OBJECTIVES: The aim of the study is to compare the burden of displaced and undisplaced medial femoral neck fracture treated with primary osteosynthesis in patients with and without complication under 60 years on 2 years follow up. METHODS: Data derive from the financial database of the National Health Insurance Fund Administration and based on the S7200 code (femoral neck fracture) of the International Classification of Diseases (ICD) tenth revision. and the surgical codes of the Hungarian Homogenous Disease Groups related to primary treatment of fracture in 2000. During the two years follow up we analysed the health insurance costs, ratio of further treatments, the ratio of multiple treatment. The health insurance costs include the reimbursement of acute and chronic inpatient care, outpatient care and sick-pay costs. Exchange rate: 1EUR=253,23 HUF. RESULTS: Altogether 413 patients were included into the study, 154 undisplaced and 259 displaced femoral neck fracture. Undisplaced fracture: average cost per patient €1993 for all the patients, €3682 for patients with complications. The ratio of further treatment is 12.9 % (secondary prosthesis 6.5 %), ratio of multiple treatment 2.6 %. Displaced fracture: average cost per patient €2249 for all the patients, €4074 for patients with complications. The ratio of further treatment is 21.6 % (secondary prosthesis 12.4 %), ratio of multiple treatment 4.6 %. CONCLUSIONS: In case of using osteosynthesis after displaced femoral neck fracture, the ratio of further treatment (secondary prosthesis and multiple treatments) and the costs are significantly higher.