Continuous Passive Motion

Continuous Passive Motion (CPM) is a postoperative treatment method that is designed to aid recovery after joint surgery. In most patients after extensive joint surgery, attempts at joint motion cause pain and as a result, the patient fails to move the joint. This allows the tissue around the joint to become stiff and for scar tissue to form resulting in a joint which has limited range of motion and often may take months of physical therapy to recover that motion.

Passive range of motion means that the joint is moved without the patient's muscles being used. Continuous Passive Motion devices are machines that have been developed for patients to use after surgery. The CPM machine helps restore range of motion, prevents pooling of blood and resulting formation of blood clots, and accelerates wound healing by increasing fluid circulation around the joint.

There are CPM devices for the knee, ankle, shoulder, elbow, wrist, and hand.

The physician prescribes how the CPM unit should be used by the patient (speed, duration of usage, amount of motion, rate of increase of motion, etc.). Your rehabilitation will consist of a series of progressive weight bearing, range of motion, muscle strengthening and cardiovascular exercises. Your strength should also improve gradually.

Medicare Information and Qualifications:

Continuous Passive Motion devices are used to exercise joints following injury or surgery. Two types of classifications for Continuous Passive Motion devices are one for knee only and the other is for exercise for use other than knee.

Recent questions regarding the exact nature of these devices reveal confusion regarding the nature and functionality of these devices. These coding guidelines clarify the types of products described by the CPM codes.

The first test of any durable medical equipment is that it be durable and capable of repeated use over the expected five year useful life expectancy. Elastic, fabric, single use, or light plastic devices are not durable and do not meet the test for DME.

Secondly, the equipment must be capable of continuous passive motion of the affected limb. These characteristics mean that the device must have inherent within itself the ability to move the affected limb:

  • in an appropriate plane of motion
  • in a continuous fashion
  • at the same rate of speed
  • for a prescribed length of time
  • with adjustable limits of range of motion
  • with an identical range of motion in each cycle
  • without any input from the patient by the contra lateral or other limbs
  • with easily accessible safety or cutoff switches

These characteristics require that the device be electrically powered, either by AC current or battery. Battery powered models must have an AC adapter for long term use.

The items listed below are often sold, prescribed or needed in addition to the equipment above.

  • Crutches
  • Bath bench
  • Raised toilet seat

Disclaimer: This is a sampling of information. Please refer to the CMS website ( and consult your own experts for additional information.