The Effects of Revision Total Hip Arthroplasty on Medicare Spending and Beneficiary Outcomes: Implications for the Comprehensive Care for Joint Replacement Model

Inpatient Hospital Costs, Emergency Department Visits, and Readmissions for Revision Hip and Knee Arthroplasty

BACKGROUND

Revision total hip arthroplasty (THA) and total knee arthroplasty (TKA) tremendously burden hospital resources. This study evaluated factors influencing perioperative costs, including emergency department (ED) visits, readmissions, and total costs-of-care within 90 days following revision surgery.

METHODS

A retrospective analysis of 772 revision TKAs and THAs performed on 630 subjects at a single center between January 2007 and December 2019 was conducted. Cost data were available from January 2015 to December 2019 for 277 patients. Factors examined included comorbidities, demographic information, preoperative Anesthesia Society of Anesthesiologists score, implant selection, and operative indication using mixed-effects linear regression models.

RESULTS

Among 772 revisions (425 THAs and 347 TKAs), 213 patients required an ED visit, and 90 required hospital readmission within 90 days. There were 22.6% of patients who underwent a second procedure after their initial revision. Liver disease was a significant predictor of ED readmission for THA patients (multivariable odds ratio [OR]: 3.473, P = .001), while aseptic loosening, osteolysis, or instability significantly reduced the odds of readmission for TKA patients (OR: 0.368, P = .014). In terms of ED visits, liver disease increased the odds for THA patients (OR: 1.845, P = .100), and aseptic loosening, osteolysis, or instability decreased the odds for TKA patients (OR: 0.223, P < .001). Increased age was associated with increased costs in both THA and TKA patients, with significant cost factors including congestive heart failure for TKA patients (OR: $7,308.17, P = .004) and kidney disease for THA patients. Revision surgeries took longer than primary ones, with TKA averaging 3.0 hours (1.6 times longer) and THA 2.8 hours (1.5 times longer).

CONCLUSIONS

Liver disease increases ED readmission risk in revision THA, while aseptic loosening, osteolysis, or instability decreases it in revision TKA. Increased age and congestive heart failure are associated with increased costs. These findings inform postoperative care and resource allocation in revision arthroplasty.

LEVEL OF EVIDENCE

Economic and Decision Analysis, Level IV.

The True Dislocation Incidence following Elective Total Hip Replacement in Sweden: How Does It Relate to the Revision Rate?

(1) Background: The true dislocation incidence following THA is difficult to ascertain in population-based cohorts. In this study, we explored the cumulative dislocation incidence (CDI), the relationship between the incidence of dislocation and revision surgery, patient- and surgery-related factors in patients dislocating once or multiple times, and differences between patients being revised for dislocation or not. (2) Methods: We designed an observational longitudinal cohort study linking registers. All patients with a full dataset who underwent an elective unilateral THA between 1999 and 2014 were included. The CDI and the time from the index THA to the first dislocation or to revision were estimated using the Kaplan-Meier (KM) method, giving cumulative dislocation and revision incidences at different time points. (3) Results: 136,810 patients undergoing elective unilateral THA were available for the analysis. The 30-day CDI was estimated at 0.9% (0.9-1.0). The revision rate for dislocation throughout the study period remained much lower. A total of 51.2% (CI 49.6-52.8) suffered a further dislocation within 1 year. Only 10.9% of the patients with a dislocation within the first year postoperatively underwent a revision for dislocation. (4) Discussion: The CDI after elective THA was expectedly considerably higher than the revision incidence. Further studies investigating differences between single and multiple dislocators and the criteria by which patients are offered revision surgery following dislocation are urgently needed.

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.

Early Total Hip Arthroplasty is a Cost-Effective Treatment for Severe Radiographic Slipped Capital Femoral Epiphysis Over an Individual's Lifetime

BACKGROUND

Slipped capital femoral epiphysis (SCFE) causes degenerative changes warranting total hip arthroplasty (THA) in approximately 50% of patients by age 60 years. For severe SCFE, a reorienting intertrochanteric osteotomy (ITO) following in situ pinning (ISP) can decrease impingement with hip flexion, but by altering proximal femoral geometry, complicates subsequent conversion THA. We hypothesized that increasing implant survivorship would affect the most cost-effective treatment strategy (ISP followed by ITO [ISP + ITO] with later THA versus ISP alone [ISPa] with earlier THA) over a patient's lifetime.

METHODS

A state-transition Markov model was constructed to analyze the cost-effectiveness of either ISPa or ISP + ITO over a 60-year time horizon for children who have severe, stable SCFE. Transition probabilities associated with implant and native hip survivorship, state utilities, and costs were derived from the literature. Sensitivity analyses assessed the model robustness. Incremental cost-effectiveness ratios (ICERs) were compared to a societal willingness to pay (WTP) of $100,000 per quality-adjusted life year (QALY).

RESULTS

Over a 60-year horizon, ISPa was costlier ($291,836) than ISP + ITO ($75,227) but achieved overall better outcomes (51.4 QALYs ISPa versus 48.7 QALYs ISP + ITO), rendering ISPa cost-effective with an ICER of $80,980/QALY. Implant survivorship and time horizon were sensitive variables.

CONCLUSION

Based upon current implant performance, ISPa with subsequent earlier THA is cost-effective when considering an individual's life expectancy and thereby deserves consideration in patients who have severe SCFE. Without clear level 1 clinical data, our economic model considers a difficult problem, while providing families and clinicians with a framework for understanding treatment options.

LEVEL OF EVIDENCE

Economic and decision analysis, Level III.

Contemporary Outpatient Arthroplasty Is Safe Compared with Inpatient Surgery: A Propensity Score-Matched Analysis of 574,375 Procedures

BACKGROUND

Outpatient joint arthroplasty is a potential modality for increased case throughput and is rising in demand. However, we are aware of no study that has compared outcomes between risk-matched outpatient and inpatient procedures within the last 7 years. The aims of this study were to compare matched patient cohorts who underwent outpatient or inpatient joint arthroplasty in terms of 30-day adverse events and readmission rates.

METHODS

From the National Surgical Quality Improvement Program database, we identified patients who underwent primary total hip arthroplasty (THA), primary total knee arthroplasty (TKA), and primary unicompartmental knee arthroplasty (UKA) from 2009 to 2018. Using 10 perioperative variables, patients who underwent an outpatient procedure were 1:4 propensity score-matched with patients who underwent an inpatient procedure. The rates of 30-day adverse events and readmission were compared using the McNemar test. The risk factors for adverse events and readmissions were identified using multivariate regression.

RESULTS

Of 574,375 patients identified, 21,506 (3.74%) underwent an outpatient procedure. After propensity score matching, an outpatient joint arthroplasty was associated with a lower rate of adverse events (3.18% compared with 7.45%; p < 0.001). When assessed individually, outpatient TKA (3.15% compared with 8.11%; p < 0.001), THA (4.94% compared with 10.05%; p < 0.001), and UKA (1.78% compared with 3.39%; p < 0.001) were all associated with fewer adverse events overall and there was no difference in the rate of 30-day readmission, when compared with inpatient analogs. Outpatient joint arthroplasty was an independent factor for lower adverse events (odds ratio [OR], 0.407 [95% confidence interval (CI), 0.369 to 0.449]; p < 0.001), with no increase in the risk of readmission (OR, 1.004 [95% CI, 0.878 to 1.148]; p = 0.951).

CONCLUSIONS

Contemporary outpatient joint arthroplasty demonstrated lower rates of adverse events with no increased rate of 30-day readmission when compared with risk-matched inpatient counterparts. Although multiple factors should guide the decision for the site of care, outpatient arthroplasty may be a safe alternative to inpatient arthroplasty.

LEVEL OF EVIDENCE

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

How Are We Measuring Cost-Effectiveness in Total Joint Arthroplasty Studies? Systematic Review of the Literature

BACKGROUND

As volumes of total hip arthroplasty (THA) and total knee arthroplasty (TKA) continue to rise, it is important to understand their economic impact. No systematic review on cost-effectiveness of THA/TKA has been performed since 2016 despite recent changes in the healthcare environment. The purpose of the study is to provide a contemporary analysis of the cost-effectiveness of total joint arthroplasty and the use of quality-adjusted life years (QALYs).

METHODS

A systematic review was performed from 2005 to 2020. Online databases (OVID Medline, PubMed, Cost-Effectiveness Analysis Registry, Google Scholar, Elton B. Stephens Co) were queried to identify economic analyses that evaluated the cost-effectiveness of THA/TKA.

RESULTS

In total, 38 studies met the screening criteria. Study designs were primarily Markov models (68%), cohort studies (16%), and randomized trials (8%). Most studies adopted either a societal perspective (45%) or a health system perspective (39%). Analysis revealed that THA/TKA was strongly cost-effective compared to nonsurgical treatment. THA/TKA procedures that were not delayed were more cost-effective than delayed intervention. The majority of studies used QALYs as the primary quality metric (82%); in all these studies there was a significant improvement in QALYs gained.

CONCLUSION

Given the high economic impact of arthroplasty, ongoing assessment of cost-effectiveness is needed. Twenty-four percent of studies included in this systematic review were published in the last 4 years of this 15-year study period, highlighting the need for continuous assessment of aggregate data. Future studies should incorporate the cost-effectiveness of THA and TKA with respect to the work-value provided by surgeon providers to support health policy and reimbursement.

Evolving Outcome Measures in Total Knee Arthroplasty: Trends and Utilization Rates Over the Past 15 Years

BACKGROUND

Patient-reported outcome metrics and reporting are important for demonstrating value associated with total knee arthroplasty (TKA). This review studied the patient-reported outcome utilization trends as reported within the TKA literature over a 15-year period.

METHODS

A PubMed search of all manuscripts related to TKA from January 2005 to December 2019 was performed. Descriptive statistics were used for individual outcome metrics as proportions of total article publications focusing on TKA outcomes. Linear regressions analysis was performed to demonstrate significant changes in utilization rates over time.

RESULTS

There was a significant overall increase in studies utilizing outcome metrics between 2005 and 2019 (16.1%-45.0%; P < .001; R² = 98.7%). Within joint-specific metrics (2005-2019), use of Knee Disability and Osteoarthritis Outcome score increased (0%-14.8%; P < .001); while use of Knee Society Knee Scoring System decreased (55.2%-35.4%; P = .007). Of the studies reporting general health, use of the Forgotten Joint Score-12 decreased (100%-66.7% from 2014 to 2019; P = .006), and Patient-Reported Outcome Measurement Information System Global-10 increased (0%-21.4% from 2005 to 2019; P < .001). In the quality of life subcategory (2005-2019), EuroQol 5-Dimension Health Outcome Survey increased in usage (14.3%-28.0%; P < .001), while Short Form-36 use decreased (85.7%-36.6%; P < .001).

CONCLUSION

Although utilization of outcome metrics has significantly increased over the last 15 years in the TKA literature, there still exists considerable heterogeneity of outcome metrics. This lack of consensus may impede comparisons of studies for clinical and research purposes, as well as hinder cross-walk of outcome tools over time. Further study is needed to identify ideal global and joint-specific tools, while balancing issues like ease of use and utility in specific populations such as the young and highly active.

A cost-effectiveness assessment of dual-mobility bearings in revision hip arthroplasty

Aims

The rate of dislocation when traditional single bearing implants are used in revision total hip arthroplasty (THA) has been reported to be between 8% and 10%. The use of dual mobility bearings can reduce this risk to between 0.5% and 2%. Dual mobility bearings are more expensive, and it is not clear if the additional clinical benefits constitute value for money for the payers. We aimed to estimate the cost-effectiveness of dual mobility compared with single bearings for patients undergoing revision THA.

Methods

We developed a Markov model to estimate the expected cost and benefits of dual mobility compared with single bearing implants in patients undergoing revision THA. The rates of revision and further revision were calculated from the National Joint Registry of England and Wales, while rates of transition from one health state to another were estimated from the literature, and the data were stratified by sex and age. Implant and healthcare costs were estimated from local procurement prices and national tariffs. Quality-adjusted life-years (QALYs) were calculated using published utility estimates for patients undergoing THA.

Results

At a minimum five-year follow-up, the use of dual mobility was cost-effective with an estimated incremental cost-effectiveness ratio (ICER) of between £3,006 and £18,745/QALY for patients aged < 55 years and between 64 and 75 years, respectively. For those aged > 75 years dual mobility was only cost-effective if the timeline was beyond seven years. The use of dual mobility bearings was cost-saving for patients aged < 75 years and cost-effective for those aged > 75 years if the time horizon was beyond ten years.

Conclusion

The use of dual mobility bearings is cost-effective compared with single bearings in patients undergoing revision THA. The younger the patient is, the more likely it is that a dual mobility bearing can be more cost-effective and even cost-saving. The results are affected by the time horizon and cost of bearings for those aged > 75 years. For patients aged > 75 years, the surgeon must decide whether the use of a dual mobility bearing is a viable economic and clinical option.

Cite this article: Bone Joint J 2020;102-B(9):1128–1135.

MOTS-c inhibits Osteolysis in the Mouse Calvaria by affecting osteocyte-osteoclast crosstalk and inhibiting inflammation

The Mitochondrial-derived peptide MOTS-c has recently been reported as a 16-amino acid peptide regulating metabolism and homeostasis in different cells. However, its effects on immune cells and bone metabolism are rarely reported. Here we demonstrate that MOTS-c treatment in ultra-high molecular weight polyethylene (UHMWPE) particle-induced osteolysis mouse model alleviated bone erosion and inflammation. MOTS-c increased osteoprotegerin (OPG)/ receptor activator of nuclear factor kappa-B ligand (RANKL) ratio in osteocytes, leading to inhibition of osteoclastogenesis. In primary bone marrow macrophages (BMMs) MOTS-c alleviated STAT1 and NF-κB phosphorylation triggered by UHMWPE particles. Promoting ROS production or suppressing peroxisome proliferator-activated receptor γ (PPARγ) coactivator-1α (PGC-1α) by adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) repression blocked these anti-inflammatory effects of MOTS-c treatment. Taken together, these findings provide evidence that the small peptide inhibits osteoclastogenesis by regulating osteocyte OPG/RANKL secretion and suppressing inflammation via restraining NF-κB and STAT1 pathway. Moreover, its effects on NF-κB activation is dependent on the AMPK-PGC-1α-ROS axis, suggesting its potential use in osteolysis and other inflammation disorders.