Is Same-Day Discharge Safe for Total Joint Arthroplasty Patients?
The COVID-19 pandemic, removal of total hip and total knee arthroplasty from the Centers for Medicare and Medicaid Services’ Inpatient-Only List, and interest from patients have combined to drive the increase in outpatient procedures. What does the literature say about same-day discharge in total joint arthroplasty?
Shankar Narayanan, MD; Thomas Schmicker, MD; and Ran Schwarzkopf, MD, MSc
Hip and knee arthroplasty are among the most common and most successful surgeries performed worldwide. In the US alone, it is estimated that by the year 2030: 
- The number of total hip arthroplasties (THA) performed annually will increase by 71% to 635,000
- The number of total knee arthroplasties (TKA) performed annually will increase by 85% to 1.26 million
Hospital length of stay following total joint arthroplasty (TJA) has decreased dramatically, from 3 weeks in the 1980s to only 1 or 2 days today.  However, pressure on hospital resources during the early months of the COVID-19 pandemic challenged orthopaedic surgeons to continue offering elective procedures like THA and TKA without further stressing the inpatient resources needed to manage critically ill COVID patients.
One option was same-day discharge. Prior to the pandemic, several surgeons had pioneered safe pathways for outpatient TJA. These pathways became more mainstream during the pandemic and have revolutionized the way care is delivered to patients with hip and knee osteoarthritis, making same-day discharge a reality for many TJA patients. [3,4]
The trend is expected to continue: It is estimated that by 2026, 51% of all patients undergoing TJA will be discharged to home the same day as surgery, a 77% growth in same-day discharge. Just 3% growth is expected for patients who stay in the hospital overnight. 
In 2018, the Centers for Medicare and Medicaid Services (CMS) removed TKA (Current Procedural Terminology [CPT] code 27447) from the Medicare Inpatient-Only (IPO) List.  Two years later, they removed THA (CPT 27130) for the IPO list, meaning that patients who received Medicare benefits could be operated on at an inpatient or outpatient facility. 
However, many patients who had an “outpatient” THA or TKA were still being admitted to the hospital for 23 hours or less for overnight monitoring; they were not being discharged the same day as their surgery. That all changed in mid-2020 due to the COVID-19 pandemic, and true same-day discharge programs for TJA began to be widely implemented so that elective procedures could resume.
As same-day discharge programs are being established with increasing frequency at hospitals and ambulatory surgery centers (ASCs) across the country, it’s important to note that cost concerns may be driving CMS’s action. As the population ages, the burden of OA in the US is increasing, which will increase the number of Medicare patients undergoing joint replacement surgery. Faced with this future, CMS has looked for ways to cut healthcare costs, such as allowing Medicare beneficiaries to undergo hip and knee arthroplasty on an outpatient basis, in ambulatory surgery centers.
A 2014 study that examined the cost of outpatient versus inpatient TKA found that same-day discharge reduced costs approximately 30% compared with inpatient procedures per episode of care.  In a case control study, same-day discharge of THA patients saved approximately $4000 per patient compared with THA that included an inpatient stay. 
Although the push for same-day discharge may have a strong economic component, there is some good news: Same-day discharge patients are generally happier than inpatients. In a study of 166 THA and TKA patients – 102 inpatient and 64 same-day discharge patients – patients in the same-day discharge group tended to be more satisfied with their care than patients who stayed overnight in the hospital after their procedure. 
Addressing Safety Issues
With same-day discharge demonstrating cost benefits and greater patient satisfaction, the next question is, can same-day discharge of hip and knee arthroplasty patients be implemented safely?
To begin answering that question, a high-volume TJA surgeon and a board-certified internist developed a scoring system in 2017 – the Outpatient Arthroplasty Risk Assessment (OARA) score – that was based on medical comorbidities in 9 organ systems.  They validated the OARA score in 1120 TJA patients, demonstrating that this screening tool was more predictive of whether a patient could be discharged the same day as surgery than American Society of Anesthesiologist (ASA) class or Charlson Comorbidity Index. 
The OARA screening tool was then validated at a separate institution in a study of 322 consecutive patients undergoing  THA. The patients were divided into 2 groups according to the institution’s discharge pathways: those expected to be discharged the same day as surgery and those expected to be discharged the next day. The goal was to determine the accuracy of the OARA screening tool in predicting length of stay. The researchers found the tool to have a high positive predictive value for patients in the same-day discharge group who left on POD0. 
A randomized controlled trial conducted at 2 high-volume institutions compared inpatient overnight stay versus same-day discharge of patients undergoing THA by direct anterior approach. No differences were observed between the groups in the number of reoperations, hospital readmissions, or emergency department visits. This was the first study to demonstrate the safety of same-day discharge in a direct comparison of inpatients versus patients discharged the same day as TJA. 
Risk of Complications
Total hip and total knee arthroplasty are major surgical procedures, and as with any surgery, a small percentage of patients will experience a serious, possibly life-threatening, complication after surgery. With outpatient surgery, these complications can occur without the safety net of the hospital.
A study by Johnson et al  demonstrated that catastrophic complications after TJA reach their peak a few days after surgery and that increasing age and ASA score are risk factors. Compared with patients who had an inpatient stay, patients who were discharged the same day as surgery experienced death as a greater proportion of their complications, which Johnson et al  said could have been due to the lack of rapid intervention available at home.
Lovecchio et al  compared complications in same-day discharge patients with patients who were on a “fast-track” protocol and had a length of stay of less than 2 days. When patients were propensity-matched, same-day discharge patients were more likely to have a post-discharge complication and had a higher rate of reoperation. 
DeMik et al  examined outcomes before and after TKA was removed from the IPO List, using the National Surgical Quality Improvement Program database. They found no increase in 30-day complication, readmission, or reoperation rates for 2018, the year TKA was removed from the IPO list, compared with the 3 prior years (2015-2017). The study authors said their findings suggest that “surgeons have continued to exercise sound judgment as to what patients can safely undergo outpatient TKA.” 
A recent study using data from the Kaiser Permanente Total Joint Replacement Registry suggests that even high-risk patients may be candidates for same-day discharge.  About one third of the 15,000 high-risk TKA and THA patients (ASA classification of 3 or more) included in the registry had been discharged the same day as surgery, with no increased risk of complications, emergency department visits, or unplanned hospital readmissions at 90 days after discharge. 
Patient and Surgeon Selection
Proponents say that success of same-day discharge has been stalled by the inability to reliably select appropriate patients. However, the profile of the appropriate same-day discharge candidate is debatable: While some study authors say that any patient who is not in organ failure may be a candidate,  others believe patients should be risk-stratified according to their comorbidities, such as the OARA screening tool discussed above. [11-13]
Multiple studies have demonstrated that even after stringent selection criteria are applied, patients who were supposed to be released the same day as surgery end up staying overnight after TJA – ie, failure to launch. In a study by Lieberman et al,  16.6% of same-day discharge patients experienced a failure to launch. Risk factors for an overnight stay included age over 70, more than 2 self-reported allergies, and use of opioids preoperatively, although patients in the study by Lieberman et al  primarily stayed overnight due to anesthesia-related issues, such as a long-acting spinal and hypotension.
Less talked about is surgeons’ self-selection for discharging patients the same day as surgery. Rozell et al  assert that a surgeon must engage in an honest assessment of their own skill. Surgeons who are more likely to safely discharge patients the day of surgery are those who are able to “deliver a consistent product” to the recovery room, with brief operative times, reasonable blood loss, and a low-rate of intraoperative complications. 
Same-day discharge has been shown to be a viable option for TJA patients. In the past 18 months, it has become a way for surgeons to continue performing these elective procedures in patients with debilitating osteoarthritis of the hip and knee without utilizing hospital resources needed for critically ill patients.
There are financial drivers to the move toward same-day discharge as well, notably the decision by CMS to remove TKA and THA from the IPO List, thus moving many Medicare beneficiaries to the outpatient/ambulatory setting. Research has shown outpatient care for knee and hip arthroplasty patients to be less costly than inpatient care, [8,9] potentially saving CMS millions of dollars in reimbursement to hospitals, ambulatory surgery centers, and surgeons.
Of course, same-day discharge is not safe for every TJA patient. Determining which patients are appropriate candidates for discharge the day of surgery requires careful assessment of each patient’s risk factors and a plan for modifying as many of those as possible. The OARA screening tool is a good option to use in this evaluation process, with independent research validating its positive predictive value in identifying candidates for same-day discharge. [11-13]
Research on complications post-discharge has been mixed. Recent studies, however, have shown no difference in complications, readmissions, and emergency department visits for patients discharged the same day as surgery compared with those staying at least 1 night in the hospital. [14,17,18]
Although patients seem to be generally satisfied with same-day discharge, some surgeons report greater administrative burden on their staff due to issues with preauthorization for inpatient stays, questions about unexpected copays from patients, and confusion over CMS audits.  Clearly, CMS should provide more guidance on these issues to help surgeons and their staff navigate the new reality of outpatient TKA and THA among the Medicare population.
Shankar Narayanan, MD, and Thomas Schmicker, MD, are NYU/ISK Adult Reconstruction Fellows at NYU Langone Health, New York, New York. Ran Schwarzkopf, MD, MSc, is Professor of Orthopedic Surgery, Associate Chief of the Division of Adult Reconstruction, Director of the Adult Reconstruction Research Center, and Associate Director of the Orthopedic Surgery Residency Program at NYU Langone Health, New York, New York.
Disclosures: The authors have no disclosures relevant to this article.
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