Jean Y Lazennec1, Frederic Thauront1, Christopher B Robbins2, Aidin E Pour2. 1. Department of Orthopaedic and Trauma Surgery, Pitié-Salpêtrière Hospital Assistance Publique-Hôpitaux de Paris, UPMC, Paris, France. 2. Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, Michigan.
Abstract
BACKGROUND: Although most hip dislocations occur in either standing or sitting position, the safe zone for implant position is defined for the supine position. Our goal was to determine preoperative and postoperative pelvis and hip orientations and whether the safe zone defined in supine position can be used to assess standing radiographs. METHODS: Preoperative and postoperative three-dimensional EOS images were assessed in 66 total hip arthroplasty patients. None of the patients had dislocation within the follow-up period (12-36 months). The acetabular anteversion (both anterior pelvic plane [APP] and patient functional plane) and the femoral anteversion were measured. The sacral slope, pelvic version, pelvic inclination, and pelvic incidence were also measured. RESULTS: Acetabular anteversion increased postoperatively in both APP and patient functional plane (P <.001). Femoral neck anteversion decreased postoperatively (P =.0942). Sacral slope was 42.4° (-25.9° to 24°) preoperatively compared with 40.3° (-4.1° to 64.2°) postoperatively (P =.013). Pelvic version changed from 15.2° (-10.4° to 43.8°) to 17.2° (-6° to 46.7°; P = 0.008). Pelvic inclination was 1.12° (-25.9° to 24°) before total hip arthroplasty and -1.2° (-40.7° to 23.4°) postoperatively (P =.005). CONCLUSION: The acetabular and femoral implant orientations in standing position reside out of the safe zone in most patients. The APP is not vertical in standing position in most patients due to anterior or posterior pelvic tilt. The proposed safe zone in supine position may not be a useful measure in the assessment of standing radiographs of patients with significant anterior or posterior pelvic tilt. LEVEL OF EVIDENCE: Level IV, therapeutic case series study.
BACKGROUND: Although most hip dislocations occur in either standing or sitting position, the safe zone for implant position is defined for the supine position. Our goal was to determine preoperative and postoperative pelvis and hip orientations and whether the safe zone defined in supine position can be used to assess standing radiographs. METHODS: Preoperative and postoperative three-dimensional EOS images were assessed in 66 total hip arthroplastypatients. None of the patients had dislocation within the follow-up period (12-36 months). The acetabular anteversion (both anterior pelvic plane [APP] and patient functional plane) and the femoral anteversion were measured. The sacral slope, pelvic version, pelvic inclination, and pelvic incidence were also measured. RESULTS: Acetabular anteversion increased postoperatively in both APP and patient functional plane (P <.001). Femoral neck anteversion decreased postoperatively (P =.0942). Sacral slope was 42.4° (-25.9° to 24°) preoperatively compared with 40.3° (-4.1° to 64.2°) postoperatively (P =.013). Pelvic version changed from 15.2° (-10.4° to 43.8°) to 17.2° (-6° to 46.7°; P = 0.008). Pelvic inclination was 1.12° (-25.9° to 24°) before total hip arthroplasty and -1.2° (-40.7° to 23.4°) postoperatively (P =.005). CONCLUSION: The acetabular and femoral implant orientations in standing position reside out of the safe zone in most patients. The APP is not vertical in standing position in most patients due to anterior or posterior pelvic tilt. The proposed safe zone in supine position may not be a useful measure in the assessment of standing radiographs of patients with significant anterior or posterior pelvic tilt. LEVEL OF EVIDENCE: Level IV, therapeutic case series study.
Authors: Joost H J van Erp; Thom E Snijders; Harrie Weinans; René M Castelein; Tom P C Schlösser; Arthur de Gast Journal: Arch Orthop Trauma Surg Date: 2021-06-08 Impact factor: 2.928
Authors: Bernard H van Duren; Joseph M Royeca; Conor M Cunningham; Jonathan N Lamb; Chris J Brew; Hemant Pandit Journal: Hip Int Date: 2020-08-04 Impact factor: 2.135
Authors: Aidin Eslam Pour; Ran Schwarzkopf; Kunj Paresh Kumar Patel; Manan P Anjaria; Jean Yves Lazennec; Lawrence D Dorr Journal: J Orthop Res Date: 2021-03-22 Impact factor: 3.102