Knee Replacement Surgery

Knee replacement is a common operation that an orthopaedic surgeon will perform to replace the worn or damaged knee surfaces with an artificial joint. Both partial knee replacements (PKR) and total knee replacements (TKR) are common and vary based on individual considerations. The most common reason for undergoing a knee replacement is osteoarthritis (OA). OA is a common and potentially debilitating condition. In the end stages of OA, knee replacements are the mainstay of treatment and are effective in many cases ⁽¹⁾. The aim of knee replacement surgery is the long-term relief of pain and restoring function.

Usually, your GP or physiotherapist will consider sending you for an orthopaedic examination if you have already exhausted other non-operative pathways. This includes extensive physiotherapy, painkillers, walking aids and injections. A clinician will also consider the nature of your pain and function before making the decision to refer you to an orthopaedic surgeon. They will make this decision in light of whether the pain is affecting your quality of life, mental wellbeing and sleep.

It is reported that 99% of knee replacements are due to osteoarthritis. Other less common conditions include rheumatoid arthritis or other similar inflammatory arthritis, severe trauma to the knee bones, bone death due to abrupt loss of blood supply to them, gout, haemophilia and knee deformation ⁽²⁾.

In 2017, there were 106,334 knee replacement procedures carried out in England, Wales and Northern Ireland. The average age of patients undergoing this surgery was 69 years ⁽⁴⁾. The incidence between gender is evenly split but is slightly higher in women at 56% ⁽²⁾.

Musculoskeletal physiotherapists and other appropriately qualified healthcare professionals can provide you with a diagnosis by obtaining a detailed history of your symptoms. A series of physical tests might be performed as part of your assessment to rule out other potentially involved structures and gain a greater understanding of your physical abilities to help facilitate an accurate working diagnosis.

Your treating clinician will want to know how your condition affects you day-to-day so that treatment can be tailored to your needs and personalised goals can be established. Intermittent reassessment will ascertain if you are making progress towards your goals and will allow appropriate adjustments to your treatment to be made. Imaging studies like MRI or ultrasound scans are usually not required to achieve a working diagnosis but in unusual presentations, they may be warranted.

A knee replacement will be considered based on the individual circumstances of each person. It is a major surgery so it is normally only recommended if other treatments, such as physiotherapy or steroid injections, have not reduced pain or improved mobility.

You may be offered knee replacement surgery if:

• You have severe pain, swelling and stiffness in your knee joint and your mobility is reduced.
• Your knee pain is so severe that it interferes with your quality of life and sleep.
• Everyday tasks, such as shopping or getting out of the bath, are difficult or impossible.
• You are feeling depressed because of the pain and lack of mobility.
• You cannot work or have a social life.
• You have exhausted all other treatment options.

You will also need to be well enough to cope with both a major operation and the rehabilitation afterwards.

Before your knee replacement takes place, you will undergo pre-operative physiotherapy. Exercise promoting strength and flexibility of the knee can improve the outcome of the replacement. In a review of the literature, it was found that patients undergoing knee replacements had significant improvements in function, quadriceps strength and length of hospital stay ⁽⁵⁾.

Most people return home within 3-5 days. Upon returning home, you may feel extremely tired at first and the tissues surrounding your new knee will take time to heal. Follow the advice of the surgical team and call your GP if you have any worries or queries. You may be eligible for up to 6 weeks of home help and there may be aids that can help you. You may also want to arrange for someone to help you for a week or so.

Post-operative wound healing is critical to the outcome of a knee replacement. Therefore, it is vital to keep the wound clean and dry during this time. Each surgeon will have different protocols in managing wounds, so it is important to find out the surgeon’s specific wound care protocols.

The exercises your musculoskeletal physiotherapist gives you are an important part of your recovery. It is essential you continue with them once you are at home. Your rehabilitation will be monitored by a physiotherapist. Most people can manage without walking aids after 6 weeks (about 1½ months) but it is important that you adhere to the prescribed home exercises during this time. Most hospitals will give you an advice leaflet which contains all home exercises. You may also be referred to an outpatient department to see a physiotherapist where they will progress walking and other exercises. You can start driving after 6-8 weeks. Full recovery can take up to 2 years and a small number of people experience pain after 2 years.

For patients wanting to return to physically demanding activities or sport, we would encourage a consultation with a physiotherapist as you will require further progression beyond the advanced rehabilitation stage. There is no restriction once you recover from your knee replacement, which can take up to 2 years. Many people do not feel comfortable kneeling for more than brief periods but any form of sport that does not cause significant pain or swelling is permitted.

As part of a multi-modal treatment approach, your musculoskeletal physiotherapist may also use a variety of other pain-relieving treatments to support symptom relief and recovery. Whilst recovering you might benefit from a further assessment to ensure you are making progress and establish the appropriate progression of treatment. Ongoing support and advice will allow you to self-manage and prevent future reoccurrence.

A knee replacement is only considered if all other treatment options are exhausted. These treatments include:

• Intensive physiotherapy programme.
• Lifestyle changes – including weight loss and smoking cessation.
• Steroid injections.

There are other types of surgery which are an alternative to knee replacement but results are often not as good in the long term. Your doctor will discuss the best treatment option with you. Other types of surgery may include:

• Arthroscopic washout and debridement – a tiny telescope (arthroscope) is inserted into the knee, which is then washed out with saline to clear any bits of bone or cartilage.
• Osteotomy – the surgeon cuts the shin bone and realigns it so that your weight is no longer carried by the damaged part of the knee.
• Mosaicplasty – a keyhole operation that involves transferring plugs of hard cartilage, together with some underlying bone from another part of your knee, to repair the damaged surface.

https://www.nhs.uk/conditions/knee-replacement/
Arthritis Research UK information booklet – click here.