Arthrosamid® injections at Cambridge Hospital

What is Arthrosamid®?

Arthrosamid® is an injectable, non-biodegradable hydrogel that is made up of mostly water, with a soft, flexible structure. When it is injected into the knee, it blends into the soft tissue that lines the inside of the joint (the synovial membrane). This creates a flexible, cushioning, "shock-absorbing" layer inside the knee, which reduces friction between the joints, pain and inflammation. 

Arthrosamid® is specifically designed to treat the symptoms of mild to moderate knee osteoarthritis. It is not used for inflammatory arthritis (e.g. rheumatoid arthritis) or for people with severe (bone-on-bone) arthritis, as a knee replacement is a more effective treatment.

What are the benefits of Arthrosamid®?

Arthrosamid® cushions can offer many helpful benefits, especially for those with mild to moderate knee osteoarthritis who have not found sufficient relief from other non-surgical treatments like physical therapy, lifestyle changes, or other types of injections (e.g., steroids or hyaluronic acid).

The benefits of Arthrosamid® include:

• Pain relief: Arthrosamid® can provide long-lasting pain relief for people suffering from knee osteoarthritis.
• Improved mobility and function: By cushioning the joint, people often experience improved knee function, allowing them to return to daily activities.
• Minimally invasive: Arthrosamid® is a non-surgical procedure with few risks and a lower recovery time compared to knee replacement surgery.
• Non-surgical alternative: Arthrosamid can delay the need for surgery, such as knee replacement.

Complications of Arthrosamid® injections

Common side effects of Arthrosamid® injections include:

• Mild to moderate pain, bruising or swelling at the injection site.
• Infection at the injection site: If you experience redness, warmth or pus, please get in touch with your doctor or healthcare team immediately.
• Allergic reaction: To the Arthrosamid® injection, anaesthetic or equipment used during the procedure.

What happens during Arthrosamid® treatment?

Preparing for Arthrosamid®

Before your treatment, you will have a full consultation where your doctor will review your medical history and examine your knee. They will also review your X-rays or other scans to confirm your diagnosis. During your consultation, your doctor will also explain the possible risks and benefits of Arthrosamid®.

In most cases, you don’t have to fast beforehand, and you can eat and drink as usual, unless your doctor or healthcare team have instructed you not to. You may be asked to continue or temporarily stop any medications beforehand.

You may need to arrange transport home, especially if you’re going to have a local anaesthetic, as the numbness from the anaesthetic can make it difficult to drive.

Wear loose-fitting, comfortable clothing that allows easy access to the area being injected.

The procedure

The injection is a straightforward process and typically takes less than 30 minutes.

1. You will be positioned comfortably and the knee will be sterilised with an antiseptic.
2. Your doctor will inject a local anaesthetic into the knee to numb the area.
3. Using an ultrasound for guidance, your doctor will carefully insert a needle into the knee joint space and inject a dose of Arthrosamid®.
4. Once the injection is complete, your doctor will remove the needle and a small plaster or dressing will be applied to the injection site.

After Arthrosamid®

You should be able to go home shortly after the treatment. We recommend you have someone to take you home as you cannot drive until the local anaesthetic wears off, which can be several hours.

Recovering from Arthrosamid®

• First 48 hours: It is common to feel some tenderness, mild swelling and pain around the injection site. You can use painkillers or an ice pack to help reduce any discomfort. Rest your knee as much as possible and avoid standing for long periods, strenuous activities or heavy lifting.
• First two weeks: You can gradually return to your daily activities, but avoid strenuous activities, such as running, jumping or heavy lifting.
• Weeks 2 - 12: You will begin to feel the pain-relieving and cushioning effects of Arthrosamid®. This will gradually improve over several weeks as the hydrogel fully integrates with the soft tissue lining your joint (the synovial membrane).

Returning to work

• Desk-based jobs: Most people can return to work 1-2 days after Arthrosamid®. 
• Manual or active jobs: If your job requires standing, walking or physical labour, you will need a longer time to recover. Your doctor will advise when you can return to work.

What are the risks of Arthrosamid®?

Arthrosamid® is considered very safe, but as with any injection procedure, there are potential risks and side effects.

Common and mild side effects are usually temporary and related to the injection itself, such as:

• Pain, swelling, or redness at the injection site.
• Bruising.
• A feeling of fullness in the knee.

Rare risks include:

• Infection where the needle was inserted. If you experience redness, warmth or pus, please get in touch with your doctor or healthcare team immediately.
• Allergic reaction to the anaesthetic or equipment used during the procedure.
• Temporary increase in joint stiffness.

Your doctor will discuss all the potential risks and benefits with you in detail during your consultation.

How can I book an Arthrosamid® injection at Nuffield Health Cambridge Hospital?

FAQs

Is it a good idea to have physiotherapy following the treatment?

Structured rehabilitation will aid recovery following your treatment with Arthrosamid®. Your consultant will discuss this with you.

What to expect long-term, following treatment with Arthrosamid®

Supported by more than two decades of research, Arthrosamid® is suitable, safe and effective for any patient with knee osteoarthritis and is proven to maintain a significant, long-lasting reduction in knee pain even three years post-treatment.

When can you expect to feel less pain?

You are likely to feel some pain relief within 24 hours; however, it can take four to twelve weeks to feel the maximum benefit. Clinical data show that most patients start to feel an effect within a few weeks.

How soon could you return to normal activities?

As with any invasive joint procedure, it is recommended to avoid strenuous activity (e.g. tennis, jogging or long walks) during the first few weeks after the injection and begin rehabilitation activities when possible.

Can you have more than one treatment?

Whilst trials have not been conducted to show treatment effect, future treatments with Arthrosamid® are not contraindicated and can be discussed with your consultant.  

Can I receive Arthrosamid® treatment in both my knees?

Yes, it is possible to have both knees treated with Arthrosamid®, but your consultant is best placed to decide the time period before the treatments.