Everyone who goes into surgery for a total knee replacement (TKR) knows the leg is weak from pain and disuse. When and how does muscle strength come back after the operation? Studies show that many patients have weakness and loss of function that can go on for years.
Electrical stimulation of the muscles improves strength in young adults. What effect will it have on older adults after a TKR? Physical therapists enrolled patients who were having both knees replaced at the same time in a study of electrical stimulation. Having subjects with both knees replaced gave researchers a chance to use electrical stimulation on only one side. Results were then compared to the patients’ own knee that did not get electrical stimulation.
Two groups were formed in this study. One group received the same exercises for both legs. The other group received neuromuscular electrical stimulation (NMES). The NMES group did exercise on one side and exercise along with NMES on the weaker leg.
Everyone started their programs after the staples were removed (about three to four weeks after surgery). Patients were treated three times a week for six weeks, for a total of 18 visits. They were followed for up to six months. Knee range of motion and quadriceps muscle strength testing were done at regular intervals.
Legs with NMES were found to be equal to or stronger than the other side. The patients were able to keep this strength even six months later. Strength continued to improve over the six-month period, but the major improvement occurred in that first three weeks.
The authors suggest a formal strength training program after TKR isn’t needed for a full six weeks. Using NMES in a rehab program after TKR may increase quadriceps muscle strength faster than just using a traditional exercise program. Three weeks may be all that’s needed. This was a small study, so final recommendations will depend on results from a larger study in the future.