Four signs you may need a knee replacement

Knee pain can range from uncomfortable to debilitating. At some point, you may need knee replacement surgery (arthroplasty) to replace your affected knee joint with a prosthetic one. But how do you know when that time has come?

Your age certainly has a role to play as wear and tear over the years puts you at a higher risk of needing a knee replacement. But it isn’t the only factor to consider — your genetics, lifestyle and any medical conditions or injuries you have also make a difference.

To help get a clearer idea of whether you need knee replacement surgery, look out for these four signs:

1: Reduced mobility

Osteoarthritis is the number one reason for knee replacement surgery. This condition is more common as you get older and causes pain, stiffness and swelling in your joints. This ultimately leads to reduced mobility eg you may struggle to get into a car because your knee won’t bend or find climbing stairs difficult. You may also notice your knee clicks, crunches or grates when you move — this is called crepitus.

2: Knee swelling

If you have chronic (long-term) swelling in your knee and it looks different from your other knee, see your GP. This is especially important if you also have other symptoms such as pain or reduced mobility. The condition of your knee may have reached the point where surgery is needed. 

3: Knee pain that keeps you up at night

Pain that is so severe or persistent that it stops you sleeping could be a sign that your knee isn’t working as it should. If you’ve tried treatments such as physiotherapy or steroid injections for your knee pain and it hasn’t improved then your doctor may recommend surgery.

4: Knee pain that is affecting your lifestyle

When your knee pain makes it difficult to work, socialise or pursue the activities you enjoy, then it’s time to seek treatment, especially if it’s making you feel frustrated or depressed. You should also look out for pain that consistently comes on after an activity — just because the pain goes away, it doesn’t mean it isn’t serious.

While these four signs could all be down to osteoarthritis, this isn’t the only condition that can damage your knees. Other causes of knee damage include: 

• An injury or deformity in your knee
• Avascular necrosis — death of the knee joint due to a lack of blood supply
• Bone dysplasia (unusual bone growth)
• Gout
• Haemophilia
• Rheumatoid arthritis

Getting treatment

You’ll need an X-ray to assess the damage to your knee joint. Your doctor may suggest alternative treatments before recommending knee replacement surgery eg keyhole surgery to repair damage to your knee (knee arthroscopy) — this is carried out using a thin, telescopic instrument called an arthroscope.

Other surgical treatments include: 

• Arthroscopic washout — flushing out your knee joint with a salt solution (saline) to remove loose bone or cartilage; you’ll likely be in hospital for a day and possibly the night too
• Ligament surgery — reconstructing any damaged ligaments; expect to stay spend at least one night in hospital
• Mosaicplasty — taking healthy cartilage from the edge of your knee joint and transferring it to the damaged area; you may be in hospital for up to 24 hours
• Microfracture — your surgeon makes small holes in your bones to encourage cartilage growth; you’ll likely go home on the same day as your surgery or you may have to stay one night
• Osteotomy — your shinbone is cut and realigned to reduce the weight carried by the damaged part of your knee; you’ll likely go home 48 hours after your surgery

Knee replacement surgery

When you’ve talked through your options with your doctor, together you may decide that knee replacement surgery is the best one to improve your mobility and reduce your pain. There are three types of knee replacement surgery:

Kneecap (patellofemoral) replacement 

If you have arthritis in your knee but most of your knee joint is in good shape, it may be possible to replace the back of your knee cap and the front of your thigh bone to relieve your symptoms. You’ll need physiotherapy after surgery and should make a full recovery, allowing you to return to all of your normal activities, in around 6 to 12 months.

Partial knee (unicompartmental) replacement

Where damage to your knee joint is limited to the inside of the joint, it’s possible to replace just that part of the knee instead of the whole joint. Expect to spend three or four days in hospital and to start physiotherapy after your surgery. You should be able to walk without assistance or support after three to four weeks and over the next six to eight months, you'll continue to heal and recover full function of your knee. 

Total knee replacement 

This surgery involves the longest hospital stay, usually around five days. The worn-out or damaged parts of your knee are removed and replaced with a prosthetic joint. As with the other knee surgeries discussed here, you’ll need regular physiotherapy. In most cases, you can return to most of your usual activities after three months, with the exception of high-impact sports. Complete recovery usually takes 6 to 12 months and your prosthetic joint will last 10 to 20 years. 

Knee replacement surgery is a common procedure and complications are rare. However, in some cases, it can take as long as two years to fully recover from surgery as you rebuild your muscle strength. Your new joint won’t be as flexible as a natural knee and you’ll need help around the house for the first few weeks after surgery. However, over time, you’ll achieve greater independence.