Knee arthroplasty: a comprehensive guide

As the knee undergoes wear and tear over the years, it may need to be replaced in order to improve a patient’s quality of life. One manner of doing this is knee arthroplasty, a relatively common procedure. Revered consultant orthopaedic surgeon Mr Matthew Oliver provides a guide to the procedure, including the various types of knee replacements available on the market today.

What is knee arthroplasty and who is a candidate for this procedure?

A knee arthroplasty or total knee replacement, is an orthopaedic procedure performed when the patient's knee has worn out for whatever reason.

The most common reason is osteoarthritis of the knee where you have bone-on-bone contact and every step hurts. People opt for this procedure because they are experiencing intense, long-lasting pain. It is the treatment of choice when all conservative measures for treating osteoarthritis of the knee have been exhausted, such as painkillers, using a stick, activity modification, steroid injections, or other injection modalities.

When knee pain begins to have a significant impact on your quality of life and daily activities, it is the time to consider having a total knee replacement.

What are the different types of knee implants used in arthroplasty and how are they selected?

There are various different versions of knee replacements. Some are designed to just replace an isolated part of the knee that is worn out, such as a medial unicompartmental knee replacement. It is also possible to have that procedure performed on the lateral side of the knee as well.

One option for isolated kneecap arthritis is a patellofemoral replacement, however, it is not a commonly performed procedure.

The most common way of performing a total knee replacement in modern surgery is to cement the femoral component and the tibial component using standard instrumentation. However, the use of robot technology, computer navigation and patient-specific implants are becoming more mainstream as technology improves.

What can I expect during the recovery period after knee arthroplasty surgery?

Unfortunately, the recovery period after a total knee replacement is uncomfortable and there's no escape from this. It is a painful procedure, therefore, in the pre-operative consultation, it is paramount that the surgeon spends time warning the patient about this, because if they do not do their exercises while they're in discomfort, the knee will quickly scar up and stiffen.

The attitude to have towards the whole process is no pain, no gain, resilience and perseverance. Having said that, a key part of recovery starts before you have the operation. You need to optimise your general health, lose some weight if necessary, improve your diet and strengthen, the muscles around the knee joint with light, low-bearing exercise. This is known as 'prehabilitation'.

The term prehabilitation is key to a better outcome, therefore the fitter you are before the operation, the more rapidly you'll recover after the operation.

What are the potential risks and complications associated with knee arthroplasty?

The risks associated with knee replacement surgery are similar to hip replacement surgery, with regard to blood clots in the leg and the lung, infection, nerve injury, fracture of the bone and bleeding. It's unusual that a patient that has a knee replacement requires a blood transfusion.

Postoperative stiffness and chronic pain are risks linked to knee arthroplasty. There is certainly a small percentage of patients that come into that category and have a less than satisfactory result. Fortunately they are the exception than the rule. Again, it's about patient selection, making sure that the operation is done at the right time in that patient's life, when they're ready for it and motivated to recover. Postoperative stiffness is something that needs to be avoided at all costs.

Other risks are that the replacement can eventually wear out (aseptic loosening), and you can injure the patella tendon. Although rare, the replacement can dislocate. You can develop instability in the knee if you were to sustain an injury to it where you damage one of the natural ligaments that helps balance the knee.

That being said, on the whole, with good postoperative rehabilitation, the knee should serve you well for many, many years.

How does a how long does a knee implant typically last, and what activities should I avoid or engage in post-surgery?

A total knee replacement should last at least 15 years, if not more. There are variables along the way that can reduce the lifespan, depending on your activity levels, the risks that you take and your general health, however, with everything being equal, it is likely that the replacement would last at least 15 years or more.

There are definite health benefits from having the operation; patients must be aware that the knee may click and ache now and again, especially with increased activity. Kneeling on a knee replacement is discouraged.

It is also important to ensure that you get at least 95 to 100 degrees of flexion in your knee if you really want to get back on your bike and go cycling. Patients with knee replacements have returned to playing golf, and swimming, and some have even gone skiing, but at their own risk. It is possible to return to recreational racket sports as well. For example, some of my previous patients have returned to doubles tennis. That being said, every case is different, and everybody has their own aspirations; it just depends on what you want to achieve.

If you would like to book a consultation with Mr Oliver, do not hesitate to do so by visiting his Top Doctors profile today.