Introduction
The popularity of same-day discharge total joint arthroplasty (TJA) continues to increase, as does the number of these procedures being performed at freestanding ambulatory surgery centers (ASCs). , These procedures are being performed successfully and safely both in the hospital outpatient department (HOPD) and ambulatory surgical setting. There are numerous reasons for the continuous shift from the inpatient to outpatient setting for total joints. Perhaps the greatest driver of this shift are the legislative changes made by the Centers for Medicare & Medicaid Services (CMS). Starting in January 2018, total knee arthroplasty (TKA) was removed from the inpatient-only list; total hip arthroplasty (THA) was removed from the inpatient-only list in 2020. CMS also added TKA to the ASC-covered surgical procedure list, with THA expected to follow in 2021. The changes made by the CMS have paved the way for private payers to continue to drive joint arthroplasty to the ambulatory environment. In addition to the payer, there are several surgeon- and patient-driven reasons for this shift. ASCs allow surgeons to operate in an efficient environment that allows for increased case volume while often giving the surgeon more autonomy and operational input than the hospital. Surgeons may have an opportunity to participate as an equity shareholder in an ASC, creating potential financial incentives. From the patient perspective, the ASC creates an enhanced level of service, a more convenient and efficient surgical experience for themselves and their family, and an option to avoid the traffic of a traditional hospital. The result has been very high patient satisfaction scores in the ASC environment ( Fig. 4.1 ).

With the rise in outpatient arthroplasty, there has been a growing interest in the perioperative considerations and complications specifically related to same-day discharge arthroplasty. The purpose of this chapter is to discuss the challenges associated with performing total joint arthroplasty in an outpatient setting from preoperative patient selection, perioperative complications, and postoperative follow-up.
Preoperative Considerations—Patient Selection and Education
A key factor in limiting complications and maximizing safety during TJA in an outpatient setting is appropriate patient selection. The process of appropriate patient selection should aim to identify those patients that will be successfully discharged home on the day of surgery. Equally important is creating a process to identify patients at risk for return to the emergency department (ED) or hospital readmission. While these two issues are related, there is an important distinction between patients who are willing and able to go home on the day of surgery and those who are initially able to go home but are subsequently readmitted for management of medical comorbidities, postoperative pain, or surgical complications. Understanding the inherent difference is necessary because it requires assessing different sets of patient characteristics and a more comprehensive analysis of not just the patient but the patient’s environment and social situation.
In order to identify those patients who are most likely to have a successful same-day discharge, some authors have focused on specific demographic variables, , while others have developed risk assessment tools that incorporate a number of variables into a calculated score. , Demographic variables associated with successful same-day discharge include lower body mass index (BMI), fewer self-reported allergies, lower American Society of Anesthesiologists (ASA) score, and male gender. Other studies advocate for a risk assessment score that accounts for both the presence and severity of a range of medical comorbidities, an approach that allows for a nuanced assessment of a patient’s medical comorbidities and associated perioperative risk. Meneghini et al. describe the outpatient arthroplasty risk assessment (OARA) metric, which creates a total score based on a number of the aforementioned variables. The OARA has shown promise and has been reported to outperform both the Charlson comorbidity index (CCI) and the ASA score in predicting successful same-day discharge. , This specific OARA screening tool has been externally validated in one independent study by Kim et al., which found similar superiority of the OARA tool compared with either the ASA score or CCI in predicting successful same-day discharge.
Lately, there has been a strong association between outpatient TJA and ASCs. It is true that there has been a migration of outpatient cases to the freestanding ASC environment, but there are still a large number of patients discharged the same day from the hospital and HOPDs. Once a patient has been properly evaluated and found to meet outpatient selection criteria, the next step in the process is determining which outpatient environment is right for that patient. A large part of that decision relates to the individual surgeon’s practice and can take many forms. For some surgeons, all of their cases are performed in the hospital. In that case, deeming a patient outpatient is just a matter of surgical boarding. Other surgeons with access to freestanding ASCs may routinely take all outpatients to those facilities. In our practice, we operate at a community hospital with a robust HOPD and an ASC in close proximity. Studies have shown that many of the patients who meet selection criteria for outpatient TJA are ultimately not discharged home on the day of surgery, reportedly as high as 21%. , As such, part of our decision-making process for surgical setting comes down to whether we believe that a patient is truly 100% willing and able to undergo an outpatient arthroplasty. If there is a possibility that the patient will need additional support prior to discharge, we board the patient in the HOPD as opposed to the ASC.
Our selection criteria include elements from scoring systems such as the OARA. However, we are not utilizing a specific system at this time. Patients are generally excluded if they have a BMI greater than 45, ASA score greater than 2, history of uncontrolled cardiovascular disease, uncontrolled diabetes mellitus or uncontrolled pulmonary disease, or end-stage renal disease. A comprehensive evaluation is performed on patients with a history of chronic opioid use. In these cases, an opioid record from the state is reviewed. Then, there is an independent discussion between the patient and our medical director (anesthesiology). Finally, there is a social and environmental screening that occurs to ensure that the patient has an appropriate home environment and support system.
When considering the transition to outpatient joint arthroplasty, one needs to critically evaluate the resources available and determine whether they are adequate to manage patients remotely. Historically, patients are seen in the hospital on postoperative days and have in-person interactions with the surgical team for evaluation, discussion, and to address any questions. While in the hospital, there are nurses and ancillary staff—including physical and occupational therapists, possibly internal medicine or hospitalists, case managers, and physician extenders—who interact with the patient and provide different insights throughout the hospital stay. With outpatient joint replacement, these interactions are limited to the span of hours instead of days. Therefore, it is necessary to adequately educate patients prior to discharge and to create a mechanism for patients to be followed remotely. Shah et al. described the burden of care for the surgical team and quantified the amount of time required for perioperative patient communication as an average of 48.4 minutes within 1 week of surgery. Interestingly, they report a trend toward longer-duration phone calls and more frequent incoming calls with same-day discharge versus next-day discharge patients. Extrapolate that time to all outpatient cases performed and it demonstrates the significant amount of resources required, many of which are not routinely embedded in clinical practice and processes.
In addition to appropriately selecting patients for outpatient arthroplasty, patients need preoperative education and expectation management regarding the planned discharge to home on the day of surgery. , , Preoperative patient education regarding pain management is also important for encouraging patient participation in nonmedication options for managing postoperative pain. Patient education can take the form of preoperative classes, educational handouts, web-based resources, or smartphone applications. We advocate for multiple educational avenues that send a consistent message to patients regarding the expectation for same-day discharge, the typical postoperative course, and the signs and symptoms that necessitate contacting the surgeon’s office and/or presenting to an ED. Patients should be informed regarding steps to follow when any postoperative concerns arise; this patient education should take place prior to the day of surgery. ,
Our initial educational process is standardized for all patients, whether inpatient or outpatient, and augmented for those who are ultimately boarded for outpatient surgery. We provide comprehensive educational materials that are reviewed with our surgical scheduler at the time surgery is scheduled. All patients are provided access to a mobile app with additional content and videos. A preoperative visit occurs 2 weeks prior to surgery with one of our physician extenders to review the material again. If the surgery is being performed at our ASC, the patients have the option (not mandatory) to attend a joint class at the facility or virtually and are given access to additional video content specific to the ASC. After surgery, all patients receive a phone call on postoperative days 1, 3, and 7, followed by a postoperative appointment 2 weeks after surgery. A change stemming from the COVID-19 pandemic is the availability of virtual preoperative and postoperative appointments, although the latter requires video access to visually inspect the wound and assess range of motion.
Intraoperative Complications—Perioperative Protocols
After appropriate patient selection, the establishment of institutional protocols is the next step in complication prevention. Protocols should be in place to standardize perioperative care and optimize safe same-day discharges. The following aspects of perioperative care are amenable to standard protocols that support successful outpatient arthroplasty: anesthesia, perioperative pain management, blood conservation measures, therapy, patient communication and the early recognition and treatment of adverse events occurring on the day of surgery or immediate postoperative period.
Whether inpatient or outpatient, what happens in surgery does not change for the most part. Surgical instrumentation, techniques, and implants are typically identical and what the surgeon does in the operating room (OR) should remain consistent. The processes surrounding the surgery itself may or may not change depending on the environment. It is essential for the surgeon and surgical team to have a comprehensive understanding of these differences in order to ensure patient safety with successful same-day discharge and to maintain high-quality outcomes. Outpatient surgery performed in the hospital or an associated HOPD will likely follow similar pathways in terms of equipment options, staffing, and processes that are available to surgeons performing inpatient joint arthroplasty. If the HOPD is not directly connected to the hospital, for the purpose of this chapter, it will have a similar environment to a freestanding ASC with similar, if not identical, limitations. As such, the final factor in appropriate patient selection is thorough review of the surgical case, templating for the necessary implants and anticipating the potential need for additional instrumentation, backup implants, or alternative equipment. ASCs typically have limited inventory; thus, anything that may not be routine would require coordination and appropriate inventory management. Cases that are more complex and might require atypical component sizes, augments, different levels of constraint, and the like, may be better suited in a hospital environment even if the patient ultimately goes home on the same day. Space, logistics, and inventory are important criteria to understand when selecting patients for the ASC. Even the typical size of the OR is different for each facility, as is the equipment (i.e., computers, monitors, booms, imaging, and so forth; Fig. 4.2 ).

Anesthesia and Pain Control
General, spinal, and regional anesthesia are all commonly used in TJA procedures and have been shown to be effective in outpatient arthroplasty. , , Spinal anesthesia has been found to be associated with fewer complications, reduced cost, and slightly reduced time in the OR. , Studies utilizing the American College of Surgeons national database have shown that general anesthesia is correlated with an increased likelihood of an inpatient stay or postoperative complication after both total hip and total knee arthroplasty. , The growing body of literature on the subject of single-dose spinal anesthesia for joint replacement is accompanied by an expanded discussion over which agents and dosages are most appropriate. , This is understandable given that the goal of anesthesia in an outpatient setting is to provide adequate anesthesia to perform the procedure with a timely return of motor function for rapid discharge while limiting potential complications. Four anesthetics in particular have been of interest: mepivacaine, bupivacaine, lidocaine, and chlorprocaine. , It can be difficult to interpret the results of these studies because the protocols and dosing vary significantly, which inevitably impacts the risks and benefits as well as overall functionality in an outpatient setting.
Bupivacaine has been widely used in the ambulatory setting due to its safety profile, but its potential for an effective duration of 3 to 9 hours could be prohibitive for same-day discharge. Yet, bupivacaine can be administered in various densities (i.e., isobaric and hyperbaric) with respect to the spinal fluid. Hyperbaric bupivacaine, because of its greater density, was found to have less cephalad distribution when administered in a seated position, faster onset of action, and shorter duration of sensory and motor blockade compared to other bupivacaine preparations. , Meta-analysis of isobaric versus hyperbaric bupivacaine found that the return of sensory and motor function for hyperbaric bupivacaine was 29.4 and 45.2 minutes, respectively. It is for this reason that hyperbaric bupivacaine is of interest in the outpatient setting. Lidocaine is an attractive option as well because it has a rapid onset and short duration of action. Traditionally, lidocaine has been associated with concerning side effects, such as transient neurologic symptoms (TNS) and has been largely abandoned. However, in more recent studies focusing on TJA, there was no evidence of development of TNS. , While hyperbaric bupivacaine spinal anesthesia has also been associated with TNS (3% in one series), its use in lieu of lidocaine is preferred at our institution for its safety profile. The potential risk of TNS with lidocaine is reported to be 7 times more likely when compared with other agents such as bupivacaine. Working closely with your anesthesiologist is important in finding the right anesthetic for you. It is important to consider a surgeon’s operative times and have realistic expectations when selecting the appropriate anesthetic agent.
Not all surgeons and anesthesiologists believe that spinal anesthesia is superior to general anesthesia. A recent single-center series of outpatient arthroplasty cases compares general anesthesia with single-dose bupivacaine spinal anesthesia. General anesthesia was associated with a lower incidence of postoperative urinary retention as well as increased ambulation distances in the recovery area. However, it is important to note that anesthesia type was not significantly associated with successful same-day discharge, and the data regarding postoperative ambulation may be confounded by the fact that all patients in this series received an indwelling femoral nerve catheter with ropivacaine for the duration of the procedure. Additionally, not all anesthesia is performed in isolation. There are several different options available to potentially augment general and spinal anesthesia with different types of regional blocks—including, for example, adductor canal blocks, fascia-iliaca block, and, less commonly, femoral nerve blocks. These can further be performed as a single shot or, in some cases, with a catheter for continuous postoperative analgesia.
Given the concerns with general anesthesia and aforementioned advantages of spinal anesthesia, we believe that there is an advantage to spinal anesthesia in an outpatient setting. Initially, we combined single-shot spinal anesthesia with adductor canal blocks for TKA and in isolation for THA. Recent evidence suggests that there are potential complications associated with continuous adductor canal blocks, as well as an increased cost associated with the use of these devices. Appropriate regional techniques require technical skill, with a failure rate ranging from 0% to 67%. Furthermore, there are reported complications specific to these regional blocks, including motor weakness in up to 76%, which can result in decreased ambulation and prolonged return to quadriceps function or, worse yet, potential for postoperative fall. Cadaveric studies have demonstrated that the spread of local infiltration into the adductor canal is technique dependent, and there may be migration that could affect the efficacy of the block and clinically impact the benefits. As a result, we have shifted away from adductor canal blocks altogether and now use low-dose, single-shot hyperbaric bupivacaine spinal anesthesia for all of our outpatient joint procedures. Intraoperatively, we also perform local periarticular injections, which have been shown to reduce postoperative pain and opioid consumption. ,
Finally, the use of a multimodal pain protocol is recommended for all TJA procedures. The goal of multimodal management is to shift away from opioid-based, reactive pain treatment and proactively utilize nonnarcotic medications that target nonopioid pharmacologic pathways. Rather than treating patients’ pain at onset, the proactive multimodal approach begins to target pain ahead of any surgical intervention through the use of a combination of agents that act on various pain pathways. The American Association of Hip and Knee Surgeons recently released clinical practice guidelines advocating for multimodal analgesia regimens. These multimodal strategies include a combination of preemptive analgesia, neuraxial perioperative anesthesia, peripheral nerve blocks, periarticular injections, and multimodal oral opioid and nonopioid medications that span the entire perioperative period. Several studies have demonstrated the benefits of these strategies, which are effective for improving discharge and post-discharge analgesia. ,
Additional Considerations for an Ambulatory Surgery Center
Whether in the hospital or affiliated HOPD, there are a number of resources available that as surgeons we may often take for granted. While the rate of blood transfusions in TJA is low, blood products and perhaps different resuscitation fluids may not be on hand. Blood conservation protocols with routine tranexamic acid administration are recommended to minimize blood loss and postoperative anemia. Physical and occupational therapy are often involved in predischarge evaluation in these facilities even if patients are scheduled as outpatients. Some advocate that patients should be evaluated by a physical therapist to ensure that the patient can safely mobilize and appropriately use the prescribed assistive device. , , Depending on the arrangements that each ASC has with therapists, these evaluations may or may not be an option prior to discharge. In our ASC, we do not contract with physical therapy; we have educated and trained our postanesthesia care unit (PACU) nursing staff to perform those duties for our patients. Most ASCs do not have a dedicated physical therapy area and use the recovery space instead ( Fig. 4.3 ). Regardless of which model is being used, make sure that the therapists or nurses understand your protocols, are equipped to educate the patients, and are prepared to assist them with any prescribed assistive devices.

Postoperative Complications
Managing Immediate Issues
Common events that may delay or prevent same-day discharge can be addressed with institutional protocols to minimize their impact on successful discharge. These events include postoperative nausea and vomiting, hypotension, hypertension, urinary retention, and oversedation. , , , , Although less common, surgical and anesthesia staff must be prepared to manage serious adverse events such as malignant hyperthermia, transient neurologic symptoms, acute cardiac events, and anemia requiring blood transfusion. , The anesthesiology team is expected to manage these issues, but we recommend discussing the protocols with your anesthesiologists in advance, especially if you are new to the ASC or if your ASC recently started doing TJA. This ensures that both you and the anesthesia group, including certified registered nurse anesthetists (CRNAs), are comfortable managing these rare events and that there is an appropriate process in place to ensure patient safety. The utility of protocols to ensure patient safety is especially important if a patient’s condition necessitates transfer to an increased level of care. Although uncommon, an ASC needs a mechanism in place to provide emergent transportation to the appropriate inpatient facility. This highlights an important difference when planning outpatient surgery at a freestanding ASC versus a HOPD. Whereas a patient can be readily transferred from an HOPD to an inpatient care unit or ED, ASCs require protocols in place for emergency medical services and transfer of care.
In addition to medical complications requiring unplanned care, intraoperative complications require the availability of resources not typically anticipated. For instance, a vascular injury may require hemostatic agents or other stabilizing measures pending vascular surgery consultation. A periprosthetic fracture may require cable-cerclage systems and revision implants that would otherwise go unused at an ASC. Remember that an ASC typically only stocks what they are asked to stock in inventory. If you are doing a TKA and there is an iatrogenic injury to a collateral ligament, do you have the right suture available for primary repair or the correct brace to supply postoperatively? Others may treat the same injury by changing to a more constrained implant, but is that implant and instrumentation available? Or if you do a hip replacement with a Charnley retractor and it is dropped on the floor, is there a backup instrument or tray available? If not, what is the sterile processing capacity of the facility? The central processing department at a freestanding surgical center does not have the same capacity as that of a hospital; therefore, surgeons must have mechanisms in place to ensure the appropriate availability of all necessary equipment ( Fig. 4.4 ). Another common concern is instrument contamination. We all agree that it should not happen, but even in the best facilities it does at times. The general principles for successful outpatient arthroplasty at an ASC include understanding the limitations of the facility in which you operate, knowing what you absolutely need or do not need to perform a given case, ensuring that there is a system in place to accommodate your patient if something unexpected happens, and making sure that the entire team is aware of these protocols and prepared to act to remedy situations as they arrive.

Finally, despite optimal patient selection and perioperative management, it is possible that a patient will not meet discharge criteria from the ASC on the day of surgery. There should be an option for 23-hour observation when necessary ( Fig. 4.5 ). In some facilities, there are dedicated rooms and staff to accommodate this, but not every ASC has the same resources available. It is important to know what options your facility has should a patient need an overnight stay to ensure a safe discharge and to educate your patients and staff appropriately.

Managing the Patient After Discharge
An essential component to successful outpatient arthroplasty is the patient’s social support at home. If the patient does not have a family member or friend willing and able to facilitate the transition from the surgery center to home, then same-day discharge may not succeed despite otherwise optimal patient selection and perioperative protocols. Therefore, education of the appropriate caregiver is essential to the same-day discharge process. ,
The education process continues after discharge between the patient and caregiver in the early postoperative time period. This communication should occur proactively—contacting patients to inquire regarding the patient’s recovery—and in response to any concerns or questions that the patient may have. Routinely calling patients on postoperative day 1 is common practice at the our institution and elsewhere. Giving patients the ability to contact office staff with any questions or concerns as they arise may increase the administrative burden, but it can also prevent unnecessary ED visits and readmissions.
Early Postoperative Complications: Prevalence and Management
Comparative studies suggest that complication rates are similar after outpatient and inpatient arthroplasty. Moreover, the limited data available suggest similar complication rates between outpatient arthroplasty performed at an ASC versus a HOPD in appropriately selected patients. The single randomized controlled trial comparing outpatient versus inpatient arthroplasty found no difference between groups in terms of postoperative complications, readmissions, reoperations, or Harris Hip Scores. Retrospective studies comparing the complication rates between inpatient and outpatient arthroplasty range from single-surgeon, matched-cohort analyses to national database studies that include all total joint patients, with an outpatient cohort representing <1% of the total. , The latter offer larger sample sizes and greater statistical power but lack granularity in assessing orthopaedic-specific complications. For instance, a reoperation for superficial wound dehiscence may be grouped together with a revision of all components for acute prosthetic joint infection. The former allow for more detailed comparisons of matched cohorts at the cost of limited sample size, which may be underpowered to detect true differences. However, when pooling the data from comparative studies that do not rely on national databases, complication rates remain similar between groups ( Table 4.1 ).
