Continuous passive motion device

Abstract

A continuous passive motion device comprises a base and femoral and tibial supports which rotate about a first pivot point located at the knee, the femoral support also rotating about a pivot point which comprises an extension of the base and is located adjacent the patient's hip. The motor is located in the base beyond the end of the travel of drive rods which extend from the base to the tibial support. The motor drives the foot of these rods forward and backward along the base. The drive rods move from a nearly horizontal positon relative to the base up to a vertical positon and past this vertical position. A camming mechanism is provided coupling the upper end of the drive rods to the tibial support, the camming mechanism being engaged when the drive rods are nearly vertical, to provide additional rotational force to the tibial support which is conveyed to the knee joint. In this way, a powerful bending force is conveyed to the knee, to thereby provide the necessary rehabilitating force to the knee joint. A specially designed hinge to provided at the joint between the femoral and tibial support to mimic the motion of the knee joint to make the use of this device more comfortable. A footplate is provided attached to the end of the tibial support and is connected by a short ankle rotation drive rod to a slot in a slider bar running parallel to the driver rods. In this way, the rotational motion of the foot support plate is caused directly by movement of the drive bars; this rotational motion can be adjusted depending on the point in the slot at which the adjustable drive rod is fastened. Special patient support pads are provided to be removably attached to the foot support plate, tibial and femoral supports; use of these pads allows for adjustment of the position in which a patient's leg rests on the leg support.