- Email: [email protected]
Current and Projected Utilization of Total Joint Replacements
6.601.
Current and Projected Utilization of Total Joint Replacements
S M Kurtz, Exponent, Inc., Philadelphia, PA, USA; Drexel University, Philadelphia, PA K L Ong, Exponent, Inc., Philadelphia, PA, USA E Lau, Exponent Inc., Menlo Park, CA, USA M T Manley, Homer Stryker Center for Orthopaedic Education and Research, Mahwah, NJ, USA ã 2011 Elsevier Ltd. All rights reserved.
6.601.1. 6.601.2. 6.601.3. 6.601.3.1. 6.601.3.2. 6.601.3.3. 6.601.4. 6.601.5. 6.601.6. References
Introduction International Total Hip and Knee Implant Registries Public Data Sources for Orthopedic Implant Utilization in the United States National Hospital Discharge Survey Nationwide Inpatient Sample Medicare Current Utilization of Total Joint Replacements Projected Utilization of Total Joint Replacements Summary
Glossary 9th revision of the international classification of diseases, clinical modification (ICD-9-CM) Classification used in assigning codes to diagnoses and procedures associated with inpatient, outpatient, and physician office utilization in the United States. National hospital discharge survey (NHDS) Annual survey conducted by the National Center for Health Statistics, representing a sample of hospitalization from
Abbreviations AAOS AHRQ CI CMS HCUP LDS
6.601.1.
American academy of orthopaedic surgeons Agency of healthcare quality and research Confidence intervals Center for medicare and medicaid services Healthcare cost & utilization project Limited data set
Introduction
Hip and knee joint replacement surgery is currently the standard of care for treating degenerative joint disease around the world. The prevalence of hip and knee arthroplasty in the United States has grown substantially since the 1990s.1 Arthroplasty may involve total replacement of a diseased joint, or in the case of a hip fracture or single compartment knee arthritis, only one side of the joint may be surgically replaced by a partial joint prosthesis. The first time a joint is replaced, it is referred to as a primary procedure, but in the case of a failed surgery, it is necessary to perform a revision joint replacement. Considering both primary and revision procedures, over 1 million Americans benefited from partial and total joint
1 2 3 3 3 4 4 6 7 8
non-Federal and non-military short-stay community hospitals throughout the United States. National implant registry Repository of information collected on a national basis to quantify rates of surgeries for particular types of procedures and/or devices, which is used to provide feedback related to procedure outcomes. Nationwide inpatient sample (NIS) Database of inpatient discharge data sampled from inpatient hospital visits in the United States.
LOS NCHS NHDS NIS THA THR TJA TKA
Length of stay National center for health statistics National hospital discharge survey Nationwide inpatient sample Total hip arthroplasty Total hip replacement Total joint arthroplasty Total knee arthroplasty
replacement surgery in 2007. The different categories of primary and revision joint arthroplasty thus represent an established major platform for ongoing biomaterials advancement. Because the cost, complications, and outcomes of revision joint replacement are generally worse than in primary surgery, there is great incentive to increase the longevity of joint replacements and to reduce the incidence of revisions. As a result, starting in the 1970s, orthopedic registries were developed in Scandinavia to track revisions on a national basis as a function of surgeon, patient, and implant characteristics.2 In recent years, orthopedic registries have expanded across Europe, Canada, Australia, and New Zealand. Efforts to create a national orthopedic registry are still in the early stages in the United States. The sense of urgency surrounding a US arthroplasty
1
2
Orthopedic Surgery – Joint Replacement
Table 1
Examples of international total joint registries
Starting year of available total joint registries data
Register
Website
1979 1975 1987 1999 1994 1998 2003
Swedish National Hip Arthroplasty Register Swedish Knee Arthroplasty Register Norwegian Arthroplasty Register Australian National Joint Replacement Registry Canadian Joint Replacement Registry New Zealand National Joint Register England and Wales National Joint Registry
http://www.shpr.se/ http://www.knee.nko.se/ http://www.haukeland.no/nrl/ http://www.dmac.adelaide.edu.au/aoanjrr/ http://secure.cihi.ca/cihiweb/dispPage.jsp?cw_page¼services_cjrr_e http://www.cdhb.govt.nz/NJR/ http://www.njrcentre.org.uk/
6.601.2. International Total Hip and Knee Implant Registries International registries represent a well-established source of data regarding the current use of total joint replacement in Canada, Europe, and Australasia (Table 1). A registry is not merely a data repository containing basic clinical, patient, and implant data regarding the implantation and revision of total joint replacements. In countries in which an implant registry has been established, the data is also used as a tool to drive health care improvement by providing continuous feedback to the clinical community about procedure outcomes. Orthopedic implant registries were first established in the 1970s in Sweden and later spread throughout Europe, Australia, and New Zealand. For example, the Swedish knee registry chronicles the growth of knee arthroplasty since the very beginnings of the procedure in the country (Figure 1). From the example of growth in Swedish total knee arthroplasty (TKA) utilization it may be appreciated that the characteristics and usage patterns of joint replacement vary considerably as a function of time. The temporal dimension greatly complicates comparisons among registries, which were established at different time periods and contain varying follow up. Thus, in the evaluation of clinical failure modes and their relationship to biomaterials across and between different registries, appreciation of the temporal variable is important. If the long-term goal of a registry program is to improve the overall process of joint arthroplasty, tracking hospitalization outcomes (revisions, complications) is but the starting point
Yearly incidence of knee arthroplasty (100 000) 140 120
Females Males
100 80 60 40 20 0 1975 1980 1985 1990 1995 2000 2005 Year of operation
Copyright © 2009 SKAR
registry is compelling due to the anticipated future demand for joint arthroplasty. In the absence of a validated joint registry, administrative health care data in the United States represent a crucial resource in understanding the current and projected utilization of hip and knee replacements. The purpose of this chapter is to provide a comprehensive review of the utilization of joint replacements and to discuss the implications of the future demand for surgeries in the field of biomaterials. As they are the earliest source of utilization data for joint replacement, international joint registries and validated administrative databases are first summarized and compared. The projected demand for joint replacements between 2010 and 2030 is also addressed. Finally, we review the limitations of the projection techniques and outline the economic implications of an escalating demand for joint replacement surgery in the future.
Figure 1 Annual incidence of knee arthroplasty in Sweden per 100 000 persons. Source: Swedish Knee Arthroplasty Register, Lund, Sweden.
for tracking the contribution joint arthroplasty makes to society. In its first 22 years of operation the Swedish hip registry focused on clinical metrics of surgery outcomes. However, since 2001, this registry has placed increasing emphasis on documenting improvement of the patients’ quality of life following the surgery as well as the societal cost of performing the procedure. In many countries with a socialized health care system, including Sweden and Canada, the waiting time for surgery can be substantial. In Sweden, the mean wait time for total hip arthroplasty (THA) surgery was 312 days in 2007, whereas in Canada, the mean wait time was 182 days for THA. According to an economic analysis conducted by the Swedish hip registry, the societal cost for 1 year of wait time, incorporating lost productivity, is equivalent to the inpatient procedure cost of the surgery itself. Thus, the data from hip registries may be developed to drive changes in health care policy (e.g., reducing wait times in Sweden and Canada). Differences in health care delivery and access to joint replacement surgery cause wide variations in THA access between countries, as well as within countries over time. For example, within a country shifts in policy toward reducing wait times may increase the rate at which surgery is performed, even for a pool of patients that is not rapidly changing. Thus, policy shifts are but one example of the need for care
Current and Projected Utilization of Total Joint Replacements
in extrapolating the current and projected utilization of hip and knee surgery outside of its national health care system. Registries represent an important tool to evaluate the current use of total joint replacements in various countries, but they are by no means the only source of data regarding the utilization of surgical procedures. Large countries such as Germany and the United States currently do not have an operating hip and knee registry. Nationally representative administrative databases of countries without an operational registry are covered in the following section of this chapter. These databases can provide valuable and otherwise unavailable data regarding the current use of total hip and knee arthroplasty in the absence of a formal registry.
6.601.3. Public Data Sources for Orthopedic Implant Utilization in the United States Even in countries with an established registry, administrative databases represent an important data source for total joint replacements. An administrative database may comprise a sampling of electronic hospital discharge records, or in the case of Medicare, the entire insurance claim history for individual patients. Total hip and knee procedures are identified in these databases according to the codes from the 9th Revision of the International Classification of Diseases, Clinical Modification (ICD-9-CM; see Table 2). Three public sources of administrative claims data for the United States are summarized in the following subsections.
6.601.3.1. National Hospital Discharge Survey The National Hospital Discharge Survey (NHDS)3 is an annual survey conducted by the National Center for Health Statistics (NCHS). Started in 1965, this survey program has continuously Table 2
3
compiled a statistically representative sample of hospitalization from non-Federal and non-military short-stay community hospitals throughout the United States. As such, it is the oldest and most well-established inpatient discharge database in the country. Over the past decade, the number of hospitals included in NHDS has ranged from 430 to 490, with 300 000 discharge records sampled per year. Information collected by NHDS includes patient demographics (e.g., age, gender), disease diagnosis, type of procedure performed, institutional characteristics, and resource utilization. Based on the information collected by the survey, national and regional estimates of characteristics of patients and surgical and nonsurgical procedures in hospitals of various bed sizes and types of ownership can be estimated using the provided sampling weights.
6.601.3.2. Nationwide Inpatient Sample The Nationwide Inpatient Sample (NIS) is a larger and more recent database of inpatient discharge data in comparison with the NHDS.4 Established in 1988 by the Healthcare Cost & Utilization Project (HCUP) of the Agency of Healthcare Quality and Research (AHRQ), the NIS has a far larger sample size in terms of both discharge records and number of hospitals. Compared to the NHDS, the NIS has 25 times more records with 5–8 million records per year and also includes twice the number of hospitals. The sampling of NIS captures 20% of inpatient hospital visits each year in the United States, and thus is well suited for studying national trends for rare diseases or for examining the epidemiology of diagnoses or procedures within minority subpopulations. The NIS also captures patient, payer, and hospitalization factors, as well as charges and cost information for the hospitalization, which can be used to evaluate the economic impact of procedures and diagnoses.
Summary of ICD-9-CM codes for primary and revision total hip and knee replacement procedures
ICD9-CM-Code
Description
Comments
81.51 81.52
Primary total hip replacement Partial hip replacement
81.53 81.54
Revision of hip replacement, not otherwise specified Primary total knee replacement
The type of bearing surface is coded, if known (00.74–0.77) This includes unipolar and bipolar hip prostheses; the type of bearing surface is coded, if known (00.74–0.77) The type of bearing surface is coded, if known (00.74–0.77) This code includes bicompartmental, tricompartmental, and unicondylar knee arthroplasty
81.55 00.70
Revision of knee replacement, not otherwise specified Revision of hip replacement, both acetabular and femoral components Revision of hip replacement, acetabular component Revision of hip replacement, femoral component Revision of hip replacement, acetabular liner and/or femoral head only Hip bearing surface, metal-on-polyethylene Hip bearing surface, metal-on-metal Hip bearing surface, ceramic-on-ceramic Hip bearing surface, ceramic-on-polyethylene Revision of knee replacement, total (all components) Revision of knee replacement, tibial component Revision of knee replacement, femoral component Revision of knee replacement, patellar component Revision of total knee replacement, tibial insert (liner)
00.71 00.72 00.73 00.74 00.75 00.76 00.77 00.80 00.81 00.82 00.83 00.84
Introduced 1 October 2005 Introduced 1 October 2005 Introduced 1 October 2005 Introduced 1 October 2005 Introduced 1 October 2005 Introduced 1 October 2005 Introduced 1 October 2005 Introduced 1 October 2006 Introduced 1 October 2005 Introduced 1 October 2005 Introduced 1 October 2005 Introduced 1 October 2005 Introduced 1 October 2005
4
Orthopedic Surgery – Joint Replacement
6.601.3.3. Medicare The 5% Medicare so-called Limited Data Set (LDS) is available from the Center for Medicare and Medicaid Services (CMS). The complete 5% dataset consists of seven components: hospital inpatient, hospital outpatient, home health agency, skilled nursing facility, hospice care, physician carrier (Part B), and durable medical equipment. A denominator file is also available that tracks the date of death or (more rarely) withdrawal by Medicare beneficiaries from the program. In the LDS, patients are uniquely identified by an encrypted Medicare beneficiary identification number that remains consistent across all parts of the database as well as over time. In this way, the utilization of healthcare resources by a patient can be tracked in different health care settings (i.e., both inpatient and outpatient), as well as in home hospice care, and during physician office visits.
6.601.4. Current Utilization of Total Joint Replacements The number and prevalence of primary hip and knee replacement procedures have increased substantially in the United States between 1993 and 2006, most notably for primary TKA
(Figure 2). The number of primary TKA and primary THA increased by 148% and 66%, respectively, during this period, corresponding to compound annual growth rates of 7.2% and 4.0%. The number of revision TKA and THA grew by 142% and 29%, respectively, with corresponding compound annual growth rates of 7.0% and 2.0%. Even after adjusting for population changes, the increase in procedure rates since 1993 was also evident, along with the slowdown in the prevalence of primary and revision THA and primary TKA between 2005 and 2006 (Figure 3). To normalize the incidence of revision surgery, previous researchers from the Scandinavian registries have introduced the concept of a national revision burden, which is the ratio of revisions performed in a year to the total number of procedures (primary þ revision). Using the 1993–2006 NIS dataset, the US mean revision burden of 16.2% (range 13.9–17.8%) for THA was approximately twice that for TKA (7.9%; range 7.3–8.4%; see Tables 3 and 4). The greater revision burden for THA compared to TKA is consistent with the relative revision burden in Canada which is 2.1 times greater than primary6 and Finland which is 2.2 times greater.7 The US mean revision burden for THA is also 65% greater than for TKA in Australia8 and 78% greater than for Norway.9
600 000
Procedures
500 000
Primary THA Primary TKA
400 000
300 000
200 000
100 000 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 Year 50 000 45 000
Revision THA Revision TKA
Procedures
40 000 35 000 30 000 25 000 20 000 15 000 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 Year Figure 2 Annual number of primary (top panel) and revision (bottom panel) total hip arthroplasty and total knee arthroplasty in the United States. Note difference in y-axis scales.
Current and Projected Utilization of Total Joint Replacements
5
200
Procedure rates (per 100 000 persons)
175 150
Primary THA Primary TKA
125 100 75 50 25 0 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 Year
Procedure rates (per 100 000 persons)
25 20
Revision THA Revision TKA
15 10 5 0 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 Year
Figure 3 Annual incidence of primary (top panel) and revision (bottom panel) total hip arthroplasty and total knee arthroplasty in the United States per 100 000 persons.
Table 3
Mean revision burden for THA
Country
Period
Revision burden (%)
Reference
United States Australia Canada Finland Norway Sweden
1993–2006 2003–2007 2002–2006 1997–2006 1993–2007 2003–2007
16.2 15.7 12.4 17.3 14.6 10.1
Nationwide Inpatient Sample Australian Orthopaedic Association – National Joint Replacement Registry Canadian Institute for Health Information National Agency for Medicines The Norwegian Arthroplasty Register Swedish Hip Arthroplasty Register
Table 4
Mean revision burden for TKA
Country
Period
Revision burden (%)
Source
United States Australia Canada Finland Norway Sweden
1993–2006 2003–2007 2002–2006 1997–2006 1993–2007 1991–2003
7.9 9.5 6.1 7.9 8.2 4–7
Nationwide Inpatient Sample Australian Orthopaedic Association – National Joint Replacement Registry Canadian Institute for Health Information National Agency for Medicine Norwegian Arthroplasty Register Robertsson5
Overall, the THA revision burden in the United States is comparable to Australia8 and Finland7 (Table 3). Compared to the United States, the mean revision burden in Norway,9 Canada,6 and Sweden10 are all lower. For TKA (Table 4), the
US mean revision burden is comparable with the revision burdens of Norway9 and Finland.7 Compared to the United States, the knee revision burden is slightly lower in Canada6 and in Sweden,5 and slightly higher in Australia.8
6
Orthopedic Surgery – Joint Replacement
In addition to revision procedures, the level of specificity in the ICD-9-CM codes makes it possible to perform national epidemiologic studies of postoperative complications in the US population. In a study by Kurtz et al.,11 of periprosthetic infection between 1990 and 2004, the incidence of infection for both hip and knee arthroplasties in the United States nearly doubled from about 0.6% to 1.2%. The odds of infection increased annually at a rate of 5% (odds ratio: 1.049; 95% confidence intervals (CI): 1.04–1.06). The length of stay (LOS) for infected TJAs was close to twice as long as for uninfected TJAs (2.21 times longer for THA, 95% CI: 2.18–2.23 times longer; and 1.87 times longer for TKA, 95% CI: 1.85–1.88 times longer) (p < 0.0001 for both). Furthermore, the ratio in LOS between infected and uninfected TJA has been on a widening trend between 1990 and 2004, with a rate of increase at 1.15% from year to year. The corresponding charge ratio for infected TJAs was also significantly greater (p < 0.001). This study highlighted an increasing trend of infected hip and knee arthroplasties in the United States. As demonstrated by the greater LOS and hospitalization charges/costs for infected TJA in this study and others,12 the economic impact of deep infection is substantial. This infection research illustrates how administrative data from the NIS can be effectively used to quantify the national burden of specific total joint arthroplasty (TJA) complications, in addition to revision. Recently, additional specificity provided in the ICD-9-CM procedure and diagnosis codes has greatly strengthened administrative databases as tools to examine national trends of TJA failure modes and revision strategies. In October 2005, based on a request from a group of orthopedic and health services researchers, the CMS and the NCHS implemented a series of changes to the ICD-9-CM diagnosis and procedure codes13 (Table 2). These changes included new procedure codes that specify the THA bearing type, as well as new diagnosis and procedure codes to specify the cause of failure (e.g., dislocation, loosening, etc.) and type of component revised (e.g., acetabular component only, femoral component only, etc.) for revision THA. The availability of new bearing surface codes, revision diagnosis codes, and revision procedure codes provides an unprecedented opportunity to evaluate the comparative effectiveness of Total hip replacement (THR) bearing surfaces using administrative data. Based on the new revision diagnosis and procedure codes, the epidemiology of revision THA was evaluated using the NIS database.14 Based on a sample of 51 345 revision THA procedures spanning 1.25 years from October 2005 to December 2006, instability/dislocation was the most commonly reported cause of revision THA (22.5%), followed by mechanical loosening (19.7%) and infection (14.8%). All component revisions were most frequently reported (41.1%), followed by femoral component revision (13.2%), acetabular component revision (12.7%), isolated femoral head and acetabular liner exchange (12.6%), and arthrotomy (9.1%). Despite the increasing adoption of large diameter heads for THA over the recent years, this analysis indicated that dislocation remains the primary diagnosis reported for revision THA. In summary, it can be seen that, based on data from administrative databases and national total joint registries, the current utilization of total joint replacements has been
increasing over time. Despite the recognized success of these procedures, the number of revision procedures continues to increase for both THA and TKA. Minimizing revisions and complications continues to be a clinical concern and a major financial need.
6.601.5. Projected Utilization of Total Joint Replacements Projections are important for guiding health care policy. In 2002, the American academy of orthopedic surgeons (AAOS) published projections of primary total hip and total knee replacement surgery through 2030, based on surgery rates calculated from the 1996 to 1999 hospitalization data from the NHDS and US Census projections for the next 30 years.15 It is now clear that these projections by the AAOS underpredicted the expected utilization of primary TJA because the estimates of the surgery rates assumed a constant prevalence based on the average rate over the 4 years of the 1996–99 NHDS dataset and did not account for any year-to-year change in the rate itself. Thus, the projected growth in the number of hip and knee replacements in the AAOS model was fueled solely by the anticipated growth of the US population and was also limited to primary TJA without consideration for revision procedures. Since revision procedures place extensive additional demands on hospitals and surgeons and on medical costs, these should be considered in an analysis of projected future rates and population-based costs of arthroplasty procedures to the US health care system. Motivated by the limitations in the prior projections, the authors used a much larger data source in the form of the NIS data, which has 25 times more discharge records than the NHDS.16,17 These projections16 were based on 1990–2003 NIS data and the historical trajectory of surgery rates. They estimated the demand for primary THA to grow by 174%, from 208 600 in 2005 to 572 000 by 2030. The demand for primary TKA was also projected to grow more than sixfold, from 450 000 (95% prediction interval: 425 000–477 000) in 2005 to 3.48 million procedures (95% prediction interval: 2.95–4.14 million) by 2030. Revision TJA were also estimated to grow substantially from 40 800 to 96 700 for THA (an increase of 137%) and from 38 300 to 268 200 for TKA (an increase of 601%) between 2005 and 2030. Following these initial projections, three additional years of NIS data (2004–2006) became available, allowing the comparison of previous projections with the recent NIS data, updating of the previous projections, and further demographic analysis of the projections. The previous projections16 provided reasonably accurate estimates of the primary and revision TJA trends between 2004 and 2006,17 particularly for revision TJA procedures, which were within the 95% CI of the previous projections. However, the previous projections underestimated the historical number of primary TJA procedures. Based on the additional 2004–2006 NIS data, the projections were reanalyzed, incorporating a ‘variable rate’ and a ‘constant rate’ approach to provide upper and lower prediction bounds, respectively. The ‘variable rate’ approach was consistent with the previous analysis, which allowed both the population and prevalence of surgery to vary over time. Conversely, the
Current and Projected Utilization of Total Joint Replacements
7
4500
Procedures (⫻1000)
4000 3500
Primary THA Primary TKA
3000 2500 2000 1500 1000 500 0 2010
2015
2020
2025
2030
2025
2030
Year 450
Procedures (⫻1000)
400 350
Revision THA Revision TKA
300 250 200 150 100 50 0 2010
2015
2020 Year
Figure 4 Projected annual demand for primary (top panel) and revision (bottom panel) total hip arthroplasty and total knee arthroplasty in the United States through the year 2030.
‘constant rate’ approach allowed the population to vary over time, but assumed that the future prevalence of surgery was constant, which was based on the average rate between 2004 and 2006. Based on the updated projections,17 the number of primary THA was predicted to increase from 229 900 procedures in 2006 to between 345 700 (constant rate) and 891 800 (variable rate) procedures in 2030 (Figure 4). Primary TKA was also predicted to increase from 524 600 procedures to between 792 200 (constant rate) and 4.34 million (variable rate) procedures over the same time period (Figure 4). Due to the relatively stable historical revision burden rates, the predicted demand for revision TJA is expected to be driven primarily by the increase in demand for primary procedures. Revision THA and TKA were projected to increase from 37 200 and 46 400 to 59 000 (constant rate)–91 400 (variable rate) and 64 600 (constant rate)–339 000 (variable rate), respectively, between 2006 and 2030. If the trajectory of surgery prevalence were to continue into the future, the demand for primary THA and TKA among younger patients, that is, patients <65 years old, will be projected to exceed 50% of all THA and TKA patients by 2011 and 2016, respectively. Younger patients will also be projected to exceed 50% of the revision TKA patient population by 2011. By 2030, the demand for TJA by younger patients aged <65 years will comprise 52% of primary THAs and 55–62% of primary or revision TKAs.
Based on the projected demand for primary and revision TJA, the corresponding economic impact in terms of hospitalization cost was also computed. By using the costto-charge ratio files provided in the NIS dataset to convert hospitalization charges to costs, the historical changes in average procedure costs were then projected for 2030. By combining the projected number of procedures and the projected costs for each procedure, the overall cost projections for primary and revision TJA were estimated. If the historical growth trajectory of procedure demand and costs continues, the overall cost for primary THA and TKA were projected to increase from $3.5 to $25.1 billion (95% CI: $14.9–40.4 billion) and from $7.0 to $92.9 billion (95% CI: $58.8–$144.6 billion), respectively (Figure 5). The economic burden for revision THA and TKA was also projected to increase from $712 million to $2.9 billion (95% CI: $1.1–$5.8 billion) and from $718 million to $13.9 billion (95% CI: $6.6–$27.1 billion), respectively.
6.601.6.
Summary
In summary, the analyses of current and projected utilization for joint arthroplasty predict a massive anticipated demand for these procedures in the coming decades. However, the current economic and regulatory climate for health care
8
Orthopedic Surgery – Joint Replacement
Total cost ($ million)
150 000 Primary THA Primary TKA 100 000
50 000
0 2010
2015
2020 Year
2025
2030
2020 Year
2025
2030
30 000
Total cost ($ million)
25 000
Revision THA Revision TKA
20 000 15 000 10 000 5000 0 2010
2015
Figure 5 Projected annual cost of primary (top panel) and revision (bottom panel) total hip arthroplasty and total knee arthroplasty in the United States through the year 2030.
innovation is more challenging than ever before. New biomaterials for total joint replacement must be engineered to reduce widely recognized current complications such as loosening, dislocation, and infection for existing patient populations and to provide new functional capabilities to younger and more active patients. Technologies that only provide improved outcomes at 10þ years of service will require increased health economic justification. As scientists develop new biomaterials for the future joint replacement market, it is essential for commercial success that the studies to prove the cost effectiveness of these new technologies be designed and fully appreciated at the onset of the research and development phase in the product lifecycle.
References 1. Kurtz, S.; Mowat, F.; Ong, K.; Chan, N.; Lau, E.; Halpern, M. J. Bone Joint Surg. Am. 2005, 87, 1487–1497. 2. Malchau, H.; Herberts, P.; Ahnfelt, L. Acta Orthop. Scand. 1993, 64, 497–506. 3. National Center for Health Statistics. National Hospital Discharge Survey Description, 2009. 4. Agency for Healthcare Research and Quality. HCUP Databases. Healthcare Cost and Utilization Project (HCUP), 2008.
5. Robertsson, O. J. Bone Joint Surg. Br. 2007, 89, 1–4. 6. Canadian Institute for Health Information. Canadian Joint Replacement Registry (CJRR). 2007 Annual Report – Hip and Total Knee Replacements in Canada, 2008. 7. National Agency for Medicines. The 2006 Implant Yearbook on Orthopaedic Endoprostheses: Finnish Arthroplasty Register, 2008. 8. Australian Orthopaedic Association – National Joint Replacement Registry. Hip and knee arthroplasty, Annual report 2008. 9. The Norwegian Arthroplasty Register. Report 2008. 10. Swedish Hip Arthroplasty Register. Swedish Hip Arthroplasty Register, Annual Report 2007, 2008. 11. Kurtz, S. M.; Lau, E.; Schmier, J.; Ong, K. L.; Zhao, K.; Parvizi, J. J. Arthroplasty 2008, 23(7), 984–991. 12. Bozic, K. J.; Ries, M. D. J. Bone Joint Surg. Am. 2005, 87, 1746–1751. 13. Bozic, K. J.; Katz, P. P.; Showstack, J. A.; et al. The use of clinical and economic outcomes data to influence health policy in the United States: The case of total joint replacement, OREF Clinical Outcomes Research Award Paper. Presented at the 73rd Annual Meeting of the American Academy of Orthopaedic Surgeons, Chicago, IL, 2006. 14. Bozic, K. J.; Kurtz, S. M.; Lau, E.; Ong, K.; Vail, T. P.; Berry, D. J. J. Bone Joint Surg. Am. 2009, 91, 128–133. 15. Frankowski, J. J.; Watkins-Castillo, S. Primary Total Knee and Hip arthroplasty Projections for the US Population to the Year 2030, 2002. 16. Kurtz, S.; Ong, K.; Lau, E.; Mowat, F.; Halpern, M. J. Bone Joint Surg. Am. 2007, 89, 780–785. 17. Kurtz, S. M.; Lau, E.; Ong, K.; Zhao, K.; Kelly, M.; Bozic, K. J. Clin. Orthop. Relat. Res. 2009, 467(10), 2606–2612 [Epub Apr 10].
Current and Projected Utilization of Total Joint Replacements
Relevant Websites http://www.shpr.se/ – Swedish Hip Arthroplasty Register. http://www.knee.nko.se/ – Swedish Knee Arthroplasty Register. http://www.haukeland.no/nrl/ – The Norwegian Arthroplasty Register. http://www.dmac.adelaide.edu.au/aoanjrr/ – The National Joint Replacement Registry (Australia).
http://www.cdhb.govt.nz/NJR/ – National Joint Register (New Zealand). http://www.njrcentre.org.uk/ – National Joint Registry (UK). http://www.cdc.gov/nchs/nhds.htm – National Hospital Discharge Survey (USA). http://www.hcup-us.ahrq.gov/nisoverview.jsp – Overview of the Nationwide Inpatient Sample (NIS). http://www.cms.hhs.gov/LimitedDataSets/ – Centers for Medicare & Medicaid Services.
9
Current and Projected Utilization of Total Joint Replacements
S M Kurtz, Exponent, Inc., Philadelphia, PA, USA; Drexel University, Philadelphia, PA K L Ong, Exponent, Inc., Philadelphia, PA, USA E Lau, Exponent Inc., Menlo Park, CA, USA M T Manley, Homer Stryker Center for Orthopaedic Education and Research, Mahwah, NJ, USA ã 2011 Elsevier Ltd. All rights reserved.
6.601.1. 6.601.2. 6.601.3. 6.601.3.1. 6.601.3.2. 6.601.3.3. 6.601.4. 6.601.5. 6.601.6. References
Introduction International Total Hip and Knee Implant Registries Public Data Sources for Orthopedic Implant Utilization in the United States National Hospital Discharge Survey Nationwide Inpatient Sample Medicare Current Utilization of Total Joint Replacements Projected Utilization of Total Joint Replacements Summary
Glossary 9th revision of the international classification of diseases, clinical modification (ICD-9-CM) Classification used in assigning codes to diagnoses and procedures associated with inpatient, outpatient, and physician office utilization in the United States. National hospital discharge survey (NHDS) Annual survey conducted by the National Center for Health Statistics, representing a sample of hospitalization from
Abbreviations AAOS AHRQ CI CMS HCUP LDS
6.601.1.
American academy of orthopaedic surgeons Agency of healthcare quality and research Confidence intervals Center for medicare and medicaid services Healthcare cost & utilization project Limited data set
Introduction
Hip and knee joint replacement surgery is currently the standard of care for treating degenerative joint disease around the world. The prevalence of hip and knee arthroplasty in the United States has grown substantially since the 1990s.1 Arthroplasty may involve total replacement of a diseased joint, or in the case of a hip fracture or single compartment knee arthritis, only one side of the joint may be surgically replaced by a partial joint prosthesis. The first time a joint is replaced, it is referred to as a primary procedure, but in the case of a failed surgery, it is necessary to perform a revision joint replacement. Considering both primary and revision procedures, over 1 million Americans benefited from partial and total joint
1 2 3 3 3 4 4 6 7 8
non-Federal and non-military short-stay community hospitals throughout the United States. National implant registry Repository of information collected on a national basis to quantify rates of surgeries for particular types of procedures and/or devices, which is used to provide feedback related to procedure outcomes. Nationwide inpatient sample (NIS) Database of inpatient discharge data sampled from inpatient hospital visits in the United States.
LOS NCHS NHDS NIS THA THR TJA TKA
Length of stay National center for health statistics National hospital discharge survey Nationwide inpatient sample Total hip arthroplasty Total hip replacement Total joint arthroplasty Total knee arthroplasty
replacement surgery in 2007. The different categories of primary and revision joint arthroplasty thus represent an established major platform for ongoing biomaterials advancement. Because the cost, complications, and outcomes of revision joint replacement are generally worse than in primary surgery, there is great incentive to increase the longevity of joint replacements and to reduce the incidence of revisions. As a result, starting in the 1970s, orthopedic registries were developed in Scandinavia to track revisions on a national basis as a function of surgeon, patient, and implant characteristics.2 In recent years, orthopedic registries have expanded across Europe, Canada, Australia, and New Zealand. Efforts to create a national orthopedic registry are still in the early stages in the United States. The sense of urgency surrounding a US arthroplasty
1
2
Orthopedic Surgery – Joint Replacement
Table 1
Examples of international total joint registries
Starting year of available total joint registries data
Register
Website
1979 1975 1987 1999 1994 1998 2003
Swedish National Hip Arthroplasty Register Swedish Knee Arthroplasty Register Norwegian Arthroplasty Register Australian National Joint Replacement Registry Canadian Joint Replacement Registry New Zealand National Joint Register England and Wales National Joint Registry
http://www.shpr.se/ http://www.knee.nko.se/ http://www.haukeland.no/nrl/ http://www.dmac.adelaide.edu.au/aoanjrr/ http://secure.cihi.ca/cihiweb/dispPage.jsp?cw_page¼services_cjrr_e http://www.cdhb.govt.nz/NJR/ http://www.njrcentre.org.uk/
6.601.2. International Total Hip and Knee Implant Registries International registries represent a well-established source of data regarding the current use of total joint replacement in Canada, Europe, and Australasia (Table 1). A registry is not merely a data repository containing basic clinical, patient, and implant data regarding the implantation and revision of total joint replacements. In countries in which an implant registry has been established, the data is also used as a tool to drive health care improvement by providing continuous feedback to the clinical community about procedure outcomes. Orthopedic implant registries were first established in the 1970s in Sweden and later spread throughout Europe, Australia, and New Zealand. For example, the Swedish knee registry chronicles the growth of knee arthroplasty since the very beginnings of the procedure in the country (Figure 1). From the example of growth in Swedish total knee arthroplasty (TKA) utilization it may be appreciated that the characteristics and usage patterns of joint replacement vary considerably as a function of time. The temporal dimension greatly complicates comparisons among registries, which were established at different time periods and contain varying follow up. Thus, in the evaluation of clinical failure modes and their relationship to biomaterials across and between different registries, appreciation of the temporal variable is important. If the long-term goal of a registry program is to improve the overall process of joint arthroplasty, tracking hospitalization outcomes (revisions, complications) is but the starting point
Yearly incidence of knee arthroplasty (100 000) 140 120
Females Males
100 80 60 40 20 0 1975 1980 1985 1990 1995 2000 2005 Year of operation
Copyright © 2009 SKAR
registry is compelling due to the anticipated future demand for joint arthroplasty. In the absence of a validated joint registry, administrative health care data in the United States represent a crucial resource in understanding the current and projected utilization of hip and knee replacements. The purpose of this chapter is to provide a comprehensive review of the utilization of joint replacements and to discuss the implications of the future demand for surgeries in the field of biomaterials. As they are the earliest source of utilization data for joint replacement, international joint registries and validated administrative databases are first summarized and compared. The projected demand for joint replacements between 2010 and 2030 is also addressed. Finally, we review the limitations of the projection techniques and outline the economic implications of an escalating demand for joint replacement surgery in the future.
Figure 1 Annual incidence of knee arthroplasty in Sweden per 100 000 persons. Source: Swedish Knee Arthroplasty Register, Lund, Sweden.
for tracking the contribution joint arthroplasty makes to society. In its first 22 years of operation the Swedish hip registry focused on clinical metrics of surgery outcomes. However, since 2001, this registry has placed increasing emphasis on documenting improvement of the patients’ quality of life following the surgery as well as the societal cost of performing the procedure. In many countries with a socialized health care system, including Sweden and Canada, the waiting time for surgery can be substantial. In Sweden, the mean wait time for total hip arthroplasty (THA) surgery was 312 days in 2007, whereas in Canada, the mean wait time was 182 days for THA. According to an economic analysis conducted by the Swedish hip registry, the societal cost for 1 year of wait time, incorporating lost productivity, is equivalent to the inpatient procedure cost of the surgery itself. Thus, the data from hip registries may be developed to drive changes in health care policy (e.g., reducing wait times in Sweden and Canada). Differences in health care delivery and access to joint replacement surgery cause wide variations in THA access between countries, as well as within countries over time. For example, within a country shifts in policy toward reducing wait times may increase the rate at which surgery is performed, even for a pool of patients that is not rapidly changing. Thus, policy shifts are but one example of the need for care
Current and Projected Utilization of Total Joint Replacements
in extrapolating the current and projected utilization of hip and knee surgery outside of its national health care system. Registries represent an important tool to evaluate the current use of total joint replacements in various countries, but they are by no means the only source of data regarding the utilization of surgical procedures. Large countries such as Germany and the United States currently do not have an operating hip and knee registry. Nationally representative administrative databases of countries without an operational registry are covered in the following section of this chapter. These databases can provide valuable and otherwise unavailable data regarding the current use of total hip and knee arthroplasty in the absence of a formal registry.
6.601.3. Public Data Sources for Orthopedic Implant Utilization in the United States Even in countries with an established registry, administrative databases represent an important data source for total joint replacements. An administrative database may comprise a sampling of electronic hospital discharge records, or in the case of Medicare, the entire insurance claim history for individual patients. Total hip and knee procedures are identified in these databases according to the codes from the 9th Revision of the International Classification of Diseases, Clinical Modification (ICD-9-CM; see Table 2). Three public sources of administrative claims data for the United States are summarized in the following subsections.
6.601.3.1. National Hospital Discharge Survey The National Hospital Discharge Survey (NHDS)3 is an annual survey conducted by the National Center for Health Statistics (NCHS). Started in 1965, this survey program has continuously Table 2
3
compiled a statistically representative sample of hospitalization from non-Federal and non-military short-stay community hospitals throughout the United States. As such, it is the oldest and most well-established inpatient discharge database in the country. Over the past decade, the number of hospitals included in NHDS has ranged from 430 to 490, with 300 000 discharge records sampled per year. Information collected by NHDS includes patient demographics (e.g., age, gender), disease diagnosis, type of procedure performed, institutional characteristics, and resource utilization. Based on the information collected by the survey, national and regional estimates of characteristics of patients and surgical and nonsurgical procedures in hospitals of various bed sizes and types of ownership can be estimated using the provided sampling weights.
6.601.3.2. Nationwide Inpatient Sample The Nationwide Inpatient Sample (NIS) is a larger and more recent database of inpatient discharge data in comparison with the NHDS.4 Established in 1988 by the Healthcare Cost & Utilization Project (HCUP) of the Agency of Healthcare Quality and Research (AHRQ), the NIS has a far larger sample size in terms of both discharge records and number of hospitals. Compared to the NHDS, the NIS has 25 times more records with 5–8 million records per year and also includes twice the number of hospitals. The sampling of NIS captures 20% of inpatient hospital visits each year in the United States, and thus is well suited for studying national trends for rare diseases or for examining the epidemiology of diagnoses or procedures within minority subpopulations. The NIS also captures patient, payer, and hospitalization factors, as well as charges and cost information for the hospitalization, which can be used to evaluate the economic impact of procedures and diagnoses.
Summary of ICD-9-CM codes for primary and revision total hip and knee replacement procedures
ICD9-CM-Code
Description
Comments
81.51 81.52
Primary total hip replacement Partial hip replacement
81.53 81.54
Revision of hip replacement, not otherwise specified Primary total knee replacement
The type of bearing surface is coded, if known (00.74–0.77) This includes unipolar and bipolar hip prostheses; the type of bearing surface is coded, if known (00.74–0.77) The type of bearing surface is coded, if known (00.74–0.77) This code includes bicompartmental, tricompartmental, and unicondylar knee arthroplasty
81.55 00.70
Revision of knee replacement, not otherwise specified Revision of hip replacement, both acetabular and femoral components Revision of hip replacement, acetabular component Revision of hip replacement, femoral component Revision of hip replacement, acetabular liner and/or femoral head only Hip bearing surface, metal-on-polyethylene Hip bearing surface, metal-on-metal Hip bearing surface, ceramic-on-ceramic Hip bearing surface, ceramic-on-polyethylene Revision of knee replacement, total (all components) Revision of knee replacement, tibial component Revision of knee replacement, femoral component Revision of knee replacement, patellar component Revision of total knee replacement, tibial insert (liner)
00.71 00.72 00.73 00.74 00.75 00.76 00.77 00.80 00.81 00.82 00.83 00.84
Introduced 1 October 2005 Introduced 1 October 2005 Introduced 1 October 2005 Introduced 1 October 2005 Introduced 1 October 2005 Introduced 1 October 2005 Introduced 1 October 2005 Introduced 1 October 2006 Introduced 1 October 2005 Introduced 1 October 2005 Introduced 1 October 2005 Introduced 1 October 2005 Introduced 1 October 2005
4
Orthopedic Surgery – Joint Replacement
6.601.3.3. Medicare The 5% Medicare so-called Limited Data Set (LDS) is available from the Center for Medicare and Medicaid Services (CMS). The complete 5% dataset consists of seven components: hospital inpatient, hospital outpatient, home health agency, skilled nursing facility, hospice care, physician carrier (Part B), and durable medical equipment. A denominator file is also available that tracks the date of death or (more rarely) withdrawal by Medicare beneficiaries from the program. In the LDS, patients are uniquely identified by an encrypted Medicare beneficiary identification number that remains consistent across all parts of the database as well as over time. In this way, the utilization of healthcare resources by a patient can be tracked in different health care settings (i.e., both inpatient and outpatient), as well as in home hospice care, and during physician office visits.
6.601.4. Current Utilization of Total Joint Replacements The number and prevalence of primary hip and knee replacement procedures have increased substantially in the United States between 1993 and 2006, most notably for primary TKA
(Figure 2). The number of primary TKA and primary THA increased by 148% and 66%, respectively, during this period, corresponding to compound annual growth rates of 7.2% and 4.0%. The number of revision TKA and THA grew by 142% and 29%, respectively, with corresponding compound annual growth rates of 7.0% and 2.0%. Even after adjusting for population changes, the increase in procedure rates since 1993 was also evident, along with the slowdown in the prevalence of primary and revision THA and primary TKA between 2005 and 2006 (Figure 3). To normalize the incidence of revision surgery, previous researchers from the Scandinavian registries have introduced the concept of a national revision burden, which is the ratio of revisions performed in a year to the total number of procedures (primary þ revision). Using the 1993–2006 NIS dataset, the US mean revision burden of 16.2% (range 13.9–17.8%) for THA was approximately twice that for TKA (7.9%; range 7.3–8.4%; see Tables 3 and 4). The greater revision burden for THA compared to TKA is consistent with the relative revision burden in Canada which is 2.1 times greater than primary6 and Finland which is 2.2 times greater.7 The US mean revision burden for THA is also 65% greater than for TKA in Australia8 and 78% greater than for Norway.9
600 000
Procedures
500 000
Primary THA Primary TKA
400 000
300 000
200 000
100 000 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 Year 50 000 45 000
Revision THA Revision TKA
Procedures
40 000 35 000 30 000 25 000 20 000 15 000 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 Year Figure 2 Annual number of primary (top panel) and revision (bottom panel) total hip arthroplasty and total knee arthroplasty in the United States. Note difference in y-axis scales.
Current and Projected Utilization of Total Joint Replacements
5
200
Procedure rates (per 100 000 persons)
175 150
Primary THA Primary TKA
125 100 75 50 25 0 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 Year
Procedure rates (per 100 000 persons)
25 20
Revision THA Revision TKA
15 10 5 0 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 Year
Figure 3 Annual incidence of primary (top panel) and revision (bottom panel) total hip arthroplasty and total knee arthroplasty in the United States per 100 000 persons.
Table 3
Mean revision burden for THA
Country
Period
Revision burden (%)
Reference
United States Australia Canada Finland Norway Sweden
1993–2006 2003–2007 2002–2006 1997–2006 1993–2007 2003–2007
16.2 15.7 12.4 17.3 14.6 10.1
Nationwide Inpatient Sample Australian Orthopaedic Association – National Joint Replacement Registry Canadian Institute for Health Information National Agency for Medicines The Norwegian Arthroplasty Register Swedish Hip Arthroplasty Register
Table 4
Mean revision burden for TKA
Country
Period
Revision burden (%)
Source
United States Australia Canada Finland Norway Sweden
1993–2006 2003–2007 2002–2006 1997–2006 1993–2007 1991–2003
7.9 9.5 6.1 7.9 8.2 4–7
Nationwide Inpatient Sample Australian Orthopaedic Association – National Joint Replacement Registry Canadian Institute for Health Information National Agency for Medicine Norwegian Arthroplasty Register Robertsson5
Overall, the THA revision burden in the United States is comparable to Australia8 and Finland7 (Table 3). Compared to the United States, the mean revision burden in Norway,9 Canada,6 and Sweden10 are all lower. For TKA (Table 4), the
US mean revision burden is comparable with the revision burdens of Norway9 and Finland.7 Compared to the United States, the knee revision burden is slightly lower in Canada6 and in Sweden,5 and slightly higher in Australia.8
6
Orthopedic Surgery – Joint Replacement
In addition to revision procedures, the level of specificity in the ICD-9-CM codes makes it possible to perform national epidemiologic studies of postoperative complications in the US population. In a study by Kurtz et al.,11 of periprosthetic infection between 1990 and 2004, the incidence of infection for both hip and knee arthroplasties in the United States nearly doubled from about 0.6% to 1.2%. The odds of infection increased annually at a rate of 5% (odds ratio: 1.049; 95% confidence intervals (CI): 1.04–1.06). The length of stay (LOS) for infected TJAs was close to twice as long as for uninfected TJAs (2.21 times longer for THA, 95% CI: 2.18–2.23 times longer; and 1.87 times longer for TKA, 95% CI: 1.85–1.88 times longer) (p < 0.0001 for both). Furthermore, the ratio in LOS between infected and uninfected TJA has been on a widening trend between 1990 and 2004, with a rate of increase at 1.15% from year to year. The corresponding charge ratio for infected TJAs was also significantly greater (p < 0.001). This study highlighted an increasing trend of infected hip and knee arthroplasties in the United States. As demonstrated by the greater LOS and hospitalization charges/costs for infected TJA in this study and others,12 the economic impact of deep infection is substantial. This infection research illustrates how administrative data from the NIS can be effectively used to quantify the national burden of specific total joint arthroplasty (TJA) complications, in addition to revision. Recently, additional specificity provided in the ICD-9-CM procedure and diagnosis codes has greatly strengthened administrative databases as tools to examine national trends of TJA failure modes and revision strategies. In October 2005, based on a request from a group of orthopedic and health services researchers, the CMS and the NCHS implemented a series of changes to the ICD-9-CM diagnosis and procedure codes13 (Table 2). These changes included new procedure codes that specify the THA bearing type, as well as new diagnosis and procedure codes to specify the cause of failure (e.g., dislocation, loosening, etc.) and type of component revised (e.g., acetabular component only, femoral component only, etc.) for revision THA. The availability of new bearing surface codes, revision diagnosis codes, and revision procedure codes provides an unprecedented opportunity to evaluate the comparative effectiveness of Total hip replacement (THR) bearing surfaces using administrative data. Based on the new revision diagnosis and procedure codes, the epidemiology of revision THA was evaluated using the NIS database.14 Based on a sample of 51 345 revision THA procedures spanning 1.25 years from October 2005 to December 2006, instability/dislocation was the most commonly reported cause of revision THA (22.5%), followed by mechanical loosening (19.7%) and infection (14.8%). All component revisions were most frequently reported (41.1%), followed by femoral component revision (13.2%), acetabular component revision (12.7%), isolated femoral head and acetabular liner exchange (12.6%), and arthrotomy (9.1%). Despite the increasing adoption of large diameter heads for THA over the recent years, this analysis indicated that dislocation remains the primary diagnosis reported for revision THA. In summary, it can be seen that, based on data from administrative databases and national total joint registries, the current utilization of total joint replacements has been
increasing over time. Despite the recognized success of these procedures, the number of revision procedures continues to increase for both THA and TKA. Minimizing revisions and complications continues to be a clinical concern and a major financial need.
6.601.5. Projected Utilization of Total Joint Replacements Projections are important for guiding health care policy. In 2002, the American academy of orthopedic surgeons (AAOS) published projections of primary total hip and total knee replacement surgery through 2030, based on surgery rates calculated from the 1996 to 1999 hospitalization data from the NHDS and US Census projections for the next 30 years.15 It is now clear that these projections by the AAOS underpredicted the expected utilization of primary TJA because the estimates of the surgery rates assumed a constant prevalence based on the average rate over the 4 years of the 1996–99 NHDS dataset and did not account for any year-to-year change in the rate itself. Thus, the projected growth in the number of hip and knee replacements in the AAOS model was fueled solely by the anticipated growth of the US population and was also limited to primary TJA without consideration for revision procedures. Since revision procedures place extensive additional demands on hospitals and surgeons and on medical costs, these should be considered in an analysis of projected future rates and population-based costs of arthroplasty procedures to the US health care system. Motivated by the limitations in the prior projections, the authors used a much larger data source in the form of the NIS data, which has 25 times more discharge records than the NHDS.16,17 These projections16 were based on 1990–2003 NIS data and the historical trajectory of surgery rates. They estimated the demand for primary THA to grow by 174%, from 208 600 in 2005 to 572 000 by 2030. The demand for primary TKA was also projected to grow more than sixfold, from 450 000 (95% prediction interval: 425 000–477 000) in 2005 to 3.48 million procedures (95% prediction interval: 2.95–4.14 million) by 2030. Revision TJA were also estimated to grow substantially from 40 800 to 96 700 for THA (an increase of 137%) and from 38 300 to 268 200 for TKA (an increase of 601%) between 2005 and 2030. Following these initial projections, three additional years of NIS data (2004–2006) became available, allowing the comparison of previous projections with the recent NIS data, updating of the previous projections, and further demographic analysis of the projections. The previous projections16 provided reasonably accurate estimates of the primary and revision TJA trends between 2004 and 2006,17 particularly for revision TJA procedures, which were within the 95% CI of the previous projections. However, the previous projections underestimated the historical number of primary TJA procedures. Based on the additional 2004–2006 NIS data, the projections were reanalyzed, incorporating a ‘variable rate’ and a ‘constant rate’ approach to provide upper and lower prediction bounds, respectively. The ‘variable rate’ approach was consistent with the previous analysis, which allowed both the population and prevalence of surgery to vary over time. Conversely, the
Current and Projected Utilization of Total Joint Replacements
7
4500
Procedures (⫻1000)
4000 3500
Primary THA Primary TKA
3000 2500 2000 1500 1000 500 0 2010
2015
2020
2025
2030
2025
2030
Year 450
Procedures (⫻1000)
400 350
Revision THA Revision TKA
300 250 200 150 100 50 0 2010
2015
2020 Year
Figure 4 Projected annual demand for primary (top panel) and revision (bottom panel) total hip arthroplasty and total knee arthroplasty in the United States through the year 2030.
‘constant rate’ approach allowed the population to vary over time, but assumed that the future prevalence of surgery was constant, which was based on the average rate between 2004 and 2006. Based on the updated projections,17 the number of primary THA was predicted to increase from 229 900 procedures in 2006 to between 345 700 (constant rate) and 891 800 (variable rate) procedures in 2030 (Figure 4). Primary TKA was also predicted to increase from 524 600 procedures to between 792 200 (constant rate) and 4.34 million (variable rate) procedures over the same time period (Figure 4). Due to the relatively stable historical revision burden rates, the predicted demand for revision TJA is expected to be driven primarily by the increase in demand for primary procedures. Revision THA and TKA were projected to increase from 37 200 and 46 400 to 59 000 (constant rate)–91 400 (variable rate) and 64 600 (constant rate)–339 000 (variable rate), respectively, between 2006 and 2030. If the trajectory of surgery prevalence were to continue into the future, the demand for primary THA and TKA among younger patients, that is, patients <65 years old, will be projected to exceed 50% of all THA and TKA patients by 2011 and 2016, respectively. Younger patients will also be projected to exceed 50% of the revision TKA patient population by 2011. By 2030, the demand for TJA by younger patients aged <65 years will comprise 52% of primary THAs and 55–62% of primary or revision TKAs.
Based on the projected demand for primary and revision TJA, the corresponding economic impact in terms of hospitalization cost was also computed. By using the costto-charge ratio files provided in the NIS dataset to convert hospitalization charges to costs, the historical changes in average procedure costs were then projected for 2030. By combining the projected number of procedures and the projected costs for each procedure, the overall cost projections for primary and revision TJA were estimated. If the historical growth trajectory of procedure demand and costs continues, the overall cost for primary THA and TKA were projected to increase from $3.5 to $25.1 billion (95% CI: $14.9–40.4 billion) and from $7.0 to $92.9 billion (95% CI: $58.8–$144.6 billion), respectively (Figure 5). The economic burden for revision THA and TKA was also projected to increase from $712 million to $2.9 billion (95% CI: $1.1–$5.8 billion) and from $718 million to $13.9 billion (95% CI: $6.6–$27.1 billion), respectively.
6.601.6.
Summary
In summary, the analyses of current and projected utilization for joint arthroplasty predict a massive anticipated demand for these procedures in the coming decades. However, the current economic and regulatory climate for health care
8
Orthopedic Surgery – Joint Replacement
Total cost ($ million)
150 000 Primary THA Primary TKA 100 000
50 000
0 2010
2015
2020 Year
2025
2030
2020 Year
2025
2030
30 000
Total cost ($ million)
25 000
Revision THA Revision TKA
20 000 15 000 10 000 5000 0 2010
2015
Figure 5 Projected annual cost of primary (top panel) and revision (bottom panel) total hip arthroplasty and total knee arthroplasty in the United States through the year 2030.
innovation is more challenging than ever before. New biomaterials for total joint replacement must be engineered to reduce widely recognized current complications such as loosening, dislocation, and infection for existing patient populations and to provide new functional capabilities to younger and more active patients. Technologies that only provide improved outcomes at 10þ years of service will require increased health economic justification. As scientists develop new biomaterials for the future joint replacement market, it is essential for commercial success that the studies to prove the cost effectiveness of these new technologies be designed and fully appreciated at the onset of the research and development phase in the product lifecycle.
References 1. Kurtz, S.; Mowat, F.; Ong, K.; Chan, N.; Lau, E.; Halpern, M. J. Bone Joint Surg. Am. 2005, 87, 1487–1497. 2. Malchau, H.; Herberts, P.; Ahnfelt, L. Acta Orthop. Scand. 1993, 64, 497–506. 3. National Center for Health Statistics. National Hospital Discharge Survey Description, 2009. 4. Agency for Healthcare Research and Quality. HCUP Databases. Healthcare Cost and Utilization Project (HCUP), 2008.
5. Robertsson, O. J. Bone Joint Surg. Br. 2007, 89, 1–4. 6. Canadian Institute for Health Information. Canadian Joint Replacement Registry (CJRR). 2007 Annual Report – Hip and Total Knee Replacements in Canada, 2008. 7. National Agency for Medicines. The 2006 Implant Yearbook on Orthopaedic Endoprostheses: Finnish Arthroplasty Register, 2008. 8. Australian Orthopaedic Association – National Joint Replacement Registry. Hip and knee arthroplasty, Annual report 2008. 9. The Norwegian Arthroplasty Register. Report 2008. 10. Swedish Hip Arthroplasty Register. Swedish Hip Arthroplasty Register, Annual Report 2007, 2008. 11. Kurtz, S. M.; Lau, E.; Schmier, J.; Ong, K. L.; Zhao, K.; Parvizi, J. J. Arthroplasty 2008, 23(7), 984–991. 12. Bozic, K. J.; Ries, M. D. J. Bone Joint Surg. Am. 2005, 87, 1746–1751. 13. Bozic, K. J.; Katz, P. P.; Showstack, J. A.; et al. The use of clinical and economic outcomes data to influence health policy in the United States: The case of total joint replacement, OREF Clinical Outcomes Research Award Paper. Presented at the 73rd Annual Meeting of the American Academy of Orthopaedic Surgeons, Chicago, IL, 2006. 14. Bozic, K. J.; Kurtz, S. M.; Lau, E.; Ong, K.; Vail, T. P.; Berry, D. J. J. Bone Joint Surg. Am. 2009, 91, 128–133. 15. Frankowski, J. J.; Watkins-Castillo, S. Primary Total Knee and Hip arthroplasty Projections for the US Population to the Year 2030, 2002. 16. Kurtz, S.; Ong, K.; Lau, E.; Mowat, F.; Halpern, M. J. Bone Joint Surg. Am. 2007, 89, 780–785. 17. Kurtz, S. M.; Lau, E.; Ong, K.; Zhao, K.; Kelly, M.; Bozic, K. J. Clin. Orthop. Relat. Res. 2009, 467(10), 2606–2612 [Epub Apr 10].
Current and Projected Utilization of Total Joint Replacements
Relevant Websites http://www.shpr.se/ – Swedish Hip Arthroplasty Register. http://www.knee.nko.se/ – Swedish Knee Arthroplasty Register. http://www.haukeland.no/nrl/ – The Norwegian Arthroplasty Register. http://www.dmac.adelaide.edu.au/aoanjrr/ – The National Joint Replacement Registry (Australia).
http://www.cdhb.govt.nz/NJR/ – National Joint Register (New Zealand). http://www.njrcentre.org.uk/ – National Joint Registry (UK). http://www.cdc.gov/nchs/nhds.htm – National Hospital Discharge Survey (USA). http://www.hcup-us.ahrq.gov/nisoverview.jsp – Overview of the Nationwide Inpatient Sample (NIS). http://www.cms.hhs.gov/LimitedDataSets/ – Centers for Medicare & Medicaid Services.
9