For knee reconstruction surgery involving replacement of an anterior or posterior cruciate ligament the present invention is in a process of verifying isometric ligament positioning at the femoral and tibial points of origin that includes, as apparatus, an arrangement of a stud (19) with attached suture (24) to serve as a mock ligament for testing isometry. In practice, as for an anterior cruciate ligament replacement procedure, a surgeon, observing on a fluoroscopic monitor (17), forms a tibial tunnel (18) from a point medial to the tibial tuberosity that exits a test or proposed tibial point of ligament origin. The stud (19) is arranged for turning on a driver (20) that is then passed through that formed tunnel and the stud is turned into the test or proposed femoral point of ligament origin. The driver (20) is then pulled out of engagement with the stud (19) exposing the suture (24) that extends from that stud, which suture (24) is attached under tension to a tension isometer (25) and the knee (10) is flexed through its full range of motion. With an isometrically correct selection of the femoral and tibial ligament points of origin, the tension isometer (25) will show no more than a three (3) pound change in force and no more than a two (2) mm change in ligament length or distance between the two points of origin over a full range of knee (10) flexure.