Zirconia Ceramic Heads Research Articles

The Absence of Hydroxyapatite Coating on Cementless Acetabular Components Does Not Affect Long-Term Survivorship in Total Hip Arthroplasty

BackgroundHydroxyapatite (HA) has been applied to joint prostheses as a bioactive coating to prolong their durability. However, HA benefits for cup survival in total hip arthroplasty (THA) remain controversial. In this study, we compared the survival of cups with and without HA coating during a minimum follow-up of 18 years. MethodsIn total, 183 THA cases in 163 patients were analyzed, including 73 cups with HA coating (HA+ group) and 110 without HA coating (HA− group); otherwise, the cups had identical titanium-sprayed rough surfaces and were fixed with screws. In both groups, the same conventional polyethylene liners were applied. Zirconia and alumina ceramic heads were used in the HA+ and HA− groups, respectively. We retrospectively analyzed cup survival based on cup revision for any reason or aseptic loosening as end points. ResultsIn total, 7 and 8 revisions were performed in the HA− and HA+ groups with survival rates of 86.3% and 90.1%, respectively. Among them, 3 cups in the HA− group and 1 cup in the HA+ group were revised for aseptic loosening in 20 years (survival rates 94.1% and 98.7%, respectively). No significant difference was detected in cup survival rates between the groups based on both end points. There were no stem revisions during the observation period. ConclusionThe results suggested that HA coating did not have either beneficial or adverse effects on the long-term cup survival in primary cementless THA.

Evaluation of Two Total Hip Bearing Materials for Resistance to Wear Using a Hip Simulator

Electron beam crosslinked ultra high molecular weight polyethylene (UHMWPE) 32 mm cups with cobalt alloy femoral heads were compared with gamma-irradiation sterilized 26 mm cups and zirconia ceramic heads in a hip wear simulator. The testing was performed for a total of ten million cycles with frequent stops for cleaning and measurement of mass losses due to wear. The results showed that the ceramic on UHMWPE bearing design exhibited higher early wear than the metal on highly crosslinked samples. Once a steady state wear rate was reached, the wear rates of the two types of hip bearing systems were similar with the ceramic on UHMPWE samples continuing to show a slightly higher rate of wear than the highly crosslinked samples. The wear rates of each of the tested systems appear to be consistent with the expectations for low rates of wear in improved hip replacement systems.

Massive Pseudotumor in a 28mm Ceramic-Polyethylene Revision THA: A Case Report

This report reviews the findings of a massive pseudotumor detected pre-operatively in a 13-year-old revision total hip arthroplasty. The case is unique in that the bearing involved was a 28mm zirconia ceramic head on a polyethylene liner. We propose that the pseudotumor arose from ultrafine titanium particles liberated from the proximal porous coating of the femoral stem. We suspect that the osteolysis produced from polyethylene wear exposed the proximal porous coating and, via a process of mechanical abrasion with the surrounding soft tissues, liberated ultrafine titanium particles. We believe the pseudotumor formed because the patient was pre-sensitized to metal debris based upon a pre-operative lymphocyte T-cell proliferation test (LTT). Based upon this unique case, we feel that pseudotumors more likely form when there is a high rate of ultrafine metal particles generated in a pre-sensitized patient. Finally, we introduce what we believe are the main biologic wear responses in THA. Further research is needed to validate this proposed model.Keywords: pseudotumor, ceramic, polyethylene, osteolysis, THA, bearing wear eesponse, titanium debrisLevel of Evidence: AAOS Therapeutic Study Level IV

A Prospective Randomised Study of Periprosthetic Femoral Bone Remodeling Using Four Different Bearings in Hybrid Total Hip Arthroplasty

We performed a study to assess whether different bearing materials have an impact on femoral bone remodeling within the first four years after a hybrid total hip arthroplasty. 205 of 300 patients were available for 4 years follow-up after being randomly allocated to four prosthetic combinations: A: Zirconia ceramic head, polyethylene cup; B: Cobalt-Chrome-Molybdenum head and cup; C: Zirconia ceramic head, polyethylene moulded on the Titanium shell of the Asian cup; D: Alumina head and cup. Bone mineral density (BMD) was measured with Dual-Energy X-ray Absorptiometry in seven Gruen zones adjacent to the femoral implant. Scans were performed within one week after surgery and four years postoperatively. Clinical outcomes were monitored using the Oxford Hip Score (OHS). A high proportion of patients from group D were excluded due to re-operations (19 patients). BMD decreased significantly in all Gruen zones with the largest declines in group D. BMD changes in Gruen zones 1, 2, 3, 6, and 7 correlated with height, and body weight. Advanced age was associated with an increase in bone loss in Gruen zones 1, 2, 3, 6, and 7. A large stem size was associated with a decline in BMD in Gruen zones 1, 6, and 7.Bone remodeling after total hip arthroplasty may depend on the composition of bearing materials, but age, height, weight, and stem size are also related to changes in BMD.

Tribological and material analyses of retrieved alumina and zirconia ceramic heads correlated with polyethylene wear after total hip replacement

It has been suggested that the wear of ultra-high molecular weight polyethylene (UHMWPE) in total hip replacement is substantially reduced when the femoral head is ceramic rather than metal. However, studies of alumina and zirconia ceramic femoral heads on the penetration of an UHMWPE liner in vivo have given conflicting results. The purpose of this study was to examine the surface characteristics of 30 alumina and 24 zirconia ceramic femoral heads and to identify any phase transformation in the zirconia heads. We also studied the penetration rate of alumina and zirconia heads into contemporary UHMWPE liners. The alumina heads had been implanted for a mean of 11.3 years (8.1 to 16.2) and zirconia heads for a mean of 9.8 years (7.5 to 15). The mean surface roughness values of the explanted alumina heads (Ra 40.12 nm and Rpm 578.34 nm) were similar to those for the explanted zirconia heads (Ra 36.21 nm and Rpm 607.34 nm). The mean value of the monoclinic phase of two control zirconia heads was 1% (0.8% to 1.5%) and 1.2% (0.9% to 1.3%), respectively. The mean value of the monoclinic phase of 24 explanted zirconia heads was 7.3% (1% to 26%). In the alumina group, the mean linear penetration rate of the UMWPE liner was 0.10 mm/yr (0.09 to 0.12) in hips with low Ra and Rpm values (13.22 nm and 85.91 nm, respectively). The mean linear penetration rate of the UHMWPE liner was 0.13 mm/yr (0.07 to 0.23) in hips with high Ra and Rpm values (198.72 nm and 1329 nm, respectively). This difference was significant (p = 0.041). In the zirconia head group, the mean linear penetration rate of the UHMWPE liner was 0.09 mm/yr (0.07 to 0.14) in hips with low Ra and Rpm values (12.78 nm and 92.99 nm, respectively). The mean linear penetration rate of the UHMWPE liner was 0.12 mm/yr (0.08 to 0.22) in hips with high Ra and Rpm values (199.21 nm and 1381 nm, respectively). This difference was significant (p = 0.039). The explanted zirconia heads which had a minimal phase transformation had similar surface roughness and a similar penetration rate of UHMWPE liner as the explanted alumina head.

Polyethylene wear rates with Zirconia and cobalt chrome heads in the ABG hip

We report a radiological analysis of 281 primary cementless ABG total hip arthroplasties performed between 1991 and 1994, with a mean follow-up of 78 months. We compare the polyethylene wear in hips with Zirconia ceramic heads manufactured prior to the introduction of hot isostatic pressing and hips with cobalt chrome heads. The mean linear wear rate was 0.19 mm/yr with 28mm Zirconia heads (n=203), 0.20 mm/yr with 32mm Zirconia heads (n=47) and 0.14mm/yr with 28mm cobalt chrome heads (n=31). We matched each of the 31 patients with 28mm cobalt chrome heads with a patient from the 28mm Zirconia group for gender and age. The mean linear wear rates in these two groups were 0.14mm/yr and 0.19mm/yr respectively (p<0.05). There were 19 revisions for osteo-lysis in 250 hips with Zirconia heads (7.6%) and no revisions in 31 hips with metal heads. We advocate regular review of patients with Zirconia on polyethylene bearing surfaces due to the high linear wear rates and associated osteolysis. (Hip International 2005; 15: 63-70).

Polyethylene wear rates with Zirconia and cobalt chrome heads in the ABG hip.

We report a radiological analysis of 281 primary cementless ABG total hip arthroplasties performed between 1991 and 1994, with a mean follow-up of 78 months. We compare the polyethylene wear in hips with Zirconia ceramic heads manufactured prior to the introduction of hot isostatic pressing and hips with cobalt chrome heads. The mean linear wear rate was 0.19 mm/yr with 28mm Zirconia heads (n=203), 0.20 mm/yr with 32mm Zirconia heads (n=47) and 0.14mm/yr with 28mm cobalt chrome heads (n=31). We matched each of the 31 patients with 28mm cobalt chrome heads with a patient from the 28mm Zirconia group for gender and age. The mean linear wear rates in these two groups were 0.14mm/yr and 0.19mm/yr respectively (p<0.05). There were 19 revisions for osteo-lysis in 250 hips with Zirconia heads (7.6%) and no revisions in 31 hips with metal heads. We advocate regular review of patients with Zirconia on polyethylene bearing surfaces due to the high linear wear rates and associated osteolysis. (Hip International 2005; 15: 63-70).

Retrieval Study of Total Hip Arthroplasty with Use of a Cemented Polyethylene Cup and a Non-cemented Polyethylene Liner in Combination with Zirconia Ceramic Femoral Head: Report of 2 Cases

Catastrophic failure of a zirconia head with Hylamer acetabular component and early failure due to the phase transformation of zirconia ceramic head after total hip arthroplasty have been indebted issues. We report two cases who had failure of the zirconia ceramic head with polyethylene articulations shortly after total hip arthroplasty. Revision retrieval studies were performed subsequently.

A Comparative Study of the in vivo Wear of Zirconia and Metal Heads Articulating with Polyethylene Liners in Total Hip Arthroplasty

Purpose: The purposes of this paper was to determine the wear rates and volumetric wears of ceramic (Zirconia) and metal (Cobalt-chrome) femoral heads, and to differentiate creep from true wear. Another purpose was to determine the extent of wear and volumetric wear per annum. Materials and Methods: We examined 86 patients (111 hips) who were continuously followed up from 180 patients (225 hips) who received THRA with AVN of stage III or above at our hospital. Patients were followed until December 1999 for more than a minimum of 3 years from June for 1996. The hip joint AP radiographs that had been taken immediately after the operations, six weeks postoperatively and annually thereafter were compared. We used the computer assisted vector wear analysis program of Martell to measure the wear rate, volumetric wear and vector wear. Results: The wear rate and the volumetric wear in the zirconia ceramic head group (1.443 mm/year, 665.433 /year) and metal head group (2.161 mm/year, 1271.831 /year) were high immediately after operation and six weeks postoperatively, and this was significantly more than during all for other periods, giving a wear rate and volumetric wear in the ceramic head group of 0.180 mm/year and 81.101 /year, and in the metal head group of 0.219 mm/year and 124.149 /year. Moreover, the average wear rates and volumetric wear rates of these two groups were significantly different, and annual wear and volumetric wears showed a trend to decrease with time. Conclusion: Wear rate and volumetric wear six weeks after operation were remarkably high compared with the other periods. This is interpreted as the result of a creep phenomenon, which occurred mainly during the six weeks following the operation. The Zirconia ceramic head group showed little wear, which confirms the theoretical advantage of the zirconia ceramic head in vivo.

Catastrophic failure of the Elite Plus total hip replacement, with a Hylamer acetabulum and Zirconia ceramic femoral head

We report catastrophic early failure of a cemented total hip replacement comprising a modular femoral component with a Zirconia ceramic head and an acetabular component of cross-linked ultra-high molecular-weight polyethylene (Hylamer). Between 1995 and 1999 we implanted 29 hips in 26 patients with a mean age of 49.2 years. Survivorship analysis in this group revealed a failure rate of 67.6% at five years. All hips which failed did so because of aseptic loosening with progressive osteolysis or radiolucencies. We therefore recommend early and regular review of all patients with this combination of implants and early revision surgery in order to avoid massive bone loss.

Catastrophic failure of the Elite Plus total hip replacement, with a Hylamer acetabulum and Zirconia ceramic femoral head.

We report catastrophic early failure of a cemented total hip replacement comprising a modular femoral component with a Zirconia ceramic head and an acetabular component of cross-linked ultra-high molecular-weight polyethylene (Hylamer). Between 1995 and 1999 we implanted 29 hips in 26 patients with a mean age of 49.2 years. Survivorship analysis in this group revealed a failure rate of 67.6% at five years. All hips which failed did so because of aseptic loosening with progressive osteolysis or radiolucencies. We therefore recommend early and regular review of all patients with this combination of implants and early revision surgery in order to avoid massive bone loss.

Three-body wear of UHMWPE acetabular cups by PMMA particles against CoCr, alumina and zirconia heads in a hip joint simulator

Three-body abrasive wear of ultra-high molecular weight polyethylene (UHMWPE) acetabular cups by loose polymethyl methacrylate (PMMA) bone cement particles is an important mechanism responsible for elevated wear debris generation in total hip arthroplasty. The resistance of the femoral head material to third-body damage has been considered critical for the wear performance of the polyethylene component. This study examines the effect of loose bone cement particles on the wear rate of UHMWPE acetabular cups against both metal and ceramic counterfaces in a hip joint simulator. Against the CoCr head, the UHMWPE cup showed a strong dependence of wear rate on the concentration of the PMMA particles in the lubricant. At a concentration less than 5g/l, the presence of the PMMA particles had no detrimental effect on the wear rate; higher concentrations of the PMMA particles greater than 5g/l led to an accelerated wear of the acetabular cups. Mild scratching damage was observed on the CoCr heads after testing with all PMMA-containing lubricants. However, no increased UHMWPE wear rate was found against these damaged femoral heads in a fresh lubricant without PMMA particles, indicating that femoral head scratching was not a major cause for the elevated wear observed under the three-body abrasive conditions. Against both alumina and zirconia ceramic heads, the wear rate of the UHMWPE was independent of the concentration of the PMMA particles. It was observed that a significant portion of the CoCr heads was covered with loose patches of PMMA particles. The higher the concentration of the PMMA particles, the greater the area of the head covered with PMMA particles. The attachment of PMMA particles to the ceramic heads was much reduced compared to the CoCr heads. It is therefore concluded that ceramic femoral heads are effective against potential run-away wear of the UHMWPE acetabular cups when an excessive amount of loose PMMA particles are present in the lubricant.

Phase transformation of a zirconia ceramic head after total hip arthroplasty

We report two cases of surface deterioration of a zirconia ceramic femoral head associated with phase transformation after total hip arthroplasty. One head was retrieved at revision due to recurrent dislocation after six years and the other because of failure of the locking mechanism of the polyethylene liner after three years. The monoclinic content of the zirconia ceramics rose from 1% to about 30% on the surface of the heads. SEM revealed numerous craters indicating extraction of the zirconia ceramics at the surface. Surface roughness increased from an initial value of 0.006 3m up to 0.12 3m. This is the first report to show that phase transformation of zirconia ceramics causes deterioration of the surface roughness of the head in vivo after total hip arthroplasty.

Short term wear rate of acetabular component in cemented THR with &#198; 22mm zirconia ceramic head

Short term wear rate of acetabular component in cemented THR with <font face="symbol">&#198;</font> 22mm zirconia ceramic head

ジルコニア骨頭人工股関節置換術の臨床的検討

We performed clinical and radiological studies in 36 hip prosthesis with a zirconia ceramic head and in 30 with a metal head from 1989 to 1997. The average postoperative JOA score and reduction of the diameter of the polyethylene were not significantly different between the two groups. A longer follow-up study is necessary to achieve the desired effects of hip prosthesis with a zirconia ceramic head.

Carbon fiber reinforced polyether ether ketone composite as a bearing surface for total hip replacement

This paper investigates the tribological performance of a carbon fiber reinforced PEEK composite as a bearing surface for total hip replacement. Extensive hip joint simulator tests were conducted to optimize the microstructure of the composite and the counterface material. A softer and more graphitic carbon fiber is preferred to a harder and more abrasive fiber. A ceramic counterface is preferred to a metal counterface. An excellent wear couple was identified to be a 30 wt% pitch-based carbon fiber reinforced PEEK composite acetabular insert articulating against a zirconia ceramic head. When tested on a hip simulator run for 10 million cycles, a reduction in the wear rate of almost two orders of magnitude was achieved with this wear couple in comparison to a conventional UHMWPE/metal or UHMWPE/ceramic couple.

Wear of ultra-high molecular weight polyethylene acetabular cups in a physiological hip joint simulator in the anatomical position using bovine serum as a lubricant.

The Leeds physiological anatomical (PA) hip joint simulator was developed to apply three axes of loading and a complex three-dimensional motion so that the forces and motions can reproduce exactly the walking cycles defined by Paul. This paper presents the results of a study using the Leeds PA hip joint simulator to determine the wear of 32 mm ultra-high molecular weight polyethylene (UHMWPE) acetabular cups against stainless steel and zirconia ceramic heads, using bovine serum as lubricant. These results have been compared with the results of a previous study that used water as the lubricant, which led to UHMWPE transfer film being formed on the stainless steel head. Comparisons are also made with clinical results and results from other simulators. The study indicates that it is preferable to use bovine serum in simulator studies. In addition, the results indicate that if the surface roughness of the metallic and femoral heads are similar, and they remain undamaged during the tests, the wear rates of the UHMWPE cups are likely to be similar.

Research and development of alumina and zirconia artificial hip joint

The object of the experiments was to discover the static and dynamic load-carrying capacity of a prosthetic system consisting of a titanium alloy stem, zirconia ceramic ball head and UHMWPE (ultra-high molecular weight polyethylene) socket molded in the ceramic shell, the latter two were both of 22 mm in diameter. The components of the artificial hip joint were placed in a vertical position and load was applied, alternating between 0 and 10 kN and then 12 kN with a frequency of 30 Hz under Ringer's solution up to 10 7 cycles respectively. After 2 × 10 7 cycles there was no sign of damage to be observed among the system tested using the joint simulator. This seems to be a very high safety factor compared with loads occurring in vivo.