Do the potential benefits of metal-on-metal hip resurfacing justify the increased cost and risk of complications?

Outcome measures in total hip arthroplasty: have our metrics changed over 15 years?

INTRODUCTION

Consensus has not been reached regarding ideal outcome measures for total hip arthroplasty (THA) clinical evaluation and research. The goal of this review was to analyze the trends in outcome metrics within the THA literature and to discuss the potential impact of instrument heterogeneity on clinical practice.

MATERIALS AND METHODS

A PubMed search of all manuscripts related to THA from January 2005 to December 2019 was performed. Statistical and linear regression analyses were performed for individual outcome metrics as a proportion of total THA publications over time.

RESULTS

There was a statistically significant increase in studies utilizing outcomes metrics between 2005 and 2019 (15.1-29.5%; P < 0.001; R² = 98.1%). Within the joint-specific subcategory, use of the Harris Hip Score (HHS) significantly decreased from 2005 to 2019 (82.8-57.3%; P < 0.001), use of the Hip Disability and Osteoarthritis Outcome Score (HOOS) significantly increased (0-6.7%; P < 0.001), and the modified HHS significantly increased (0-10.5%; P < 0.001). In the quality of life subcategory, EQ-5D demonstrated a significant increase in usage (0-34.8%; P < 0.001), while Short Form-36 significantly decreased (100% vs. 27.3%; P = 0.008).

CONCLUSIONS

The utilization of outcome-reporting metrics in THA has continued to increase, resulting in added complexity within the literature. The utilization rates of individual instruments have shifted over the past 15 years. Additional study is required to determine which specific instruments are recommended.

Cost effectiveness analyses of total hip arthroplasty for hip osteoarthritis: A PRISMA systematic review

BACKGROUND

Healthcare services are facing economic constraints globally with an increasingly elderly population, and greater burdens of osteoarthritis. Because of the chronic nature of osteoarthritis and the costs associated with surgery, arthroplasty is seen as potentially cost saving. There have been no systematic reviews conducted on cost effectiveness analysis (CEA) studies of total hip arthroplasty (THA) in the management of osteoarthritis. The aim of this systematic review was to evaluate CEAs conducted on THA for osteoarthritis to determine if THA is a cost-effective intervention.

MATERIALS AND METHODS

A systematic review was conducted using five databases to identify all clinical CEAs of THA for osteoarthritis conducted after 1 January 1997. Twenty-eight studies were identified that met the inclusion criteria. The Quality of Health Economic Analysis (QHES) checklist was employed to assess the quality of the studies.

RESULTS

The average QHES score was 86 indicating high quality studies. All studies reviewed concluded that THA was a cost-effective intervention. In younger patients, cementless THA and ceramic on polyethylene implants were found to be most cost effective. Hybrid THA and metal on polyethylene implants had the greatest cost utility in older patients. In patients with acetabular defects, cemented cup with impaction bone grafting was most cost effective, while dual mobility THA was most cost effective in patients with high risk of dislocation.

CONCLUSION

We have shown that THA is a cost-effective treatment for hip osteoarthritis. These findings should be implemented into clinical practice to improve cost utility in health services across the world.

Benefits and Adverse Events Associated With Extended Antibiotic Use in Total Knee Arthroplasty Periprosthetic Joint Infection

BACKGROUND

Total knee arthroplasty (TKA) periprosthetic joint infection (PJI) can be managed with debridement, antibiotic therapy, and implant retention (DAIR). Oral antibiotics can be used after DAIR for an extended time period to improve outcomes. The objective of this study was to compare DAIR failure rates and adverse events between an initial course of intravenous antibiotic therapy and the addition of extended treatment with oral antibiotics.

METHODS

A multicenter observational study of patients diagnosed with a TKA PJI who underwent DAIR was performed. The primary outcome of interest was the failure rate derived from the survival time between the DAIR procedure and future treatment failure.

RESULTS

One hundred eight patients met inclusion criteria; 47% (n = 51) received an extended course of oral antibiotics. These patients had a statistically significant lower failure rate compared to those who received only intravenous antibiotics (hazard ratio, 2.47; P = .009). Multivariable analysis demonstrated that extended antibiotics independently predicted treatment success, controlling for other variables. There was no significant difference in failure rates between an extended course of oral antibiotics less or more than 12 months (P = .23). No significant difference in the rates of adverse events was observed between patients who received an initial course of antibiotics alone and those who received a combination of initial and extended antibiotic therapy (P = .59).

CONCLUSIONS

Extending therapy with oral antibiotics had superior infection-free survival for TKA PJI managed with DAIR. There was no increase in adverse events, demonstrating safety. After 1 year, there appears to be no significant benefit associated with continued antibiotic therapy.

Is the economic and social cost of one-stage bilateral hip resurfacing lower than two-stage procedures? Retrospective case-control study of 260 hips

BACKGROUND

Studies on the economic impact of medical practices and estimates of intra- and extra-hospital costs have an important role in controlling healthcare spending. But few studies of this nature have been done for bilateral surgery in a single operative session. This led us to carry out a health economics study to determine whether (1) bilateral hip resurfacing arthroplasty (HRA) performed in one stage instead of two stages will reduce the health care expenditures (costs of hospitalization, medical leave, rehabilitation), (2) it is equally safe for the patient. Hypothesis One-stage bilateral HRA is less costly for the health care system than two-stage bilateral resurfacing.

METHODS

This was a single-center, single-surgeon retrospective cohort study comparing patients who underwent bilateral HRA in one stage (53 cases) or in two stages (77 cases). We determined the intra-hospital costs based on the French National Cost Scales and the extra-hospital costs (medical leave and rehabilitation), perioperative data (blood loss, operation time, duration of narcotic analgesic use, medical and surgical complications) and the outcomes with a mean follow-up of 4.8 years [1.7-10.1].

RESULTS

The total costs for the one-stage group (€16,840.94±7042.7) were significantly less than those of the two-stage group (€19,335.0±7296.9) (p=0.0101). The two groups were comparable except for the one-stage group having more primary hip osteoarthritis indications (72% (38/53)) than the two-stage group (49% (38/77)) (p=0.0111). The main differences between groups was the cost and duration of hospitalization, with cost of €10,546.06±2049.47 and average length of stay (ALS) of 9.83±2.19 days in the one-stage group and €13,569.49±2186.30, ALS=15.04±3.15 days in the two-stage group (p<0.0001). There was no significant difference in the length of medical leave: 67.15±50.36 (0-180) days for the one-stage group and 97.89±108.39 (0-730) days for the two-stage group (p=0.1933).

CONCLUSION

Performing bilateral HRA during a single hospital stay results in lower health care expenditures than performing it during two separate hospital stays. Similar studies on other surgical procedures could help to promote the simultaneous nature of bilateral procedures and reset the current pricing, which is currently too low in the French health care system.

LEVEL OF EVIDENCE

III, Retrospective case-control study.

EQ-5D-5L utilities per health states in Spanish population with knee or hip osteoarthritis

BACKGROUND

The objective of this study was to obtain utilities by means of EQ-5D-5L for different health states in patients with knee osteoarthritis (KOA) or hip osteoarthritis (HOA) in Spain, and to compare these values with those used in foreign studies with the aim of discussing their transferability for their use in economic evaluations conducted in Spain.

METHODS

Primary study: Observational prospective study of KOA or HOA patients in Spain. Sociodemographic and clinical characteristics were collected to characterize the sample. Utilities were elicited using the EQ-5D-5L questionnaire. ANOVA and bivariable analyses were conducted to identify differences between health states.

LITERATURE REVIEW

Using the bibliographic databases NSH EED and CEA Registry, we conducted searches of model-based cost utilities analyses of technologies in KOA or HOA patients. Health states and utilities were extracted and compared with values obtained from the Spanish sample.

RESULTS

Three hundred ninety-seven subjects with KOA and 361 subjects with HOA were included, with average utilities of 0.544 and 0.520, respectively. In both samples, differences were found in utilities according to level of pain, stiffness and physical function (WOMAC) and severity of symptoms (Oxford scales), so that the worst the symptoms, the lower the utilities. The utilities after surgery were higher than before surgery. Due to limitations from our study related to sample size and observational design, it was not possible to estimate utilities for approximately half the health states included in the published models because they were directly related to specific technologies. For almost 100% of health states of the selected studies we obtained very different utilities from those reported in the literature.

CONCLUSIONS

To our knowledge this is the first article with detailed utilities estimated using the EQ-5D-5L in Spain for KOA and HOA patients. In both populations, utilities are lower for worse health states in terms of level of pain, stiffness and physical function according to WOMAC, and according to the Oxford scales. Most utilities obtained from the Spanish sample are lower than those reported in the international literature. Further studies estimating utilities from local populations are required to avoid the use of foreign sources in economic evaluations.

Choice of Prosthetic Implant Combinations in Total Hip Replacement: Cost-Effectiveness Analysis Using UK and Swedish Hip Joint Registries Data

BACKGROUND

Prosthetic implants used in total hip replacements (THR) have a range of bearing surface combinations (metal-on-polyethylene, ceramic-on-polyethylene, ceramic-on-ceramic, and metal-on-metal), head sizes (small [<36 mm in diameter] and large [≥36 mm in diameter]), and fixation techniques (cemented, uncemented, hybrid, and reverse hybrid). These can influence prosthesis survival, patients' quality of life, and healthcare costs.

OBJECTIVES

To compare the lifetime cost-effectiveness of implants for patients of different age and sex profiles.

METHODS

We developed a Markov model to compare the cost-effectiveness of various implants against small-head cemented metal-on-polyethylene implants. The probability that patients required 1 or more revision surgeries was estimated from analyses of more than 1 million patients in the UK and Swedish hip joint registries, for men and women younger than 55, 55 to 64, 65 to 74, 75 to 84, and 85 years and older. Implant and healthcare costs were estimated from local procurement prices, national tariffs, and the literature. Quality-adjusted life-years were calculated using published utility estimates for patients undergoing THR in the United Kingdom.

RESULTS

Small-head cemented metal-on-polyethylene implants were the most cost-effective for men and women older than 65 years. These findings were robust to sensitivity analyses. Small-head cemented ceramic-on-polyethylene implants were most cost-effective in men and women younger than 65 years, but these results were more uncertain.

CONCLUSIONS

The older the patient group, the more likely that the cheapest implants, small-head cemented metal-on-polyethylene implants, were cost-effective. We found no evidence that uncemented, hybrid, or reverse hybrid implants were the most cost-effective option for any patient group. Our findings can influence clinical practice and procurement decisions for healthcare payers worldwide.

Cost-effectiveness of surgical interventions for the management of osteoarthritis: a systematic review of the literature

Background

The primary purpose of this study is to assess the existing evidence on the cost-effectiveness of surgical interventions for the management of knee and hip osteoarthritis by systematically reviewing published economic evaluation studies.

Methods

A systematic review was conducted for the period 2004 to 2016. Electronic databases were searched to identify both trial and model based economic evaluation studies that evaluated surgical interventions for knee and hip osteoarthritis.

Results

A total of 23 studies met the inclusion criteria and an assessment of these studies showed that total knee arthroplasty (TKA), and total hip arthroplasty (THA) showed evidence of cost-effectiveness and improvement in quality of life of the patients when compared to non-operative and non-surgical procedures. On the other hand, even though delaying TKA and THA may lead to some cost savings in the short-run, the results from the study showed that this was not a cost-effective option.

Conclusions

TKA and THA are cost-effective and should be recommended for the management of patients with end stage/severe knee and hip OA. However, there needs to be additional studies to assess the cost-effectiveness of other surgical interventions in order for definite conclusions to be reached.

Electronic supplementary material

The online version of this article (doi:10.1186/s12891-017-1540-2) contains supplementary material, which is available to authorized users.

Conflicts of Interest in Medical Technology Markets: Evidence from Orthopedic Surgery

Financial relationships between physicians and industry are vital to biomedical innovation yet create the potential for conflicts of interest in medical practice. I consider an inducement model of the role of financial relationships in health care markets, where consulting payments induce physicians to use more devices of the firms that sponsor them. To test the model, I exploit a policy shock, whereby government monitoring of payments to joint replacement surgeons resulted in declines of over 60% in both total payments and in the number of physicians receiving payments from 2007 to 2008. Using hospital discharge data from three states, I find that the loss of payments leads physicians to switch 7 percentage points of their device utilization from their sponsoring firms' devices to other firms' devices, an effect which is concentrated among surgeons with low switching costs. These results offer support for the inducement model. I also find evidence of an increase in medical productivity following the policy intervention, which suggests conditions under which regulation of financial relationships would be socially beneficial. Copyright © 2015 John Wiley & Sons, Ltd.

Otto Aufranc Award: Large Heads Do Not Increase Damage at the Head-neck Taper of Metal-on-polyethylene Total Hip Arthroplasties

BACKGROUND

Fretting and corrosion at head-neck junctions of total hip arthroplasties (THAs) have been associated with adverse local tissue reactions in patients with both metal-on-polyethylene (MoP) and metal-on-metal (MoM) prostheses. Femoral head size contributes to the severity of fretting and corrosion in large-diameter MoM THAs, but its impact on such damage in MoP THAs remains unknown.

QUESTIONS/PURPOSES

(1) Is femoral head size associated with increased fretting or corrosion at the head-neck junction in MoP total hips? (2) Is duration of implantation associated with increased fretting or corrosion?

METHODS

The severity of fretting/corrosion on surfaces of head tapers and stem trunnions was visually examined in 154 MoP THAs retrieved as part of 3282 revision surgeries performed at our institution between January 1, 2007, and December 31, 2013. Fretting and corrosion damage were subjectively graded by two independent observers on a 1 to 4 scale, and their relations to head size, alloy combinations, taper/trunnion design, length of implantation (LOI), and location were investigated. Differences in scores never exceeded one grade, and this occurred in only 17% of examined implants. With the available implants, the study provided 88% power to detect differences of 0.5 in fretting or corrosion scores in these analyses.

RESULTS

Fretting and corrosion of the tapers and the trunnions were not affected by head size (p = 0.247, p = 0.471, p = 0.837, and p = 0.868, respectively), although taper/trunnion design affected taper fretting (p = 0.005) and corrosion (p = 0.0031) and trunnion fretting (p = 0.0028). Head taper fretting (observed in 73% of heads) increased with LOI, but head taper corrosion (noted in 93% of heads) was not affected. Trunnion fretting (observed in 86% of stems) was more severe in mixed-alloy combinations and with increased LOI and was more severe proximally. Trunnion corrosion (noted in 72% of stems) was also location-dependent with greater corrosion distally.

CONCLUSIONS

Fretting and corrosion are regular occurrences in MoP THAs, but neither damage type was related to femoral head size. Conversely, taper design, LOI, and alloy combination affected the severity of both fretting and corrosion.

CLINICAL RELEVANCE

Although it has been suggested that trunnion corrosion seen in MoP bearings is a function of larger diameter heads, our data suggest that larger femoral heads may be used for increased damage at the modular junction of MoP THAs.

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.

Direct Costs of Aspirin versus Warfarin for Venous Thromboembolism Prophylaxis after Total Knee or Hip Arthroplasty

Interest in aspirin as an alternative strategy for venous thromboembolism prophylaxis after arthroplasty has grown, as studies have suggested improved clinical efficacy and lower complication rates with aspirin compared to warfarin. The goal of this study was to compare the direct costs of an episode of arthroplasty care, when using aspirin instead of warfarin. The charts of patients who either received aspirin or warfarin after arthroplasty from January 2008 to March 2010 were retrospectively reviewed. Charges were recorded for their index admission, and for subsequent admissions related to either VTE or complications of prophylaxis. Multivariate analysis revealed that aspirin was an independent predictor of decreased cost of index hospitalization, and total episode of care charges, achieved largely through a shorter length of hospitalization.

Diagnosis, prevention, and management of canine hip dysplasia: a review

Canine hip dysplasia (CHD) is a polygenic and multifactorial developmental disorder characterized by coxofemoral (hip) joint laxity, degeneration, and osteoarthritis (OA). Current diagnostic techniques are largely subjective measures of joint conformation performed at different stages of development. Recently, measures on three-dimensional images generated from computed tomography scans predicted the development of OA associated with CHD. Continued refinement of similar imaging methods may improve diagnostic imaging techniques to identify dogs predisposed to degenerative hip joint changes. By current consensus, joint changes consistent with CHD are influenced by genetic predisposition as well as environmental and biomechanical factors; however, despite decades of work, the relative contributions of each to the development and extent of CHD signs remain elusive. Similarly, despite considerable effort to decipher the genetic underpinnings of CHD for selective breeding programs, relevant genetic loci remain equivocal. As such, prevention of CHD within domestic canine populations is marginally successful. Conservative management is often employed to manage signs of CHD, with lifelong maintenance of body mass as one of the most promising methods. Surgical intervention is often employed to prevent joint changes or restore joint function, but there are no gold standards for either goal. To date, all CHD phenotypes are considered as a single entity in spite of recognized differences in expression and response to environmental conditions and treatment. Identification of distinct CHD phenotypes and targeting evidence-based conservative and invasive treatments for each may significantly advance prevention and management of a prevalent, debilitating condition in canine companions.

Current status of cost utility analyses in total joint arthroplasty: a systematic review

BACKGROUND

Total joint arthroplasty (TJA), although considered to be highly beneficial, is associated with substantial costs to the US healthcare system. Cost utility analysis has become an increasingly important means to objectively evaluate the value of a healthcare intervention from the perspective of both extending the quantity and improving the quality of life. Relatively little is known about the overall cost utility analysis evidence base in TJA.

QUESTIONS/PURPOSES

The goals of this review were to (1) determine the cost utility of TJA interventions; (2) critically assess the quality of published US-based cost utility analyses using the Quality of Health Economic Studies instrument; and (3) determine what characteristics were common among studies receiving a high quality score.

METHODS

A systematic review of the literature using the MEDLINE database was performed to compile findings and critically appraise US-based cost utility analysis studies for total hip and knee arthroplasty. Based on review of 676 identified articles, 23 studies were included. We used the Quality of Health Economic Studies instrument to assess study quality and one-sided Fisher's exact tests were applied to analyze the predictors of high-quality cost utility analysis.

RESULTS

Very few studies compare the cost utility of TJA versus nonoperative intervention; however, the available evidence suggests that TJA can be cost-saving and is highly cost-effective compared with conservative management of end-stage arthritis. The majority of identified studies are focused on the cost utility of new implant technologies or comparisons among surgical alternatives. These studies suggest that the upfront costs associated with new technologies are cost-effective when there is a major reduction in a future cost. The quality of identified studies is quite high (Quality of Health Economic Studies Instrument score: mean 86.5; range, 63-100). National funding source (p = 0.095) and lifetime horizon for analysis (p = 0.07) correlate with high-quality evidence but do not reach significance.

CONCLUSIONS

Over the past 15 years, there has been a major increase in the volume of cost utility analyses published in total hip and knee arthroplasty. The quality of cost utility analyses published during that period is good. As increasing attention is paid to value in US health care, more attention should be paid to understanding the cost utility of TJA compared with nonoperative treatment modalities. Future studies may also look to incorporate patient willingness to pay.

Hip resurfacing arthroplasty: mid-term results in 486 cases and current indication in our institution

In the previous decade, metal-on-metal hip resurfacing has been considered an attractive option and theoretically advantageous over conventional total hip arthroplasty, especially in young active patients. Different authors have reported favourable mid-term clinical and functional results with acceptable survival rates. Proper indication and planning, as accurate technical execution have been advocated to be crucial elements for success.Concerns regarding serum metal ion levels and possible clinical implications have led in the last years to a decline in the use of metal-on-metal hip resurfacing and metal-on-metal bearings in general.The aim of this study is to present the results of our first 486 cases of hybrid hip resurfacing arthroplasties with a second generation cementing technique, and to describe our current restricted indication of this type of prosthesis, in the light of recent findings in the literature about the possible complications related to metallosis or improper patient selection. Global survivorship of our series was 97.9% at a mean follow-up of 7.2 years.In the second season of our experience the indication is restrictive. The candidate for a resurfacing hip replacement is a young and active male patient, with good bone quality, that has been made aware of the risks and benefits of this type of prosthesis.

Cost-utility of metal-on-metal hip resurfacing compared to conventional total hip replacement in young active patients with osteoarthritis

BACKGROUND

Metal-on-metal hip resurfacing arthroplasty (MoM HRA) has emerged as an alternative to total hip arthroplasty (THA) for younger active patients with osteoarthritis (OA). Birmingham hip resurfacing is the most common MoM HRA in Alberta, and is therefore compared with conventional THA.

OBJECTIVE

The objective of this study was to estimate the expected cost-utility of MoM HRA versus THA, in younger patients with OA, using a decision analytic model with a 15-year time horizon.

METHODS

A probabilistic Markov decision analytic model was constructed to estimate the expected cost per quality-adjusted life-year (QALY) of MoM HRA versus THA from a health care payer perspective. The base case considered patients with OA aged 50 years; men comprised 65.9% of the cohort. Sensitivity analyses evaluated cohort age, utility values, failure probabilities, and treatment costs. Data were derived from the Hip Improvement Project and the Hip and Knee Replacement Pilot databases in Alberta, the 2010 National Joint Replacement Registry of the Australian Orthopaedic Association, and the literature.

RESULTS

In the base case, THA was dominated by MoM HRA (incremental mean costs of -$583 and incremental mean QALYs of 0.079). In subgroup analyses, THA remained dominated when cohort age was 40 years instead of 50 years or when only men were assessed. THA dominated when the cohort age was 60 years or when only women were assessed. Results were sensitive to utilities, surgery costs, and MoM HRA revision and conversion probabilities. At a willingness-to-pay of Can $50,000/QALY, there was a 58% probability that MoM HRA is cost-effective.

CONCLUSIONS

The results show that, on average, MoM HRA was preferred to THA for younger and male patients, but THA is still a reasonable option if the patient or clinician prefers given the small absolute differences between the options and the confidence ellipses around the cost-effectiveness estimates.

The cost-effectiveness of total joint arthroplasty: a systematic review of published literature

OBJECTIVE

To summarise the state of the literature evaluating the cost-effectiveness of elective total hip and knee arthroplasty (THA and TKA).

METHODS

We conducted a systematic review of published cost-effectiveness analyses of THA and TKA. To limit our search to high-quality published papers, we selected those papers included in the Cost-Effectiveness Analysis Registry (created by the Center for the Evaluation of Value and Risk in Health at Tufts University) and augmented the search with papers listed in PubMed. The data abstracted included incremental cost-effectiveness ratios, perspective of the analysis, time frame, sensitivity analyses conducted, and utility assessment. All cost-effectiveness ratios were converted to 2011 USD.

RESULTS

Seven studies presenting cost-effectiveness ratios for TKA and six studies for THA were included in our review. All economic evaluations of TKA were published between 2006 and 2012. By contrast, THA studies were published between 1996 and 2008. Out of the 13 studies evaluated in this review, four were from the societal perspective and eight were from the payer perspective. Five studies spanned the lifetime horizon. Of the selected studies, six used probabilistic sensitivity analysis to address uncertainty in data parameters. Both procedures have been shown to be highly cost-effective from the societal perspective over the entire lifespan.

CONCLUSION

THA and TKA have been found to be highly cost-effective in a number of high-quality studies. Further analyses are needed on the cost-effectiveness of alternative surgical options, particularly osteotomy. Future economic evaluations should address the expanding indications of THA and TKA to younger, more physically active individuals.

Successful fixation of an intertrochanteric fracture after hip resurfacing arthroplasty using cannulated screws

We report a case of successful treatment of a high, stable intertrochanteric fracture (type 1) in a 59-year-old man. He sustained the injury 8 years after the resurfacing procedure. The fracture was fixed using three 6.5-mm cannulated screws, and he has returned to his normal level of activities 8 months after the fixation. We have shown that fixation with cannulated screws may be an acceptable option for treatment of high trochanteric fractures where a stable anatomical reduction can be obtained. We have also included a review of the literature for other reported surgical treatment options of this complication.

Patient preferences and willingness to pay for arthroplasty surgery in patients with osteoarthritis of the hip

Little is known about the economic value patients place on effective treatment of osteoarthritis (OA) of the hip. The purpose of this study was to evaluate the value of total hip arthroplasty (THA) and hip resurfacing arthroplasty (HRA) to patients with advanced hip OA by measuring their preferences and willingness to pay (WTP) for either procedure. Seventy-three patients younger than 65 years with advanced hip OA reviewed information about the risks and benefits of THA and HRA and were asked which procedure they would choose and how much they would be willing to pay for it. Sixty-nine percent of patients chose THA (average WTP, $69 419) and 31% chose HRA (average WTP, $83 195). There was no correlation between WTP and annual income or total assets. However, patients with modest income and assets could have reported that they were willing and able to pay more than they could actually afford, and WTP dropped and correlation with income rose if we excluded high responses from the poorest respondents. These results may have important policy implications as patients are asked to share a greater burden of the cost of their care for chronic conditions such as OA.

Low incidence of groin pain and early failure with large metal articulation total hip arthroplasty

BACKGROUND

Large-diameter metal-on-metal articulations reportedly improve stability and wear in THAs. However, some reports suggest some patients have unexplained hip and early failures with these implants. Thus, the potential benefits may be offset by these concerns. However, the incidence of these problems is not clearly established.

QUESTIONS/PURPOSES

We therefore assessed hip pain, function, osteolysis, and complications in patients with large-diameter metal-on-metal THA.

PATIENTS AND METHODS

We retrospectively reviewed 611 patients who had 681 large-diameter metal-on-metal THAs with the same cup and head design. The average age at operation was 62 years, 53% of the THAs were in men, and the average body mass index was 32 kg/m(2). The diagnosis was osteoarthritis in 92% of the THAs. The minimum followup was 24 months (mean, 37 months; range, 24-60 months).

RESULTS

Nine of the 611 patients (1.5%) experienced moderate or severe pain in the hip region that we considered to be coming from an extraarticular source in each case. Harris hip scores for pain averaged 42 points. Total Harris hip scores averaged 93 points. Cup abduction averaged 42°, and cup anteversion averaged 26°. There were no infections. Three cups (0.4%) were considered radiographically loose. All were secondary to inadequate seating of the shell.

CONCLUSION

Our observations suggest with this implant the concerns of higher incidences of groin pain, early failures, and adverse tissue reactions were not confirmed. Early successes or failures with large-diameter metal-on-metal articulations may be implant specific.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Cost-effectiveness of total hip arthroplasty versus resurfacing arthroplasty: economic evaluation alongside a clinical trial

OBJECTIVE

To report on the relative cost-effectiveness of total hip arthroplasty and resurfacing arthroplasty (replacement of articular surface of femoral head only) in patients with severe arthritis suitable for hip joint resurfacing arthroplasty.

DESIGN

Cost-effectiveness analysis on an intention-to-treat basis of a single-centre, single-blind randomised controlled trial of 126 adult patients within 12 months of treatment. Missing data were imputed using multiple imputations with differences in baseline quality of life and gender adjusted using regression techniques.

SETTING

A large teaching hospital trust in the UK.

PARTICIPANTS

A total of 126 adult patients with severe arthritis of the hip joint suitable for a resurfacing arthroplasty of the hip.

RESULTS

Data were received for 126 patients, 4 of whom did not provide any resource use data. For the remainder, data were imputed for costs or quality of life in at least one time point (baseline, 3, 6 months and 1 year) for 18 patients. Patients in the resurfacing arm had higher quality of life at 12 months (0.795 vs 0.727) and received 0.032 more QALYs within the first 12 months postoperation. At an additional cost of £564, resurfacing arthroplasty offers benefits at £17 451 per QALY within the first 12 months of treatment. When covariates are considered, the health economic case is stronger in men than in women.

CONCLUSIONS

Resurfacing arthroplasty appears to offer very short-term efficiency benefits over total hip arthroplasty within a selected patient group. The short-term follow-up in this trial should be noted, particularly in light of the concerns raised regarding adverse reactions to metal debris from metal-on-metal bearing surfaces in the longer term. Longer-term follow-up of resurfacing arthroplasty patients and decision analytic modelling is also advised.

TRIAL REGISTRATION

Current controlled Trials ISRCTN33354155. UKCRN 4093.

Sex differences in the morphological failure patterns following hip resurfacing arthroplasty

BACKGROUND

Metal-on-metal hybrid hip resurfacing arthroplasty (with a cementless acetabular component and a cemented femoral component) is offered as an alternative to traditional total hip arthroplasty for the young and active adult with advanced osteoarthritis. Although it has been suggested that women are less appropriate candidates for metal-on-metal arthroplasty, the mechanisms of prosthesis failure has not been fully explained. While specific failure patterns, particularly osteonecrosis and delayed type hypersensitivity reactions have been suggested to be specifically linked to the sex of the patient, we wished to examine the potential influence of sex, clinical diagnosis, age of the patient and the size of the femoral component on morphological failure patterns in a large cohort of retrieved specimens following aseptic failure of hip resurfacing arthroplasty.

METHODS

Femoral remnants retrieved from 173 hips with known patient's sex were morphologically analyzed for the cause of failure. The results were compared with the control group of the remaining 31 failures from patients of unknown sex. The odds ratios (OR) and 95% confidence intervals (CI) of the following morphologically defined variables were calculated using logistic regression analysis: periprosthetic fractures (n=133), osteonecrosis (n=151), the presence of excessive intraosseous lymphocyte infiltration (n=11), and interface hyperosteoidosis (n=30). Logistic regression analysis was performed both unadjusted and after adjustment for sex, age, the size of the femoral component, and preoperative clinical diagnosis.

RESULTS

Femoral remnants from female patients had a smaller OR for fracture (adjusted OR: 0.29, 95% CI 0.11, 0.80, P for difference=0.02) and for the presence of osteonecrosis (adjusted OR: 0.16, 95% CI 0.04, 0.63, P for difference=0.01). However, women had a higher OR for both the presence of excessive intraosseous lymphocyte infiltration (adjusted OR: 10.22, 95% CI 0.79, 132.57, P for difference=0.08) and interface hyperosteoidosis (adjusted OR: 4.19, 95% CI 1.14, 15.38, P for difference=0.03).

CONCLUSIONS

Within the limitations of this study, we demonstrated substantial sex differences in distinct failure patterns of metal-on-metal hip resurfacing. Recognition of pathogenically distinct failure modes will enable further stratification of risk factors for certain failure mechanisms and thus affect future therapeutic options for selected patient groups.

Comparison of functional results of hip resurfacing and total hip replacement: a review of the literature

Total hip arthroplasty (THA) results in good outcomes in function and risk for revision in older patients. However, in young, active patients, it results in an increased rate of revision and poorer outcomes. Modern metal-on-metal hip resurfacing arthroplasty (HRA) is described as an appropriate treatment of hip osteoarthritis in young, active patients. The selection of an appropriate prosthesis is critical for this patient demographic. This review compares the functional results of THA and HRA and focuses on range of motion, activity level, groin pain, patient satisfaction, restoration of normal hip anatomy, and gait.

Metal-on-metal: history, state of the art (2010)

The history of metal-on-metal bearing began with K. Mc Kee. Several "episodes" have marked the history of metal-on-metal articulations, and each has contributed to a better understanding of this type of tribology. But to date the indications for this bearing are debated and are subject to reservations because of the existence of permanently elevated levels of circulating metal ions. It therefore appears that the monitoring of our patients, the documentation of our revisions and the collaboration with our industry partners as well as communicating with our biology and pathology colleagues is necessary to help us solve these problems.