Journal Logo

Scientific Articles

In-Bundle Surgeons More Likely Select Cemented Femoral Fixation in Total Hip Arthroplasty for At-Risk Patients

The Medicare Comprehensive Care for Joint Replacement Bundled Model

Edelstein, Adam I. MD1; Hume, Eric L. MD2; Pezzin, Liliana E. PhD, JD1; McGinley, Emily L. MS, MPH1; Dillingham, Timothy R. MD, MS2,a

Author Information
doi: 10.2106/JBJS.OA.20.00126
  • Open
  • Disclosures

Abstract

Total hip arthroplasty (THA) and total knee arthroplasty (TKA) are the most common inpatient procedures among Medicare beneficiaries, and projections indicate that utilization of these procedures will continue to rise1,2. In an effort to control costs and improve quality of care, the U.S. Centers for Medicaid & Medicare Services (CMS) introduced alternative payment models (APMs) for arthroplasty care3. The Comprehensive Care for Joint Replacement (CJR) initiative was introduced in 2016 as a mandatory, broad-based bundled APM in which payments are disbursed for an entire episode of care including acute and post-acute services for 90 days after discharge1.

Institutions performing THA and TKA in bundled APMs have sought to control costs by lowering internal expenditures, reducing inpatient length of stay, minimizing readmissions and complications by optimizing modifiable risk factors prior to the surgical procedure, and discharging patients to home instead of post-acute facilities4,5. Individual institutions that have voluntarily participated in bundled APMs have been effective in lowering costs and improving quality metrics with lower readmission and complication rates6-8. However, population-based analyses of bundled APMs for THA and TKA across multiple centers have found no improvements in quality metrics and have shown that almost all cost savings were related to changes in discharge disposition9,10. In light of these conflicting findings, further investigation into how bundled APMs affect the quality of arthroplasty care is warranted. Specifically, it is unknown how bundled APMs may influence surgeons’ decisions that directly impact patient care and outcomes.

Therefore, we sought to investigate how participation in a bundled APM affects surgeon decision-making. Surgeon selection of a cemented or cementless femoral component in THA alters the complication profile among patients with poor bone quality, with risks related to cementless stems including periprosthetic fracture, stem subsidence, and failure of osseointegration11-14. The occurrence of these complications may require costly readmission and reoperation. Specifically, the purpose of this study was to compare the utilization of femoral component fixation modes for surgeons practicing in areas subject to the mandatory bundled payment model compared with those practicing in areas exempt from the CJR policy. We hypothesized that surgeons subject to the CJR bundled payment model would be more risk-averse and therefore more likely to select cemented femoral fixation for at-risk patients, namely elderly women.

Materials and Methods

Cohort and Data Sources

This was a retrospective review of Medicare data. Medicare claims data from the CMS were used to identify all elective, primary THAs among Fee-for-Service (FFS) beneficiaries in 2017 and 2018. All primary THA admissions were identified by selecting admissions with a diagnosis-related group (DRG) of 469 or 470 with an International Classification of Diseases, Tenth Revision (ICD-10) procedure code for primary THA (listed below). Arthroplasties for fracture, neoplasm, infection, or revision were excluded according to CMS methodology for quality reporting15. Patients were excluded if they were not enrolled in FFS Medicare for at least 12 months prior to the THA admission in order to calculate comorbidity.

Outcome

The use of cement fixation was the main outcome and was identified using the following ICD-10 procedure codes present on the index THA admission: cemented fixation: 0SR9019, 0SR9029, 0SR9039, 0SR9049, 0SR9069, 0SR90J9, 0SRB019, 0SRB029, 0SRB039, 0SRB049, 0SRB069, and 0SRB0J9; and uncemented fixation: 0SR901A, 0SR902A, 0SR903A, 0SR904A, 0SR906A, 0SR90JA, 0SRB01A, 0SRB02A, 0SRB03A, 0SRB04A, 0SRB06A, and 0SRB0JA.

Other Variables

Patient age (dichotomized as 66 to 74 years and ≥75 years), sex, and race or ethnicity (African American or Black, Hispanic, White non-Hispanic, other) were identified from the Medicare enrollment file. The age threshold of ≥75 years was selected because this is the age above which registry data have shown clear advantages to cemented femoral fixation, presumably because of poorer bone stock with advanced age, and prior studies used this age to stratify analyses14,16. Medicare claims files were used to calculate comorbidity for the 12 months prior to the THA admission using the Elixhauser index17,18. Dual enrollment, as a proxy for low-income status, was identified from the Medicare enrollment file and was considered positive if the beneficiary was enrolled in Medicaid and/or a state buy-in program during the month of the THA admission. To identify facilities within mandatory bundling areas, the Metropolitan Statistical Area (MSA) of the facility was identified using CMS Provider of Services files.

Analysis

Sociodemographic and admission characteristics of THA admissions, stratified by sex, were compared according to cement fixation status. The stratification of the cohort by sex was performed given the known differences in bone quality between men and women, as has been performed in prior studies14,19,20. Multivariable logit regression models were then used to assess the impact of practice in a bundled payment area and the likelihood of cement usage, controlling for patient age, race or ethnicity, number of comorbidities, dual-enrollment status, and Census division of the hospital. All analyses were performed using Stata 16 (StataCorp) within the CMS Virtual Research Data Center (VRDC). Institutional review board approval was obtained prior to data analysis.

Results

There were 118,676 THAs with ICD-10-Procedure Coding System (PCS) codes that specified the use of a cemented or a cementless femoral component. Of those, 10,772 patients (9.1%) received cemented femoral components.

Table I shows the summary characteristics of cemented and uncemented surgical procedures among female patients. About 1 in 10 female patients (8,014 surgical procedures [10.9%]) received cemented femoral components, and the remaining 65,510 surgical procedures (89.1%) received uncemented femoral components. Women who received cemented components, compared with women who received uncemented components, were significantly older at a mean age (and standard deviation) of 78.3 ± 6.9 years compared with 74.5 ± 6.1 years (p < 0.001); were more likely to be White at 94.0% compared with 92.7% (p < 0.001); were more likely to be poor, as measured by dual enrollment in Medicare and Medicaid, at 5.0% compared with 4.1% (p < 0.001); and had a higher comorbidity burden, with a mean Elixhauser index of 2.6 ± 2.2 compared with 2.3 ± 2.0 (p < 0.001). There was also substantial geographic variation in the use of cemented or cementless components (p < 0.001). The mean length of the surgical acute care stay was also longer in the cemented fixation group (2.5 ± 1.4 days) than in the uncemented fixation group (2.1 ± 1.2 days) (p < 0.001). Finally, a higher percentage of persons who received cement resided in an MSA subjected to the mandatory CJR bundling policy (35.6% compared with 32.9%; p < 0.001).

TABLE I - Summary Statistics, Overall and by Cement Status: Female Patients
Variables Total Cemented Uncemented P Value
No. of patients* 73,524 (100.0%) 8,014 (10.9%) 65,510 (89.1%)
Age <0.001
 Mean(yr) 74.9 ± 6.3 78.3 ± 6.9 74.5 ± 6.1
 66 to 74 years* 38,708 (52.6%) 2,620 (32.7%) 36,088 (55.1%)
 ≥75 years* 34,816 (47.4%) 5,394 (67.3%) 29,422 (44.9%)
Race or ethnicity* <0.001
 White, non-Hispanic 68,247 (92.8%) 7,531 (94.0%) 60,716 (92.7%)
 African American or Black 2,802 (3.8%) 236 (2.9%) 2,566 (3.9%)
 Hispanic 1,400 (1.9%) 148 (1.8%) 1,252 (1.9%)
 Other 1,075 (1.5%) 99 (1.2%) 976 (1.5%)
Dual enrollment* <0.001
 No 70,447 (95.8%) 7,612 (95.0%) 62,835 (95.9%)
 Yes 3,077 (4.2%) 402 (5.0%) 2,675 (4.1%)
Comorbidities <0.001
 Mean 2.3 ± 2.1 2.6 ± 2.2 2.3 ± 2.0
 0* 12,469 (17.0%) 1,161 (14.5%) 11,308 (17.3%)
 1* 17,778 (24.2%) 1,734 (21.6%) 16,044 (24.5%)
 2* 15,880 (21.6%) 1,670 (20.8%) 14,210 (21.7%)
 3* 10,971 (14.9%) 1,271 (15.9%) 9,700 (14.8%)
 ≥4* 16,426 (22.3%) 2,178 (27.2%) 14,248 (21.7%)
Census division* <0.001
 Northeast 4,594 (6.2%) 524 (6.5%) 4,070 (6.2%)
 Mid-Atlantic 10,329 (14.0%) 1,273 (15.9%) 9,056 (13.8%)
 South Atlantic 14,032 (19.1%) 1,210 (15.1%) 12,822 (19.6%)
 East North Central 13,692 (18.6%) 1,412 (17.6%) 12,280 (18.7%)
 East South Central 3,581 (4.9%) 481 (6.0%) 3,100 (4.7%)
 West North Central 6,185 (8.4%) 811 (10.1%) 5,374 (8.2%)
 West South Central 6,048 (8.2%) 593 (7.4%) 5,455 (8.3%)
 Mountain 6,192 (8.4%) 750 (9.4%) 5,442 (8.3%)
 Pacific 8,871 (12.1%) 960 (12.0%) 7,911 (12.1%)
Length of stay(days) 2.1 ± 1.2 2.5 ± 1.4 2.1 ± 1.2 <0.001
Bundling area* <0.001
 Yes 24,431 (33.2%) 2,852 (35.6%) 21,579 (32.9%)
 No 49,093 (66.8%) 5,162 (64.4%) 43,931 (67.1%)
*The values are given as the number of patients, with the percentage in parentheses.
The values are given as the mean and the standard deviation.

Table II shows the summary statistics among male patients undergoing THA. Among those, 2,758 patients (6.1%) received cemented femoral components, and 42,394 (93.9%) received uncemented femoral components. As with the female patients, the male patients who received cemented fixation, compared with those who received uncemented fixation, were significantly older at a mean age of 77.3 ± 6.8 years compared with 74.2 ± 5.9 years (p < 0.001); were more likely to be White at 95.1% compared with 93.8% (p = 0.046); and had a higher comorbidity burden, with a mean Elixhauser index of 2.8 ± 2.4 compared with 2.4 ± 2.1 (p < 0.001). Here again, there was marked geographic variation (p < 0.001). The cemented fixation group had a longer mean length of stay at 2.3 ± 1.6 days compared with the uncemented fixation group at 1.9 ± 1.3 days (p < 0.001). However, in contrast to findings for female patients, there was no significant difference (p = 0.36) in the percentage of patients residing in a mandatory CJR bundling MSA at 32.0% compared with those residing in a non-bundling MSA at 32.9%.

TABLE II - Summary Statistics, Overall and by Cement Status: Male Patients
Total Cemented Uncemented P Value
No. of patients* 45,152 (100.0%) 2,758 (6.1%) 42,394 (93.9%)
Age <0.001
 Mean(yr) 74.4 ± 6.0 77.3 ± 6.8 74.2 ± 5.9
 66 to 74 years* 25,219 (55.9%) 1,037 (37.6%) 24,182 (57.0%)
 ≥75 years* 19,933 (44.1%) 1,721 (62.4%) 18,212 (43.0%)
Race or ethnicity* 0.046
 White, non-Hispanic 42,401 (93.9%) 2,622 (95.1%) 39,779 (93.8%)
 African American or Black 1,451 (3.2%) 66 (2.4%) 1,385 (3.3%)
 Hispanic 726 (1.6%) 37 (1.3%) 689 (1.6%)
 Other 574 (1.3%) 33 (1.2%) 541 (1.3%)
Dual enrollment* 0.21
 No 44,190 (97.9%) 2,690 (97.5%) 41,500 (97.9%)
 Yes 962 (2.1%) 68 (2.5%) 894 (2.1%)
Comorbidities <0.001
 Mean 2.4 ± 2.2 2.8 ± 2.4 2.4 ± 2.1
 0* 7,610 (16.9%) 372 (13.5%) 7,238 (17.1%)
 1* 10,559 (23.4%) 550 (19.9%) 10,009 (23.6%)
 2* 9,295 (20.6%) 550 (19.9%) 8,745 (20.6%)
 3* 6,637 (14.7%) 434 (15.7%) 6,203 (14.6%)
 ≥4* 11,051 (24.5%) 852 (30.9%) 10,199 (24.1%)
Census division* <0.001
 Northeast 2,669 (5.9%) 112 (4.1%) 2,557 (6.0%)
 Mid-Atlantic 5,918 (13.1%) 378 (13.7%) 5,540 (13.1%)
 South Atlantic 8,933 (19.8%) 450 (16.3%) 8,483 (20.0%)
 East North Central 8,312 (18.4%) 375 (13.6%) 7,937 (18.7%)
 East South Central 2,174 (4.8%) 191 (6.9%) 1,983 (4.7%)
 West North Central 3,822 (8.5%) 289 (10.5%) 3,533 (8.3%)
 West South Central 3,739 (8.3%) 265 (9.6%) 3,474 (8.2%)
 Mountain 3,919 (8.7%) 296 (10.7%) 3,623 (8.5%)
 Pacific 5,666 (12.5%) 402 (14.6%) 5,264 (12.4%)
Length of stay(days) 1.9 ± 1.3 2.3 ± 1.6 1.9 ± 1.3 <0.001
Bundling area* 0.36
 Yes 14,813 (32.8%) 883 (32.0%) 13,930 (32.9%)
 No 30,339 (67.2%) 1,875 (68.0%) 28,464 (67.1%)
*The values are given as the number of patients, with the percentage in parentheses.
The values are given as the mean and the standard deviation.

Coefficient estimates from multivariable analyses for the female group, shown in Table III, indicate that female patients in the CJR bundled payment model were significantly more likely to receive a cemented femoral component compared with female patients not in the CJR bundled model (odds ratio [OR], 1.11 [95% confidence interval (CI), 1.05 to 1.16]; p < 0.001), even after controlling for age, race, comorbidities, and other potential confounders. Cemented femoral components were also more likely in women ≥75 years of age (OR, 2.47 [95% CI, 2.35 to 2.60]; p < 0.001); those with a higher comorbidity burden, as determined with the Elixhauser index, of 3 (OR, 1.09 [95% CI, 1.00 to 1.19]; p = 0.045) and ≥4 (OR, 1.22 [95% CI, 1.13 to 1.32]; p < 0.001); and those who had dual enrollment (OR, 1.22 [95% CI, 1.09 to 1.36]; p < 0.001). African American or Black female patients were less likely than their White counterparts to receive cemented femoral components (OR, 0.78 [95% CI, 0.68 to 0.89]; p < 0.001).

TABLE III - Factors Associated with Likelihood of Receiving a Cemented Femoral Component
Female Patients Male Patients
OR* P Value OR* P Value
Bundling area
 No Reference Reference
 Yes 1.11 (1.05 to 1.16) <0.001 0.91 (0.83 to 0.99) 0.029
Age
 <75 years Reference Reference
 ≥75 years 2.47 (2.35 to 2.60) <0.001 2.12 (1.96 to 2.30) <0.001
No. of comorbidities
 0 Reference Reference
 1 0.97 (0.90 to 1.05) 0.500 1.03 (0.90 to 1.18) 0.678
 2 1.01 (0.93 to 1.09) 0.817 1.13 (0.99 to 1.30) 0.079
 3 1.09 (1.00 to 1.19) 0.045 1.22 (1.05 to 1.40) 0.008
 ≥4 1.22 (1.13 to 1.32) <0.001 1.38 (1.22 to 1.57) <0.001
Race or ethnicity
 White Reference Reference
 African American or Black 0.78 (0.68 to 0.89) <0.001 0.77 (0.60 to 1.00) 0.046
 Hispanic 0.93 (0.78 to 1.11) 0.441 0.76 (0.54 to 1.07) 0.118
 Other 0.81 (0.66 to 1.00) 0.055 0.82 (0.57 to 1.17) 0.270
Dual enrollment
 No Reference Reference
 Yes 1.22 (1.09 to 1.36) 0.001 1.24 (0.96 to 1.61) 0.096
Census division
 Mid-Atlantic Reference Reference
 Northeast 0.95 (0.85 to 1.07) 0.417 0.61 (0.49 to 0.76) <0.001
 South Atlantic 0.70 (0.65 to 0.76) <0.001 0.76 (0.66 to 0.88) <0.001
 East North Central 0.86 (0.79 to 0.93) <0.001 0.69 (0.59 to 0.80) <0.001
 East South Central 1.19 (1.06 to 1.33) 0.003 1.43 (1.19 to 1.71) <0.001
 West North Central 1.12 (1.02 to 1.23) 0.023 1.21 (1.03 to 1.42) 0.021
 West South Central 0.83 (0.75 to 0.92) <0.001 1.12 (0.95 to 1.32) 0.194
 Mountain 1.08 (0.98 to 1.19) 0.127 1.21 (1.03 to 1.42) 0.022
 Pacific 0.90 (0.82 to 0.99) 0.027 1.15 (0.99 to 1.33) 0.07
*The values are given as the OR, with the 95% CI in parentheses.

There was substantial geographic variation in the use of cement, even after controlling for patients’ sociodemographic and health characteristics. Compared with women who underwent THA in the Mid-Atlantic, those in the East South Central region (OR, 1.19 [95% CI, 1.06 to 1.33]; p = 0.003) or the West North Central region (OR, 1.12 [95% CI, 1.02 to 1.23]; p = 0.023) were more likely to have cement fixation, and those in the South Atlantic region (OR, 0.70 [95% CI, 0.65 to 0.76]; p < 0.001), the East North Central region (OR, 0.86 [95% CI, 0.79 to 0.93]; p < 0.001), the West South Central region (OR, 0.83 [95% CI, 0.75 to 0.92]; p < 0.001), and the Pacific region (OR, 0.90 [95% CI, 0.82 to 0.99]; p = 0.027) were less likely to undergo a THA with cemented fixation.

In contrast, estimates from the multivariable regression for the male group indicate that male patients in the CJR bundled payment model were significantly less likely to receive a cemented femoral component compared with male patients not in the CJR bundled model (OR, 0.91 [95% CI, 0.83 to 0.99]; p = 0.029). As with female patients, cemented femoral components were more likely in male patients ≥75 years of age (OR, 2.12 [95% CI, 1.96 to 2.30]; p < 0.001) and those with a higher comorbidity burden, as determined by the Elixhauser index, of 3 (OR, 1.22 [95% CI, 1.05 to 1.40]; p = 0.008) or ≥4 (OR, 1.38 [95% CI, 1.22 to 1.57]; p < 0.001); cemented femoral components were less likely among African American or Black male patients (OR, 0.77 [95% CI, 0.60 to 1.00]; p = 0.046). Patterns of geographic variation in the use of cement among male patients generally mirrored those observed among female patients.

Discussion

The CMS has committed to transitioning Medicare payments to APMs15,21. Bundled APMs incentivize care coordination and efficiency by providing one collective payment to hospital, surgeon, and post-acute care providers. Bundle participation has been reported to spur standardization and optimization of perioperative care pathways that lower costs. Nevertheless, the impact of the bundle on surgical decision-making and, ultimately, on the quality of arthroplasty care has not been clearly defined. A fuller understanding of if and how bundled APMs impact surgeon decision-making is needed to gauge the effectiveness of APMs and to inform future policy-making. The risk of periprosthetic fracture and implant-related complications following THA may be less if the surgeon selects cemented femoral fixation for at-risk patients, and avoidance of those complications would have an impact on the bundle cost. In this study of >115,000 THA episodes, we found that surgeons performing THA in the mandatory CJR bundled payment model were significantly more likely to select cemented femoral fixation for female Medicare patients compared with surgeons not in the CJR bundled payment model.

Our findings are consistent with prior studies examining factors associated with poor bone health. These include advanced age, female sex, medical frailty, White race, and low socioeconomic status19,22-25. To our knowledge, this study is the first to report data on THA femoral fixation mode in a nationally representative population of older adults in the United States. This report was enabled by the mandatory adoption of ICD-10 PCS codes in 2015. The ICD-10 PCS system includes codes that specify the use of cemented implants compared with uncemented implants, whereas previous iterations of the ICD system did not.

The selection of the stem fixation mode varies widely by geography; cemented stems are utilized in >60% of cases in Sweden compared with <6% of cases among all individuals in the United States26,27. In the current study, the region with the highest cement rate (East South Central) had >60% higher utilization of cement than the region with the lowest cement rate (South Atlantic). These geographic differences reveal that non-patient factors such as surgeon training and familiarity have a considerable impact on the surgeon selection of the stem fixation mode. This suggests that the femoral fixation mode may be a suitable metric for quality improvement if patient factors are more likely to be prioritized in stem selection in the bundle environment.

The advantages of cementless fixation include shorter operative times and the potential for biologic osseointegration28,29. There has been a dramatic increase in the use of cementless femoral components in the United States, and the great majority of surgeons would consider a cementless stem to be their default choice for elective THA30. In 2012, a sample of >100,000 THAs from 174 hospitals in the United States found that 93% of implanted stems were cementless26. This trend toward use of cementless femoral components has occurred despite the excellent track record of cemented femoral fixation in multiple national registries, with favorable early and long-term revision rates when compared with cementless stems among elderly patients27,31-33.

The advantages of cemented fixation include lower risk of periprosthetic fracture, stem subsidence, or failure of osseointegration, particularly in elderly female patients with poor bone quality11,34-36. In a study of the Australian Orthopaedic Association National Joint Replacement Registry of patients who were >75 years of age and underwent a THA, Tanzer et al. found that the risk of revision in the first month postoperatively among elective cases was markedly higher with cementless stems compared with cemented stems (hazard ratio [HR], 8.82; p < 0.001)14. There have been reports of cardiopulmonary complications related to cement usage37,38; however, more recent studies have challenged these findings35,39.

We found that, for male patients undergoing THA, surgeons in mandatory CJR bundling areas were less likely to select cemented femoral fixation compared with surgeons not in a CJR bundling area. It is possible that perceived differences in the direct costs of cemented fixation influenced decision-making for patients who were not deemed to be at an elevated risk for fracture or implant-related complications. Prior analyses have found that cemented stems are cheaper, but additional costs of cement and cementing supplies in addition to extra operative time likely offset savings; differences in costs related to complications outweigh differences in direct costs40-42. We speculate that a preference for cementless stems among male patients in bundling MSAs may signal a surgeon decision-making process that is more attuned to the patient risk profile.

There were several limitations to this study. Our analysis relied on the information in the Medicare data set; data elements were limited to what was available and data could have been subject to coding errors. This analysis did not make adjusted comparisons of outcomes between cemented and uncemented groups because our focus was on the impact of the bundle on surgeon decision-making. The decision to cement or not is multifactorial and is likely dependent on variables not observable in this data set, making the comparisons of outcomes between groups challenging. Nonetheless, our approach allowed us to investigate surgeon selection of the stem fixation strategy, although information on the exact reasons why surgeons chose a particular fixation strategy was not available. Further study that directly examines surgeon decision-making is needed. Finally, our analysis focuses on patients with specified cement status. However, a comparison of patients with specified and unspecified cement codes indicate that the groups are similar in distribution according to sociodemographic and geographic characteristics.

In conclusion, in areas subject to the CMS mandatory CJR bundling policy, surgeons appear to be more risk-averse and are more likely to favor cemented femoral fixation for patients at risk for fracture or implant-related complications.

References

1. U.S. Centers for Medicare & Medicaid Services. Comprehensive Care for Joint Replacement model. Accessed 2020 Apr 5. https://innovation.cms.gov/innovation-models/cjr
2. Kurtz S, Ong K, Lau E, Mowat F, Halpern M. Projections of primary and revision hip and knee arthroplasty in the United States from 2005 to 2030. J Bone Joint Surg Am. 2007 Apr;89(4):780-5.
3. Greenwald AS, Bassano A, Wiggins S, Froimson MI. Alternative reimbursement models: bundled payment and beyond: AOA critical issues. J Bone Joint Surg Am. 2016 Jun 1;98(11):e45.
4. Dundon JM, Bosco J, Slover J, Yu S, Sayeed Y, Iorio R. Improvement in total joint replacement quality metrics: year one versus year three of the Bundled Payments for Care Improvement initiative. J Bone Joint Surg Am. 2016 Dec 7;98(23):1949-53.
5. Pelt CE, Anderson MB, Erickson JA, Gililland JM, Peters CL. Adding value to total joint arthroplasty care in an academic environment: the Utah experience. J Arthroplasty. 2018 Jun;33(6):1636-40. Epub 2018 Feb 10.
6. Pelt CE, Gililland JM, Erickson JA, Trimble DE, Anderson MB, Peters CL. Improving value in total joint arthroplasty: a comprehensive patient education and management program decreases discharge to post-acute care facilities and post-operative complications. J Arthroplasty. 2018 Jan;33(1):14-8. Epub 2017 Aug 19.
7. Iorio R, Clair AJ, Inneh IA, Slover JD, Bosco JA, Zuckerman JD. Early results of Medicare’s bundled payment initiative for a 90-day total joint arthroplasty episode of care. J Arthroplasty. 2016 Feb;31(2):343-50. Epub 2015 Sep 9.
8. Navathe AS, Troxel AB, Liao JM, Nan N, Zhu J, Zhong W, Emanuel EJ. Cost of joint replacement using bundled payment models. JAMA Intern Med. 2017 Feb 1;177(2):214-22.
9. Dummit LA, Kahvecioglu D, Marrufo G, Rajkumar R, Marshall J, Tan E, Press MJ, Flood S, Muldoon LD, Gu Q, Hassol A, Bott DM, Bassano A, Conway PH. Association between hospital participation in a Medicare bundled payment initiative and payments and quality outcomes for lower extremity joint replacement episodes. JAMA. 2016 Sep 27;316(12):1267-78.
10. Barnett ML, Wilcock A, McWilliams JM, Epstein AM, Joynt Maddox KE, Orav EJ, Grabowski DC, Mehrotra A. Two-year evaluation of mandatory bundled payments for joint replacement. N Engl J Med. 2019 Jan 17;380(3):252-62. Epub 2019 Jan 2.
11. Moerman S, Mathijssen NMC, Niesten DD, Riedijk R, Rijnberg WJ, Koëter S, Kremers van de Hei K, Tuinebreijer WE, Molenaar TL, Nelissen RGHH, Vochteloo AJH. More complications in uncemented compared to cemented hemiarthroplasty for displaced femoral neck fractures: a randomized controlled trial of 201 patients, with one year follow-up. BMC Musculoskelet Disord. 2017 Apr 21;18(1):169.
12. Veldman HD, Heyligers IC, Grimm B, Boymans TA. Cemented versus cementless hemiarthroplasty for a displaced fracture of the femoral neck: a systematic review and meta-analysis of current generation hip stems. Bone Joint J. 2017 Apr;99-B(4):421-31.
13. Grosso MG, Danoff JR, Padgett DE, Iorio R, Macaulay WB. The cemented unipolar prosthesis for the management of displaced femoral neck fractures in the dependent osteopenic elderly. J Arthroplasty. 2016 May;31(5):1040-6. Epub 2015 Dec 2.
14. Tanzer M, Graves SE, Peng A, Shimmin AJ. Is cemented or cementless femoral stem fixation more durable in patients older than 75 years of age? A comparison of the best-performing stems. Clin Orthop Relat Res. 2018 Jul;476(7):1428-37.
15. U.S. Centers for Medicare & Medicaid Services. Procedure-specific measure updates and specifications report hospital-level risk-standardized complication measure: elective primary total hip arthroplasty (THA) and/or total knee arthroplasty (TKA). 2018. Accessed 2020 Nov 13. https://www.qualitynet.org/files/5d0d3ada764be766b0104b90?filename=ProcSpec_Comp_AUS_Rpt_032818.pdf
16. Troelsen A, Malchau E, Sillesen N, Malchau H. A review of current fixation use and registry outcomes in total hip arthroplasty: the uncemented paradox. Clin Orthop Relat Res. 2013 Jul;471(7):2052-9. Epub 2013 Mar 29.
17. Elixhauser A, Steiner C, Harris DR, Coffey RM. Comorbidity measures for use with administrative data. Med Care. 1998 Jan;36(1):8-27.
18. Quan H, Sundararajan V, Halfon P, Fong A, Burnand B, Luthi JC, Saunders LD, Beck CA, Feasby TE, Ghali WA. Coding algorithms for defining comorbidities in ICD-9-CM and ICD-10 administrative data. Med Care. 2005 Nov;43(11):1130-9.
19. Hartman CW, Gilbert BJ, Paprosky WG. Gender issues in total hip arthroplasty: length, offset, and osteoporosis. Semin Arthroplasty. 2009;20(1):62-5.
20. Peacock M, Liu G, Carey M, Ambrosius W, Turner CH, Hui S, Johnston CC Jr. Bone mass and structure at the hip in men and women over the age of 60 years. Osteoporos Int. 1998;8(3):231-9.
21. Burwell SM. Setting value-based payment goals—HHS efforts to improve U.S. health care. N Engl J Med. 2015 Mar 5;372(10):897-9. Epub 2015 Jan 26.
22. Demontiero O, Vidal C, Duque G. Aging and bone loss: new insights for the clinician. Ther Adv Musculoskelet Dis. 2012 Apr;4(2):61-76.
23. Cummings SR, Melton LJ. Epidemiology and outcomes of osteoporotic fractures. Lancet. 2002 May 18;359(9319):1761-7.
24. Garnero P, Sornay-Rendu E, Chapuy MC, Delmas PD. Increased bone turnover in late postmenopausal women is a major determinant of osteoporosis. J Bone Miner Res. 1996 Mar;11(3):337-49.
25. Du Y, Zhao LJ, Xu Q, Wu KH, Deng HW. Socioeconomic status and bone mineral density in adults by race/ethnicity and gender: the Louisiana Osteoporosis Study. Osteoporos Int. 2017 May;28(5):1699-709. Epub 2017 Feb 24.
26. Lehil MS, Bozic KJ. Trends in total hip arthroplasty implant utilization in the United States. J Arthroplasty. 2014 Oct;29(10):1915-8. Epub 2014 May 28.
27. Karrholm J. Swedish Hip Arthroplasty Register. Annual report 2018. 2019. Accessed 2020 Oct 28. https://registercentrum.blob.core.windows.net/shpr/r/Arsrapport_2018_Hoftprotes_ENG_26mars_Final-rJepCXNsLI.pdf
28. Khanuja HS, Vakil JJ, Goddard MS, Mont MA. Cementless femoral fixation in total hip arthroplasty. J Bone Joint Surg Am. 2011 Mar 2;93(5):500-9.
29. Ahn J, Man LX, Park S, Sodl JF, Esterhai JL. Systematic review of cemented and uncemented hemiarthroplasty outcomes for femoral neck fractures. Clin Orthop Relat Res. 2008 Oct;466(10):2513-8. Epub 2008 Jul 24.
30. Berry DJ, Bozic KJ. Current practice patterns in primary hip and knee arthroplasty among members of the American Association of Hip and Knee Surgeons. J Arthroplasty. 2010 Sep;25(6)(Suppl):2-4. Epub 2010 Jul 1.
31. McKie J. The New Zealand Joint Registry. 20-year report. 2019. Accessed 2020 Oct 28. https://nzoa.org.nz/nzoa-joint-registry
32. Powers-Freeling J. The National Joint Registry 16th annual report 2019. London: National Joint Registry; 2019.
33. Graves S; Australian Orthopaedic Association National Joint Replacement Registry. 20th annual report. 2019. Accessed 2020 Oct 28. https://aoanjrr.sahmri.com/annual-reports-2019
34. Rogmark C, Fenstad AM, Leonardsson O, Engesæter LB, Kärrholm J, Furnes O, Garellick G, Gjertsen JE. Posterior approach and uncemented stems increases the risk of reoperation after hemiarthroplasties in elderly hip fracture patients. Acta Orthop. 2014 Feb;85(1):18-25. Epub 2014 Jan 24.
35. Taylor F, Wright M, Zhu M. Hemiarthroplasty of the hip with and without cement: a randomized clinical trial. J Bone Joint Surg Am. 2012 Apr 4;94(7):577-83.
36. Langslet E, Frihagen F, Opland V, Madsen JE, Nordsletten L, Figved W. Cemented versus uncemented hemiarthroplasty for displaced femoral neck fractures: 5-year followup of a randomized trial. Clin Orthop Relat Res. 2014 Apr;472(4):1291-9. Epub 2013 Oct 1.
37. Francis CW, Marder VJ, Evarts CM. Lower risk of thromboembolic disease after total hip replacement with non-cemented than with cemented prostheses. Lancet. 1986 Apr 5;1(8484):769-71.
38. Ries MD, Lynch F, Rauscher LA, Richman J, Mick C, Gomez M. Pulmonary function during and after total hip replacement. Findings in patients who have insertion of a femoral component with and without cement. J Bone Joint Surg Am. 1993 Apr;75(4):581-7.
39. Miyamoto S, Nakamura J, Iida S, Shigemura T, Kishida S, Abe I, Takeshita M, Harada Y, Orita S, Ohtori S. Intraoperative blood pressure changes during cemented versus uncemented bipolar hemiarthroplasty for displaced femoral neck fracture: a multi-center cohort study: the effect of bone cement for bipolar hemiarthroplasty in elderly patients. Arch Orthop Trauma Surg. 2017 Apr;137(4):523-9. Epub 2017 Feb 17.
40. Blythe R, O’Gorman PM, Crawford RW, Feenan R, Hatton A, Whitehouse SL, Graves N. Fixation method for hip arthroplasty stem following hip fracture: a population-level cost-effectiveness analysis. J Arthroplasty. 2020 Jun;35(6):1614-21. Epub 2020 Feb 8.
41. Pennington M, Grieve R, Sekhon JS, Gregg P, Black N, van der Meulen JH. Cemented, cementless, and hybrid prostheses for total hip replacement: cost effectiveness analysis. BMJ. 2013 Feb 27;346:f1026.
42. Fawsitt CG, Thom HHZ, Hunt LP, Nemes S, Blom AW, Welton NJ, Hollingworth W, López-López JA, Beswick AD, Burston A, Rolfson O, Garellick G, Marques EMR. Choice of prosthetic implant combinations in total hip replacement: cost-effectiveness analysis using UK and Swedish hip joint registries data. Value Health. 2019 Mar;22(3):303-12. Epub 2018 Nov 2.

Supplemental Digital Content

Copyright © 2020 The Authors. Published by The Journal of Bone and Joint Surgery, Incorporated. All rights reserved.