Hemarthrosis

Hemarthrosis (or haemarthrosis, plural h(a)emarthroses) is a bleeding into joint spaces.

Causes
It usually follows injury but occurs mainly in patients with a predisposition to hemorrhage such as those being treated with warfarin (or other anticoagulants) and patients with hemophilia.

It can be associated with knee joint arthroplasty.

Treatment
In hemophilia it may occur spontaneously, and recurrent hemarthroses are a major cause of disability in that patient group due to hemophilic arthropathy, requiring synovectomy, joint replacement and increased medical therapy to prevent further bleeding episodes, although it is controversial whether clotting factor administration adequately prevents hemarthroses.

Complications
Up to a quarter of all severe ligament or capsular knee injuries leading to a haemarthrosis are associated with cartilage damage that can lead to progressive degenerative arthritis.