Two high-quality studies (Beaupre 2001, Denis 2006) and five moderate-quality studies (Can 2003, Chen 2013, Herbold 2014, MacDonald 2000, Montgomery 1996) compared the utilization of continuous passive motion during hospital stay to no utilization of continuous passive motion. The combined results provide strong evidence that the surgical outcomes for those who used continuous passive motion are not better than for those who did not use continuous passive motion. Five of the seven studies measured outcomes of physical function and quality of life. Beaupre, Denis, Herbold, and MacDonald found no significant differences in a gamut of outcomes (Western Ontario and McMaster Universities Osteoarthritis Index, 36-Item Short Form Health Survey, Timed “up + go”, functional independence measure, and Knee Society Score). Chen reported better quality of life in the group that did not use continuous passive motion. Knee range of motion was investigated by Beaupre, Denis, and Chen. Meta-analysis showed no differences in knee range of motion. Complications were evaluated by Beaupre and Denis and were not statistically different between groups. Beaupra, Can, Chen, MacDonald, and Montgomery demonstrated that pain and stiffness were not decreased by continuous passive motion, whereas Denis reported significantly less pain in the continuous passive motion group (12 points difference in visual analog scale ranging from 0 to100). Meta-analysis from Denis, Herbold, and Montgomery showed no differences in length of hospital stay. One high-quality study (Lenssen 2008) demonstrated no statistically significant benefits in functional outcome scores or range of motion with the use of continuous passive motion in conjunction with physical therapy compared to physical therapy alone. The continuous passive motion was used for 17 consecutive days after surgery (about two weeks after discharge). Continuous passive motion should not be used routinely for every knee arthroplasty, as there have been no differences in active knee range of motion, pain, function, or quality of life (Harvey 2014). Continuous passive motion has been used after manipulation under anesthesia performed after knee surgery, although there are no studies to support this in the arthroplasty literature (Bram 2019).