CPM Machine Troubleshooting

Problem – no power:  It may sound silly, but make sure the machine is plugged in to a working outlet and the power switch is on.  Check your circuit breakers and try the machine in a different outlet.  For any other power issues, it is recommended that you call the manufacturer or the provider.

Problem – squeaky machine:  Most machines run very quietly and smoothly.  Always be sure to place the knee CPM on a flat surface.  Machines are more likely to make noise it they are on an uneven surface.  If your machine begins to squeak, check to make sure the patient’s leg is not internally or externally rotating.  A rotated leg can put uneven pressure on the track, causing the components to grind.  If the CPM is noisy without a patient leg in the machine, apply WD40 or a similar agent on the propelling track both behind and in front of the connecting piece.  Adjust the CPM’s range of motion limits to run at full extension and full flexion and allow ample time (usually 20 minutes) for the lubricant to take effect.  If your machine continues to squeak, it may need to have its track components or belts thoroughly cleaned. 

Problem – not running proper range of motion:  Many CPM machines have a lock function which prevents patients from changing the range of motion beyond certain set parameters.  Always heed the directions given by the physician and DO NOT exceed any range of motion limits which were prescribed.  Check your owner’s manual or call your CPM provider if you are unable to unlock the range of motion on your hand control because all machine lock functions are different.  If your machine appears to be calibrated wrong, it is recommended that a professional Biomed technician re-calibrate your machine to the proper angles.  Do not use a machine which appears to be out of calibration for fear that the patient may be exceeding the prescribed range of motion. 

Problem – machine is migrating:  If you feel or see the machine migrating away from the patient with his or her leg is in the CPM, it may not be fit properly.  Try adjusting the length from the knee joint down to the foot plate.  Loosen the knobs which allow for this length to be adjusted, and while maintaining the knee’s position at the machine hinge point, either increase or decrease this length to the point where the foot is nearly touching the foot plate.  Be sure to tighten these knobs down again to keep this length set properly.  Some patient CPM pads come with a longer proximal pad which is designed to rest under the patient’s upper leg/hamstring area (including those provided by the medcom group).  If comfortable, have this piece of the pad kit rest underneath the patient to prevent the machine from migrating.  Finally, check to make sure the surface upon which the CPM is resting does not slant downward.  Patients who place their CPM on a firmer, more level surface will have fewer migration concerns to deal with.