Knee Replacement Recovery: How to Ease Swelling and Stiffness (and Why PEMF Is a Game Changer)
So you've had a new knee. Congratulations! That's a big step towards walking, sleeping and living more comfortably.
But if you're a few weeks or months in and thinking "shouldn't this feel better by now?", you're not alone. Swelling, stiffness and aches are some of the most common things people come to us about at Sōma Sana, and the good news is that there's so much you can do to speed things along.
Let's talk about what's normal, what helps, and why joint replacement patients are some of the people who get the very best results on our PEMF bed.
Why is my knee still swollen months after surgery?
A knee replacement is major surgery. Your body is healing bone, muscle, ligaments, tendons and soft tissue all at once, and swelling is part of that repair process.
And you're far from alone if it's taking time. Research suggests that up to a third of people still have some discomfort or pain a year after a knee replacement.[3]
It's very common for swelling to hang around for three to six months, and some people notice a little puffiness for up to a year, especially after a busy day on their feet. It often comes and goes, feeling better in the morning and worse by the evening.
The one thing to watch for is swelling that suddenly gets worse, alongside redness, heat, a fever or pain in your calf. If that happens, contact your surgical team straight away, as these need checking.
Is stiffness after a knee replacement normal?
Yes, very. Your knee has been through a lot, and the tissues around it can tighten as they heal. Many people also spent months or years moving differently before surgery, so the muscles around the joint need time to wake up and remember their job.
Stiffness is usually worst first thing in the morning or after sitting for a while. Gentle, regular movement helps, and so does giving your tissues the right support to heal.
Everyday ways to support your knee replacement recovery
Keep up with your physio exercises, and add these simple habits to help things along:
Move little and often. Short walks and gentle bends through the day beat one big push.
Elevate your leg. Raising your knee above your heart helps fluid drain away.
Use cold therapy. An ice pack wrapped in a towel for 15 to 20 minutes can calm swelling after activity.
Prioritise sleep. Your body does most of its repair work overnight, so protect your rest.
Stay hydrated and eat well. Protein, fruit and veg all feed your healing tissues.
Pace yourself. Good days are brilliant, but doing too much can bring the swelling back the next day.
And if you want to take your recovery further, that's where PEMF comes in.
What is PEMF?
PEMF stands for Pulsed Electromagnetic Field therapy. It delivers powerful pulses of magnetic energy deep into the body, working at a cellular level to boost your natural repair processes.
At Sōma Sana in Cockermouth, we have Cumbria's only high-intensity full-body PEMF bed. You lie back fully clothed and relax for 40 minutes while it gets to work on everything from the new joint to the muscles that have been compensating for it. Lots of clients tell us it's the highlight of their week.
How can PEMF help after a knee replacement?
This is where it gets exciting. PEMF has been studied specifically in people recovering from knee replacement surgery, and the results are really encouraging.
In randomised controlled trials, people who used PEMF after their knee replacement had less pain, less swelling and better function than those who didn't.[1][2] Impressively, the benefits lasted long after treatment stopped. One study found fewer people in the PEMF group had severe pain or walking difficulties three years after surgery.[2] Another, in partial knee replacements, showed less pain, less swelling and fewer anti-inflammatory tablets needed, with results still showing at three years.[4]
A review of the research on PEMF after joint replacements found no adverse effects across the studies, and concluded that calming inflammation early with PEMF can improve functional recovery.[3] PEMF has also been included in a review of enhanced recovery interventions for knee replacement published in the Annals of the Royal College of Surgeons of England.[5]
Our clients tell us they notice:
Less swelling and puffiness around the knee
Easier movement, with bending and straightening feeling freer
More comfort in everyday life, from climbing the stairs to getting in and out of the car
Better sleep, which feeds straight back into healing
Relief elsewhere too, as hips, backs and the "good" knee have often been working overtime
Because our bed treats the whole body, you're not just supporting the new joint. You're supporting everything that's been carrying the load for it.
Can you have magnetic therapy with a metal knee replacement?
This is the question we're asked most, and the answer is yes.
Most knee replacements are made from metal and medical-grade plastic. These implants have no electronics, no battery and no circuitry, so they're not a reason to avoid PEMF. In fact, people with joint replacements are one of the groups we see most often on the bed, because they're one of the groups who benefit the most.
We simply tailor your session. Rather than applying a very high intensity directly into the new joint, we:
Lower the energy over the implant
Spread the field across a larger area, so the knee gets a gentler share
Give the knee a small, targeted amount, while the rest of your body gets the full benefit
The people we don't treat on the bed are those with implanted electronic devices, such as pacemakers, cochlear implants or some nerve stimulators. That's a completely different situation from a metal and plastic joint, and we take everyone through a full health questionnaire before their first session.
What does a PEMF programme look like?
We usually start with a block of six 40-minute sessions, completed over two to six weeks. After that, we review your progress together, and many clients move to weekly or monthly maintenance once they've reached their goals.
Just let us know when you had your operation and how your knee is feeling, and we'll build your programme around where you are in your recovery, whether that's six weeks or six years post-op.
If you'd like to give your knee replacement the very best support, we recommend combining PEMF with red light therapy. Red light works closer to the surface on your scar and tissues while PEMF reaches deep into the joint, so together they cover everything. Read here about how adding red light can further benefit your recovery, and ask about our Recovery Pairing or memberships to do both.
Frequently asked questions
How long does swelling last after a knee replacement?
Swelling commonly lasts three to six months, and a little puffiness can come and go for up to a year, especially after busy days.
How can I reduce swelling after a knee replacement?
Gentle regular movement, elevation, cold therapy, good sleep and pacing yourself all help. PEMF has been shown in clinical trials to reduce swelling after knee replacement, making it one of the most effective ways to support your body as it heals.[1][2]
Is there research on PEMF after knee replacement?
Yes. Several randomised controlled trials have found less pain, less swelling and better function in people who used PEMF after knee replacement, with benefits lasting up to three years.[1][2][4]
Is it safe to have PEMF with a metal implant?
Yes. Titanium, cobalt-chrome and plastic joint implants are all fine, and a review of studies on PEMF after joint replacement reported no adverse effects.[3] We adjust the intensity over the joint to keep you comfortable.
Can I have PEMF after a hip replacement?
Absolutely. We use the same tailored approach for hip, shoulder and other joint replacements.
Who can't have PEMF?
Anyone with an implanted electronic device, such as a pacemaker or cochlear implant.
Will I feel anything in my knee?
Most people feel a gentle tapping or pulsing sensation. If anything feels uncomfortable, just tell us and we'll adjust it straight away.
Transform your recovery at Sōma Sana, Cockermouth
Whether you're in Cockermouth, Workington, Keswick, Maryport or anywhere across West Cumbria, we'd love to help you get the most from your new knee. Visit us at 39 Station Street, Cockermouth, book your first PEMF session online, or get in touch with any questions.
Your new knee has been through a lot. Let's get it feeling like it's always been yours.
References
Moretti B, et al. I-ONE therapy in patients undergoing total knee arthroplasty: a prospective, randomized and controlled study. BMC Musculoskeletal Disorders. 2012;13:88. https://doi.org/10.1186/1471-2474-13-88
Adravanti P, et al. Effect of pulsed electromagnetic field therapy in patients undergoing total knee arthroplasty: a randomised controlled trial. International Orthopaedics. 2014;38(2):397-403. https://doi.org/10.1007/s00264-013-2216-7
Lullini G, et al. Role of pulsed electromagnetic fields after joint replacements. World Journal of Orthopedics. 2020;11(6):285-293. https://doi.org/10.5312/wjo.v11.i6.285
D'Ambrosi R, et al. Pulsed electromagnetic fields improve pain management and clinical outcomes after medial unicompartmental knee arthroplasty: a prospective randomised controlled trial. Journal of ISAKOS. 2022;7(5):105-112. https://doi.org/10.1016/j.jisako.2022.05.002
Ibrahim MS, et al. An evidence-based review of enhanced recovery interventions in knee replacement surgery. Annals of the Royal College of Surgeons of England. 2013;95(6):386-389. https://doi.org/10.1308/003588413X13629960046435
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