Haemophilia is a lifelong inherited bleeding disorder characterized by spontaneous bleeding resulting in painful joint deformities. Even if prosthetic surgery and the effectiveness and safety of clotting factor concentrate have improved the therapeutic options available, sometimes the orthopaedic surgeon has to treat substance losses. First, we have to distinguish: 1) sub-chondral cysts, 2) intra-osseous cysts, 3) pseudo-tumour (a chronic expanding blood cyst with the ability to displace and destroy adjacent tissues) Surgical treatment is in relation to its anatomical location and extension and is always associated with prolonged treatment with clotting factor concentrate. In our 20 years’ experience, we have used several therapeutic options. In some cases, we use filling with bone graft and fibrin seal and today platelet derived growth factor; in the others we have used amputation or custom made prosthesis.