The evolving cost spectrum of revision hip arthroplasty

Do Conversion Total Hip Arthroplasty Yield Comparable Results to Primary Total Hip Arthroplasty?

BACKGROUND

The incidence of hip fractures is growing with the increasing elderly population. Typically, hip fractures are treated with open reduction internal fixation, hemiarthroplasty, or total hip arthroplasty (THA). Failed hip fracture fixation is often salvaged by conversion THA. The total number of conversion THA procedures is also supplemented by its use in treating different failed surgical hip treatments such as acetabular fracture fixation, Perthes disease, slipped capital femoral epiphysis, and developmental dysplasia of the hip. As the incidence of conversion THA rises, it is important to understand the perioperative characteristics of conversion THA. Some studies have demonstrated higher complication rates in conversion THAs than primary THAs, but research distinguishing the 2 groups is still limited.

METHODS

Perioperative data for 119 conversion THAs and 251 primary THAs were collected at 2 centers. Multivariable linear regression was performed for continuous variables, multivariable logistic regression for dichotomous variables, and chi-square test for categorical variables.

RESULTS

Outcomes for conversion THAs were significantly different (P < .05) compared to primary THA and had longer hospital length of stay (average 3.8 days for conversion THA, average 2.8 days for primary THA), longer operative time (168 minutes conversion THA, 129 minutes primary THA), greater likelihood of requiring metaphysis/diaphysis fixation, and greater likelihood of requiring revision type implant components.

CONCLUSION

Our findings suggest that conversion THAs require more resources than primary THAs, as well as advanced revision type components. Based on these findings, conversion THAs should be reclassified to reflect the greater burden borne by treatment centers.

Cost Variation Within Spinal Fusion Payment Groups

STUDY DESIGN

Retrospective, large administrative database.

OBJECTIVE

To investigate cost variation within current spinal fusion diagnosis-related groups (DRGs).

SUMMARY OF BACKGROUND DATA

Medicare reimbursement to hospitals for spinal fusion surgery is provided as a fixed payment for each admission based on DRG. This assumes that patients can be grouped into homogenous units of resource use such that a single payment will cover the costs of hospitalization for most patients within a given DRG. However, major differences in costs exist for different methods of spinal fusion surgery. A previous study in total joint arthroplasty (TJA) showed that variation within DRGs can lead to differences between hospital costs and Medicare reimbursement, resulting in predictable financial losses to hospitals and hindering access to care for some patients. No study to our knowledge has investigated cost variation within current spinal fusion DRGs.

METHODS

Direct hospital costs were obtained from the 2011 Nationwide Inpatient Sample (NIS) for patients in spinal fusion DRGs 453-460 and TJA DRGs 466-470. Our primary outcome was the coefficient of variation (CV), defined as the ratio of the standard deviation (SD) to the mean (CV = SD/mean × 100), for all costs within a given DRG. CVs were compared to an established TJA benchmark for within-DRG cost variation.

RESULTS

CVs for costs within spinal fusion DRGs ranged from 44.16 to 52.6 and were significantly higher than the CV of 38.2 found in the TJA benchmark group (P < 0.0001).

CONCLUSION

As in TJA, the cost variation observed within spinal fusion DRGs in this study may be leading to differences between costs and reimbursement that places undue financial burden on some hospitals and potentially compromises access to care for some patients. Future studies should seek to identify drivers of cost variation to determine whether changes can be made to further homogenize current payment groups and ensure equal access for all patients.

LEVEL OF EVIDENCE

3.

Primary vs Conversion Total Hip Arthroplasty: A Cost Analysis

INTRODUCTION

Increasing hip fracture incidence in the United States is leading to higher occurrences of conversion total hip arthroplasty (THA) for failed surgical treatment of the hip. In spite of studies showing higher complication rates in conversion THA, the Centers for Medicare and Medicaid services currently bundles conversion and primary THA under the same diagnosis-related group. We examined the cost of treatment of conversion THA compared with primary THA. Our hypothesis is that conversion THA will have higher cost and resource use than primary THA.

METHODS

Fifty-one consecutive conversion THA patients (Current Procedure Terminology code 27132) and 105 matched primary THA patients (Current Procedure Terminology code 27130) were included in this study. The natural log-transformed costs for conversion and primary THA were compared using regression analysis. Age, gender, body mass index, American Society of Anesthesiologist, Charlson comorbidity score, and smoker status were controlled in the analysis. Conversion THA subgroups formed based on etiology were compared using analysis of variance analysis.

RESULTS

Conversion and primary THAs were determined to be significantly different (P<.05) and greater in the following costs: hospital operating direct cost (29.2% greater), hospital operating total cost (28.8% greater), direct hospital cost (24.7% greater), and total hospital cost (26.4% greater).

CONCLUSIONS

Based on greater hospital operating direct cost, hospital operating total cost, direct hospital cost, and total hospital cost, conversion THA has significantly greater cost and resource use than primary THA. In order to prevent disincentives for treating these complex surgical patients, reclassification of conversion THA is needed, as they do not fit together with primary THA.

A financial analysis of revision hip arthroplasty: the economic burden in relation to the national tariff

Revision arthroplasty of the hip is expensive owing to the increased cost of pre-operative investigations, surgical implants and instrumentation, protracted hospital stay and drugs. We compared the costs of performing this surgery for aseptic loosening, dislocation, deep infection and peri-prosthetic fracture. Clinical, demographic and economic data were obtained for 305 consecutive revision total hip replacements in 286 patients performed at a tertiary referral centre between 1999 and 2008. The mean total costs for revision surgery in aseptic cases (n = 194) were £11 897 (sd 4629), for septic revision (n = 76) £21 937 (sd 10 965), for peri-prosthetic fracture (n = 24) £18 185 (sd 9124), and for dislocation (n = 11) £10 893 (sd 5476). Surgery for deep infection and peri-prosthetic fracture was associated with longer operating times, increased blood loss and an increase in complications compared to revisions for aseptic loosening. Total inpatient stay was also significantly longer on average (p < 0.001). Financial costs vary significantly by indication, which is not reflected in current National Health Service tariffs.

Cost-effectiveness of antibiotic-impregnated bone cement used in primary total hip arthroplasty

BACKGROUND

Antibiotic-impregnated bone cement is infrequently used in the United States for primary total hip arthroplasty because of concerns about cost, performance, and the possible development of antibiotic resistance and because it has been approved only for use in revision arthroplasty after infection. The purpose of this study was to model the use of antibiotic-impregnated bone cement in primary total hip arthroplasty for the treatment of osteoarthritis to determine whether use of the cement is cost-effective when compared with the use of cement without antibiotics.

METHODS

To evaluate the cost-effectiveness of each strategy, we used a Markov decision model to tabulate costs and quality-adjusted life years (QALYs) accumulated by each patient. Rates of revision due to infection and aseptic loosening were estimated from data in the Norwegian Arthroplasty Register and were used to determine the probability of undergoing a revision arthroplasty because of either infection or aseptic loosening. The primary outcome measure was either all revisions or revision due to infection. Perioperative mortality rates, utilities, and disutilities were estimated from data in the arthroplasty literature. Costs for primary arthroplasty were estimated from data on in-hospital resource use in the literature. The additional cost of using antibiotic-impregnated bone cement ($600) was then added to the average cost of the initial procedure ($21,654).

RESULTS

When all revisions were considered to be the primary outcome measure, the use of antibiotic-impregnated bone cement was found to result in a decrease in overall cost of $200 per patient. When revision due to infection was considered to be the primary outcome measure, the use of the cement was found to have an incremental cost-effectiveness ratio of $37,355 per QALY compared with cement without antibiotics; this cost-effectiveness compares favorably with that of accepted medical procedures. When only revision due to infection was considered, it was found that the additional cost of the antibiotic-impregnated bone cement would need to exceed $650 or the average patient age would need to be greater than seventy-one years before its cost would exceed $50,000 per QALY gained.

CONCLUSIONS

When revision due to either infection or aseptic loosening is considered to be the primary outcome, the use of antibiotic-impregnated bone cement results in an overall cost decrease. When only revision due to infection is considered, the model is strongly influenced by the cost of the cement and the average age of the patients. With few patients less than seventy years of age undergoing total hip arthroplasty with cement in the United States, the use of antibiotic-impregnated bone cement in primary total hip arthroplasty may be of limited value unless its cost is substantially reduced.

An analysis of medicare payment policy for total joint arthroplasty

Medicare facility payment policy for lower extremity total joint arthroplasty (TJA) has undergone extensive changes since 2005. The purpose of this study was to compare patient and procedure characteristics and resource use among TJA procedures and to identify predictors of resource use in TJA. Clinical, demographic, and economic data were analyzed from 6483 primary or revision TJA patients from 4 high-volume centers between October 2005 and June 2006. Descriptive analyses were conducted to evaluate differences between procedure types, and multivariable linear regression analyses were undertaken to identify predictors of resource use. Both patient severity of illness and surgical complexity influenced resource use associated with TJA procedures. As the primary goal of Medicare payment policy is to set payment rates proportional to relative resource use, both severity of illness and surgical complexity should be incorporated for payment equity and to minimize incentives for selection bias among hospitals that perform TJA procedures.

Differences in patient and procedure characteristics and hospital resource use in primary and revision total joint arthroplasty: a multicenter study

A multicenter retrospective cost-identification cohort study was undertaken to analyze clinical, demographic, and economic data for 4533 consecutive total hip arthroplasty (THA) and 3508 consecutive total knee arthroplasty (TKA) procedures performed during a 3-year period in 1 of 3 hospitals. Statistically significant differences were found between primary and revision procedures with respect to patient age, sex, payer type, mean total operative time, use of allograft, average length of hospital stay, discharge disposition, and hospital costs. Significant differences were also found between different types of revision total joint arthroplasty (TJA) procedures. Our findings could be used to help improve the accuracy of administrative claims data related to primary and revision TJA procedures to identify relevant differences in patient characteristics, procedure characteristics, and hospital resource use.

Hospital resource utilization for primary and revision total hip arthroplasty

BACKGROUND

Previous reports have suggested that hospital resource utilization for revision total hip arthroplasty is substantially higher than that for primary total hip arthroplasty. However, current United States Medicare hospital-reimbursement policy does not distinguish between the two procedures. The purpose of this study was to compare primary and revision total hip arthroplasties with regard to actual hospital resource utilization and to identify clinical and demographic factors that are predictive of higher resource utilization associated with these procedures.

METHODS

We evaluated the clinical, demographic, and economic data associated with 491 consecutive unilateral primary or revision total hip arthroplasties performed by two surgeons at a single institution between January 2000 and December 2002. The distributions of various demographic, clinical, and utilization characteristics were compared between the two types of arthroplasty procedures, and multivariable linear regression techniques were used to determine independent patient characteristics that were predictive of higher costs for both the primary and the revision procedures.

RESULTS

The mean total hospital cost was $31,341 for the revision procedures compared with $24,170 for the primary procedures (p < 0.0001). The mean operative time was 41% longer for the revisions than for the primary procedures (4.5 hours compared with 3.2 hours, p < 0.0001), the mean estimated blood loss was 160% higher (1348 mL compared with 518 mL, p < 0.0001), the mean complication rate was 32% higher (29% compared with 22%, p = 0.072), and the mean length of the hospital stay was 16% longer (6.5 days compared with 5.6 days, p = 0.0005). A higher severity-of-illness score (a measure of preoperative medical health) was predictive of higher resource utilization for both primary and revision arthroplasty even after adjustment for other factors. Preoperative femoral and ace-tabular bone loss and a diagnosis of periprosthetic fracture were predictive of higher resource utilization associated with revision procedures.

CONCLUSIONS

At one institution, hospital resource utilization for revision total hip arthroplasty was found to be significantly higher than that for primary arthroplasty. This information is not reflected by current United States Medicare hospital reimbursement, which is the same for all lower-extremity arthroplasty procedures, regardless of the diagnosis, the complexity of the procedure, or the patient's baseline medical health. If these findings are generalizable to other institutions, appropriate reimbursement formulas should be developed to accurately reflect the true costs of caring for patients with a failed total hip arthroplasty.

Economic evaluation in total hip arthroplasty: analysis and review of the literature

We performed a bibliographic search of MEDLINE databases from January 1966 to July 2002 to identify English language articles that contained either "cost" or "economic" in combination with "total hip arthroplasty" (THA) in the abstract or title. Each study was then critically reviewed for content, technique, and adherence to established healthcare economic principles. Only 81 of the 153 studies retrieved contained actual economic data. Only 6% of studies adhered to established criteria for a comprehensive health care economic analysis. Although the number of publications regarding economic evaluation of THA is on the rise, the methodologic quality of many of these studies remains inadequate. Future studies should employ sound healthcare economic techniques to properly evaluate and assess the true social and economic value of THA.