1. A data processing method performed in a computer having a memory for determining six parameters of a contact position of a physiological or artificial joint which connects two bones, wherein the contact position is a relative position between the two bones in which physiological or artificial surfaces defined at ends of the two bones respectively by the bones or by implants carried on the bones are in contact with each other, and wherein three of the parameters define a translational shift and three of the parameters define a rotational shift, the method comprising: acquiring a plurality of sample contact position datasets, each dataset comprising six parameters that correspond to the six parameters describing the contact position; acquiring a subset of n of the parameters of the contact position as an input parameter dataset; selecting at least two of the sample contact position datasets based on the input parameter dataset; and determining the m=6−n remaining parameters of the contact position based on the at least two selected sample contact position datasets.