The Journal of Bone & Joint Surgery

The Journal of Bone & Joint Surgery, Volume 89, Issue 3

Scientific Articles | March 01, 2007

Incidence and Short-Term Outcomes of Primary and Revision Hip Replacement in the United States

Chunliu Zhan, MD, PhD¹; Ronald Kaczmarek, MD, MPH²; Nilsa Loyo-Berrios, PhD²; Judith Sangl, PhD¹; Roselie A. Bright, ScD²

¹ Centers for Outcomes and Evidence (C.Z.) and Quality Improvement and Patient Safety (J.S.), Agency for Healthcare Research and Quality, 540 Gaither Road, Rockville, MD 20850. E-mail address for C. Zhan: chunliu.zhan@ahrq.hhs.gov. E-mail address for J. Sangl: judith.sangl@ahrq.hhs.gov
² Epidemiology Branch, Division of Postmarket Surveillance, Office of Surveillance and Biometrics, Center for Devices and Radiological Health, Food and Drug Administration, 1350 Piccard Drive, HFZ-541, Rockville, MD 20850. E-mail address for R. Kaczmarek: rxk@cdrh.fda.gov. E-mail address for N. Loyo-Berrios: nlb@cdrh.fda.gov. E-mail address for R.A. Bright: rxb@cdrh.fda.gov

View Disclosures and Other Information

Disclosure: The authors did not receive any outside funding or grants in support of their research for or preparation of this work. Neither they nor a member of their immediate families received payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, division, center, clinical practice, or other charitable or nonprofit organization with which the authors, or a member of their immediate families, are affiliated or associated.

No statement in this article should be construed as an official position of the Agency for Healthcare Research and Quality, the Food and Drug Administration, or the United States Department of Health and Human Services.

Investigation performed at the Agency for Healthcare Research and Quality, Rockville, Maryland

The Journal of Bone and Joint Surgery, Incorporated

J Bone Joint Surg Am, 2007 Mar 01;89(3):526-533. doi: 10.2106/JBJS.F.00952

5 Recommendations (Recommend) | 3 Comments | Saved by 3 Users Save Case

Article

Comments (0)

text A A A

Abstract

Background: The purpose of this study was to use 2003 nationwide United States data to determine the incidences of primary total hip replacement, partial hip replacement, and revision hip replacement and to assess the short-term patient outcomes and factors associated with the outcomes.

Methods: We screened more than eight million hospital discharge abstracts from the 2003 Healthcare Cost and Utilization Project Nationwide Inpatient Sample and approximately nine million discharge abstracts from five state inpatient databases. Patients who had undergone total, partial, or revision hip replacement were identified with use of International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) procedure codes. In-hospital mortality, perioperative complications, readmissions, and the association between these outcomes and certain patient and hospital variables were analyzed.

Results: Approximately 200,000 total hip replacements, 100,000 partial hip replacements, and 36,000 revision hip replacements were performed in the United States in 2003. Approximately 60% of the patients were sixty-five years of age or older and at least 75% had one or more comorbid diseases. The in-hospital mortality rates associated with these three procedures were 0.33%, 3.04%, and 0.84%, respectively. The perioperative complication rates associated with the three procedures were 0.68%, 1.36%, and 1.08%, respectively, for deep vein thrombosis or pulmonary embolism; 0.28%, 1.88%, and 1.27% for decubitus ulcer; and 0.05%, 0.06%, and 0.25% for postoperative infection. The rates of readmission, for any cause, within thirty days were 4.91%, 12.15%, and 8.48%, respectively, and the rates of readmissions, within thirty days, that resulted in a surgical procedure on the affected hip were 0.79%, 0.91%, and 1.53%. The rates of readmission, for any cause, within ninety days were 8.94%, 21.14%, and 15.72%, and the rates of readmissions, within ninety days, that resulted in a surgical procedure on the affected hip were 2.15%, 1.61%, and 3.99%. Advanced age and comorbid diseases were associated with worse outcomes, while private insurance coverage and planned admissions were associated with better outcomes. No consistent association between outcomes and hospital characteristics, such as hip procedure volume, was identified.

Conclusions: Total hip replacement, partial hip replacement, and revision hip replacement are associated with different rates of postoperative complications and readmissions. Advanced age, comorbidities, and nonelective admissions are associated with inferior outcomes.

Level of Evidence: Therapeutic Level III. See Instructions to Authors for a complete description of levels of evidence.

Figures in this Article

Total hip replacement, partial hip replacement, and revision hip replacement are among the most successful surgical procedures performed to improve quality of life¹. Authors of previous studies estimated that about five per 10,000 population underwent total hip replacement in Great Britain between 1976 and 1985² and in the United States between 1995 and 1999³. The rates are higher in the elderly and in patients with chronic conditions: twenty to ninety persons per 10,000 United States Medicare beneficiaries underwent total hip replacement in 1988⁴, and thirty-five per 10,000 patients undergoing dialysis had total hip replacement in the United States between 1995 and 1999³. Most previous studies have focused on only one of the three procedures and one or a few outcomes measures; thus, a comprehensive picture of hip replacement operations and patient outcomes does not exist.

Studies of patient outcomes following hip replacement procedures have primarily focused on mortality and complications. The mortality rates have been estimated to be between 0.15% and 2% during the inpatient hospital stay^2,5-8 and between 0.45% and 1.1% ninety days following total hip replacement^3,6,9,10, 2.4% thirty days following partial hip replacement¹¹, and between 0.87% and 2.6% ninety days following revision hip replacement^6-12. Perioperative thromboembolism is the most recognized complication of hip replacement^13-18, with an estimated rate of 1% during the inpatient hospital stay^12,19 and 2.27% more than ninety days following total hip replacement²⁰; the in-hospital rate of thromboembolism after revision hip replacement has been reported to be 1.8%²¹. Other recognized perioperative complications include infection^22-24, excessive bleeding, decubitus ulcer, and dislocation^19,25. Approximately 5% of patients treated with total hip replacement and 8% treated with revision hip replacement were readmitted to the hospital within ninety days after discharge¹².

The most important risk factors associated with adverse patient outcomes following hip procedures include advanced age and coexistent diseases²⁶ such as congestive heart failure, chronic renal failure, and diabetes mellitus²⁷. Most studies have shown better outcomes for patients treated by surgeons who perform a large volume of total hip replacements^28-32, and some studies have demonstrated a positive association between hospital volume and patient outcomes^28,30-34.

The specific aim of this study was to provide a comprehensive assessment of hip replacement procedures in the United States with use of the most recent, nationwide sample of claims or discharge abstracts as well as to examine all outcomes and risk variables ascertainable in hospital administrative data.

Materials and Methods

Data Sources and Variables

We used the 2003 Healthcare Cost and Utilization Project (HCUP) Nationwide Inpatient Sample (NIS) and selected state inpatient databases developed by the Agency for Healthcare Research and Quality (AHRQ)³⁵. The 2003 NIS file contains approximately eight million hospital discharge abstracts from 994 acute-care, general hospitals in thirty-seven states, approximating a 20% stratified sample of nonfederal hospitals in the United States. The NIS includes data on sources and types of admissions; diagnosis-related groups (DRGs); fifteen diagnosis codes as classified in the International Classification of Diseases, Ninth Edition, Clinical Modification (ICD-9-CM); fifteen ICD-9-CM procedure codes; number of days from admission to the procedure; discharge status; length of hospital stay; total charges; patient demographic characteristics; insurance coverage; and a few hospital characteristics (e.g., procedure volume, size, ownership, and location). The NIS also contains sampling weights to be used to generate national estimates and standard errors.

Currently, only a few states assign the encrypted patient identification in hospital discharge abstracts that is needed for assessing readmissions. A previous study examining readmissions of patients with diabetes with use of state inpatient databases revealed that five states (California, Missouri, New York, Tennessee, and Virginia) appeared to code encrypted patient identification accurately³⁶. State inpatient databases from these five states for 2003, which contain 100% of the approximately nine million discharges from 1074 hospitals, were combined for the readmissions analyses in the present study. The variables in the state inpatient databases are similar to those in the NIS.

Two additional variables, comorbidities and hospital volume, were created on the basis of variables contained in the NIS and state inpatient databases. The Elixhauser method³⁷ was used to define thirty comorbid diseases on the basis of ICD-9-CM codes. Comorbidities were further summarized into four categories: without any comorbidity, with one comorbidity, with two comorbidities, and with three or more comorbidities. On the basis of previous research²⁸, the number of elective total hip replacement procedures performed was determined for each hospital, and a hospital was categorized as "low-volume" if it performed one to ten elective total hip replacements and as "high-volume" if it performed 100 or more elective total hip replacements. Hip procedures were identified on the basis of ICD-9-CM procedure codes: 81.51 for total hip replacement, 81.52 for partial hip replacement, and 81.53 for revision hip replacement.

Patient Outcomes

Three groups of patient outcomes measures were analyzed. The first group included length of stay, total charges, in-hospital deaths, and patient dispositions recorded in the NIS discharge abstracts. The second group of outcomes measures was derived from the AHRQ patient safety indicators, which consist of twenty indicators designed to identify complications or adverse events during hospitalization with reasonable validity and specificity and the potential for fostering quality improvement^38,39. Details on the development and validation of these indicators and on the variables and ICD-9-CM codes used to define them, along with computer programs applying the patient safety indicators to hospital discharge data, are downloadable from the AHRQ website³⁸. Patient safety indicators include carefully designed inclusion and exclusion criteria to screen out adverse events that are not preventable. Because these criteria differ from one patient safety indicator to another, the pools of patients at risk for different patient safety indicator events differ. The following four patient safety indicators are of primary concern to patients who undergo hip procedures, and therefore were included in the present study:

Postoperative hematoma or hemorrhage requiring an operative intervention after a surgical procedure has been performed, except in patients with a principal diagnosis of hematoma or hemorrhage, patients in whom the only operating room procedure done was to control hemorrhage or to drain a hematoma, and patients in whom a procedure for postoperative control of hemorrhage or drainage of a hematoma was done before the first operating room procedure.Postoperative pulmonary embolism or deep vein thrombosis that was diagnosed after an operative procedure, except in patients with a principal diagnosis of pulmonary embolism or deep vein thrombosis, patients in whom the only operating room procedure done was for interruption of the vena cava, and patients in whom a procedure for interruption of the vena cava was done before or on the same day as the first operating room procedure.Postoperative infection—i.e., a diagnosis code for infection in the discharge summary of a patient who had a length of stay of four days or more and an elective operating room procedure, excluding those with the principal diagnosis of sepsis or infection and any diagnosis of an immunocompromised state or cancer.Decubitus ulcer or bed sores in a patient with a length of stay of four days or longer, except those with a principal diagnosis of decubitus ulcer or any diagnosis of skin disease, subcutaneous tissue disease, breast disease, pregnancy, childbirth, puerperium, hemiplegia, quadriplegia, spina bifida, or anoxic brain damage; those treated with débridement or a pedicle graft; and those transferred from an acute-care or long-term-care facility.

Postoperative pulmonary embolism or deep vein thrombosis that was diagnosed after an operative procedure, except in patients with a principal diagnosis of pulmonary embolism or deep vein thrombosis, patients in whom the only operating room procedure done was for interruption of the vena cava, and patients in whom a procedure for interruption of the vena cava was done before or on the same day as the first operating room procedure.

Postoperative infection—i.e., a diagnosis code for infection in the discharge summary of a patient who had a length of stay of four days or more and an elective operating room procedure, excluding those with the principal diagnosis of sepsis or infection and any diagnosis of an immunocompromised state or cancer.

Decubitus ulcer or bed sores in a patient with a length of stay of four days or longer, except those with a principal diagnosis of decubitus ulcer or any diagnosis of skin disease, subcutaneous tissue disease, breast disease, pregnancy, childbirth, puerperium, hemiplegia, quadriplegia, spina bifida, or anoxic brain damage; those treated with débridement or a pedicle graft; and those transferred from an acute-care or long-term-care facility.

The third group of patient outcomes measures consisted of readmission data derived from state inpatient databases of five states, as listed above. Readmission measures were created on the basis of encrypted patient identification, discharge date, and admission date. If readmission occurred within thirty days after a patient was discharged from a hospitalization during which a hip replacement procedure had been performed, it was counted as a thirty-day all-cause readmission¹². Ninety-day all-cause readmissions were similarly defined. When a readmission resulted in another hip procedure it was termed a thirty or ninety-day readmission with a hip procedure. We could not capture thirty-day readmissions that occurred in December or ninety-day readmissions that occurred after October, since only admission data from the calendar year 2003 were used. In addition, because patient identification was assigned by the hospital, readmission to a hospital other than the first admitting hospital was not captured.

Statistical Methods

National estimates of hip procedures according to patient and hospital characteristics were tabulated. National estimates and standard errors were calculated for patient outcomes measures, with the exception of readmission measures. Since the readmission calculations included all 2003 discharges from the five states, readmission measures were estimated without weights or standard errors. The characteristics and outcomes of patients with any type of surgery were compared with those in each of the three hip-replacement groups.

Multiple logistic regression analyses were conducted to assess the relationship between patient and hospital characteristics and patient outcomes measures. The regressions were run twice to assess the effects of comorbidities on outcomes variables: once with use of the individual comorbidity indicators and once with use of the comorbidity summary categories. P values of <0.05 and <0.01 were accepted as significant and highly significant, respectively.

Results

National Estimates of Hip Procedures and Patient Characteristics

Table I shows the national estimates of the numbers of the three types of hip replacement procedures in comparison with the total number of surgical procedures performed in 2003 in the United States. Total hip replacement represented 1% of all surgical procedures; partial hip replacement, 0.5%; and revision of hip replacement, 0.2%.

View Larger

TABLE I National Estimate of Numbers of Hip Replacements According to Type and Distribution According to Various Patient and Hospital Characteristics

	Hip Replacement
Characteristic	Total	Partial	Revision	All Surgical Patients
Total no. of procedures in sample	41,744	21,921	7,416	4,202,636
Weighted estimate (stand. error)	201,420 (7921)	105,408 (2697)	35,851 (1987)	20,105,637 (435,536)
Distribution by patient and hospital characteristics (%)
Age
18-24 yr	0.3	0.1	0.2	9
25-64 yr	40	8	36	54
65-74 yr	29	14	26	15
75-84 yr	25	41	29	15
=85 yr	5	37	8	6
Gender
Male	42	26	42	37
Female	58	74	58	63
Comorbid diseases*
Congestive heart failure	3	16	6	6
Chronic pulmonary disease	13	20	14	13
Diabetes	11	16	12	16
Rheumatoid arthritis	3	3	7	2
Fluid and electrolyte disorders	6	21	9	12
Obesity	7	1	5	4
No. of comorbidities
0	25	9	20	36
1	34	21	31	22
2	24	28	25	19
=3	17	42	24	23
Admission type
Emergency	12	79	22	54
Planned	78	11	67	34
Data missing	10	10	11	12
Primary payer
Medicare	58	87	66	39
Medicaid	3	2	4	15
Private	36	9	28	38
Other	3	2	2	8
Hospital ownership†
Government (n = 120)	9	11	10	3
Private, nonprofit (n = 485)	80	75	79	74
Private, investor owned (n = 119)	11	14	11	13
Hospital size†
Small (n = 170)	11	11	10	10
Medium (n = 240)	26	27	24	25
Large (n = 313)	63	62	66	65
Location/teaching status†
Rural (n = 235)	13	19	10	12
Urban non-teaching (n = 333)	41	47	35	41
Urban teaching (n = 155)	46	34	55	47
No. of elective total hip replacements/yr†
=10 (n = 315)	18	24	18	24
11-99 (n = 305)	35	45	28	41
=100 (n = 104)	47	31	54	34

Other comorbid diseases not represented in the table included valvular diseases, hypothyroidism, peripheral vascular diseases, paralysis, other neurological disorders, renal failure, liver disease, peptic ulcer disease, AIDS, lymphoma, metastatic cancer, solid tumor without metastasis, coagulopathy, deficiency anemias, depression, hypertension, weight loss, chronic blood loss anemia, alcohol abuse, and psychoses. †The number of hospitals in each category is given in parentheses.

Add to My JBJS

TABLE I National Estimate of Numbers of Hip Replacements According to Type and Distribution According to Various Patient and Hospital Characteristics

	Hip Replacement
Characteristic	Total	Partial	Revision	All Surgical Patients
Total no. of procedures in sample	41,744	21,921	7,416	4,202,636
Weighted estimate (stand. error)	201,420 (7921)	105,408 (2697)	35,851 (1987)	20,105,637 (435,536)
Distribution by patient and hospital characteristics (%)
Age
18-24 yr	0.3	0.1	0.2	9
25-64 yr	40	8	36	54
65-74 yr	29	14	26	15
75-84 yr	25	41	29	15
=85 yr	5	37	8	6
Gender
Male	42	26	42	37
Female	58	74	58	63
Comorbid diseases*
Congestive heart failure	3	16	6	6
Chronic pulmonary disease	13	20	14	13
Diabetes	11	16	12	16
Rheumatoid arthritis	3	3	7	2
Fluid and electrolyte disorders	6	21	9	12
Obesity	7	1	5	4
No. of comorbidities
0	25	9	20	36
1	34	21	31	22
2	24	28	25	19
=3	17	42	24	23
Admission type
Emergency	12	79	22	54
Planned	78	11	67	34
Data missing	10	10	11	12
Primary payer
Medicare	58	87	66	39
Medicaid	3	2	4	15
Private	36	9	28	38
Other	3	2	2	8
Hospital ownership†
Government (n = 120)	9	11	10	3
Private, nonprofit (n = 485)	80	75	79	74
Private, investor owned (n = 119)	11	14	11	13
Hospital size†
Small (n = 170)	11	11	10	10
Medium (n = 240)	26	27	24	25
Large (n = 313)	63	62	66	65
Location/teaching status†
Rural (n = 235)	13	19	10	12
Urban non-teaching (n = 333)	41	47	35	41
Urban teaching (n = 155)	46	34	55	47
No. of elective total hip replacements/yr†
=10 (n = 315)	18	24	18	24
11-99 (n = 305)	35	45	28	41
=100 (n = 104)	47	31	54	34

About 60% of the patients treated with total hip replacement and those treated with revision hip replacement were sixty-five years of age or older, and most of their admissions to the hospital were planned. About 80% of the patients treated with partial hip replacement were seventy-five years of age or older, and about 80% of their admissions were emergency admissions. At least 75% of the patients who underwent any hip procedure had one or more comorbid conditions, and >40% of the patients who underwent partial hip replacement had three or more comorbidities.

About 20% of all hip procedures were done in 315 hospitals that performed ten or fewer elective total hip replacements annually, and 90% of the admissions for a hip procedure at one of these low-volume hospitals were emergency admissions. About 50% of the total hip replacement procedures were done in 104 hospitals that performed 100 or more elective total hip replacements a year, and only 6% of the admissions for total hip replacement at one of these high-volume hospitals were emergency admissions.

Table II provides the primary reasons for each of the three hip procedures. More than 80% of the patients who underwent total hip replacement were admitted with a principal diagnosis of osteoarthritis. Nearly 90% of the patients who had partial hip replacement were admitted after a fracture of the neck of the femur. About 90% of the patients who underwent revision hip replacement had a complication related to the device, implant, or graft as the principal diagnosis.

View Larger

TABLE II Most Frequent Five Principal Diagnoses* in Patients Who Underwent Hip Replacement

Rank	Total Hip Replacement	%	Partial Hip Replacement	%	Revision hip replacement	%
1	Osteoarthritis	81	Fracture of neck of femur (hip)	88	Complication of device, implant, or graft	89
2	Other bone, musculoskeletal diseases	9	Pathological fracture	3	Osteoarthritis	2
3	Fracture of neck of femur (hip)	4	Other bone, musculoskeletal diseases	3	Fracture of neck of femur (hip)	2
4	Complication of device, implant, or graft	1	Complication of device, implant, or graft	2	Fracture of lower limb	2
5	Rheumatoid arthritis and related diseases	1	Osteoarthritis	1	Other acquired deformities	2

The listed principal diagnoses were grouped with use of the clinical classification system developed by AHRQ; the ICD-9-CM codes for each class are available at www.hcup-us.ahrq.gov/toolssoftware/ccs/ccs.jsp.

Add to My JBJS

TABLE II Most Frequent Five Principal Diagnoses* in Patients Who Underwent Hip Replacement

Rank	Total Hip Replacement	%	Partial Hip Replacement	%	Revision hip replacement	%
1	Osteoarthritis	81	Fracture of neck of femur (hip)	88	Complication of device, implant, or graft	89
2	Other bone, musculoskeletal diseases	9	Pathological fracture	3	Osteoarthritis	2
3	Fracture of neck of femur (hip)	4	Other bone, musculoskeletal diseases	3	Fracture of neck of femur (hip)	2
4	Complication of device, implant, or graft	1	Complication of device, implant, or graft	2	Fracture of lower limb	2
5	Rheumatoid arthritis and related diseases	1	Osteoarthritis	1	Other acquired deformities	2

Short-Term Patient Outcomes Following Hip Procedures

Table III presents the national estimates of short-term patient outcomes following total hip replacement, partial hip replacement, and revision hip replacement compared with those in patients who had undergone any surgical procedure in 2003. Patients who had undergone a hip procedure had an average length of stay in the hospital and total charges that were numerically comparable with those for patients who had undergone any surgical procedure. Patients who had undergone any of the three hip procedures were less likely than the other surgical patients to be transferred to another acute-care hospital but substantially more likely to be discharged to a nursing home or another type of facility.

View Larger

TABLE III Short-Term Patient Outcomes After Three Types of Hip Replacement and for Patients with Any Surgical Procedure

	Hip Replacement
Patient Outcome	Total	Partial	Revision	All Surgical Patients
National estimates (stand. error*)
Average hospital stay (days)	4.29† (0.05)	6.89† (0.06)	5.93† (0.13)	5.23 (0.05)
Average total charges ($)	34,951† (943)	35,985† (740)	46,849† (2726)	27,733 (833)
In-hospital mortality (%)	0.33† (0.03)	3.04 (0.11)	0.84† (0.11)	2.81 (0.04)
Transfer to short-term hospital (%)	0.57† (0.12)	0.93† (0.11)	0.85† (0.14)	1.70 (0.05)
Transfer to skilled nursing, intermediate-care, or another type of facility (%)	47.42† (1.23)	81.71† (0.62)	48.26† (0.14)	12.42 (0.23)
Decubitus ulcer (%)	0.28† (0.03)	1.88† (0.11)	1.27† (0.13)	0.90 (0.03)
Postop. hemorrhage or hematoma (%)	0.05† (0.01)	0.05 (0.02)	0.13† (0.04)	0.09 (0.002)
Postop. pulmonary embolism or deep vein thrombosis (%)	0.68† (0.05)	1.36† (0.09)	1.08† (0.18)	0.40 (0.02)
Postop. infection (%)	0.05 (0.01)	0.06 (0.02)	0.25† (0.06)	0.07 (0.003)
States readmission data‡	N = 44,520	N = 22,810	N = 6,815	N = 3,690,899
30-day all-cause readmission (%)	4.91	12.15	8.48	9.00
30-day readmission with hip procedure (%)	0.79	0.91	1.53	6.35§
90-day all-cause readmission (%)	8.94	21.14	15.72	15.09
90-day readmission with hip procedure (%)	2.15	1.61	3.99	11.39§

Standard errors were calculated on the basis of sampling weights in the 2003 National Inpatient Sample (NIS). †Significantly different from the estimate for all surgical patients at p < 0.01. ‡Standard errors for readmissions were not determined because the readmission calculations were based on all 2003 discharges from the five state inpatient databases. §Readmission with any surgical procedure.

Add to My JBJS

TABLE III Short-Term Patient Outcomes After Three Types of Hip Replacement and for Patients with Any Surgical Procedure

	Hip Replacement
Patient Outcome	Total	Partial	Revision	All Surgical Patients
National estimates (stand. error*)
Average hospital stay (days)	4.29† (0.05)	6.89† (0.06)	5.93† (0.13)	5.23 (0.05)
Average total charges ($)	34,951† (943)	35,985† (740)	46,849† (2726)	27,733 (833)
In-hospital mortality (%)	0.33† (0.03)	3.04 (0.11)	0.84† (0.11)	2.81 (0.04)
Transfer to short-term hospital (%)	0.57† (0.12)	0.93† (0.11)	0.85† (0.14)	1.70 (0.05)
Transfer to skilled nursing, intermediate-care, or another type of facility (%)	47.42† (1.23)	81.71† (0.62)	48.26† (0.14)	12.42 (0.23)
Decubitus ulcer (%)	0.28† (0.03)	1.88† (0.11)	1.27† (0.13)	0.90 (0.03)
Postop. hemorrhage or hematoma (%)	0.05† (0.01)	0.05 (0.02)	0.13† (0.04)	0.09 (0.002)
Postop. pulmonary embolism or deep vein thrombosis (%)	0.68† (0.05)	1.36† (0.09)	1.08† (0.18)	0.40 (0.02)
Postop. infection (%)	0.05 (0.01)	0.06 (0.02)	0.25† (0.06)	0.07 (0.003)
States readmission data‡	N = 44,520	N = 22,810	N = 6,815	N = 3,690,899
30-day all-cause readmission (%)	4.91	12.15	8.48	9.00
30-day readmission with hip procedure (%)	0.79	0.91	1.53	6.35§
90-day all-cause readmission (%)	8.94	21.14	15.72	15.09
90-day readmission with hip procedure (%)	2.15	1.61	3.99	11.39§

The in-hospital mortality risk was estimated to be 0.33% (95% confidence interval, 0.27% to 0.36%) for total hip replacement and 0.84% (95% confidence interval, 0.63% to 1.05%) for revision hip replacement. These risks were significantly lower than the risk of 3.04% (95% confidence interval, 2.83% to 3.20%) for partial hip replacement and the risk of 2.81% (95% confidence interval, 2.73% to 2.89%) for other types of surgery (p < 0.01). Patients who had undergone any of the three hip procedures had higher rates of perioperative thromboembolic events than did the other surgical patients (p < 0.01). Notably, the rate of decubitus ulcers in the patients who had undergone partial hip replacement was double that in the other surgical patients and more than six times higher than that in the patients treated with total hip replacement. The patients treated with revision hip replacement had a rate of postoperative infection that was four times higher than the rate in the other three groups.

All-cause readmission rates within thirty and ninety days were lower following total hip replacement and higher following partial hip replacement than they were following revision hip replacement and following other surgical procedures. The readmission rates were substantially lower if only the readmissions during which a hip procedure had been performed were counted. There were twice as many readmissions within ninety days as there were within thirty days.

Patient and Hospital Factors Associated with Patient Outcomes

Tables in the Appendix present the results of the logistic regression models for in-hospital mortality following hip procedures. Advanced age and some comorbid diseases (e.g., congestive heart failure and fluid and electrolyte disorders) were associated with increased in-hospital mortality following the three types of hip surgery. Patients for whom the admission had been planned had a lower mortality rate than those who had been admitted emergently. Hospital characteristics and volume were not significant predictors of in-hospital mortality. Similar to the findings regarding in-hospital mortality, the presence of comorbidities was consistently associated with higher odds of complications and readmissions, whereas private insurance was associated with lower odds. Advanced age was generally associated with worse outcomes, but it was significantly associated with a lower odds of readmission for a hip procedure. The effects of hospital characteristics and hospital volume were not significant or consistent.

Discussion

We estimate that about 200,000 total hip replacements, 100,000 partial hip replacements, and 36,000 revision hip replacements were performed in the United States in 2003. Most of the patients who underwent hip procedures were elderly and had multiple chronic conditions. Total hip replacements were usually performed in large hospitals after a planned admission of a patient with osteoarthritis. In contrast, partial hip replacements were generally performed in relatively smaller hospitals and in older, sicker patients, and they were usually done as emergency admissions after a hip fracture. As expected, revision hip replacements were usually performed to treat complications of earlier hip replacements.

Overall, the patient outcomes estimated in this study are consistent with previous findings^5-25. Compared with other surgical patients, patients treated with hip replacement—and especially those treated with partial hip replacement—had a significantly higher rate of postoperative thrombosis or pulmonary embolism. Patients treated with total hip replacement fared better than did other surgical patients with regard to all other outcomes measures studied. In contrast, patients treated with partial hip replacement had substantially higher rates of mortality and bed sores than did those treated with total hip replacement. One notable finding in association with revision hip replacement was the substantially higher rate of postoperative infection.

The readmission estimates derived from this study were also comparable with previous estimates of all-cause readmissions¹². One unique finding of this study was that readmission rates were four to thirteen times lower if only readmissions requiring another hip procedure were counted. Because hip replacements are usually performed in elderly patients with multiple chronic conditions, many readmissions after hip replacements are probably due to conditions unrelated to the hip replacement per se.

This study confirms that frailty and severity, as indicated by advanced age and comorbid conditions^26,27, are significant predictors of worse patient outcomes after hip replacement. It also suggests that higher socioeconomic status, as represented by the patient having private insurance, is associated with better outcomes. This study failed to show any significant relationship between hospital volume and patient outcomes, which is consistent with some previous findings^31,34 but contradictory to others^28,30,32,33. One plausible explanation is that the volume effect lies with surgeon volume^28-32. Since the administrative data could not identify the surgeons who performed the operations, surgeon-specific volume effects could not be determined.

The inherent limitations of using hospital claims data to measure patient outcomes should be noted³⁹. First, the validity of the ICD-9-CM codes for identifying hip replacement procedures has not been examined, to our knowledge. However, given the clinical value and cost of a hip replacement, it is unlikely that the procedure would not be coded in the discharge summary if it had been performed and also unlikely that the procedure would be coded if it had not been performed. Second, the data do not capture postdischarge mortality or many types of complications, such as dislocations; some of the complications might be missed, miscoded, or misclassified; and the calculation of readmissions was able to identify only readmissions to the same hospital in the same calendar year, leading to underestimated readmission rates. Third, because of the nature of our data, this study did not capture the risk of adverse events related to the experience of the surgeon, type of device, experience of the operating room staff, type of anesthesia, and other clinical variables. Also, the data do not capture clinically relevant risk factors such as baseline activity level, function, or pain. Lastly, it should be noted that, because of the large volume of the administrative data, some significant effects or differences may be very small in magnitude and not clinically relevant. It should also be noted that the NIS is not a random sample of hospital discharges, but a sample assembled on the basis of hospital discharges from thirty-seven states to approximate a 20% sample of hospital discharges in the United States³⁵. As a result, our estimates may not be nationally representative.

In conclusion, this study provides comprehensive assessments of the three types of hip replacement performed in the United States in 2003. Overall, total hip replacement and revision hip replacement appear to be safe; the risk of adverse patient outcomes, especially following partial hip replacement, is mostly attributable to advanced age, comorbid diseases, and nonelective admissions.

Appendix

Tables showing adjusted odds ratios for risk factors and the results of the regression analysis are available with the electronic versions of this article, on our web site at (go to the article citation and click on "Supplementary Material") and on our quarterly CD-ROM (call our subscription department, at 781-449-9780, to order the CD-ROM). ?

Acknowledgements

Note: The authors thank Barbara Buch, MD, the Food and Drug Administration Center for Device and Radiological Health, for input in the development of the paper; Zhengyi Fang, PhD, Social and Scientific Systems, for excellent computing support; and Willaim Baine, MD, Scott Smith, PhD, and Art Sedrakyan, MD, PhD, the Agency for Healthcare Research and Quality, for useful comments. The authors also acknowledge the statewide data organizations that participate in the HCUP Nationwide Inpatient Sample (NIS) 2003.

References

Ethgen O, Bruyere O, Richy F, Dardennes C, Reginster JY. Health-related quality of life in total hip and total knee arthroplasty. A qualitative and systematic review of the literature. J Bone Joint Surg Am.2004;86: 963-74.86963 2004 [PubMed]

Seagroatt V, Tan HS, Goldacre M, Bulstrode C, Nugent I, Gill L. Elective total hip replacement: incidence, emergency readmission rate, and postoperative mortality. BMJ.1991;303: 1431-5.3031431 1991 [PubMed][CrossRef]

Abbott KC, Bucci JR, Agodoa LY. Total hip arthroplasty in chronic dialysis patients in the United States. J Nephrol.2003;16: 34-9.1634 2003

Peterson MG, Hollenberg JP, Szatrowski TP, Johanson NA, Mancuso CA, Charlson ME. Geographic variations in the rates of elective total hip and knee arthroplasties among Medicare beneficiaries in the United States. J Bone Joint Surg Am.1992;74: 1530-9.741530 1992 [PubMed]

Dearborn JT, Harris WH. Postoperative mortality after total hip arthroplasty. An analysis of deaths after two thousand seven hundred and thirty-six procedures. J Bone Joint Surg Am.1998;80: 1291-4.801291 1998

Miller KA, Callaghan JJ, Goetz DD, Johnston RC. Early postoperative mortality following total hip arthroplasty in a community setting: a single surgeon experience. Iowa Orthop J.2003;23: 36-42.2336 2003

Whittle J, Steinberg EP, Anderson GF, Herbert R, Hochberg MC. Mortality after elective total hip arthroplasty in elderly Americans. Age, gender, and indication for surgery predict survival. Clin Orthop Relat Res.1993;295: 119-26.295119 1993 [PubMed]

Birtwistle SJ, Wilson K, Porter ML. Long-term survival analysis of total hip replacement. Ann R Coll Surg Engl.1996;78: 180-3.78180 1996

Nunley RM, Lachiewicz PF. Mortality after total hip and knee arthroplasty in a medium-volume university practice. J Arthroplasty.2003;18: 278-85.18278 2003 [PubMed][CrossRef]

Williams O, Fitzpatrick R, Hajat S, Reeves BC, Stimpson A, Morris RW, Murray DW, Rigge M, Gregg PJ; National Total Hip Replacement Outcome Study Steering Committee. Mortality, morbidity, and 1-year outcomes of primary elective total hip arthroplasty. J Arthroplasty.2002;17: 165-71.17165 2002 [CrossRef]

Parvizi J, Ereth MH, Lewallen DG. Thirty-day mortality following hip arthroplasty for acute fracture. J Bone Joint Surg Am.2004;86: 1983-8.861983 2004

Mahomed NN, Barrett JA, Katz JN, Phillips CB, Losina E, Lew RA,Guadagnoli E, Harris WH, Poss R, Baron JA. Rates and outcomes of primary and revision total hip replacement in the United States Medicare population. J Bone Joint Surg Am.2003;85: 27-32.8527 2003 [PubMed]

Brenkel IJ, Cook RE. Thromboprophylaxis in patients undergoing total hip replacement. Hosp Med.2003;64: 281-7.64281 2003 [PubMed]

Colwell CW Jr. Managing thromboembolic risk in hip and knee arthroplasty: state of the art. Orthopedics.2003;26(2 Suppl): s231-6.26s231 2003 [PubMed]

Wheeler HB, Anderson FA Jr. Prophylaxis against venous thromboembolism in surgical patients. Am J Surg.1991;161: 507-11.161507 1991 [PubMed][CrossRef]

White RH, Gettner S, Newman JM, Trauner KB, Romano PS. Predictors of rehospitalization for symptomatic venous thromboembolism after total hip arthroplasty. N Engl J Med.2000;343: 1758-64.3431758 2000 [PubMed][CrossRef]

Skinner HB, Schulz MM. Clinical implications of thromboprophylaxis in the management of total hip and knee arthroplasty. Am J Orthop.2002;31(9 Suppl): 20-30.3120 2002 [PubMed]

Swayze OS, Nasser S, Roberson JR. Deep venous thrombosis in total hip arthroplasty. Orthop Clin North Am.1992;23: 359-64.23359 1992

Lawrence VA, Hilsenbeck SG, Noveck H, Poses RM, Carson JL. Medical complications and outcomes after hip fracture repair. Arch Intern Med.2002;162: 2053-7.1622053 2002 [PubMed][CrossRef]

Howie C, Hughes H, Watts AC. Venous thromboembolism associated with hip and knee replacement over a ten-year period: a population-based study. J Bone Joint Surg Br.2005;87: 1675-80.871675 2005 [PubMed][CrossRef]

Kinkel S, Kaefer W, Reissig W, Puhl W, Kessler S. Revision total hip arthroplasty: the influence of gender and age on the perioperative complication rate. Acta Chir Orthop Traumatol Cech.2003;70: 269-73. Erratum in: Acta Chir Orthop Traumatol Cech. 2004;71:256.70269 2003

Moggio M, Goldner JL, McCollum DE, Beissinger SF. Wound infections in patients undergoing total hip arthroplasty. Ultraviolet light for the control of airborne bacteria. Arch Surg.1979;114: 815-23.114815 1979

Schmalzried TP, Amstutz HC, Au MK, Dorey FJ. Etiology of deep sepsis in total hip arthroplasty. The significance of hematogenous and recurrent infections. Clin Orthop Relat Res.1992;280: 200-7.280200 1992 [PubMed]

Wroblewski BM, del Sel HJ. Urethral instrumentation and deep sepsis in total hip replacement. Clin Orthop Relat Res.1980;146: 209-12.146209 1980

Boettcher WG. Total hip arthroplasties in the elderly. Morbidity, mortality, and cost effectiveness. Clin Orthop Relat Res.1992;274: 30-4.27430 1992

Greenfield S, Apolone G, McNeil BJ, Cleary PD. The importance of co-existent disease in the occurrence of postoperative complications and one-year recovery in patients undergoing total hip replacement. Comorbidity and outcomes after hip replacement. Med Care.1993;31: 141-54.31141 1993 [CrossRef]

Jain NB, Guller U, Pietrobon R, Bond TK, Higgins LD. Comorbidities increase complication rates in patients having arthroplasty. Clin Orthop Relat Res.2005;435: 232-8.435232 2005 [PubMed][CrossRef]

Katz JN, Losina E, Barrett J, Phillips CB, Mahomed NN, Lew RA, Guadagnoli E, Harris WH, Poss R, Baron JA. Association between hospital and surgeon procedure volume and outcomes of total hip replacement in the United States Medicare population. J Bone Joint Surg Am.2001;83: 1622-9.831622 2001

Riley G, Lubitz J. Outcomes of surgery among the Medicare aged: surgical volume and mortality. Health Care Financ Rev.1985;7: 37-47.737 1985

Sharkey PF, Shastri S, Teloken MA, Parvizi J, Hozack WJ, Rothman RH. Relationship between surgical volume and early outcomes of total hip arthroplasty: do results continue to get better? J Arthroplasty.2004;19: 694-9.19694 2004 [PubMed][CrossRef]

Solomon DH, Losina E, Baron JA, Fossel AH, Guadagnoli E, Lingard EA, Miner A, Phillips CB, Katz JN. Contribution of hospital characteristics to the volume-outcome relationship: dislocation and infection following total hip replacement surgery. Arthritis Rheum.2002;46: 2436-44.462436 2002 [CrossRef]

Taylor HD, Dennis DA, Crane HS. Relationship between mortality rates and hospital patient volume for Medicare patients undergoing major orthopaedic surgery of the hip, knee, spine, and femur. J Arthroplasty.1997;12: 235-42.12235 1997 [PubMed][CrossRef]

Kreder HJ, Deyo RA, Koepsell T, Swiontkowski MF, Kreuter W. Relationship between the volume of total hip replacements performed by providers and the rates of postoperative complications in the state of Washington. J Bone Joint Surg Am.1997;79: 485-94.79485 1997 [PubMed]

Kreder HJ, Williams JI, Jaglal S, Hu R, Axcell T, Stephen D. Are complication rates for elective primary total hip arthroplasty in Ontario related to surgeon and hospital volumes? A preliminary investigation. Can J Surg.1998;41: 431-7.41431 1998 [PubMed]

Agency for Healthcare Research and Quality. Healthcare Cost and Utilization Project (HCUP). . Accessed 2006 Nov 8.
http://www.ahrq.gov/data/hcup/

Jiang HJ, Andrews R, Stryer D, Friedman B. Racial/ethnic disparities in potentially preventable readmissions: the case of diabetes. Am J Public Health.2005;95: 1561-7.951561 2005 [PubMed][CrossRef]

Elixhauser A, Steiner C, Harris DR, Coffey RM. Comorbidity measures for use with administrative data. Med Care.1998;36: 8-27.368 1998 [CrossRef]

Agency for Healthcare Research and Quality. Patient Safety Indicators Download. . Accessed 2006 Nov 8.
http://www.qualityindicators.ahrq.gov/psi_download.htm

Zhan C, Miller M. Administrative data based patient safety research: a critical review. Qual Saf Health Care.2003;12Suppl 2: ii58-63.12ii58 2003

Topics

hip region ; hip joint ; hip replacement arthroplasty

Username

Password

Access for Patients

Forgot Password?

Have a subscription to the print edition?

Not a Subscriber?

Buy this Article

Get online access for 30 days for $35

New to JBJS?

Subscribe to the online edition for 30 days for $75

Register for a FREE limited account to get full access to all CME activities, to comment on public articles, or to sign up for alerts.

Have a subscription to the print edition?

Current subscribers to The Journal of Bone & Joint Surgery in either the print or quarterly DVD formats receive free online access to JBJS.org.

Activate your online account now

Forgot your password?

Enter your username and email address. We'll send you a reminder to the email address on record.

Username:*

Email Address:*

Forgot your username or need assistance? Please contact customer service at subs@jbjs.org. If your access is provided
by your institution, please contact you librarian or administrator for username and password information. Institutional
administrators, to reset your institution's master username or password, please contact subs@jbjs.org

References

Accreditation Statement

These activities have been planned and implemented in accordance with the Essential Areas and policies of the Accreditation Council for Continuing Medical Education (ACCME) through the joint sponsorship of the American Academy of Orthopaedic Surgeons and The Journal of Bone and Joint Surgery, Inc. The American Academy of Orthopaedic Surgeons is accredited by the ACCME to provide continuing medical education for physicians.

CME Activities Associated with This Article

Submit a Comment

Please read the other comments before you post yours. Contributors must reveal any conflict of interest.
Comments are moderated and will appear on the site at the discretion of JBJS editorial staff.

* = Required Field

Comment Author(s) * (if multiple authors, separate names by comma)

Example: John Doe

Affiliation & Institution*

Comment Title*

Comment*

Cancel

Print
PDF
Email

Recipient(s) will receive an email with a link (good for 5 days) to 'Incidence and Short-Term Outcomes of Primary and Revision Hip Replacement in the United States'.
Your Name:*
Example: John Doe

Email Address:* CC Me:
Enter your valid email address. Example: jdoe@example.com

Recipient's Email Address:*

Separate multiple email address with semi-colons (up to 5).

Subject:* 's The Journal of Bone & Joint Surgery: 'Incidence and Short-Term Outcomes of Primary and Revision Hip Replacement in the United States'
Subject for your email.

Message:

(Optional, message will truncate at 1000 characters)

Processing your request... Please Wait...

Copyright © in the material you requested is held by The Journal of Bone & Joint Surgery, Inc. (unless otherwise noted). This email ability is provided as a courtesy, and by using it you agree that that you are requesting the material solely for personal, non-commercial use, and that it is subject to Journal of Bone & Joint Surgery, Inc.'s Terms of Use. The information provided in order to email this topic will not be used to send unsolicited email, nor will it be furnished to third parties. Please refer to The Journal of Bone & Joint Surgery Inc.'s Privacy Policy for further information.

Copyright © The Journal of Bone & Joint Surgery Inc. All rights reserved.
Share
Get Citation

Chunliu Zhan, Ronald Kaczmarek, Nilsa Loyo-Berrios, Judith Sangl, Roselie A. Bright; Incidence and Short-Term Outcomes of Primary and Revision Hip Replacement in the United States. The Journal of Bone & Joint Surgery. 2007 Mar;89(3):526-533.

Download citation file:

RIS (Zotero)

EndNote

BibTex

Medlars

ProCite

RefWorks

Reference Manager

Copyright © The Journal of Bone and Joint Surgery, Inc.
Rights & Permissions
Article Alerts

Processing your request... Please Wait.
Submit a Comment
Data Supplements