Blood-induced arthropathy in hemophilia: mechanisms and heterogeneity

Hemophilia A is an X-linked bleeding disorder that can be largely controlled by treatment with recombinant factor VIII. However, this treatment is only partially effective in preventing hemophilic arthropathy (HA), a debilitating degenerative joint disease that is caused by intra-articular bleeding events. The disease progression of HA has several distinct steps, beginning with hemophilic synovitis (HS), a hyperplasia of the synovial lining coupled with a neovascular response, followed by joint erosion with cartilage destruction and erosion of the underlying bone. The early stages of HA have certain features in common with arthritides such as rheumatoid arthritis (RA), whereas the later degenerative stages of HA have some similarities with osteoarthritis (OA). The main purpose of this review is to explore the similarities between HA with RA and OA and discuss how this information could potentially help understand the pathogenesis of HA and uncover new treatment opportunities.