Osteoarthritis is progressive damage of the cartilage that cushions the ends of your bones. The cartilage wears away so that bone rubs against bone, causing inflammation and pain.

Knee osteoarthritis is a common condition that affects the knee joints, causing pain and stiffness that can affect your ability to walk and exercise.

Synovitis, or synovial pain, is a common symptom of knee osteoarthritis. It’s caused by inflammation of the synovial tissue, which is the lining of the knee joint. Synovitis is also associated with a more rapid loss of cartilage if you already have osteoarthritis.

Treating synovitis in the early stages of osteoarthritis may slow down its progression [2].

There are several reasons you might choose to have an Arthrosamid® injection:

• Painkillers and lifestyle modifications haven’t eased your knee pain
• Knee replacement surgery may not be right for you; you may be too young or have a medical condition which prevents you from having surgery
• You may not want a knee replacement, for example if you work in a job where you’re kneeling regularly

Your clinician will review your medical history, including your level of pain. They may arrange an x-ray to establish the grade of osteoarthritis and will discuss your options at your appointment.

Your Consultant will discuss your suitability for Arthrosamid® treatment at your initial consultation and any reasons why you might not be able to have the procedure. These include:

• If you have an infection on or near the injection site
• If you have haemophilia or take anticoagulants
• If you have an autoimmune condition, such as Multiple Sclerosis, Addison’s, or Coeliac Disease
• If you’re had a knee arthroscopy in the past six months
• If you have a foreign body in your knee
• If you’re pregnant or breastfeeding
• If your diabetes is poorly controlled
• If you’re planning to have major dental work

• One treatment, performed in a single ACU appointment under local anaesthesia – no surgery required
• Longer-lasting relief from pain compared to other injectables for knee pain

It’s possible to have Arthrosamid® injections in both knees, but you should discuss this with your Consultant.

Clinical trials have reported no serious side effects following an Arthrosamid® injection [3,4].

Arthrosamid® isn’t currently available on the NHS.

Your Consultant will give you an oral antibiotic one to two hours before the procedure to reduce the risk of infection.

They’ll swab the area and use a local anaesthetic to numb the skin around the injection site. Next, they’ll insert the needle with the first syringe of Arthrosamid® into your knee’s synovial cavity, using ultrasound to guide them. You may notice that the sensation is different as the gel is thicker than most other injectables.

The needle will stay in place, and your Consultant will inject five further doses of Arthrosamid® gel. The Arthrosamid® will disperse within the synovial fluid and start to bind with the synovial tissue [5].

Your Consultant will remove the needle, swab your knee, and cover the wound with a plaster.

Treatment usually takes between 20 and 30 minutes.

Immediately after the Arthrosamid® injection, we’ll invite you to rest until you feel ready to walk again. Your knee might feel a little uncomfortable as the anaesthetic wears off.

You might experience joint pain and a sensation of swelling in the joint, but this shouldn’t last more than a couple of weeks. If your knee becomes red, hot, very swollen, or more painful, please contact your Consultant immediately.

Arthrosamid® may take between four weeks and three months to work. However, the relief will be longer term than a steroid or hyaluronic acid injection – typically up to three years [6,7].

Your Consultant will discuss your rehabilitation programme with you. This may include further physiotherapy.

You shouldn’t drive for 24 hours after your injection, so please arrange a lift home.

You should keep moving after your Arthrosamid® injection, but we’d recommend that you take it easy to begin with and avoid any high impact activities. You should be able to return to your normal activity within three months.

Patients who are under 70 reported almost an 80% positive response rate following treatment with Arthrosamid®.

Your injection should last around three years [6,7], but there’s no reason you couldn’t have another injection after this time if your knee pain has returned. You should discuss this with your Consultant or GP.