Fig. 1

Intraoperative view of the pre-cut technique. A Appearance of the pre-cut trial component (left) and the cutting guide (right). Three sizes were available according to the patient’s bone size. B. A cutting guide for posterior femoral condylar pre-cut osteotomy. It enables surgeons to make a 4-mm pre-cut from the posterior femoral condylar axis. C. Pre-cut trial with a thickness of the portion of the posterior condyle 4 mm thinner than the ordinary implant. D. Removal of the posterior femoral condyle osteophytes. E, F With the pre-cut trial component inserted, the temporal FG (E) and EG (F) were measured using the navigation system at 90° knee flexion and knee extension. The spacer block was put in and out using two fingers smoothly with adequate tension and without lifting off. EG extension gap, FG flexion gap