Predictors for Unfavorable Early Outcomes in Elective Total Hip Arthroplasty: Does Extreme Body Mass Index Matter?
Chun-Yu Hung1, Chih-Hsiang Chang1,2, Yu-Chih Lin1,2
1Department of Orthopaedic Surgery, Chang Gung Memorial Hospital, Linkou, Taiwan.
Insights
Body Mass Index (BMI) alone is not a risk factor for 30-day complications after total hip arthroplasty (THA). Advanced age and cardiovascular comorbidities are independent risk factors for increased complications.
Area of Science:
- Orthopedic Surgery
- Arthroplasty Research
- Patient Outcomes
Background:
- Controversial associations exist between extreme Body Mass Index (BMI) and complication rates after total hip arthroplasty (THA).
- Previous cohort studies have yielded conflicting results regarding BMI and THA outcomes.
- Understanding BMI's role in perioperative complications is crucial for patient management.
Purpose of the Study:
- To compare 30-day perioperative complications across different BMI categories in patients undergoing primary THA.
- To investigate the association between BMI and key surgical outcomes including operative time, blood loss, and length of stay.
- To identify independent risk factors for 30-day complications following THA.
Main Methods:
- A retrospective cohort study of 1565 patients undergoing unilateral primary THA between 2010 and 2015.
- Patients were categorized into underweight, normal-weight, overweight, class I obesity, and morbidly obese groups based on BMI.
- Assessment of 30-day complications, operative time, blood loss, and hospital length of stay.
Main Results:
- Morbidly obese patients exhibited higher complication rates (8.9% vs. 2.4%), longer operative times, and greater blood loss compared to normal-weight patients.
- Underweight patients showed no 30-day complications, with no significant differences compared to normal-weight patients.
- Multivariate analysis indicated that higher BMI was not an independent risk factor for 30-day complications; advanced age and cardiovascular comorbidities were significant independent risk factors.
Conclusions:
- While morbidly obese patients experienced increased operative time, blood loss, and complications, BMI itself is not an independent predictor of 30-day complications after THA.
- Clinicians should counsel elderly patients, especially those with cardiovascular comorbidities, about potential increased risks.
- Total hip arthroplasty should not be withheld solely based on a patient's BMI.
Background:
Studies of previous cohorts have demonstrated a controversial association between extreme body mass index (BMI) and complication rates following total hip arthroplasty (THA). The purpose of this study was to compare 30-day perioperative complications in underweight (BMI <18.50 kg/m2), normal-weight (BMI 18.50-24.99 kg/m2), overweight (BMI 25.00-29.99 kg/m2), class I obesity (BMI 30.00-34.99 kg/m2), and morbidly obese (BMI ≥35.00 kg/m2) groups.
Methods:
We performed a cohort study including patients who underwent unilateral primary THA by a single surgeon between January 2010 and December 2015 at our institution. We assessed 30-day complications, operation time, operative blood loss, and length of hospital stay.
Results:
We identified 1565 primary THAs that were performed in patients with varying BMI levels. Compared with the normal-weight patients, the morbidly obese group had a higher 30-day complication rate (8.9% vs. 2.4%), longer operative time (79 minutes vs. 70 minutes), and more blood loss (376 mL vs. 302 mL). Underweight patients did not present any 30-day complications, and there were no differences among underweight and normal-weight patients regarding complication rates, operative time, or blood loss. The mean length of hospital stay was comparable among the different BMI groups. In the multivariate regression model, higher BMI was not associated with a higher risk of 30-day complications. Independent risk factors for 30-day complications were advanced age, prolonged operative time, and cardiovascular comorbidities.
Conclusion:
Although increased operative time, blood loss, and perioperative complications were seen in the morbidly obese patients, BMI alone was not an independent risk factor for a higher 30-day complication rate. Therefore, our data suggest clinicians should make elderly patients aware of increased 30-day complications before the procedure, particularly those with cardiovascular comorbidities. Withholding THA solely on the basis of BMI is not justified.
