The attending orthopaedic surgeon informs the patient both orally and in written. In case the patient grants permission he or she signs the consent forms, and fills out a standard survey (see Table 1 ). The orthopaedic surgeon now decides whether the patient is suitable for being a donor; he uses general and specific exclusion criteria (see Tables 2, 3 ). All criteria must be met; if not, exclusion necessarily follows. The orthopaedic surgeon examines the patient thoroughly: blood samples are collected to determine blood type, Rh-factor and erythrocyte sedimentation rate (ESR) ( Tables 4, 5) .