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° 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°, compared with an average of 43.4° 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.