Knee preservation surgery: when is it suitable and what is involved?

If you have knee osteoarthritis, you may reach the point of needing surgery to relieve your knee pain. Knee preservation surgery focuses on maintaining your native knee tissues for as long as possible so that you can avoid having knee replacement surgery.

What is involved in knee preservation surgery?

Knee preservation surgery involves a procedure called an osteotomy, where the shape of the leg is changed so that your knee joint can be realigned. This realignment aims to reduce the load and pressure placed on the diseased, or painful, part of your knee joint. By moving the load onto a healthier part of your knee, you can find relief from your symptoms.

While an osteotomy is the main part of knee preservation surgery, other surgical elements can be also required, such as reconstructing or repairing your knee ligaments and improving the function of your meniscus, a C-shaped piece of cartilage that sits between the bones of your knee joint and acts as a shock absorber. The meniscus can be repaired, via keyhole surgery, or replaced with a transplant, where meniscal tissue is taken from a donor to substitute your damaged and unrepairable meniscus. 

Knee preservation surgery may also involve cartilage regeneration surgery to stimulate the production of new cartilage to cover the ends of the bones that make up your knee joint. This can help replace cartilage lost through osteoarthritis.

Preservation versus replacement

If you have knee osteoarthritis that can’t be effectively managed medically and it’s reducing your quality of life, your doctor may recommend knee replacement surgery. Although knee replacement surgery has a high success rate, it currently cannot fully replicate the mechanics of your natural knee. Often those who have had a total knee replacement can’t engage in dynamic activities, such as jumping [and in some cases] running.

Consequently, if you’re younger or want to lead a more physically active life (eg play dynamic sports), your doctor may recommend knee preservation surgery. By preserving your knee tissues, you can benefit from the natural mechanics of your knee and obtain greater function than if you had your knee replaced. 

However, as with any surgery, you will need a thorough assessment first to determine if knee preservation surgery is suitable in your case. Your doctor will ask you about your symptoms and functional limitations; examine your knee and perform investigations such as X-rays and an MRI scan. The shape of your leg will also be assessed to help determine if an osteotomy can effectively realign your knee.

If knee preservation surgery is suitable, it will be carefully planned out and may take one or two operations to complete. 

Risks of knee preservation surgery

As with any surgery, there is always the risk of bleeding, blood clots in the legs or lungs, infections, nerve damage and damage to other tissues. 

However, knee preservation surgery also comes with the risk of stiffness due to the formation of scar tissue. You will, therefore, need significant rehabilitation and physiotherapy after surgery to reduce this risk.

In around 15% of cases, further surgery is needed after the initial knee preservation surgery. There are many reasons for this including to resolve stiffness, assess re-injury or address parts of the surgery that may not have been successful eg a failed meniscus repair.   

Recovering from knee preservation surgery

After a knee replacement, you're allowed to walk on your leg fully and bend it as much as you can — there are few restrictions post-operatively.

However, after knee preservation surgery you are often limited in the amount of weight you can place through the knee (via crutches) and sometimes the amount you can bend the knee (via a knee brace). This is in order to protect the surgery performed and allow healing to begin before loading occurs. 

From around six to eight weeks post-surgery, you will start placing weight on your knee and building up to your usual activities. It will take around four to six months after your surgery to regain good function of your knee and you won’t be able to return to more dynamic activities (eg running, jumping) until around six months post-surgery. 

Although after six months you can place greater strain on your knee, you will likely find that your knee muscles are still not strong. You will, therefore, need to gradually build up your knee strength as well as your own confidence. 

It can often take a year or so before your knee feels strong enough to confidently take part in sports and other physical activities that place your knee under significant strain. 

Long-term outcomes

Around 80-90% of individuals who have knee preservation surgery don’t need knee replacement surgery within 10 years. In the UK, these outcomes are tracked by the UK Knee Osteotomy Register. 

Factors that affect the likelihood of eventually needing knee replacement surgery include the type of knee preservation surgery, body weight, your general health and age.