INACCURACY OF THE MIGRATION PERCENTAGE AND CENTER-EDGE ANGLE IN PREDICTING FEMORAL-HEAD DISPLACEMENT IN CEREBRAL-PALSY

Six patients (seven hips) with total-body-involvement cerebral palsy w ere assessed for a hip reconstruction, Four patients (five hips) under went three-dimensional computerized tomographic (3D CT) scans, and in two patients, faux profile views were obtained. The femoral head was s ubluxed or dislocated anteriorly in all seven hips. The migration perc entage (MP) and center-edge angle (CEA) underestimated the pathology. We conclude that the MP and CEA do not exclude an anterior displacemen t of the femoral head and calls into question the accuracy of methods relying on two-dimensional imaging in assessing hip containment in thi s group of patients. The faux profile view is sufficient to show an an terior hip displacement but a 3D CT gives superior detail to help in p lanning a surgical reconstruction.