Image of knee prosthesis for knee replacement surgery

Knee Prosthesis

     Knee replacement surgery is an option many consider when pain is inhibiting movement or the knee itself or the knee is so unstable that a patient is incapable of function such as walking.    In some cases the damage to the bone itself, or supporting tissues, is so severe that only knee replacement surgery is viable.   In other cases the cause of the pain may be the lack of strength of the musculature and that lack of strength is allowing the compression of nerves or support tissue. IN many cases the lack of muscle strength has allowed bone on bone which is a destructive process.   In the latter case the use of functional restoration training may avoid the necessity of any prosthetic knee implant surgery. 

    In either case it's necessary to understand there is a rehabilitation that must occur before a patient can restore the function of the knee joint.


  It's very necessary to try to enter the surgery with the most muscle strength one can have.   In basically any situation where muscle tissue is cut, or muscle tissue does not move for a time period,  there occurs what is called "muscle atrophy".   Simply put the muscle loses strength due to lack of movement or tissue destruction.   The lack of movement causes the loss of strength, lack of elasticity of the muscle cells and prohibits a patient from gaining full range of motion until the strength is restored and the pain is lost. 

   When possible a patient should begin to strengthen the muscles prior to surgery.   Immediately upon surgical implant of the knee prosthesis, the patient should begin exercising the surrounding muscles to retard further disuse atrophy and/or begin to restore strength to the muscles.  In many situations, even before the patient regains consciousness, a CPM ( constant passive motion machine) will be used to move the knee joint back and forth passively, to stop the disuse atrophy and to increase blood flow to the joint area.  The patient should inquire with the orthopedic surgeon if a CPM machine would reduce the rehab. time.   

   Often a CPM machine is used conjunctively with a "muscle simulator" to actively stimulate motor nerves to keep the muscles contracting and relaxing.  The use of electrotherapy makes the muscles function and has been used to actually increase the rate of healing of the damaged tissues resulting from the knee replacement surgery.   Electrotherapy is often used after the CPM machine is removed to complete the healing of the tissues around the knee joint quicker than would be the normal biological process of tissue repair. 

   Exercising before and after knee replacement surgery is indicated for most knee prosthesis and the sooner muscle strength is restored and range of motion is full, then the better the patient outcome is.