A live display apparatus for setting extension and flexion limits in a continuous passive motion (CPM) system. The CPM system includes a carriage for supporting a patient's limb through a range of reciprocal angular movement, a drive motor for driving the carriage, a carriage state sensor for providing a signal representative of carriage state and a control unit responsive to the carriage state sensor for controlling the drive motor. The live display apparatus includes an operator controlled extension limit select switch which is operatively coupled to the control unit. The select switch causes the carriage to be driven through its range of movement to a desired extension limit when actuated during an extension limit select mode. Data representative of the selected extension limit is stored in extension memory. An extension limit display is responsive to the control unit and provides a visual display indicative of the extension limit selected. An operator controlled flexion limit select switch is operatively coupled to the control unit, and causes the carriage to be driven through its range of movement to a desired flexion limit when actuated during a flexion limit select mode. Data representative of the selected flexion limit is stored in flexion memory. A flexion limit display provides a visual display indicative of the selected flexion limit.