One of the most widely used methods for the post-surgical mobilization after ACL is the use of Continuous Passive Motion (CPM) devices. These machines are meant to drain residual fluid from the articulation and maintain the mobility of the joint and muscles in the knee. Even though studies show that, an early mobilization after surgery is beneficial to the rehabilitation of the knee joint, recent studies are questioning the efficiency of the CPM when compared with the goal of application. While literature suggests that efficacy of CPM are related with the magnitude of knee flexion and the Range of Motion (ROM) achieved some studies show that the range of motion measured by the CPM is considerably less than the actual ROM.