Alumina ceramic bearings for total hip arthroplasty

Total hip replacement and surface replacement for the treatment of pain and disability resulting from end-stage arthritis of the hip (review of technology appraisal guidance 2 and 44): systematic review and economic evaluation

BACKGROUND

Total hip replacement (THR) involves the replacement of a damaged hip joint with an artificial hip prosthesis. Resurfacing arthroplasty (RS) involves replacement of the joint surface of the femoral head with a metal surface covering.

OBJECTIVES

To undertake clinical effectiveness and cost-effectiveness analysis of different types of THR and RS for the treatment of pain and disability in people with end-stage arthritis of the hip, in particular to compare the clinical effectiveness and cost-effectiveness of (1) different types of primary THR and RS for people in whom both procedures are suitable and (2) different types of primary THR for people who are not suitable for hip RS.

DATA SOURCES

Electronic databases including MEDLINE, EMBASE, The Cochrane Library, Current Controlled Trials and UK Clinical Research Network (UKCRN) Portfolio Database were searched in December 2012, with searches limited to publications from 2008 and sample sizes of ≥ 100 participants. Reference lists and websites of manufacturers and professional organisations were also screened.

REVIEW METHODS

Systematic reviews of the literature were undertaken to appraise the clinical effectiveness and cost-effectiveness of different types of THR and RS for people with end-stage arthritis of the hip. Included randomised controlled trials (RCTs) and systematic reviews were data extracted and risk of bias and methodological quality were independently assessed by two reviewers using the Cochrane Collaboration risk of bias tool and the Assessment of Multiple Systematic Reviews (AMSTAR) tool. A Markov multistate model was developed for the economic evaluation of the technologies. Sensitivity analyses stratified by sex and controlled for age were carried out to assess the robustness of the results.

RESULTS

A total of 2469 records were screened of which 37 were included, representing 16 RCTs and eight systematic reviews. The mean post-THR Harris Hip Score measured at different follow-up times (from 6 months to 10 years) did not differ between THR groups, including between cross-linked polyethylene and traditional polyethylene cup liners (pooled mean difference 2.29, 95% confidence interval -0.88 to 5.45). Five systematic reviews reported evidence on different types of THR (cemented vs. cementless cup fixation and implant articulation materials) but these reviews were inconclusive. Eleven cost-effectiveness studies were included; four provided relevant cost and utility data for the model. Thirty registry studies were included, with no studies reporting better implant survival for RS than for all types of THR. For all analyses, mean costs for RS were higher than those for THR and mean quality-adjusted life-years (QALYs) were lower. The incremental cost-effectiveness ratio for RS was dominated by THR, that is, THR was cheaper and more effective than RS (for a lifetime horizon in the base-case analysis, the incremental cost of RS was £11,284 and the incremental QALYs were -0.0879). For all age and sex groups RS remained clearly dominated by THR. Cost-effectiveness acceptability curves showed that, for all patients, THR was almost 100% cost-effective at any willingness-to-pay level. There were age and sex differences in the populations with different types of THR and variations in revision rates (from 1.6% to 3.5% at 9 years). For the base-case analysis, for all age and sex groups and a lifetime horizon, mean costs for category E (cemented components with a polyethylene-on-ceramic articulation) were slightly lower and mean QALYs for category E were slightly higher than those for all other THR categories in both deterministic and probabilistic analyses. Hence, category E dominated the other four categories. Sensitivity analysis using an age- and sex-adjusted log-normal model demonstrated that, over a lifetime horizon and at a willingness-to-pay threshold of £20,000 per QALY, categories A and E were equally likely (50%) to be cost-effective.

LIMITATIONS

A large proportion of the included studies were inconclusive because of poor reporting, missing data, inconsistent results and/or great uncertainty in the treatment effect estimates. This warrants cautious interpretation of the findings. The evidence on complications was scarce, which may be because of the absence or rarity of these events or because of under-reporting. The poor reporting meant that it was not possible to explore contextual factors that might have influenced study results and also reduced the applicability of the findings to routine clinical practice in the UK. The scope of the review was limited to evidence published in English in 2008 or later, which could be interpreted as a weakness; however, systematic reviews would provide summary evidence for studies published before 2008.

CONCLUSIONS

Compared with THR, revision rates for RS were higher, mean costs for RS were higher and mean QALYs gained were lower; RS was dominated by THR. Similar results were obtained in the deterministic and probabilistic analyses and for all age and sex groups THR was almost 100% cost-effective at any willingness-to-pay level. Revision rates for all types of THR were low. Category A THR (cemented components with a polyethylene-on-metal articulation) was more cost-effective for older age groups. However, across all age-sex groups combined, the mean cost for category E THR (cemented components with a polyethylene-on-ceramic articulation) was slightly lower and the mean QALYs gained were slightly higher. Category E therefore dominated the other four categories. Certain types of THR appeared to confer some benefit, including larger femoral head sizes, use of a cemented cup, use of a cross-linked polyethylene cup liner and a ceramic-on-ceramic as opposed to a metal-on-polyethylene articulation. Further RCTs with long-term follow-up are needed.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42013003924.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Comparison of ceramic-on-ceramic to metal-on-polyethylene bearing surfaces in total hip arthroplasty: a meta-analysis of randomized controlled trials

Background

In recent years, the choice of ceramic-on-ceramic (COC) and metal-on-polyethylene (MOP) in primary total hip arthroplasty (THA) remains controversial. The purpose of this study was to compare the reliability and durability of COC with that of MOP bearing surfaces in THA.

Methods

Based on prospective randomized controlled trials (RCTs) searched from Pubmed, Embase, Web of Science, and Cochrane central database, we performed a meta-analysis for comparing clinical and radiographic outcomes of COC with those of MOP. Two investigators independently selected studies, extracted data, and assessed risk of bias. Relative risks and weighted mean differences from each trial were pooled using random-effect or fixed-effect models depending on the heterogeneity of the included studies.

Results

Five RCTs involving 897 patients with 974 hips met predetermined inclusion criteria. Our results demonstrated COC significantly decreased the risks of revision, osteolysis and radiolucent line, aseptic loosening, and dislocation and increased the risks of squeaking and intraoperative implant fracture compared with MOP. There was no significant difference between the two groups in postoperative hip function, deep infection, and heterotopic ossification.

Conclusions

Generally, despite more squeaking and intraoperative implant fracture, our findings support the use of COC bearing surface which has lower rates of revision, osteolysis and radiolucent line, aseptic loosening, and dislocation compared with MOP.

Total hip replacement for the treatment of end stage arthritis of the hip: a systematic review and meta-analysis

Background

Evolvements in the design, fixation methods, size, and bearing surface of implants for total hip replacement (THR) have led to a variety of options for healthcare professionals to consider. The need to determine the most optimal combinations of THR implant is warranted. This systematic review evaluated the clinical effectiveness of different types of THR used for the treatment of end stage arthritis of the hip.

Methods

A comprehensive literature search was undertaken in major health databases. Randomised controlled trials (RCTs) and systematic reviews published from 2008 onwards comparing different types of primary THR in patients with end stage arthritis of the hip were included.

Results

Fourteen RCTs and five systematic reviews were included. Patients experienced significant post-THR improvements in Harris Hip scores, but this did not differ between impact types. There was a reduced risk of implant dislocation after receiving a larger femoral head size (36 mm vs. 28 mm; RR = 0.17, 95% CI: 0.04, 0.78) or cemented cup (vs. cementless cup; pooled odds ratio: 0.34, 95% CI: 0.13, 0.89). Recipients of cross-linked vs. conventional polyethylene cup liners experienced reduced femoral head penetration and revision. There was no impact of femoral stem fixation and cup shell design on implant survival rates. Evidence on mortality and complications (aseptic loosening, femoral fracture) was inconclusive.

Conclusions

The majority of evidence was inconclusive due to poor reporting, missing data, or uncertainty in treatment estimates. The findings warrant cautious interpretation given the risk of bias (blinding, attrition), methodological limitations (small sample size, low event counts, short follow-up), and poor reporting. Long-term pragmatic RCTs are needed to allow for more definitive conclusions. Authors are encouraged to specify the minimal clinically important difference and power calculation for their primary outcome(s) as well CONSORT, PRISMA and STROBE guidelines to ensure better reporting and more reliable production and assessment of evidence.

Implants for total hip arthroplasty

This article is a comprehensive review of the published literature on total hip replacement design. It seeks to provide a nonbiased view of the technology related to total hip implants and bearing surfaces. Implant designs and fixation methods are discussed with summaries of their respective long-term outcome studies. Fixation methods include cemented, cementless and hybrid techniques and are explained and presented with current outcome data and their respective failure modes that have promoted new technological development. The current data point toward cementless acetabular fixation as being superior to cemented fixation. As for stem fixation, there are good data to suggest that either method of fixation is acceptable in the proper setting. Also included in this article is a brief review of bearing surfaces and hip biomechanics.

Fracture of the alumina-bearing couple delta ceramic liner

The fracture rate of third-generation ceramic liners is greatly reduced compared with first- and second-generation liners because of improvements in the design and manufacturing process. Fractures of the alumina-bearing couple are rare for the same reason.This article describes a case of a fracture of an alumina-bearing couple delta ceramic liner without trauma history that was treated with ceramic-on-polyethylene revision total hip arthroplasty. A 57-year-old man was admitted to the hip ward because of an alumina-bearing couple delta ceramic liner fracture. He underwent hip replacement by anterior approach 18 months previously in the same center because of left hip primary osteoarthritis. He received a 54×36-mm modular press-fit cup ceramic alumina-bearing couple delta insert. Probable causes of such fractures are manufacture production failure and edge loading based on cup inclination, but in our patient, inacceptable range of motion, failure of the locking mechanism during implantation insertion, or cracking were possible causes of fracture.Although the fracture rate of third-generation alumina-bearing couples is low, we believe that it may not be possible to eliminate the actual risk of alumina head fracture. Patients should be informed about the potential for this complication before receiving an alumina-bearing couple.

Comparison of surgical outcomes and implant wear between ceramic-ceramic and ceramic-polyethylene articulations in total hip arthroplasty

The results of a prospective multicenter trial comparing 357 hips randomized to total hip arthroplasty with either ceramic-ceramic or ceramic-polyethylene couplings are presented. No statistically significant difference in clinical outcomes scores between the ceramic-ceramic and ceramic-polyethylene groups was observed at any time interval. The mean linear rate was statistically lower (P < .001) in the ceramic-ceramic group (30.5 μm/year) when compared with the ceramic-polyethylene group (218.2 μm/year). The rates of ceramic implant fracture (2.6%) and audible component-related noise (3.1%) were statistically higher in the ceramic-ceramic group when compared with the ceramic-polyethylene group (P < .05). Lastly, there was no statistically significant difference in the dislocation or revision rate between the groups at the time of last clinical follow-up.

Ceramic-on-ceramic hip outcome at a 5- to 10-year interval: has it lived up to its expectations?

This study reports revision and complication rates of a single cementless double-wedged tapered stem with an alumina-alumina bearing over 10 years since the beginning of premarket clinical trials. Of 930 hips (848 patients) implanted by 9 surgeons, there were 19 revisions at mean follow-up of 5.9 years compared to 10 revisions in the 123 hips implanted with the polyethylene control group at mean 7.8 years. The ongoing safety of alumina-alumina bearings is demonstrated through excellent (96.8%) survivorship at 10 years. Twenty-one patients reported 23 incidences of noise described as clicking, squeaking, popping, or creaking. Eight patients with 9 hips described the noise as squeaking, most occurring rarely and only 1 occurring frequently in a patient subsequently revised for a reason aside from the squeaking.

Hospital economics of primary THA decreasing reimbursement and increasing cost, 1990 to 2008

BACKGROUND

The introduction of new technology has increased the hospital cost of THA. Considering the impending epidemic of hip osteoarthritis in the United States, the projections of THA prevalence, and national cost-containment initiatives, we are concerned about the decreasing economic feasibility of hospitals providing THA.

QUESTIONS/PURPOSES

We compared the hospital cost, reimbursement, and profit/loss of THA over the 1990 to 2008 time period.

METHODS

We reviewed the hospital accounting records of 104 patients in 1990 and 269 patients in 2008 who underwent a unilateral primary THA. Hospital revenue, hospital expenses, and hospital profit (loss) for THA were evaluated and compared in 1990, 1995, and 2008.

RESULTS

From 1990 to 2008, hospital payment for primary THA increased 29% in actual dollars, whereas inflation increased 58%. Lahey Clinic converted a $3848 loss per case on Medicare fee for service, primary THA in 1990 to a $2486 profit per case in 1995 to a $2359 profit per case in 2008. This improvement was associated with a decrease in inflation-adjusted revenue from 1995 to 2008 and implementation of cost control programs that reduced hospital expenses. Reduction of length of stay and implant costs were the most important drivers of expense reduction. In addition, the managed Medicare patient subgroup reported a per case profit of only $650 in 2008.

CONCLUSIONS

If hospital revenue for THA decreases to managed Medicare levels, it will be difficult to make a profit on THA. The use of technologic enhancements for THA add to the cost problem in this era of healthcare reform. Hospitals and surgeons should collaborate to deliver THA at a profit so it will be available to all patients. Government healthcare administrators and health insurance payers should provide adequate reimbursement for hospitals and surgeons to continue delivery of high-quality THAs.

LEVEL OF EVIDENCE

Level III, economic and decision analysis. See Guidelines for Authors for a complete description of levels of evidence.

Nine years follow-up of 100 ceramic-on-ceramic total hip arthroplasty

The aim of this study was to evaluate the first 100 cementless ceramic-on-ceramic total hip arthroplasty (THA) performed at our institution with more than nine years of follow-up. Clinical evaluation was performed using Harris hip score. Radiological evaluation was performed by two surgeons. Four patients were lost to follow-up. Harris hip score significantly improved at latest follow-up. Radiological analysis showed calcar osteolysis for 75 patients and one cup loosening. One patient required a revision five years postoperatively for cup loosening. Based on these results and the routine use of a navigation system to optimise positioning of the implants, we advocate the use of uncemented hydroxyapatite coated ceramic-on-ceramic THA in young and active patients in our current practice.

Two- to 9-year clinical results of alumina ceramic-on-ceramic THA

From June 1997 to June 2003 we performed 194 total hip arthroplasties on 173 patients using alumina ceramic-on-ceramic bearings as part of a prospective United States Food and Drug Administration/Investigational Device Exemption study. The average patient age at surgery was 49.9 years. Minimum followup time was 2 years (mean 4.3 years, range 2-9 years). We evaluated survival rate, implant- and nonimplant-related complications. Clinical outcomes included the Merle d'Aubigné score. We assessed radiographs for signs of osteolysis, component loosening, and implant wear. No patients had osteolysis and there were no hip dislocations. Implant survivorship for all hips with aseptic revision of any component was 96% (CI, 91-100) at 9 year; survivorship for hips without prior surgery was 99.3%, (CI, 98-100). There was a 1.7% incidence of implant-related complications. Our data help confirm two United States FDA/IDE studies on alumina ceramic-on-ceramic total hip arthroplasty that reported low aseptic revision rates and low revision rates for instability. Total hip arthroplasty using alumina ceramic-on-ceramic implants is a safe and reliable procedure in the comparably young and active patient.

The S-ROM stem and its use with alternative bearings

Many long-term studies of total hip arthroplasty (THA) show excellent results. This long-term success depends on many factors, including implant fixation and bearing surface wear. As THA is commonly performed on patients with a steadily increasing life span and activity level, the issue of wear has become critical. Advances in the wear properties of polyethylene have been significant, but, in the search for low long-term wear rates, hard bearing surfaces are frequently used.

Low temperature formation of hydroxyapatite-poly(alkyl oxybenzoate)phosphazene composites for biomedical applications

The formation of biodegradable composites which may be suitable as bone analogs is described. Polyphosphazene-hydroxyapatite (HAp) composites were produced via an acid-base reaction of tetracalcium phosphate and anhydrous dicalcium phosphate in the presence of polyphosphazenes bearing alkyl ester containing side-groups. The polyphosphazenes used were poly(ethyl oxybenzoate)phosphazene (PN-EOB) and poly(propyl oxybenzoate) phosphazene (PN-POB). The effects of temperature and the proportions of polymers, PN-EOB and PN-POB on the kinetics, reaction chemistry and phase evolution during the formation of stoichiometric HAp were studied. Kinetics, phase evolution and microstructural development were evaluated using isothermal calorimetry, X-ray diffraction and scanning electron microscopy, respectively. Analysis of solution chemistry revealed that the increases in the pH during the formation of SHAp, resulted in partial hydrolysis of the polymer surfaces, which led in turn to the formation of a calcium cross-linked polymer surface. The calcium cross-linked polymer surface appeared to facilitate the nucleation and growth of apatite deposits on the polymer. The current study illustrates the in situ formation of HAp in the presence of polyphosphazenes, where HAp is chemically bonded to the polymer.