Orthopedic aspects of the Marfan phenotype.

: Thirty-six patients with the phenotypic features of Marfan's syndrome (arachnodactyly, abnormal ratio of arm span to height, ligamentous laxity, and tall stature) were evaluated and classified into three groups. Group 1 represented definite Marfan's syndrome and included patients with two or more major signs, with additional minor signs as described by McKusick (18 patients). Group 2 represented probable Marfan's syndrome and included patients with one major sign and multiple minor signs (nine patients). Group 3 represented the Marfan phenotype and included patients with multiple minor signs (nine patients). A high incidence of scoliosis occurred in all groups (100% in Group 1 and 89% in Groups 2 and 3 combined). Group 1 patients had longer, multiple, and more progressive spinal curves. Protrusio acetabuli (Type II and III hips) was present in 22 patients (11 in Group 1, six in Group 2, and five in Group 3), with more severe involvement noted in Group 1. Foot deformities of varying types and severity occurred in all groups but were seen most often in Group 1 patients. Patients with the features of Marfan's syndrome (even without major diagnostic criteria) have a high incidence of progressive scoliosis, protrusio acetabuli, and foot deformities.