A motorized joint positioner includes a first holder configured for a first portion of a patient's anatomy to rest thereon, and a second holder configured for a second portion of the patient's anatomy to rest thereon. The joint positioner further includes a first robotic arm coupled to the first holder, and a second robotic arm coupled to the second holder. At least one of the first and second robotic arms comprises at least two joints providing movement of the corresponding first or second holder in at least two degrees of freedom. At least one of the first and second robotic arms includes an actuator controllable to position the corresponding first or second holder.