title: The gothic arch: a reliable measurement for developmental dysplasia of the hip.
abstract: BACKGROUND
  The "Gothic Arch" is a radio-graphic finding on AP pelvis x-rays postulated to be predictive of hip osteoarthritis.
  
  
  OBJECTIVE
  The purpose of this study was to determine the reliability of measurement of the Gothic Arch in patients with no known hip pathology and patients with unilateral developmental dysplasia of the hip (DDH).
  
  
  METHODS
  After obtaining IRB approval, nine skeletally mature patients (18 hips) with no known hip pathology were selected to serve as the control group. The AP pelvis x-rays at skeletal maturity of eight patients (16 hips) with unilateral DDH treated with closed reduction and casting comprised the comparison group. A digitizing program was designed to measure the Gothic Arch based on landmarks identified by the user. Two pediatric orthopaedic surgeons and two orthopaedic residents completed the program on two separate occasions. Intra-and interobserver reliability were determined using intraclass cor-relation coefficients (ICC) for continuous variables.
  
  
  RESULTS
  Both the unilateral DDH group and the control group demonstrated excellent inter- and intraobserver reliability (ICC >0.70) for base, height, area, and orientation of the Gothic Arch, but poor reliability (ICC <0.40) for medial and lateral sharpness.
  
  
  CONCLUSIONS
  The Gothic Arch can be reliably measured on AP pelvis x-rays of patients with normal and dysplastic hips.
  
  
  METHODS
  III, Diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.
authors.forename: Paul K
authors.initials: PK
authors.lastname: Herickhoff
authors.forename: Megan K
authors.initials: MK
authors.lastname: O'Brien
authors.forename: Lori A
authors.initials: LA
authors.lastname: Dolan
authors.forename: Jose A
authors.initials: JA
authors.lastname: Morcuende
authors.forename: Jonathan B
authors.initials: JB
authors.lastname: Peterson
authors.forename: Stuart L
authors.initials: SL
authors.lastname: Weinstein
mesh_terms: D005260:Female; D006617:Hip Dislocation / Q000000981:diagnostic imaging*; D006618:Hip Dislocation, Congenital / Q000000981:diagnostic imaging*; D006621:Hip Joint / Q000473:pathology*; D006801:Humans; D008297:Male; D015207:Osteoarthritis, Hip / Q000000981:diagnostic imaging*; D010384:Pelvic Bones / Q000000981:diagnostic imaging*; D011859:Radiography
references.citation: Clin Orthop Relat Res. 2011 Jan;469(1):188-99
references.pmid: 20596806
references.citation: Clin Orthop Relat Res. 1983 May;(175):79-85
references.pmid: 6839611
references.citation: Clin Orthop Relat Res. 1986 Dec;(213):20-33
references.pmid: 3780093
references.citation: Clin Orthop Relat Res. 2009 Mar;467(3):666-75
references.pmid: 19048356
references.citation: Acta Orthop Belg. 2001 Oct;67(4):374-9
references.pmid: 11725570
references.citation: J Pediatr Orthop B. 2001 Oct;10(4):293-7
references.pmid: 11727371
references.citation: Bull Hosp Jt Dis. 1996;54(4):215-21
references.pmid: 8731413
references.citation: Clin Orthop Relat Res. 2003 Feb;(407):241-8
references.pmid: 12567152
references.citation: J Pediatr Orthop. 2004 Mar-Apr;24(2):156-60
references.pmid: 15076599
references.citation: Rheumatology (Oxford). 2005 Feb;44(2):211-8
references.pmid: 15479751
references.citation: J Bone Joint Surg Br. 1979 Aug;61-B(3):334-8
references.pmid: 158025
references.citation: Br J Radiol. 1965 Nov;38(455):810-24
references.pmid: 5842578
references.citation: J Bone Joint Surg Am. 1994 Dec;76(12):1777-92
references.pmid: 7989383