Is Combined Anteversion Equally Affected by Acetabular Cup and Femoral Stem Anteversion? |
| |
Authors: | Aidin Eslam Pour Ran Schwarzkopf Kunj Pareshkumar Patel Manan Anjaria Jean Yves Lazennec Lawrence D Dorr |
| |
Institution: | 1. Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, MI;2. Department of Orthopaedic Surgery, New York University, New York, NY;3. Department of Orthopaedic and Trauma Surgery, Pitié-Salpétrière Hospital Assistance Publique–Hopitaux de Paris, UPMC, Paris, France;4. Dorr Institute for Arthritis Research and Education, Los Angeles, CA |
| |
Abstract: | BackgroundTo create a safe zone, an understanding of the combined femoral and acetabular mating during hip motion is required. We investigated the position of the femoral head inside the acetabular liner during simulated hip motion. We hypothesized that cup and stem anteversions do not equally affect hip motion and combined hip anteversion.MethodsHip implant motion was simulated in standing, sitting, sit-to-stand, bending forward, squatting, and pivoting positions using the MATLAB software. A line passing through the center of the stem neck and the center of the prosthetic head exits at the polar axis (PA) of the prosthetic head. When the prosthetic head and liner are parallel, the PA faces the center of the liner (PA position = 0, 0). By simulating hip motion in 1-degree increments, the maximum distance of the PA from the liner center and the direction of its movement were measured (polar coordination system).ResultsThe effect of modifying cup and stem anteversion on the direction and distance of the PA’s change inside the acetabular liner was different. Stem anteversion influenced the PA position inside the liner more than cup anteversion during sitting, sit-to-stand, squatting, and bending forward (P = .0001). This effect was evident even when comparing stems with different neck angles (P = .0001).ConclusionCup anteversion, stem anteversion, and stem neck-shaft angle affected the PA position inside the liner and combined anteversion in different ways. Thus, focusing on cup orientation alone when assessing hip motion during different daily activities is inadequate. |
| |
Keywords: | total hip arthroplasty combined anteversion acetabular implant anteversion femoral stem anteversion hip-spine relation sagittal pelvic tilt |
本文献已被 ScienceDirect 等数据库收录! |
|