Does Approach Matter in Robotic-Assisted Total Hip Arthroplasty? A Comparison of Early Reoperations Between Direct Anterior and Postero-Lateral Approach

Background There is no consensus on whether direct anterior approach (DAA) or postero-lateral approach (PLA) total hip arthroplasty (THA) confers a lower risk of postoperative complications. Robotic assistance in THA results in a more consistently accurate component position compared to manual THA. The objective of this study was to compare rates of dislocation, re-operation, revision, and patient-reported outcome measures (PROMs) between patients undergoing DAA and PLA robotic-assisted primary THA. Methods We identified 2,040 consecutive robotic-assisted primary THAs performed for primary osteoarthritis, utilizing DAA (n = 497) or PLA (n = 1,542) between 2017 and 2020. The mean follow-up was 18 months. Kaplan-Meier analysis estimated survivorship free of dislocation, re-operation, and revision. Achievement of patient acceptable symptom state (PASS) and minimum clinically important difference (MCID) were used to compare changes in the Hip Disability and Osteoarthritis Outcome Score, Joint Replacement (HOOS JR), and Visual Analogue Scale (VAS). Results Dislocation was rare in this series (14 in 2,040, 0.7%), including 1 of 497 (0.2%) in the DAA cohort and 13 of 1,542 (0.8%) in the PLA cohort (P = 0.210). There was no difference in 2-year re-operation-free survivorship (97.8 versus 98.6%, P = 0.59) or revision-free survivorship (98.8 versus 99.0%, P = 0.87) at any timepoint. After controlling for age, sex, and body mass index, there was no difference in dislocation, re-operation, or revision. At 6-week follow-up, after controlling for age, sex, and BMI, patients in the DAA cohort had higher odds of achieving HOOS JR MCID (OR [Odds Ratio] = 2.01, P = 0.012) and HOOS JR PASS (OR = 1.72, P = 0.028). There were no differences in PROMs by 3 months. Conclusion For robotic-assisted primary THA, DAA may confer enhanced early (<6 weeks) functional recovery compared to the PLA, but there was no significant difference in postoperative dislocation, re-operation, or revision rates.