A Validated Pre-operative Risk Prediction Tool for Extended Inpatient Length of Stay Following Primary Total Hip or Knee Arthroplasty.

BACKGROUND: As value-based reimbursement models mature, understanding the potential trade-off between inpatient lengths of stay and complications or need for costly postacute care becomes more pressing. Understanding and predicting a patient's expected baseline length of stay may help providers understand how best to decide optimal discharge timing for high-risk total joint arthroplasty (TJA) patients. METHODS: A retrospective review was conducted of 37,406 primary total hip (17,134, 46%) and knee (20,272, 54%) arthroplasties performed at two high-volume, geographically diverse, tertiary health systems during the study period. Patients were stratified by 3 binary outcomes for extended inpatient length of stay: 72 + hours (29%), 4 + days (11%), or 5 + days (5%). The predictive ability of over 50 sociodemographic/comorbidity variables was tested. Multivariable logistic regression models were created using institution #1 (derivation), with accuracy tested using the cohort from institution #2 (validation). RESULTS: During the study period, patients underwent an extended length of stay with a decreasing frequency over time, with privately insured patients having a significantly shorter length of stay relative to those with Medicare (1.9 versus 2.3 days, P < .0001). Extended stay patients also had significantly higher 90-day readmission rates (P < .0001), even when excluding those discharged to postacute care (P < .01). Multivariable logistic regression models created from the training cohort demonstrated excellent accuracy (area under the curve (AUC): 0.755, 0.783, 0.810) and performed well under external validation (AUC: 0.719, 0.743, 0.763). Many important variables were common to all 3 models, including age, sex, American Society of Anesthesiologists (ASA) score, body mass index, marital status, bilateral case, insurance type, and 13 comorbidities. DISCUSSION: An online, freely available, preoperative clinical decision tool accurately predicts risk of extended inpatient length of stay after TJA. Many risk factors are potentially modifiable, and these validated tools may help guide clinicians in preoperative patient counseling, medical optimization, and understanding optimal discharge timing.

A Preoperative Risk Prediction Tool for Discharge to a Skilled Nursing or Rehabilitation Facility After Total Joint Arthroplasty.

BACKGROUND: Discharge to rehabilitation or a skilled nursing facility (SNF) after total joint arthroplasty remains a primary driver of cost excess for bundled payments. An accurate preoperative risk prediction tool would help providers and health systems identify and modulate perioperative care for higher risk individuals and serve as a vital tool in preoperative clinic as part of shared decision-making regarding the risks/benefits of surgery. METHODS: A total of 10,155 primary total knee (5,570, 55%) and hip (4,585, 45%) arthroplasties performed between June 2013 and January 2018 at a single institution were reviewed. The predictive ability of 45 variables for discharge location (SNF/rehab vs home) was tested, including preoperative sociodemographic factors, intraoperative metrics, postoperative labs, as well as 30 Elixhauser comorbidities. Parameters surviving selection were included in a multivariable logistic regression model, which was calibrated using 20,000 bootstrapped samples. RESULTS: A total of 1786 (17.6%) cases were discharged to a SNF/rehab, and a multivariable logistic regression model demonstrated excellent predictive accuracy (area under the receiver operator characteristic curve: 0.824) despite requiring only 9 preoperative variables: age, partner status, the American Society of Anesthesiologists score, body mass index, gender, neurologic disease, electrolyte disorder, paralysis, and pulmonary circulation disorder. Notably, this model was independent of surgery (knee vs hip). Internal validation showed no loss of accuracy (area under the receiver operator characteristic curve: 0.8216, mean squared error: 0.0004) after bias correction for overfitting, and the model was incorporated into a readily available, online prediction tool for easy clinical use. CONCLUSION: This convenient, interactive tool for estimating likelihood of discharge to a SNF/rehab achieves excellent accuracy using exclusively preoperative factors. These should form the basis for improved reimbursement legislation adjusting for patient risk, ensuring no disparities in access arise for vulnerable populations. LEVEL OF EVIDENCE: III.

All-Polyethylene Tibia: An Opportunity for Value-Based Care in Bundled Reimbursement Initiatives.

Surgeons play a critical role in making cost-effective decisions that maintain high-quality patient outcomes, which is the current focus of the Centers for Medicare & Medicaid Services. All-polyethylene tibial (APT) components often cost less during total knee arthroplasty (TKA). The authors sought to determine the relative cost savings of APT, as well as their effect on 90-day quality outcome metrics. This was a retrospective review of primary TKAs performed at a single tertiary referral center participating in the Comprehensive Care for Joint Replacement model, by 2 surgeons, from 2015 to 2017. Patient demographic data and direct hospital costs were collected, and patients were stratified by APTs vs metal-backed components. Univariable and multivariable analyses were performed for all outcome metrics. A total of 188 primary TKAs were included (92 APT, 96 metal-backed). Patients receiving APT components were older (P<.001) and had a lower body mass index (P<.001), but there was no difference in sex or American Society of Anesthesiologists score between groups. Operative time was significantly less (mean, 13 minutes) and direct surgery costs were significantly lower for APTs (P<.001). A multivariable regression model for surgical costs demonstrated significant savings (P<.001), and total hospital cost demonstrated a 6.2% average savings with APT. There was no difference in 90-day emergency department visits or re-admissions. This study demonstrates that the use of an APT is able to significantly affect not only the surgical cost but also the total hospital admission cost while maintaining equivalent 90-day outcome metrics. Strategies like this should be considered in appropriately selected patients as the incidence of TKA continues to expand. [Orthopedics. 2021;44(1):e114-e118.].

Roadmap for Transforming Preoperative Assessment to Preoperative Optimization.

Preoperative assessment typically equates to evaluating and accepting the presenting condition of the patient (unless extreme) and commonly occurs only a few days before the planned surgery. While this timing enables a preoperative history and examination and mitigates unexpected findings on the day of surgery that may delay throughput, it does not allow for meaningful preoperative management of modifiable medical conditions. Evidence is limited regarding how best to balance efforts to mitigate modifiable risk factors versus the timing of surgery. Furthermore, while the concept of preoperative risk modification is not novel, evidence is lacking for successful and sustained implementation of such an interdisciplinary, collaborative program. A better understanding of perioperative care coordination and, specifically, implementing a preoperative preparation process can enhance the value of surgery and surgical population health. In this article, we describe the implementation of a collaborative preoperative clinic with the primary goal of improving patient outcomes.

Should Medical Severity-Diagnosis Related Group Classification Be Utilized for Reimbursement? An Analysis of Elixhauser Comorbidities and Cost of Care.

BACKGROUND: The Center for Medicare and Medicaid Services (CMS) classifies reimbursement for total hip arthroplasty (THA) and total knee arthroplasty (TKA) based on Medical Severity-Diagnosis Related Groups (MS-DRGs) 469 (with major complication/comorbidity) and 470 (without major complication/comorbidity). The validated Elixhauser comorbidity index includes 31 variables that may be associated with MS-DRG 469. However, we hypothesized that these comorbidities may not be the most predictive of increased cost of care. METHODS: Elixhauser comorbidities were retrospectively examined for 1243 TKAs and 897 THAs from 2013 to 2017 at a single center. Comorbidities were investigated in univariable analysis and significant variables associated with MS-DRG 469, and cost of care was further investigated in a multivariable regression to determine which were most predictive of the increased complexity classification assigned by CMS vs true increased cost of care. RESULTS: Thirty-nine patients (1.8%) were classified as MS-DRG 469. Univariable and multivariable logistic analysis revealed that coagulopathy, electrolyte disorders, neurodegenerative disorders, and psychosis were significantly associated with an increased complexity classification. These 4 comorbidities were also associated with increased cost of care; however, 13 additional comorbidities were also predictive of increased cost but not MS-DRG classification. CONCLUSIONS: Patient comorbidities have been shown to increase complications and cost of care for arthroplasty patients. To date, however, the only risk adjustment provided has been the 469 DRG code. This study demonstrates little correlation to the current system with the most expensive diagnoses. Consequently, an expansion of the current risk adjustment system for THA and TKA provided by CMS appears greatly needed.

Predicting Inpatient Dissatisfaction Following Total Joint Arthroplasty: An Analysis of 3,593 Hospital Consumer Assessment of Healthcare Providers and Systems Survey Responses.

BACKGROUND: The Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) survey, created by the Centers for Medicare and Medicaid, is directly tied to hospital reimbursement. The purpose of this study is to identify factors that are predictive HCAHPS survey responses following primary hip and knee arthroplasty. METHODS: Prospectively collected HCAHPS responses from patients undergoing elective hip and knee arthroplasty between January 2013 and October 2017 at our institution were analyzed. Patient age, gender, race, marital status, body mass index, American Society of Anesthesiologists score, preoperative pain score, smoking status, alcohol use, illegal drug use, socioeconomic quartile, insurance type, procedure type, hospital type (academic vs community), distance to medical center, length of stay (LOS), and discharge disposition were obtained and correlated with HCAHPS inpatient satisfaction scores. RESULTS: Responses from 3593 patients were obtained: 1546 total hip arthroplasties, 1899 total knee arthroplasties, and 148 unicompartmental knee arthroplasties. Mean overall HCAHPS score was 79.2. Women had lower inpatient satisfaction than men (77.6 vs 81.6, P < .001). Alcohol consumers had lower inpatient satisfaction than abstainers (77.7 vs 81.6, P < .001). Inpatient satisfaction varied by socioeconomic quartile (P < .001) with patients in the highest quartile having lower satisfaction than patients in all other quartiles (P < .001). Patients discharged to a facility had lower inpatient satisfaction than those discharged home (71.2 vs 80.2, P < .001). An inverse correlation between inpatient satisfaction and LOS (r = -0.19, P < .001) and a direct correlation between satisfaction and distance to medical center (r = 0.06, P < .001) were seen. CONCLUSION: Patients more likely to report lower levels of inpatient satisfaction after total joint arthroplasty are female, affluent, and alcohol consumers, who are discharged to postacute care facilities. Inpatient satisfaction was inversely correlated with LOS and positively correlated with distance from patient home to medical center. These findings provide targets for improvements in TJA inpatient care.

Preoperative Optimization Checklists Within the Comprehensive Care for Joint Replacement Bundle Have Not Decreased Hospital Returns for Total Knee Arthroplasty.

BACKGROUND: The Comprehensive Care for Joint Replacement (CJR) model has resulted in the evolution of preoperative optimization programs to decrease costs and hospital returns. At the investigating institution, one center was not within the CJR bundle and has dedicated fewer resources to this effort. The remaining centers have adopted an 11 metric checklist designed to identify and mitigate modifiable preoperative risks. We hypothesized that this checklist would improve postoperative metrics that impact costs for total knee arthroplasty (TKA) patients eligible for participation in CJR. METHODS: Patients undergoing TKA from 2014 to 2018 were retrospectively reviewed. Only patients with eligible participation in CJR were included. Outcome variables including length of stay, disposition, 90-day emergency department visits, and hospital readmissions were explored. Analysis was performed to determine differences in outcomes between CJR participating and non-CJR participating hospitals within the healthcare system. RESULTS: In total, 2308 TKA patients including 1564 from a CJR participating center and 744 from a non-CJR center were analyzed. There was no significant difference in patient age or gender. Patients at the non-CJR hospital had significantly higher body mass index (P < .001) and American Society of Anesthesiologists scores (P < .001), while those in the CJR network had fewer skilled nursing facility discharges (P = .028) and shorter length of stay (P < .001). However, there was no reduction in 90-day emergency department visits or readmissions. CONCLUSION: The resources utilized at CJR participating hospitals, including patient optimization checklists, did not effectively alter patient outcomes following discharge. Likely, a checklist alone is insufficient for risk mitigation and detailed optimization protocols for modifiable risk factors must be investigated.

Utilization of an Electronic Patient Portal Following Total Joint Arthroplasty Does Not Decrease Readmissions.

BACKGROUND: At the investigating institution, an electronic messaging portal (MyChart) allows patients to directly communicate with their healthcare provider. As reimbursement models evolve, there is an increasing effort to decrease 90-day hospital resource utilization and patient returns, and secure messaging portals have been proposed as one way to achieve this goal. We sought to determine which patients utilize this portal, and to determine the impact of secure messaging on emergency department (ED) visits and readmissions within 90 days postoperatively. METHODS: The institutional database was used to analyze 6426 procedures including 3297 primary total knee and 3129 primary total hip arthroplasties. Patient demographics, comorbidities, and secure communication activity status were recorded. Subsequently, statistical analysis was performed to determine which patients utilized MyChart, as well as to correlate patient outcomes to the utilization of secure messaging portals. RESULTS: Active MyChart users were significantly more likely to be young, healthy (American Society of Anesthesiologists 1 or 2), Caucasian, married, employed, have private insurance, and be discharged to home. Decreased utilization was seen in patients who were unhealthy (American Society of Anesthesiologists 3 or 4), were African American, unmarried, unemployed, had Medicare or Medicaid insurance, and were discharged to a skilled nursing facility; these characteristics were also independent significant risks for returning to the ED. Active MyChart status was not significantly associated with 90-day ED return (P = .781) or readmission (P = .512). However, if multiple messages to providers were sent, and the provider response rate was <75%, patients had significantly more readmissions (P = .004). CONCLUSION: Primary total joint arthroplasty patients who were at high risk for ED returns were less likely to utilize MyChart. However, MyChart use did not decrease the 90-day rate of return to the ED or readmissions. A low provider response rate to the secure messages may lead to increased resource utilization in patients using secure messaging as their preferred communication tool. Alternative means of communication with the most vulnerable patients must be investigated to effectively decrease postoperative complications and resource utilization.

Predicting Costs Exceeding Bundled Payment Targets for Total Joint Arthroplasty.

BACKGROUND: The Center for Medicare and Medicaid Services has instituted bundled reimbursement models for total joint arthroplasty (TJA), which includes target prices for each procedure. Some patients exceed these targets; however, currently there are no tools to accurately predict this preoperatively. We hypothesized that a validated comorbidity index combined with patient demographics would adequately predict excess cost-of-care prior to hospitalization. METHODS: Two thousand eighty-four primary unilateral TJAs performed at a single tertiary center were retrospectively examined. Data were extracted from medical records and a predictive model was built from 30 comorbidities and 7 patient demographic factors (age, gender, race, body mass index, American Society of Anesthesiologists score, smoking status, and marital status). Following parameter selection, a final multivariable model was created, with a corresponding nomogram for interactive visualization of probability for excess cost. RESULTS: Six hundred twelve patients (29%) had cost-of-care exceeding the target price. The final model demonstrated adequate predictive discrimination for cost-of-care exceeding the target price (area under the receiver operator characteristic curve: 0.747). Factors associated with excess cost included age, gender, marital status, American Society of Anesthesiologists score, body mass index, and race, as well as 7 Elixhauser comorbidities (alcohol use, rheumatoid arthritis, diabetes, electrolyte disorders, neurodegenerative disorders, psychoses, and pulmonary circulatory disorders). CONCLUSION: A novel patient model composed of a subset of validated comorbidities and demographic variables provides adequate discrimination in predicting excess cost within bundled payment models for TJA. This not only helps identify patients who would benefit from preoperative optimization, but also provides evidence for modification of future bundled reimbursement models to adjust for nonmodifiable risk factors.

Skilled Nursing Facilities After Total Knee Arthroplasty: The Time for Selective Partnerships Is Now!

BACKGROUND: Bundled payment initiatives for total knee arthroplasty (TKA) patients are dramatically impacted by discharges to skilled nursing facilities (SNFs), making target prices set by the Center for Medicare and Medicaid Services difficult to achieve. However, we hypothesized that a granular examination of SNF discharges would reveal that some may disproportionately increase costs compared to others. METHODS: The institutional database was retrospectively queried for primary TKA patients under bundled payment initiatives. The 4 most common SNFs utilized by our patient population (A, B, C, and D) were investigated for length of stay, cost of care, and whether the overall target price for the episode of care (EOC) was reached. RESULTS: In total, 1223 TKA patients were analyzed, with 378 (30.9%) discharged to an SNF and 246 patients selecting one of the 4 most common SNFs (A: 198, B: 21, C: 15, D: 12). Each SNF represented a significant fiscal portion of the total EOC; however, SNF D had significantly longer length of stay (21 vs 13 days, P < .001) and cost of care ($11,805 vs $6015, P < .001) relative to the others, resulting in no EOC under the target price. SNF costs >24.6% of the total EOC were predictive of exceeding the target price. CONCLUSION: Bundled payment models are significantly impacted by SNF disposition; however, select facilities disproportionately impact this system. In order to maintain free patient selection for disposition, post-acute care facilities must be held accountable for controlling cost, or a separate bundled payment provided.

Preoperative Patient Profile in Total Hip and Knee Arthroplasty: Predictive of Increased Medicare Payments in a Bundled Payment Model.

BACKGROUND: The shift toward value-based bundled payment models in total joint arthroplasty highlights the need for identification of modifiable risk factors for increased spending as well as opportunities to mitigate perioperative treatment of chronic disease. The purpose of this study was to identify preoperative comorbidities that result in an increased financial burden using institutional data at a single institution. METHODS: We conducted a retrospective review of total joint arthroplasty patients and collected payment data from the Center for Medicare and Medicaid Services for each patient up to 90 days after surgery in accordance with the regulations of the Comprehensive Care for Joint Replacement initiative. Statistical analysis and comparison of preoperative profile and Medicare payments as a surrogate for cost were completed. RESULTS: Six hundred ninety-four patients were identified over a 4-year time period who underwent surgery before adoption of the Comprehensive Care for Joint Replacement but that met criteria for inclusion. The median total payment per patient episode of care was $20,048. Preoperative diagnosis of alcoholism, anemia, diabetes, and obesity was found to have a statistically significant effect on total payments. The model predicted a geometric mean increase from $1425 to $9308 for patients bearing these comorbidities. CONCLUSION: With Medicare payments as a surrogate for cost, we demonstrate that specific patient comorbidities and a cumulative increase in comorbidities predict increased costs. This study was based on institutional data rather than administrative data to gain actionable information on an institutional level and highlight potential flaws in research based on administrative data.

Conversion vs Primary Total Hip Arthroplasty: Increased Cost of Care and Perioperative Complications.

BACKGROUND: With the increasing incidence of hip fractures and hip preservation surgeries, there has been a concomitant rise in the number of conversion total hip arthroplasties (THAs) performed. Prior studies have shown higher complication rates in conversion THA. However, there is a paucity of data showing differences in cost between these 2 procedures. Currently, the Center for Medicare and Medicaid Services bundles primary and conversion THA in the same Medicare Severity-Diagnosis Related Group for hospital reimbursement. More evidence is needed to support the reclassification of conversion THA. METHODS: The cohort provided by the institutional database included 163 conversion THAs between January 1, 2012 and December 31, 2015. Intraoperative complications, estimated blood loss, operative time, postoperative complications, and perioperative cost data were analyzed for 163 primary THA patients matched to the conversion THA cohort. RESULTS: Compared with primary THA, conversion THA had significantly (P < .05) greater cost for direct labor, other direct costs, intermediate nursing services, other diagnostic/therapy, surgery services, physical/occupational/speech therapy, radiology, laboratories, blood, medical/surgical supply, and total direct costs. In addition, the conversion THA group had significantly greater operative times, estimated blood loss, length of stay, intraoperative complications, and postoperative complications. CONCLUSION: Conversion THA, as compared with primary THA, is associated with greater costs (approximately 19% greater), increased surgical times, and perioperative complications. To prevent these additional expenses from creating patient selection bias and a barrier to care, the conversion THA Medicare Severity-Diagnosis Related Group should be reclassified, or modifiers created.

Inpatient Consults and Complications During Primary Total Joint Arthroplasty in a Bundled Care Model.

BACKGROUND: The Centers for Medicare and Medicaid Services (CMS) are implementing changes in hospital reimbursement models for total joint arthroplasty (TJA), moving to value-based bundled payments from the fee-for-service model. The purpose of this study is to identify consults and complications during the perioperative period that increase financial burden. METHODS: We combined CMS payment data for inpatient, professional, and postoperative with retrospective review of patients undergoing primary TJA and developed profiles of patients included in the Comprehensive Care for Joint Replacement bundle undergoing TJA. Statistical comparison of episode inpatient events and payments was conducted. Multiple regression analysis was adjusted for length of stay, disposition, and Charlson-Deyo comorbidity profile. RESULTS: Median total payment was $21,577.36, which exceeded the median bundle target payment of $20,625.00. Adjusted analyses showed that psychiatry consults (increase of $73,123.32; P < .001), internal medicine consults ($5789.38; P ≤ .001), pulmonary embolism ($35,273.68; P < .001), intensive care unit admission ($14,078.37; P < .001), and deep vein thrombosis ($9471.26; P = .019) resulted in increased payments using multivariate analysis adjusted for length of stay, Charlson-Deyo comorbidities, and discharge disposition. CONCLUSION: Patients with inpatient complications such as pulmonary embolism and/or deep vein thrombosis, intensive care unit admission, and medical/psychiatric consultation exceeded the CMS target. Although study results showed typical complication rates, acute inpatient consultation significantly increased utilization beyond the CMS target even when adjusted for length of stay, patient comorbidities, and discharge. Needed medical care should continue to be a priority for inpatients, and allowance for individual outliers should be considered in policy discussions.

Modeling the Potential Economic Impact of the Medicare Comprehensive Care for Joint Replacement Episode-Based Payment Model.

BACKGROUND: The Medicare program has initiated Comprehensive Care for Joint Replacement (CJR), a bundled payment mandate for lower extremity joint replacements. We sought to determine the degree to which hospitals will invest in care redesign in response to CJR, and to project its economic impacts. METHODS: We defined 4 potential hospital management strategies to address CJR: no action, light care management, heavy care management, and heavy care management with contracting. For each of 798 hospitals included in CJR, we used hospital-specific volume, cost, and quality data to determine the hospital's economically dominant strategy. We aggregated data to assess the percentage of hospitals pursuing each strategy; savings to the health care system; and costs and percentages of CJR-derived revenues gained or lost for Medicare, hospitals, and postacute care facilities. RESULTS: In the model, 83.1% of hospitals (range 55.0%-100.0%) were expected to take no action in response to CJR, and 16.1% of hospitals (range 0.0%-45.0%) were expected to pursue heavy care management with contracting. Overall, CJR is projected to reduce health care expenditures by 0.5% (range 0.0%-4.1%) or $14 million (range $0-$119 million). Medicare is expected to save 2.2% (range 2.2%-2.2%), hospitals are projected to lose 3.7% (range 4.7% loss to 3.8% gain), and postacute care facilities are expected to lose 6.5% (range 0.0%-12.8%). Hospital administrative costs are projected to increase by $63 million (range $0-$148 million). CONCLUSION: CJR is projected to have a negligible impact on total health care expenditures for lower extremity joint replacements. Further research will be required to assess the actual care management strategies adopted by CJR hospitals.

Current Evidence Does Not Support Medicare's 3-Day Rule in Primary Total Joint Arthroplasty.

Patients who undergo total joint arthroplasty and are destined for discharge to an extended-care facility--particularly Medicare beneficiaries--are required to have an inpatient stay of at least 3 consecutive days. The primary objective of this study was to explore the effect of this policy on length of stay. Secondary outcomes were 30-day readmission rate and inpatient rehabilitation gains. We retrospectively reviewed 284 consecutive cases of patients who underwent primary total hip or knee arthroplasty and were discharged to an extended-care facility. Based on readiness-for-discharge criteria, delaying discharge until postoperative day 3 increased length of stay by 1.08 days (P < .001) and had no effect on risk for 30-day readmission (P = .073). Although rehabilitation status improved with stays past discharge readiness (P = .038), the gains were not clinically sufficient to affect discharge destination. This study calls into question the validity of Medicare's 3-day rule in primary total joint arthroplasty. Larger, prospective, multicenter studies are needed to confirm these findings.

Medicare's 3-Day Rule: Time for a Rethink.

A pilot study was undertaken to examine the impact of Medicare's 3-day rule on length of stay (LOS). One hundred consecutive patients who underwent primary total joint arthroplasty and were discharged to extended care facilities were retrospectively reviewed. Based on readiness for discharge criteria, delaying discharge until the third postoperative day increased LOS by 1.1 days (P<0.001). 60.6% of patients were ready for discharge by the second postoperative day, none of whom required re-admission within 30 days of discharge. There were no rehabilitation gains by staying an additional hospital day beyond readiness for discharge (P=0.092). This pilot study calls into question the value of Medicare's 3-day rule and demonstrates the feasibility and need for further research to address this seemingly antiquated policy.

Preoperative pain level and patient expectation predict hospital length of stay after total hip arthroplasty.

The purpose of this study was to identify preoperative predictors of length of stay after primary total hip arthroplasty in a patient population reflecting current trends toward shorter hospitalization and using readily obtainable factors that do not require scoring systems. A retrospective review of 112 consecutive patients was performed. High preoperative pain level and patient expectation of discharge to extended care facilities (ECFs) were the only significant multivariable predictors of hospitalization extending beyond 2 days (P=0.001 and P<0.001 respectively). Patient expectation remained significant after adjusting for Medicare's 3-day requirement for discharge to ECFs (P<0.001). The study was adequately powered to analyze the variables in the multivariable logistic regression model, which had a concordance index of 0.857.

Unicompartmental knee arthroplasty and total knee arthroplasty among Medicare beneficiaries, 2000 to 2009.

BACKGROUND: Unicompartmental knee arthroplasty is a less-invasive alternative to total knee arthroplasty for patients with arthritis affecting only the medial or lateral compartment. However, little is known about recent trends in the use of these procedures and the associated outcomes among older patients. METHODS: With use of a nationally representative 5% sample of Medicare beneficiaries who were sixty-five years of age or older and who had undergone either unilateral unicompartmental knee arthroplasty or unilateral total knee arthroplasty from 2000 to 2009, we assessed trends in the use of unicompartmental and total knee arthroplasty, associated durations of hospital stay, and postoperative outcomes. The outcome measures were the rates of implant revision or removal within five years and the rates of periprosthetic infection, thromboembolic events, myocardial infarction, and all-cause mortality within one year. We conducted Kaplan-Meier analyses to assess the cumulative incidence of unadjusted outcomes and used Cox proportional-hazards regression to understand the relative risks of the outcomes for each procedure. RESULTS: A total of 68,603 patients underwent unilateral total knee arthroplasty (n = 65,505) or unilateral unicompartmental knee arthroplasty (n = 3098) from 2000 to 2009. The mean age was seventy-five years; 34% of the patients were men, and 92% were white. The procedure rate was twenty-one times higher for total knee arthroplasty (597 per 100,000 person-years) than unicompartmental knee arthroplasty (twenty-nine per 100,000 person-years). The use of total knee arthroplasty increased 1.7-fold, and the use of unicompartmental knee arthroplasty increased 6.2-fold. The mean length of stay (and standard deviation [SD]) was 3.9 ± 2.1 days for total knee arthroplasty and 2.4 ± 1.7 days for unicompartmental knee arthroplasty. The five-year revision rate was 3.7% for total knee arthroplasty and 8.0% for unicompartmental knee arthroplasty. After multivariable adjustment, the risk of revision remained 2.4 times higher for unicompartmental knee arthroplasty than for total knee arthroplasty (95% confidence interval [CI] = 2.03 to 2.83). After multivariable adjustment, patients who underwent unicompartmental knee arthroplasty had no significant differential one-year risk of infection (adjusted hazard ratio [HR] = 0.74; 95% CI = 0.55 to 1.01), thromboembolic events (adjusted HR =0.86; 95% CI = 0.57 to 1.29), or mortality (adjusted HR = 0.75; 95% CI = 0.50 to 1.11). CONCLUSIONS: Although unicompartmental knee arthroplasty accounted for only 4.5% of the unilateral knee replacements among Medicare beneficiaries, the use of this procedure has increased dramatically. Compared with those who had total knee arthroplasty, patients who underwent unicompartmental knee arthroplasty had higher revision rates but shorter durations of stay and tended to have lower rates of perioperative complications. These findings need to be confirmed by studies that incorporate detailed clinical information.

Simultaneous vs staged bilateral total knee arthroplasty among Medicare beneficiaries, 2000-2009.

Simultaneous bilateral total knee arthroplasty (TKA) reportedly has higher postoperative complication rates than staged procedures, but little is known about recent trends and outcomes among Medicare patients. In a 5% national sample of Medicare beneficiaries older than 65 years, we identified 83,441 patients who underwent elective TKA between 2000 and 2009 and compared patients undergoing simultaneous bilateral TKA (n=4519) to staged TKA (n=3788). Use of simultaneous TKA did not change over time (3 in 10,000), but use of staged TKA increased three-fold from 1.4 to 4.4 in 10,000 person-years. We assessed length of stay; 5-year risk of revision; periprocedural (i.e., 90-day) risk of infection; hospitalization for venous thromboembolism (VTE) and myocardial infarction (MI); and death using Kaplan-Meier methods. Simultaneous TKA had higher 90-day risk of death (0.7% vs. 0.3%, P=0.02), VTE (0.9% vs. 0.5%, P=0.07), and MI (0.5% vs. 0.2%, P=0.02). Infection and revision rates were similar between the two groups.