Hyaluronic acid (gel) injections are a common treatment for knee arthritis. Many things affect how well they work — and one of the most important is aftercare. This guide explains exactly what to do after knee gel injections to get the most from your treatment. Recovery after a knee gel injection is usually relatively straightforward.
For how gel injections work and the evidence, see our hyaluronic acid guide; for the specific Durolane product, see the Durolane injection page.
What is a knee gel injection?
Hyaluronic acid — the “gel” — occurs naturally in the body and helps nourish cartilage and bone. You can take it as a tablet or use it in a face cream, but it works best injected straight into the joint. We aren’t certain how it works: it may lubricate the joint, or reduce the inflammation that drives pain and swelling. Either way, the evidence is strongest for knee arthritis, and high-molecular-weight gels such as Durolane work best.
Knee gel injection side effects
Gel injections are very safe, but, like all treatments, they have side effects:
- Mild flare — discomfort and swelling, usually starting after 24 hours and lasting up to two weeks. About 10–20% of people get a mild, self-limiting flare.
- Allergic-type reaction — rare (under 1 in 100), causing severe pain and swelling. More likely with inaccurate landmark-guided injections, and with gels made from chicken or egg protein. Usually treated with anti-inflammatories; occasionally the joint is drained and given cortisone.
- Infection — very rare (about 1 in 10,000). Choose a doctor who uses sterile technique, including sterile dressing packs, gloves, and ultrasound probe covers.
After a hyaluronic acid injection: the first day
Rest the knee for the rest of the day. Reduce walking, and use public transport or a car rather than walking home. Then:
- Keep the site clean. Leave the bandage on until the end of the day, then wash the area to keep bacteria away from the injection site.
- Don’t submerge the knee. Showering is fine, but avoid baths, hot tubs, and swimming pools for 24 hours.
- Use anti-inflammatory measures even without pain — ice for 10–15 minutes every 2–3 hours, and ibuprofen 400 mg three times daily for 24 hours (if safe for you). If a flare develops, continue using this anti-inflammatory regimen until the joint settles.
- Avoid heavy exercise — no running, long walks, golf or cycling. Avoid walking for fitness.
What should I do if I get pain after a knee gel injection?
If you experience pain but no significant joint swelling, you are one of the 10-20% of patients who develop a post-injection flare. Continue anti-inflammatory measures such as regular icing and ibuprofen (400mg three times a day) unitl the pain settles. You should avoid exercising the joint until pain settles.
If, however, you develop pain with significant joint swelling, you may have developed an allergic reaction also called ‘pseudosepsis’. This is a rare complication affecting less than 1/100 patients. If you suspect you have ‘pseudo-sepsis’, you should see your doctor again. For more information on ‘pseudosepsis ‘, click on the link: Are Durolane side effects really more severe?
How long should I rest after knee gel injections?
Rest the knee for two days, then gradually build up activity. If you develop a joint flare, keep resting until it settles, and continue using ice and regular ibuprofen.
When can I return to running?
Rest from running for seven days, and up to 10 days if your arthritis is more severe. You can start cycling after four days.
When can I return to the gym?
Avoid the gym for two days. After two days, resume upper-body and core work. Restart lower-limb weights after a week at 50% of your usual load, then build back to full lower-body weights after 14 days. However, you must ensure your joint is pain-free before you resume gym.
How much does a knee gel injection cost?
Dr Masci performs the gel injection as a one-stop appointment — consultation, diagnostic ultrasound, and the injection in a single visit. At the Chelsea clinic (the most cost-effective location), a hyaluronic acid injection is £470–£490 depending on the gel used (Ostenil Plus £470 / Durolane £490); other clinic locations cost more. See the full one-stop injection fees here, along with our clinic locations.
Frequently asked questions about knee gel injection aftercare
When can I drive after a knee gel injection?
Avoid driving on the day of the injection. You can usually drive the next day, unless a flare limits your ability to bend and straighten the knee.
Can I walk after a knee gel injection?
Reduce your walking for a few days. After a week, if there’s no flare, you can resume regular walking for fitness.
Should my knee gel injection be performed under ultrasound guidance?
Yes. Ultrasound improves accuracy and effectiveness — gel injections done under ultrasound work significantly better than blind ones. In a survey of over 1,000 patients, ultrasound-guided injections were linked to a 30%+ lower rate of knee replacement. Ultrasound also lowers the risk of an allergic reaction called pseudosepsis. Always check that your doctor uses ultrasound when performing a knee gel injection.
How long does a knee gel injection take to work?
Usually about four weeks, though some notice an effect at two weeks and others not until six. Don’t judge the injection too early.
How long does a knee gel injection last?
Generally 6–18 months. Higher-molecular-weight gels last longer — a single Durolane injection averaged over 400 days (around 15 months) for knee or hip arthritis. Also, if you respond to a Durolane injection, then you’re more likely to respond to repeat Durolane injections for up to 6 repeat injections before the effect lessens.
Can I have knee surgery after a gel injection?
Yes. A gel injection before surgery doesn’t raise the infection risk — unlike a cortisone injection, after which you should wait six months before knee surgery. However, you should always check with your surgeon before having any injection, including a gel injection before replacement surgery.
Final word from Sport Doctor London about knee gel injection aftercare
Knee gel injections are an effective treatment for knee arthritis, and proper aftercare helps them work effectively. Recovery after a knee gel injection is ususally straightforward: Rest the knee for 2 days, then gradually return to activity over 7–10 days, using ice and an anti-inflammatory if a flare occurs.
To book a one-stop ultrasound-guided knee gel injection in London, contact Dr Masci’s team here or call +44 (0) 203 488 0350.
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