title: Relationship between pelvic incidence and osteoarthritis of the hip.
abstract: OBJECTIVE
  Sagittal alignment of the lumbosacral spine, and specifically pelvic incidence (PI), has been implicated in the development of spine pathology, but generally ignored with regards to diseases of the hip. We aimed to determine if increased PI is correlated with higher rates of hip osteoarthritis (HOA). The effect of PI on the development of knee osteoarthritis (KOA) was used as a negative control.
  
  
  METHODS
  We studied 400 well-preserved cadaveric skeletons ranging from 50 to 79 years of age at death. Each specimen's OA of the hip and knee were graded using a previously described method. PI was measured from standardised lateral photographs of reconstructed pelvises. Multiple regression analysis was performed to determine the relationship between age and PI with HOA and KOA.
  
  
  RESULTS
  The mean age was 60.2 years (standard deviation (sd) 8.1), and the mean PI was 46.7° (sd 10.7°). Multiple regression analysis demonstrated a significant correlation between increased PI and HOA (standardised beta = 0.103, p = 0.017). There was no correlation between PI and KOA (standardised beta = 0.003, p = 0.912).
  
  
  CONCLUSIONS
  Higher PI in the younger individual may contribute to the development of HOA in later life.Cite this article: Dr J. J. Gebhart. Relationship between pelvic incidence and osteoarthritis of the hip. Bone Joint Res 2016;5:66-72. DOI: 10.1302/2046-3758.52.2000552.
authors.affiliation: Department of Orthopaedic Surgery, University Hospitals Case Medical Center, 11100 Euclid Avenue, Cleveland, OH 44106, USA jjg112@case.edu.
authors.forename: J J
authors.initials: JJ
authors.lastname: Gebhart
authors.affiliation: Department of Orthopaedic Surgery, University Hospitals Case Medical Center, 11100 Euclid Avenue, Cleveland, OH 44106, USA.
authors.forename: D S
authors.initials: DS
authors.lastname: Weinberg
authors.affiliation: Warren Alpert Medical School of Brown University, 222 Richmond Street, Providence, RI 02903, USA.
authors.forename: M S
authors.initials: MS
authors.lastname: Bohl
authors.affiliation: Department of Orthopaedic Surgery, Rainbow Babies and Children's Hospital, 11100 Euclid Avenue, RBC 6081, Cleveland, OH 44106, USA.
authors.forename: R W
authors.initials: RW
authors.lastname: Liu
keywords: hip; osteoarthritis; pelvic incidence; sagittal balance; spine