ELECTRICAL STIMULATION: Most often performed in outpatient orthopedic PT clinics for muscle re-education or pain control. The waveform, frequency and wavelength are different depending on the reason for using this modality.
With neuromuscular estim (NMES) two electrodes are typically used. Physical therapists use NMES to the quadriceps (specifically VMO) to regain quadriceps control to restore active terminal knee extension. There is an on and off time with NMES, and the patient is usually performing a quadriceps exercise during the time the NMES is on.
When electrical stimulation is used for pain control the term TENS is commonly used, which stands for Transcutaneous Electrical Nerve Stimulation, but even NMES is technically TENS. With TENS various set-ups can be used, but the most common is IFC (Interferential Current) at 80-150 Hz with 40% scan. This requires 4 electrodes in a crossed-diagonal pattern with the treatment area in the middle. An interference pattern is created, and varies throughout the treatment giving the sensation that the current is moving around, and preventing the patient from becoming too accustomed to the sensation. There can be some carryover of pain-relieving TENS effects between sessions, but I generally consider this to have a temporary effect lasting for up to 2-3 hours after the session. Often heat or ice is applied during the treatment as well. If you want to prescribe a home TENS unit for a patient for pain management we are happy to assist by working with vendors to obtain a device for a patient, and to teach them how to use the device.