Protrusio acetabuli in Marfan's syndrome.

In an unselected series of 14 patients with Marfan's syndrome, protrusio acetabuli was documented by both presence of a center edge (CE) angle of 40 degrees or more and crossing of the teardrop by the femoral head. The disorder was unilateral in 8 patients, bilateral in 6. Since most of the CE angles were measured on scoliosis roentgenograms, the measurements were made in a control group with an average CE angle of 33.1 degree, compared with an average of 43.4 degree in the Marfan's group. One of the hips with protrusio was associated with chondrolysis. Protrusio acetabuli is a common abnormality of persons with Marfan's syndrome. It may be related to the same mesenchymal tissue disorder that predisposes these persons to scoliosis, chest wall deformities, and other skeletal malformations.