Capsular change following Chiari innominate osteotomy.

The case of a child treated at the age of 23 months for congenital dislocation of the hip by Chiari innominate osteotomy is presented. When additional surgery was required at the age of 4 years, exploration was made of the acetabulum which had been formed 2 years earlier by the Chiari procedure. Histologic evaluation revealed that capsular changes in the tissue interposed between the femoral head and the new acetabulum had produced well-vascularized, connective tissue with abundant collagen. The nature of the change in this tissue helps to explain why Chiari medial displacement innominate osteotomy may be successful.