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A Case of Successful Muscle Stimulation after Total Knee Replacement

Over 200,000 knee replacements are done every year in the United States. People receiving new knee joints average 68 years old. A potential problem after this operation is weakness of the thigh muscles (called the quadriceps femoris). This weakness often persists even with exercise.

Loss of strength before surgery is usually caused by aging and arthritis. And if these don't spell trouble, the operation itself affects the muscles even more. Leg weakness can keep a person from getting back to daily activities such as walking, climbing stairs, standing up from a low chair, or getting in and out of a car.

Exercise is used to build up the muscle after knee surgery, but there is often less strength compared to the other leg. In the case of one 66-year-old man, electrical stimulation was combined with exercise to increase the force of the quadriceps muscles. Electrical stimulation (ES) is used most often by a physical therapist to retrain and build up muscles. ES works by sending an electric current through a small patch, called an electrode, that's placed on the skin over the muscle. This is a safe and pain-free way to help the muscle use more fibers and with greater force.

Three weeks after the knee replacement, this gentleman began doing physical therapy. He attended 11 sessions that included ES, stretching exercises, and strengthening exercises with weights. By measuring his muscle strength before and after this program, the physical therapist showed that the leg with the knee replacement was almost as strong (93 percent) as the other leg.

ES is a safe and effective way to strengthen the quadriceps muscles after total knee surgery. The strength gained is more than would happen from simply doing exercises. Using ES along with an exercise program can help older adults get back to regular activities sooner than normal after total knee replacement.

References: Michael Lewek, PT, MTP, et al. The Use of Electrical Stimulation to Increase Quadriceps Femoris Muscle Force in an Elderly Patient Following a Total Knee Arthroplasty. In Physical Therapy. September 2001. Vol. 81. No. 9. Pp. 1565-1571.

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