Should Medicare Remove Total Knee Arthroplasty From Its Inpatient Only List? A Total Knee Arthroplasty Is Not a Partial Knee Arthroplasty

Should Chronological Age be a Consideration in Patients Undergoing Elective Primary Total Knee Arthroplasty?

BACKGROUND

The optimal time for total knee arthroplasty (TKA) requires a balance between patient disability and health state to minimize complications. While chronological age has not been shown to be predictive of complications in elective surgical patients, there is a point beyond which even optimized elderly patients would be at increased risk for complications. The purpose of this study was to examine the impact of chronological age on complications following primary TKA.

METHODS

Using an administrative database, the records of 2,129,191 patients undergoing elective unilateral TKA between 2006 and 2021 were reviewed. The primary outcomes of interest were cardiac and pulmonary complications, and their relationship to the Charlson-Deyo Comorbidity Index (CDI) and chronological age. Secondary outcomes included risk of renal, neurologic, infection, and intensive care utilization postoperatively. The results were analyzed using a graphical method. The impact of chronological age as a modifier of overall risk for complications was modeled as a continuous variable. An age cutoff threshold of 80 years was also assigned for clinical convenience.

RESULTS

The risk of complications correlated more closely to the CDI (odds ratio (OR) 1.37 to 2.1) than chronological age (OR 1.0 to 1.1) across the various complications [Table 1. However, beyond age 80 years, the risks of cardiac, pulmonary, renal, and cerebrovascular complications were significantly increased for all CDI categories (OR 1.73 to 3.40) compared to patients below age 80 years [Table 2] [Figures 1A and 1B].

CONCLUSIONS

Chronologic age can impact the risk of complications even in well-optimized elderly patients undergoing primary TKA. As arthroplasty continues to transition to outpatient settings and inpatient denials increase, these results can help patients, physicians, and payors mitigate risk while optimizing the allocation of resources.

Patient Designation Prior to Total Knee Arthroplasty: How Can Preoperative Variables Impact Postoperative Status?

BACKGROUND

Removal of total knee arthroplasty (TKA) from the inpatient only list has led to a greater focus on outpatient (OP) procedures. However, the impact of OP-centered models in at-risk patients is unclear. Therefore, the current analysis investigated the effect of conversion from OP to inpatient (IP) status on postoperative outcomes and determined which factors put patients at risk for status change postoperatively.

METHODS

We retrospectively reviewed all patients who underwent a primary TKA at our institution between January 2, 2018, and April 26, 2022. All patients included were originally scheduled for OP surgery and were separated based on conversion to IP status postoperatively. Multiple regression analyses were used to determine the significance of all perioperative variables. Modeling via binary logistic regressions was used to determine factors predictive of status conversion.

RESULTS

Of the 2,313 patients originally designated for OP TKA, 627 (27.1%) required a stay of 2 midnights or longer. Patients in the IP group had significantly higher facility discharge rates (P < .001) compared to the OP group. Factors predictive of conversion included age of 65 years and older (P < .001), women (P < .001), arriving at the postanesthesia care unit after 12 pm (P < .001), body mass index greater than 30 (P = .004), and Charlson Comorbidity Index of 4 and higher (P = .004). Being the first case of the day (P < .001) and being married (P < .001) were both protective against conversion.

CONCLUSION

Certain intrinsic patient factors may predispose a patient to an IP stay, and an understanding of predisposing factors which could lead to IP conversion may improve perioperative planning moving forward.

Trends in Outpatient Total Knee Arthroplasty (TKA) from 2012 to 2020

BACKGROUND

Trends over the past decade suggest a steady increase in the proportion of total knee arthroplasty (TKA) performed on an outpatient basis. However, the optimal patient selection criteria for outpatient TKA remain unclear. We aimed to describe longitudinal trends in patients selected for outpatient TKA and identify risk factors for 30-day morbidity following inpatient and outpatient TKA.

METHODS

We identified 379,959 primary TKA patients, 17,170 (4.5%) of whom underwent outpatient surgery from 2012 to 2020 within a large national database. We used regression models to evaluate trends in outpatient TKA, factors associated with undergoing outpatient (vs. inpatient) TKA and 30-day morbidity following outpatient and inpatient TKA. We used Receiver Operating Curves (ROC) to examine cut-off points for continuous risk factors.

RESULTS

The proportion of patients undergoing outpatient TKA increased from 0.4% in 2012 to 14.1% in 2020. Younger age, male sex, lower body mass index (BMI), higher hematocrit, and fewer comorbidities were associated with receiving outpatient (vs. inpatient) TKA. Variables associated with 30-day morbidity in the outpatient group included older age, chronic dyspnea, chronic obstructive pulmonary disease (COPD), and higher BMI. ROC curves indicated outpatients aged 68 and older, or with a BMI of 31.4 or higher were more likely to experience 30-day complications.

CONCLUSION

The proportion of patients undergoing outpatient TKA has been increasing since 2012. Older age (≥68 years), a higher BMI (≥31.4), and comorbidities such as chronic dyspnea, COPD, diabetes, and hypertension were associated with an increased odds of 30-day morbidity following outpatient TKA.

Analysis of revision rates and complication rates among patients undergoing unicompartmental and bicompartmental knee Arthroplasties when compared to Total knee arthroplasty

BACKGROUND

With recent advances in partial knee arthroplasty, there is conflicting data regarding the outcomes and revision rates for bicompartmental knee arthroplasty (BKA) and unicompartamental knee arthroplasty (UKA) compared to total knee arthroplasty (TKA). This study uses national data to compare surgical and medical complications of UKA, BKA, and TKA to aid surgical decision-making.

METHODS

A retrospective cohort analysis was done using the Mariner dataset of the PearlDiver patient records database from 2010-2019. Current Procedural Terminology (CPT) codes were used to identify patients who underwent UKA, BKA, and TKA for a primary indication of osteoarthritis (OA). Univariate and multivariable analyses were performed to determine 1-year and 2-year revision, prosthetic joint infection (PJI), and loosening, 1-year manipulation under anesthesia (MUA), and 90-day postoperative medical complications.

RESULTS

The BKA cohort was found to have higher odds of one and two-year revision compared to UKA and TKA cohorts. Additionally, the UKA cohort had higher odds of one and two-year revision but lower odds of 1-year MUA than the TKA cohort. However, both the BKA and UKA cohorts had lower odds of any 90-day postoperative complications when compared to the TKA cohort.

CONCLUSIONS

Even with modern implants and approaches, our study found that revision rates are highest for BKA followed by UKA and TKA at two years postoperatively. Notably, medical complications were much less common after all partial knee replacement types when compared to TKA. These findings may be used to guide patients in selecting the appropriate surgery to meet their goals and expectations.

Accelerated discharge after aseptic revision knee arthroplasty is not associated with early readmission and reoperation

Aims

In the last decade, perioperative advancements have expanded the use of outpatient primary total knee arthroplasty (TKA). Despite this, there remains limited data on expedited discharge after revision TKA. This study compared 30-day readmissions and reoperations in patients undergoing revision TKA with a hospital stay greater or less than 24 hours. The authors hypothesized that expedited discharge in select patients would not be associated with increased 30-day readmissions and reoperations.

Methods

Aseptic revision TKAs in the National Surgical Quality Improvement Program database were reviewed from 2013 to 2020. TKAs were stratified by length of hospital stay (greater or less than 24 hours). Patient demographic details, medical comorbidities, American Society of Anesthesiologists (ASA) grade, operating time, components revised, 30-day readmissions, and reoperations were compared. Multivariate analysis evaluated predictors of discharge prior to 24 hours, 30-day readmission, and reoperation.

Results

Of 21,610 aseptic revision TKAs evaluated, 530 were discharged within 24 hours. Short-stay patients were younger (63.1 years (49 to 78) vs 65.1 years (18 to 94)), with lower BMI (32.3 kg/m2 (17 to 47) vs 33.6 kg/m2 (19 to 54) and lower ASA grades. Diabetes, chronic obstructive pulmonary disease, hypertension, and cancer were all associated with a hospital stay over 24 hours. Single component revisions (56.8% (n = 301) vs 32.4% (n = 6,823)), and shorter mean operating time (89.7 minutes (25 to 275) vs 130.2 minutes (30 to 517)) were associated with accelerated discharge. Accelerated discharge was not associated with 30-day readmission and reoperation.

Conclusion

Accelerated discharge after revision TKA did not increase short-term complications, readmissions, or reoperations. Further efforts to decrease hospital stays in this setting should be evaluated. Cite this article: Bone Joint J 2022;104-B(12):1323–1328.

Significant Reduction in Short-Term Complications Following Unicompartmental Versus Total Knee Arthroplasty: A Propensity Score Matched Analysis

BACKGROUND

Total knee arthroplasty (TKA) is a gold standard surgical treatment for end-stage arthritis and unicompartmental knee arthroplasty (UKA) is an alternative for localized disease in appropriate patients. Both have been shown to have equivalent complications in the short-term period. We aimed to explore the differences in 30-day complication rates between UKA and TKA using recent data.

METHODS

Current Procedural Terminology codes identified patients in the American College of Surgeons National Surgical Quality Improvement Program database who underwent primary TKA or UKA from 2014 to 2018. Propensity score matching addressed demographic differences. Rate of any adverse event (AAE) and complications were compared.

RESULTS

We identified 279,852 patients with 270,786 and 9,066 undergoing TKA and UKA. No significant difference was observed in baseline demographics after matching. The AAE rate differed significantly between TKA (5.07%) and UKA (2.38%) cohorts (P < .001). TKA group experienced more wound dehiscence, cerebrovascular accident, postoperative blood transfusion, deep vein thrombosis, and requirement for postoperative intubation. Rate of extended length of stay differed between the TKA (11.35%) and UKA (4.89%) cohorts (P < .001). Accounting for all other variables, preoperative corticosteroid use, bleeding disorder, and chronic obstructive pulmonary disease increased the risk for AAE for both groups. Increasing American Society of Anesthesiologists class also increased the odds for complication proportionally with increasing age and operative time.

CONCLUSION

Contrary to previous data, we found a significantly higher 30-day complication rate in TKA patients. TKA patients had a higher likelihood of having an extended length of stay. Multivariable analysis identified preoperative steroid use, bleeding disorder, and chronic obstructive pulmonary disease as risk factors for developing adverse events for both groups.

LEVEL OF EVIDENCE

Level III.

A Morphometric Fixed-Bearing Unicompartmental Knee Arthroplasty Can Reproduce Normal Knee Kinematics. An In Vitro Robotic Evaluation

Background

Methods

Results

Conclusion

Amount of CMS Reduction in Facility Reimbursement Following Removal of Total Hip Arthroplasty From the Inpatient-Only List Far Exceeds Reduction in Actual Care Cost

BACKGROUND

Starting in 2020, Centers for Medicare and Medicaid Services (CMS) removed total hip arthroplasty (THA) from the inpatient-only list, resulting in an average of $1637 per case reduction in facility reimbursement. The purpose of this study is to determine whether the reduction in reimbursement is justified by comparing the difference in true facility costs between inpatient and outpatient THA.

METHODS

We identified a consecutive series of 5271 primary THA procedures from 2015 to 2019. Itemized procedural costs were calculated using a time-driven activity-based costing algorithm. Outpatient procedures were defined as those with less than a 24-hour length of stay. We compared patient demographics, comorbidities, and itemized costs between inpatient and outpatient procedures. A multivariate analysis was performed to determine the independent effect of outpatient status on true facility costs.

RESULTS

There were 783 (14.9%) outpatient THA procedures. The outpatient THA procedures incurred lower mean personnel ($1428 vs $2226, P < .001), supply ($4713 vs $4739, P < .001), and overall facility costs ($6141 vs $6595, P < .001) when compared with the same THA procedures done inpatient. When controlling for confounding variables, outpatient status was associated with a reduction in total facility costs of $825 (95% confidence interval, $734-$916, P < .001).

CONCLUSION

The reduction in CMS reimbursement far exceeds the $825 per-patient cost savings that can be achieved by a facility by performing THA as an outpatient. CMS should reconsider the Outpatient Prospective Payment System classification of THA to better incentivize surgeons to perform THA as a lower-cost outpatient procedure when safe and appropriate.

Despite Equivalent Medicare Reimbursement, Facility Costs for Outpatient Total Knee Arthroplasty Are Higher Than Unicompartmental Knee Arthroplasty

BACKGROUND

With the recent removal of total knee arthroplasty (TKA) from the Centers for Medicare and Medicaid Services (CMS) Inpatient Only list, facility reimbursement for outpatient TKA now falls under the Outpatient Prospective Payment System at the same rate as unicompartmental knee arthroplasty (UKA). The purpose of this study was to compare true facility costs of patients undergoing outpatient TKA with those undergoing UKA.

METHODS

We reviewed a consecutive series of 2310 outpatient TKA and 231 UKA patients from 2018 to 2019. Outpatient status was defined as a hospital stay of less than 2 midnights. Facility costs were calculated using a time-driven, activity-based costing algorithm. Implants, supplies, medications, and personnel costs were compared between outpatient TKA and UKA patients. A multivariate analysis was performed to control for confounding medical and demographic variables.

RESULTS

When compared with patients undergoing UKA, outpatient TKA patients had higher implant costs ($3403 vs $3081; P < .001) and overall hospital costs ($6350 vs $5594; P < .001). Outpatient TKA patients had a greater length of stay (1.2 vs 0.5 days; P < .001) and greater postoperative personnel costs ($783 vs $166; P < .001) than UKA patients. When controlling for comorbidities, outpatient TKA was associated with a $803 (P < .001) increase in overall facility costs compared with UKA.

CONCLUSION

Despite equivalent reimbursement from CMS as UKA, outpatient TKA has increased facility costs to the hospital. Although implant costs can vary greatly by institution, CMS should consider appropriately reimbursing outpatient TKA for the additional personnel costs when compared with UKA.

Length of Stay and 90-Day Readmission/Complication Rates in Unicompartmental Versus Total Knee Arthroplasty: A Propensity-Score-Matched Study of 10,494 Procedures Performed in a Fast-Track Setup

BACKGROUND

Whether to use unicompartmental knee arthroplasty (UKA) or total knee arthroplasty (TKA) for appropriate osteoarthritis cases is a subject of debate. UKA potentially offers faster recovery and fewer short-term complications. However, reported differences in preoperative comorbidity between TKA and UKA-treated patients could affect outcomes. The aim of this study was to investigate differences in the length of the postoperative hospital stay (LOS) as well as readmissions and complications within 90 days after surgery between matched UKA and TKA cohorts.

METHODS

Patients undergoing UKA or TKA in a fast-track setup at 9 orthopaedic centers from 2010 to 2017 were included in the study. Propensity score matching with exact matching for surgical year was used to address differences in demographics and comorbidity between the UKA and TKA groups, resulting in a matched cohort of 2,786 patients who underwent UKA and 7,708 who underwent TKA. Univariable linear or logistic regression models, multivariable mixed-effects models, and a chi-square test were used to investigate differences in LOS, readmissions, and complications between the UKA and TKA groups.

RESULTS

The UKA group had a shorter median LOS than the TKA group (1 compared with 2 days, p < 0.001). The UKA group was more likely to be discharged on the day of surgery (21.1% compared with 0.5%, odds ratio [OR] = 38.5, 95% confidence interval [CI] = 27.0 to 52.6) and less likely to have an LOS of >2 days (OR = 0.20, 95% CI = 0.17 to 0.24) compared with the TKA group. There was no difference in the 90-day readmission rate (p = 0.611) between the groups. The UKA group had fewer periprosthetic joint infections (OR = 0.50, 95% CI = 0.26 to 0.99) and reoperations (OR = 0.40, 95% CI = 0.20 to 0.81) compared with the TKA group. However, aseptic revisions were more frequent in the UKA group (OR = 2.5, 95% CI = 1.1 to 6.0).

CONCLUSIONS

The UKA group had shorter hospital stays, a higher rate of discharge on the day of surgery, and fewer periprosthetic joint infections and reoperations compared with the matched TKA group. However, the TKA group had fewer aseptic revisions. Our findings support the use of UKA in a fast-track setup when indicated.

LEVEL OF EVIDENCE

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

Social determinants of health in total knee arthroplasty : are social factors associated with increased 30-day post-discharge cost of care and length of stay?

AIMS

Social determinants of health (SDOHs) may contribute to the total cost of care (TCOC) for patients undergoing total knee arthroplasty (TKA). The aim of this study was to investigate the association between demographic data, health status, and SDOHs on 30-day length of stay (LOS) and TCOC after this procedure.

METHODS

Patients who underwent TKA between 1 January 2018 and 31 December 2019 were identified. A total of 234 patients with complete SDOH data were included. Data were drawn from the Chesapeake Regional Information System, the Centers for Disease Control social vulnerability index (SVI), the US Department of Agriculture, and institutional electronic medical records. The SVI identifies areas vulnerable to catastrophic events with four themed scores: socioeconomic status; household composition and disability; minority status and language; and housing and transportation. Food deserts were defined as neighbourhoods located one or ten miles from a grocery store in urban and rural areas, respectively. Multiple regression analyses were performed to determine associations with LOS and costs after controlling for various demographic parameters.

RESULTS

Divorced status was significantly associated with an increased LOS (p = 0.043). Comorbidities significantly associated with an increased LOS included chronic obstructive pulmonary disease/asthma and congestive heart failure (p = 0.043 and p = 0.001, respectively). Communities with a higher density of tobacco stores were significantly associated with an increased LOS (p = 0.017). Comorbidities significantly associated with an increased TCOC included chronic obstructive pulmonary disease (p = 0.004), dementia (p = 0.048), and heart failure (p = 0.007). Increased TCOCs were significantly associated with patients who lived in food deserts (p = 0.001) and in areas with an increased density of tobacco stores (p = 0.023).

CONCLUSION

Divorced marital status was significantly associated with an increased LOS following TKA. Living in food deserts and in communities with more tobacco stores were significant risk factors for increased LOS and TCOC. Food access and ease of acquiring tobacco may both prove to be prognostic of outcome after TKA and an opportunity for intervention. Cite this article: Bone Joint J 2021;103-B(6 Supple A):113-118.

Impact of Intrathecal Fentanyl on Hospital Outcomes for Patients Undergoing Primary Total Hip Arthroplasty With Neuraxial Anesthesia

BACKGROUND

Intrathecal opioids have been used to reduce pain after total joint arthroplasty; however, the utility of these drugs is disputed. We examined the impact of eliminating intrathecal fentanyl on outcomes for patients undergoing direct anterior approach total hip arthroplasty (THA).

METHODS

Retrospective review of 376 THA patients from a single institution was conducted. Univariate analysis was used to compare intraoperative medication usage and postoperative outcomes for THA patients receiving intrathecal fentanyl compared with those who did not receive intrathecal fentanyl.

RESULTS

Recovery room pain scores were significantly lower for patients who received intrathecal fentanyl (intrathecal fentanyl 1.4 vs no 2.2, P = .001), but no difference in opioid consumption was observed (intrathecal fentanyl 9.3 milligram morphine equivalent vs no 10.5 milligram morphine equivalent, P = .200). Intraoperative use and dose of intravenous morphine, hydromorphone, and dexamethasone did not differ significantly between groups. There were no significant differences in length of stay between the groups (intrathecal fentanyl 1.1 days vs 1.1 days, P = .973), 90-day readmission, or recatherization rates between groups (readmission, intrathecal fentanyl 4.8% vs no 5.8%, P = .709; recatherization, intrathecal fentanyl 0% vs no 0.7%, P = 1.00).

CONCLUSION

The administration of intrathecal fentanyl does not have a significant effect on early postoperative narcotic consumption, length of stay, 90-day readmissions, or recatheterization after THA with neuraxial anesthesia. Intrathecal fentanyl does not appear to improve outcomes and should not be included as a standard element of THA rapid recovery protocols.

General vs Neuraxial Anesthesia in Direct Anterior Approach Total Hip Arthroplasty: Effect on Length of Stay and Early Pain Control

BACKGROUND

Recent literature has suggested some benefits for neuraxial anesthesia (NA) as an alternative for general anesthesia (GA) for primary total hip arthroplasty patients. We examined the impact of NA vs GA on outcomes for patients undergoing direct anterior (DA) approach total hip arthroplasty (THA) in an institution with established rapid recovery protocols.

METHODS

A retrospective review was conducted for 500 consecutive THA patients from a single institution. Univariate analysis and multivariate linear regression were used to compare outcomes for THA patients receiving NA and GA.

RESULTS

There was a significant difference in length of stay with NA patients having a shorter length of stay (NA 32.7 hours vs GA 38.1 hours, P = .003). Patients receiving NA had significantly lower PACU morphine milligram equivalents (MME) (NA 10.2 MME vs GA 15.6 MME, P < .001) and reported a lower score on the PACU pain numeric rating scale (NA 2.1 vs GA 3.7, P < .001).

CONCLUSION

Neuraxial anesthesia is associated with decreased LOS, decreased PACU MME, and a lower PACU pain score for patients undergoing primary DA THA. These trends remained consistent when controlling for age, gender, BMI, and ASA.

Is the New Outpatient Prospective Payment System Classification for Outpatient Total Knee Arthroplasty Appropriate?

BACKGROUND

In 2018, the Centers for Medicare and Medicaid Services removed total knee arthroplasty (TKA) from the inpatient-only list, resulting in payment through the Outpatient Prospective Payment System with an average $3157 reduction. The purpose of this study is to determine if the reimbursement is justified by comparing the difference in facility costs between inpatient and outpatient TKAs.

METHODS

We identified 4496 consecutive primary TKA procedures performed at 2 hospitals from 2015 to 2019. Itemized facility costs were calculated using a time-driven activity-based costing algorithm. Outpatient procedures were defined as those with a length of stay of less than 2 midnights (3851, 86%). Patient demographics, comorbidities, and itemized costs were compared between groups. A multivariate regression analysis was performed to determine the independent effect of outpatient status on true facility costs.

RESULTS

Outpatient TKA patients had lower mean postoperative personnel costs ($1809 vs $947, P < .001), supply costs ($4347 vs $4229, P < .001), and overall total facility costs ($7371 vs $6937, P < .001) than inpatient TKA patients. Controlling for a younger patient cohort with fewer medical comorbidities, outpatient status was associated with a reduction in total facility costs of $972 (95% confidence interval $883-$1060, P < .001) compared to inpatient TKA.

CONCLUSION

Outpatient TKA costs hospitals nearly $1000 per patient less than inpatient TKA, yet the average difference in Medicare reimbursement for an outpatient procedure is $3157 less per patient. Centers for Medicare and Medicaid Services should reconsider the Outpatient Prospective Payment System classification of TKA to better incentivize surgeons to perform TKA as a lower cost outpatient procedure when safe and appropriate.

Assessing Preoperative Pain Sensitivity Predicts the Postoperative Analgesic Requirement and Recovery after Total Knee Arthroplasty: A Prospective Study of 178 Patients

BACKGROUND

The aim of this article is to study the correlation between preoperative pain sensitivity and postoperative pain and analgesic requirements for patients undergoing primary total knee arthroplasty.

METHODS

Between December 2018 and April 2019, the pain sensitivity of 178 consecutive patients undergoing primary total knee arthroplasty was assessed preoperatively with a digital algometer. The patients reported the VAS (visual analog scale) score at 3 instances of needle prick (phlebotomy, glucometer blood sugar, intradermal antibiotic test dose), during the range of movements and completed the Depression Anxiety Stress Scale score. Postoperative VAS score, analgesic requirement, and physiotherapy milestones were recorded in all these patients on day 0 to day 4.

RESULTS

The average age of the patients was 64.13 years and 69.1% were females. Females had lower mean algometry values (56.12 ± 12.77 [standard deviation]) compared to males (71.09 ± 18.78 [standard deviation]) (P < .001). Higher Depression Anxiety Stress Scale correlated with lower algometry values (P < .001). The postoperative VAS score was 2.54 ± 0.59 on the day of surgery which increased to 3.27 ± 0.69 on day 1 after mobilization (P < .001) and reduced to 1.67 ± 0.62 on day 4. Low algometer score correlated with higher postoperative VAS score (P < .05), increased analgesic requirement, and opioid utilization (P < .001), delay in achieving an optimum range of movements (P < .001) and independent ambulation (P < .001).

CONCLUSION

Preoperative assessment of pain sensitivity predicts postoperative analgesic requirements and recovery. Patients with a lower pain threshold should be counseled preoperatively and also receive a better titration of analgesics perioperatively and prolonged physiotherapy.

Excellent outcomes for lateral unicompartmental knee arthroplasty: Multicenter 268-case series at 5 to 23 years' follow-up

INTRODUCTION

Isolated lateral compartment osteoarthritis of the knee (LCOA) is 10 times less frequent than medial compartment involvement. Long-term assessments of unicompartmental knee arthroplasty (UKA) in this indication are rare, with small series.

HYPOTHESIS

Survival and functional outcome of lateral UKA in a large series are quite acceptable; the strategy is suited for isolated LCOA.

MATERIAL AND METHOD

A multicenter retrospective study in 6 French health establishments included all lateral UKAs performed between January 1988 and September 2014. Clinical data (range of motion, International Knee Society (IKS) knee and function scores, satisfaction), paraclinical data (radiologic angles) and complications were prospectively entered in medical files during follow-up and analyzed retrospectively at end of follow-up.

RESULTS

During the study period, 311 lateral UKAs were performed in 295 patients, using 5 fixed-bearing implant models. Twenty-eight patients died within 5 years, and 15 (4.8%) were lost to follow-up. The series thus comprised 268 lateral UKAs in 63 male and 205 female patients, with a mean age of 68.8±10.5 years, including 7 cases of post-traumatic osteoarthritis and 4 of aseptic osteonecrosis. Mean follow-up was 9.1 years (range, 5-23 years), implant survivorship with failure defined as all-cause revision surgery was 85.4% at 10 years and 79.4% at 20 years. At last follow-up, IKS knee score was 87.0 and IKS function score 80.2. Maximal flexion was 125°. 94.3% of patients were satisfied or very satisfied. The main cause of revision surgery was osteoarthritis in another knee compartment (66,7%, n=26).

CONCLUSION

Lateral UKA showed good survivorship, comparable to medial UKA, with good functional results and excellent long-term satisfaction.

LEVEL OF EVIDENCE

IV, retrospective cohort study.

2020 John N. Insall Award: Removal of total knee arthroplasty from the inpatient-only list adversely affects bundled payment programmes

Aims

The purpose of this study was to determine the impact of the removal of total knee arthroplasty (TKA) from the Medicare Inpatient Only (IPO) list on our Bundled Payments for Care Improvement (BPCI) Initiative in 2018.

Methods

We examined our institutional database to identify all Medicare patients who underwent primary TKA from 2017 to 2018. Hospital inpatient or outpatient status was cross-referenced with Centers for Medicare & Medicaid Services (CMS) claims data. Demographics, comorbidities, and outcomes were compared between patients classified as ‘outpatient’ and ‘inpatient’ TKA. Episode-of-care BPCI costs were then compared from 2017 to 2018.

Results

Of the 2,135 primary TKA patients in 2018, 908 (43%) were classified as an outpatient and were excluded from BPCI. Inpatient classified patients had longer mean length of stay (1.9 (SD 1.4) vs 1.4 (SD 1.7) days, p < 0.001) and higher rates of discharge to rehabilitation (17% vs 3%, p < 0.001). Post-acute care costs increased when comparing the BPCI patients from 2017 to 2018, ($5,037 (SD $7,792) vs $5793 (SD $8,311), p = 0.010). The removal of TKA from the IPO list turned a net savings of $53,805 in 2017 into a loss of $219,747 in 2018 for our BPCI programme.

Conclusions

Following the removal of TKA from the IPO list, nearly half of the patients at our institution were inappropriately classified as an outpatient. Our target price was increased and our institution realized a substantial loss in 2018 BPCI despite strong quality metrics. CMS should address its negative implications on bundled payment programmes. Cite this article: Bone Joint J 2020;102-B(6 Supple A):19–23.

The Effect of Neuraxial Anesthesia on Postoperative Outcomes in Total Joint Arthroplasty With Rapid Recovery Protocols

BACKGROUND

Compared to general anesthesia (GA), neuraxial anesthesia (NA) has been associated with improved outcomes after total joint arthroplasty (TJA). We examined the impact of NA on patient outcomes in an institution with an established rapid recovery protocol.

METHODS

This is a single-institution retrospective analysis of 5914 consecutive primary TJA performed from July 2015 to June 2018. Univariate tests and multivariate regression compared length of stay (LOS), transfusion rates, hematocrit levels, discharge disposition, and emergency room returns between patients receiving GA and NA.

RESULTS

Patients receiving NA had a significantly shorter LOS (total hip arthroplasty [THA]: GA 1.74 vs NA 1.36 days, P < .001; total knee arthroplasty [TKA]: GA 1.77 vs NA 1.64 days, P < .001). Both THA and TKA patients receiving NA were less likely to require transfusion (THA: GA 5.8% vs NA 1.6%, P < .001; TKA: GA 2.5% vs NA 0.5%, P < .001) and had a higher postoperative hematocrit (THA: GA 32.50% vs NA 33.22%, P < .001; TKA GA 33.57 vs NA 34.50%, P < .001). Patients receiving NA were more likely to discharge home (THA: GA 83.4% vs NA 92.3%, P < .001; TKA: GA 83.3% vs NA 86.3%, P = .010) (THA: NA adjusted OR [aOR] 2.04, P < .001; TKA: NA aOR 1.23, P = .048) and had significantly lower rates of 90-day emergency room visits (THA: NA aOR 0.61, P = .005; TKA: NA aOR 0.74, P = .034).

CONCLUSION

NA appears to contribute to decreased LOS, short-term complications, and transfusions while facilitating home discharge following TKA and THA. These trends are consistent when controlling for patient-specific risk factors, suggesting NA may enhance outcomes for patients with increased age, body mass index, and comorbidities.

LEVEL OF EVIDENCE

Level III Retrospective Cohort Study.

Financial impact of removal of total knee arthroplasty from the inpatient-only list for a physician-owned BPCI program

Objective

Assessing financial effects of removal of TKA from CMS inpatient-only list on physician-owned bundles.

Methods

We determined whether Medicare TKAs remained inpatient, versus changed to observational. We used CMS data to determine savings. Direct costs associated with BPCI were calculated.

Results

7/28 TKAs (25.0%) had inpatient status changed to observational, excluding them from BPCI. Estimated savings losses were $24,332. Direct costs for administrating BPCI were $51,250. Had the rate of patients changed to observational been 50%, bundle savings from remaining patients would be less than direct costs.

Conclusion

Removing TKA from CMS inpatient-only list may have negative financial implications.

Medicare coverage is an independent predictor of prolonged hospitalization after primary total joint arthroplasty

The purpose of this study was to investigate the association between insurance type and length of stay (LOS) in primary total joint arthroplasty. A retrospective review of 848 patients was performed. Patients were divided into 3 groups based on their insurance type: Medicare, Medicaid, or commercial coverage. Medicare patients had a significantly higher rate of LOS > 2 days than the Medicaid and commercial groups (P < .0001). The effect of Medicare coverage on LOS remained significant even after controlling for baseline differences among the study groups. There were no differences in the rates of 90-day emergency room visits and readmissions between the 3 groups (P > .05). Arthroplasty surgeons not experienced with outpatient surgery should not be pressured to default to outpatient admission in Medicare patients.

Unintended Bundled Payments for Care Improvement Consequences After Removal of Total Knee Arthroplasty From Inpatient-Only List

BACKGROUND

The Centers for Medicare and Medicaid Services beginning in 2013 introduced the Bundled Payments for Care Improvement (BPCI) initiative to test innovative payment and service delivery models. Early implementers of the BPCI program have shown decreased hospital length of stays, discharges to inpatient facilities, and readmission rates with overall cost savings. Removal of total knee arthroplasty from the Medicare inpatient-only list may potentially cause substantial changes in patients included in BPCI bundles in 2018.

METHODS

The 2017 Centers for Medicare and Medicaid Services data were used to compare total expenditures of diagnosis-related groups 469 and 470. Medicare patients who underwent total knee arthroplasty between January 2017 and December 2017 were defined as group one (n = 1024) and expenditures were compared to group two patients (n = 631) that included only those patients staying greater than 24 hours. Postacute events within the 90-day episode including admission to an inpatient rehabilitation facility/skilled nursing facility (SNF), home health (HH), and readmissions were analyzed. Expenditures were converted to 2018 dollars using Consumer Price Index. Statistical analysis of expenditures was performed with Wilcoxon Tests.

RESULTS

Median expenditures were $15,587 (interquartile range [IQR] $13,915-$17,684) for group 1 and $16,706 (IQR $15,333-$19,247) for group 2 (P < .001). Median postacute care spend was $3817 (IQR $2431-$5057) for group 1 and $4195 (IQR $3049-$6064) for group 2 patients (P < .001). Compared with group 1 patients, group 2 patients had a higher rate of SNF admissions (21% vs 13%), inpatient rehabilitation facility admissions (0.16% vs 0.1%), HH (72% vs 69%), and readmissions (5% vs 4%).

CONCLUSION

Implications of the removal of total knee arthroplasty from the inpatient-only list could potentially remove up to 40% of patients from the BPCI program leading to substantially less savings on average $1100 per patient. Remaining bundle patients are also more likely to require HH and SNF after discharge.

Predicting Inpatient Status After Primary Total Knee Arthroplasty in Medicare-Aged Patients

BACKGROUND

The Centers for Medicare and Medicaid Services (CMS) removed total knee arthroplasty (TKA) from its inpatient only (IPO) list as of January 1, 2018. The purpose of this study was to establish a risk-stratifying nomogram to aid in determining the need for inpatient admission among Medicare-aged patients undergoing primary TKA.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program database was queried to identify all patients aged ≥65 years who underwent primary TKA between 2006 and 2015. The primary outcome measure was inpatient admission, as defined by hospital length of stay longer than 2 days. Multiple demographic, comorbid, and perioperative variables were incorporated in a multivariate logistic regression model to yield a risk stratification nomogram.

RESULTS

Sixty-one thousand two hundred eighty-four inpatient and 26,066 outpatient admissions were analyzed. Age >80 years (odds ratio [OR] = 2.27, P < .0001, 95% confidence interval [CI] = 2.13-2.42), simultaneous bilateral TKA (OR = 2.02, P < .0001, 95% CI = 1.77-2.30), dependent functional status (OR = 1.95, P < .0001, 95% CI = 1.62-2.35), metastatic cancer (OR = 1.91, P = .055, 95% CI = 0.99-3.73), and female gender (OR = 1.76, P < .0001, 95% CI = 1.70-1.82) were the greatest determinants of inpatient stay. The resulting predictive model demonstrated acceptable discrimination and excellent calibration.

CONCLUSION

Our model enabled a reliable and straightforward identification of the most suitable candidates for inpatient admission in Medicare aged-patients undergoing primary TKA. Larger multicenter studies are necessary to externally validate the proposed predictive nomogram.

High Survival Rate and Very Low Wear of Lateral Unicompartmental Arthroplasty at Long Term: A Case Series of 54 Cases at a Mean Follow-Up of 17 Years

BACKGROUND

Survivorship of lateral unicompartmental knee arthroplasty (UKA) has progressively improved. However, there are few studies describing long-term results, and no study reports on polyethylene (PE) wear in lateral unicompartmental arthroplasty. The aims of this study are to determine the survival rate of lateral UKA with a fixed, all-PE bearing, and the PE wear of the tibial implant at a minimum of 15 years follow-up.

METHODS

From January 1988 to October 2003, we performed 54 lateral UKAs in 52 patients. All patients had isolated lateral osteoarthritis (OA). The mean age at the index procedure was 65.4 ± 11 years. Thirty-nine UKAs were available for follow-up (30 alive and 9 dead after 15 years). Twelve patients had died before 15 years and 3 patients were lost to follow-up. The mean follow-up was 17.9 years (range, 15-23 years).

RESULTS

At the final follow-up, 8 knees of 39 (20.5%) had a surgical revision. The cumulative survival rate was 82.1% at 15 years and 79.4% at 20 years. The main reason of revision was progression of OA (87.5%), followed by aseptic loosening of the tibial component (12.5%). With a mean follow-up of 17.9 years, the mean PE wear was 0.061 mm/y. There was no radiographic loosening in the surviving implants and no revisions for wear. The mean functional International Knee Society score was 66.5 ± 26.8, with a mean objective score of 84.4 points ± 13.2. In the population without revision, 90.5% were satisfied or very satisfied at the latest follow-up.

CONCLUSION

Lateral UKA with a fixed, all-PE tibial bearing and a femoral resurfacing implant presents a high survivorship at long term, with very low PE wear.

Patient Perceptions of the Safety of Outpatient Total Knee Arthroplasty

BACKGROUND

Outpatient total joint arthroplasty is considered safe in a selected group of patients, based primarily on complications. However, patient perception of the safety of outpatient total joint arthroplasty is unknown. This study assesses patient perceptions of the potential benefits of and barriers to outpatient total knee arthroplasty among a cohort of patients who have recently undergone the procedure.

METHODS

Patients who underwent unilateral primary total knee arthroplasty between March 1, 2017, and September 30, 2017 at our institution were given a questionnaire, in which they were asked about prior knowledge regarding outpatient total knee arthroplasty, their perceived ability to undergo the procedure as an outpatient, and their perceived risks and benefits to outpatient surgery.

RESULTS

Three hundred forty-six patients completed the survey. Over 70% of patients did not think that they would be able to undergo total knee arthroplasty as an outpatient. Their primary concerns were pain, being able to go to the bathroom, and falls.

CONCLUSIONS

Patients in this study largely would not feel safe undergoing total knee arthroplasty on an outpatient basis. Payers should not only take into account existing literature but also the concerns and perceived needs of patients, before encouraging widespread implementation of outpatient total knee arthroplasty.

Patient relevant outcomes of unicompartmental versus total knee replacement: systematic review and meta-analysis

OBJECTIVE

To present a clear and comprehensive summary of the published data on unicompartmental knee replacement (UKA) or total knee replacement (TKA), comparing domains of outcome that have been shown to be important to patients and clinicians to allow informed decision making.

DESIGN

Systematic review using data from randomised controlled trials, nationwide databases or joint registries, and large cohort studies.

DATA SOURCES

Medline, Embase, Cochrane Controlled Register of Trials (CENTRAL), and Clinical Trials.gov, searched between 1 January 1997 and 31 December 2018.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Studies published in the past 20 years, comparing outcomes of primary UKA with TKA in adult patients. Studies were excluded if they involved fewer than 50 participants, or if translation into English was not available.

RESULTS

60 eligible studies were separated into three methodological groups: seven publications from six randomised controlled trials, 17 national joint registries and national database studies, and 36 cohort studies. Results for each domain of outcome varied depending on the level of data, and findings were not always significant. Analysis of the three groups of studies showed significantly shorter hospital stays after UKA than after TKA (-1.20 days (95% confidence interval -1.67 to -0.73), -1.43 (-1.53 to -1.33), and -1.73 (-2.30 to -1.16), respectively). There was no significant difference in pain, based on patient reported outcome measures (PROMs), but significantly better functional PROM scores for UKA than for TKA in both non-trial groups (mean difference -0.58 (-0.88 to -0.27) and -0.32 (-0.48 to -0.15), respectively). Regarding major complications, trials and cohort studies had non-significant results, but mortality after TKA was significantly higher in registry and large database studies (risk ratio 0.27 (0.16 to 0.45)), as were venous thromboembolic events (0.39 (0.27 to 0.57)) and major cardiac events (0.22 (0.06 to 0.86)). Early reoperation for any reason was higher after TKA than after UKA, but revision rates at five years remained higher for UKA in all three study groups (risk ratio 5.95 (1.29 to 27.59), 2.50 (1.77 to 3.54), and 3.13 (1.89 to 5.17), respectively).

CONCLUSIONS

TKA and UKA are both viable options for the treatment of isolated unicompartmental osteoarthritis. By directly comparing the two treatments, this study demonstrates better results for UKA in several outcome domains. However, the risk of revision surgery was lower for TKA. This information should be available to patients as part of the shared decision making process in choosing treatment options.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO number CRD42018089972.

Predicting Inpatient Status After Total Hip Arthroplasty in Medicare-Aged Patients

BACKGROUND

The Centers for Medicare and Medicaid Services has solicited comments regarding the removal of total hip arthroplasty (THA) from its inpatient-only list. The goal of this study is to develop and internally validate a risk stratification nomogram to aid in the identification of optimal inpatient candidates in this patient population.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program database was utilized to identify all patients >65 years of age who underwent primary THA between 2006 and 2015. Inpatient stay was the primary outcome measure, as defined by stay >2 days in length. The impact of numerous demographic, comorbid, and perioperative variables was assessed through a multivariable logistic regression analysis to construct a predictive nomogram.

RESULTS

In total, 30,587 inpatient THAs and 17,024 outpatient THAs were analyzed. Heart failure (odds ratio [OR] 2.11, P = .001), simultaneous bilateral THA (OR 2.47, P < .0001), age >80 years (OR 2.91, P < .0001), female gender (OR 1.90, P < .0001), and dependent functional status (OR 1.89, P < .0001) were the most influential determinants of inpatient status. The final prediction algorithm showed good accuracy, excellent calibration, and internal validation (bias-corrected concordance index of 0.69).

CONCLUSION

Our model enabled accurate and simple identification of the best candidates for inpatient admission after THA in Medicare-aged patients. Given the increasing feasibility of outpatient THA coupled with the likelihood of THA being removed from the Centers for Medicare and Medicaid Services inpatient-only list, this model provides a framework to guide discussion and decision-making for stakeholders.

The Unintended Impact of the Removal of Total Knee Arthroplasty From the Center for Medicare and Medicaid Services Inpatient-Only List

BACKGROUND

Total knee arthroplasty (TKA) was removed from the Centers for Medicare and Medicaid Services (CMS) Inpatient-Only (IPO) list starting January 1, 2018. Many hospitals responded by instructing surgeons to schedule all TKAs as outpatient procedures, and some local Medicare Advantage contractors began to expect outpatient status for all or most TKA cases. This activity and ensuing confusion has caused considerable unintended disruption for surgeons, hospitals, and patients. The purpose of this study was to gauge the impact on providers and patients.

METHODS

Active members of the American Association of Hip and Knee Surgeons were sent a 9-question survey asking if the surgeon's hospital was treating all patients undergoing TKA as outpatients and if Medicare Advantage administrators and commercial payers were treating all or most the same. Questions also inquired about the impact on surgeon practices and their patients.

RESULTS

Seven hundred thirty members (26%) responded; of which, 59.5% reported that their hospitals have instructed them that all Medicare TKAs should be scheduled as outpatient procedures; 40.5% have been asked to use proscribed documentation to justify that change; 30.4% reported that their patients have incurred added personal cost secondary to their surgical procedure being billed as an outpatient procedure; and 76.1% report that this issue has become an administrative burden.

CONCLUSION

The CMS clearly stated its expectation in the 2018 Outpatient Prospective Payment System Final Rule that the great majority of Medicare fee-for-service TKA patients would continue to be treated as inpatients. Nonetheless, many hospitals have decided to schedule all TKA cases as outpatients due to the 2-midnight rule despite a moratorium on recovery audits. It is the position of the American Association of Hip and Knee Surgeons that the CMS needs to provide more specific expectations concerning the needed language justifying admission or exempt TKA from the 2-midnight rule to mitigate the unintended confusion demonstrated by hospitals and some payers that has resulted from the removal of TKA from the Inpatient-Only list.