Radiographic diagnosis of hemophilic osteoarthropathy.

Presently, the degree of the hemophilic arthropathy is estimated by the classification system of Pettersson, which is recommended by the Orthopedic Advisory Committee of the World Federation of Hemophilia. This classification system bases upon plain radiographs of the joints and analyses only those changes which represent the progression of the arthropathy. The value of this classification system has been established by interobserver studies. However, it shows drawbacks at the exact definition of some parameters. Presently, it is more valuable for longitudinal than for transversal studies. Due to the possibilities of an adequate substitution therapy, only minor degrees of an arthropathy are observed in children. The ankle joints are more severly affected than the elbow joints and they more than the knee joints. This distribution is explained by an increasing sports activity in children. If more than 3 joint bleedings occur within a year the invent of an arthropathy must be presumed. Because the classification system of Pettersson analyses only osseous changes representing late changes, important early changes like hypertrophy of the synovialis and focal destruction of the joint cartilage are overlooked. Magnetic resonance imaging is suitable to show these early changes reliably. MRI can be recommended for the investigation of recurrently bleeding joints without evidence of major osseous changes and for decision making to perform a synovectomy.