The recognition of hips at risk of displacement
in children with cerebral palsy (CP) is a difficult problem for
the orthopaedic surgeon. The Gross Motor Function Classification
System (GMFCS) and head–shaft angle (HSA) are prognostic factors
for hip displacement. However, reference values for HSA are lacking.
This study describes and compares the development of HSA in normal
hips and children with CP. We selected 33 children from a retrospective cohort with unilateral
developmental dysplasia of the hip (DDH) (five boys, 28 girls) and
50 children (35 boys, 15 girls) with CP with GMFCS levels II to
V. HSA of normal developing hips was measured at the contralateral
hip of unilateral DDH children (33 hips) and HSA of CP children
was measured in both hips (100 hips). Measurements were taken from
the radiographs of the children at age two, four and seven years.
The normal hip HSA decreased by 2° per year (p <
0.001). In children
with CP with GMFCS levels II and III HSA decreased by 0.6° (p =
0.046) and 0.9° (p = 0.049) per year, respectively. The HSA did
not alter significantly in GMFCS levels IV and V. Between the ages of two and eight years, the HSA decreases in
normal hips and CP children with GMFCS level, II to III but does
not change in GMFCS levels IV to V. As HSA has a prognostic value
for hip displacement, these reference values may help the orthopaedic
surgeon to predict future hip displacement in children with CP. Cite this article:
