Outpatient Total Hip Arthroplasty, Total Knee Arthroplasty, and Unicompartmental Knee Arthroplasty
Authors: Pollock Michael , Somerville Lyndsay , Firth Andrew , Lanting Brent 
Published: January 2017

Background:
The demand for total hip arthroplasty (THA), total knee arthroplasty (TKA), and unicompartmental knee arthroplasty (UKA) is growing rapidly because of the proven success of these procedures and an increase in the aging population. However, resources are limited and health-care budgets are finite. Recently, a number of care providers have started performing these procedures on an outpatient basis, with the patients being discharged from the hospital on the day of surgery. The primary objective of this systematic review was to examine the evidence regarding the safety and feasibility of performing THA, TKA, or UKA on an outpatient basis.

Methods:
An electronic search of 3 online databases (Embase, MEDLINE, and HealthSTAR) was conducted to identify eligible studies. The reference lists of identified articles were then screened. All studies evaluating outcomes following outpatient THA, TKA, or UKA were included. Eligible articles that included a comparative group were assessed for methodological quality with use of the Cochrane Risk of Bias Assessment Tool for Non-Randomized Studies of Interventions (ACROBAT-NRSI). Non-comparative studies were assessed for quality with use of the Effective Public Health Practice Project (EPHPP) Quality Assessment Instrument.

Results:
The electronic literature search yielded 805 articles. Following a review of the titles, abstracts and reference lists, 26 articles remained and were assessed for eligibility. Of those, 17 articles (≈79,500 patients) met the inclusion criteria and were included in the review. Although both quality-assessment tools showed that the majority of studies included in the review were of poor quality, there was no increase in readmission rates or perioperative complications among patients who underwent outpatient procedures. Studies assessing satisfaction illustrated a high level of satisfaction for the majority of patients. The average age of the patients in the THA studies ranged from 53.5 to 63 years. The TKA and UKA studies included an older population, with mean ages ranging from 55 to 68 years. The majority of the included studies included a larger percentage of males as compared with females. Of the 17 included studies, 4 were cohort studies with a control group and 13 were case series. All 4 cohort studies indicated that the complication rates and clinical outcomes were similar between the inpatient and outpatient groups. Furthermore, the 3 studies that involved an economic analysis indicated that outpatient arthroplasty is financially advantageous.

Conclusions:
In selected patients, outpatient THA, TKA, and UKA can be performed safely and effectively. The included studies lacked sufficient internal validity, sample size, methodological consistency, and standardization of protocols and outcomes. There is a need for high-quality prospective cohort and randomized trials to definitively assess the safety and effectiveness of outpatient THA, TKA, and UKA.

Level of Evidence:
Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.