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. Cite this article:
