Does Operative Time Modify Obesity-related Outcomes in THA?
Maveric K I L Abella1,2, John P M Angeles1,3, Andrea K Finlay1
1Stanford University Department of Orthopaedic Surgery, Stanford, CA, USA.
Clinical Orthopaedics and Related Research
|April 21, 2023
Summary
Operative time, not just obesity, significantly impacts total hip arthroplasty (THA) outcomes. Addressing longer surgical times is crucial for improving THA safety and accessibility for obese patients.
Area of Science:
- Orthopaedic Surgery
- Biostatistics
- Public Health
Background:
- Orthopaedic surgeons often deny total hip arthroplasty (THA) to morbidly obese patients due to higher complication rates.
- Existing recommendations overlook the impact of increased operative time on obesity-related THA outcomes like readmission and reoperation.
- Accounting for operative time is essential for accurately assessing surgical risk in obese patients undergoing THA.
Purpose of the Study:
- To determine if the increased risk in overweight and obese patients undergoing THA is associated with longer operative times.
- To investigate if increased operative time, independent of body mass index (BMI) class, is a risk factor for adverse outcomes.
- To analyze whether operative time modifies the association between obesity and adverse THA outcomes.
Main Methods:
- Retrospective analysis of 235,061 elective THA cases from the National Surgical Quality Improvement Project (NSQIP) database (2014-2020).
- Patients were categorized by BMI (underweight to Class III obesity); multivariable logistic regression adjusted for demographic and comorbidity factors.
- Analyses were repeated adjusting for operative time, with an interaction model to assess time's effect on BMI-related outcomes.
Main Results:
- Adjusting for operative time significantly reduced the increased odds of readmission, reoperation, and complications previously attributed to Class III obesity.
- Each 15-minute increase in operative time independently raised the odds of readmission (7%), reoperation (10%), and complications (10%).
- A significant interaction effect between operative time and BMI indicated that longer surgeries exacerbate the risks for readmission and reoperation in obese patients.
Conclusions:
- Operative time is a significant factor, potentially acting as a proxy for surgical complexity, contributing to adverse outcomes in THA patients.
- Modulating risks associated with lengthened operative times, through surgical techniques and training, is key to improving THA accessibility and safety.
- Future THA outcome studies should incorporate operative time to better understand obesity's independent effects and promote equitable patient access.
