Warth LC, et al. - In this study, the impact of posterior cruciate ligament (PCL)-resection on in vivo tibiofemoral joint space dimensions in a cohort of modern total knee arthroplasties (TKAs) was ascertained. Researchers performed tibiofemoral joint space measurements during 129 standardized TKAs by two arthroplasty surgeons. They conducted a medial parapatellar approach, computer navigation, and provisional bone cuts in all cases with particular attention to preserving PCL integrity. They assessed the tibiofemoral gap with a calibrated tension device at extension, 45-degrees, and 90-degrees before and after complete PCL-resection. The results of this study indicate that tibiofemoral joint space increased progressively from extension to mid-flexion through deep-flexion after PCL-resection, yet was substantially less than reported in historical studies. Nevertheless, in the flexion-space opening, large variation was observed with some patients failing to increase the flexion-space whatsoever with PCL-resection. It was demonstrated that runs counter to conventional TKA understanding and should be recognized in modern surgical education.