and higher cortical hypertrophy in women. Various radiographic remodeling differences may not negatively impact clinical outcome at mid-term follow-up. Morphologic bone type appears to be predictive of physiologic response to loading. PMID:24838949
Issa, Kimona; Stroh, Alex D; Mont, Michael A; Bonutti, Peter M
Hip fractures represent the most severe complication of osteoporosis from the perspectives of the patient, carer, health care system and society. Given the strong association with age, numbers are set to rise significantly in the next few decades despite evidence that the age adjusted rates in some countries are either plateauing or falling. Given the almost invariable need for inpatient admission, hospital administrative data for hip fractures remain a robust measure of number of hip fractures in the community and can be extrapolated to determine the total expected number of clinical fragility fractures from the same population. Both process and outcome standards have now been developed to benchmark clinical quality in the care of patients with hip fractures and fragility fractures at other sites. PMID:24836330
Kassim Javaid, M; Chana, Jasroop; Cooper, Cyrus
Hip prosthesis stems with a short stem length and proximal fixation geometry support a bone-preserving and muscle-sparing implantation and should also allow for revision surgery with a standard hip stem. We present 250 prospectively documented clinical and radiological results from the Metha Short Hip Stem prosthesis (B. Braun-Aesculap, Tuttlingen, Germany) after an average follow-up of 4.9 years. The average patient age at surgery was 60 years. Indication for total hip replacement was primary osteoarthrosis (OA) (78% of patients), OA based on developmental dysplasia of the hip (16%), and other indications (6%). At the last follow-up, the average Harris Hip Score was 97 points. 85% of patients were very satisfied and 14% were satisfied after surgery, whereas 1% were dissatisfied. Pain according to the Visual Analogue Scale improved from 7.4 (min 1.6, max 9.5) pre-operatively to 0.23 (min 0, max 6.6). No joint dislocations occurred when predominantly using 28 mm and 32 mm prosthesis heads. Nine short-stems were revised: three after bacterial infections, two after primary via valsa with penetration of the femoral cortex two and three months after surgery, and three after early aseptic cases of loosening within the first year. A further nine osseously consolidated short-stems had to be replaced due to breakage of the modular titanium cone adapter after an average of 3.1 years (min 1.9, max 4.4). All surgical revisions were performed using primary standard stems. Without taking the material-related adapter failures into account, a five year Kaplan-Meier survival rate of 96.7% (95% confidence interval 93.4–98.3) was determined for the short-stem prostheses. There were no radiological signs of loosening in any of the short-stem prostheses at the last examination. Fine sclerotic lines were detected in Gruen's AP zones 1 (19%) and 2 (10.5%), individual hypertrophies in zone 3 (3.5%), fine seams in zones 4 (5.5%) and 5 (4%), without pedestal formations in zone 4, clear cancellous bone compressions in zone 6 (97.5%), as well as single fine scleroses (1.5%) and atrophies (2.5%) in zone 7. The mid-term clinical results with periprosthetic bone remodeling and without radiological signs of loosening confirm this metaphyseal short-stem treatment and fixation concept and the possibility of revision surgery using standard hip stems. Long-term results must be further observed on a prospective basis as part of this collective study. PMID:23705062
Wittenberg, Ralf H.; Steffen, Reinhard; Windhagen, Henning; Bucking, Petra; Wilcke, Andreas
We cloned and sequenced the Vicia sativa 25S-18S rDNA intergenic spacer (IGS) and the satellite repeat S12, thought to be related to the spacer sequence. The spacer was shown to contain three types of subrepeats (A, B, and C) with monomers of 173 bp (A), 10 bp (B), and 66 bp (C), separated by unique or partially duplicated sequences. Two spacer variants were
Ji?i Macas; Alice Navrátilová; Tibor Mészáros
More than 60,000 people worldwide use cochlear implants as a means to restore functional hearing. Although individual performance variability is still high, an average implant user can talk on the phone in a quiet environment. Cochlear-implant research has also matured as a field, as evidenced by the exponential growth in both the patient population and scientific publication. The present report examines current issues related to audiologic, clinical, engineering, anatomic, and physiologic aspects of cochlear implants, focusing on their psychophysical, speech, music, and cognitive performance. This report also forecasts clinical and research trends related to presurgical evaluation, fitting protocols, signal processing, and postsurgical rehabilitation in cochlear implants. Finally, a future landscape in amplification is presented that requires a unique, yet complementary, contribution from hearing aids, middle ear implants, and cochlear implants to achieve a total solution to the entire spectrum of hearing loss treatment and management. PMID:15247993
The aim of this study was to identify and characterise learning curves in hip fracture surgery. Operating times were collected\\u000a and related to the number of procedures done by residents performing closed reduction and internal fixation using cannulated\\u000a screws for intracapsular fractures of the hip and cephalomedullary nailing for trochanteric fractures, as well as hemiarthroplasty\\u000a for displaced intracapsular fractures. The
Kristian Bjorgul; Wendy M. Novicoff; Khaled J. Saleh
of the hip joint Approach: Acetabular rim syndrom Â· Early diagnostic of abnormal impingements Â· Surgery (Adduction) RTy (int rotation) RTz (flexion) -25 -20 -15 -10 -5 0 5 10 15 20 25 30 1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 RTx (Adduction) RTy (int rotation) RTz (flexion) Measurement of the hip
Background Physical activity in old age probably protects against hip fracture. However, very little is known about the impact of occupation during working life, in terms of its physical activity level and the socio-economic status (SES) it indicates, on the risk of hip fracture in later life. Method A population-bas ed case-control study was con- ducted on 416 subjects to
Lorna Kwai; Ping Suen
Increasing number of older patients are admitted to hospital with hip fractures. This review evaluates the common medical\\u000a problems that arise as a consequence of having a hip fracture. Older patients with fractures commonly have co-morbidities\\u000a that require evaluation prior to and after surgery. Joint acute orthopaedic–geriatric units have been established to provide\\u000a comprehensive orthopaedic and medical care with some
Carol Pei Wei Chong; Judith A. Savige; Wen Kwang Lim
A group of 42 primary total hip arthroplasties performed through an abridged surgical incision (group 1) was prospectively compared to a cohort of 42 primary total hip arthroplasties performed through a standard surgical incision (group 2). The length of the incision was 8.8 ± 1.5 cm for group 1 and 23.0 ± 2.1 cm for group 2. The groups were
John M Wright; Heber C Crockett; Sam Delgado; Stephen Lyman; Mike Madsen; Thomas P Sculco
We present the case of a 39-year-old man with bilateral piriformis syndrome 4 and 6 years after two cementless total hip\\u000a arthroplasties, respectively. During surgical exploration, each sciatic nerve was found to be entrapped by a tense piriformis\\u000a muscle and hypertrophic posterior hip capsule. The sciatic-type pain was relieved after sectioning each piriformis muscle\\u000a with external neurolysis. This is the
Y. Uchio; U. Nishikawa; M. Ochi; N. Shu; K. Takata
Background We studied which factor could predict aseptic loosening in ABG I hip prosthesis with hydroxyapatite coating. Aseptic loosening and periprosthetic osteolysis are believed to be caused, at least in part, by increased polyethylene (PE) wear rate via particle disease. Based on it, increased PE wear rate should be associated with aseptic loosening regardless of the type of implant. Methods We analyzed data from 155 revisions of ABG I hip prostheses to examine the influence of patient, implant, surgery, and wear related factors on the rate of aseptic loosening at the site of the cup. This was calculated by stepwise logistic regression analysis. The stability of the implant and severity of bone defects were evaluated intraoperatively. Results We found that men (odds ratio, OR = 5.6; p = 0.004), patients with Charnley class C (OR = 6.71; p = 0.013), those having more severe acetabular bone defects (OR = 4 for each degree of severity; p = 0.002), and longer time to revision surgery (OR = 1.51 for each additional year; p = 0.012) had a greater chance of aseptic loosening of the cup. However, aseptic loosening was not directly predicted by polyethylene wear rate in our patients. Conclusion Severity of bone defects predicts the risk for aseptic loosening in ABG I cup. Factors potentially associated with the quality of bone bed and biomechanics of the hip might influence on the risk of aseptic loosening in this implant. PMID:20959001
After total hip arthroplasty (THA) some patients have persistent postoperative pain (POP). Some of these POP are anterior and are caused by an anterior iliopsoas impingement (AIPI). We have hypothesized that oversized implanted cups could be responsible for POP and especially AIPI. We screened 237 patients who had a primary THA and compared the size difference (?S) between the native femoral head and the implanted cup, in patients with and without POP. Median ?S was 2 mm [-6; 11 mm] and patients with POP had a significantly increased ?S (P < 0.0001). The threshold above which pain was significantly more frequent was ?S ? 6 mm. Odds ratio was 14.4 for POP and 26 for AIPI pain when ?S ? 6 mm. PMID:23927907
Odri, Guillaume A; Padiolleau, Giovany B; Gouin, François T
The number of septic and aseptic total hip arthroplasty (THA) revisions will increase, which involves a greater financial burden. We here provide a retrospective consecutive analysis of the major variable direct costs involved in revision THA for aseptic and septic failure. A total of 144 patients (30 septic, 114 aseptic) treated between January 1, 2009 and March 31, 2012 was included. The management of septic THA loosening is much more expensive than that of aseptic loosening ($14,379.8 vs. $5,487.4). This difference is mainly attributable to the two-stage exchange technique used for septic failure (hospital stay: 40.2 vs. 15.6 days) and significantly higher implant costs ($3,930.9 vs. $2,298.2). The septic implantation part is on average $3,384.6 more expensive than aseptic procedures (P < .001). PMID:24927869
Assmann, Grit; Kasch, Richard; Maher, Christopher G; Hofer, André; Barz, Thomas; Merk, Harry; Flessa, Steffen
? Over the past decade, porous tantalum has emerged as a powerful tool for reconstruction of the failed acetabular component.? The increased porosity, high coefficient of friction, and favorable elastic modulus of porous tantalum compared with traditional titanium mesh or cobalt chromium acetabular components allow for greater bone ingrowth potential, implant stability, and host bone preservation, respectively, in porous tantalum shells.? Several studies have confirmed the excellent early and midterm results of porous tantalum reconstruction for revision hip arthroplasty.? Depending on the degree of bone loss, excellent results have been achieved with modular or revision porous tantalum shells, tantalum shells with tantalum augments, and cup-cage constructs.? These implants and techniques are greatly changing the approach to acetabular revision surgery and are providing constructs with greater stability and more physiologic biomechanical properties than those achieved through the use of traditional reconstructive methods. PMID:24196469
Issack, Paul S
This prospective study was designed to evaluate 196 Anatomique Benoist Giraud (ABG II) total hip arthroplasties which were implanted between September 1999 and December 2000. A minimum 11 years follow up was completed in 183 cases. The bearing surfaces were polyethylene-zirconia in 84 cases, polyethylene-metal in 42 and ceramic-ceramic in 57. Changes in the femoral stem design, in relation to the previous ABG I model, have led to a significant improvement in stress-shielding. Polyethylene wear rate was lower by more than 50% compared with non-crosslinked polyethylene. Excellent and good results were obtained in 90.32% of cases, and implant survival was 98.39% at the end of follow-up. PMID:23134598
Herrera, Antonio; Mateo, Jesús; Lobo-Escolar, Antonio; Panisello, Juan José; Ibarz, Elena; Gracia, Luis
Background and purpose It has been speculated that the prevalence of metal allergy may be higher in patients with implant failure. We compared the prevalence and cause of revisions following total hip arthroplasty (THA) in dermatitis patients suspected to have contact allergy and in patients in general with THA. Furthermore, we compared the prevalence of metal allergy in dermatitis patients with and without THA. Materials and methods The Danish Hip Arthroplasty Registry (DHAR) contained detailed information on 90,697 operations. The Gentofte patch-test database contained test results for patients suspected of having allergic contact dermatitis (n = 18,794). Cases (n = 356) were defined as patch-tested dermatitis patients who also had primary THA performed. Two age- and sex-matched controls (n = 712) from the patch-test database were sought for each case. Results The prevalence of revision was similar in cases (12%) and in patients from the DHAR (13%). The prevalence of metal allergy was similar in cases and controls. However, the prevalence of metal allergy was lower in cases who were patch-tested after operation (6%) than in those who were patch-tested before operation (16%) (OR = 2.9; 95% CI = 1–8). Interpretation We found that the risk of surgical revision was not increased in patients with metal allergies and that the risk of metal allergy was not increased in cases who were operated, in comparison to controls. Despite some important study limitations, our observations add to the evidence that the risk of complications in metal allergic patients seems limited. PMID:19995314
The Charnley low-friction arthroplasty was performed on 73 hips in 55 patients with inflammatory joint disease, usually for intolerable pain. Sixty-five of these operations were reviewed at a special clinic or by postal questionnaire; 57 hips were painfree or gave rise to only occasional discomfort, in 58 there was an increased range of movement, and in 46 of the 59
Jacqueline Harris; C. D. R. Lightowler; R. C. Todd
The goal of this paper was to determine the effectiveness of the HIP HOP for HIV Awareness intervention, an innovative model utilising an exchange of an HIV test for a hip hop concert ticket, in a metropolitan city among African American youth and young adults. A subset of intervention participants participated in standardised testing, sex…
Hill, Mandy J.; Hallmark, Camden J.; McNeese, Marlene; Blue, Nike; Ross, Michael W.
We report the presence, in the mitochondrial DNA (mtDNA) of all of the sexual species of the salamander family Ambystomatidae, of a shared 240-bp intergenic spacer between tRNAThr and tRNAPro. We place the intergenic spacer in context by presenting the sequence of 1,746 bp of mtDNA from Ambystoma tigrinum tigrinum, describe the nucleotide composition of the intergenic spacer in all of the species of Ambystomatidae, and compare it to other coding and noncoding regions of Ambystoma and several other vertebrate mtDNAs. The nucleotide substitution rate of the intergenic spacer is approximately three times faster than the substitution rate of the control region, as shown by comparisons among six Ambystoma macrodactylum sequences and eight members of the Ambystoma tigrinum complex. We also found additional inserts within the intergenic spacers of five species that varied from 87-444 bp in length. The presence of the intergenic spacer in all sexual species of Ambystomatidae suggests that it arose at least 20 MYA and has been a stable component of the ambystomatid mtDNA ever since. As such, it represents one of the few examples of a large and persistent intergenic spacer in the mtDNA of any vertebrate clade. PMID:9364774
McKnight, M L; Shaffer, H B
Study Design Controlled laboratory cross-sectional study. Objectives To assess strength differences of the hip rotator and abductor muscle groups in young adults with chronic hip joint pain (CHJP) and asymptomatic controls. A secondary objective was to determine if strength in the uninvolved hip of those with unilateral CHJP differs from that in asymptomatic controls. Background Little is known about the relationship between hip muscle strength and CHJP in young adults. Methods Thirty-five participants with CHJP and 35 matched controls (18 to 40 years of age) participated. Using handheld dynamometry, strength of the hip external rotators and internal rotators was assessed with the hip flexed to 90° and 0°. To assess external rotator and internal rotator strength, the hip was placed at the end range of external rotation and internal rotation, respectively. Strength of the hip abductors was assessed in sidelying, with the hip in 15° of abduction. Break tests were performed to determine maximum muscle force, and the average torque was calculated using the corresponding moment arm. Independent-sample t tests were used to compare strength values between (1) the involved limb in participants with CHJP and the corresponding limb in the matched controls, and (2) the uninvolved limb in participants with unilateral CHJP and the corresponding limb in the matched controls. Results Compared to controls, participants with CHJP demonstrated weakness of 16% to 28% (P<.01) in all muscle groups tested in the involved hip. The uninvolved hip of 22 subjects with unilateral CHJP demonstrated weakness of 18% and 16% (P<.05) in the external rotators (0°) and abductors, respectively, when compared to the corresponding limb of the matched controls. Conclusion The results of the present study demonstrate that persons with CHJP have weakness in the hip rotator and hip abductor muscles. Weakness also was found in the uninvolved hip of persons with CHJP. J Orthop Sports Phys Ther 2014;44(11):890-898. Epub 9 October 2014. doi:10.2519/jospt.2014.5268. PMID:25299750
Harris-Hayes, Marcie; Mueller, Michael J; Sahrmann, Shirley A; Bloom, Nancy J; Steger-May, Karen; Clohisy, John C; Salsich, Gretchen B
Background Vertebrate mitogenomes are economically organized and usually lack intergenic sequences other than the control region. Intergenic spacers located between the tRNAThr and tRNAPro genes (“T-P spacers”) have been observed in several taxa, including gadiform species, but information about their biological roles and putative functions is still lacking. Results Sequence characterization of the complete European hake Merluccius merluccius mitogenome identified a complex T-P spacer ranging in size from 223–532 bp. Further analyses of 32 gadiform species, representing 8 families and 28 genera, revealed the evolutionary preserved presence of T-P spacers across all taxa. Molecular complexity of the T-P spacers was found to be coherent with the phylogenetic relationships, supporting a common ancestral origin and gain of function during codfish evolution. Intraspecific variation of T-P spacer sequences was assessed in 225 Atlantic cod specimens and revealed 26 haplotypes. Pyrosequencing data representing the mito-transcriptome poly (A) fraction in Atlantic cod identified an abundant H-strand specific long noncoding RNA of about 375 nt. The T-P spacer corresponded to the 5’ part of this transcript, which terminated within the control region in a tail-to-tail configuration with the L-strand specific transcript (the 7S RNA). Conclusions The T-P spacer is inferred to be evolutionary preserved in gadiform mitogenomes due to gain of function through a long noncoding RNA. We suggest that the T-P spacer adds stability to the H-strand specific long noncoding RNA by forming stable hairpin structures and additional protein binding sites. PMID:25145347
Ceramic bearing surfaces are increasingly used for total hip replacement, notwithstanding that concern is still related to ceramic brittleness and its possible mechanical failure. The aim of this systematic review is to answer three questions: (1) Are there risk factors for ceramic component fracture following total hip replacement? (2) Is it possible to perform an early diagnosis of ceramic component failure before catastrophic fracture occurs? (3) Is it possible to draw guidelines for revision surgery after ceramic components failure? A PubMed and Google Scholar search was performed and reference citations from publications identified in the literature search were reviewed. The use of 28?mm short-neck femoral head carries an increased risk of fracture. Acetabular component malposition might increase the risk of ceramic liner fractures. Synovial fluid microanalysis and CT scan are promising in early diagnosis of ceramic head and liner failure. Early revision is suggested in case of component failure; no consensus exists about the better coupling for revision surgery. Ceramic brittleness remains a major concern. Due to the increased number of ceramic on ceramic implants, more revision surgeries and reports on ceramic components failure are expected in the future. An algorithm of diagnosis and treatment for ceramic hip failure is proposed. PMID:23844356
Traina, Francesco; Faldini, Cesare
Migration of solid corrosion products from the modular head-neck junction of fifteen total hip replacements to the periprosthetic tissues was studied. The devices and tissues were recovered at the time of a revision procedure or at autopsy after a mean of sixty-four months (range, eight to ninety-seven months). The prostheses had a cobalt-chromium-alloy head coupled with a cobalt-chromium-alloy or a titanium-alloy stem. The solid corrosion product was identified by electron microprobe analysis and Fourier transform infrared microprobe spectroscopy as a chromium orthophosphate hydrate-rich material. The product was present at the junction of the modular head and neck and as particles within the periprosthetic tissues as early as eight months postoperatively. In several hips, it was also present on the polyethylene bearing surface. The particles in the tissues ranged in size from less than one to 500 micrometers. They were present within histiocytes or were surrounded by foreign-body giant cells in the pseudocapsule of the hip joint; in the membranes of the femoral bone-implant interface; and at sites of femoral endosteal erosions, with and without loosening of the femoral component. PMID:8077264
Urban, R M; Jacobs, J J; Gilbert, J L; Galante, J O
Background: Patients undergoing cemented hip hemiarthroplasty may develop bone cement implantation syndrome (BCIS) which is a leading cause of intraoperative complications. The purpose of this study was to evaluate cardiovascular changes during cemented hip hemiarthroplasty in elderly patients. Methods: Cemented hip hemiarthroplasty was performed on 72 patients with femoral neck fracture. All patients were catheterized with a radial artery catheter to assess mean arterial pressure (MAP) and arterial blood gas (ABG) in these time points: just before cementation, just after cementation (0th), 5 min (5th) and 10 min (10th) after cementation, and at the end of surgery (END). Also, systolic and diastolic blood pressure (SBP & DBP), heart rate and any arrhythmia or cardiac arrest was evaluated. Results: Seventy-two patients (33 females, 39 males; mean age: 66.8±7 years) were evaluated. All parameters changed during cementation with a significant drop in MAP, SBP, and DBP immediately after cementation and pH and base excess decreased significantly (P<0.001) with no changes in O2 saturation. Mean heart rate rose until the 5th and then decreased dramatically with no bradycardia presentation. During cementation, 12 patients showed arrhythmia, but no cardiac-arrest was observed. Conclusions: Under strict observation of a anesthesiology care team, hemiarthroplasty can be a safe method for femoral neck fracture in elderly osteoporotic patients without severe cardiopulmonary compromise. PMID:25386576
Soleimanha, Mehran; Sedighinejad, Abbas; Haghighi, Mohammad; Nabi, Bahram Naderi; Mirbolook, Ahmad Reza; Mardani-Kivi, Mohsen
The object of making an impression in implant dentistry is to accurately relate an analogue of the implant or implant abutment to the other structures in the dental arch. This is affected by use of an impression coping which is attached to the implant or implant abutment. This impression coping is incorporated in an impression – much as a metal
S Jivraj; W Chee
Background and purpose In a previous study based on the Finnish Arthroplasty Register, the survival of cementless stems was better than that of cemented stems in younger patients. However, the survival of cementless cups was poor due to osteolysis. In the present study, we analyzed population-based survival rates of the cemented and cementless total hip replacements in patients under the age of 55 years with primary osteoarthritis in Finland. Patients and methods 3,668 implants fulfilled our inclusion criteria. The previous data included years 1980–2001, whereas the current study includes years 1987–2006. The implants were classified in 3 groups: (1) implants with a cementless, straight, proximally circumferentially porous-coated stem and a porous-coated press-fit cup (cementless group 1); (2) implants with a cementless, anatomic, proximally circumferentially porous-coated stem, with or without hydroxyapatite, and a porous-coated press-fit cup with or without hydroxyapatite (cementless group 2); and (3) a cemented stem combined with a cemented all-polyethylene cup (the cemented group). Analyses were performed separately for 2 time periods: those operated 1987–1996 and those operated 1997–2006. Results The 15-year survival for any reason of cementless total hip replacement (THR) group 1 operated on 1987–1996 (62%; 95% CI: 57–67) and cementless group 2 (58%; CI: 52–66) operated on during the same time period was worse than that of cemented THRs (71%; CI: 62–80), although the difference was not statistically significant. The revision risk for aseptic loosening of cementless stem group 1 operated on 1987–1996 (0.49; CI: 0.32–0.74) was lower than that for aseptic loosening of cemented stems (p = 0.001). Interpretation Excessive wear of the polyethylene liner resulted in numerous revisions of modular cementless cups. The outcomes of total hip arthroplasty appear to have been relatively unsatisfactory for younger patients in Finland. PMID:21992084
Cell Cultures Cotransformed with dCas9 and sgRNA, Related to Figure 2 (A) Transformation efficiency for transforming E. coli cells with two plasmids. One plasmid contains an sgRNA that targets to a genomic copy of m but not the template DNA strand (T1). Also, silencing is highly specific, as a GFP-specific sgRNA (gfp) shows no effect
X-ray Computed Tomography (CT) is a relatively new technique developed in the late 1970's, which enables the nondestructive visualization of the internal structure of objects. Beam hardening caused by the polychromatic spectrum is an important problem in X-ray computed tomography (X-CT). It leads to various artifacts in reconstruction images and reduces image quality. In the present work we are considering the Artifact Reduction in Total Hip Prosthesis CT Scan which is a problem of medical imaging. We are trying to reduce the cupping artifact induced by beam hardening as well as metal artifact as they exist in the CT scan of a human hip after the femur is replaced by a metal implant. The correction method for beam hardening used here is based on a previous work. Simulation study for the present problem includes a phantom consisting of mild steel, aluminium and perspex mimicking the photon attenuation properties of a hum hip cross section with metal implant.
Madhogarhia, Manish [Nuclear Engineering and Technology Programme, Indian Institute of Technology, Kanpur 208016 (India); Munshi, P.; Lukose, Sijo; Subramanian, M. P.; Muralidhar, C. [Non Destructive Evaluation Division, Defence Research and Development Laboratory, Hyderabad 500258 (India)
Reports of differing failure rates of total hip prostheses made of various metals prompted us to measure the size of metallic and polyethylene particulate debris around failed cemented arthroplasties. We used an isolation method, in which metallic debris was extracted from the tissues, and a non-isolation method of routine preparation for light and electron microscopy. Specimens were taken from 30 cases in which the femoral component was of titanium alloy (10), cobalt-chrome alloy (10), or stainless steel (10). The mean size of metallic particles with the isolation method was 0.8 to 1.0 microns by 1.5 to 1.8 microns. The non-isolation method gave a significantly smaller mean size of 0.3 to 0.4 microns by 0.6 to 0.7 microns. For each technique the particle sizes of the three metals were similar. The mean size of polyethylene particles was 2 to 4 microns by 8 to 13 microns. They were larger in tissue retrieved from failed titanium-alloy implants than from cobalt-chrome and stainless-steel implants. Our results suggest that factors other than the size of the metal particles, such as the constituents of the alloy, and the amount and speed of generation of debris, may be more important in the failure of hip replacements.
Lee, J. M.; Salvati, E. A.; Betts, F.; DiCarlo, E. F.; Doty, S. B.; Bullough, P. G.
As wear is inevitable with artificial joint replacement, it has to be minimized to avoid possible aseptic loosening following osteolysis due to particle-initiated foreign body reaction. Co-Cr-Mo-C alloys have a long history with only minimum wear when articulating with themselves. This investigation shows that the choice of the alloy has an effect on the wear rate of this articulation couple. Tribological studies in a screening device, a pendulum apparatus and a hip joint simulator showed a marked influence of the environment as well as the diameter of the implants with metal-on-metal articulation. A wear-resistant combination with low friction characteristics has been developed by using a wrought Co-Cr-Mo-C alloy and reducing the implant diameter to 28 mm. Clinical wear rates are comparable with laboratory data and demonstrate the potential of the metal-on-metal articulation to solve the problem of wear-induced osteolysis of hip joint endoprostheses. PMID:8885660
Streicher, R M; Semlitsch, M; Schön, R; Weber, H; Rieker, C
Total hip replacement is considered to be a highly successful and routine surgery; however, the internal components produce particles through friction and wear in the device. These particles are identified as one of the main reasons for total hip revisions. The generated, biologically active, particles provoke the formation of osteolytic areas through the inhibition of bone formation and increased fluid production. The resulting bone loss can be managed through the use of allograft bone in combination with bone chips and cement. In addition, implants constructed with highly porous trabecular metal can be used to further facilitate rapid and extensive tissue infiltration resulting in strong implant attachment. In this case study we show the use of a tibial allograft coupled with bone chips and cement to cover and support a lytic cyst in the proximal femur, distal to the greater trochanter. Additionally, we detail the use of a trabecular metal cup to halt the migration of the component into the acetabulum and promote greater fixation and bone ingrowth. PMID:19753282
Taylor, Drew W; Taylor, Jennifer E; Raizman, Igal; Gross, Allan E
We investigate photoluminescence (PL) properties of quasi-monolayered tetraphenyl porphyrin (TPP) molecules on silicon substrates modulated by three different nanoscale spacers: native oxide layer (NOL), hydrogen (H)-passivated layer, and Ag nanoparticle (AgNP) thin film, respectively. In comparison with the PL intensity from the TPP molecules on the NOL-covered silicon, the fluorescence intensity from the molecules on the AgNP-covered surface was greatly enhanced while that for the H-passivated surface was found dramatically suppressed. Time-resolved fluorescence spectra indicated shortened lifetimes for TPP molecules in both cases, but the decay kinetics is believed to be different. The suppressed emission for the H-passivated sample was attributed to the weaker decoupling effect of the monolayer of hydrogen atoms as compared to the NOL, leading to increased nonradiative decay rate; whereas the enhanced fluorescence with shortened lifetime for the AgNP-covered sample is attributed not only to the resonant excitation by local surface plasmons, but also to the increased radiative decay rate originating from the emission enhancement in plasmonic "hot-spots".
Fang, Y. C.; Zhang, Y.; Gao, H. Y.; Chen, L. G.; Gao, B.; He, W. Z.; Meng, Q. S.; Zhang, C.; Dong, Z. C.
AIMS—To develop and implement an evidence based guideline for the treatment of acute asthma using a metered dose inhaler and spacer combination.?METHODS—Defined strategies were used for the development and implementation of a guideline, assessed by a prospective, descriptive, study using notes review, and patient, nursing, and medical staff telephone contact. The setting was a tertiary referral hospital in Victoria, Australia with 25 000 yearly admissions, and asthma accounting for about 7% of total. The first 200 children and families to use the guideline after its introduction were evaluated.?RESULTS—A total of 191 (95.5%) children were treated according to the guideline. Six (3.0%) children were given nebulisers appropriately based on severity; five (2.5%) were given nebulisers at parental or child choice; and four (2.0 %) who did not have severe asthma, received nebulised treatment inappropriately.?CONCLUSIONS—Successful implementation of a new evidence based guideline can be achieved using specific strategies for promoting the application of research findings in the clinical arena.?? PMID:11159290
Powell, C; Maskell, G; Marks, M; South, M; Robertson, C; LENNEY, W.
Nuclear rDNA Internal Transcribed Spacers, ITS1 and ITS2, are widely used for eukaryote phylogenetic studies from the ordinal level to the species level, and there is even a database for ITS2 sequences. However, ITS regions have been ignored in mammalian phylogenetic studies, and only a few rodent and ape sequences are represented in GenBank. The reasons for this dearth, and the remedies, are described here. We have recovered these sequences, mostly >1 kb in length, for 36 mammalian species. Sequence alignment and transcript folding comparisons reveal the rRNA transcript secondary structure. Mammalian ITS regions, though quite long, still fold into the recognizable secondary structure of other eukaryotes. The ITS2 in particular bears the four standard helix loops, and loops II and III have the hallmark characters universal to eukaryotes. Both sequence and insertions/deletions of transcript secondary structure helices observed here support the four superorder taxonomy of Placentalia. On the family level, major unique indels, neatly excising entire helices, will be useful when additional species are represented, resulting in significant further understanding of the details of mammalian evolutionary history. Furthermore, the identification of a highly conserved element of ITS1 common to warm-blooded vertebrates may aid in deciphering the complex mechanism of RNA transcript processing. This is the last major group of terrestrial vertebrates for which rRNA ITS secondary structure has been resolved. PMID:24260162
Coleman, Annette W.
Identification of Acinetobacter spp. to the DNA group level by phenotypic techniques is problematic, and there is a need for an alternative identification method for routine use. The present study validated the suitability of a rapid identification technique based on tRNA spacer (tDNA) fingerprinting in comparison with that of a commercially available assay involving carbon source utilization tests (Biolog MicroStation System) for identifying the 21 DNA-DNA hybridization groups belonging to the genus. For this purpose, 128 strains identified previously by DNA-DNA hybridization were analyzed by both techniques. tDNA fingerprinting was highly reproducible and classified all strains into 17 groups. Six DNA groups belonging to the A. calcoaceticus-A. baumannii complex were grouped into two distinct clusters, indicating the high degree of genetic similarity within this complex. Strains of the more recently described DNA groups BJ13 to BJ16 were ambiguously grouped and displayed three pattern types. The software used with the commercial carbon source utilization method grouped the 128 strains into 12 clusters, explaining the less discriminatory power of this system. We conclude that tDNA fingerprinting offers a quick and reliable method for the routine differentiation of most Acinetobacter spp. at the subgenus level. PMID:8880491
Ehrenstein, B; Bernards, A T; Dijkshoorn, L; Gerner-Smidt, P; Towner, K J; Bouvet, P J; Daschner, F D; Grundmann, H
... sponsored Research Shows Cataract Surgery Can Reduce Hip Fracture Risk 08/01/2012 09:00:00 AM ... Medicare beneficiaries shows that the risk of hip fractures was significantly reduced in patients who had had ...
A gas turbine rotor stacking fixture includes upstanding bolts for reception in aligned bolt holes in superposed aft disk, wheels and spacers and upstanding alignment rods received in openings of the disk, wheels and spacers during the rotor stacking assembly. The axially registering openings enable insertion of thin-walled tubes circumferentially about the rim of the rotor, with tight tolerances to the openings to provide supply and return steam for cooling buckets. The alignment rods have radial dimensions substantially less than their dimensions in a circumferential direction to allow for radial opening misalignment due to thermal expansion, tolerance stack-up and wheel-to-spacer mismatch due to rabbet mechanical growth. The circumferential dimension of the alignment rods affords tightly toleranced alignment of the openings through which the cooling tubes are installed.
Berry, Robert Randolph (Greenville, SC); Palmer, Gene David (Clifton Park, NY); Wilson, Ian David (Clifton Park, NY)
Bone loss around femoral hip stems is one of the problems threatening the long-term fixation of uncemented stems. Many believe that this phenomenon is caused by reduced stresses in the bone (stress shielding). In the present study the mechanical consequences of different femoral stem materials were investigated using adaptive bone remodeling theory in combination with the finite element method. Bone-remodeling in the femur around the implant and interface stresses between bone and implant were investigated for fully bonded femoral stems. Cemented stems (cobalt-chrome or titanium alloy) caused less bone resorption and lower interface stresses than uncemented stems made from the same materials. The range of the bone resorption predicted in the simulation models was from 23% in the proximal medial cortex surrounding the cemented titanium alloy stem to 76% in the proximal medial cortex around the uncemented cobalt-chrome stem. Very little bone resorption was predicted around a flexible, uncemented "iso-elastic" stem, but the proximal interface stresses increased drastically relative to the stiffer uncemented stems composed of cobalt-chrome or titanium alloy. However, the proximal interface stress peak was reduced and shifted during the adaptive remodeling process. The latter was found particularly in the stiffer uncemented cobalt-chrome-molybdenum implant and less for the flexible iso-elastic implant. PMID:1403299
Weinans, H; Huiskes, R; Grootenboer, H J
Stresses and strains are major factors influencing growth, remodeling and repair of musculoskeletal tissues. Therefore, knowledge of forces and deformation within bones and joints is critical to gain insight into the complex behavior of these tissues during development, aging, and response to injury and disease. Sensors have been used in vivo to measure strains in bone, intraarticular cartilage contact pressures, and forces in the spine, shoulder, hip, and knee. Implantable sensors have a high impact on several clinical applications, including fracture fixation, spine fixation, and joint arthroplasty. This review summarizes the developments in strain-measurement-based implantable sensor technology for musculoskeletal research. PMID:23369655
The AISI 316L stainless steel has been widely used both in artificial knee and hip joints in bio-medical applications. In the present study AISI 316L SS was implanted with two different ions: nitrogen and helium at 100keV with a dose of 1×1017ions\\/cm2 at room temperature. The crystallographic orientation and surface morphology were studied using X-ray diffraction (XRD) and scanning electron
V. Muthukumaran; V. Selladurai; S. Nandhakumar; M. Senthilkumar
One common complication following total-hip-replacement arthroplasty – one of the most performed elective surgical procedures – is the loosening of the prosthetic stem and cup, responsible for more than 80% of non-successes. A combination of piezoelectric and piezoresistive materials in a sensing device for dynamical and quasi-static analysis of the implant internal environment is envisaged by the authors. In this
P. Alpuim; S. A. Filonovich; C. Costa; P. F. Rocha; M. I. Vasilevskiy; S. Lancerosmendez; C. Frias; A. Torres Marques; R. Soares
We reviewed the results of 172 plasma-sprayed, titanium primary total hip arthroplasties inserted without cement and followed 5 to 7 years. Hips were replaced for a wide range of diagnoses and patient ages. No femoral components had been revised nor were any considered unstable. Clinical results have been excellent; 88% of hips had either no or slight amount of pain and only 5% of patients had thigh pain when specifically asked. Radiographically, this femoral component achieved stability after an initial subsidence in 9% of cases. Extensive femoral bone resorption was rare, and distal cortical hypertrophy was commonly seen. Pelvic osteolysis occurred in 16 (9%) cases and was considered major in 10 of these. It was the cause of failure of 3 acetabular components. Femoral endosteal lysis was not observed. We concluded that mechanical stability of the Mallory-Head titanium total hip prostheses is excellent. However, significant pelvic osteolysis had occurred commonly with this implant design, and will continue to pose major reconstructive problems in the future. Images Figure 5 Figure 7a Figure 7b Figure 7c Figures 8 a-b Figures 9 a-b Figures 10 a-b Figures 11a-d PMID:9129271
Mulliken, B. D.; Bourne, R. B.; Rorabeck, C. H.; Nayak, N.
OBJECTIVE--To test the hypothesis that farmers are at high risk of hip osteoarthritis and to investigate possible causes for such a hazard. DESIGN--Cross sectional survey. SETTING--Five rural general practices. SUBJECTS--167 male farmers aged 60-76 and 83 controls from mainly sedentary jobs. All those without previous hip replacement underwent radiography of the hip. MAIN OUTCOME MEASURES--Hip replacement for osteoarthritis or radiological
P. Croft; D. Coggon; M. Cruddas; C. Cooper
Radiographic evaluation provides essential information regarding the diagnosis and treatment of musculoskeletal disorders.\\u000a We evaluated the ability of hip specialists to reliably identify important radiographic features and to make a diagnosis based\\u000a on plain radiographs alone. Five hip specialists and one fellow performed a blinded radiographic review of 25 control hips,\\u000a 25 hips with developmental dysplasia (DDH), and 27 with
John C. Clohisy; John C. Carlisle; Robert Trousdale; Young-Jo Kim; Paul E. Beaule; Patrick Morgan; Karen Steger-May; Perry L. Schoenecker; Michael Millis
Sport and total hip arthroplasty (THA) have been regarded by many as being mutually exclusive. The primary indication for\\u000a hip arthroplasty has always been pain. With advances in the technology surrounding hip replacement surgery and increasing\\u000a patient expectations of what THA can offer, there is a growing demand for hip replacement with the aim of returning to sporting\\u000a activity. The
M. J. Wilson; R. N. Villar
The aim of this review is to evaluate the current available literature evidencing on peri-articular hip endoscopy (the third compartment). A comprehensive approach has been set on reports dealing with endoscopic surgery for recalcitrant trochanteric bursitis, snapping hip (or coxa-saltans; external and internal), gluteus medius and minimus tears and endoscopy (or arthroscopy) after total hip arthroplasty. This information can be used to trigger further research, innovation and education in extra-articular hip endoscopy. PMID:23610664
Verhelst, L; Guevara, V; De Schepper, J; Van Melkebeek, J; Pattyn, C; Audenaert, E A
Our purpose was to evaluate evidence regarding the effectiveness of open iliopsoas release and lengthening with arthroscopic approaches, which combine iliopsoas release with the treatment of intra-articular pathology as treatments for internal snapping hip syndrome. Searches were performed of 4 databases and 12 reports on the surgical treatment of internal snapping hip were reviewed. The authors tabulated data according to year of study, journal, study type, level of evidence, patient demographics, procedure, and outcomes. We found that surgical treatment of internal snapping hip improves patient symptoms in the majority of patients. Endoscopic release is associated with fewer reported complications compared with open release. All studies of endoscopic treatment of internal snapping hip syndrome also performed intra-articular examination and treatment of intra-articular pathology. The incidence of associated intra-articular pathology was reported in 5 of 6 studies. These results suggest that a painful snapping iliopsoas tendon in many cases may be a result of intra-articular hip pathology rather than an independent entity. Early studies suggest no difference in efficacy or associated complications rate when comparing extracapsular to transcapsular iliopsoas tendon release. Further studies are needed comparing operative to nonoperative treatment and methods of determining patients likely to benefit from operative intervention. PMID:23740339
Kroger, E W; Griesser, M J; Kolovich, G P; Ellis, T J
Using a rabbit model of methicillin-resistant Staphylococcus aureus knee-prosthesis infection, we studied the efficacy of teicoplanin cement alone or in combination with systemic intramuscular (i.m.) injections of teicoplanin. Seven days after infection, surgical debridement and removal of the infected prostheses were performed, and five rabbits were randomly assigned to one of five different treatment groups: untreated controls, prosthesis replacement by drug-free cement spacer, prosthesis replacement by teicoplanin-loaded cement spacer (1.2 g of teicoplanin/40 g of cement), i.m. injections of teicoplanin (20 mg/kg of body weight, twice a day for 7 days), or systemic antibiotic treatment combined with teicoplanin-loaded spacers. The most effective regimen combined systemic teicoplanin and antibiotic spacers. PMID:14506060
Ismael, Farid; Bleton, Remy; Saleh-Mghir, Azzam; Dautrey, Sophie; Massias, Laurent; Cremieux, Anne-Claude
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 (either the baseplate or the faceplate). A release agent is applied to the mold prior to precursor application to ease removal of the mold after formation of the dielectric spacer. The shrinkage of the gel during solvent extraction also improves mold removal. The final spacer material is a good dielectric, such as silica, secured to the substrate.
Bernhardt, Anthony F. (Berkeley, CA); Contolini, Robert J. (Pleasanton, CA)
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 the substrate (either the baseplate or the faceplate). A release agent is applied to the mold prior to precursor application to ease removal of the mold after formation of the dielectric spacer. The shrinkage of the gel during solvent extraction also improves mold removal. The final spacer material is a good dielectric, such as silica, secured to the substrate. 3 figs.
Bernhardt, A.F.; Contolini, R.J.
Viruses are the most abundant life-like entities on the planet Earth. Using CRISPR spacer sequences, we have developed a microarray-based approach to detecting viral signatures in the acidic hot springs of Yellowstone.
J. C. Snyder; M. M. Bateson; D. Suciu; M. J. Young
Novel woven spacer fabrics based on hybrid yarns are suitable for an efficient fabrication of three-dimensional composite structures in high volume production. In this paper, an innovative manufacturing process with short cycle times and high automatisation is introduced for textile-reinforced thermoplastic spacer structures suited for bending load cases. The different process steps hybrid yarn fabrication, weaving technology for three-dimensional textile preforms and consolidation with unique kinematics and hot pressing technology are described in detail. The bending properties of the manufactured spacer structures are evaluated by means of experiments as well as finite element simulations. Numerical parametric studies are performed in order to validate the influence of manufacturing tolerances on the bending stiffness of the spacer structures.
Hufenbach, Werner; Adam, Frank; Füßel, René; Krahl, Michael; Weck, Daniel
Deposition of microspheres mimicking bacterial cells was studied experimentally and with a numerical model in feed spacer membrane channels, as used in spiral wound nanofiltration (NF) and reverse osmosis (RO) membrane systems. In-situ microscopic observations in membrane fouling simulators revealed formation of specific particle deposition patterns for different diamond and ladder feed spacer orientations. A three-dimensional numerical model combining fluid flow with a Lagrangian approach for particle trajectory calculations could describe very well the in-situ observations on particle deposition in flow cells. Feed spacer geometry, positioning and cross-flow velocity sensitively influenced the particle transport and deposition patterns. The deposition patterns were not influenced by permeate production. This combined experimental-modeling approach could be used for feed spacer geometry optimization studies for reduced (bio)fouling. PMID:25055226
Radu, A I; van Steen, M S H; Vrouwenvelder, J S; van Loosdrecht, M C M; Picioreanu, C
generated in a fuel bundle with Spacer Grids (SG) and Mixing Vanes (MV). CFD calculations were performed using different turbulence models for steady state simulations. Large Eddy Simulations (LES) scheme was applied to time dependent cases. The simulations...
The authors examined 54 biopsies taken from the tissue surrounding loosened hip joint prostheses. In situ apoptotic cell identification was performed by the detection of single- and double-stranded DNA breaks that occurred in the early stages of apoptosis. Both types of breaks can be revealed by labeling the free 3'-OH termini with modified nucleotides (fluoresceine-dUTP) in an enzymatic reaction catalyzed by terminal deoxynucleotidyl transferase (TdT). Results were correlated with the presence of wear debris in the tissue and with the use of bone cement for prosthesis fixation. Apoptotic cells were present in a higher percentage in tissue sections where metal particles were present (24% apoptotic cells) if compared to areas where no wear (6%), or plastic wear (2.8%) or ceramic wear (1.5%) was observed. Apoptosis is neither related to bone cement, nor to the time it takes for the implant to fail. Cell death by apoptosis may be important in implants which release metal ions by corrosion or wear and may have been underestimated up to now, as it is a 'clean' way of cell death, leading to limited damage in the surrounding tissues. PMID:10850934
Stea, S; Visentin, M; Granchi, D; Cenni, E; Ciapetti, G; Sudanese, A; Toni, A
Background: Spontaneous hip lateralization complicates the management of non-ambulatory children with cerebral palsy (CP). It can be diagnosed early using radiographs, but it involves standardization of positioning and exposure to radiation. Hence, the aim of this study was to assess the utility of Combined hip abduction angle (CHAA) in the clinical setting to identify those children with CP who were at greater risk to develop spontaneous progressive hip lateralization. Materials and Methods: One hundred and three children (206 hips) with CP formed our study population. There were 48 boys and 55 girls aged 2–11 years (mean 5.03 years). 61 children were Gross Motor Function Classification System (GMFCS) level 5, while 42 were GMFCS level 4. Clinical measurements of CHAA were statistically correlated with radiographic measurements of Reimer's migration percentage (MP) for bivariate associations using ?2 and t tests. Results: CHAA is evaluated against MP which is considered as a reliable measure of hip subluxation. Thus, for CHAA, sensitivity was 74.07% and specificity was 67.35%. False-positive rate was 32.65% and false-negative rate was 25.93%. Conclusions: Our study shows that correlation exists between CHAA and MP, which has been proved to be useful for hip screening in CP children at risk of hip dislocation. CHAA is an easy, rapid, cost-effective clinical test which can be performed by paraclinical health practitioners (physiotherapists) and orthopedic surgeons. PMID:22144749
Divecha, Akshay; Bhaskar, Atul
Introduction The World Health Organization (WHO) claimed osteoarthritis as a civilization-related disease. The effectiveness of preoperative physiotherapy among patients suffering hip osteoarthritis (OA) at the end of their conservative treatment is rarely described in the literature. The aim of this study was to assess the quality of life and musculoskeletal health status of patients who received preoperative physiotherapy before total hip replacement (THR) surgery within a year prior to admission for a scheduled THR and those who did not. Material and methods Forty-five patients, admitted to the Department of Orthopaedics and Traumatology of Locomotor System for elective total hip replacement surgery, were recruited for this study. The assessment consisted of a detailed interview using various questionnaires: the Harris Hip Score (HHS), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), the 36-Item Short Form Health Survey (SF-36), and the Hip disability and Osteoarthritis Outcome Score (HOOS), as well as physical examination. Patients were assigned to groups based on their attendance of preoperative physiotherapy within a year prior to surgery. Results Among patients who received preoperative physiotherapy a significant improvement was found for pain, daily functioning, vitality, psychological health, social life, and (active and passive) internal rotation (p < 0.05). Conclusions Patients are not routinely referred to physiotherapy within a year before total hip replacement surgery. This study confirmed that pre-operative physiotherapy may have a positive influence on selected musculoskeletal system status indicators and quality of life in hip osteoarthritis patients awaiting surgery.
Czyzewska, Anna; Walesiak, Katarzyna; Krawczak, Karolina; Cabaj, Dominika; Gorecki, Andrzej
We discuss the role of imaging techniques in examining the athletes with sports injuries involving the pelvis and the hip. Pelvis and hip pain is of difficult clinical clarification because of the various athletic injuries which may affect the bone or soft tissues at different anatomic sites. Moreover, the symptoms of pelvis and hip injuries are similar in most cases
Fosco De Paulis; Angelo Cacchio; Osvaldo Michelini; Arcadio Damiani; Raoul Saggini
Total hip arthroplasty in the high riding dislocated hip is a technically difficult undertaking, with major reconstruction required on both the acetabular and femoral sides. With reconstruction at a near-anatomic hip center, reduction of the arthroplasty is difficult because of the long-standing limb shortening. The major block to reduction is tension of the soft tissues, particularly the hamstrings. We report
Paul N. Smith; Graham A. Gie
Based upon the life histories of six Indigenous hip hop artists of the Beat Nation artist collective, this essay captures how Indigenous hip hop has the potential to revolutionize environmental education. Hip hop provides Indigenous youth an emancipatory space to raise their opposition to neocolonial controls of Indigenous territories that…
Gorlewski, Julie; Porfilio, Brad J.
The linguistic dimensions of globalized hip-hop cannot be understood simply as a byproduct of English as an American export. As hip-hop mobilizes, it is common (and arguably necessary) for global hip-hop communities to struggle through purposeful, semiotically rooted dialectics over what constitutes "authentic" and respectable forms of local…
The aim of the present work is to analyze the consequences of repetitive extreme hip motion in professional ballet dancers. The motivation for this study is that dancers' activities can be at the origin of hip osteoarthritis. To verify this hypothesis, bone poses of patient-specific hip joint are obtained using an optical motion capture system, while soft tissue artifacts are
Caecilia Charbonnier; Etienne Lyard; Nadia Magnenat-Thalmann
Habitual dislocation of the hip (HDH) in children is a rare entity and can be a causative factor for popping or snapping hip which is a common problem in children with good prognosis. We report a case of HDH in a 9 year old girl who was suffering from frequent snapping hip at night, its course and treatment process. PMID:25250256
Najd Mazhar, Farid; Ghazavi, Mohammad Taghi; Jafari, Davod; Gharanizadeh, Kaveh
Background and purpose Immediate implant stability is a key factor for success in cementless total hip arthroplasty (THA). Low bone mineral density (BMD) and age-related geometric changes of the proximal femur may jeopardize initial stability and osseointegration. We compared migration of hydroxyapatite-coated femoral stems in women with or without low systemic BMD. Patients and methods 61 female patients with hip osteoarthritis were treated with cementless THA with anatomically designed hydroxyapatite-coated femoral stems and ceramic-ceramic bearing surfaces (ABG-II). Of the 39 eligible patients between the ages of 41 and 78 years, 12 had normal systemic BMD and 27 had osteopenia or osteoporosis. According to the Dorr classification, 21 had type A bone and 18 had type B. Translational and rotational migration of the stems was evaluated with radiostereometric analysis (RSA) up to 2 years after surgery. Results Patients with low systemic BMD showed higher subsidence of the femoral stem during the first 3 months after surgery than did those with normal BMD (difference = 0.6, 95% CI: 0.1–1.1; p = 0.03). Low systemic BMD (odds ratio (OR) = 0.1, CI: 0.006–1.0; p = 0.02), low local hip BMD (OR = 0.3, CI: 0.1–0.7; p = 0.005) and ageing (OR = 1.1, CI: 1.0–1.2; p = 0.02) were risk factors for delayed translational stability. Ageing and low canal flare index were risk factors for delayed rotational stabilization (OR = 3, CI: 1.1–9; p = 0.04 and OR = 1.1, CI: 1.0–1.2; p = 0.02, respectively). Harris hip score and WOMAC score were similar in patients with normal systemic BMD and low systemic BMD. Interpretation Low BMD, changes in intraosseous dimensions of the proximal femur, and ageing adversely affected initial stability and delayed osseointegration of cementless stems in women. PMID:22489886
In a fuel assembly having spaced fuel rods, an outer hollow tubular flow channel surrounding the fuel rods so as to direct flow of coolant\\/moderator fluid there-along, and at least one spacer being disposed along the channel and about the fuel rods so as to maintain them in side-by-side spaced relationship, an arrangement for disposing the spacer in a desired
Introduction of spacers in coating steroid antigen or enzyme conjugates or immunogen is known to exert an influence on the sensitivity of steroid enzyme immunoassays. We have introduced hydrophobic and hydrophilic spacers between enzyme and steroid moieties and studied their effects on functional parameters of enzyme immunoassays, using cortisol as a model steroid. Cortisol-3-O-carboxymethyloxime–bovine serum albumin (F-3-O-CMO-BSA) was used as
Seema Nara; Vinay Tripathi; Shail K. Chaube; Kiran Rangari; Harpal Singh; Kiran P. Kariya; Tulsidas G. Shrivastav
This paper, presents a robust spacer technology for definition of deca-nanometer gate length MOSFETs. Conformal deposition, selective anisotropic dry-etching and selective removal of sacrificial layers enabled patterning of an oxide hard mask with deca-nanometer lines combined with structures defined with I-line lithography on a wafer. The spacer gate technology produces negligible topographies on the hard mask and no residual particles
J. Hållstedt; P.-E. Hellström; Z. Zhang; B. G. Malm; J. Edholm; J. Lu; S.-L. Zhang; H. H. Radamson; M. Östling
An increase in the marginal discrepancy is seen after cementation with a luting agent and provision of cement space with a die-spacer is the most preferred method to avoid it. Recommended thickness of die-spacer is 25-40 ?m. Smaller die-spacer thickness was consistently found at the axio-occlusal line angles as compared to the other surfaces which has been postulated to that the spacer paint tends to flow away from the sharp line angles and cusp tips as a result of increased surface tension. The absence of adequate relief spaces in these areas impedes the flow of cement beyond the occlusal portion of the casting, which would result in incomplete seating because of hydraulic pressure. Fifty stone dies were duplicated from a steel die and were divided into five groups of sample size 10, where the die-spacer was selectively placed. Measurements were taken at four points, 90° apart from each other with the help of optical microscope. Later all the castings were cemented using Glass Inomer cement as a luting agent, under a 10 kg static load and measurements were recorded. Statistical analysis showed samples with no spacer had the maximum pre and post cementation gap while the least discrepancy was seen in group with additional layer of die-spacer painted over the axio-occlusal line angle. The results were highly significant which clearly indicated the superiority of this group over others. Within limitations of the study, it can be said that application of additional layer of die-spacer at the axio-occlusal line angle will help in decreasing the post cementation marginal discrepancy in full cast metal crowns. PMID:23997463
Aditya, Priyam; Madhav, V N V; Bhide, S V; Aditya, Amita
In a turbine having closed-circuit steam-cooling passages about the rim of the rotor during steady-state operation, compressor discharge air is supplied to the rotor bore for passage radially outwardly into the wheel space cavities between the wheels and spacers. Communicating slots and channels in the spacers and wheels at circumferentially spaced positions enable egress of the compressor discharge air into
Philip M. Caruso; Sacheverel Quentin Eldrid; Azad A. Ladhani; Alan Richard DeMania; Gene David Palmer; Ian David Wilson; Lisa Shirley Rathbun; Robert Craig Akin
Biofouling was studied in full-scale and pilot-scale installations, test-rigs and membrane fouling monitors by conventional methods as well as Magnetic Resonance Imaging (MRI). Independent of permeate production, the feed spacer channel pressure drop and biomass concentration increased similarly in a nanofiltration pilot installation. In the presence of a feed spacer the absolute feed channel pressure drop increase caused by biomass
J. S. Vrouwenvelder; J. C. Kruithof; M. L. Johns
The sequence of the 18S–25S ribosomal RNA gene intergenic spacer (IGS) of Avena sativa was determined. DNA was cloned after polymerase chain reaction amplification of the IGS. The spacer of 3980 bp is composed of non-repeated sequences and five tandem arrays of repeated sequences, named A to E. Homology between oats IGS and other grass species was found. Tandem arrays
C. Polanco; M. Pérez Vega
Hip arthroscopy is a minimally invasive surgical technique often performed in athletes who want an expeditious return to sport. To the authors' knowledge, no studies in the literature provide a time frame or criteria for return to sport after hip arthroscopy. The purpose of this study was to develop an aggregate recommendation for return to sport after hip arthroscopy based on data assimilated from high-volume hip arthroscopy centers. Twenty-seven orthopedic surgeons from high-volume hip arthroscopy centers completed a survey regarding return to sport after hip arthroscopy. The questionnaire asked surgeons to give a time frame for return to sport and to choose meaningful criteria that an athlete must meet prior to return to sport. Surgeons were asked to categorize various common sports as high, medium, or low risk with regard to the hip. The aggregate results were used to create standardized recommendations for time, criteria, and risk for return to competitive sports. Regarding time frame for return to sport, 70% of surgeons recommended 12 to 20 weeks. In addressing criteria for return to sport, 85% of surgeons recommended that patients need to be able to reproduce all motions involved in their sport without pain. A majority of surgeons recommended criteria of pain-free running, jumping, lateral agility drills, and single-leg squats. Finally, surgeons categorized sports requiring the most movement and impact of the hip joint (football, basketball, wrestling, and martial arts) as high-risk sports. Sports with less impact on the hip, such as golf, were ranked as low risk. PMID:25275978
Domb, Benjamin G; Stake, Christine E; Finch, Nathan A; Cramer, T Luke
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 statistical investigation on the hip prostheses implanted in 70 medical centres. The first aim of this study is a systematic characterization of materials used for hip prostheses, and it has been provided by BEAMnrc Monte Carlo code. The second aim is to evaluate the capabilities of a specific treatment planning system, Pinnacle 3, when dealing with dose calculations in presence of metals, also close to the regions of high-Z gradients. In both cases it has been carried out an accurate comparison versus experimental measurements for two clinical photon beam energies (6 MV and 18 MV) and for two experimental sets-up: metallic cylinders inserted in a water phantom and in a specifically built PMMA slab. Our results show an agreement within 2% between experiments and MC simulations. TPS calculations agree with experiments within 3%.
Palleri, Francesca; Baruffaldi, Fabio; Angelini, Anna Lisa; Ferri, Andrea; Spezi, Emiliano
Mechanical testing of McLaughlin hip nail-plates manufactured from 316 LVM stainless steel was performed. The mode of failure is described and the results are compared with previous tests of McLaughlin implants manufactured from Cobalt-Chromium-Molybdenum alloy. As there was no significant difference between these two products as regards the basic mechanical problem of failure of the nail-plate junction, it is recommended that the design be changed to make the implant suitable for internal fixation of unstable trochanteric fractures. PMID:7446023
Jensen, J S
Summary\\u000a Hip geometry measurements of outer diameter and buckling ratio at the intertrochanter and shaft of the hip dual energy X-ray\\u000a absorptiometry (DXA) scan predicted incident hip fracture in postmenopausal women. These associations, independent of age,\\u000a body size, clinical risk factors, and conventional areal bone mineral density, suggest hip geometry plays a role in fracture\\u000a etiology and may aid in
A. Z. LaCroix; T. J. Beck; J. A. Cauley; C. E. Lewis; T. Bassford; R. Jackson; G. Wu; Z. Chen
During sexual reproduction, Euplotes crassus precisely fragments its micronuclear chromosomes and synthesizes new telomeres onto the resulting DNA ends to generate functional macronuclear minichromosomes. In the micronuclear chromosomes, the macronuclear-destined sequences are typically separated from each other by spacer DNA segments, which are eliminated following chromosome fragmentation. Recently, in vivo chromosome fragmentation intermediates that had not yet undergone telomere addition have been characterized. The ends of both the macronuclear-destined and eliminated spacers were found to consist of six-base, 3? overhangs. As this terminal structure on the macronuclear-destined sequences serves as the substrate for de novo telomere addition, we sought to determine if the spacer DNAs might also undergo telomere addition prior to their elimination. Using a polymerase chain reaction approach, we found that at least some spacer DNAs undergo de novo telomere addition. In contrast to macronuclear-destined sequences, heterogeneity could be observed in the position of telomeric repeat addition. The observation of spacer DNAs with telomeric repeats makes it unlikely that differential telomere addition is responsible for differentiating between retained and eliminated DNA. The heterogeneity in telomere addition sites for spacer DNA also resembles the situation found for telomeric repeat addition to macronuclear-destined sequences in other ciliate species. PMID:11788715
Möllenbeck, Matthias; Klobutcher, Lawrence A.
The objective of this study was to evaluate right proximal femur shape as a risk factor for incident hip fracture using active shape modeling (ASM). A nested case-control study of white women 65 years of age and older enrolled in the Study of Osteoporotic Fractures (SOF) was performed. Subjects (n = 168) were randomly selected from study participants who experienced hip fracture during the follow-up period (mean 8.3 years). Controls (n = 231) had no fracture during follow-up. Subjects with baseline radiographic hip osteoarthritis were excluded. ASM of digitized right hip radiographs generated 10 independent modes of variation in proximal femur shape that together accounted for 95% of the variance in proximal femur shape. The association of ASM modes with incident hip fracture was analyzed by logistic regression. Together, the 10 ASM modes demonstrated good discrimination of incident hip fracture. In models controlling for age and body mass index (BMI), the area under receiver operating characteristic (AUROC) curve for hip shape was 0.813, 95% confidence interval (CI) 0.771–0.854 compared with models containing femoral neck bone mineral density (AUROC = 0.675, 95% CI 0.620–0.730), intertrochanteric bone mineral density (AUROC = 0.645, 95% CI 0.589–0.701), femoral neck length (AUROC = 0.631, 95% CI 0.573–0.690), or femoral neck width (AUROC = 0.633, 95% CI 0.574–0.691). The accuracy of fracture discrimination was improved by combining ASM modes with femoral neck bone mineral density (AUROC = 0.835, 95% CI 0.795–0.875) or with intertrochanteric bone mineral density (AUROC = 0.834, 95% CI 0.794–0.875). Hips with positive standard deviations of ASM mode 4 had the highest risk of incident hip fracture (odds ratio = 2.48, 95% CI 1.68–3.31, p < .001). We conclude that variations in the relative size of the femoral head and neck are important determinants of incident hip fracture. The addition of hip shape to fracture-prediction tools may improve the risk assessment for osteoporotic hip fractures. © 2011 American Society for Bone and Mineral Research. PMID:20878772
Baker-LePain, Julie C; Luker, Kali R; Lynch, John A; Parimi, Neeta; Nevitt, Michael C; Lane, Nancy E
Total hip arthroplasty in the high riding dislocated hip is a technically difficult undertaking, with major reconstruction required on both the acetabular and femoral sides. With reconstruction at a near-anatomic hip center, reduction of the arthroplasty is difficult because of the long-standing limb shortening. The major block to reduction is tension of the soft tissues, particularly the hamstrings. We report a case of ischial tuberosity avulsion fracture following such a complex reconstruction despite femoral shortening subtrochanteric osteotomy. This illustrates the importance of the hamstring group in maintaining the dislocation and emphasizes the need to prevent overtension of the soft tissues in such complex reconstructive procedures. PMID:9726330
Smith, P N; Gie, G A
This case report involves a 56-year-old female (Mrs X) with a traumatic intertrochanteric hip fracture with subtrochanteric extension below a previous Birmingham hip resurfacing. Periprosthetic fractures following hip resurfacing are usually subcapital and treated with a revision or conservative management. We present an unusual surgical problem with an interesting solution stabilising the fracture using a proximal femoral locking compression plate (LCP). Eight months following surgery the patient is able to walk pain free and there is good fixation and stability. PMID:24995142
Macdonald, J.; Robinson, A.; Brown, I.
The clinical incidence of squeaking has been reported with increasing frequency, with ceramic-on-ceramic bearings seemingly most affected. This study investigated potential causes of squeaking in hard-on-hard hip bearings through 2 sets of experimental conditions. Bearing clearance appeared to affect the incidence of squeaking in metal-on-metal surface arthroplasties. The addition of third-body particles to the interface for total hip arthroplasties also affected the incidence of squeaking. In both studies, the incidence of squeaking correlated well with elevated friction. The findings of this study suggest that a likely cause of squeaking in the hip arthroplasty is adverse tribological conditions caused by suboptimal lubrication. There are numerous factors that may cause the suboptimal lubrication, and therefore, it is unlikely that an individual cause for squeaking will be identified. PMID:22480525
Brockett, Claire L; Williams, Sophie; Jin, Zhongmin; Isaac, Graham H; Fisher, John
High-purity aluminum oxide is potentially an attractive implant material for total hip joint replacement, because its biocompatibility, excellent wear resistance, high strength and corrosion resistance. The main problem of alumina is relatively low fracture toughness. Thus, this study is the introduction of ZrO2 as second ceramic phase homogeneously dispersed wihtin an alumina matix. Al2O3\\/ZrO2 nanocomposites disk is prepared by spark
Gang Zhou; Soo Wohn Lee; Yubao Li
Smoking is a prevalent behaviour in the population. The aim of this review is to bring to light the effects of smoking on dental implants. These facts will assist dental professionals when implants are planned in tobacco users. A search of “PubMed” was made with the key words “dental implant,” “nicotine,” “smoking,” “tobacco,” and “osseointegration.” Also, publications on tobacco control by the Government of India were considered. For review, only those articles published from 1988 onward in English language were selected. Smoking has its influence on general as well as oral health of an individual. Tobacco negatively affects the outcome of almost all therapeutic procedures performed in the oral cavity. The failure rate of implant osseointegration is considerably higher among smokers, and maintenance of oral hygiene around the implants and the risk of peri-implantitis are adversely affected by smoking. To increase implant survival in smokers, various protocols have been recommended. Although osseointegrated dental implants have become the state of the art for tooth replacement, they are not without limitations or complications. In this litigious era, it is extremely important that the practitioner clearly understands and is able and willing to convey the spectrum of possible complications and their frequency to the patients. PMID:24478965
Kasat, V.; Ladda, R.
Porous tantalum is an alternative metal for total joint arthroplasty components that offers several unique properties. Its high volumetric porosity (70% to 80%), low modulus of elasticity (3 MPa), and high frictional characteristics make it conducive to biologic fixation. Tantalum has excellent biocompatibility and is safe to use in vivo. The low modulus of elasticity allows for more physiologic load transfer and relative preservation of bone stock. Because of its bioactive nature and ingrowth properties, tantalum is used in primary as well as revision total hip arthroplasty components, with good to excellent early clinical results. In revision arthroplasty, standard and custom augments may serve as a structural bone graft substitute. Formation of a bone-like apatite coating in vivo affords strong fibrous ingrowth properties and allows for substantial soft-tissue attachment, indicating potential for use in cases requiring reattachment of muscles and tendons to a prosthesis. Development of modular components and femoral stems also is being evaluated. The initial clinical data and basic science studies support further investigation of porous tantalum as an alternative to traditional implant materials. PMID:17077337
Levine, Brett; Della Valle, Craig J; Jacobs, Joshua J