Different types of highly cross-linked polyethylene (HXLPE) have been introduced widely in acetabular cups in hip prostheses to reduce the incidence of wear debris-induced osteolysis. Also, we reported that HXLPE cups with 28-mm alumina ceramic femoral head exhibited lower wear than conventional PE cups. Recently, the combination of HXLPE cup and larger diameter femoral head is used widely to prevent dislocation. In this study, we examined the wear of HXLPE with 32-mm alumina ceramic femoral head and compared it with the wear of HXLPE with 28-mm alumina ceramic femoral head. The in vivo wear of 60 HXLPE cups (Aeonian; Kyocera Corp., Kyoto, Japan, currently Japan Medical Materials Corp., Osaka, Japan) with 28-mm alumina ceramic femoral head with clinical use for 3.1–9.1 years (mean 7.4 years) and eight HXLPE cups with 32-mm alumina ceramic femoral head used for 2.3–3.2 years (mean 2.8 years) were examined by radiographic analysis. The early wear rate for the first year of HXLPE cups with 28-mm and 32-mm alumina ceramic femoral head were 0.24±0.10 mm/year and 0.29±0.12 mm/year respectively. There was no significant difference in both femoral head groups (p>0.05). The steady wear rate after 1 year were 0.001±0.03 mm/year and −0.03±0.10 mm/year respectively. There was no significant difference either in both femoral head groups (p>0.05). These findings from this radiographic analysis suggest that the early wear rate in the first 1 year probably represents the creep deformation in bedding-in stage; and the steady wear rate after 1 year probably represents mainly the wear than of the creep deformation. By the radiographic analysis, HXLPE cups in both femoral head groups exhibited low steady wear rate. In conclusion, we expect that the combination of HXLPE cup and 32-mm diameter alumina ceramic femoral head has favorable wear properties with possibility of prevention of dislocation in long-term clinical use

Aseptic loosening induced by wear debris of polyethylene (PE) is the most common cause of long-term total hip arthroplasty failure. In the previous studies, we reported that the protruding contour and surface morphology of metallic femoral head brought an increase of PE wear. Alumina ceramics is advantageous (neutral shape and smooth surface) for precision machining compared with metal materials, because hardness of ceramics is higher than that of metal materials. In this study, we measured the roundness and the roughness of retrieved alumina ceramic and metallic heads, aiming to evaluate the change of surface morphology of those heads in vivo. Fourteen retrieved alumina ceramic femoral heads (Kyocera Corp., currently Japan Medical Materials Corp.) were examined: ten femoral heads were made of small grain-size alumina ceramic (SG-alumina; mean grain size is 3.4 um) with a diameter of 28 mm, with clinical use for 16–28 years (mean 22 years) and four femoral head was made of extra-small-grain size alumina ceramic (XSG-alumina; mean grain size is 1.3 um) with a diameter of 26 mm, with clinical use for 14–19 years (mean 16 years). Six retrieved metallic femoral heads with average clinical use for 12–28 years (mean 18 years) were examined: a diameter of from 22 to 32 mm (e.g. Zimmer Inc., Stryker Corp.) The roundness of the retrieved femoral heads was measured by a contour tracer. The surface roughness in the contact area and the non-contact area of the retrieved femoral heads was measured by a surface roughness tester. Out-of-roundness of SG-alumina and XSG-alumina heads was 0.15 um and 0.19 um, respectively. In contrast, that of metal heads was 2.43 um, and the profiles were in wide distortion compared with both alumina heads. The surface roughness was 0.012 um in the contact area, and 0.009 um in the non-contact area of retrieved SG-alumina heads. The surface roughness in the contact area, 0.007 um, of XSG-alumina was slightly higher than that in the non-contact area, 0.003 um, and the both area of XSG-alumina represent lower value than SG-alumina, with all alumina heads having a reentrant surface profile. In contrast, the surface roughness of metallic heads was in a range of 0.003–0.053 um and several heads showed the protrusion surface profile. In this retrieval study, the roundness and the roughness of both alumina ceramic femoral heads after long-term clinical use were low and stable compared with metallic heads. And also, the surface roughness increased in the order of XSG-alumina < SG-alumina < metallic head. The alumina ceramic femoral head showed the reentrant surface whereas the metallic head showed the protruding surface. When third-body wear occurs during the clinical use, generally reentrant form may occur on the ceramic surface whereas protrusion form may occur on the metallic surface. We have good clinical results more than 20 years using the SG-alumina, and clinical results for a long term will be expected with XSG-alumina of improved microstructure

Trabecular materials show great promise for soft-tissue attachment to prosthetic implants. Results with Tantalum have been very encouraging, however, it remains unclear if this in-growth is secondary to the specific metal or its generic structure,. If structure, is there a specific tolerance with respect to porosity and pore size? In a canine model, bulk blocks of porous alumina ceramic were shown to be completely ingrown by four weeks. The type material was not a factor, and effect of pore size revealed that there is a wide tolerance in facilitating in-growth with the larger pores having the greatest attachment strength (p=0.004). This study examines the in-vivo soft tissue in-growth potential of porous alumina ceramic and the effect of three distinct pore size ranges on this process. Alumina ceramic implants of fixed porosity (~ 85%) were designed in three pore size ranges (100–200, 250–400 and 600–800 μM). Using an established canine model, six implants (two of each type) were implanted in the dorsal subcutaneous tissues of tweleve mature canines and examined histologically and mechanically at four, eight and sixteen weeks with respect to type, amount and strength of soft tissue in-growth. Soft tissue in-growth was grossly evident in all implants at each time interval, and in each pore size. Microscopic examination revealed neo-vascularized in-growth throughout the implant, without evidence of inflammation or foreign body reaction. Numerous blood vessels were visible at the implant interface and within the porous alumina ceramic structure. With peel testing, the weakest attachment strength was with the small pore size with no differences between the medium and large pore sizes. An increase of attachment strength in each pore size was observed over time. This study suggests that architecture of porous structures in general, and not the type of material used, confers the biologic activity and that there is a wide tolerance for pore size in facilitating this process in soft tissue in-growth. Further study of other inert foam structures will be useful in further defining the assets and limitations of this genre of trabecular materials as a whole. Funding: Stryker Orthopaedics, Mahwah, NJ. Please contact author for figures, graphs, and/or diagrams

We report the results of our continued review of 11 total hip arthroplasties using 22.225 mm alumina ceramic femoral heads on a Charnley flanged stem, articulating with chemically cross-linked polyethylene. There was an initial bedding-in of up to 0.41 mm at the articular surface in the first two years. This had not progressed further, at a minimum follow-up of 15 years. Radiographically no femoral or acetabular component showed loosening or osteolysis

In total hip arthroplasty (THA), one of concerned issues is osteolysis due to wear debris of ultra-high molecular weight polyethylene (PE) which often leads to aseptic loosening. Reduction of PE wear debris is essential to prevent osteolysis, and different bearing combination as well as improvement of the bearing material itself have been attempted. Hence alumina ceramics was introduced for THA, aiming to reduce PE wear debris. Ceramic on PE couple showed good results in clinical wear compared with metal on PE couples. Highly cross-linked PE (HXLPE) with gamma-ray or electron-beam irradiation followed by thermal treatment has also demonstrated a remarkably low wear in the previous in vitro studies. In in vivo studies, the wear of HXLPE acetabular cups against alumina ceramic femoral head was evaluated to compare with that of conventional PE cups against alumina ceramic femoral head. The in vivo wear of 61 HXLPE cups (Aeonian; Kyocera Corp., Kyoto, Japan, currently Japan Medical Materials Corp., Osaka, Japan) against alumina ceramic femoral head of 28 mm in diameter with clinical use for 2.1–7.1 years (mean 5.6 years) and eight conventional PE cups against an alumina ceramic femoral head of 28 mm in diameter used for 18.7–23.3 years (mean 20.4 years) were examined by radiographic analysis with Vector Works 10.5. The in vivo wear of eight retrieved HXLPE cups with clinical use for 0.9–6.7 years (mean 2.9 years) and 14 retrieved conventional PE cups used for 16.0–28.0 years (mean 22.0 years) were examined by using a three-dimensional coordinate measuring machine. The worn surfaces of retrieved HXLPE and conventional PE cups were observed by a scanning electron microscope. In the radiographic study, penetration rate of alumina head into HXLPE and conventional PE for the first 1 year were 0.24 mm/year and 0.34 mm/year respectively. One year later, the HXLPE showed significant lower penetration rate of 0.001 mm/year than the conventional PE penetration rate of 0.12 mm/year (p< 0.01). By the retrieval analysis, the mean penetration of retrieved HXLPE and conventional PE cups were 0.11 and 2.97 mm, and they were similar to the results by radiographic analysis. In the worn surface of the retrieved HXLPE cups used for around 1 year, machine marks were observed. In contrast, the worn surface of the retrieved HXLPE cups used for more than five years were smooth, and furthermore, in high magnification observation they had wear morphology different from conventional PE. These findings from this retrieval study suggest the penetration in the first 1 year detected by radiographic measurement was probably caused by creep deformation in bedding-in stage; and 1 year after, the penetration was probably caused mainly by wear. By the radiographic analysis, HXLPE cups against alumina ceramic femoral head has a 99 % lower wear rate compared with conventional PE cups. Also, retrieved HXLPE cups against alumina ceramic femoral head exhibited lower wear compared with conventional PE cups. In conclusion, we expect that the HXLPE cup used with alumina ceramic femoral head has favorable wear properties in long-term clinical use

Introduction and Aims: Recently, concerns have emerged regarding the high stiffness of acetabular components inserted with alumina ceramic liners, which might potentially cause early migration and loosening. This study was designed to investigate in-vivo the migration pattern of these constructs. Method: Fifty patients (50 hips) operated on using the same surgical technique and the same prosthesis were randomised in two groups. The study group of hips was treated with an alumina ceramic liner, the control group of hips received a polyethylene liner. An alumina femoral head with a diameter of 28mm was used in all hips. Radiostereometric analysis (RSA) was performed to assess migration using serial follow-up radiographs. Results: The median pre-operative Harris hip score (HHS) was rated 48.9 points in the alumina group, and 47.7 points in the polyethylene group. At the two-year follow-up, the median HHS of the alumina group was rated 94.1 points, and was rated 93.7 points in the polyethylene group. There were no clinical or radiological signs of aseptic loosening. RSA of the alumina group of cups showed a median axial displacement of 0.026 mm (SD 0.35mm). The median axial displacement of the polyethylene group was 0.047 mm (SD 0.26 mm) (p=0.9). The median tilting of the cup was 0.21 degrees (SD 0.54 degrees) in the alumina group, and 0.35 degrees (SD 0.71 degrees) in the polyethylene group (p=0.12). Conclusion: At an average of two years post-operatively, the cups inserted with an alumina ceramic liner appeared stable, RSA showed low rates of non-progressive migration. Results did not differ from those observed using the same cup inserted with a polyethylene liner

Aim: Alumina ceramic on ceramic bearings have gained popularity in hip arthroplasty due to the properties of low wear, low friction and chemically inert wear debris. In a previous study, we reported the excellent clinical results of a series of cementless ceramic on ceramic primary total hip arthroplasties at a minimum of 5 years. We now present the follow up results at 10 years. Method: Between June 1997 and February 1999, 301 consecutive, primary cementless hip arthroplasties were performed on 283 patients in our unit. The mean age of the patients was 57.8 years, with 145 (51%) being female. All of the hips received the same implant: (Osteonic ABC cup and Secure-Fit or Secure-Fit Plus stem; Stryker Orthopaedics). A third generation alumina ceramic on ceramic bearing (Biolox Forte; CeramTec) was used for articulation in all cases. All the operations were performed through a posterior approach with enhanced posterior repair, and the post-operative protocols were the same for all the patients. The clinical and radiographic outcome at 10 years were analysed. Results: At 10 years, 7.3% had died of unrelated cause and 3% were revised. The average Harris Hip score was 94.3 points at the last follow up. Ninety six percent of patients scored an excellent or good result, with less than 3% have moderate residual pain. Radiographically, all patients assessed had evidence of stable bony ingrowth. There were nine revisions in all, four stem revisions due to periprosthetic fracture, one secondary to aseptic loosening and one to facilitate a femoral shortening osteotomy. There was one cup revision for psoas tendonitis and one for cup repositioning. This same patient subsequently underwent further revision due to acetabular osteolysis with metallosis and some ceramic wear. Overall, the survival rate of the implants was 96% at 10 years. The retrieved femoral heads showed a median wear rate of 0.2 cubic millimeters per year. Conclusions: Alumina ceramic on ceramic bearings in cementless primary total hip arthroplasty had been shown to have good survival rate at 10 years with good function, low wear rate and no adverse radiographic changes. The one case of osteolysis may be due to ceramic wear debris or may be due to metal wear debris from the neck to rim impingement

Wear simulator studies suggest low wear rates of Alumina ceramic femoral heads with polyethylene total hip bearings. Short-term wear and clinical data of ceramic/highly crosslinked ultra-high molecular weight polyethylene (UHMWPE) couples are under reported in the literature. A retrospective review was performed to determine and compare the wear rate for hips implanted with an Alumina ceramic femoral head and X3® poly-ethylene insert to the acceptable polyethylene wear rate in the literature. We evaluated 70 primary total hip replacements performed at one institution, by two surgeons, from February 2006 through June 2007. At a minimum 2 year follow-up, calculated annual wear for the ceramic/X3. ®. polyethylene articulations showed a significant decrease compared to literature reports of 0.1mm/year or greater for conventional polyethylene. Radiographic and clinical outcomes show no loose implants, dislocations, ceramic fractures or revision surgeries at last follow-up. These early findings suggest that ceramic/X3. ®. bearing couples may serve as an acceptable choice for the younger, active patient

Introduction. Cross linked polyethylene (XLPE) has gained popularity as a bearing surface of choice for younger patients despite only medium term results being available for wear rates. Concern remains regarding the long-term stability and durability of these materials. In order to address these issues we present the longest radiological and clinical follow-up of XLPE. Patients/Materials & Methods. Since 1986, we have prospectively studied a group of 17 patients (19 hips) that underwent a cemented Charnley low friction arthroplasty using a combination of 22.225mm alumina ceramic femoral head, a modified Charnley flanged stem and a chemically cross-linked polyethylene cup. We now report the 28 year clinical and radiological results. Results. At the latest review nine patients (11 hips) were still attending for clinical and radiographic follow-up at a mean of 27.5 years (26 – 28). The mean age at surgery in this group was 47 years (26 – 58). Seven patients died whilst still under follow-up, and one was revised at 17 years for late deep infection following urological surgery. There have been no mechanical failures of the components and no aseptic loosening. The mean initial penetration rate at 1 year was 0.13mm/year; between one and four years was 0.034mm/year; and between 4 years and latest follow-up (mean 27.5 years) was 0.007mm/year. One patient in this group subsequently had a contralateral Charnley metal on UHMWPE hip replacement and had a total cup penetration of 6.1mm at 27 years, compared to 0.41mm at 28 years in the XLPE and alumina ceramic combination. Conclusion. The clinical and radiological results in this group of patients remain excellent with no aseptic loosening. There was an initial bedding in period, after which there was an extremely low wear rate. The results highlight the long term stability and durability of cross-linked polyethylene when used in combination with a small diameter alumina ceramic head

A consensus on total hip arthroplasty (THA) concluded that the major remaining issues of concern included the long-term fixation of the joint replacement, osteolysis due to poluethylene (PE) wear debris which often leads to aseptic loosening. Alumina ceramics had been extensively used in medicine, and we started using the alumina ceramic for THA bearing surface in hopes to reduce the PE debris. It was because alumina ceramics is advantageous for precision machining compared with metal materials, and its hardness is higher than that of metal materials. Also, to augment cement–bone bonding, we interposed hydroxyl apatite (HA) granules at the cement–bone interface, so called “Interface Bioactive Bone Cement (IBBC) technique”. HA granules (2–3 g) were smeared on the bone surface of the acetabulum and femur just before cementing. In this study, we evaluated 19–22 years clinical results of THA with alumina ceramic head combined with PE cup fixated IBBC technique. Total 285 joints (212 patients) were implanted by one senior surgeon from January 1986 to December 1988, and 265 joints (192 patients) were traceable. Alumina ceramic femoral head of 28 mm in diameter and acetabular cup of the conventional PE sterilized with ethylene oxide gas were used in all patients. The PE cup and stem were fixed with IBBC technique in all cases. The presence of radiolucent line, loosening and osteolysis were observed using radiograph of the traceable cases. The locations of radiolucent lines were identified according to the zones described by DeLee and Charnley for acetabular cups and the zones described by Gruen et al. for femoral stems. The in vivo wear of 21 PE acetabular cups for 19.0–21.9 years (mean 20.3 years) was measured from the latest radiographs using computer assistant technique with Vector Works 10.5 software. Features of the clinical radiograph images of the IBBC case were classified as follows: the radiolucent line represented “gap” between the HA layer and the cement; the loosening represented “opening” between the HA layer and the cement. For the quantitative analysis, we divided the surrounding bones of the THA into several zones as done in the previous studies. The “gap” appeared in zone 4 in three joints (1.4 %), in zone 3 in two joints (0.9 %) of acetabular cup. In femoral side, in zone 1 in four joints (1.8 %) in zone 7 in one joint (0.4 %). The “opening” appeared in three acetabular cup (1.4 %). Since no opening was appeared in zone 3 or zone 4, however, no re-operation was needed. Images of osteolysis were seen one in zone 1 (0.5 %), and one in zone 2 (0.5 %) in acetabular side and two in zone 1 (0.9 %) of the femur. The mean linear wear rate of PE acetabular cups was 0.13 mm/year. The fixation to the bone by the IBBC technique has been maintained for long term. We think that the result was brought by the biological integration between bone and HA granules. In conclusion, this study has shown satisfactory results of the cemented THA with ceramic head combined with PE cup for 19–22 years

The study was designed to compare the clinical performance of an Alumina ceramic acetabular bearing to that of a polyethylene bearing in a cementless hip couple. The study group consisted of 15 surgeons who performed 308 total hip replacements (297 patients) between January 29, 1998 and February 1, 2000. All patients received a porous coated cementless titanium stem with an Alumina ceramic 28 mm or 32 mm head. Patients were randomized to receive a porous titanium acetabular shell with either a polyethylene or Alumina cup liner. There were 164 Alumina cups and 144 polyethylene cups. The mean age was 57.3 years and consisted of 50% males and 50% females. The preoperative diagnoses were: osteoarthritis 69.8%, avascular necrosis 19.5 %, post traumatic arthritis 2.9 %, inflammatory arthritis 3.9% and other 3.9%. The mean follow up was 12 months. The longest follow up was 38 months. The Harris Hip Score was good and excellent in 86% of the control patients and 87% of the study patients. There has been 100% follow up and survivorship. There were two reoperations for recurrent dislocations in each group. There were no Alumina component fractures, no progressive radiolucencies and no evidence of rapid wear. In the short term follow-up between 12 and 38 months, there do not appear to be any differences between the patients with a bearing couple consisting of Alumina on plastic with those consisting of Alumina on Alumina. There have been no catastrophic failures of the ceramic components. The Alumina/Alumina bearing couple for total hip arthroplasty appears to be an excellent alternative bearing, providing the advantage of improved long term wear and a reduced incidence of polyethylene induced osteolysis

We report the results of our continued review of 14 hip arthroplasties using alumina ceramic femoral heads with cross-linked polyethylene cups. There have been no complications and a very low rate of penetration. This was 0.02 mm per year after an initial ‘bedding-in’ period of two years. There has been no change in the mean rate between our earlier study at six years and the current results at 10 to 11 years. The use of these bearing surfaces appears to reduce the potential amount of polyethylene debris and may provide the next logical stage in the development of the Charnley low-friction arthroplasty

A retrospective study was performed to evaluate the safety and effectiveness of an alumina-based total knee arthroplasty system (Low Friction Anatomical, LFA, Kyocera, Kyoto, Japan). The system, which uses modern materials and contemporary component design, has been in clinical use in Japan since 1992. The system uses an alumina femoral component that articulates against standard polyethylene tibial and patellar components. The retrospective study evaluated the clinical performance of amodern-style ceramic femoral component and included 60 knees (49 patients) with an average follow-up of 3.8 years. Clinical outcomes were assessed by the Japanese Orthopaedic Association (JOA) Knee Rating Scale, which is comparable to the Knee Society Rating Scale used in the United States. Radiographic outcomes were assessed by the operating surgeon and another independent reviewer. The radiographs were reviewed for the presence or absence of lytic lines, implant and anatomical alignment, and other pertinent radiographic findings. Complications during the follow-up period were noted. Total knee replacement with the LFA system improved JOA scores in 98% of the cases. Mechanical and prosthetic alignment were satisfactory for all knees. The following results were noted:. No fractures or failures associated with the alumina ceramic femoral component. No problems with subsidence or abnormal bone remodeling. Absence of lytic lines in 96% of cases. Absence of complication in 94% of cases. Overall success rate of 96% at an average follow-up of 3.8 years. An alumina-based total knee replacement system was found to be a safe and effective means of treating the arthritic knee joint. The use of ceramics in total knee arthroplasty applications provides an opportunity for a low friction bearing interface and a completely metal-free total joint system

We have been using a Charnley type hip prosthesis with an alumina ceramic head. Three sizes of alumina head, 28, 26 and 22mm, were employed and the Ortron 90 Charnley total hip prosthesis was used at the same period. The objective of this study was to compare the survival rate and the wear rate of those four groups. There were 90, 62, 322 and 88 hips in 28, 26, 22mm alumina head and 0rtron 90 head group. Average age at operation was 49.5, 57.8, 58.0 and 60.6, respectively. A 28 mm prosthesis was indicated for relatively young patients. The mean duration of follow-up was 156, 97, 49 and 110 months, respectively. Twenty patients were chosen at random for each of four groups and the linear wear as seen on X-ray film was measured every two years with a computer and scanner. Results: The average linear wear rate (mm/yr) was 0.179 for the 28mm, 0.112 for the 26mm, 0.115 for the 22mm alumina head and 0.075 for the Ortron 90 head. The difference between the 28mm group and the other three groups was analyzed statistically. The Kaplan-Meier survivorship analysis, with revision for aseptic loosening as the endpoint, showed the survival rate of the 28mm group appeared to be inferior to that of the other three groups. Discussion: Our study showed that the wear rate of the 28mm alumina group was highest because low grade alumina was used. In addition, the polyethylene socket used for the 28mm group was thinner than that for the other groups. No clinical superiority of ceramics to metal in terms of polyethylene wear can be shown in this study. A randomized prospective study should be carried out to determine whether an alumina ceramic head is clinically superior to a metallic head in terms of polyethylene wear

Introduction. Wear of the ultra high molecular weight polyethylene (UHMWPE) cup and the resulting loosening has been shown to limit the long-term results of the Charnley low-frictional torque arthroplasty (LFA). Factors affecting wear rates have been studied: level of patient activity, effective roughness of the stainless steel head, impingement and the possible variations in wear characteristics of UHMWPE. Since patients' activity level cannot be predicted or modified, alternative materials were examined. Methods and Results. The Charnley 22.225 mm diameter head of alumina ceramic in combination with chemically cross-linked polyethylene cup has now reached over 23 years of clinical and radiographic follow-up. Of the initial 17 patients (19 hips) in the study, 4 patients (4 hips) have died, 1 hip has been revised for deep infection and 3 patients (3 hips) are unable to attend follow-up due to medical problems unrelated to the hip. Nine patients (11 hips) are still attending follow-up at a mean of 22 years 5 months (21 year 3 months-23 years 6 months). The mean age at surgery in this group was 47 years (26-58) and the mean weight 81kgs (54-102). The mean penetration rate was 0.02mm/year and none have exceeded 0.41mm total penetration. Conclusion. Since the problem of cup wear and loosening is mechanical rather than biological the long-term solutions are more likely to come from materials rather than radical changes of design of methods of component fixation

Alumina ceramic-ceramic bearings have the benefit of very low wear and studies showing the complete absence of osteolysis during the first decade of close study. However, good results depend on several critical factors including surgical exposure, surgical technique, component placement, and choice of component design. The following abstract discusses our experience with several of these factors. Initially, there were concerns that the use of ceramic-ceramic bearings would lead to a higher incidence of hip dislocation since the bearings have fewer femoral head-length choices and the absence of lipped-liners. In our prospective study of 418 hips the incidence of hip dislocation at 1 to 10 year followup is 0.5% (2/418). This experience suggests that the use of alumina ceramic-ceramic bearings is not associated with an increased incidence of dislocation. More recently, concerns about squeaking of alumina ceramic-ceramic bearings have been reported, particularly from centers in the United States. To investigate this issue, we reviewed information on 1275 consecutive revision THAs and 1039 consecutive primary ceramic-ceramic THA that had been performed at two institutions between 1996 and 2007. To identify the influence of the implant design on the incidence of squeaking we divided the primary hips into three groups with group 1: flush mounted ceramic liner; group 2a: recessed ceramic liner mated with a stem made of TiAlV; and group 2b: recessed ceramic liner mated with a stem made of a beta titanium alloy comprised of 12% molybdenum, 6% Zirconium, and 2% Iron. Analysis of the 1275 revision hips revealed 5 alumina ceramic-ceramic hips in patients who complained of squeaking or grinding. All 5 hips were designs that included a ceramic liner that was recessed inside of an elevated metal rim. All 5 hips also demonstrated metallosis at the time of revision. In primary THA, Group 2b had statistically significantly more squeaking (9 of 118) than group 2a (10 of 321) which had statistically significantly more squeaking than group 1 (6 of 700). In addition, the severity of squeaking between the groups was qualitatively different. Patients in Group 2b who complained of squeaking would often experience squeaking frequently throughout the day and could be demonstrated in the physician’s office. By contrast, patients in Group 1 who noted squeaking stated that the hip squeaked once a day to once a year. No patient in Group 1 complained of frequent squeaking or could demonstrate squeaking in the physicians’ office. Further, joint fluid analysis from a patient in Group 2b who complained of squeaking revealed metal from both the femoral (Molybdenum) and acetabular (Aluminum) components. As reported in another abstract at this meeting, 10 year survivorship of flush-mounted alumina ceramic-ceramic THA is 98.4% (95% confidence interval 97.1–100%) and no patient in that prospective clinical studies demonstrated radiographic evidence of osteolysis or wear. These experiences demonstrate that THA using alumina ceramic-ceramic is extremely reliable with low revision and dislocation rates and an absence of osteolysis. Significant squeaking is not associated with flush-mounted alumina ceramic liners and is clearly associated with elevated metal rims and metallosis. Finally, squeaking is statistically significantly associated with femoral components made of a beta titanium alloy consisting of Titanium, Molybdenum, Aluminum, and Iron

We report the results of our continued review of 11 hip arthroplasties using 22.225mm alumina ceramic femoral heads (CCH) on a Charnley flanged stem articulating with a chemically cross-linked polyethylene (XLPE) cup. The initial bedding-in of up to 0.41mm, which was reached within about 2 years, has not progressed further with a follow up to 18.1 years. The mean total penetration of the XLPE cup for this group of patients is 0.31mm (0 – 0.41) and a penetration rate of 0.019 mm/year (mean 0 – 0.026). One patient with CCH/XLPE arthroplasty on the left side and a conventional metal on ultra high molecular weight polyethylene (UHMWPE) on the right side, has a ten fold difference in total penetration: 0.41mm compared with 4.1mm and a year shorter follow-up. The mean age of the 9 patients (11 hips) attending was 47.2 years (26–58) at the operation and is now 64 years (42–73). Clinical results remain excellent with freedom from pain and normal activity level appropriate to their age and gender. Radiographically none of the cups or stems show evidence of loosening or osteolysis and there have been no problems that could have been attributed to the materials or the design used

Hypersensitivity to metal alloy orthopaedic implants has become identified increasingly as a cause of implant failure. Because of their hypoallergenic properties, ceramic materials have been recommended as an alternative to metals. Unfortunately, the cost of ceramics and limitations imposed by their material properties has restricted these applications. The metalloceramic composite Oxinium® has been suggested as asubstitute. This is the first study to prospectively compare these materials in patients with documented cobalt-chrome hypersensitivity. Over a period of ten years, preoperative screening using skin patch testing and in vitro leukocyte stimulation testing of patients with gonarthrosis and a history of metal hypersensitivity identified sixteen patients with allergy to cobalt-chrome alloy. Twelve (all& ) underwent primary, and four underwent revision (3& , 1%) knee replacement surgery using either alumina ceramic femoral components (3 primary, 2 revisions) or Oxinium® femoral components (9 primary, 2 revisions) All implants were fixed with acrylic cement, and all-polyethylenetibial implants were used in each procedure. None of the patients in the primary groups developed symptoms of allergic reaction at a minimum of one year following surgery. Serial serum antibody and leukocyte stimulation studies have shown no reaction following placement of either type of prosthetic knee. Those undergoing revision surgeries had rapid resolution of preoperative symptoms of pain, effusion and eczematous rash. Serum studies showed a concomitant fall inantibody levels. The two patients undergoing revision surgery with alumina femoral implants subsequently underwent second revisions (both at 8 years) using Oxinium® femoral implants. Neither developed clinical symptoms orchanges in antibody profile. While the number of patients in the present study is relatively small, it is the only independent, prospective, clinical comparison of these materials. The uniformly good results suggest implants of Oxinium® offer the hypoallergenic properties of alumina without adverse-material properties and at a lower cost

Ultra high molecular weight polyethylene (UHMWPE) was introduced into clinical practice by Charnley in November 1962 and has remained the standard material for the hip and other total joint arthroplasties. Wear of the UHMWPE cup, although studied from the beginning, did not appear to be a clinical problem although Charnley suspected that this would be so in the long term. A review of the outcome of the Charnley low-friction arthroplasty in patients under the age of 40 years at the time of the operation has shown that the incidence of cup migration was exponentially related to the depth of cup penetration. A prospective study using 22.225 mm alumina ceramic (Al 20 3 ) head articulating with cross linked polyethylene was set up with the initial penetration of 0.2 – 0.4 mm in about 2.5 years with no further penetration. The clinical results mirrored closely the experimental results obtained with the identical set of materials and design. The clinical results have now reached 14 year follow-up and the initial total penetration of 0.2 – 0.4mm has remained unchanged. Review of long term results of the Charnley LFA has shown a mean penetration rate of 0.1 mm/year (0.02 – 0.6). With a mean penetration rate of 0.1 mm/year, the revision rate for cup wear and loosening in patients under the age of 50 at the time of the LFA, and with a follow-up to 32 years, is in the region of 10%. If the penetration rate remained at 0.02 mm/year or less then no cups have been revised for aseptic loosening. Ceramic / UHMWPE articulation is the next stage of evolution of the Charnley LFA. A prospective study using zirconia 22.225 mm head is approaching 7 year follow-up in over 1000 cases

Introduction. Total elbow arthroplasty (TEA) is a widely accepted for the treatment for damaged rheumatoid elbows to achieve sufficient joint function. The current prospective study reports the long term follow-up of TEA with an unlinked stem type (Stemmed Kyocera type I, SKC-I) with a solid trochlea on patients who have rheumatoid arthritis (RA). SKC-1 is derived from an unlinked surface replacement prosthesis using polycrystalline alumina ceramics on high-density polyethylene (Kyocera type I), which was developed in 1979, based on the measurement study on the cadaveric elbows. Materials and Methods. 57 elbows (Larsen’s grade IV and V) from 45 RA patients replaced by SKC-1 were investigated. Cement fixation was used in all cases. The duration of follow-up ranged from 36 to 154 (average 73. 7) months. The clinical condition of each elbow before and after operation was assessed according to the scoring system of Japanese Orthopaedic Association (JOA) elbow scoring system (maximum 100 points), which is composed of scores for pain, activity of daily life, muscle strength, range of motion, instability, and deformity of the joint. On the basis of this system, the results are defined as excellent (90–100 points), good (75–89), fair (60–74), and poor (< 60). Radiographic loosening was defined as a progressive radiolucent line of more than two millimeters that completely surrounded the prosthesis. Results. The average postoperative JOA score improved from 43. 5±10. 2. °. to 81. 0±}10. 3. °. , with marked pain relief. The mean range of motion (ROM) of extension/flexion before the surgery was –35. 7±}22. 4/117. 1±}19. 1. °. and at last follow-up was −17 5±}12. 7/136. 3±}11. 4. °. The mean ROM of pronation /supination improved from 51. 1±}23. 4/56. 5±}28. 5. °. to 78. 3±}16. 8/82. 3±}16. 5. °. Of the 57 elbows, 9 elbows were judged to have excellent results, 37 had good results, 8 had fair results, and 3 had poor results. There were no instances of ulnar nerve palsy, triceps avulsion, or postoperative infection. Medial or lateral epicondylar fracture occurred in 2 cases during the operation, and union was achieved 3 months later. Massive instability with joint dislocation was seen in 3 cases of mutilans arthritis, resulting in poor results. Aseptic loosening was seen in 3 elbows. Revision surgery was performed in 1 case of accidental post-operative distal humerus fracture, and in another of olecranon fracture with the breakage of the ulnar component. With loosening defined as the end point, Kaplan-Meier curve of the cumulative probability of survivorship demonstrates the likelihood of survival of the prosthesis at 93. 8 percent for as long as 10 years. Discussion. The results of the current study showed a high reliability of the SKC-1 prosthesis with the novel alumina ceramic component over a long period when implanted with cement. However, the use of non-constrained devices is limited by the amount of bone and by the need for ligamentous stability. If soft tissues are damaged along with marked bone loss or inflammatory changes, the ligament should be repaired or a semiconstrained type of prosthesis is indicated. It is important to note that a high level of surgical technique is required for TEA in RA elbows to avoid typical postoperative complications