In-Hospital Complications and Costs of Simultaneous Bilateral Total Hip Arthroplasty: The Case for Selection and Potential Cost Savings.

Background: Published comparisons between bilateral and unilateral total hip arthroplasty (THA) remain controversial regarding the potential risks and benefits. Our objectives were to compare (1) postoperative complications and (2) resource utilization of patients having simultaneous bilateral THA with patients having unilateral procedures.

Methods: The Nationwide Inpatient Sample was used to identify patients undergoing primary elective THA from January 2016 to December 2019. Complications and costs were compared between unilateral and simultaneous bilateral patients. Binary logistic regression analysis controlling demographics, comorbidities, and the primary diagnosis was performed to compare the cohorts of unilateral and bilateral patients.

Results: Nine thousand nine hundred fifty-five Bilateral procedures and 785,609 unilateral procedures were identified. Patients with bilateral procedures were at increased risk for many medical complications including gastrointestinal complications (OR: 4.1; 95% CI: 2.4-6.9, < .01), postoperative blood transfusions (OR: 3.6; 95% CI: 3.3-3.9, < .01), and pulmonary embolisms (OR: 3.2; 95% CI: 2.0-5.1, < .01). Patients with bilateral procedures were also at increased risk for joint complications, including periprosthetic fractures (OR: 7.4; 95% CI: 5.2-10.5, < .01) and other mechanical complications (OR: 27.0; 95% CI: 23-30, < .01). These patients also incurred higher index hospitalization costs ($25,347 vs $16,757, < .001) and were discharged more commonly to a rehabilitation facility (17.8% vs 13.4%, < .001).

Conclusions: Bilateral THA are at increased risk of developing postoperative complications despite being younger and having fewer comorbidities on average when compared with unilateral patients. While bilateral patients had a higher index hospitalization cost, the overall cost of one episode of care is lower than two separate hospitalizations.