The number of hip, knee, shoulder, ankle and elbow prostheses, as well as the amount of economic resources dedicated to this type of intervention, are constantly growing. Prosthetic interventions are not always effective, in some cases they have shown poor results and a high incidence of infections. For rare diseases such as haemophilia and haemophilic arthropathy, collecting retrospective and prospective data is the first step in estimating prevalence or incidence and the opportunity to stimulate future research and to facilitate recruitment into studies. Such studies may present data on the demographic aspects of patients to describe the population receiving the procedures, the patterns of use over time, the risks of review and the outcomes reported by patients. This retrospective/prospective study aims to describe and analyze the risk factors associated with the patient, the surgical technique and obtain outcomes.

Inclusion Criteria:

• adult patients with MEC (in particular Haemophilia A and Haemophilia B, with and without inhibitor, Von Willebrand's disease (VWD), other coagulation factor deficits)
• they are undergoing prosthetic surgery
• they have signed informed consent.

Exclusion Criteria:

• Subjects < 18 years old;
• Subjects with acquired haemorrhagic disorders
• Lack of signed informed consent.

adult patients with MEC