A 12-Month Prospective, Post-Market Study of Early Postoperative Compex® Rehab NMES Use in Total Knee Arthroplasty Patients

Neuromuscular electrical stimulation (NMES) for muscle strengthening and training has been in use since the 1970s, but questions still remain regarding its effectiveness with different patient populations, the duration of use and specifics regarding the stimulation itself, such as length and type of electrical impulse. NMES works by passing electrical impulses through the muscles to get them to contract. These impulses mimic the body's natural neural activity (action potential) to cause a contraction. The goal with NMES is to strengthen the muscle sooner by using muscle re-education. The quadriceps is weakened and sometimes slow to respond after knee surgery. A weak quadriceps muscle after surgery can be a contributing factor to dissatisfaction with the surgical result. When the quadriceps are weak or not firing properly, forces are transferred to areas such as the knee joint placing an additional strain on the replaced joint and contributing to knee pain, swelling and inflammation. If we can get patients' quads firing better and sooner, we hope we would also see better short-term and long-term functional outcomes and more long-term satisfaction than is presently reported. Study Enrollment We are looking for 60 patients to participate. We are randomly assigning 30 participants to receive the standard therapy regimen and 30 to follow the standard therapy regimen with the addition of using an NMES treatment twice a day, every day, for a ten-week period. Patients in the therapy with NMES treatment group will keep a tracking log of their use at home and will turn in the units at the 10-week appointment. The unit is easy to use and all participants are given specific instructions on its use. All participants complete baseline muscle testing before their surgery and then again at two-week, six-week, ten-week, and one-year appointments. The muscle testing consists of a battery of functional measures to assess the quadriceps such as the Timed Up and Go test (TUG), Six Minute Walk test (6MWT), Single Limb Stance (SLS) and others. All testing is conducted at Indiana Orthopaedic Hospital South's physical therapy department.

When designing this study we worked closely with the department to make sure the intended tests were appropriate both for our study and the facility; the input from the staff was and continues to be integral to this study's success. It is too early to report any findings and we are still enrolling patients. If effective, the NMES treatment should improve quadriceps activation and functioning early on after surgery, which will hopefully allow the patient to experience less pain and have a quicker functional recovery than a patient who did not use the NMES. Only time will tell if this is a logical conclusion and if NMES as a standard postoperative therapy would be beneficial for our patients. We anxiously await the outcome of the study.