Quality and Safety Research

The studies featured here present recent findings about patient safety and quality of care in the ASC setting. Please see the full text for each study to review the methodology and conclusions in greater detail.

Research Highlights

Outpatient THA Performed at an ASC vs Hospital Outpatient Setting: Complications, Revisions, and Readmissions

The Journal of Arthroplasty

Published: July 2019

Finding: Authors examined 3000+ total hip arthroplasty (THA) procedures performed by two surgeons from 2013 to 2018, specifically looking at differences in the demographics and outcomes for cases in ASCs vs. HOPDs. They found no difference in 90-day complication rate, revision rate, reoperation rate, emergency department visits, or readmission rates between the two populations. Authors conclude that THA can be safely performed in ASCs.

Returns to specialization: Evidence from the outpatient surgery market

Journal of Health Economics

Published: January 2018

Finding: Patients experienced a reduction in adverse events following surgery in ASCs relative to HOPDs for the 10 most common procedures (by ASC volume). A reduction in post-procedure adverse events was observed for both low- and high-risk patients.

Additional Studies

Click on the tabs below to see research on each topic. Within each section studies are ordered from most to least recently published.

Site of Service Outcomes Comparisons

Analysis of operating room efficiency between a hospital-owned ambulatory surgical center and hospital outpatient department

American Journal of Surgery

Published: April 2019

Finding: Authors reviewed procedures in an ASC vs. HOPD, specifically looking at components of total case time during surgery to examine operating room efficiency. Of the 220 procedures examined, they found better turnover time, less ancillary time, shorter procedure time, earlier exit times, and less nonoperative time, concluding that outpatient procedures in the ASC are more efficient than those performed in the HOPD.

Outcomes of Surgeries Performed in Physician Offices Compared With Ambulatory Surgery Centers and Hospital Outpatient Departments in Florida

Health Services Insights

Published: April 2017

Finding: Examining a sample of 88 outpatient procedures using a 2008–2012 private claims insurance database, researchers found significantly higher 7- and 30-day hospital admission rates following procedures in HOPDs vs. ASCs and physician offices.

7-day risk adjusted readmission | ASC: 0.82%, PO: 1.57%, HOPD: 1.71%

30-day risk adjusted readmission | ASC: 2.03%, PO: 2.72%, HOPD: 2.98%

Prevalence of Malignant Hyperthermia Diagnosis in New York State Ambulatory Surgery Center Discharge Records 2002 to 2011

Anesthesia & Analgesia

Published: February 2016

Finding: Looked at New York State ambulatory surgery discharge records 2002–2011 for ICD-9-CM code 995.86 (indicates malignant hyperthermia due to anesthesia). Rate of MH found to be 0.18 per 100,000 discharges, less than hospital rate (1 per 100,000) and national rate (1.3 per 100,000).

ASC Cost and Price Effects

Competition in Outpatient Procedure Markets

Medical Care

Published: January 2019

Finding: ASC availability was associated with decreases in overall outpatient procedure prices, mostly due to reductions in the prices paid to hospital outpatient departments. Results suggest that competition from ASCs benefits consumers through lower prices for outpatient procedures.

Outpatient Total Hysterectomy in the Freestanding ASC Setting – Experience With 819 Consecutive Cases

The Journal of Minimally Invasive Gynecology

Published: November 2017

Finding: Authors looked at outcomes for a large series of total hysterectomies performed between 2010 and 2017, with cost implications in mind. They found that minimally invasive hysterectomy in am ASC is feasible and reproducible, with an average cost roughly $5,000 less than performance in a HOPD.

Orthopedic Procedures

Transition to outpatient total hip and knee arthroplasty: experience at an academic tertiary care center

Arthroplasty Today

Published: November 2018

Finding: Retrospective review of 105 patients who underwent outpatient THA or TKA following an outpatient protocol compared to inpatients from the same time period. Outpatient readmission and complication rates (0.95%, 1.9%) were better than inpatient rates (3.7%, 2.9%). Authors conclude that Outpatient THA and TKA in a well-selected patient is feasible in an academic multidisciplinary tertiary care hospital, with complication rates approximating inpatient surgery. The findings reported can be used to further optimize outpatient arthroplasty protocols.

Inpatient Versus Outpatient Hip and Knee Arthroplasty: Which Has Higher Patient Satisfaction?

The Journal of Arthroplasty

Published: July 2018

Finding: Although satisfaction was high in both outpatient and inpatient groups, when differences were present, patients favored outpatient surgery in the ambulatory surgery center.

Is Outpatient Unicompartmental Knee Arthroplasty Safe to Perform at an Ambulatory Surgery Center? A Comparative Study of Early Post-Operative Complications

The Journal of Arthroplasty

Published: March 2018

Finding: A review of 569 outpatient unicompartmental knee arthroplasties performed 2012 to 2016 (288 ASC, 281 HOPD) revealed no difference in overall complication rate between the two settings.

Quality of Recovery, Postdischarge Hospital Utilization, and 2-Year Functional Outcomes After an Outpatient Total Knee Arthroplasty Program

The Journal of Arthroplasty

Published: February 2018

Finding: Authors compared 43 inpatients and 43 outpatient TKAs between 2010 and 2015 by a single surgeon. Patients were given a diary to complete at post-discharge intervals, and study tracked 90-day complications, readmissions, and ED visits. Outpatient TKA in selected patients produced similar short-term and 2-year patient-reported outcome measures and a comparable 90-day post-discharge hospital resource utilization when compared to an inpatient cohort, supporting further investigation into outpatient TKA.

Safety of Outpatient Shoulder Surgery at a Freestanding Ambulatory Surgery Center in Patients Aged 65 Years and Older: A Review of 640 Cases

Journal of the American Academy of Orthopaedic Surgeons

Published: January 2018

Finding: Our findings are consistent with currently reported outpatient hospital-based data and illustrate the safety of outpatient shoulder procedures at a freestanding ambulatory surgery center in Medicare-age patients.

The outpatient total hip arthroplasty: a paradigm change

The Bone and Joint Journal

Published: January 2018

Finding: Authors reviewed 1,472 total hip arthroplasties (THAs) performed at an ASC between 2013 and 2016. They found a low complication rate (2.2%) despite the fact that 44% of the patients observed had one or more major comorbidities. Based on this, they conclude that in their population comorbidities was not associated with medical or surgical complications and that outpatient THA is safe for a large proportion of patients without the need for a standardized risk assessment score.

Hand Surgery in the Ambulatory Surgery Center

Orthopedic Clinics

Published: January 2018

Finding: 65% of hand surgeons report doing most of their surgery at an ASC, and in 2006, 49% of carpal tunnel release procedures were done in ASCs (up from 16% in 1996). Use of ASCs for hand surgery is more cost-effective and efficient than an inpatient facility, with a low (0.2%–2.5%) complication rate.

Outpatient total shoulder arthroplasty in an ambulatory surgery center is a safe alternative to inpatient total shoulder arthroplasty in a hospital: a matched cohort study

The Journal of Shoulder and Elbow Surgery

Published: January 2017

Finding: Comparing two samples (30 patients matched for age/comorbidity) of patients undergoing total shoulder arthroplasty at an ASC and an inpatient hospital, there was no significant difference in 90-day episode-of-care complication rates such as hospital admission/readmission.

The Safety of Hand and Upper-Extremity Surgical Procedures at a Freestanding Ambulatory Surgery Center: A Review of 28,737 Cases

The Journal of Bone and Joint Surgery

Published: April 2016

Finding: A retrospective review of 28,000+ cases found an overall low (0.20%) rate of adverse events (defined as serious complications leading to patient harm or additional treatment).

Spine Proedures

Comparison of Transforaminal Lumbar Interbody Fusion in the Ambulatory Surgery Center and Traditional Hospital Settings, Part 2: Assessment of Surgical Safety in Medicare Beneficiaries

Journal of Personalized Medicine

Published: March 2023

Finding: Minimally invasive TLIF can be performed safely and efficiently in the ASC in Medicare-age patients.

Outpatient and Inpatient Single-level Cervical Total Disc Replacement: A Comparison of 30-day Outcomes


Published: January 2019

Finding: There was no difference between 30-day complications, readmission, and reoperation rates between inpatients and outpatients who underwent a single-level cervical TDR. Furthermore, the overall 30-day complication rates were low. This study supports that single-level cervical TDR can be performed safely in an outpatient setting.

Safety and Efficiency of Cervical Disc Arthroplasty in Ambulatory Surgery Centers vs. Hospital Settings

International Journal of Spine Surgery

Published: October 2018

Finding: Authors compared a sample of ASC patients, hospital outpatients, and hospital inpatients undergoing cervical disc arthroplasty (CDA). They find that surgeries in ASCs are of shorter duration and performed with less blood loss, concluding that both 1- and 2-level CDAs may be performed safely in ASCs.

Outpatient Spine Clinic Utilization is Associated With Reduced Emergency Department Visits Following Spine Surgery.


Published: July 2018

Finding: Authors examined TRICARE (military) claims from 2006 to 2014 for three common spine procedures. The primary outcome assessed was emergency department (ED) utilization at 30- and 90-days post procedure (roughly 50k patients met selection criteria). They found that use of outpatient spine clinic services was the only factor independently associated with significant reduction in likelihood of ED utilization at 30- and 90-days.

Spine Surgery in the Ambulatory Surgery Center Setting: Value-Based Advancement or Safety Liability?


Published: March 2018

Finding: Following a comprehensive review of clinical studies of cervical and lumbar surgeries in ASCs available at the time, the authors conclude that evidence for the safety and utility of multiple outpatient spine procedures is growing and providers, payers, hospitals and patients all stand to benefit if greater investments are made in ASCs for spine surgery.

Outpatient vs Inpatient Anterior Cervical Discectomy and Fusion: A Population-Level Analysis of Outcomes and Cost


Published: May 2017

Finding: Authors examined 3000+ ambulatory and 46,000+ inpatient elective anterior cervical discectomy and fusions (ACDFs) performed in CA, FL, and NY from 2009 to 2011. They found higher 30-day emergency room visits, and higher readmission/reoperation rates for the inpatient population. Overall charges were significantly lower in ambulatory settings ($33,362) than inpatient settings ($74,667).

GI Procedures

Long-term Risk of Colorectal Cancer and Related Deaths After a Colonoscopy With Normal Findings

JAMA Internal Medicine

Published: December 2018

Finding: A negative colonoscopy result in average-risk patients was associated with a lower risk of colorectal cancer and related deaths for more than 12 years after examination, compared with unscreened patients. Our study findings may be able to inform guidelines for rescreening after a negative colonoscopy result and future studies to evaluate the costs and benefits of earlier vs later rescreening intervals.

For inquiries regarding ASC research please contact Alex Taira, ASCA's Regulatory Policy and Research Manager at ataira@ascassociation.org.