In primary and revision total hip arthroplasty (THA), the acetabular component continues to pose greater challenges than the femoral component. Numerous factors lead to polyethylene wear, which subsequently affects primary THA survival. Progressive polyethylene wear is associated with the occurrence of osteolysis, especially overlying ...

The impact of femoral head surface roughness on wear of gamma-irradiation sterilized (3 MRad in nitrogen, crosslinked) and nonsterilized (not crosslinked) UHMWPE acetabular cups has been evaluated. Gravimetric wear testing was performed in a hip joint simulator for 2 x 10(6) cycles. CoCrMo heads were used with ...

INTRODUCTION: Revision surgery in patients showing polyethylene wear and acetabular osteolysis without visible acetabular cup loosening involves the difficult decision of whether to revise only the liner or both the cup and the liner. The purpose of this study is to compare the outcomes of ...

Orthopaedic surgeons must currently choose from several types of ultra high molecular weight polyethylene acetabular cups that differ in their material properties and in the methods used for their sterilization. Information on the wear resistance of these different cups may help in the selection process. This study ...

BackgroundContact pressure of UHMWPE acetabular cup has been shown to correlate with wear in total hip replacement (THR). The aim of the present study was to test the hypotheses that the cup geometry, abduction angle, thickness and clearance can modify the stresses in cemented polyethylene ...

BackgroundIt has been indicated that, in the long term, the rate of wear and the degree of osteolysis observed with uncemented acetabular components are greater than those associated with cemented cups, but most studies which compare the wear characteristics of cementless with cemented cups ...

A major concern during revision hip arthroplasty is acetabular bone loss and bleeding during the extraction of well-fixed cementless acetabular cup, because no interface exists between the host bone and the cup. Forceful removal of such component using curved gouges and osteotomes often leads to extended bone loss ...

We reviewed 81 consecutive ABG I primary total hip replacements implanted in 72 patients between January 1993 and December 1998. The mean follow-up was 8.2 (range 7-12) years. There was significant polyethylene wear and osteolysis associated with the acetabular cup . The cumulative survival of the cup with revision ...

A radiographic study of a singular type of threaded cup, revised due to aseptic loosening, was performed with Einzel-Bild-Roentgen-Analyse (EBRA) to detect eventual risk factors and patterns of loosening. Fifty-three cups of 50 patients were revised. Forty-two cups could be measured with EBRA. No cup had obvious ...

Eighty-six polyethylene liners and 56 metallic shells of acetabular components were evaluated by visual and stereomicroscopic examination for impingement, backside polyethylene wear, creep, and fretting at the screw-metallic shell interface using a subjective scoring system. Medical records and radiological data were available in 65 and 46 patients, ...

This study analyzed the wear patterns of, and wear volume formulae for, cylindrically elongated acetabular cup liners. The geometric patterns of the wear surface were first classified, then wear volume formulae were derived by integral calculus. SolidWorks((R)) software or ...

The major failure mode of cemented or noncemented acetabular fixation is osteolysis produced by biologic reaction to polyethylene and metallic debris. A monoblock acetabular noncemented component offers advantages in reducing the failure mechanism of acetabular cups. First, there is no extra-articular back surface ...

The purpose of the study was to investigate the contact stresses in 3 different acetabular cup rim designs (new, worn, chamfer) during edge loading, after microseparation of ceramic on ceramic hip prostheses. A 3-dimensional finite element analysis was conducted for a 28-mm diameter alumina ceramic bearing with a radial clearance of 40 ?m using a normal ...

Ultra-high molecular weight polyethylene acetabular cups backed by Ti-6Al-4V acetabular shells were articulated against Co-Cr-Mo alloy, ion-implanted Co-Cr-Mo alloy, and zirconia ceramic femoral heads in a hip joint simulator. Three tests of three million walking cycles each were run with five different head-cup ...

We report a case of a 46-year-old male patient who sustained a fracture of the Burch�Schneider anti-protrusio cage (APC) that was implanted 13 years before. The fracture occurred in the transitional area to the proximal flange and was caused by direct and recurrent contact between the prosthetic metal head and the acetabular device. Late failure was related to increased ...

Two methods were developed and evaluated for cross-linking the bearing surface of a polyethylene acetabular cup to a limited depth, in order to improve its resistance to wear without degrading the mechanical properties of the bulk of the component. In the first method, low-energy electron beams were used to cross-link only the bearing ...

We applied a Raman confocal spectroscopic technique to quantitatively assess the structural features of two kinds of acetabular cups made of ultra-high molecular weight polyethylene. We wanted to know whether polyethylene cups belonging to different generations, and thus manufactured by different procedures, possess different molecular ...

Alumina ceramic-on-ceramic total hip arthroplasty (THA) has been widely used due to its advantages such as low wear, scratch resistance, wettable surface and relatively low biological reactivity of the wear particles. Nevertheless, this material in THA still persists to be one of the major concerns about the risk of fracture, due to its brittleness. Many ...

Joint simulators are important tools in wear studies of prosthetic joint materials. The type of motion in a joint simulator is crucial with respect to the wear produced. It is widely accepted that only multidirectional motion yields realistic wear for polyethylene acetabular cups. ...

A realistic pin-on-disk wear test method for prosthetic joint materials has been developed. The new method, called circularly translating pin-on-disk (CTPOD), yields wear rates and wear mechanisms similar to those observed in retrieved polyethylene acetabular cups. In the established methods, ...

The total penetration of femoral heads into acetabular cups is achieved by a combination of long-term wear and early non-recoverable deformation or creep. The former is important in determining the total rate of production of polyethylene wear debris, recently implicated in the development of osteolysis and ...

BackgroundLoosening of acetabular components often leads to bony defects. Management of extensive acetabular bone loss in hip revision arthroplasty can be a tremendous challenge.Questions/purposesWe asked whether a reconstruction with impacted bone grafts will provide a durable and pain-free function in extensive acetabular defects. We ...

5 ultra-high molecular weight polyethylene acetabular cups articulated against alumina femoral heads for 35 million walking cycles in a hip joint simulator designed for wear tests of total hip prostheses. The specimens were from Protek, Biomet, Link, Howmedica and Thackray. In the Howmedica specimen, the wear was ...

The anatomic femoral component and Harris-Galante porous II (HGPII) cup were developed to provide more reliable bone ingrowth. We performed 20 cementless total hip arthroplasties (THAs) with anatomic stem/HGPII cup with 22-mm head in 14 consecutive patients, and evaluated the clinical and radiological results for a mean follow-up of 12.8�years. The ...

Ultra-high-molecular weight polyethylene (UHMWPE) wear, debris-induced osteolysis is a frequent cause of failure of total hip arthroplasty. Metal-on-metal total hip arthroplasty eliminates the generation of UHMWPE particulate debris. Although the volumetric wear of a metal-on-metal articulation may be lower than a metal-UHMWPE articulation, the number of ...

One concern about the fixation of HA-coated implants is the possible disintegration of the surface, with the migration of HA granules into the joint space, producing third-body wear. We report a study of six revisions of HA-coated polyethylene RM cups at 9 to 14 years after successful primary arthroplasty. In all six hips, we found HA granules embedded in ...

New material combinations have been introduced as the bearing surfaces of hip prostheses in an attempt to prolong their life by overcoming the problems of failure due to wear-particle-induced osteolysis. This will hopefully reduce the need for revision surgery. The study detailed here used a hip simulator to assess the volumetric wear rates of ...

This paper presents a computational simulator for the hip to compute the wear and heat generation on artificial joints. The friction produced on artificial hip joints originates wear rates that can lead to failure of the implant. Furthermore, the frictional heating can increase the wear. The developed computational model calculates the ...

Small-diameter cemented Metasul� cups have been previously identified to be at high risk of early loosening. We asked whether this particular mode of failure was associated with a specific histological feature. Periprosthetic tissues were obtained at the time of revision of two aseptically loose cemented Metasul� cups. Each tissue sample was processed ...

Ultra-high molecular weight polyethylene acetabular cups of 5 different total hip systems (M�ller, 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 M�ller and Charnley-Elite, ion-implanted Ti-6Al-4V in Mallory-Head, ...

The wear of acetabular cups made from conventional gamma-sterilized, and electron-beam cross-linked ultra-high-molecular-weight polyethylene was studied with a biaxial hip wear simulator. The femoral heads were either polished or roughened so that they represented the type of roughening and the value of surface ...

Ultra-high molecular-weight polyethylene (UHMWPE) has been used in total joint replacement for the last three decades. Despite the recent advancements in prosthesis design, the wear of UHMWPE remains a serious clinical problem; the release of wear debris may induce osteolysis and implant loosening. Controlling the quality of the polyethylene is essential ...

IntroductionMany kind of hydroxyapatite-coated cups were used, with favorable results in short term studies; it was supposed that its use could improve osteointegration of the cup, enhancing thus stability and survivorship. The purpose of this study is to analyze the long term behavior of the hemispheric HA coated, Dual Radius Osteonics ...

The wear of hip-joints is a significant clinical problem, which causes adverse tissue reactions leading to bone absorption and consequent loosening of the fixation. Artificial hip joints retrieved after use and tested on simulators typically exhibit a 'stripe' wear area on the surface of the alumina bearing components. Focused Ion Beam (FIB) microscopy has ...

This is a prospective review of 135�HA-coated ABG I total hip arthroplasty (THA) systems with a mean clinical and radiographic follow-up of 8.5�years. The 5-year survival rate was 85%, but 22% of the patients were dissatisfied. Revision THA was already indicated in 28% of the patients, with 26% indicated for cup loosening. PE wear was detected by x-ray ...

BackgroundThe low wear rates of crosslinked polyethylenes provide the potential to use larger diameters to resist dislocation. However, this requires the use of thinner liners in the acetabular component, with concern that higher contact stresses will increase wear, offsetting the benefits of the crosslinking.Questions/purposesWe asked ...

There is currently much discussion over the use of ceramic femoral components against metal acetabular cups, for use in total hip arthroplasty. The current study investigates six hot isostatically pressed alumina femoral heads of 38 mm diameter articulating against six as-cast Co-Cr-Mo metallic acetabular cups. ...

Total joint replacements (TJRs) have a limited lifetime, but the introduction of components that exhibit good lubricating properties with low friction and low wear could extend the life of TJRs. A novel acetabular cup design using polyurethane (PU) as a compliant layer (to mimic the natural joint) has been developed. This study ...

Metallosis is usually defined as aseptic fibrosis, local necrosis, or loosening of a device secondary to metallic corrosion and release of wear debris. It is an occasional but characteristic clinical finding in patients who have a metal-on-metal design of total hip replacement, or when metal surfaces contact after a failure or erosion of the polyethylene component. We report ...

OBJECTIVES:Our primary aim was to compare the long?term survivorship rates and the rates of successful osseointegration between two different types of uncemented acetabular components.INTRODUCTION:Two types of alloys have primarily been used for the manufacture of the uncemented acetabular components: titanium?based and cobalt?based alloys. A ...

A new uncemented acetabular component, the Cambridge cup, has been designed to mimic the anatomy and physiology of subchondral bone in order to minimise stress shielding and enhance long-term component stability. Cambridge cups were implanted in a cohort of 50 women who presented with displaced sub-capital fracture of the femoral neck. ...

A review of current clinically applied biomaterials for the femoral heads and acetabular cups of total hip prostheses (UHMWPE, CoCrMo alloys, alumina and zirkonium) in terms of their resistance to wear is presented. Further developments in metallic and ceramic materials over the last few years have now left UHMWPE as the weakest link ...

Wear of the socket liner and resulting osteolysis are the major causes of failure in cementless hip arthroplasties. We report alarming wear of the first-generation polyethylene liner of the cementless porous-coated Biomet Universal cup. Radiographs of 107 primary hip arthroplasties were analyzed retrospectively. The mean follow-up time ...

In�vitro studies demonstrating excessive wear in polyethylene cups sterilized using gamma irradiation and stored in air led to the abandonment of this sterilization technique. We evaluated the clinical wear performance of a metal femoral component on a polyethylene cup in a hip prosthesis from a selected subset ...

Alumina hip replacement prostheses have been analyzed following in vitro simulated microseparation. The worn surfaces of the alumina acetabular cup and femoral head were investigated using scanning electron microscopy (SEM) and atomic force microscopy (AFM) which identified four different wear zones. Focused ion beam (FIB) ...

While favorable tribological properties and allowance for larger femoral head sizes have made metal-on-metal (MoM) bearings an increasingly popular choice for total hip arthroplasty, concerns have mounted regarding adverse reactions to metal wear debris and ions. MoM cups differ from conventional polyethylene cups in terms of edge ...

A dual-mobility acetabular component consists of a large, fixed, porous-coated acetabular component and a bipolar femoral component. These components are often called tripolar components. This configuration provides a stable, well-fixed implant platform against bone and 2 articular interfaces, a large polyethylene surface directly apposed to a highly ...

Total hip replacement (THR) is one of the most successful elective operations currently being performed. However, increased implant wear in the femoral head-acetabulum articulation has been found to limit the long-term survivorship of the procedure. Clinical complications of this wear process include mechanical failure of the polyethylene insert as well as ...

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

Studies of explanted hip prostheses have shown high wear rates of ultra-high molecular weight polyethylene (UHMWPE) acetabular cups and roughening of the surface of the metallic femoral head. Bone and bone cement particles have also been found in the articulating surfaces of some joints. It has been proposed that bone or bone cement ...

The effects of ion implantation of nitrogen on the corrosive-wear behavior of the surgical alloy, Ti-6Al-4V (6 wt.% Al, 4 wt.% V), were investigated. Tests made use of an apparatus designed to produce conditions similar to those that obtain at the sliding interface between the alloy head of the femoral component and the ultrahigh molecular weight polyethylene (UHMWPE) ...

Polyethylene wear after total hip arthroplasty may occur as a result of normal gait and as a result of subluxation and relocation with impact. Relocation of a subluxed hip may impart a moment to the cup creating sliding as well as compression at the cup liner interface. The purpose of the current study is to quantify, by a validated ...

Alumina ceramic heads have been previously shown to reduce polyethylene wear in comparison to cobalt chrome (CoCr) heads in artificial hip joints. However, there are concerns about the brittle nature of ceramics. It is therefore of interest to investigate ceramic-like coatings on metallic heads. The aim of this study was to compare the friction and wear of ...

A 24-year-old patient with a history of juvenile rheumatoid arthritis underwent a primary cementless left total hip arthroplasty (THA). The original THA consisted of an Optifix 54 cup with a 3-mm thick polyethylene liner, an Optifix size 4 stem (Smith & Nephew Richards, Memphis, Tennessee) and a Biolox aluminum 32-mm femoral head. Fourteen years later, radiographs ...

Press-fit implantation may result in acetabular component deformation between the ischial-ilial columns ("pinching"). The biomechanical and clinical consequences of liner pinching due to press-fit implantation have not been well studied. We compared the effects of pinching on the polyethylene fracture risk, potential wear rate, and stresses for two ...

The study uses idealized two-dimensional finite element models to examine the behaviour of the acetabular construct following revision hip arthroplasty, carried out using the Slooff-Ling impaction grafting technique. The behaviour of bone graft was considered in detail, with non-linear elasticity and non-associated plasticity being adopted. Load was applied to the ...

A swab cup construction includes a molded resilient plastic reinforcing cage with fingers spaced circumferentially about the cup and deformable with the cup so as to engage the well pipe and reinforce the cup. The fingers have flexing characteristics compatible with the rubber cup and are ...

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

In an earlier paper, the authors presented a new method of computation of slide tracks in the relative motion between femoral head and acetabular cup of total hip prostheses. For the first time, computed tracks were verified experimentally and with an alternative method of computation. Besides being an efficient way to illustrate hip kinematics, the shapes ...

Wear of the polyethylene in total joint prostheses has been a source of morbidity and early device failure, which has been extensively reported in the last 20 years. Although research continues to attempt to reduce the wear of polyethylene joint-bearing surfaces by modifications in polymer processing, there is a renewed interest in the use of ...

The aim of the work has been the development of a hip joint simulator for comparative wear rate studies of long duration. A five-station apparatus has been designed, constructed and tested. Five total hip joints can be tested at the same time in identical conditions. The flexion-extension motion and the superior-inferior component of the joint contact force are incorporated. ...

Wear of ultrahigh-molecular-weight polyethylene and the subsequent lytic response to the particulate wear debris are the dominant problems in total joint arthroplasty surgery. Wear testing apparatus can play a vital role in the in vitro evaluation of the many factors involved in wear, such as head size, surface ...

Serial radiographic measurements of polyethylene wear were performed in 38 hips (33 patients) with primary cementless total hip arthroplasty (THA). The average follow-up period was 131.8 months. All prostheses were assessed as radiographically stable at the latest follow-up. A two-dimensional method was used to calculate the relative migration of the femoral head center to the ...

Wear behaviour of TiN(titanium nitride)-coated Ti and Ti-6AI-4V alloy against UHMW polyethylene was studied in hip simulation test. Ti alloys possess an excellent combination of mechanical properties and biocompatibility, however, they suffer from inadequate wear resistance. Thus, their use as articulating components of total joint replacements requires ...

Fourteen patients were followed by roentgen stereophotogrammetry for 3 years after hip arthroplasty. In 11 of the 14 acetabular components, definite wear was identified. The mean wear rate was 0.13 mm per year. There was no correlation between the wear and loosening of either the acetabular or ...

Founded in Barcelona in 1985, the Spanish Hip Society (SECCA) now has over 200 members and organizes annual meetings. Papers read in the SECCA meeting are published in Hip International, since our society is affiliated with this journal. The late Sixties and early Seventies coincided with the beginning and development of total hip replacement. At present, over 30,000 hip prostheses are implanted ...

In the present work, based on high frequency wavelet analysis of dynamic signals of mechanical systems, a multiple-resolution wavelet analysis is carried out, to the signal obtained from an accelerometer mounted on the structure of a hip prosthesis wearing test device. The prostheses employed had a femoral head made of aluminum oxide and the acetabular ...

BackgroundWe 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 ...

In the area of orthopaedic implants, particularly total hip joint replacements, a metal-plastic combination is still the most popular choice consisting of a femoral head fabricated from 316L stainless steel, Ti alloy or Co-Cr alloy in contact with an ultra-high molecular weight polyethylene (UHMWPD) acetabular cup. It is recently considered that ...

Ceramic-on-ceramic and metal-on-metal bearing surfaces are often employed for total hip replacement because of their resistance to wear. However, they have some limits: brittleness is a major concern for ceramic, and ion release is a drawback for metal. To reduce the effect of these limitations, a hybrid coupling of ceramic-on-metal has been proposed. The theoretical advantage ...

A three-axial, single-station hip joint simulator was designed and built for wear and friction studies on total hip prostheses. The design of the apparatus is described in detail. Continuous level walking is simulated. All three motion components, flexion-extension, abduction-adduction and internal-external rotation, are included. The motions are implemented ...

The combination of materials that still has highest wear resistance for total hip replacement is ceramic-on-ceramic. However, brittleness is a major concern for ceramics: in vivo and in vitro studies on ceramic hip prostheses correlate microseparation with hip noise, ceramic wear, or ceramic liner damage. Ceramic microseparation can lead to edge load, ...

BackgroundWe performed a retrospective study to evaluate the results of acetabular circumferential medial wall osteotomy, a procedure designed to provide secure fixation of a cementless hemispherical acetabular cup for the sequelae of septic arthritis of the hip.MethodsWe assessed 38 total hip arthroplasties (THAs) with circumferential ...

Hip joint replacement is described as the greatest achievement in orthopaedic surgery in the twentieth century. The field has been dominated for some forty years by implants based upon metallic femoral heads and stems and polymeric acetabular cups. At the dawn of the new Millennium, many alternative materials and designs are now being proposed or ...

Modern ceramic bearings used in total hip arthroplasty (THA) consist of a femoral head (ball) articulating inside a hemispherical acetabular cup (socket); the ball and socket are made of alumina (Al(2)O(3)) and Al(2)O(3)-based composite materials. In the present study, total hip bearings were made from a different ceramic material, silicon nitride ...

It is well known that the wear factor for ultra-high molecular weight polyethylene (UHMWPE) sliding on metallic or ceramic counterfaces is largely independent of contact stress for modest loading conditions and sliding distances. However, it is now recognized that under more severe stress levels and with sliding distances comparable to those encountered in current replacement ...

Aseptic loosening from polyethylene wear debris is the leading cause of failure for metal-on-polyethylene total hip implants. Third-body debris ingress to the bearing space results in femoral head roughening and acceleration of polyethylene wear. How third-body particles manage to enter the bearing space between the closely conforming articulating surfaces ...

Aseptic loosening from polyethylene wear debris is the leading cause of failure for metal-on-polyethylene total hip implants. Third body debris ingress to the bearing space results in femoral head roughening and acceleration of polyethylene wear. How third body particles manage to enter the bearing space between the closely conforming articulating surfaces ...

Appropriate anatomic concepts for surgery to treat femoroacetabular impingement require a precise appreciation of the native acetabular anatomy. We therefore determined (1) the spatial acetabular rim profile, (2) the topography of the articular lunate surface, and (3) the 3-D relationships of the acetabular opening plane comparing 66 ...

A new innovative low-wear bearing for use in total hip arthroplasty, a wear couple consisting of carbon fiber-reinforced poly-ether-ether-ketone (CF-PEEK), has been shown to be highly biocompatible and to have excellent tribological performance in the laboratory. We report the results of our technical and histologic analysis of a CF-PEEK composite ...

Ensuring the stability of a cemented PROSTALAC cup (Depuy, Warsaw, Ind) in the presence of severe superior acetabular segmental deficiency is critical to the success of the first-stage surgery. We present an illustrative case and the surgical technique required to achieve this. PMID:21752577

Five fresh cadaver pelves were cleaned of soft tissue and instrumented with strain gauges. The acetabula were reamed, and a cementless cup, oversized at the periphery, was inserted. The applied force and cup acceleration were measured during insertion and used to calculate an effective mass of the cup, insertion device, and pelvis ...

Artificial hip joints have an average lifetime of 10 years due to aseptic loosening of the femoral stem attributed to polymeric wear debris; however, there is a steadily increasing demand from younger osteoarthritis patients aged between 15 and 40 year for a longer lasting joint of 25 years or more. Compliant layers incorporated into the acetabular ...

Ten acetabular cups coated with hydroxyapatite (HA) had originally been inserted in five primary and five revision total hip replacements. The thickness of the HA was 155 +/- 35 microm. The cups, which were well-fixed, were retrieved, with their adherent tissue, at reoperation after 0.3 to 5.8 years because of infection (five hips), ...

While total hip replacement represents the major success story in orthopaedic surgery in the twentieth century, there is much interest in extending even further, early in the twenty first century, the life of implants. Osteolysis has been identified as a major factor limiting the life of prostheses, with indications that fine polyethylene wear debris, generated primarily at ...

This randomized study was performed to compare wear and migration of five different cemented total hip joint articulations in 150 patients. The patients received either a Charnley femoral stem with a 22.2?mm head or a Spectron EF femoral stem with a 28?mm head. The Charnley articulated with a ?-sterilized Charnley Ogee acetabular cup. ...

An elastohydrodynamic lubrication model developed for a ball-in-socket configuration in a previous studies by the present authors (Jalali-Vahid et al., Thinning films and tribological interfaces, 26th Leeds-Lyon Symposium on Tribology, 2000, pp. 329-339) was applied to analyse the lubrication problem of a typical artificial hip joint replacement, consisting of an ultra-high molecular weight ...

The purpose of this study was to compare acetabular component positioning using an imageless system to a matched control group using conventional techniques. Thirty procedures were performed using navigation. A multislice computed tomographic scan was used to assess cup position. There was no significant difference between mean inclination (P = .11) and ...

The survival of acetabular components depends on several factors: wear, osteolysis and septic or aseptic loosening. Osteolysis seems to be the main cause for concern in cementless arthroplasties. Acetabular osteolysis results from particle debris and segmental unloading of acetabular bone by rigid sockets. We ...

Osteolysis due to particulate wear debris associated with ultrahigh molecular weight polyethylene (UHMWPE) components of total joint replacement prostheses has been a major factor determining their in vivo lifetime. In recent years, radiation crosslinking has been employed to decrease wear rates in PE components, especially in ...

Osteolysis due to particulate wear debris associated with ultrahigh molecular weight polyethylene (UHMWPE) components of total joint replacement prostheses has been a major factor determining their in vivo lifetime. In recent years, radiation crosslinking has been employed to decrease wear rates in PE components, especially in ...

Metal-on-metal hip arthroplasties undergo distinct release of toxic metal particles and ions. Thus, it is necessary to minimize this. In order to evaluate the wear behaviour of metal-on-metal hip replacements it is essential to understand the micro-structural changes in the sub-surface region. Previous studies revealed that cobalt chromium metal-on-metal implants are able to ...

The predominant cause of late-state failure of total hip replacements is wear-mediated osteolysis caused by wear particles that originate from the ultrahigh molecular weight polyethylene (UHMWPE) acetabular cup surface. One strategy for reducing wear particle formation from UHMWPE is to modify ...

Wear particle-induced osteolysis is a major cause of aseptic loosening in THA. Increasing wear resistance of polyethylene (PE) occurs by increasing the cross-link density and early reports document low wear rates with such implants. To confirm longer-term reductions in wear we compared cross-linked polyethylene ...

... wear rate of prosthesis contact surfaces is greatly accelerated if loose fragments of bone cement become detached and act as an abrasive in the ...

The metal-on-metal bearing total hip prosthesis is expected to reduce the risk of debris-related osteolysis. However, several reports demonstrated that the socket-stem impingement in the metal-on-metal prosthesis due to the implant malposition results in titanium wear debris and secondary metallosis. In this article, we presented a case of massive metallosis due to ...

The purpose of this paper was to evaluate the results of acetabular revisions with the use of an oblong revision cup that is designed with its longitudinal diameter elongated relative to its transverse diameter. Between 1996 and 2001, 62 hips in 60 patients underwent an acetabular revision with the insertion of a LOR ...

Nanoindentation has been used to compare the micromechanical properties of direct molded vs. machined bearing surfaces on UHMWPE tibial components. Differences in micromechanical properties (hardness and elastic storage modulus) were observed between these two types of bearing surfaces, and are believed to result from (1) differences in surface roughness, and (2) differences in morphology of the ...

The wear on the stem cones of retrieved Exeter Universal hip stems has been assessed using scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX) and surface profilometry. The in-service life of these prosthetic stems varied, up to a maximum of 7 years. A combination of SEM, EDX and visual assessment indicates that the stem cones have not suffered from any ...

Contact mechanics analysis for a typical McKee-Farrar metal-on-metal hip implant was carried out in this study. The finite element method was used to predict the contact area and the contact pressure distribution at the bearing surfaces. The study investigated the effects of the cement and underlying bone, the geometrical parameters such as the radial clearance between the ...

Introduction of highly crosslinked polyethylene has increased interest in large femoral heads, because thin acetabular liners can be used while maintaining low wear rates and larger heads decrease the incidence of instability. However, crosslinking and subsequent thermal treatments can cause decreased mechanical properties that might obviate the reduced ...

Fifty-three patients (54 hips) treated with cemented total hip reconstruction with the aid of an acetabular mesh made of Vitallium (Howmedica Inc., Rutherford, New Jersey), a cobalt-chrome molybdenum alloy, to reinforce the medial cement for deficient bone stock in the central acetabular region, were evaluated at an average follow-up period of 6.8 years ...

PURPOSE. To evaluate long-term outcomes of total hip arthroplasty (THA) using the Perfecta cementless system. METHODS. 73 men and 76 women aged 65 to 88 (mean, 71) years underwent 168 THAs using the Perfecta cementless system and were followed up for a mean of 13 (10 to 15) years. 19 patients had bilateral THA. The diagnoses were idiopathic osteoarthritis (n=121), osteonecrosis of the femoral head ...

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 ...

Counterface damage in the form of scratches, caused by bone cement, bone or metallic particles, has been cited as a cause of increased wear of ultra-high molecular weight polyethylene (UHMWPE) acetabular cups. It is known that high levels of particulate wear debris lead to osteolysis. Surface damage was ...

Followed by successful demonstration of high interfacial tensile strength in a new design of cemented all-polyethylene acetabular cup, interfacial shear strength was investigated in this study, with the use of canine-size prototypes of polymethylmethacrylate (PMMA) precoated UHMWPE acetabular cups. In addition to ...

Cementless acetabular components are routinely used in revision hip surgery. Nevertheless, few investigators have assessed their retention and efficacy over the long term. This occurs mainly in cases which originate from moderate to severe bone losses (cavitary and or segmental) requiring the use of morselized and or bulk bone graft. Our objective in the present study is to ...

This paper explores the effect of under-reaming on micromotion at the cup/bone interface of a press-fit acetabular cup. A cadaver experiment was performed on 11 acetabuli implanted with a cementless acetabular cup. The loading profile simulated hip impingement at the extremes of motion and ...

A finite element model has been developed to predict in vivo micro motion between a modular acetabular cup and liner after cement less total hip arthroplasty. The purpose of this study is to experimentally validate the model. Six LVDT sensors were used to monitor the micromotion of the liner when subjected to loading conditions ranging from 250 N to 5000 ...

The theoretical advantage of using thinner acetabular components in hip resurfacing has not yet been clinically verified. Our purpose was to test the hypothesis of bone conservation and assess the effects of using a thinner acetabular component on hip biomechanics and clinical outcome. We compared the bone conservation, biomechanical results, and ...

The authors propose a simple and practical method to measure radiologically the angle of ante- or retroversion of the acetabular cup using a goniometer. It only necessitates an anteroposterior radiograph centered on the femoral head and another one centered on the public symphysis. Special x ray equipment, compass, conversion table, mathematical formulas, ...

The acid resistance of tantalum coated and uncoated human hip joint prostheses was studied with commercial CrCoMo acetabular cups. The samples were exposed to 10% HCl solution and the quantities of dissolved Cr, Co, and Mo were measured with proton-induced X-ray emission (PIXE). The absolute quantities were obtained with the use of Cr and Se solution ...

Hydrated polymer coatings on polymer substrates are common for many biomedical applications, such as tissue engineering constructs, contact lenses, and catheters. The thickness of the coatings can affect the mechanical behavior of the systems and the cellular response, but measuring the coating thickness can be quite challenging using conventional methods. We propose a new method, that is, ...

BackgroundMeasuring the orientation of acetabular cup after total hip arthroplasty is important for prognosis. The verification of these measurement methods will be easier and more feasible if we can synthesize prosthesis radiographs in each simulated condition. One reported method used an expensive mechanical device with an indeterminable precision. We ...

Studies of explanted femoral heads have shown that scratches caused by bone cement, bone or metallic particles are present on the rubbing surface. This damage has been cited as a cause of increased wear of ultra-high molecular weight polyethylene (UHMWPE) acetabular cups and it is known that the particulate wear ...

Hip resurfacing is femoral bone preserving, but there is controversy regarding the amount of bone removed at the acetabular side. We therefore compared the implanted acetabular cup sizes in primary THAs between two resurfacing devices and a conventional press-fit cup using a series of 2134 THAs ...

Bioengineering reasons for increased wear and failure of metal-on-metal (MoM) bearings in hip prostheses have been described. Low wear occurs in MoM hips when the centre of the femoral head is concentric with the centre of the acetabular component and the implants are correctly positioned. Translational or rotational malpositioning of ...

AbstractTotal hip arthroplasty (THA) in young patients has a high loosening rate, due in part to acetabular deformities that may compromise bone fixation and polyethylene wear. We therefore asked whether wear or osteolysis and loosening differ in patients under 40�years of age with alumina-on-alumina THA compared to those who are ...

Different bearing surfaces, including alumina-on-alumina, have been used to avoid osteolysis.We prospectively followed 288 patients (319 hips) in which an alumina-on-alumina cup was used with a hydroxyapatite stem. The patients� mean age was 52.7 (range, 14�70�years), and the minimum followup was 3�years (mean, 4.7�years; range, 3�8�years). At final followup, ...

We report the results of 24 acetabular reconstructions in which cemented polyethylene cups and tamped corticocancellous allografts were used for severe acetabular bone deficiency. Eleven hips had type-II (cavitary) bone deficiency and 13 had type-III (combined) defects. At a mean follow-up of 5.8 years, two components had migrated more ...

Complementary clinical and laboratory studies were performed to identify variables associated with polyethylene wear following total hip replacement, and to elucidate the mechanisms responsible for accelerated wear in the total hip arthroplasty construct.Observational cohort studies were performed using a prospective clinical database of more than 4000 ...

In view of the controversy about bulk autografts to provide support for the acetabular cup in reconstruction of the dysplastic hip, a series of 15 dysplastic hips were investigated as follows: Femoral head autograft shelf reconstruction and cemented acetabular components were evaluated at an average follow-up period of 99 months after ...

The use of large metal on metal bearings has led to a reduction in the risk of dislocation post hip arthroplasty. Because of this, and also because of the technical difficulties associated with resurfacing surgery in particular, it could be argued that a less meticulous approach to acetabular cup placement has developed in comparison with conventional ...

The ideal acetabular component is characterised by reliable, long-term fixation with physiological loading of bone and a low rate of wear. Trabecular metal is a porous construct of tantalum which promotes bony ingrowth, has a modulus of elasticity similar to that of cancellous bone, and should be an excellent material for fixation. Between 2004 and 2006, ...

This article summarises a clinical and radiographical analysis of 30 acetabular revisions in patients younger than 55�years old, performed with impaction bone grafting and cemented cups. Preoperative Merle D�Aubigne and Postel functional score was an average 7 points. At a mean follow-up of 86.5�months (range 34�228) functional score averaged 16.3 ...

Polyetheretherketone (PEEK) is one of the up-to-date organic polymer thermoplastics with applications in orthopaedics and trauma medicine. This study presents a detailed analysis of its tests and applications in clinical medicine. A wide range of PEEK modifications and composites are commercially available, e.g., PEEK-Classix, PEEK-Optima, Endolign and Motis. They differ in their physical ...

High wear rates and high patient ion levels have been associated with high (>�55�) cup inclination angles for metal-on-metal surface replacements. Wear rates and patterns have been simulated for ceramic-on-ceramic bearings by applying microseparation to replicate head offset deficiency. We tested 39-mm metal-on-metal surface ...

wear de- bris which may accelerate loosening of implant bone interfaces. The position of im- pingement systems used in orthopaedics is the need for fiducial pins to be surgically implanted into bone before preDevelopment and Validation of a Navigational Guidance System for Acetabular Implant Placement* 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 ...

Wear debris related osteolysis is recognised as being the main cause of failure in joint replacements based on UHMWPE inserts. However, many solutions and �new� polyethylenes have been suggested in order to address this issue. This review discusses �historical� issues associated with UHMWPE, such as oxidation, sterilization method and storage, as well as �new� ...

Wear debris related osteolysis is recognised as being the main cause of failure in joint replacements based on UHMWPE inserts. However, many solutions and "new" polyethylenes have been suggested in order to address this issue. This review discusses "historical" issues associated with UHMWPE, such as oxidation, sterilization method and storage, as well as "new" topics, such as ...

ABSTRACT: BACKGROUND: Correct placement of the acetabular cup is a crucial step in total hip replacement to achieve a satisfactory result and remains a challenge with free hand techniques. Imageless navigation may provide a viable alternative to freehand technique and improve placement significantly. The purpose of this project was to assess and validate ...

BackgroundCorrect placement of the acetabular cup is a crucial step in total hip replacement to achieve a satisfactory result and remains a challenge with free-hand techniques. Imageless navigation may provide a viable alternative to free-hand technique and improve placement significantly. The purpose of this project was to assess and validate ...

Massive acetabular bone loss (more than 50% of the acetabular area) can result in insufficient native bone for stable fixation and long-term bone ingrowth of conventional porous cups. The development of trabecular metal cages with osteoconductive properties may allow a more biological and versatile approach that will help restore bone ...

A subject-specific three-dimensional finite element (FE) pelvic bone model has been developed and applied to the study of bone-cement interfacial response in cemented acetabular replacements. The pelvic bone model was developed from CT scan images of a cadaveric pelvis and validated against the experiment data obtained from the same specimen at a simulated single-legged ...

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 ...

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 ...

BACKGROUND: The recent interest in hip resurfacing arthroplasty is motivated by its potential advantages over THA. One advantage of hip resurfacing arthroplasty is that it conserves bone on the femoral side; however, it is unclear whether it does so on the acetabular side. QUESTIONS/PURPOSES: We determined whether the amount of acetabular reaming and ...

A series of pelvic and acetabular injuries caused by horse riding accidents is reported. The importance of wearing appropriate protective clothing when riding is emphasised. ImagesFigure 1Figure 2Figure 3Figure 4

Computed tomography usually can provide accurate documentation of the adequacy of a reduction in congenital dislocation of the hip. It should supplement other radiographic examinations when the status of a reduction is in question because the patient is wearing a plaster cast. The computed tomography scan provides a clear image of the reduction in the transverse plane, so that ...

Implantation of a cementless press-fit acetabular cup during hip arthroplasty alters stress transfer to the periacetabular bone, resulting in stress shielding of cancellous bone and enhanced load transfer to cortical bone. Theoretically, the thicker, stiffer and larger acetabular cup of a hip resurfacing may ...

The purpose of the present study was to evaluate the 6- to 11-year follow-up results of hemispherical porous-coated cups implanted into dysplastic hips using press-fit technique without screws focusing on the amount of host bone coverage. There were 87 patients who underwent 98 primary total hip arthroplasties. Bony coverage was measured as the angle between the vertical line ...

BackgroundHydroxyapatite (HA) is the main inorganic component of bone, and HA coating is widely used on acetabular cups in hip arthroplasty. It has been suggested that this surface finish improves cup survival.MethodsAll patients registered in the Swedish Hip Arthroplasty Register between 1992 and 2007 with an uncemented ...

Twist compression test (TCT) Cup drawing / ironing tests Strip drawing / strip ironing tests fracture � Flange draw-in length � Flange perimeter Deep drawing test Ironing Test Cup Drawing and Ironing and polished to Ra =0.1m) Test Results of Cup Drawing 18 Shorter perimeter Better lubricant Test Results of Cup

Five patients presented with fiber metal mesh shedding of a Harris Galante II acetabular cup detected between 11 and 15 years after implantation. All patients presented with hip pain and 4 demonstrated gross acetabular loosening and fiber metal separation on preoperative radiographs. The remaining patient underwent revision surgery ...

The success of metal bearings is dependent on several parameters. The effects of in vivo forces on the deformation of monoblock acetabular components have yet to be determined. The purpose of our study was to assess the amount of deformation with press-fit fixation of 1-piece metal acetabular components. Four manufacturers provided 1-piece metal ...

We present an update of the clinical and radiological results of 62 consecutive acetabular revisions using impacted morsellised cancellous bone grafts and a cemented acetabular component in 58 patients, at a mean follow-up of 22.2 years (20 to 25). The Kaplan-Meier survivorship for the acetabular component with revision for any reason ...

Wear debris has evolved as the primary etiology of mechanical loosening of cemented as well as uncemented total hip arthroplasty. Osteolysis results from particle formation, and this has been most commonly reported to be secondary to polyethylene wear debris. This article demonstrates that metallic particle debris will also result in significant ...

IntroductionRevision acetabulum arthroplasty is one of the common procedures, which has been on the rise recently. Many implants are available in the market with variable results. Aseptic loosening is the most common indication for revision acetabulum arthroplasty. Birmingham dysplasia cup has been used occasionally in these complex procedures. We know that these implants have ...

The present study aimed to investigate individual and combined influences of the cup inclination and wear on the contact mechanics and fixation of a Charnley hip replacement using finite element method. The effects of cup inclination and penetration on the contact mechanics of articulating bearings as well as the stress within the ...

Five different porous-coated acetabular prosthetic configurations underwent in vitro testing to assess mechanical stability in embalmed cadaver hemipelves: Harris Galante II cup with three cancellous screws, Biomet Universal cup, Whiteside cup with peripheral pegs, Whiteside cup with two ...

Acetabular osteolysis associated with socket loosening is one of the main long-term complications of total hip arthroplasty. In case of major bone loss, where <50% host bone coverage can be obtained with a porous-coated cementless cup, it is generally agreed that a metal ring or cage in association with a cemented component and allograft bone should be ...

BackgroundCotyloplasty is a technique that involves making a perforation of the medial wall of a shallow acetabulum and then inserting an acetabular cup with the medial aspect of its dome beyond the Kohler line. The purpose of this study was to evaluate the results of cementless total hip arthroplasty (THA) using cotyloplasty with focusing on the amount of ...

Taguchi technique is a powerful method of solving engineering problems in order to improve the performance of a process and to enhance the productivity. The methodology for the design of the experiment is proposed in order to find the best parameters for better experimental results with less number of experiments as possible. In this study, Taguchi technique was applied to optimize the compression ...

A custom-made hip is essential for the initial stability and longevity which correspond to an optimal stress distribution, since a standard hip cannot always satisfy every patient's need. In order to find out the designing principles of a custom-made hip, a patient's personal features on which the design was based were acquired. In this study, an integrated finite element model of the hip ...

Aluminia-on-aluminia hip prosthesis with titanium alloy stem was used in 255 cases, for 143 patients with cemented acetabular cup and 112 with an uncemented screw cup. The average age of the patients was 62 years. Of the patients, 35 were treated bilaterally. The indication for surgery was osteoarthritis in 186 cases, fractures and ...

Most noncemented total hip replacements combine a titanium alloy stem, a CoCrMo femoral head and an ultra-high molecular weight polyethylene (UHMWPE) acetabular cup. In spite of its nickel content of up to 1% and the resulting biocompatibility issues in some clinical situations, the higher cost and some difficulties in machining, CoCrMo alloy is preferred ...

... comprised of ultra high molecular weight polyethylene (UHMWPE) were statistically evaluated for wear, degradation, chemical stress, brittleness ...

Carbon nanotubes are highly versatile materials; new applications using them are continuously being developed. Special attention is being dedicated to the possible use of multiwalled carbon nanotubes in biomaterials contacting with bone. However, carbon nanotubes are also controversial in regards to effects exerted on living organisms. Carbon nanotubes can be used to improve the tribological ...

Between March 1990 and May 1991 we performed 85 primary total hip replacements in 74 patients using the Landos Atoll hydroxyapatite (HA)-coated cup and the Corail HA-coated stem. The patients were followed up for a mean of ten years. Of the 85 cups, 26 (31%) have already been revised and a further six are radiologically unstable and awaiting revision. Two ...

Impaction grafting is controversial in the presence of segmental and cavitary acetabular defects and requires the use of supplemental devices to close segmental defects. This approach, however, would allow treating combined deficiencies that could not be managed with impacted cancellous bone alone. We raised the following two questions: (1) What is the survival rate in ...

The Articular Surface Replacement (ASR) hip resurfacing arthroplasty has a failure rate of 12.0% at five years, compared with 4.3% for the Birmingham Hip Resurfacing (BHR). We analysed 66 ASR and 64 BHR explanted metal-on-metal hip replacements with the aim of understanding their mechanisms of failure. We measured the linear wear rates of the acetabular ...

Metal press-fit cups and shells are widely used in hip resurfacing and total hip replacement procedures. These acetabular components are inserted into a reamed acetabula cavity by either impacting their inner polar surface (shells) or outer rim (cups). Two-dimensional explicit dynamics axisymmetric finite element models were developed ...

The purpose of this study was to evaluate the minimum five-year prospective results from the multicentre use of a porous tantalum monoblock acetabular component for primary total hip arthroplasty (THA). A multicentre study was performed in 253 consecutive primary THAs in three separate surgical centres. All patients underwent identical postoperative protocols including ...

Squeaking in total hip arthroplasty (THA) has been observed only in hard-on-hard bearings, such as ceramic-on-ceramic or metal-on-metal. We report the case of a patient with a squeaking THA who had undergone multiple femoral head revisions combined with a composite ceramic cup (polyurethane, ceramic). Squeaking started 6 years postoperatively and ...

Hydroxyapatite (HA) particles have long been suspected to disintegrate from implant surfaces, become entrapped in joint spaces of orthopaedic bearing couples, and start a cascade leading to progressive polyethylene (PE) wear, increased osteolysis, and aseptic loosening. We compared cup revision at 15 years' followup in a randomized group of patients with ...

Using computed tomography-assisted (CT) osteodensitometry, we studied the bone changes that occurred in 12 patients at 2 weeks and again at 1 year after total hip arthroplasty with insertion of a press-fit acetabular cup and an uncemented femoral tapered stem. There was a greater decrease in full bone density (BD) lateral to the femoral stem when compared ...

BACKGROUND: First-generation modular titanium fiber-metal-coated acetabular components had high rates of wear, pelvic osteolysis, and liner dissociation. Second-generation components were designed to reduce the incidence of these problems but it is unclear whether the changes achieved these goals. QUESTIONS/PURPOSES: We asked the following questions: (1) ...

In the 1970s, high failure rates of cemented acetabular components, especially in young patients, in the middle- and long-term prompted a search for alternatives. The Mecring was one of the most popular first generation uncemented, threaded cups widely used in the 1980s for arthroplasty of the hip. First generation threaded cups ...

Factors that influence the outcome of acetabular replacement are design materials, means of fixation, operative technique, and patient-related parameters (e.g., etiology of osteoarthrosis). Whereas improved cementing techniques have produced a marked reduction in the rate of femoral component loosening, the incidence of acetabular loosening has been only ...

BACKGROUND: The recommended range of anteversion of the components in total hip arthroplasty (THA) is between 10 and 30�, but the intraoperative estimation of these versions may be inadequate. HYPOTHESIS: The components anteversion in primary cementless THA using straight stem and hemispherical cup is not significantly different from the native anteversion of the hip joint. ...

Recent in vitro work has shown that sealing the acetabular notch with bone graft in bovine acetabulum samples results in improved cement penetration in the acetabular bone during total hip arthroplasty. Successful sealing of the notch may be identified on postoperative films by a lack of cement extrusion. This study aimed to assess the clinical ...

Quantifying soft-tissue tension around the hip joint during total hip arthroplasty remains difficult. In this study, a three-dimensional computer-aided design model was developed to clarify how component position in total hip arthroplasty contributes to the primary cause of posterior dislocation in cases of flexion, adduction and internal rotation. To better understand the influences of ...

Porous surfaces are intended to enhance osteointegration of cementless implants. Tantalum has been introduced in an effort to enhance osseointegration potential of uncemented components. We therefore compared the clinical outcome of acetabular components with two different porous surfaces. We retrospectively reviewed 283 patients (295 hips) who underwent cementless revision ...

With certain concerns recently reported on metal-on-metal bearing couples in total hip arthroplasty, this study's objective is to review the current knowledge concerning release of metal ions and its potential consequences. Each metal-on-metal implant presents different tribological properties. The analytical techniques for metals are accurate and the Co ion rates seem acceptable up to 2 ?g/L. A ...

Due to their excellent tribology, ceramics are increasingly used for total hip arthroplasty (THA) in young patients. Fracture rates for contemporary ceramics range from 0% to 0.004%. Recently, ceramic liners are encased in a titanium sleeve to further decrease the chances of fracture. We encountered 1 case of a metal-encased acetabular liner fracture in a ceramic-on-ceramic ...

The implantation of an endoprosthetic socket into the acetabulum alters the mechanical stresses in the periacetabular region in a significant manner compared with the natural hip joint. In this way, a remodelling process is initiated. Primary stability to achieve osseointegration and a loading of the acetabulum owing to the biomechanical interaction between cup and bone that ...

Retrieval analyses of alumina-alumina THA components are conducted in order to investigate in vivo wear of implants and provide guidance to material and design improvements. The contribution of the present study consists of the examination, by digital recording of spherical profiles and scanning electron microscopy, of four matched pairs of ceramic THA implants retrieved after ...

BACKGROUND: Alumina-on-alumina bearings have been accepted as a valuable alternative for young and active patients. Alumina fractures, and socket loosening were the main complications reported. But, with the increasing number of prostheses implanted, noise occurrence appeared as a new concern. The primary aim of the present study was to quantify the prevalence of noticing noise in a population ...

After total hip replacement (THR) impingement of the implant components causes shear stresses at the acetabular implant-bone interface. In the current study the finite element method (FEM) was applied to analyse the shear stresses at a fully bonded implant-bone interface assuming total ingrowth of the cup. The FE model of a press-fit ...

The aim of the study was to analyze early results of total uncemented hip replacement with use of small diameter acetabular components. In the group of 13 patients (15 hips) with severe dysplastic coxarthrosis mean age at surgery was 43.6 years. There were 8 right and 7 left hips operated. For clinical assessment Merle d'Aubign� and Postel classification modified by Charnley ...

Intrapelvic acetabular cup migration is a rare but serious complication, which can occur after cup loosening following total hip arthroplasty. To make safe intrapelvic implant removal, several principles must be respected: identification of potential risks with a thorough preoperative workup, preoperative planing of a surgical strategy ...

High-porosity "cancellous metal" coatings have been introduced to increase the fixation and biologic incorporation of acetabular cups. The strength of initial fixation provided by a cancellous metal cups vs conventional alternatives in the deficient revision acetabulum was investigated. Cancellous, plasma-sprayed, and beaded ...

Wear of metal-on-metal bearings causes elevated levels of cobalt and chromium in blood and body fluids. Metal-on-metal bearings have two distinct wear phases. In the early phase, the wear rate is high. Later, it decreases and the bearing enters a steady-state phase. It is expected that as the wear rates decline, ...

We examined the hypothesis that the circumferential osseous apposition around HA-coated implants forms a protective barrier against articular wear debris. Sixty-five hydroxyapatite-coated total hip arthroplasties in 57 patients (age <50years) with polyethylene-metal articulation were evaluated regarding PE-wear, osteolysis, and clinical outcome at a ...