1. Orthopaedic treatment of joint deformities in thirteen patients with haemophilia is reviewed over a period of seven years. 2. Forms of treatment discussed include open operation, manipulation under general anaesthesia, continuous traction, splintage and physiotherapy. The amount of intravenous therapy required for each form of treatment is indicated. 3. In discussing prevention of joint deformity the histories of a further eighteen patients have been taken into account. It is concluded that initially painless haemarthroses provide the main threat to joint deformity in haemophilia. 4. The best preventive treatment is early immobilisation followed by prolonged splintage and physiotherapy; intravenous therapy with antihaemophilic factor plays a less important role here than in other forms of haemorrhage. 5. Evidence is presented that joint deformity in severe haemophilia can often be entirely avoided.
