The Learning Curve From Converting From Fluoroscopic to Robotic-Assisted Direct Anterior Total Hip Arthroplasty.

Abstract

Robotic-assisted total hip arthroplasty (RA-THA) provides an alternative to fluoroscopic guidance, thus reducing radiation exposure for orthopaedic surgeons. This study was performed to assess the learning curve associated with the adoption of RA-THA using the direct anterior approach (DAA) with regard to surgical time, use of fluoroscopy, and implant placement. In addition, we compared complication rates and patient-reported outcome scores between both cohorts. A case report of an RA-THA is also presented. This was a retrospective, non-randomized evaluation of the learning curve by assessing surgical time on a consecutive series of 89 DAA cases performed by a single surgeon. There were 53 cases that had manual THA with fluoroscopy and 36 cases with RA-THA. All cases had an acetabular component placement target of 40° inclination and 20° anteversion. An independent reviewer blinded to surgical technique used the Widmer method to measure acetabular inclination and version. Patient demographics were similar for both groups. The mean surgical time for the manual fluoroscopic group was 88 ± 21 minutes and 101 ± 14 minutes for the RA-THA group. After 15 RA-THA cases, surgical time reached time neutral compared to the manual fluoroscopic group. The first 17 RA-THA cases utilized fluoroscopy to verify implant position until the surgeon became comfortable with the accuracy of the RA-THA system. After case 17, fluoroscopy was abandoned in all subsequent RA-THA cases. The mean radiation dose delivered to the surgical field was 5.61 ± 5.71 mGy. Manual THA with fluoroscopy resulted in a mean acetabular inclination of 41.3 ± 4.4° and a mean anteversion of 22.4 ± 3.0°. The RA-THA resulted in a mean acetabular inclination of 42.0 ± 4.2° and a mean anteversion of 22.3 ± 3.9°. There was no noted change in RA-THA placement accuracy after case 17, when fluoroscopy was eliminated from the surgical workflow. There were no statistical differences between the manual fluoroscopic and robotic-assisted groups with respect to complications and clinical PROM outcomes. The DAA THA can be performed with RA-THA and achieve comparable acetabular placement without fluoroscopy. Surgical time was higher for the RA-THA group during the learning curve, but then decreased and was consistent with the manual fluoroscopic group after 15 cases.