Why a Partial Knee Replacement Might be the Best Choice if you have Osteoarthritis

If you have severe osteoarthritis, you may be eligible for knee replacement surgery. Surgeons routinely perform both total and partial knee replacements, but what is the difference and which might be the best choice for you?

The difference between a partial and a total knee replacement

Essentially, whether you are offered a total or a partial knee replacement depends on the extent of your osteoarthritis and which part of your knee is affected. Within your knee there are three compartments called the medial (inside), lateral (outside) and patellofemoral (front). In some patients, only one compartment of the knee is affected.

A partial knee replacement replaces only the affected compartment with a prosthetic implant, leaving more of your natural knee structure intact. By contrast, a total knee replacement replaces all of the knee joint and also removes the anterior and posterior cruciate ligaments. Partial knee replacement surgery is less invasive and tends to have faster recovery times, less pain and fewer complications.

Revision knee replacement surgery may be needed to replace a knee implant (either partial or total) that has become loose or worn over time.

Knee replacement surgery is becoming increasingly common with more than 300,000 knee replacement procedures in the UK between 2015 and 2017. However, despite the fact that up to half of people referred for surgery could be eligible for partial knee replacement, fewer than 9% are partial.

Research into partial knee replacements

If you are a suitable candidate for a partial knee replacement, recent research suggests it could be the best choice. A study published in October 2019 concluded that there is little difference between partial and total knee replacements when it comes to relieving pain and improving function of the knee. In some patients who have damage on only one side of the knee joint (referred to as uni-compartmentmental osteoarthritis) there can be a choice of undergoing either a partial or a total knee replacement. National guidelines do not recommend one approach over the other so researchers set out to gather data from the National Joint Registry for England and Wales that could provide greater clarity and inform practice.

Researchers used data from the registry collected between 2003 and 2012. They used propensity scoring to match patients who would have been eligible for either procedure, giving a total of 75,996 total knee replacements and 25,334 partial knee replacements. The study found that, while partial knee replacements led to more revision surgery, quality of life was estimated to be better both before and after the revision procedure compared to total knee replacements. Partial knee replacements were also found to be more cost-effective.

The study concluded that partial knee replacements for appropriate patients, carried out by qualified and experienced surgeons, represent the best use of NHS resources. Researchers also point to newer techniques, such as the use of uncemented components, which could improve patient outcomes.

The TOPKAT study, which has been published in the Lancet and widely reported in newspapers such as Guardian, Mail and Telegraph, gives further comparison about total versus partial knee replacement for those people suffering with medial compartment osteoarthritis.

Benefits of partial knee replacement

If you are eligible for partial knee replacement, your surgeon will discuss the likely benefits and risks with you to enable you to make an informed decision. In general, the advantages of this type of surgery are compelling – less blood loss, fewer complications, retention of more of your own natural bone and soft tissue, faster recovery times and better range of motion.

On the downside, there is a slightly higher chance that you will need revision surgery if you have a partial knee replacement. Revision surgery can be more complicated than primary knee replacement and you may not have such good function of the knee joint afterwards than you would after a total knee replacement.

If you have severe osteoarthritis of the knee and believe you may be eligible for knee replacement surgery talk to us for individual advice on your options.