Outpatient Knee/Hip Arthroplasty Yields Fewer Adverse Events
The National Surgical Quality Improvement Program (NSQIP) database contains more than a half-million records of patients who received a total knee arthroplasty (TKA), unicompartmental knee arthroplasty (UKA), or total hip arthroplasty (THA) from 2009 through 2018. Fewer than 4% of those procedures were done in an outpatient setting, but patient demand for outpatient arthroplasty is rising rapidly.
With retrospective data like that from NSQIP, the most meaningful comparisons between inpatient and outpatient procedures come through a propensity score-matched analysis. Propensity score matching pairs up patients in each group according to multiple factors thought to influence outcome. In a recent study in The Journal of Bone & Joint Surgery, Lan et al. used propensity score matching to compare inpatient and outpatient arthroplasty in terms of adverse events and readmissions.
What the Researchers Did:
- Matched each outpatient case of TKA, UKA, and THA from the database with 4 unique inpatient cases based on age, sex, ASA class, race, BMI, type of anesthesia, and history of hypertension, smoking, congestive heart failure, and diabetes
- Compared inpatient vs outpatient rates of 30-day adverse events (both minor and severe) and readmissions
- Identified risk factors for adverse events and readmissions
What the Researchers Found:
- For all 3 arthroplasty types, patients who underwent an outpatient procedure were less likely to experience any adverse event, when compared with those who underwent an inpatient procedure.
- The above adverse-event findings held true when TKAs, UKAs, and THAs were analyzed separately.
- Outpatient procedure status was an independent protective factor against the risk of adverse events.
- For all 3 procedures, readmission rates were similar among inpatients and outpatients. (The 2 most common reasons for readmission were infections and thromboembolic events.)
- Clinicians are probably (and reasonably) selecting healthier patients to undergo outpatient procedures, but 42% of the outpatient cohort had an ASA class ≥3, and 55% had a BMI ≥30 kg/m2.
In their abstract, the authors cited “increased case throughput” as one rationale for outpatient arthroplasty, but this study provides convincing evidence that adverse-event reduction is another compelling reason for certain patients to consider outpatient knee and hip procedures.
A Deeper Dive into Diabetes and Total Joint Replacement
There are many more “types” of diabetes than the pathophysiologic designations of Type 1 and Type 2. In the December 16, 2020 issue of The Journal of Bone & Joint Surgery, Na et al. delineate 4 different diabetes categories and determine their impact on 90-day complications and readmission rates after elective total joint arthroplasty (TJA) among Medicare patients. One premise for this investigation was that, although diabetes is a known risk factor for arthroplasty complications, alternative payment models such as the federally run Comprehensive Care for Joint Replacement (CJR) program adjust their payments only in diabetes cases where the comorbidity is coded as severe.
The authors stratified diabetes into 4 groups as follows:
- No diabetes
- Controlled-uncomplicated diabetes
- Controlled-complicated diabetes
- Uncontrolled diabetes
Among the >500,000 total knee arthroplasties (TKAs) and total hip arthroplasties (THAs) analyzed, the authors found the following when comparing data from the 3 diabetes groups with the no-diabetes group:
- The odds of TKA complications were significantly higher for those with uncontrolled diabetes (odds ratio [OR] = 1.29).
- The odds of THA complications were significantly higher for those with controlled-complicated diabetes (OR = 1.45).
- The odds of readmission were significantly higher in all diabetes groups for both TKA (ORs = 1.21 to 1.48) and THA (ORs = 1.20 to 1.70).
The authors come to 3 basic conclusions based on these findings:
- The odds of hospital readmission and complications following an elective TKA or THA are increased for Medicare beneficiaries who have diabetes.
- It would be reasonable to defer arthroplasty surgery for those with uncontrolled diabetes to allow them to achieve glycemic control.
- The Centers for Medicare & Medicaid Services should include less-severe diabetes and associated systemic complications in alternative-payment model adjustments.
Click here for an “Author Insight” video about this study from co-author Annalisa Na, PhD, DPT.
TKA Cost Efficiency Is Improving, But We Can Do Better
Wide variability in the cost and quality of health care in the US has led some to describe our system as “uniquely inefficient.” Consequently, we continue to study variability intensely, especially in the realm of joint arthroplasty. In the June 3, 2020 issue of The Journal, Schilling et al. elegantly analyze the variations in 90-day episode payments made by Medicare Part A for total knee arthroplasty (TKA) from 2014 to 2016. In so doing, they provide a snapshot of hospital cost performance and, just as importantly, they offer a methodology by which to measure future hospital-level cost performance with this very popular surgery.
The authors reviewed >700,000 TKAs in the Medicare population at a time prior to the full implementation of the Comprehensive Care for Joint Replacement (CJR) model, and they ranked >3,200 hospitals within 9 US regions to determine cost performance. Schilling et al. found that during those 3 years, the mean Medicare episode payment for TKA decreased significantly, due almost entirely to a >$1,500 per-case decrease in post-acute care payments, which included lower costs for skilled nursing facilities and inpatient rehabilitation. Also decreasing during that same period were length of hospital stay and 90-day readmission rates.
These findings highlight the improvements in care and cost efficiency that were occurring even before implementation of the CJR. In a Commentary on this study, Susan Odum, PhD suggests that “the improved value of TKA illustrated by Schilling et al. includes the successful impacts of the BPCI [Bundled Payments for Care Improvement] program,” an alternative payment model that Medicare rolled out beginning in 2013.
On the other hand, the authors also reveal a persistently high degree of variability in episode payments and resource utilization both across and within geographic regions. This strongly suggests the possibility of further improvement. Regardless of which, if any, alternative payment model we participate in, everyone in the orthopaedic community should think about how to become more efficient in our delivery of musculoskeletal care. And this study provides a conceptual framework and benchmarks for identifying where the room for improvement is.
Matthew R. Schmitz, MD
JBJS Deputy Editor for Social Media
Volume-Outcome Relationships in Reverse TSA
In an OrthoBuzz post from early 2016, JBJS Editor-in-Chief Marc Swiontkowski, MD observed the following about volume-outcome relationships in total hip and total knee arthroplasty: “the higher the surgeon volume, the better the patient outcomes.”
Now, in a national database analysis of >38,200 patients who underwent a reverse total shoulder arthroplasty (RSA), Farley et al. find a similar inverse relationship between hospital volumes of this increasingly popular surgery and clinical outcomes. Reporting in the March 4, 2020 issue of JBJS, they found a similarly inverse relationship between hospital volume and resource utilization.
This study distinguishes itself with its large dataset and by crunching the data into specific hospital-volume strata for each category of clinical outcome (90-day complications, 90-day revisions, and 90-day readmissions) and resource-utilization outcome (cost of care, length of stay, and discharge disposition).
Specifically, on the clinical side, Farley et al. found the following:
- A 1.42 times increased odds of any medical complication in the lowest-volume category (1 to 9 RSAs/yr) compared with the highest-volume category (≥69 RSAs/yr)
- A 1.38 times increased odds of any readmission in the lowest-volume category (1 to 16 RSAs/yr) compared with the highest-volume category (≥70 RSAs/yr)
- A 1.88 times increased odds of any 90-day revision in the lowest-volume category (1 to 16 RSAs/yr) compared with the highest-volume category (≥54 RSAs/yr)
Here are the findings from the resource-utilization side:
- A 4.03 times increased odds of increased cost of care in the lowest-volume category (1 to 5 RSAs/yr) compared with the highest-volume category (≥106 RSAs/yr)
- A 2.26 times increased odds of >2-day length of stay in the lowest-volume category (1 to 10 RSAs/yr) compared with the highest-volume category (≥106 RSAs/yr)
- A 1.68 times increased odds of non-home discharge in the lowest-volume category (1 to 31 RSAs/yr) compared with the highest-volume category (≥106 RSAs/yr)
Farley et al. say hospital volume should be interpreted as a “composite marker” that is probably related to surgical experience, ancillary staff familiarity, and protocolized pathways. They “recommend a target volume of >9 RSAs/yr to avoid the highest risk of detrimental 90-day outcomes,” and they suggest that the outcome disparities could be addressed by “consolidation of care for RSA patients at high-performing institutions.”
Revisiting INR Targets Prior to TKA
An elevated International Normalized Ratio (INR)—a standardized gauge for how long it takes blood to clot—is rarely a good sign when someone is about to undergo an elective orthopaedic procedure. This is especially true for larger surgeries such as total hip or knee arthroplasty, in which there are already concerns about perioperative bleeding. Excessive surgery-related blood loss can lead to wound complications, increased length of hospital stay, and higher mortality rates. But what precisely constitutes an “elevated” INR? While some recommendations suggest that elective procedures be performed only when a patient’s INR is ≤1.5, the evidence supporting this recommendation, especially in the setting of total knee arthroplasty (TKA), is sparse at best.
In the March 20, 2019 issue of The Journal, Rudasill et al. use the National Surgical Quality Improvement Program (NSQIP) database to help define what “elevated” should mean in the context of TKA. They evaluated data from >21,000 patients who underwent a TKA between 2010 and 2016 and who also had an INR level reported within one day before their joint replacement. They stratified these patients based on their INR levels (≤1, >1 to 1.25, >1.25 to 1.5, and >1.5). Using multivariate regression analysis to adjust for patient demographics and comorbidities, the authors found a progressively increasing risk of bleeding requiring transfusion for each group with an INR >1 (odds ratios of 1.19, 1.29 and 2.02, respectively). Relative to patients with an INR of ≤1, Rudasill et al. also found a significantly increased risk of infection in TKA patients with an INR >1.5 (odds ratio 5.34), and an increased risk of mortality within 30 days of surgery among patients with an INR >1.25 to 1.5 (odds ratio 3.37). Lastly, rates of readmission and the length of stay were significantly increased in patients with an INR >1.25.
While there are certainly weaknesses inherent in using the NSQIP dataset, this study is the first to carefully evaluate the impact of slight INR elevations on post-TKA morbidity and mortality. While I was not surprised that increasing INR levels were associated with increased bleeding events, I was impressed by the profound differences in length of stay, infection, and mortality between patients with an INR ≤1 and those with an INR >1.25. I agree with the authors’ conclusion that “current guidelines for a target INR of <1.5 should be reconsidered for patients undergoing TKA.” Further, based on the risks highlighted in this study, prospective or propensity matched cohort studies should be performed to help determine whether anyone with an INR >1 should undergo a TKA.
Chad A. Krueger, MD
JBJS Deputy Editor for Social Media
Will New Payment Models Adversely Affect Medicaid Patient Access to THA?
Concerns have arisen that the implementation of value-based, alternative payment models pegged to “bundled” episodes of care and/or patient outcomes may make it harder for a subset of patients to access the care they need. Specifically, some surgeons may be apprehensive to treat patients who have substantial medical comorbidities or socioeconomic situations that increase their risk of postsurgical complications and poor outcomes, because these alternative payment models often financially penalize physicians and hospitals for the cost of suboptimal results. The study by Shau et al. in the December 5, 2018 issue of The Journal provides data that sharpens the horns of this dilemma.
The authors used the National Readmissions Database to perform a propensity-score-matched comparison between >5,300 patients with Medicaid payer status who underwent a primary total hip arthroplasty (THA) and an equal number of patients with other types of insurance who also underwent primary THA. Shau et al. found that Medicaid-covered THA patients had significantly increased overall readmission rates (28.8% vs 21%, p <0.001, relative risk=1.37), mean length of stay (4.5 vs 3.3 days, p <0.0001), and mean total cost of care ($71,110 vs $65,309, p <0.0001), relative to the other group. These results strongly suggest that Medicaid payer status is an independent factor associated with increased resource utilization after total hip arthroplasty.
These findings can be viewed from a couple of different perspectives. First, from a preventive standpoint, surgeons and healthcare systems providing THA for Medicaid patients may need to spend more time preoperatively optimizing these patients (both physically and psychosocially) to decrease their postoperative resource burden and increase the likelihood of a good clinical outcome. Second, these results are further proof that any fair and effective alternative payment model needs to take into consideration factors such as Medicaid payer status and patient comorbidities. If they do not, such models will actually throw access barriers in front of patients in this demographic because providers may feel that caring for them increases the likelihood of being penalized financially.
Both perspectives are valid, so Medicaid payer status is a crucial factor to consider as alternative payment programs move forward. Nowadays, controlling costs is an important goal of any healthcare delivery system, but it must not lead to unintended discrimination in patient access to care. As we create further alternative payment models and refine existing ones, we must be careful not to prioritize cost cutting ahead of equitable patient access.
Chad A. Krueger, MD
JBJS Deputy Editor for Social Media
Prescribing Opioids: Smallest Dose for Shortest Time
Some people are tired of reading and hearing about the opioid crisis in America. When this topic comes up at meetings, there are rumblings in the crowd. When it’s brought up during hospital safety briefings, there are not-so-subtle eye-rolls, and occasionally I hear frank assertions of “enough already” when new information on the topic appears in the literature. Yet, as two studies in the July 18, 2018 edition of JBJS highlight, this topic is not going away any time soon. And for good reason. We are only starting to scratch the surface of the serious unintended consequences—beyond the risk of addiction—from overly aggressive prescribing and consumption of narcotics.
The first article, by Zhu et al., directly addresses the topic of overprescribing by doctors in China. The authors evaluated how many opioid pills were given to patients who sustained fractures that were treated nonoperatively. The mean number of opioid pills patients reported consuming (7.2) was less than half the mean number prescribed (14.7). More than 70% of patients did not consume all the opioid pills they were prescribed, and 10% of patients consumed no opioids at all. Zhu et al. conclude that “if opioids are used [in this setting], surgeons should prescribe the smallest dose for the shortest time after considering the injury location and type of fracture or dislocation.”
The second article, by Weick et al., underscores the patient-outcome and societal impact of opioid use prior to total hip and knee arthroplasty. Patients from North America who consumed opioids for 60+ days prior to their joint replacement had a significantly increased risk of revision at both the 1-year and 3-year postoperative follow-ups, compared to similar patients who were opioid-naïve before surgery. Similarly, patients who used opioids for 60+ days prior to undergoing a total hip or knee arthroplasty had a significantly increased risk of 30-day readmission, compared to patients who were opioid-naïve. All these differences held when the authors made adjustments for patient age, sex, and comorbidities—meaning that tens of thousands of patients each year can expect to have worse outcomes (and add a large cost burden to the health care system) simply by being on opioid medications for two months preoperatively.
These articles address two very different research questions in two very different regions of the world, but they help expose the chasm in our knowledge surrounding opioid use and misuse. We have been prescribing patients more narcotics than they need while just starting to recognize the importance of minimizing opioid use preoperatively in an effort to maximize surgical outcomes. These two competing impulses emphasize why further opioid-related studies are important. While continuing to look at the negative effects these medications can have on patients, we have to take a hard look at our contribution to the problem.
Chad A. Krueger, MD
JBJS Deputy Editor for Social Media
More Data on Outpatient vs Inpatient Joint Replacement
In addition to the Pearl Diver-based retrospective study by Arshi et al. on one-year complications after outpatient knee replacement, the December 6, 2017 issue of JBJS contains a NSQIP-based retrospective study by Basques et al. that compares 30-day adverse events and readmissions among 1,236 patients who underwent same-day-discharge hip or knee (total or unicompartmental) arthroplasty with an equal number of propensity score-matched patients who were discharged at least 1 calendar day after the procedure.
When analyzing all three procedures together, the authors found no overall between-group differences in the rates of any adverse event (severe or minor) or readmission. However, when authors analyzed individual adverse events, the same-day group had decreased thromboembolic events and increased 30-day reoperations compared to inpatients. Analysis of individual procedures revealed an increased 30-day reoperation rate for same-day total knee arthroplasty (TKA), compared with inpatient TKA. Overall, infection was the most common reason for reoperation and readmission following same-day procedures.
As with the Arshi et al. study, the limitations of the database prevented these authors from accounting for physician or hospital volume. However, they did identify several preoperative patient characteristics that increased the risk of 30-day readmission among same-day patients, and from those findings Basques et al. concluded that “obese patients, older patients [≥85 years of age], and those with diabetes mellitus may not be appropriate candidates for same-day procedures.”
In Spinal-Metastasis Surgery, High-Volume Yields Better Outcomes
In orthopaedics, the connection between a hospital/surgeon performing a surgical procedure many times and improved outcomes has been demonstrated compellingly with total joint replacement. In the October 18, 2017 edition of JBJS, Schoenfeld et al. show that this same volume-outcome relationship holds true in the surgical treatment of spinal metastases.
The study analyzed 3,135 patients treated by 1,488 surgeons at 162 hospitals throughout Florida. Using sophisticated statistics, the authors defined high-volume surgeons as those who had performed ≥49 procedures per year and high-volume hospitals as those at which ≥167 procedures per year had been performed.
Among the entire cohort, the 90-day complication rate was 26% and the readmission rate was 43%. (Rates that high are not unexpected with such risky spinal surgeries.) Here are the findings according to surgeon volume:
- 21% complication rate for patients treated by high-volume surgeons
- 30% complication rate for patients treated by low-volume surgeons
- 37% readmission rate for patients treated by high-volume surgeons
- 47% readmission rate for patients treated by low-volume surgeons
In other words, the relative odds of complications and readmissions following operations performed by low-volume surgeons were approximately 40% higher than those following operations done by high-volume surgeons. A similar percentage difference was found between the odds at low- and high-volume hospitals. In a secondary analysis, the authors found that African Americans and Hispanics were significantly less likely than white patients to receive care from a high-volume surgeon or at a high-volume hospital.
Schoenfeld et al. state that the ideal care for patients facing surgery for spinal metastases comes from a team of experienced surgeons, medical oncologists, radiation oncologists, nurses, and support staff. They conclude that their findings “speak to the need for regionalization of subspecialty spinal oncology care as a means to optimize treatment for this cohort of patients.”
Ambulatory Shoulder Arthroplasty Is Safe
In the April 19, 2017 issue of The Journal, Cancienne et al. compare complication and readmission rates for patients undergoing ambulatory shoulder arthroplasty with those among patients admitted as hospital inpatients postoperatively. Because the analysis was based on data from a large national insurer, we can be quite sure of appropriate coding and accurate data capture.
Similar to our recent report regarding outpatient hand and elbow surgery, in no instance were complications present at a significantly higher rate in the patients who underwent ambulatory shoulder arthroplasty, and the rate of hospital readmission after discharge was not significantly different at 30 or 90 days between the two cohorts.
This definitely is a tip of the hat to orthopaedic surgeons, nurses, and anesthesiologists, who are making sound decisions regarding which patients are appropriate for outpatient arthroplasty. Cancienne et al. found that obesity and morbid obesity were significant demographic risk factors for readmission among the ambulatory cohort, and they also identified the following comorbidities as readmission risk factors in that group:
- Diabetes
- Peripheral vascular disease
- Congestive heart failure
- Chronic lung disease
- Depression
- Chronic anemia
These results offer further documentation regarding the shift away from hospital-based care after orthopaedic surgery. Those of us who perform surgery in dedicated orthopaedic centers as well as general hospital operating rooms understand the concepts of efficiency, focus, maintenance of team skills, and limiting waste. Those objectives in large part drive the move to outpatient surgery. But patients, who almost always prefer to be at home and sleep in their own beds (or recliners in the case of shoulder replacement), may be an even more powerful driver of ambulatory care in the future.
Major advances in postoperative pain management are great enablers in this regard, and I believe the trend will continue. I envision a day when the only patients admitted to hospitals after orthopaedic surgery are those with unstable medical issues who potentially may need ICU care postoperatively.
Marc Swiontkowski, MD
JBJS Editor-in-Chief
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