OBJECTIVES: To date, surgical interventions in people with haemophilia and high-titre, high-responding inhibitors have been largely restricted to life-threatening situations. This is to the detriment of patients who would benefit from surgery in terms of reduced pain, a reduction in the frequency of regular bleeding episodes and improved quality of life. However, with the development of recombinant FVIIa (rFVIIa: Novo Nordisk Ltd) elective surgery such as joint replacement can be carried out safely with effective haemostasis. This study examines the cost-consequences of surgical intervention in this patient group over time, to establish an estimate of the net cost of surgery. METHODS: A modeling framework has been used to estimate costs associated with haemostasis (rFVIIa treatment) in patients for nine surgical procedures, and to consider the cost-consequences of the intervention over a five-year time horizon. Key parameters in the model have been obtained from available literature (i.e. assumption of reduction in bleeding episodes) and expert opinion from a leading Haemophilia Comprehensive Care Centre (i.e. protocols for haemostasis required during orthopaedic surgery, physiotherapy and rehabilitation). RESULTS: For a typical person with haemophilia with inhibitors, weighing 75kg, experiencing one regular bleed per month in the affected joint, the costs for haemostasis associated with total hip replacement are an estimated £322,911. However, the net cost, when considering the reduced costs of treatment for regular minor bleeds over the following 5 years, are -£298,401 (cost-saving) when treating first line with rFVIIa. CONCLUSIONS: In addition to improved quality of life, orthopaedic surgery in people with haemophilia and inhibitors may be cost-saving when the reduction in regular minor bleeds is taken into account, and the subsequent cost consequences over-time offset the surgical costs.