Knee Distraction

Joint distraction uses the body’s natural healing processes to repair damaged cartilage in the knee. During minimally invasive joint preservation surgery, the bones are gently pulled apart to create space and are fixed using pins and an external frame.

It can help younger patients with osteoarthritis who, because of their age, aren’t suitable to have knee joint replacement.

Scientific studies have also shown that knee joint distraction is a very effective treatment for younger patients with osteoarthritis.

What conditions can be treated?

It can treat osteoarthritis of the knee. It can’t be used to treat patellofemoral arthritis (behind the kneecap).

What can I do to prepare for my knee distraction surgery?

Research carried out by the World Health Organization demonstrated that patients who have the knowledge, skills and confidence to manage their own condition enjoy better outcomes.

It’s important to feel well informed about your treatment and to carry out any exercises you’ve been given to do before and after surgery. The activities that are suggested before treatment include strengthening the muscles around the knee joint and improving your balance. This is important because, during the 6 weeks that the frame is in place, your leg will be in a straightened position and muscles can weaken. You may also find it more difficult to balance.

A member of our physiotherapy team will advise you about the kind of exercises that can help.

What happens at my pre-surgery appointment?

We’ll discuss your treatment options with you so that you can decide if it’s right for you. We’ll give you some detailed information about the treatment and your rehabilitation afterwards. You may have:

  • X-rays to check for osteoarthritis in your knee
  • An MRI scan to assess any damage to your cartilage
  • A DEXA scan to check your bone density. If you have low bone density, knee distraction may not be the right procedure for you
  • Blood tests, including checking your Vitamin D levels (vitamin D is important for bone and joint health)

As well as being weighed, we’ll carry out some pre-operative tests to check on your general health. There’ll be an opportunity to discuss your medical history and any risks of surgery that might affect you.

We’ll discuss the risks and complications of treatment with you so that you can sign an informed consent form.

If you decide to go ahead, it’s important to follow the preparation advice from your healthcare team. This includes:

    • If you smoke, you should stop at least 8 weeks before the operation and not restart for at least 3 months afterwards. This is because the toxins in smoke can affect your body’s ability to heal. It can also raise the risk of complications including blood clots in the lungs (pulmonary embolism) or calf (deep vein thrombosis). Smoking also increases your risk of having an infection
    • Taking advice about any medication you’ve been prescribed and whether it should be taken during the week before your surgery, the day of surgery and the first few days afterwards. This is particularly important if you are taking blood-thinning drugs such as warfarin which can increase bleeding during surgery
    • Following any instructions you’ve been given about fasting (including drinking) before your operation. This is to avoid problems associated with the general anaesthetic, such as nausea
    • We will be able to advise you about the level of activity you can safely do while you are waiting for surgery

What type of anaesthetic will I need?

Most people have a general anaesthetic or, in some cases, a spinal anaesthetic (epidural). We’ll discuss this with you during your pre-operative appointment.

How long will I be in the hospital?

The procedure takes around an hour. In most cases, you’ll be in the hospital for about 2 to 4 days afterwards.

What does knee distraction surgery involve?

  • During minimally invasive surgery, an external frame is fixed across the joint. The frame has two (adjustable) tubes
  • The surgeon connects the frame to the knee joint using pins that go through the bones and skin, leaving tiny wounds on the surface
  • The surgeon distracts (pulls apart) the bones of the knee joint by 2mm
  • Your knee will be in a fixed, extended (straightened) position

What will happen immediately afterwards?

Once you have returned to the ward, you’ll be encouraged to get up and move around from time to time. This improves blood flow and reduces the risk of deep vein thrombosis (DVT). You’ll be helped to use crutches and walk with your knee straightened in the fame. We’ll also explain how to take care of your skin around the pin wounds.

Over the next few days, you’ll be shown how to adjust the frame to distract the knee joint an extra 1 mm each day until you reach 5 mm three days after your surgery. This will be closely monitored by your surgeon. We’ll help you begin weight-bearing on your knee, using your crutches, and one of our physios will help you to gradually increase the distance you can walk with the frame. A spring mechanism in the tube acts as a shock absorber. This helps you to walk comfortably while the joint is being distracted.

What about pain relief?

Most people don’t find knee distraction surgery to be a very painful procedure. During your operation, you’ll be given an injection of pain relief around the knee. Afterwards, you’ll be given painkillers as required. Any pain is usually from the pin sites rather than from the distraction in the joint. You’ll be able to take over-the-counter painkillers as advised by your doctor when you return home.

Are there any complications after surgery?

The risk of complications is low but can include:

  • Bleeding, or infection in the pin wounds
  • Blood clots – you’ll be given blood-thinning medicine to help prevent these

Before you go home, you’ll be shown how to keep the wounds clean. You’ll also be given antibiotics during surgery to help reduce the risk of infection. You should contact us, or your own GP straight away if:

  • You have pain that becomes worse – lasting for more than a few days – in the knee joint
  • You have a temperature and/or feel unwell – this could mean you have an infection
  • Your knee joint is very inflamed, swollen, or the wound is bleeding/oozing
  • You have extreme discomfort in your lower leg (this can be a sign of DVT)

When can I put weight on the joint?

After your surgery, we’ll show you how to walk with crutches, putting some weight on the knee. You’ll also be shown some exercises to build up your strength and balance while your leg is immobilised in the frame. We’ll be able to advise you about how to increase your activities, and what you can and can’t do.

How long is the recovery?

  • It can take 3-5 days to walk comfortably with the frame, using crutches
  • The frame remains in place for about 6 weeks
  • It’s removed while you’re under a general anaesthetic and you’ll be able to go home the same day
  • One of our physiotherapists will be able to advise you about progressive weight-bearing and walking exercises to help you bear your full weight during the next 2 weeks (around 8 weeks after surgery)

How long will I need off work?

That depends on the kind of work you do. If you don’t need to spend much time standing up and you can work using crutches (for example, at a desk in an office) you can usually return to work about a week after your surgery. However, if your job involves manual work, you may need up to two months off.

When can I drive again?

Most people can drive around 2 weeks after the frame has been removed (7-8 weeks after surgery).

Although your surgeon can advise you about when it’s safe to start driving again, it’s your own responsibility to drive safely. You should also check with your vehicle insurer to confirm you are covered.

How can I help improve/speed up my recovery?

The best way to improve your rehabilitation is to begin building up your muscle strength and balance before your surgery. Afterwards, follow any advice from your physiotherapist about gradually building up your exercise levels so you can get back to normal as soon as possible.

What is the long-term outlook?

Based on the clinical results of high-level scientific research, the procedure gives immediate pain reduction which can last more than 5 years.

  1. Kings Fund. Supporting People to manage their health. Available at: Accessed 22 November 2016.


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