title: Acetabular component navigation in lateral decubitus based on EOS imaging: A preliminary study of 13 cases.
abstract: BACKGROUND
  Acetabular component navigation classically requires palpation of the bone landmarks defining the anterior pelvic plane (APP) (anterior superior iliac spine [ASIS] and pubis), the recording of which is not very reliable when performed in lateral decubitus. The objectives of the current experimental study were: (1) to assess the clinical feasibility of NAVEOS navigation (based on EOS imaging) in lateral decubitus; and (2) to compare precision versus classical APP-based navigation (NAVAPP).
  
  
  OBJECTIVE
  Iliac plane navigation using EOS is as reliable as APP navigation.
  
  
  METHODS
  A continuous prospective series of 13 total hip replacements were implanted in lateral decubitus under APP-guided navigation (NAVAPP). Planning used preoperative EOS measurement. The ASIS, pubis and ipsilateral posterior superior iliac spine (PSIS) were located and exported to the navigator. Intra-operatively, NAVEOS landmarks (acetabular center, ASIS and PSIS on the operated side) were palpated. Postoperatively, cup inclination and anteversion with respect to the APP were measured on EOS imaging (SterEOS3D software). The SterEOS3D measurements were compared to those of the performed NAVAPP and simulated NAVEOS navigations.
  
  
  RESULTS
  Three patients were excluded for technical reasons. In the remaining 10, inclination on NAVAPP and SterEOS3D differed by a median 4° (range, 0-12°), and on NAVEOS versus SteEOS3D by 5° (range, 2-10°); anteversion on NAVAPP and SterEOS3D differed by a median 4.5° (range, 0-12°), and on NAVEOS versus SteEOS3D by 4° (range, 0-14°).
  
  
  CONCLUSIONS
  Precision was comparable between NAVEOS and classical navigation. NAVEOS simplifies cup navigation in lateral decubitus on initial acquisition. These results require validation on a larger sample.
authors.affiliation: Pôle d'orthopédie, hôpital Pellegrin, CHU de Bordeaux, place Amélie-Raba-Léon, 33000 Bordeaux, France. Electronic address: anselme75@gmail.com.
authors.forename: A
authors.initials: A
authors.lastname: Billaud
authors.affiliation: Pôle d'orthopédie, hôpital Pellegrin, CHU de Bordeaux, place Amélie-Raba-Léon, 33000 Bordeaux, France.
authors.forename: N
authors.initials: N
authors.lastname: Verdier
authors.affiliation: Pôle d'orthopédie, hôpital Pellegrin, CHU de Bordeaux, place Amélie-Raba-Léon, 33000 Bordeaux, France.
authors.forename: R
authors.initials: R
authors.lastname: de Bartolo
authors.affiliation: Pôle d'orthopédie, hôpital Pellegrin, CHU de Bordeaux, place Amélie-Raba-Léon, 33000 Bordeaux, France.
authors.forename: N
authors.initials: N
authors.lastname: Lavoinne
authors.affiliation: Pôle d'orthopédie, hôpital Pellegrin, CHU de Bordeaux, place Amélie-Raba-Léon, 33000 Bordeaux, France.
authors.forename: D
authors.initials: D
authors.lastname: Chauveaux
authors.affiliation: Pôle d'orthopédie, hôpital Pellegrin, CHU de Bordeaux, place Amélie-Raba-Léon, 33000 Bordeaux, France.
authors.forename: T
authors.initials: T
authors.lastname: Fabre
mesh_terms: D000077:Acetabulum / Q000000981:diagnostic imaging* / Q000601:surgery*; D000368:Aged; D059925:Anatomic Landmarks; D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D005260:Female; D006622:Hip Prosthesis; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D056888:Patient Positioning; D011446:Prospective Studies; D011630:Pubic Bone; D011859:Radiography; D025321:Surgery, Computer-Assisted / Q000379:methods*
keywords: Arthroplasty; Cup anteversion; Cup inclination; EOS; Hip; Navigation