CPM Unit following a Total Knee Replacement

CPM Unit Set-Up Following a Total Knee Replacement

 

 

Many times, immediately following a Total Knee Replacement surgery, a patient will wake up to find their surgical leg in a contraption that bends and straightens their knee.  This unit is called a C.P.M. or Continuous Passive Motion unit.  Some doctors strongly believe in its utility, while others are against it.  I have found that the doctors who oppose the use of the CPM unit feel this way because many times the unit is set up incorrectly, and this may cause more harm than good.  The purpose of the CPM is to bend and straighten the operative knee as much as the patient can tolerate in order to maximize their rehabilitation potential.  It is advised to use the unit 6-8 hours a day and to increase the flexion range of motion 5-10 degrees each day.  The initial goal following a Total Knee Replacement is full knee extension (full straight), while flexion takes a bit more time.  The goal range of motion of the knee is 0-135 degrees or symmetry between both knees.  For function, usually 0-117 degrees is needed.  For walking, 0-60 degrees is necessary.  Below is what a CPM looks like and how it should be set up.

 

 

Some points on the set up:

1.  Avoid direct contact between the skin and the metal parts of the unit.  Make sure the wool covers all areas that your leg will touch

2. Your foot should rest flat on the foot rest.  The length of the lower leg portion can be adjusted to guarantee this.

3.  Try to set it up so that your hip is not abducted out to the side but is in a more neutral position (foot in line with your hip)

4.  The hinge on the middle portion of the unit should line up with the center of your knee joint to allow smooth flexion/extension motion

5.  For this to be set up properly, the upper thigh section of the unit  has to be positioned very close to your hip.  You will practically be sitting on it.

6.  Make sure when the unit is bending your knee, that your knee and toes are pointing up to the ceiling.  You do not want any rotation of the hip.

7.  Use a tibial (lower leg) strap and/or thigh strap to maintain proper position

 

Following use of the CPM, make sure to use ice on your knee.

 

For more information on Total Knee Replacement Rehabilitation, go to www.strengthondemand.com