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What Is the Right Rate for Total Hip Arthroplasty?
Editori I What Is the Right Rate for Total Hip Arthroplasty? Since its introduction in 1962, total hip arthroplasty has evolved into standard therapy for advanced arthritis of the hip. More than 120,000 procedures are performed annually in North America at a direct cost in excess of $20,000 per case and $2.5 billion per year.' As health-care costs spiral upward in the United States, improving efficiency, maintaining quality, and eliminating barriers to care for the medically indigent loom as major challenges for the nation. Rational planning for available personnel and health services necessitates accurate estimates of the potential need for expensive procedures such as hip arthroplasty. Estimation of Need.-Estimating potential "need" is conceptually and methodologically complex. Assessment of needs has generally been approached by calculating resource utilization, which is governed by patient demand. This technique is credible only in settings where demand and 'need are likely to be similar-that is, where patients have virtually complete access to health care and providers receive no financial incentives to deliver more services than necessary. Olmsted County, Minnesota, fulfills these criteria and has proved invaluable for estimating the need for various medical services.' In this tradition, Madhok and associates report in this issue of the Mayo Clinic Proceedings (pages 11 to 18) that the age-adjusted rate of total hip replacement in Olmsted County has increased gradually during the past decade to approximately 60 operations per 100,000 person-years, and they suggest that these data might be used to estimate the national requirement for total hip replacement. Assessment of Current Study.- The study by Madhok and colleagues is well done, but several limitations should be noted. First, elderly patients with arthritis may move from Minnesota to warmer climates and ultimately undergo hip arthroplasty elsewhere. If selective emigration of patients with advanced arthritis of the hip occurs, Olmsted County data would underestimate the actual need for surgical treatment of this condition. Second, generalizing surgical rates
This work was supported in part by Grant AR 36308 from the National Institutes of Health, Public Health Service, and a postdoctoral fellowship (J.N.K.) from the Arthritis Foundation. Address reprint requests to Dr. J. N. Katz, Department of Rheumatology/Immunology, Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115. Mayo Clin Proc 1993; 68:86-87
from a single geographic region can be inaccurate. Substantial (1.5- to 2-fold) regional variations have been noted in the rates of total hip replacement and other procedures.v' These variations in surgical rates are not explained by appropriateness of established clinical indications," availability of health care," or system of reimbursement." Rather, regional variations seem to reflect differences of opinion among physicians (and perhaps their patients) about the appropriateness of surgical intervention, which cannot be resolved with the limited data currently available." Because many of the clinicians in Olmsted County were trained at the same institution (Mayo Clinic), that geographic area may be particularly vulnerable to the influence of local practice style and therefore may have atypical rather than representative surgical rates. Finally, the analysis would be clearer if hip fracture were considered separately from elective arthroplasty because the indications for surgical treatment of these two conditions differ. These caveats aside, the data are probably the best available estimates of the need for total hip arthroplasty in the United States. It is reassuring, then, that the data from Olmsted County are in agreement with recent national estimates of hip replacement utilization-or is it? This study prompts us to reexamine current approaches to assessment of needs and to propose alternative strategies. Extent of Clinical Benefit.-"Need" for an elective operative procedure is relative, not absolute. If we assume that resources available to maintain and improve the health of the nation are limited-an assumption that has not guided policy in the past but increasingly will in the future-every dollar spent on hip arthroplasty is no longer available for other health services. Therefore, determining the appropriate rate of total hip arthroplasty involves both estimating the number of patients who would benefit substantially from surgical treatment and deciding how much of the (theoretically) fixed health-care budget to allocate for improvement of the wellbeing of patients with advanced arthritis of the hip. The number of patients who would benefit can be estimated empirically. Patients with the greatest preoperative functional impairment have the most clinical improvement after hip replacement." Therefore, the primary clinical indications for hip arthroplasty are severe pain and functional loss, not radiographic damage and limited range of motion (which correlate loosely with symptoms and function, respectively).' The number ofpatients who may have appropriate indications for hip arthroplasty can be estimated with use of arthritis prevalence surveys that incorporate evaluation of musculoskeletal function. Clinical indications can be 86
© 1993 Mayo Foundation/or Medical Education and Research
Mayo Clin Proc, January 1993, Vol 68
further refined by considering other factors that affect surgical outcome. For example, an increased number of comorbid conditions is associated with a higher risk of perioperative complications and less functional improvement, 1.9 and a greater level of physical activity and obesity are associated with a higher risk of loosening of the prosthesis. 1 Accounting for these and other prognostic variables'? would yield a more precise assessment of the number of patients who would benefit clinically from total hip arthroplasty. Preferences and Expectations of Patients.-Patients with similar clinical indications may value relief of pain or increased physical function differently. For example, patients with arthritis of the hip who engage in physically demanding occupations or activities may report greater benefit and satisfaction postoperatively than more sedentary patients. In order to optimize patient satisfaction and wellbeing after surgical therapy, the patient's expectations and values must be incorporated into the decision of whether to proceed with such treatment." Access to Arthroplasty.-Finally, patients with appropriate clinical indications may not have access to arthroplasty. Barriers include paucity of appropriately trained surgeons in rural or inner-city areas and lack of health insurance (in those younger than 65 years of age) to pay for the procedure 'and the associated rehabilitation. In addition, subtle biases in the health-care system may preclude patients from obtaining a referral or a recommendation for surgical treatment because of age, race, or gender. Until universal access to health services is ensured, utilization data on total hip arthroplasty may actually underestimate the need for this procedure. Conclusion-s-The foregoing discussion has clear implications for research and health policy. First, assessment of need for total hip arthroplasty should begin with data that link prevalence of arthritis of the hip to functional limitations. Second, additional research is needed to identify prognostically important variables that modify the extent of clinical benefit. Third, physicians and patients should discuss explicitly the expectations and priorities of the patient so that satisfaction with the surgical result will be optimized. Decision balance sheets 12 or interactive video-disk technology" may be useful in this effort. Finally, estimating the number of Americans who would benefit from total hip arthroplasty, providing them access to the procedure, and effectively restricting surgical treatment to patients who would benefit substantially present ethical and political problems of considerable magnitude. Americans must embrace universal access to health care and continue to move-however glacially-toward consensus on the cost we are willing to bear to improve the well-being of our citizens.
EDITORIAL
87
Acknowledgment.-We thank Drs. David Bates and John Esdaile for comments on a preliminary draft of this editorial. Jeffrey N. Katz, M.D., M.S. Department of Rheumatology/Immunology Matthew H. Liang, M.D., M.P.H. Departments of Rheumatology/Immunology and Medicine Brigham and Women's Hospital Boston, Massachusetts
REFERENCES 1.
2.
3. 4.
5.
6. 7.
8.
9.
10.
11.
12. 13.
Harris WH, Sledge CB. Total hip and total knee replacement (first of two parts). N Engl J Med 1990; 323 :725-731 Reiman AS. Determining how much medical care we need [editorial]. N Engl J Med 1980; 303:1292-1293 Wennberg IE, Freeman JL, Culp WJ. Are hospital services rationed in New Haven or over-utilised in Boston? Lancet 1987; 1:1185-1188 Keller RB, Soule DN, Wennberg IE, Hanley DF. Dealing with geographic variations in the use of hospitals: the experience of the Maine Medical Association Foundation orthopaedic study group. J Bone Joint Surg [Am] 1990; 72:1286-1293 Chassin MR, Kosecoff J, Park RE, Winslow CM, Kahn KL, Merrick NJ, et al. Does inappropriate use explain geographic variations in the use of health care services? A study of three procedures. JAMA 1987; 258:2533-2537 Wennberg JE. The paradox of appropriate care [editorial]. JAMA 1987; 258:2568-2569 McPherson K, Wennberg IE, Hovind OB, Clifford P. Smallarea variations in the use of common surgical procedures: an international comparison of New England, England, and Norway. N Engl J Med 1982; 307:1310-1314 Liang MH, Cullen KE, Larson MG, Thompson MS, Schwartz JA, Fossel AH, et al. Cost-effectiveness of total joint arthroplasty for osteoarthritis. Arthritis Rheum 1986; 29:937-943 Cleary PD, Greenfield S, Mulley AG, Pauker SG, Schroeder SA, Wexler L,et al. Variations in length of stay and outcomes for six medical and surgical conditions in Massachusetts and California. JAMA 1991; 266:73-79 Liang MH, Katz IN, Phillips C, Sledge C, Cats-Baril W, American Academy of Orthopaedic Surgeons Task Force on Outcome Studies. The total hip arthroplasty outcome evaluation form of the American Academy of Orthopaedic Surgeons: results of a nominal group process. J Bone Joint Surg [Am] 1991; 73:639-646 Barry MJ, Mulley AG Jr, Fowler FJ, Wennberg IE. Watchful waiting vs immediate transurethral resection for symptomatic prostatism: the importance of patients' preferences. JAMA 1988; 259:3010-3017 Eddy DM. Comparing benefits and harms: the balance sheet. JAMA 1990; 263:2493, 2498, 2501, 2505 Wolinsky H. TV, medicine meet as interactive videodisks engage patients, ACP Observer 1992 Jun; 12:7
This work was supported in part by Grant AR 36308 from the National Institutes of Health, Public Health Service, and a postdoctoral fellowship (J.N.K.) from the Arthritis Foundation. Address reprint requests to Dr. J. N. Katz, Department of Rheumatology/Immunology, Brigham and Women's Hospital, 75 Francis Street, Boston, MA 02115. Mayo Clin Proc 1993; 68:86-87
from a single geographic region can be inaccurate. Substantial (1.5- to 2-fold) regional variations have been noted in the rates of total hip replacement and other procedures.v' These variations in surgical rates are not explained by appropriateness of established clinical indications," availability of health care," or system of reimbursement." Rather, regional variations seem to reflect differences of opinion among physicians (and perhaps their patients) about the appropriateness of surgical intervention, which cannot be resolved with the limited data currently available." Because many of the clinicians in Olmsted County were trained at the same institution (Mayo Clinic), that geographic area may be particularly vulnerable to the influence of local practice style and therefore may have atypical rather than representative surgical rates. Finally, the analysis would be clearer if hip fracture were considered separately from elective arthroplasty because the indications for surgical treatment of these two conditions differ. These caveats aside, the data are probably the best available estimates of the need for total hip arthroplasty in the United States. It is reassuring, then, that the data from Olmsted County are in agreement with recent national estimates of hip replacement utilization-or is it? This study prompts us to reexamine current approaches to assessment of needs and to propose alternative strategies. Extent of Clinical Benefit.-"Need" for an elective operative procedure is relative, not absolute. If we assume that resources available to maintain and improve the health of the nation are limited-an assumption that has not guided policy in the past but increasingly will in the future-every dollar spent on hip arthroplasty is no longer available for other health services. Therefore, determining the appropriate rate of total hip arthroplasty involves both estimating the number of patients who would benefit substantially from surgical treatment and deciding how much of the (theoretically) fixed health-care budget to allocate for improvement of the wellbeing of patients with advanced arthritis of the hip. The number of patients who would benefit can be estimated empirically. Patients with the greatest preoperative functional impairment have the most clinical improvement after hip replacement." Therefore, the primary clinical indications for hip arthroplasty are severe pain and functional loss, not radiographic damage and limited range of motion (which correlate loosely with symptoms and function, respectively).' The number ofpatients who may have appropriate indications for hip arthroplasty can be estimated with use of arthritis prevalence surveys that incorporate evaluation of musculoskeletal function. Clinical indications can be 86
© 1993 Mayo Foundation/or Medical Education and Research
Mayo Clin Proc, January 1993, Vol 68
further refined by considering other factors that affect surgical outcome. For example, an increased number of comorbid conditions is associated with a higher risk of perioperative complications and less functional improvement, 1.9 and a greater level of physical activity and obesity are associated with a higher risk of loosening of the prosthesis. 1 Accounting for these and other prognostic variables'? would yield a more precise assessment of the number of patients who would benefit clinically from total hip arthroplasty. Preferences and Expectations of Patients.-Patients with similar clinical indications may value relief of pain or increased physical function differently. For example, patients with arthritis of the hip who engage in physically demanding occupations or activities may report greater benefit and satisfaction postoperatively than more sedentary patients. In order to optimize patient satisfaction and wellbeing after surgical therapy, the patient's expectations and values must be incorporated into the decision of whether to proceed with such treatment." Access to Arthroplasty.-Finally, patients with appropriate clinical indications may not have access to arthroplasty. Barriers include paucity of appropriately trained surgeons in rural or inner-city areas and lack of health insurance (in those younger than 65 years of age) to pay for the procedure 'and the associated rehabilitation. In addition, subtle biases in the health-care system may preclude patients from obtaining a referral or a recommendation for surgical treatment because of age, race, or gender. Until universal access to health services is ensured, utilization data on total hip arthroplasty may actually underestimate the need for this procedure. Conclusion-s-The foregoing discussion has clear implications for research and health policy. First, assessment of need for total hip arthroplasty should begin with data that link prevalence of arthritis of the hip to functional limitations. Second, additional research is needed to identify prognostically important variables that modify the extent of clinical benefit. Third, physicians and patients should discuss explicitly the expectations and priorities of the patient so that satisfaction with the surgical result will be optimized. Decision balance sheets 12 or interactive video-disk technology" may be useful in this effort. Finally, estimating the number of Americans who would benefit from total hip arthroplasty, providing them access to the procedure, and effectively restricting surgical treatment to patients who would benefit substantially present ethical and political problems of considerable magnitude. Americans must embrace universal access to health care and continue to move-however glacially-toward consensus on the cost we are willing to bear to improve the well-being of our citizens.
EDITORIAL
87
Acknowledgment.-We thank Drs. David Bates and John Esdaile for comments on a preliminary draft of this editorial. Jeffrey N. Katz, M.D., M.S. Department of Rheumatology/Immunology Matthew H. Liang, M.D., M.P.H. Departments of Rheumatology/Immunology and Medicine Brigham and Women's Hospital Boston, Massachusetts
REFERENCES 1.
2.
3. 4.
5.
6. 7.
8.
9.
10.
11.
12. 13.
Harris WH, Sledge CB. Total hip and total knee replacement (first of two parts). N Engl J Med 1990; 323 :725-731 Reiman AS. Determining how much medical care we need [editorial]. N Engl J Med 1980; 303:1292-1293 Wennberg IE, Freeman JL, Culp WJ. Are hospital services rationed in New Haven or over-utilised in Boston? Lancet 1987; 1:1185-1188 Keller RB, Soule DN, Wennberg IE, Hanley DF. Dealing with geographic variations in the use of hospitals: the experience of the Maine Medical Association Foundation orthopaedic study group. J Bone Joint Surg [Am] 1990; 72:1286-1293 Chassin MR, Kosecoff J, Park RE, Winslow CM, Kahn KL, Merrick NJ, et al. Does inappropriate use explain geographic variations in the use of health care services? A study of three procedures. JAMA 1987; 258:2533-2537 Wennberg JE. The paradox of appropriate care [editorial]. JAMA 1987; 258:2568-2569 McPherson K, Wennberg IE, Hovind OB, Clifford P. Smallarea variations in the use of common surgical procedures: an international comparison of New England, England, and Norway. N Engl J Med 1982; 307:1310-1314 Liang MH, Cullen KE, Larson MG, Thompson MS, Schwartz JA, Fossel AH, et al. Cost-effectiveness of total joint arthroplasty for osteoarthritis. Arthritis Rheum 1986; 29:937-943 Cleary PD, Greenfield S, Mulley AG, Pauker SG, Schroeder SA, Wexler L,et al. Variations in length of stay and outcomes for six medical and surgical conditions in Massachusetts and California. JAMA 1991; 266:73-79 Liang MH, Katz IN, Phillips C, Sledge C, Cats-Baril W, American Academy of Orthopaedic Surgeons Task Force on Outcome Studies. The total hip arthroplasty outcome evaluation form of the American Academy of Orthopaedic Surgeons: results of a nominal group process. J Bone Joint Surg [Am] 1991; 73:639-646 Barry MJ, Mulley AG Jr, Fowler FJ, Wennberg IE. Watchful waiting vs immediate transurethral resection for symptomatic prostatism: the importance of patients' preferences. JAMA 1988; 259:3010-3017 Eddy DM. Comparing benefits and harms: the balance sheet. JAMA 1990; 263:2493, 2498, 2501, 2505 Wolinsky H. TV, medicine meet as interactive videodisks engage patients, ACP Observer 1992 Jun; 12:7