Inpatient vs Outpatient Total Knee Replacement

Osteoarthritis (OA) is a leading cause of disability and reduced quality of life, presenting a substantial, growing burden to patients and the healthcare system (1). Total knee arthroplasty (TKA) is an established, effective interventions for advanced OA. The prevalence of knee OA is rapidly increasing, resulting in a rising demand for care. The number of procedures is expected to grow by 48%, by 2020 in the US (2). Currently, TKA along with total hip arthroplasty (THA), have a significant impact on healthcare budgets, costing approximately $1.2 billion in annual spending in Canada (3). These staggering numbers highlight the critical need to improve care delivery.

A significant proportion of the overall cost of joint replacement results from the inpatient hospital stay following the procedure. Historically, the standard procedure following TKA required an inpatient hospital stay of two and a half to three weeks, however the introduction of less invasive surgical techniques, improved medical and analgesia management and comprehensive rehabilitation have enabled shorter inpatient stays. Today, the median inpatient stay following TKA is three days in Canada (3). A desire for greater autonomy by the patients as well as patients wanting early mobilization to accelerate recovery and return to activities has led some clinicians to consider an outpatient arthroplasty program. The proposed benefits of outpatient arthroplasty include similar patient outcomes with significantly lower hospital costs, and improved patient satisfaction, independence, and autonomy, however there is a lack of high-quality evidence comparing clinical outcomes of outpatient to inpatient arthroplasty models of care.

A retrospective analysis of over 50,000 THA and TKA procedures found no differences in 30-day major complications or readmissions among patients with a zero to two-day hospital stay compared to those discharged on day three or four postoperative (4). Small cohort studies (5-8) suggest lower costs for outpatients and improved patient satisfaction but have inherent biases; limited to carefully selected patients in privatized health systems.

It is estimated that up to 20% of the overall cost of joint replacement can be attributed to the inpatient stay in hospital at our institution (9). By discharging patients as outpatients, it could be possible to save 20% of the overall costs of joint replacement. Although these preliminary calculations are encouraging, it is not sufficient to effect change solely to achieve cost control, without consideration of safety, effectiveness and patient satisfaction. Further, it is unknown whether the financial savings will be outweighed by additional postoperative costs, increased readmissions or decreased quality of care. A full economic evaluation that simultaneously evaluates cost and effectiveness is crucial prior to implementation. The lack of high-quality evidence regarding its effectiveness warrants a rigorous comparative trial.

The purpose of this study is to evaluate outpatient care pathways for TKA. Specifically, our objectives are to compare the rate of serious adverse events and estimate the cost-effectiveness of outpatient compared to standard inpatient TKA.

Inclusion criteria

• Osteoarthritis of the knee
• Booked for primary unilateral total knee arthroplasty
• Have the ability to read and understand English (printed instructions are provided in English only)
• Home / cell phone access
• Planning to be discharged to home environment
• Patient has an adult to accompany them home post-operatively

Exclusion criteria

• Cognitive issues that preclude the ability to understand instructions or provide informed consent
• Lack of a social supports at home
• American Society of Anaesthesiologists (ASA) score equal to or less than 4