title: The radiological assessment of pelvic obliquity in cerebral palsy and the impact on hip development.
abstract: Pelvic obliquity is a common finding in adolescents with cerebral palsy, however, there is little agreement on its measurement or relationship with hip development at different gross motor function classification system (GMFCS) levels. The purpose of this investigation was to study these issues in a large, population-based cohort of adolescents with cerebral palsy at transition into adult services. The cohort were a subset of a three year birth cohort (n = 98, 65M: 33F, with a mean age of 18.8 years (14.8 to 23.63) at their last radiological review) with the common features of a migration percentage greater than 30% and a history of adductor release surgery. Different radiological methods of measuring pelvic obliquity were investigated in 40 patients and the angle between the acetabular tear drops (ITDL) and the horizontal reference frame of the radiograph was found to be reliable, with good face validity. This was selected for further study in all 98 patients. The median pelvic obliquity was 4° (interquartile range 2° to 8°). There was a strong correlation between hip morphology and the presence of pelvic obliquity (effect of ITDL on Sharpe's angle in the higher hip; rho 7.20 (5% confidence interval 5.59 to 8.81, p < 0.001). This was particularly true in non-ambulant adolescents (GMFCS IV and V) with severe pelvic obliquity, but was also easily detectable and clinically relevant in ambulant adolescents with mild pelvic obliquity. The identification of pelvic obliquity and its management deserves closer scrutiny in children and adolescents with cerebral palsy.
authors.affiliation: University Children's Hospital Zurich, Steinwiesstrasse 75, Zurich, 8032, Switzerland.
authors.forename: C
authors.initials: C
authors.lastname: Heidt
authors.affiliation: University of Hamburg, Turmweg 2, 20148 Hamburg, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Hollander
authors.affiliation: The Royal Children's Hospital, 50 Flemington Road, Parkville, Victoria 3052, Australia.
authors.forename: J
authors.initials: J
authors.lastname: Wawrzuta
authors.affiliation: Murdoch Children's Research Institute, 50 Flemington Road, Parkville, Victoria 3052, Australia.
authors.forename: C
authors.initials: C
authors.lastname: Molesworth
authors.affiliation: The Royal Children's Hospital, 50 Flemington Road, Parkville, Victoria 3052, Australia.
authors.forename: K
authors.initials: K
authors.lastname: Willoughby
authors.affiliation: The Royal Children's Hospital, 50 Flemington Road, Parkville, Victoria 3052, Australia.
authors.forename: P
authors.initials: P
authors.lastname: Thomason
authors.affiliation: The Royal Children's Hospital, 50 Flemington Road, Parkville, Victoria 3052, Australia.
authors.forename: A
authors.initials: A
authors.lastname: Khot
authors.affiliation: The Royal Children's Hospital, 50 Flemington Road, Parkville, Victoria 3052, Australia.
authors.forename: H K
authors.initials: HK
authors.lastname: Graham
mesh_terms: D000293:Adolescent; D002547:Cerebral Palsy / Q000000981:diagnostic imaging*; D005260:Female; D006615:Hip / Q000254:growth & development* / Q000473:pathology; D006801:Humans; D008297:Male; D010388:Pelvis / Q000000981:diagnostic imaging*; D011859:Radiography; D055815:Young Adult
keywords: GMFCS; adolescent; cerebral palsy; dislocation; hip; pelvic obliquity