Joint damage due to recurrent bleedings in Haemophilia is the cause for long-term disabilities. The pathogenetic mechanism of haemophilic arthropathy is multifactorial and includes inflammatory synovium-mediated and degenerative cartilage-mediated phenomenons, in addition to neoangiogenesis and bone loss. Free blood in the joint has a direct effect on cartilage and synovium, and the deposit of iron appears to play a pivotal role. Iron may promote the apoptosis of chondrocytes by catalyzing the formation of oxygen metabolites. Iron may also act on the synovial membrane by favouring its proliferation through the induction of proto-oncogenes involved in cellular proliferation and stimulation of inflammatory cytokines. Such degenerative and inflammatory processes occur concomitantly, but also independently. A reduction of bone mineralization is usually present as a part of the articular damage associated to a multifactorial mechanism: it seems that the molecular triad (osteoprotegerin/Receptor activator of nuclear factor kB/Receptor activator of nuclear factor kB ligand) probably plays a major role, inducing osteoclastic differentiation and maturation. These processes finally result in a fibrotic and irreversible altered joint, feature of haemophilic arthropathy.
Keywords: Arthropathy, Haemophilia, Haemarthrosis, Haemosiderin, Neoangiogenesis, Osteoporosis, Synovitis.