Who needs a knee replacement?

As we get older, our bodies suffer wear and tear, and many people may find their knees suffering due to arthritis or injury. Eventually, this can become so problematic that the best option is to replace the knee. But what exactly is a knee replacement? Who needs one? Are there different types of knee replacement and what are the alternatives? Expert consultant orthopaedic surgeon Mr John Targett provides the answers.

Who needs a knee replacement?

A knee replacement is an operation to replace the surface of a knee which has been damaged by arthritis or injury. The knee replacement makes the joint more comfortable and improves the joint function.

In a primary knee replacement only the surface of the damaged joint is replaced. There are three compartments in the knee and each of these need to be treated in a total knee replacement operation. When the knee is replaced it is possible to correct deformities such as ‘bow-leg’ and ‘knock-knee’ alignments. Once the knee has been replaced, the life-span of the new knee is typically 15-20 years, assuming there are no complications of surgery.

What is a partial knee replacement and how is it different from a total knee replacement?

A partial knee replacement is used to replace the surface of only one compartment of the knee. As an example, if the inner (medial) compartment is damaged then this can be treated by a medial unicompartmental replacement. The advantage of the partial replacement is that the rest of the joint remains as the natural knee and the overall knee function is better; in particular, knee flexibility is better in most cases. The option of a partial knee replacement can be considered in 25-40% of patients needing a knee replacement.

How much can you walk after a knee replacement?

Following a knee replacement, it is possible to walk straight away, although it is difficult to walk far until the wound has healed well. Following surgery, most patients are walking well by six weeks and they continue to improve up to six months. At six months, most patients are walking unaided and confidently, including climbing hills and stairs. The full capabilities for walking vary according to the general fitness, body mass and balance of the individuals. Patients who have a partial knee replacement often walk quicker and better than those with a total knee replacement.

What are the alternatives to a knee replacement?

There are alternatives to knee replacement where a patient has arthritis. Depending on the severity of the joint damage, it may be possible to gain significant relief with knee injections.  There are two main types of injection. The first is a standard steroid injection which lasts for six weeks and may give significant benefit in the short term. The longer acting ‘lubricant-type’ injection of hyaluronic acid may give much longer relief than a steroid injection, but does not work in every case. Other options to ease pain from an arthritic knee include soft-soled shoes (with insoles in some cases), walking aids and pain-killer medications such as paracetamol or anti-inflammatory drugs. Supplements such as glucosamine and turmeric give some patients significant benefit.

The choices to be made in treating a painful damaged knee should be tailored to the specific needs of the patient, given the wide variety of symptoms and requirements for each patient. In most cases it is possible to agree a good solution to the problem and, with the excellent outcomes from surgery to replace the knee, it is important to agree with your surgeon when is the optimal time for surgery or other treatments.