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Continuous Passive Motion Machine (CPM)

In some instances, a continuous passive motion machine will be ordered for you to use while in the hospital after your total knee replacement.

  • The Continuous Passive Motion machine promotes knee flexion after surgery. The CPM should be used between 4 and 6 hours a day in 1.5-2 hour increments. This should be spread out throughout the day.
  • If you are having bilateral knee replacement (both knees replaced) it is recommended that you use the machine for 3 hours on each leg.
  • Your head should be flat or slightly elevated when on the CPM machine.
  • Do not use the CPM machine when you are sleeping at night.
  • To increase the flexion (knee bend), press the upper right hand button (flexion) and then press the plus (+) sign in 2-3 degree increments. To decrease the angle, press the upper right hand button and then the minus sign. The machine should be stopped when your operated leg is straight and the angle is at or near zero.
  • You should not leave the machine on your leg when you are not using it.
  • When you are out of the CPM, a towel roll should be placed underneath your ankle with your knee straight for 10-15 minutes or as tolerated to promote knee extension.