Ceramic-on-ceramic Bearings Research Articles

Cementless total hip arthroplasty using Biolox®delta ceramic-on-ceramic bearing in patients with osteonecrosis of the femoral head.

The purpose of this study was to evaluate the results of cementless total hip arthroplasty (THA) using a 32 mm or larger Biolox®delta ceramic-on-ceramic (CoC) bearing in patients with osteonecrosis of the femoral head after a minimum of 5 years of follow-up. We retrospectively analysed 44 patients (53 hips) who underwent cementless THA using Biolox®delta CoC bearing. There were 33 men (40 hips) and 11 women (13 hips) with the mean age of 49 years. A 36 mm head was used in 42 (79%) of 53 hips and a 32 mm head was used in 11 hips with smaller acetabular shells. The mean duration of follow-up was 5.3 years (range 5-6 years). The mean Harris Hip Score improved from 50 points preoperatively to 97 points at final follow-up (p<0.001). All acetabular and femoral components showed radiographic evidence of osseointegration. No osteolysis was observed. No patients sustained ceramic fracture. An audible hip noise was identified in 2 (4%) of the 53 hips (1 squeaking and 1 clicking). Survivorship with revision for any reason at a minimum of 5 years was 100% in the best-case scenario and 95 % in the worst-case scenario. The minimum 5-year results of cementless THA using a 32 mm or larger Biolox®delta CoC bearing in patients with osteonecrosis of the femoral head were encouraging with excellent survivorship. However, it was also found that the risk of noise development remains even for the new alumina matrix composite ceramic.

Outcomes of Ceramic Bearings After Revision Total Hip Arthroplasty in the Medicare Population

BackgroundThe purpose of this study was to analyze the utilization and outcomes of ceramic bearings used in revision total hip arthroplasty (R-THA) in the Medicare population. MethodsA total of 31,809 patients aged >65 years at the time of revision surgery who underwent R-THA between 2005 and 2013 were identified from the United States Medicare 100% national administrative claims database. Outcomes of interest included relative risk of readmission (90 days) or infection, dislocation, rerevision, or mortality at any time point after revision. Propensity scores were developed to adjust for selection bias in the choice of bearing type at revision surgery. ResultsThe utilization of ceramic-on-polyethylene (C-PE) and ceramic-on-ceramic (COC) bearings in R-THA increased from 5.3% to 26.6% and from 1.8% to 2.5% in between 2005 and 2013, respectively. For R-THA patients treated with C-PE bearings, there was reduced risk of 90-day readmission (hazard ratio, HR: 0.90, P = .007). We also observed a trend for reduced risk of infection with C-PE (HR: 0.88) that did not reach statistical significance (P = .14). For R-THA patients treated with COC bearings, there was reduced risk of dislocation (HR: 0.76, P = .04). There was no significant difference in risk of rerevision or mortality for either the C-PE or COC bearing cohorts when compared with the metal-on-polyethylene bearing cohort. ConclusionMedicare patients treated in a revision scenario with ceramic bearings exhibit similar risk of rerevision, infection, or mortality as those treated with metal-on-polyethylene bearings. Conversely, we found an association between the use of specific ceramic bearings in R-THA and reduced risk of readmission (C-PE) and dislocation (COC).

Analysis of the Friction-Induced Squeaking of Ceramic-on-Ceramic Hip Prostheses Using a Pelvic Bone Finite Element Model

Total joint arthroplasty is regarded as a significant advance in the treatment of painful and disabling joint pathologies. Ceramic-on-ceramic (CoC) artificial joints have been shown to produce substantially less wear debris than traditional metal-on-polyethylene bearings. However, with the recent increase in popularity of CoC bearing, postoperative audible squeaking has become a recognized clinical complication. Although the nature of squeaking is a multifactorial combination of interaction among patient, surgery and implant, it is generally agreed that friction is the driving force inducing the vibration and sound emission. Thus, biotribologically induced acoustic issues have become the new problems for CoC artificial joints. In this study, a finite element model containing human pelvis, ceramic hip endoprosthesis and femur is established to analyze the mechanism of clinical squeaking phenomenon in CoC artificial joints. Complex eigenvalue method is used to study friction-induced dynamic response of the whole model. By comparing the vibration characteristics of all the components, the generation mechanism of squeaking is discussed. Results show that the main cause of the squeaking is the bending and torsional resonance of the femoral component, while pelvis is involved in the sound emission as well.

Ceramic on ceramic arthroplasty of the hip

The leading indication for revision total hip arthroplasty (THA) remains aseptic loosening owing to wear. The younger, more active patients currently undergoing THA present unprecedented demands on the bearings. Ceramic-on-ceramic (CoC) bearings have consistently shown the lowest rates of wear. The recent advances, especially involving alumina/zirconia composite ceramic, have led to substantial improvements and good results in vitro. Alumina/zirconia composite ceramics are extremely hard, scratch resistant and biocompatible. They offer a low co-efficient of friction and superior lubrication and lower rates of wear compared with other bearings. The major disadvantage is the risk of fracture of the ceramic. The new composite ceramic has reduced the risk of fracture of the femoral head to 0.002%. The risk of fracture of the liner is slightly higher (0.02%). Assuming that the components are introduced without impingement, CoC bearings have major advantages over other bearings. Owing to the superior hardness, they produce less third body wear and are less vulnerable to intra-operative damage. The improved tribology means that CoC bearings are an excellent choice for young, active patients requiring THA.

Isolated revision of an acetabular component to a ceramic-on-ceramic bearing in patients under 50 years of age.

A number of studies have reported satisfactory results from the isolated revision of an acetabular component. However, many of these studies reported only the short- to intermediate-term results of heterogeneous bearing surfaces in a mixed age group. We present our experience of using a ceramic-on-ceramic (CoC) bearing for isolated revision of an uncemented acetabular component in 166 patients (187 hips) who were under the age of 50 years at the time of revision. There were 78 men and 88 women with a mean age of 47.4 years (28 to 49). The most common reason for revision was polyethylene wear and acetabular osteolysis in 123 hips (66%), followed by aseptic loosening in 49 hips (26%). We report the clinical and radiological outcome, complication rate, and survivorship of this group. The mean duration of follow-up was 15.6 years (11 to 19). The mean pre-operative Harris hip score was 33 points (1 to 58), and improved to a mean of 88 points (51 to 100) at follow-up. The mean pre-operative total Western Ontario and McMaster Universities Osteoarthritis Index score was 63.2 (43 to 91) and improved to 19.8 points (9 to 61) post-operatively. Overall, 153 of 166 patients (92%) were satisfied with their outcome. Kaplan-Meier survivorship analysis, with revision or radiological evidence of implant failure (13 patients, 8%) as end-points, was 92% at 15 years (95% confidence interval 0.89 to 0.97). Isolated revision of a cementless acetabular component using a CoC bearing gives good results in patients under 50 years of age.

Are ceramic-on-ceramic bearings in total hip arthroplasty associated with reduced revision risk for late dislocation?

Dislocation is a major complication after primary total hip arthroplasty (THA), but little is known about the potential relationships between bearing materials and risk of dislocation. Dislocation within the first year after surgery is typically related to either surgical error or patient inattention to precautions, but the reasons for dislocation after the first year are often unclear, and whether ceramic bearings are associated with an increased or decreased likelihood of late dislocation is controversial. The purpose of this study was to use a national registry to assess whether the choice of bearings-metal-on-polyethylene (MoP), ceramic-on-polyethylene (CoP), ceramic-on-ceramic (CoC), or metal-on-metal (MoM)-is associated with differences in the risk of late dislocation. Data from primary THAs were extracted from the New Zealand Joint Registry over a 10-year period. The mean age of patients was 69 years (SD ± 12 years), and 53% were women. The median followup in this population was 7 years (range, 1-13 years). The surgical approach used was posterior in 66% of THAs, lateral in 29%, and anterior in 5%. The primary endpoint was late revision for dislocation with "late" defined as greater than 1 year postoperatively. A total of 73,386 hips were available for analysis: 65% MoP, 17% CoP, 10% CoC, and 7% MoM. In general, patients receiving CoC and MoM bearings were younger compared with patients receiving CoP and MoP bearings. Four percent of the hips were revised (3130 THAs); 867 THAs were revised for dislocation. Four hundred seventy THAs were revised for dislocation after the first postoperative year. After adjusting for head size, age, and surgical approach, only CoP (hazard ratio [HR], 2.10; p = 0.021) demonstrated a higher proportion of revision, whereas MoP did not (HR, 1.76; 95% p = 0.075). There were no differences of revisions for dislocation in the CoC (HR, 1.60; p = 0.092) and MoM cohorts (HR, 1.54; p = 0.081). Dislocation is a common reason for revision after THA. The relationships between bearing materials and risk of revision for late dislocation remain controversial. This large registry study demonstrated that bearing surface had little association with the incidence of late dislocation. Future studies with longer followups should continue to investigate this question. Level III, therapeutic study.

Ceramic on ceramic hip arthroplasty in fused hips.

Background:Most literature in the field of total hip arthroplasty (THA) for fused hips, until date has reported the results of using metal on polyethylene and ceramic on polyethylene bearings. Results of THA using ceramic on ceramic (CoC) bearings in fused hips have not been published in literature. This study reports the results of cementless THA using CoC articulation perfomed in fused hips.Materials and Methods:Twenty-three patients (25 hips) with fused hips underwent conversion to THA using CoC bearings and were followed up for a mean 5.4 years. The conventional posterolateral approach was used in 15 hips, a modified two incision technique in 7 hips and a direct lateral approach with greater trochanteric osteotomy in 3 hips. Postoperatively, range of motion exercises were encouraged after 2–3 days of bed rest and subsequent gradual weight bearing using crutches was begun.Results:Mean Harris hip score improved from 42.4 to 84.2 and mean leg lengthening of 36.6 mm was achieved. In the average 5.4 years (range 2.8-9.1 years) followup there were no cases with osteolysis around acetabular cup and femoral stem. In this study, there was no case of ceramic fracture. There was one case of squeaking.Conclusion:This study suggests that cementless THA performed for fused hips with CoC bearings can provide good early clinical results.

Midterm Outcomes of the Recently FDA Approved Ceramic on Ceramic Bearing in Total Hip Arthroplasty Patients Under 65 Years of Age

The present study aimed to evaluate the mid-term results of the fourth generation of ceramic on ceramic (CC) bearing. Demographics, surgical technique, complications, clinical and radiologic outcomes were analyzed in a series of 133 consecutive CC total hip arthroplasties (THAs) with a newest generation CC bearings to determine if these provide safe and well performing bearings. At the last follow-up, there were no cases of ceramic fracture or chipping and no revision surgery necessary for bearing related complication. One hip underwent two staged revision for infection and another underwent revision for dislocation, resulting in an overall 98.5% survival rate at a mean of 6 years. The newest generation of CC bearings provides a reliable and safe bearing in young, active patients undergoing THA.

Comparison of the risk of revision in cementless total hip arthroplasty with ceramic-on-ceramic and metal-on-polyethylene bearings

Background and purpose — Ceramic-on-ceramic (CoC) bearings were introduced in total hip arthroplasty (THA) to reduce problems related to polyethylene wear. We compared the 9-year revision risk for cementless CoC THA and for cementless metal-on-polyethylene (MoP) THA.Patients and methods — In this prospective, population-based study from the Danish Hip Arthroplasty Registry, we identified all the primary cementless THAs that had been performed from 2002 through 2009 (n = 25,656). Of these, 1,773 THAs with CoC bearings and 9,323 THAs with MoP bearings were included in the study. To estimate the relative risk (RR) of revision, we used regression with the pseudo-value approach and treated death as a competing risk.Results — 444 revisions were identified: 4.0% for CoC THA (71 of 1,773) and 4.0% for MoP THA (373 of 9,323). No statistically significant difference in the risk of revision for any reason was found for CoC and MoP bearings after 9 years of follow-up (adjusted RR = 1.3, 95% CI: 0.72–2.4). Revision rates due to component failure were 0.5% (n = 8) for CoC bearings and 0.1% (n = 6) for MoP bearings (p < 0.001). 6 patients with CoC bearings (0.34%) underwent revision due to ceramic fracture.Interpretation — When compared to the “standard” MoP bearings, CoC THA had a 33% higher (though not statistically significantly higher) risk of revision for any reason at 9 years.

No functional benefit of larger femoral heads and alternative bearings at 6 months following primary hip replacement

Background and purpose — There has been a recent trend towards the use of greater femoral head sizes in an attempt to improve function and enhance stability after primary hip replacement. This has been associated with the use of alternative bearings, theoretically to reduce wear and improve implant longevity. Methods — We examined the influence of these variables on patient-reported outcome measures (PROMs) for a consecutive series of primary hip replacements using National Joint Registry (NJR) and PROMs-linked data. To minimize the confounding influence of implant design factors, the single most commonly used brand in England and Wales (DePuy Corail Pinnacle) was examined. Improvement in patient hip-specific outcomes (Oxford hip score, OHS), general health outcomes (Euroqol, EQ-5D), and rates of self-reported complications (bleeding, wound problems, re-admission, and reoperation) were compared for different head sizes (28-mm, 32-mm, and 36-mm) and bearings (metal-on-polyethylene (MoP), ceramic-on-polyethylene (CoP), and ceramic-on-ceramic (CoC)), adjusting for differences in case mix. Results — At a mean follow-up of 7 months, improvements in OHS and EQ5D index were similar for 28-mm and 36-mm heads. A 32-mm head was associated with poorer function (OHS: 20, 99% CI: 19–21, p = 0.002; EQ5D index: 0.39, 99% CI: 0.36–0.42, p = 0.004), although these small differences may not be of clinical importance. There were no statistically significant benefits of either CoP or CoC bearings compared to a MoP bearing. Complication rates were similar within comparisons of head sizes or bearings. Interpretation — In this short-term study, we did not find any functional benefits of larger head sizes or alternative bearings, after adjusting for other influences. We question their use in routine primary hip replacement given the lack of evidence of improved long-term survival in the literature.

Fourth-generation ceramic-on-ceramic total hip arthroplasty in patients of 55 years or younger: short-term results and complications analysis.

The incidence of total hip replacement in the younger and more active patients is ever increasing. The ceramic-on-ceramic (COC) bearing was developed to reduce wear debris-induced osteolysis and loosening and to improve the longevity of hip arthroplasties. Few studies have reported the clinical results and complications of the new zirconia-toughened ceramic total hip arthroplasty (THA). A consecutive series of 132 young patients (177 hips) that underwent primary cementless THAs between January 2010 and December 2012 were included in this study. These arthroplasties all had fourth-generation COC bearings performed through a posterolateral approach. The average age was (41.8 ± 8.3) years (ranging from 22 to 55 years), and the mean follow-up period was (24.5 ± 9.4) months (ranging from 12 to 47 months). The results were evaluated both clinically and radiographically. Harris hip score (HHS) was determined before surgery and at the time of each follow-up. Presence of postoperative groin or thigh pain and squeaking were recorded. Other complications such as dislocations, periprosthetic fractures, and ceramic components fractures were diagnosed and treated in emergency. The average HHSs improved from preoperative 60.3 ± 10.7 (ranging from 29 to 76) to 91.0 ± 5.1 (ranging from 74 to 100) at the final follow-up (t = 45.064, P < 0.05), and 97.7% of cases were scored as excellent and good results. At the last follow-up, incidental inguinal pain was found in three hips (1.7%) and thigh pain in 11 hips (6.2%). Radiographs showed a high rate of new bone formation around the acetabular and stem components. No obvious osteolysis or prosthesis loosening was detected. Complications occurred in six hips (3.4%): posterior dislocation in two hips (1.1%), periprosthetic femoral fracture in one hip (0.6%), asymptomatic squeaking in two hips (1.1%), and ceramic liner fracture in one hip (0.6%). The fourth-generation COC THA showed excellent clinical results in younger active patients with no osteolysis-related prosthesis failure at a short-term follow-up study. Surgeons should still be aware of the potential risks of complications such as dislocation, periprosthetic fracture, squeaking, and ceramic components fracture.

Retrieval analysis of alumina ceramic-on-ceramic bearing couples

Background and purpose — Ceramic-on-ceramic (CoC) bearings have been in use in total hip replacement (THR) for more than 40 years, with excellent long-term survivorship. Although there have been several simulator studies describing the performance of these joints, there have only been a few retrieval analyses. The aim of this study was to investigate the wear patterns, the surface properties, and friction and lubrication regimes of explanted first-generation alumina bearings.Materials and methods — We studied 9 explanted CoC bearings from Autophor THRs that were revised for aseptic loosening after a mean of 16 (range 7–19) years. The 3D surface roughness profiles of the femoral heads and acetabular cups (Srms, Sa, and Ssk) were measured to determine the microscopic wear. The bearings were imaged using an atomic-force microscope in contact mode, to produce a topographical map of the surfaces of the femoral heads. Friction tests were performed on the bearing couples to determine the lubrication regime under which they were operating during the walking cycle. The diametral clearances were also measured.Results — 3 femoral heads showed stripe wear and the remaining 6 bearings showed minimal wear. The femoral heads with stripe wear had significantly higher surface roughness than the minimally worn bearings (0.645 vs. 0.289, p = 0.04). High diametral clearances, higher than expected friction, and mixed/boundary lubrication regimes prevailed in these retrieved bearings.Interpretation — Despite the less than ideal tribological factors, these first-generation CoC bearings still showed minimal wear in the long term compared to previous retrieval analyses.

Low aseptic loosening and revision rate in Zweymüller-Plus total hip arthroplasty with ceramic-on-ceramic bearings

A recent comparative study reported lower revision rate and higher survival in ceramic-on-ceramic (CoC) than in metal-on-metal (MoM) coupling in Zweymüller-Plus THA. We retrospectively studied 87 consecutive patients (94 hips), who primarily received Zweymüller-Plus THA (SL-Plus stem, ceramic 28-mm ball head, Bicon cup) with third-generation CoC bearing surfaces for osteoarthritis. Survival, revision and osteolysis rate were studied and compared to those observed in historical series from this institution with the same THA and MoM articulation. The mean ± SD follow-up was 7.4 ± 1.7 years (range 6-10 years). Four hips (4%) in four patients were revised 1-6 years following primary implantation: one (1%) for aseptic loosening of SL-Plus stem and Bicon 5 years after index surgery; one (1%) for malpositioning of the Bicon and recurrent dislocations 1 year following implantation; and two (2%) for septic loosening 1 and 6 years postoperatively. Intraoperatively on inspection, there were neither findings for impingement in the revised hips, nor fracture of the Bicon ceramic inlay and ball head. Expansile osteolysis was shown around SL-Plus stem and Bicon in the revised for aseptic loosening hip. With revision of any component for aseptic loosening as the endpoint, the survival was 99% (95% CI 91-100%), while for revision for any reason, it was 95% (95% CI 87-98%) at 10 years. Zweymüller-Plus THA with CoC bearings showed, at mid-term follow-up, high survival and low revision rate for aseptic loosening. These rates were better than the historical series of the same THA with MoM articulation performed by the same surgeon. Level IV.

Wear Performance of Ceramic-On-Metal Hip Bearings

Ceramic-on-metal (CoM) bearings are considered to be a promising alternative to polyethylene-based bearings or hard-on-hard bearings (Ceramic-on-Ceramic (CoC) and Metal-on-Metal (MoM)). Although, CoM shows lower wear rates than MoM, in-vitro wear testing of CoM shows widely varying results. This may be related to limitations of wear-measuring methods. Therefore, the aim of this study was to improve the gravimetric measurement technique and to test wear behaviour of CoM bearings compared to CoC bearings. Level walking according to ISO-14242 was simulated for four CoM and four CoC bearings. Prior to simulation, errors in measurement of gravimetric wear were detected and improvements in measurement technique incorporated. The results showed no differences in mean wear rates between CoM and CoC bearings. However, the CoM bearings showed wear results over a wide range of wear performance. High reliability of wear results was recorded for the CoC bearings. Material transfer was observed on the ceramic heads of the CoM bearings. Therefore, for level walking a partial mixed or boundary lubrication has to be assumed for this type of bearing. CoM is a highly sensitive wear-couple. The reasons for the observed behaviour cannot be clarified from this study. Simulator studies have to be considered as an ideal loading condition. Therefore, high variations in wear rates as seen in this study, even at low levels, may have an adverse effect on the in-vivo wear behavior. Careful clinical use may be advisable until the reasons for the variation are fully clarified and understood.

Noise characteristics in two types of total hip arthoplasties: A comparative cohort study

The link between squeaking and ceramic on ceramic (CoC) bearings has been widely reported in orthopaedic literature and is described as a hard bearing phenomenon. We aim to look at the incidence of noise in CoC bearings compared to Metal on Polyethylene (MoP) bearing, which have yet to be linked to squeaking. We developed a noise characterizing hip questionnaire and sent that along with the Oxford Hip Score (OHS) to 1000 patients; 3:2 ratio of CoC to MoP. 282 CoC patients and 227 MoP patients returned the questions: 509 patients in total. Our patient database provided details on femoral head size and the acetabular inclination angle, for each respondent 47 (17%) of the CoC hip patients reported noise compared to 19 (8%) of the MoP hip patients (P=0.054). 9 CoC patients and 4 MoP patients reported squeaking, while clicking was the most frequent answer in both groups. 27% patients with noise reported avoiding recreational activities because of it. Patient9s with noisy hips scored on average, 5 points worse in the OHS (CoC: P = 0.04 and MoP: P = 0.007) and were on average 5 years younger (CoC: P The squeaking hip phenomenon is not exclusive to hard bearing THA. Noise from patient9s hips may have social implications and this should be highlighted when consenting a patient for either of these hip procedures. In both implants, we showed there to be a correlation between noise production and a lower OHS. However, longer follow up studies are needed to link noise to a poorly functioning implant

Characterisation of antibody responses to Gal-positive and Gal-free biological heart valves

Characterisation of antibody responses to Gal-positive and Gal-free biological heart valves

New Method Addressing the Problem of Using Ceramic-on-Ceramic Bearing in Too Small Acetabulum of High-Riding DDH Patients with THA

For patients who had Crowe IV dysplastic hips, we try to have THA with ceramic-on-ceramic (CoC) bearing for these patients, but the smallest diameter of the acetabular prosthesis with such bearing is 46 mm, so the question is if we can ream these patients' acetabulum to 44 mm. The purpose of this paper is to confirm the feasibility of this approach in theory and clinically. We use Mimics 10.01 to establish the pelvic finite element models with 37 Crowe IV DDH patients' pelvic CT data, their acetabular sizes were measured, we also make a simulation that implanting the 46 mm acetabular prosthesis in the true acetabulum. Clinically, we have 32 Crowe IV DDH patients (43 hips) between Jan 2007 and Oct 2010, CoC bearings were used for 30 patients (41 hips) and ceramic-on-polyethlene (COP) bearings were used for 2 patients (2 hips) whose height were 130 mm and 132 mm. The mean follow up period was 3.7 years (range, 1.5 to 5.2 years). The average height of these patients' true acetabulum was 36.7 ± 9.3 mm, and the average width was 29.3 ± 8.5 mm. By the simulation, we found it's entirely feasible to implant the 46 mm acetabular prosthesis in the true acetabulum. Clinically, one patient had acetabular fracture but the fracture healed and the biological ingrowth was seen at the final follow-up. The bottom of acetabulum of another patient had been grinded to leakage, but the acetabular prosthesis had enough biological ingrowth at the final follow-up. All cups and stems were stable. No patients required revision at the final follow up. There was no osteolysis, and no dislocation occurred at the final follow-up. We conclude that it's entirely feasible to use the uncemented CoC for Crowe IV DDH patients in theory, and cementless THA with CoC hip bearing for Crowe IV DDH patients can provide a promising early clinical results.

Comparison of Ten-Year Survivorship of Hip Prostheses with Use of Conventional Polyethylene, Metal-on-Metal, or Ceramic-on-Ceramic Bearings

To improve the long-term performance of hip prostheses, alternative bearings with metal-on-metal (MoM) and ceramic-on-ceramic (CoC) couples have been introduced. Although currently the results from the use of these bearings are in the midterm stage, there have been few comparative studies of these different bearings. From 2000 to 2002, 487 total hip replacements were performed with use of a BICON-PLUS acetabular cup and an SL-PLUS femoral stem (Plus Orthopedics, Rotkreuz, Switzerland, now Smith & Nephew Orthopaedics). The patients were divided into three groups according to the type of bearing that was used: an MoM group (sixty-nine prostheses), a metal-on-polyethylene (MoP) group (200 prostheses), and a CoC group (218 prostheses). Patient demographic data and data with regard to revision operations were evaluated from the hospital computer database. The mean follow-up period was 8.5 years (range, 6.9 to 10.5 years). Patient activity was assessed with use of the University of California at Los Angeles activity scale. The mean patient age was sixty years at the time of the index arthroplasty in the MoM and CoC groups, and seventy-one years in the MoP group. Based on a scale of ten, the mean postoperative activity level was six in the CoC group, five in the MoM group, and four in the MoP group. Survival at ten years with regard to revision for any reason was 0.984, 0.956, and 0.879 for the MoP, CoC, and MoM groups, respectively. When revision for any reason was considered as the end point, survival of the MoM bearings was significantly worse than that of the MoP bearings (p = 0.005). Survival at ten years with regard to revision for aseptic loosening was 0.995, 0.990, and 0.894 for the MoP, CoC, and MoM groups, respectively. When revision for aseptic loosening was considered as the end point, survival of the MoM group was significantly worse than that of either the MoP group (p = 0.001) or the CoC group (p = 0.003). When comparing two groups of patients of similar mean age and mean activity level undergoing total hip arthroplasty with the use of alternative bearings, CoC bearings had better survival than did MoM bearings at the ten-year follow-up; the difference was significant when revision for aseptic loosening was defined as a failure. However, neither the CoC nor the MoM alternative bearings provided improved midterm results when compared with the results of the conventional MoP bearings. For older, less active patients, traditional metal-on-polyethylene bearings are the appropriate choice. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Ceramic-Ceramic Bearing: Too Unpredictable to Use it Regularly

Ceramic-on-ceramic (CoC) bearings have excellent tribologic properties because of the smoothness, hardness, and wettability of the material. Therefore, their use has been proposed in younger, active patients who may wear out a traditional metal-on-polyethylene bearing. The same material properties that are beneficial to tribology may also create problems, however. For example, squeaking and fracture of the bearing materials have been reported to occur. The purpose of this paper was to investigate the literature reporting the complications of ceramic bearings and attempt to provide insight into their implications. The US National Library of Medicine Database (PubMed) was searched using the terms "ceramic-ceramic total hip replacement," "complications," "squeaking," and "fracture." Only clinical studies with a clear reporting of the incidence of these complications were included. The literature reports that squeaking of the CoC bearing occurs in a certain percentage of patients and is likely indicative of edge loading and excessive wear. Other factors, such as patient height, weight, range of motion, and implant design, may contribute to the propensity for squeaking. Fracture is a unique risk of the CoC articulation that requires revision surgery. Though improvements in manufacturing techniques have reduced the fracture risk to a very low percentage, the ceramic material remains susceptible to this complication by impingement and component malposition. Because of these possible negative outcomes associated with the ceramic material, the CoC bearing is too unpredictable to use regularly, and its use should be limited to patients who would benefit the most from it.

Advantages and disadvantages of ceramic on ceramic total hip arthroplasty: A review

Ceramic on ceramic (COC) total hip arthroplasty (THA) was developed to reduce wear debris and accordingly, the occurrence of osteolysis and aseptic loosening especially in younger patients. Based on the excellent tribological behavior of current COC bearings and the relatively low biological activity of ceramic particles, significant improvement in survivorship of these implants is expected. We used manual search to identify all relevant studies reporting clinical data on COC THAs in PubMed. The objective was to determine whether current COC THA offers a better clinical outcome and survivorship than non-COC THA. Studies with early generation ceramic bearings yielded 68% to 84% mean survivorship at 20 years follow-up which is comparable with the survivorship of non-COC THAs. Studies on current ceramic bearings report a 10-year revision-free interval of 92% to 99%. These outcomes are comparable to the survivorship of the best non-COC THAs. However, there are still concerns regarding fracture of sandwich ceramic liners, squeaking, and impingement of the femoral neck on the rim of the ceramic liner leading to chipping, especially in younger and physically active patients. Current COC THA leads to equivalent but not improved survivorship at 10 years follow-up in comparison to the best non-COC THA. Based on this review, we recommend that surgeons weigh the potential advantages and disadvantages of current COC THA in comparison to other bearing surfaces when considering young very active patients who are candidates for THA.