Post-operative pain following total knee replacement (TKR) is a common challenge, impacting a patient's initial
mobility and overall recovery. Many individuals experience significant discomfort in the days and weeks following
surgery, hindering their ability to participate fully in physiotherapy and other rehabilitation activities. This pain
can make even simple movements difficult, such as getting out of bed or walking short distances, which can
significantly delay the recovery process. Various pain management strategies exist, ranging from pharmacological
interventions to non-pharmacological approaches. Physiotherapy offers a range of non-pharmacological alterna-
tives, including Transcutaneous Electrical Nerve Stimulation (TENS). We will explore how TENS therapy,
particularly when delivered using a device like Axonease, can play a crucial role in reducing post-surgical pain and
fostering a successful rehabilitation journey for a knee replacement patient. The prevalence of post-operative pain
highlights the need for effective pain management strategies. This case study will explore the application of TENS
therapy, within the boundaries of physiotherapy practice, to manage pain following knee replacement surgery.
This example highlights the potential of TENS as a non-invasive, drug-sparing approach to pain management,
contributing to a more comfortable and efficient rehabilitation process. The psychological impact of chronic pain
on patients undergoing rehabilitation can be significant, potentially leading to anxiety and decreased motivation.
TENS can potentially alleviate these issues, thereby enhancing their engagement in the recovery process.
TENS (Transcutaneous Electrical Nerve Stimulation) is a physiotherapy technique that utilizes gentle electrical
pulses to stimulate nerves through the skin. It's a non-invasive treatment option often used for post-operative
pain management. The electrical impulses from the TENS unit can effectively "block" pain signals from reaching
your brain. It's like closing a gate to pain, allowing you to feel more comfortable. Furthermore, TENS is believed
to stimulate the release of endorphins, the body's natural painkillers, contributing to a sense of well-being
and reduced discomfort. A TENS device emits variable electrical impulses, with most applications using higher
frequencies between 40 and 150 Hz, with a short rectangular-shaped pulse duration typically around 50 μs. TENS
is a widely promoted intervention for chronic pain and spasticity, most commonly being prescribed for temporary
relief of neck and low back pain. A TENS device emits variable electrical impulses. Low frequencies between 1
and 4 Hz with high intensity are less commonly used in a theoretical attempt to inhibit peripheral large-diameter,
nociceptive transmission neurons. Axonease offers pre-programmed settings and customizable parameters,
allowing physiotherapists to tailor the treatment to individual patient needs. These features allow physiotherapists
to fine-tune the treatment for different pain conditions and patient profiles. The safety considerations of TENS
therapy include contraindications and potential side effects.
Meet Mrs. Eleanor Vance, a 68-year-old woman who, like many others, underwent knee replacement surgery to
relieve the pain of osteoarthritis. Her osteoarthritis was severe, significantly impacting her mobility and quality
of life. Before surgery, Mrs. Vance experienced chronic pain levels consistently rated between 7 and 9 on a
0-10 pain scale, even with medication. She was understandably anxious about the surgery and the recovery
process. Following the surgery, Mrs. Vance experienced significant post-operative pain, which limited her ability
to participate fully in her physiotherapy sessions. Her pain levels were consistently rated between 6 and 8 on a
0-10 pain scale, despite regular pain medication. This made even simple movements difficult and significantly
impacted her quality of life. She struggled with basic exercises like straight leg raises and short walks, which
hindered her progress. The emotional toll of the pain was also evident, as it affected her mood and motivation.
The physiotherapy team, after a thorough assessment, incorporated TENS therapy into Mrs. Vance's rehabilitation
program. Using the Axonease device, electrodes were strategically placed around her knee joint, targeting the
areas of greatest pain. The TENS unit was initially set to a high-frequency mode (around 80 Hz) with a comfortable
intensity level. The treatment sessions lasted for approximately 30 minutes and were administered twice daily, in
conjunction with her regular exercises.
The physiotherapy intervention for Mrs. Vance was comprehensive, including range-of-motion exercises,
strengthening exercises, and gait training. The specific range-of-motion exercises included gentle knee flexion
and extension, while strengthening exercises focused on quadriceps sets and hamstring curls. Gait training
involved practicing walking with a walker and gradually progressing to a cane. However, her pain was a significant
barrier to progress. The introduction of TENS therapy, using the Axonease device, aimed to address this limitation.
The specific TENS protocol involved the following:
• Electrode Placement: Electrodes were placed around the knee joint, ensuring that they surrounded the
primary areas of pain. Common placements include above and below the knee, or on either side of the patella.
The physiotherapist carefully considered Mrs. Vance's pain referral patterns to optimize electrode placement.
• Parameter Settings: The Axonease device was initially set to a high-frequency (80-120 Hz), low-intensity
mode. The intensity was gradually increased until Mrs. Vance reported a comfortable tingling sensation.
• Treatment Duration and Frequency: Each TENS session lasted for 30 minutes and was administered twice
daily, before and after her exercise sessions.
• Progression: As Mrs. Vance's pain levels decreased, the TENS parameters were adjusted to optimize its
effectiveness. This involved experimenting with different frequencies and pulse durations, always within the
scope of physiotherapy practice and patient comfort. The physiotherapist educated Mrs. Vance on how to monitor
her pain levels and adjust the TENS parameters within safe limits.
A thorough assessment by a physiotherapist is vital before starting TENS therapy.
Within a few days of incorporating TENS therapy, Mrs. Vance reported a noticeable reduction in her pain levels.
Her pain scores decreased from 6-8 to 3-5 on the pain scale. This improvement allowed her to participate more
actively in her physiotherapy sessions, leading to increased range of motion and improved muscle strength.
Her range of motion improved significantly, allowing her to bend her knee further and walk with greater ease.
Her muscle strength also increased, enabling her to perform exercises more effectively. Beyond pain relief, Mrs.
Vance was able to reduce her reliance on pain medication, minimizing potential side effects and feeling more
in control of her recovery. This aligns with research suggesting that the addition of TENS, as an adjunct to a
multi-modal pain protocol following total knee arthroplasty, might help reduce reported pain and narcotic use
during the first 24 hours, although no beneficial effect was noted at 2-weeks. Mrs. Vance's quality of life improved
significantly, with better sleep, reduced side effects from medication, and increased energy levels. Several months
after completing physiotherapy, Mrs. Vance continued to manage her pain effectively with a combination of
exercise and, occasionally, TENS. This highlights the potential for TENS therapy to reduce the risk of chronic
pain development after TKR.
Working with a qualified physiotherapist is key to getting the most out of TENS therapy. They'll assess your
specific needs and create a personalized plan just for you. Incorrect electrode placement or inappropriate
parameter settings can reduce its effectiveness or even cause skin irritation. It is essential to consult with a
qualified physiotherapist who can assess your individual needs and develop a personalized TENS protocol. The
physiotherapist will consider factors such as the location and intensity of your pain, your medical history, and
any other relevant conditions. They will also educate you on how to use the TENS unit safely and effectively at
home. This includes instructions on electrode placement, parameter adjustments, and troubleshooting common
issues. Remember, TENS should always be used as part of a comprehensive physiotherapy program, not as
a standalone treatment. The use of TENS requires careful consideration and should always be guided by a
healthcare professional. The physiotherapist will provide detailed instructions on proper electrode placement techniques,
including diagrams and videos. They will also discuss the importance of skin preparation and hygiene to prevent
skin irritation. The different TENS parameters (frequency, pulse duration, intensity) and their respective effects
on pain relief will be explained.
Mrs. Vance's story exemplifies how TENS therapy, when integrated into a comprehensive physiotherapy program,
can empower patients to take control of their pain and accelerate their recovery after knee replacement surgery.
By providing a non-invasive, drug-sparing approach to pain management, TENS can improve patient comfort,
enhance participation in rehabilitation, and ultimately lead to better functional outcomes. The use of devices
like Axonease further enhances the accessibility and personalization of TENS therapy. With its user-friendly
interface and customizable settings, Axonease allows physiotherapists to tailor the treatment to individual patient
needs, maximizing its effectiveness and promoting patient engagement. This technology-assisted rehabilitation
aligns with the broader trend of incorporating innovative tools to improve outcomes following total knee or hip
replacement for people with osteoarthritis. Technology-assisted rehabilitation is becoming increasingly common.
The broader implications of technology-assisted rehabilitation include improving patient outcomes and reducing
healthcare costs.
In conclusion, the case of Mrs. Vance demonstrates the potential of TENS therapy, particularly when delivered
through devices like Axonease, to significantly reduce post-operative pain and improve rehabilitation outcomes for
knee replacement patients. While the evidence base for TENS is still evolving, its non-invasive nature and potential
for pain reduction make it a valuable tool in the physiotherapist's toolkit. Managing pain with medications is also
important, but TENS offers a non-pharmacological alternative or adjunct. Remember, effective pain management
is a crucial component of a successful knee replacement recovery, and TENS therapy may be a valuable addition
to your rehabilitation journey. The key findings of the case study and the supporting research evidence highlight the
importance of individualized assessment and treatment planning by a qualified physiotherapist. TENS therapy can
empower patients to take control of their pain and improve their quality of life. If you're considering knee replacement
surgery or are currently experiencing post-operative pain, discuss the potential benefits of TENS therapy with your
physiotherapist. A personalized assessment and treatment plan can help you determine if TENS is right for you and
ensure that you receive the maximum benefit from this innovative pain relief modality.