Probe (1) used during a total knee arthroplasty for measuring forces and locations of their points of application and thereby moments comprising A) two load sensitive plates (2 3) apt to be inserted in one joint-compartment of a knee joint each and each being provided with a top surface (6) and a bottom surface (7) B) at least two load sensors (10) situated on the top surfaces (6) and/or the bottom surface (7) of beach load sensitive plate (2 3).