- Hemophilia is a defect in coagulation by a deficiency clotting factor or clotting that is nonfunctional.
- Deficiencies of factor VIII (antihemophilic factor) lead to classic hemophilia (hemophilia A), and deficiencies offactor IX (plasma prothromboplastin component) lead to Christmas disease (hemophilia B).
- These genetic disorders are X-Iinked recessive. They primarily affect males, but are transmitted by females.
- The clinical and radiologic features of patients with classic hemophilia and Christmas disease are virtually identical.
- Hemorrhage most often occurs in the synovial joints. In descending order, the knee, ankle, elbow, shoulder, and hip are involved.
- Repetitive bleeding into the musculoskeletal system is the most common complication of both conditions.
- Bleeding into the joints leads to hemophilic arthropathy.
- Bleeding into muscles causes joint contractures
- Bleeding into bone and adjacent soft tissues results in osseous and soft-tissue pseudotumors.
 Imaging Findings
 Hemophilic arthropathy
- Findings vary greatly with the different stages of hemophilic arthropathy (acute, subacute, or chronic hemarthrosis)
- Reflect the presence of hemarthrosis (joint effusion), synovial inflammation and hyperemia (osteoporosis and epiphyseal overgrowth), chondral erosions and subchondral resorption (osseous erosions and cysts), cartilaginous denudation (joint space narrowing), intraosseous or subperiosteal hemorrhage (pseudotumors), and osseous proliferation (sclerosis and osteophytes).
- Some abnormalities of osseous shape, such as widening of the intercondylar notch, flattening of the condylar surface, or squaring of the patella, are very characteristic of chronic hemarthrosis of the knee.
Patient #1: Hemophilic arthropathy involving the bilateral knees
Patient #2: Bleeding into Kidney
Patient #3: Radiographs and MRI from a patient with hemophilia
 See Also
 External Links
- Hermann, G, Gilbert, MS, Abdelwahab, IF Hemophilia: evaluation of musculoskeletal involvement with CT, sonography, and MR imaging. Am. J. Roentgenol. 1992 158: 119-123.
- Jaume Llauger, Jaume Palmer, Núria Rosón, Sílvia Bagué, Àngels Camins, and Rosa Cremades. Nonseptic Monoarthritis: Imaging Features with Clinical and Histopathologic Correlation. RadioGraphics 2000 20: 263S-278S.