A key element of patient care after hip and knee replacement is medication-based thrombosis prophylaxis. Due to decreasing lengths of acute hospital stays the question arises to what extent outpatients are taking responsibility thrombosis prophylaxis (patient pathway analysis).To analyze patient pathways a telephone survey of 668 patients was conducted. On average patients were interviewed 38 days following surgery with a focus on low molecular weight heparins. The analysis showed that nearly 90% of patients need to carry out thrombosis prophylaxis in an outpatient or home environment for at least 1 day and for 47.2% of patients a linking period between acute and rehabilitation stay is relevant. The obviously existing quantitative importance of outpatient thrombosis prophylaxis is also reflected by its duration and 45.7% of interviewed patients needed at least 5 days of outpatient prophylaxis.Outpatient thrombosis prophylaxis clearly makes high demands on the patients, in particular when combined with the task of administering complex forms of injections. Those involved in inpatient and outpatient provision of care should not assume that all patients carry out the necessary prophylaxis at the required level of reliability. On the contrary initial evidence shows that the non-adherence of patients during ambulatory thrombosis prophylaxis presents a genuine challenge to care providers.