title: Spinopelvic mobility and acetabular component position for total hip arthroplasty.
abstract: OBJECTIVE
  Posterior tilt of the pelvis with sitting provides biological acetabular opening. Our goal was to study the post-operative interaction of skeletal mobility and sagittal acetabular component position.
  
  
  METHODS
  This was a radiographic study of 160 hips (151 patients) who prospectively had lateral spinopelvic hip radiographs for skeletal and implant measurements. Intra-operative acetabular component position was determined according to the pre-operative spinal mobility. Sagittal implant measurements of ante-inclination and sacral acetabular angle were used as surrogate measurements for the risk of impingement, and intra-operative acetabular component angles were compared with these.
  
  
  RESULTS
  Post-operatively, ante-inclination and sacral acetabular angles were within normal range in 133 hips (83.1%). A total of seven hips (4.4%) had pathological imbalance and were biologically or surgically fused hips. In all, 23 of 24 hips had pre-operative dangerous spinal imbalance corrected.
  
  
  CONCLUSIONS
  In all, 145 of 160 hips (90%) were considered safe from impingement. Patients with highest risk are those with biological or surgical spinal fusion; patients with dangerous spinal imbalance can be safe with correct acetabular component position. The clinical relevance of the study is that it correlates acetabular component position to spinal pelvic mobility which provides guidelines for total hip arthroplasty. Cite this article: Bone Joint J 2017;99-B(1 Supple A):37-45.
authors.affiliation: Keck Medical Centre of USC, 1520 San Pablo Street, Suite 2000, Los Angeles, CA 90033, USA.
authors.forename: M
authors.initials: M
authors.lastname: Stefl
authors.affiliation: Keck Medical Centre of USC, 1520 San Pablo Street, Suite 2000, Los Angeles, CA 90033, USA.
authors.forename: W
authors.initials: W
authors.lastname: Lundergan
authors.affiliation: Keck Medical Centre of USC, 1520 San Pablo Street, Suite 2000, Los Angeles, CA 90033, USA.
authors.forename: N
authors.initials: N
authors.lastname: Heckmann
authors.affiliation: Keck Medical Centre of USC, 1520 San Pablo Street, Suite 2000, Los Angeles, CA 90033, USA.
authors.forename: B
authors.initials: B
authors.lastname: McKnight
authors.affiliation: Keck Medical Centre of USC, 1520 San Pablo Street, Suite 2000, Los Angeles, CA 90033, USA.
authors.forename: H
authors.initials: H
authors.lastname: Ike
authors.affiliation: Keck Medical Centre of USC, 1520 San Pablo Street, Suite 2000, Los Angeles, CA 90033, USA.
authors.forename: R
authors.initials: R
authors.lastname: Murgai
authors.affiliation: Keck Medical Centre of USC, 1520 San Pablo Street, Suite 2000, Los Angeles, CA 90033, USA.
authors.forename: L D
authors.initials: LD
authors.lastname: Dorr
mesh_terms: D000077:Acetabulum / Q000000981:diagnostic imaging / Q000601:surgery*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects / Q000379:methods*; D005260:Female; D057925:Femoracetabular Impingement / Q000000981:diagnostic imaging / Q000209:etiology; D005500:Follow-Up Studies; D006621:Hip Joint / Q000000981:diagnostic imaging; D006622:Hip Prosthesis; D006801:Humans; D007593:Joint Instability / Q000150:complications* / Q000000981:diagnostic imaging; D007738:Kyphosis / Q000150:complications; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011859:Radiography; D012307:Risk Factors; D013123:Spinal Fusion / Q000009:adverse effects
keywords: Arthroplasty