April 7, 2025
Hip and knee surgery may include procedures like joint replacements or cartilage repair, each with unique recovery challenges such as pain, swelling, and temporary stiffness. TENS machines can aid post-surgery recovery by providing non-medicated pain relief, reducing the need for stronger pain medications, and supporting the healing process when used properly. However, it is essential to understand correct usage, including electrode placement and frequency settings, and to be aware of contraindications and potential side effects to ensure safety and effectiveness.
Going for hip and knee surgery can be considered an emergency or elective, depending on the urgency and severity of your condition. Examples of hip and knee surgery include joint replacements, fracture fixation, cartilage repair, and soft tissue repair. Each type of surgery is performed to treat specific conditions and injuries with varying levels of success.
The common theme between most surgeries is that an incision into the skin and layers of body tissue is made to gain access to the area that needs surgery. Even after the procedure, the body needs time to repair from the incision and operation area.
As a result, there may be residual pain, inflammation, and swelling that will likely occur afterwards [1]. Most of the time, these symptoms are temporary and improve with time.
The hip and knee joints are crucial for your ability to walk and be mobile. After surgery, you may be required to limit your movements to allow for recovery, including the usage of crutches or avoiding certain movements [1].
These restrictions will help settle short-term pain, swelling, and inflammation of the operated area, which are often the most common challenges after surgery. Additionally, these restrictions will allow for proper healing of the surgical site.
Some other temporary symptoms that are present after hip and knee surgery include joint stiffness, wound discomfort, and hesitation with movement.
Transcutaneous electrical nerve stimulation (TENS) machines are used to assist with pain relief, which can be beneficial during post-surgery recovery. This can even assist after major operations, such as using TENS during hip and knee replacement recovery.
TENS machines offer a non-medicated and safe treatment for post-surgery pain relief. They can be used alongside traditional forms of pain relief, including ice therapy, compression, and medication.
TENS delivers electrical impulses to help inhibit pain signals from the operated area. These electrical impulses can be adjusted by the user to customise the pain relief treatment. There are a couple of ways that TENS machines can help with pain, including the promotion of endogenous opioids in the body and stimulation of sensory nerves to distract away pain signals from the operated area [2].
A TENS machine will have varying levels of effectiveness for those undergoing lower limb surgery, such as knee and hip replacement recovery. According to a meta-analysis involving 529 patients, TENS was found to significantly reduce pain, decrease usage of morphine within the first 24 hours, and promote functional recovery [3].
To ensure effective usage of your TENS machine, the setup will be crucial. This will include positioning the electrode pads appropriately and selecting the most fitting settings for your circumstances. It is always important to speak to your surgeon and/or doctor to determine whether TENS treatment might be safe and effective for you after surgery.
Positioning of the electrode pads is crucial for successful pain relief. Typically, the pads need to be placed around the treatment area and each channel placed diagonally from one another. Please see an example of electrode placement for your hip and knee replacement recovery.
The positioning of the electrode pads after your hip replacement surgery will be dependent on the surgeon’s approach. This will affect where the incision is made. It’s important that the pads are not placed directly over the incision area.
Once again, the placement of electrode pads may vary depending on your surgeon’s incision of choice during your knee replacement. However, the incision location will usually be less variable than that seen with a hip replacement. Once again, avoid placing the electrode pads directly over the incision.
When purchasing your TENS machine, you may have access to several modes, including massage, EMS, and TENS. For the purpose of pain relief after knee and hip surgery, using TENS is the most researched and reliable method. Selecting TENS mode needs to be performed before starting the treatment.
The pulse rate, or frequency, is a measure of how many electrical impulses there are over a given period. Frequency can determine the type of pain relief that you can experience [3]. High frequency (100-200 Hz) allows for rapid and short-term pain relief. Whereas low frequency (1–5 Hz) allows for prolonged and longer-acting pain relief. Frequency needs to be set prior to treatment.
Pulse width describes the duration of each electrical impulse delivered into the body. Compared to other settings, such as mode, current, and frequency, there is less information about the effect of pulse width during TENS treatment. Researchers from the USA [4] have performed a computational study that showed that higher pulse widths reach deeper into the treatment area. Similar to frequency, this setting needs to be adjusted before the treatment.
Currently, there is little consensus about how often that TENS machine should be used for hip and knee surgery recovery. Some research has shown that 20 minutes of TENS has been shown to reduce pain after a total knee replacement [5]. However, treatment duration ranging from 5 to 60 minutes on a daily basis can be effective for pain relief. Typically, TENS machines can be safely used throughout the day. Although breaks are recommended to reduce skin irritation, Your doctor should always be consulted before usage, particularly if you have multiple conditions or illnesses.
When recovering from hip or knee surgery, using a TENS (transcutaneous electrical nerve stimulation) machine can help alleviate discomfort or pain. However, it is essential to follow safety guidelines to ensure its proper and effective use. If you are unsure, always speak to your surgeon before use. Here are key precautions to keep in mind [6]:
Avoid using the TENS machine on:
Special considerations that require consultation with your surgeon or doctor before usage:
Do not use the TENS machine if:
If you have any questions or concerns, reach out to your doctor or a physiotherapist experienced in electrotherapy.
When recovering from hip or knee surgery, using a TENS machine can be safe and beneficial if used correctly. However, it’s important to be mindful of possible side effects [6]. While most side effects are mild and can be prevented with proper use, any negative reactions should prompt you to stop using the device immediately. Though severe side effects are uncommon, they require immediate medical attention.
Common side effects:
If you notice any of these effects, stop using the TENS machine and consult a healthcare professional, such as a physiotherapist.
Severe side effects (often due to improper use or in individuals at higher risk):
If any severe side effects occur, discontinue use and seek immediate medical assistance.
