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

Lower Revenue Surplus in Medicare Advantage Versus Private Commercial Insurance for Total Joint Arthroplasty: An Analysis of a Single Payor Source at One Institution

BACKGROUND

Since the Affordable Care Act was passed in 2010, reductions in Medicare reimbursement have led to larger discrepancies between the relative cost of Medicare patients and privately insured patients. The purpose of this study was to compare reimbursement between Medicare Advantage and other insurance plans in patients undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA).

METHODS

Patients of a single commercial payor source who underwent primary unilateral TKA or THA at 1 institution between the dates of January 4 and June 30, 2021, were included (n = 833). Variables included insurance type, medical comorbidities, total costs, and surplus amounts. The primary outcome measure was revenue surplus between Medicare Advantage and Private Commercial plans. t-tests, Analyses of Variance, and Chi-Squared tests were used for analysis. A THA represented 47% of cases and a TKA 53%. Of these patients, 31.5% had Medicare Advantage and 68.5% had Private Commercial insurance. Medicare Advantage patients were older and had higher medical comorbidity risk for both TKA and THA.

RESULTS

Significant differences were observed in medical costs between Medicare Advantage and Private Commercial insurance for THA ($17,148 versus $31,260, P < .001) and TKA ($16,723 versus $33,593, P < .001). Additionally, differences were seen in surplus amounts between Medicare Advantage and Private Commercial insurance for THA ($3,504 versus $7,128, P < .001) and TKA ($5,581 versus $10,477, P < .001). Deficits were higher in Private Commercial patients undergoing TKA (15.2 versus 6%, P = .001).

CONCLUSION

The lower average surplus associated with Medicare Advantage plans may lead to financial strain on provider groups who care for these patients and face additional overhead costs.

Morbidly Obese Patients Undergoing Unicompartmental Knee Arthroplasty Compared to Total Knee Arthroplasty: A Retrospective Case-Controlled Analysis

BACKGROUND

In this study, we assess the effects that morbid obesity (body mass index (BMI) ≥ 40) has on: (1) Ninety-day medical complications and readmission rates; (2) costs of care and lengths of stay (LOS); and (3) 2-year implant complications in patients undergoing unicompartmental knee arthroplasty (UKA) versus total knee arthroplasty (TKA).

METHODS

A retrospective query of TKA and UKA patients were identified using a national database. Morbidly obese UKA patients were matched 1:5 to morbidly obese TKA patients by demographic and comorbidity profiles. Subgroup analyses were conducted using the same process between morbidly obese UKA patients and BMI <40 TKA patients, as well as to BMI <40 UKA patients.

RESULTS

Morbidly obese patients who underwent UKA had significantly fewer medical complications, readmissions, and periprosthetic joint infections than TKA patients; however, UKA patients had greater odds of mechanical loosening (ML). The TKA patients had significantly longer LOS (3.0 versus 2.4 days, P < .001), as well as significantly greater costs of care than UKA patients ($12,869 versus $7,105). Morbidly obese UKA patients had similar rates of medical complications, and significantly lower readmissions, decreased LOS, and decreased costs when compared to TKA patients who had a BMI <40.

CONCLUSION

In patients who have morbid obesity, complications were decreased in UKA compared to TKA. Moreover, morbidly obese UKA patients had lower medical utilizations and similar complication rates when compared to TKA patients with the recommended cutoff of BMI <40. However, UKA patients had greater rates of ML than TKA patients. A UKA may be an acceptable treatment option for unicompartmental osteoarthritis in morbidly obese patients.

Freestanding Ambulatory Surgery Centers and Patients Undergoing Outpatient Knee Arthroplasty

Importance

In 2018, Medicare removed total knee arthroplasty from the list of inpatient-only procedures, resulting in a new pool of patients eligible for outpatient total knee arthroplasty. How this change was associated with the characteristics of patients undergoing outpatient knee arthroplasty at hospital-owned surgery centers (HOSCs) vs freestanding ambulatory surgery centers (FASCs) is unknown.

Objectives

To describe the characteristics of patients undergoing outpatient, elective total and partial knee arthroplasty in 2017 and 2018 and to compare the cohorts receiving treatment at FASCs and HOSCs.

Design, Setting, and Participants

This observational retrospective cohort study included 5657 patients having elective, outpatient partial and total knee arthroplasty in the Florida and Wisconsin State Ambulatory Surgery Databases in 2017 and 2018. Prior admissions were identified in the State Inpatient Database. Statistical analysis was performed from March to June 2022.

Main Outcomes and Measures

Characteristics of patients undergoing surgery at a FASC vs a HOSC in 2017 and 2018 were compared.

Results

A total of 5657 patients (mean [SD] age, 64.2 [9.9] years; 2907 women [51.4%]) were included in the study. Outpatient knee arthroplasties increased from 1910 in 2017 to 3747 in 2018 and were associated with an increase in total knee arthroplasties (474 in 2017 vs 2065 in 2018). The influx of patients undergoing outpatient knee arthroplasty was associated with an amplification of differences between the patients treated at FASCs and the patients treated at HOSCs. Patients with private payer insurance seen at FASCs increased from 63.4% in 2017 (550 of 867) to 72.7% in 2018 (1272 of 1749) (P < .001), while the percentage of patients with private payer insurance seen at HOSCs increased, but to a lesser extent (41.6% [427 of 1027] in 2017 vs 46.4% [625 of 1346] in 2018; P < .001). In 2017, the percentages of White patients seen at FASCs and HOSCs were similar (85.0% [737 of 867] vs 88.2% [906 of 1027], respectively); in 2018, the percentage of White patients seen at FASCs had increased and was significantly different from the percentage of White patients seen at HOSCs (90.6% [1585 of 1749] vs 87.9% [1183 of 1346]; P = .01). Both types of facilities saw an increase from 2017 to 2018 in the percentage of patients from communities of low social vulnerability, but this increase was greater for FASCs (FASCs: 6.7% [58 of 867] in 2017 vs 33.9% [593 of 1749] in 2018; HOSCs: 7.6% [78 of 1027] in 2017 vs 21.2% [285 of 1346] in 2018). Finally, while FASCs and HOSCs had cared for a similar portion of patients with prior admissions in 2017 (7.8% [68 of 867] vs 9.4% [97 of 1027], respectively; P = .25), in 2018, FASCs cared for fewer patients with prior admissions than HOSCs (4.0% [70 of 1749] vs 8.1% [109 of 1346]; P < .001).

Conclusions

This study suggests that the increase in the number of patients undergoing outpatient knee arthroplasty in 2018 corresponded to FASCs treating a greater share of patients who were White, covered by private payer insurance, and healthier. These findings raise a concern that as more operations transition to the outpatient setting, variability in access to FASCs may increase, leaving hospital-owned centers to bear a greater share of the burden of caring for more vulnerable patients with more severe illness.

Unicompartmental Knee Arthroplasty Is Cost-Effective in an Outpatient Setting

INTRODUCTION

Increasingly, unicompartmental knee arthroplasty (UKA) is being performed on an outpatient basis, with the growing utilization of ambulatory surgery centers (ASCs). The purpose of this study was to compare the costs of UKAs performed in an ASC to UKAs done in a hospital, either on an outpatient or inpatient basis.

METHODS

This study involved three matched groups, each with 50 consecutive patients, undergoing UKA either on an outpatient basis in an ASC or a community hospital, or who were admitted overnight to the same community hospital. Identical perioperative analgesic regimens and care protocols were used in each group. The primary outcomes evaluated included direct facility costs. Secondary outcomes were postoperative complications and readmissions.

RESULTS

Average age, gender ratio, and comorbidities were similar in all three cohorts. Only two patients in the study experienced complications and these were without secondary adverse consequences. Mean costs were substantially reduced when UKAs were performed in an ASC ($9,025) compared to a community hospital on either an outpatient ($12,032) or inpatient basis ($14,542).

CONCLUSION

UKA can be safely performed in the outpatient setting, in appropriately selected patients, at substantial cost savings, particularly when performed in an ASC.

Identifying and Creating Value for Employed Arthroplasty Surgeons in an Era of Decreasing Reimbursement

Recent regulatory changes made by the Center for Medicare and Medicaid Services (CMS) will result in a 9% decrease in reimbursement for hip and knee replacements by the end of 2022. Combining this with CMS's recent removal of total knee and total hip arthroplasty from the inpatient-only list has begun to take effect on the bottom line for hospital systems, which now employ around 50% of the arthroplasty community. Employed joint replacement surgeons should continue to innovate and be leaders within their hospital systems in the outpatient and ambulatory surgery space to recoup lost value, increase autonomy, and should be compensated for this work. Employed arthroplasty surgeon leaders can better align goals with and control the narrative in the C-suite to redefine their value as the most consistent, dependable, and transparent department within a larger health system or corporate medical group.