Intraoperative Fluoroscopic Grid in Total Hip Arthroplasty in Supine Position: Improving Cup Position, Leg Length and Hip Offset

Abstract

Introduction: Accurate placement of implants is important to prevent a variety of complications including dislocation, decreased range of motion, and premature polyethylene wear in Total Hip Arthroplasty (THA). In addition, the difference in leg length after THA affects postoperative gait and low back pain, and the femoral offset is related to gait and abductor muscle function. The purpose of this study is to investigate whether implant placement, leg length difference, and hip offset are improved in supine THA using a 9-inch fluoroscopic HipGrid Drone. Materials and Methods: We retrospectively reviewed consecutive 80 patients who underwent primary unilateral primary THA through direct anterior approach at supine position: 40 THAs with the use of fluoroscopy and 9-inch Drone, and 40 THAs with the use of fluoroscopy alone. We compared the accuracy of component positioning, leg length discrepancy, and hip offset with or without Drone. Results: There was no significant difference in the inclination angle of the cup between the Drone group 37.9 degrees and the control group 39.0 degrees (p=0.175), but the variation from the target angle was more less in the Drone group compared with the control group (2.37 vs 3.82 degrees, p=0.013). With the use of the Drone, significantly more THAs had restoration of