A Prospective, Randomized Study of Surgical Positioning Software Shows Improved Cup Placement in Total Hip Arthroplasty.

Several technologies are available to assist surgeons with acetabular component positioning in total hip arthroplasty. The purpose of this study was to determine whether surgical positioning software would improve cup position compared with fluoroscopy. This prospective, randomized study compared 200 primary total hip arthroplasty cups placed with and without surgical positioning software. All cases were performed by a single surgeon using the direct anterior approach with fluoroscopy. The target abduction and anteversion angles were set at 40 degrees and 20 degrees, respectively, and measured postoperatively. Cup placement time, total fluoroscopy time, and cup position were compared between groups. Mean abduction was 40.4 degrees (range, 32.7 degrees-49.0 degrees) in the software group compared with 42.3 degrees (range, 33.7 degrees-51.1 degrees) in the control group. The cups placed using software were significantly closer to the target abduction angle (P<.001) with fewer outliers. Mean anteversion was 20.8 degrees (range, 11.2 degrees-31.7 degrees) in the software group compared with 21.8 degrees (range, 11.3 degrees-34.3 degrees) in the control group (P=.063). Eighty-seven percent of cups in the software group fell within 5 degrees of the abduction target, compared with only 68% in the control group (P<.01). Cup placement took longer in the software group (7: 04 minutes vs 4: 58 minutes, P<. 001), and 2 seconds more total fluoroscopy time was used in that group as well (12.9 seconds vs 11.1 seconds, P<. 001). The software improved both the accuracy and the precision of cup placement, with only modest increases in surgical time and fluoroscopy time.