Protrusio acetabuli in Marfan's syndrome

Marfan's syndrome is an autosomal dominant disorder of connective tissue, c ommonly involving the cardiovascular, ocular, and skeletal systems. Revised criteria for the clinical diagnosis of Marfan's syndrome regard skeletal i nvolvement as a major criterion if at least four of eight typical skeletal manifestations are present, one of which is protrusio acetabuli, Using Kulm an's method to determine the presence of protrusio, we analysed the pelvic X-rays of 15 patients with Marfan's syndrome and 15 controls, Protrusio was present in 47% (7/15) of Marfan patients, compared with 7% (1/15) of contr ols (P = 0.035). Using the revised criteria, the presence of protrusio woul d have affected the final diagnosis of Marfan's syndrome in only one patien t out of 15, Therefore, we recommend that a pelvic X-ray is reserved for th ose cases in which the presence of protrusio will alter the final diagnosis , With regard to the radiological assessment of protrusio, in our opinion t his can be performed simply and reliably using the position of the acetabul ar line alone.