The use of tens machines for post surgical treatment is being widely used today in the orthopedic surgery area. The use of a tens machine is generally done as a way to prevent and control pain following trauma to tissue and bones caused by surgery. The tens unit electrodes are put on the patient while the patient is still unconscious and under anesthesia. In most cases the electrodes are sterile electrodes, however since the placement occurs after the wound is sutured it’s not necessary to only use sterile electrodes. This is a general guideline on how to place the electrodes and more importantly why.
If the tens machine is being used solely for pain then the electrode placement is not as crucial as it is when the electrical stimulus of the tens unit is being used to facilitate faster healing of the damaged tissues. We recommend the tens electrode placement include both aspects of post surgery healing, faster healing and less pain. Electrical stimulation has historically been used to heal non-union fractures, non healing decubitus ulcers, and the processes for those type uses is the same one uses for healing tissues following surgery.
Most clinicians are familiar with how electricity goes through the body from a tens machine. A tens machine has two “channels”. A channel is nothing more than a circuit from the tens machine and the machine sends electricity down one wire/cable to one electrode to go into the body. After the electricity enters the body it then takes the shortest easiest, less resistant, route to the other electrode that has been placed on the body. It is the area between the electrodes that is important.
Let’s take an ACL reconstruction on the knee and show how this works. Many surgeons and tens company reps will place two electrodes on the same channel directly above the knee on each side of the leg. The current flow is about 3 – 6 inches above the knee – NOT IN THE AREA WHERE THE SOFT TISSUE AND BONE TISSUE WERE INJURED. Because the current is solely flowing above the injured tissue there is probably no beneficial acceleration of healing of the bone or soft tissues due to the electricity. It simply does not go into the affected area therefore it’s unlikely faster healing occurs. There is some pain control from this tens electrode placement, but not any faster healing.
The proper placement would be to place one electrode behind the calf of the knee, and the other electrode on the top of the thigh about 3 – 4 inches above the knee. What this does is:
A. control the pain by stimulating the afferent nerves in the area, and
B. directs the electricity through the area where the surgery occurred.
Above is the better tens electrode placement following ACL surgery for pain control, and to get the patient healed and restore full function quicker.
Here is a video to show how the use of Functional electrical stimulation can be used to regain full activity levels 8 – 10 weeks after acl reconstructive surgery. This is especially important for the athlete or child participating in high school athletics.