Background: Previous investigations on CR TKA have shown that a tibial cut performed en-bloc is likely to cause the division of most of PCL fibres insertion, thus suggesting that other techniques rather than an en-bloc osteotomy should be performed to preserve the PCL during TKA. A previous MR investigation has shown that to preserve the PCL insertion the thickness of the tibial cut should range between 4 and 6 mm, depending on the sagittal slope of the tibial cut and that of tibial plateaus of the operated knee. Based on these findings, an alternative technique to preserve the PCL insertion including the execution of a double tibial cut has been investigated. Objectives: To assess whether the execution of a double tibial cut may be a reliable technique to preserve the PCL during the tibial osteotomy in TKA. Study Design & Methods: A consecutive series of patients undergoing TKA was analysed prospectively. Group 1 included 40 patients with a mean age of 74.7 yrs in whom a standard en-bloc tibial resection was performed with 3° of posterior slope and a thickness a 10 mm. Group 2 included 40 patients with a mean age of of 76.2 yrs in whom the tibial cut was performed using a double cut technique. In particular, using a posterior slope of 3°, a first full-thickness tibial cut averaging 5 mm (range 4-6 mm) including a layer of cartilage and subchondral bone extended to the posterior tibial cortex was performed. A second cut extended 5-7 mm anteriorly to the posterior cortex was then performed in order to reach a total thickness of 10 mm (Fig.1 and 2). Patients showing severe deformities or previous knee surgeries requiring a PS implant were excluded. The preservation of PCL was evaluated intraoperatively and by measuring femoral rollback either intraoperatively and on postoperative radiographs. Clinical evaluations were performed 3-6 and 12 months after surgery using KSS. Results: PCL preservation after the tibial cut was complete in 16 patients of Group 1 and 33 of Group 2, partial in 13 of group 1 and 6 of group 2 and insufficient in 11 and 1 patients of group 1 and 2, respectively (p=0.0001). Intraoperative rollback averaged 1.3 mm in group 1 and 3.8 mm in group 2 (p= 0.001). Postoperative rollback averaged 1.1 mm (-3-3.6mm) in group 1 and 3.3 (2.3-7mm) in group 2 (p=0.001) (table I). A paradoxical roll back was found in 12 patients of Gr 1 and in 1 patients of group 2 (p=0.0001). At the 3 and 6 months follow-up, the KSS was, respectively, 72 and 81 in Group 1 and 68 and 82 in Group 2 (p>0.05). At the 12-months follow-up KSS was 91.4 and 94.3, respectively (p=0.05). Knee flexion was on average 114° in group and 119° in group 2 (p=0.04). Conclusions: A iatrogenic injury to the PCL may occur during an en-bloc resection of proximal tibia and may explain the paradoxical rollback reported under fluoroscopic analysis in CR TKA. An island of cortico-cancellous bone may be preserved anteriorly to the PCL insertion, but the results of this technique have not been reported. The double cut technique is an alternative way to perform the tibial osteotomy to spare the PCL. The thickness of the first cut may vary depending on the sagittal slope of the tibial cut and the sagittal slope of tibial plateaus of the operating knee. This preliminary investigation has shown that the technique is safe and allows the preservation of the PCL in higher percentage of cases than an en-bloc resection of proximal tibia. In the series analysed, patients operated with this technique showed absence of paradoxical rollback in all but one case, a better rollback and higher flexion at the 12-months follow-up.