Author: Arnaldo Valedon, M.D.
ASA Monitor 02 2018, Vol.82, 16-17.
Total joint replacement surgery has undergone significant evolution in the last 20 years. In the year 2000, the average hospital length of stay for these procedures was four to five days with a transition to skilled nursing facility or rehabilitation floor ranging from five days to three weeks. With improvement in surgical techniques (i.e., minimally invasive approach), pain management techniques and appropriate patient selection, patients are routinely discharged from the hospital on postoperative day one or two.
Fast forward to 2017. A rapidly increasing number of patients undergoing total joint replacements are being routinely discharged three to 23 hours post-procedure with equal or lesser complication and re-admission rates to patients with longer discharge times. By the year 2025, SG2 Health Care & Hospital System Consultancy predicts that approximately 15 percent of all primary hip total replacements and 20 percent of all primary knee replacements will be performed on an outpatient basis.
The continued growth of outpatient total joint surgery has been affected by three main factors: appropriate patient selection, social readiness and financial considerations. Evidence from a variety of sources reveal that age over 80, ASA Physical Status ≥ 3, body mass index > 40 kg/m2, blood dyscrasias and use of anticoagulation therapy, tobacco abuse, pre-exisiting physical disabilities, malnutrition, and uncontrolled diabetes are specifically linked to worse outcomes in patients undergoing outpatient total joint replacements. Also, as with any other surgical procedures, baseline comorbid conditions need to be optimized.
Social readiness factors are also essential components for successful outpatient total joint replacement, and this starts with an educated and motivated patient who has a positive psychological outlook about the surgery. The patient should be functionally independent or have a caregiver who will be able to assist at home post-discharge. The patient must make a commitment to actively participate in pre-procedure rehabilitation sessions as well as a post-procedure rehabilitation program. Of note, patients who start rehabilitation exercises pre-procedure have been shown to have better outcomes and quicker recovery than patients who do not.
The continued migration of total joint replacements to the outpatient environment has also had positive financial implications. Medicare payment for hip or knee total joint replacement was estimated to be more than $50,000 per case in 2014. It is estimated that Medicare paid more than $7 billion for the 400,000 Medicare beneficiaries who received hip or knee total replacements. In 2016, private health plans were estimated to have paid $26,000-$44,000 per total knee and hip replacements nationally. By doing these procedures on an outpatient basis, the cost can be reduced by at least 20-30 percent. There is an active proposal being submitted to the Centers for Medicare & Medicaid Services (CMS) by several national organizations regarding changing the existing rule preventing payment for total joint replacements on an outpatient basis for Medicare beneficiaries. How such potential change will affect Medicare’s bundled-payment initiative for inpatient total joint replacements (i.e., the Comprehensive Care for Joint Replacement Model) remains to be seen. However, the cost savings for outpatient total joint replacements are factual and have been calculated both short and long term for patients.
Successful perioperative anesthetic management of patients undergoing outpatient total joint replacements hinges on a multimodal approach. The overarching goals in order to achieve early postoperative rehabilitation (frequently while the patient is in PACU) include zero to minimal PONV, well-controlled pain and zero to minimal motor blockade to allow very early mobility.
Protocols described in the literature include the use of preoperative administration of acetaminophen, celecoxib, gabapentinoid/pregabalin, dexamethasone and oxycodone. Preoperative regional blocks may include a combination of saphenous/adductor canal blocks (ADB) and infiltration on the interspace between the popliteal artery and the capsule of the posterior knee (IPACK) for total knee replacements. Fascia iliaca blocks have also been used for total hip replacements. Interscalene blocks have been used for total shoulder replacements, with the understanding that motor blockade might delay early postoperative rehabilitation.
Anesthetic management for outpatient total hip/knee replacements include spinal or general anesthetics with an array of pros and cons. Factors such as whether a patient is scheduled for a 23-hour/overnight stay versus not and desired elapsed time in recovery before a patient starts postoperative rehabilitation clearly affect the choice of anesthetic(s) (e.g., immediately after patient is mentating well and can ambulate effectively versus a more delayed start within the 23-hour postoperative period). Successful protocols for outpatient total shoulder replacement include general anesthesia or brachial plexus block either as single injections or continuous infusions with sedation. Again, the preference by the surgical service for how quickly postoperative rehabilitation is to start will influence the choice of anesthesia and adjuvant therapy. Postoperative protocols described for the management of total joint replacements are typically multimodal as well. These include the use acetaminophen, celecoxib, gabapentin/pregabalin and oral opioids.
Over the last five years, clinical outcome studies are increasing, as are the number of patients included in them. These studies have shown that outpatient replacement does not increase the risk of re-admission or re-operation within 30-days postoperatively. The complication rates with respect to infection as well as major morbidity and mortality have been similar between inpatient and outpatient total joint replacements. Of note, a small cohort of patients in one study showed an increased risk of postoperative transfusions in outpatient total knee patients.
More data are certainly warranted in the this area, but appropriate patient selection as well as evolving surgical techniques and multimodal techniques for pain management will continue to be major factors for the successful management of patients undergoing outpatient total joint replacement.