Late fatigue fracture of a modern cemented forged cobalt chrome stem for total hip arthroplasty: a report of 10 cases.
Explore the source record for details and available documents.
Arthroplasty, Replacement, Hip↗
Biomedical subjects
Michael T Manley
Publications and source records attributed to Michael T Manley.
The potential for bone loss in acetabular structures following THA.
Attempts to preserve periacetabular bone stock following total hip replacement have largely ignored the potential for stress shielding in the acetabulum. We sought to quantify the change in stress distribution in acetabular bone with components of varying material stiffness by developing a high-resolution 3-D finite element model from CT scans of a young female donor. Periprosthetic bone stresses and strains on the left pelvis were compared with hemispherical cups of various material properties and with a horseshoe shaped polymeric design described in the recent literature. We observed unphysiologic periacetabular bone stress and strain fields for all designs tested. For hemispherical components, reduction of the acetabular shell material modulus caused modest changes in bone stress compared to the changes in implant geometry. The horseshoe shaped cup more effectively loaded the acetabular structures than the hemispherical design. Our results suggest stress and strain fields in pelvic structures after introduction of hemispherical acetabular components predict inevitable bone adaptation that can not be resolved by changes in implant material properties alone. Radical changes in implant design may be necessary for long-term maintenance of supporting structures in the reconstructed acetabulum.
Acetabulum↗
The basis for a second-generation highly cross-linked UHMWPE.
Highly cross-linked ultra-high molecular weight polyethylene (UHMWPE) decreases wear at the hip by more than 50% compared with conventional UHMWPE. However, melted highly cross-linked polyethylene may be susceptible to fatigue cracking, and annealed highly cross-linked polyethylene may be susceptible to in vivo oxidation. The second-generation highly cross-linked UHMWPE (X3 HXPE) uses a sequential irradiation and annealing process. It preserves mechanical strength properties and has the highest survivorship in functional fatigue testing. The free radical content is low, and its performance under accelerated aging is the same as virgin UHMWPE. Hip simulator studies with 32-mm acetabular components demonstrated 97% wear reduction compared with conventional UHMWPE, and 62% compared with a clinically successful first-generation annealed highly cross-linked polyethylene. The crystallinity, density, and tensile strength of the X3 HXPE material was unchanged by oxidative challenge. X3 HXPE material articulating on cobalt-chromium alloy yields a volumetric wear rate very similar to that of metal-on-metal articulations, but eliminates the concerns of metal ion release. Wear particles generated from the X3 HXPE were the same size as those produced from conventional UHMWPE. Preliminary results suggest X3 HXPE can be used for cups larger than 36 mm.
Equipment Failure Analysis↗
Hydroxyapatite-coated femoral components: 15-year minimum followup.
Hydroxyapatite-coated femoral components were introduced to enhance fixation, but concerns were raised about whether the coating would be maintained over time. We therefore determined the long-term clinical and radiographic results of a proximally hydroxyapatite-coated femoral component and compared the mechanical failure rate to other fixation methods at similar lengths of followup. The study group, culled from a large, multicenter prospective study population, consisted of 146 patients (166 hips) with followup of 15 to 18 years. Average age at time of the index procedure was 51 years, and the most common diagnoses were osteoarthritis (71%) and osteonecrosis (11%). Average Harris hip scores were 42.7 preoperatively and 91.5 at most recent followup. Radiographically, one stem showed stable fibrous fixation, and all other unrevised stems were bony stable. Of 13 stem revisions in the study population, only one stem has been revised for aseptic loosening. Forty-nine percent of hips have an osteolytic lesion in proximal areas of Gruen Zones 1, 7, 8, or 14 only. Both the femoral aseptic revision and mechanical failure rates are 0.6% at 15-year minimum followup. The data demonstrate excellent long-term survivorship of this hydroxyapatite-coated femoral component used in a relatively young patient group.
Adolescent↗
Metal-on-Metal total hip replacement: what does the literature say?
Second-generation metal-on-metal (M/M) total hip replacements were introduced into clinical use in the late 1980s and demonstrate equivalent survivorship to conventional metal-on-polyethylene prostheses. Wear rates are comparable to those of first-generation designs that survived for a long time in the body. Biological effects from metal ions remain a concern. Patients with both first- and second-generation M/M hips have higher levels of cobalt and chromium in their blood and urine than either patients with metal-on-polyethylene devices or unoperated patients. Concerns include the potential for acquired hypersensitivity, mutagenicity, and carcinogenicity. However, reports of proven adverse effects are scant. Prospective, randomized trials with follow-up in excess of 15 years will be needed to differentiate between the performance and effects of M/M and other bearing combinations. Key words: totalhip arthroplasty, metal-on-metal, wear, biological effects, clinical results.
Allergens↗
An in vitro model for fluid pressurization of screw holes in metal-backed total joint components.
Fluid pressure may stimulate osteolysis near screw holes in joint arthroplasty components. We developed a generalized in vitro model of a polyethylene liner and metal backing with a screw hole to investigate whether implant design factors influence local fluid pressure. We observed an order of magnitude of variation in the peak screw hole pressure (from 16.0 and 163 kPa) under clinically relevant loading conditions. Of the implant factors investigated, the surface finish of the metallic base plate had the greatest effect on peak screw hole fluid pressures; the thickness of the polyethylene liner, as well as the gap between the liner and the base plate, were also significant design variables. Our data suggest that unpolished metal base plates, thick polyethylene liners, and tight conformity between the liner and the metal base plate will all contribute to significantly reduced peak screw hole fluid pressures in joint arthroplasty.
Bone Screws↗
Five-year experience with Crossfire highly cross-linked polyethylene.
UNLABELLED: Our purpose was to compare the clinical wear performance of highly cross-linked (Crossfire) polyethylene with conventional (N2Vac) polyethylene total hip bearings. We implanted 56 hips (47 patients) with Crossfire acetabular bearing liners and compared their wear performance with 53 conventional polyethylene inserts. Wear and clinical data were collected retrospectively at a minimum 4-year and average 5-year followup. The linear femoral head penetration rate measured from plain radiographs was 0.055 mm/year +/- 0.022 mm/year for the Crossfire polyethylene and 0.138 mm/year +/- 0.073 mm/year for the control, a reduction of 60% for the Crossfire components. Calculated annual wear was 0.036 mm/year for the Crossfire components and 0.131 mm/year for the controls, a reduction of 72%. Radiographic review at most recent followup showed a reduction in erosive osteolytic lesions of the proximal femur for the Crossfire components compared with controls, also suggesting a reduction in debris release for the Crossfire components. Complications leading to revision were not seen in the Crossfire or control groups. These clinical findings suggest that this particular highly cross-linked polyethylene can provide wear reduction and an alternate bearing surface for active patient populations. LEVEL OF EVIDENCE: Therapeutic study, Level III (retrospective comparative study). See the Guidelines for Authors for a complete description of levels of evidence.
Aged↗
Arc-deposited hydroxyapatite-coated cups: results at four to seven years.
UNLABELLED: A second-generation arc-deposited hydroxyapatite-coated acetabular component was developed after detailed analysis of a failed first-generation grit-blasted hydroxyapatite-coated cup. In our prospective multicenter study we aimed to compare clinical results and survivorship of the newly designed cup to the previous cup and to a similarly designed porous-coated cup during the same time period. The effect of bearing surface-alumina-on-alumina to polyethylene-on-metal-was analyzed. Consecutive patients were assigned randomly to one of three groups: arc-deposited hydroxyapatite-coated cup with alumina-on-alumina bearing surface; porous-coated cup with alumina-on-alumina bearing surface; or porous-coated cup with polyethylene-on-metal bearing surface. A fourth comparison group with a grit-blasted hydroxyapatite-coated cup and polyethylene-on-metal bearing surface was culled from a previous study. Acetabular mechanical failure rate is 0.0%, 0.0%, 1.9%, and 11.2% for the arc-deposited hydroxyapatite-coated, porous-coated with alumina bearing surface, porous-coated with polyethylene-on-metal bearing, and grit-blasted hydroxyapatite-coated cup, respectively, at 4- to 7-years' followup. There are no cases of acetabular osteolysis or femoral neck scalloping and no radiolucent lines in any zone with the arc-deposited hydroxyapatite-coated cup. The cups with the alumina-on-alumina bearing surface had less scalloping of the femoral neck than those with a polyethylene-on-metal bearing surface. Early results with this second-generation arc-deposited hydroxyapatite-coated cup are promising. LEVEL OF EVIDENCE: Therapeutic study, Level I (high-quality randomized trial with statistically significant difference or no statistically significant difference but narrow confidence intervals). See the Guidelines for Authors for a complete description of levels of evidence.
Adult↗
A titanium-encased alumina ceramic bearing for total hip arthroplasty: 3- to 5-year results.
UNLABELLED: We examined whether encasing the alumina ceramic total hip arthroplasty insert in a thin titanium sleeve would reduce significantly or eliminate insert chipping on impaction of the insert into the shell. We also compared results, including observations of osteolysis, of the Trident study group with those of the predecessor alumina bearing couple design to determine clinical improvement and radiographic stability. Beginning in October 1996, 328 alumina ceramic bearings were implanted by six surgeons in 316 patients as a part of a prospective, randomized United States Investigational Device Exemption three-arm study comparing an alumina ceramic bearing with a control bearing of cobalt-chromium on polyethylene. In September 1999, a fourth arm of the study (Trident) was added. The Trident insert was recessed within a thin titanium sleeve. At three to five years followup, osteolysis was found in 0% of the patients with the Trident insert and in 0.5% of the patients with an alumina bearing couple. At a mean followup of 4.2 years (range, 3-5 years) no ceramic chips, fractures, or ceramic bearing failures have occurred. Encasing the alumina ceramic insert in a titanium sleeve seems to have resolved the issue of insert chipping on impaction and supports the continued use of Trident bearings in relatively young patients. LEVEL OF EVIDENCE: Therapeutic study, Level II-1 (prospective comparative study-patients treated one way compared with a group of patients treated in another way at the same institution). See the Guidelines for Authors for a complete description of levels of evidence.
Aluminum Oxide↗
Alternative bearing surfaces: alumina ceramic bearings for total hip arthroplasty.
Osteolysis resulting from polyethylene wear debris is one of the most common causes of implant failure in young, active individuals who undergo total hip arthroplasty. Reducing wear may help extend the life of the implant in these patients. Contemporary alumina ceramic/alumina ceramic bearing articulations are harder, scratch resistant, and more hydrophilic than other bearing couples, resulting in reduced wear and reduction of particle load to the surrounding tissue. Therefore, bearings made of alumina ceramic may be a preferable bearing choice for younger, more active patients. To investigate this hypothesis, 495 patients (514 hips), average age 53 years, were enrolled in a prospective, randomized, multicenter study comparing an alumina-on-alumina ceramic bearing to a cobalt-chromium-on-polyethylene bearing control. At an average of 4 years after implantation, no difference in clinical outcome was observed between groups. There were no fractures of the ceramic head or liner, nor were there any revisions caused by the ceramic liner. Another investigational group was added to the study 1 year after enrollment in the original study was closed. The same inclusion/exclusion criteria were used. A total of 194 consecutive patients (209 hips) received an alumina liner that included a thin metal backing designed to allow bearing replacement and ease surgical assembly. At an averagefollow-up of 30 months, no liner or head chips or fractures were observed in this group.
Aluminum Oxide↗
Hydroxyapatite-coated prostheses in total hip and knee arthroplasty.
Hydroxyapatite-coated implants have demonstrated extensive bone apposition in animal models. The osseous interface develops even in the presence of gaps of 1 mm and relative motion of up to 500 mum. Development of implant-bone interfacial strength is due to the biological effects of released calcium and phosphate ions, although surface roughness leads to increased interface strength in the absence of interface gaps. The clinical results at fifteen years after total hip replacements have demonstrated that hydroxyapatite-coated femoral stems perform as well as, and possibly better than, other types of cementless devices, with the added benefit of providing a seal against wear debris. Hydroxyapatite-coated acetabular components must have a mechanical interlock with bone in order to take advantage of the coating effects. Clinical analyses of these types of designs at seven years have indicated good survivorship. The performance of a hydroxyapatite-coated implant depends on coating properties (thickness, porosity, hydroxyapatite content, and crystallinity), implant roughness, and overall design. The most reliable predictor of the performance of a device is success in long-term clinical studies.
Acetabulum↗
"The lysis threshold": an erroneous and perhaps misleading concept? By Harris WH.
Explore the source record for details and available documents.
Arthroplasty, Replacement, Hip↗
A 10-year minimum follow-up of hydroxyapatite-coated threaded cups: clinical, radiographic and survivorship analyses with comparison to the literature.
We evaluated the clinical, radiographic, and survivorship outcomes in a series of 418 threaded hydroxyapatite-coated acetabular cups (Arc2f; Osteonics, Allendale, NJ) implanted in a consecutive series of 384 patients undergoing primary total hip arthroplasty. In all cases, the cup was screwed into the prepared acetabulum. Bone screws were used to provide secondary fixation. At a minimum 10-year follow-up, 304 cups were available for analysis. The cumulative survivorship (mechanical failure as endpoint) at that time was 99.43% +/- 0.0104. Two hundred seventy-six hips were available for full clinical and radiographic review at or after the tenth anniversary. No unstable implants were noted; all implant fixation interfaces were classified as "stable bone ingrown," and the cup migration rate was zero. Based on the survivorship achieved with this implant, our results compare favorably with survivorship reported for the best cemented and cementless acetabular implant designs.
Acetabulum↗
Ten-year results with hydroxyapatite-coated total hip femoral components in patients less than fifty years old. A concise follow-up of a previous report.
We report the results of total hip arthroplasty with use of a proximally hydroxyapatite-coated femoral component after a minimum follow-up of ten years in a group of patients who were less than fifty years old at the time of the primary procedure. In the five years since the original publication of our study, two additional stems have undergone revision. Thus, a total of six stems have been revised. A small amount of erosive scalloping of the proximal part of the femur was seen in nearly one-half of the hips; however, all unrevised stems were radiographically stable and no hip had intramedullary osteolysis. The revision rate because of aseptic loosening of the stem was 0.9%, which compares favorably with that for other stems and other fixation methods in young patients at this point in time. This stem is currently being paired with a highly cross-linked polyethylene liner because of cup failures and the need for reoperation secondary to excessive polyethylene wear and proximal femoral osteolysis.
Adolescent↗
A literature review of the association between wear rate and osteolysis in total hip arthroplasty.
The establishment of a polyethylene wear rate threshold for the development of osteolysis at the hip would allow surgeons to identify patients at risk for osteolysis and to implement selective, more frequent follow-up. We reviewed publications that met certain criteria for wear and osteolysis measurement. Based on this review, the incidence of osteolysis increases as the rate of wear increases. The literature indicates that osteolysis rarely is observed at a wear rate of <0.1 mm/y. We suggest that a practical wear rate threshold of 0.05 mm/y would eliminate osteolysis. This wear threshold suggests that the new cross-linked polyethylenes would reduce osteolysis, provided that in vivo wear rates mirror those observed in vitro. To facilitate future comparison of published data, we suggest that longitudinal wear studies adopt consistent edge detection-based wear measurement techniques and uniform osteolytic lesion classification and measurement schema.
Arthroplasty, Replacement, Hip↗
Hydroxyapatite coated stems in younger and older patients with hip arthritis.
A primary aim of research in total hip arthroplasty is to extend longevity through improved fixation and decreased wear and osteolysis. Age range of patients receiving hip implants is ever increasing as technology improves and average life span increases. The current report focuses on minimum 10-year results of a proximally hydroxyapatite-coated stem in patients with degenerative joint disease, comparing those 45 years and older (n = 229 hips) with younger patients (n = 41 hips). Clinically, the average Harris hip score is 91 points and 88 points in the older and younger groups, respectively. Mechanical failure rates for the stem are 0.4% and 2.4%, with one stem revision for aseptic loosening and no radiographically loose stems in each age group. Proximal femoral osteolysis is seen more often in younger patients (48% versus 38%), and younger patients (six hip arthroplasties) had reoperation for wear or osteolysis. Therefore, this stem has performed well at a 10-year minimum followup. However, polyethylene wear and osteolysis have led the authors to begin a United States Food and Drug Administration study of an alumina ceramic-on-alumina ceramic bearing surface in conjunction with the same stem. At 2 years minimum followup, there have been no complications related to the ceramic bearing surfaces, no cortical erosions, and no stem revisions for aseptic loosening.
Age Factors↗
Osteolysis: a disease of access to fixation interfaces.
Long-term clinical studies of total hip replacement suggest a direct relationship between bearing wear and periprosthetic osteolysis, particularly if polyethylene wear is greater than a threshold value of 0.1 mm per year. The current clinical trend to cross-linked polyethylene and hard-to-hard bearings attempts to ensure that bearing wear remains below this threshold. Fluid pressure generated in the hip during patient activity also has been implicated in the formation of periprosthetic lesions. Pressure fluctuation measured during manipulation of the hip at revision, or the identification of modular components that pump fluid during loading, suggest cyclic pressure may be a causative factor in bone resorption. Animal studies show the adverse effect of direct pressure on osteocytes. At more than 10 years followup, the low incidence of osteolytic lesions in retrospective reviews of successful cemented and cementless implant designs suggest that osteolysis is not an inevitable consequence of particle or pressure generation in the hip. If the quality of implant fixation prohibits fluid access to the surrounding bone, the rate of osteolysis is minimal. It is evident that whether the active factor in osteolysis is pressure, wear particles, or both, adverse periprosthetic effects can be minimized if access to the fixation interfaces in the hip is denied.
Adolescent↗