Partial Knee Replacement: Benefits, Downsides and Who It Suits

How does a partial knee replacement differ from a total knee replacement?

Your knee has three compartments: the inner, or medial, compartment; the outer, or lateral, compartment; and the patellofemoral compartment behind your kneecap. In about half of knees with arthritis, only one compartment is affected.

A partial knee replacement resurfaces only the worn compartment. Your ligaments and the compartments that are not affected by arthritis are left alone. The operation is smaller than a total knee replacement and involves less blood loss.

About one in ten people are not satisfied after a total knee replacement. Dissatisfaction appears to be lower after a well-performed partial knee replacement, possibly because the ligaments are preserved and the knee moves more like a natural knee.

What is the recovery like after a partial knee replacement?

The early recovery is often quicker and less painful than after a total knee replacement. Many people go home one to three days after surgery. By about six weeks, many people have regained most of their movement, no longer need strong pain relief and can walk without crutches. Recovery varies from person to person.

The early advantage may not last. One randomised trial found better pain and activity scores two months after partial replacement, but the differences largely disappeared by two years. The TOPKAT trial found no clinically meaningful difference in pain and function at ten years. These trials are discussed in Partial or Total Knee Replacement: Which Is Right for You?.

After recovery, many people return to low-impact activities such as cycling, hiking, golf, swimming and tennis. Studies report return-to-activity rates of 80–98%, and people who have a partial replacement are more likely to return to sport than those who have a total replacement. Your own result will depend on your knee, your fitness and your goals.

Why does surgeon experience matter?

The 2025 Australian joint replacement registry annual report estimates a ten-year revision rate of 11.3% for partial knee replacement, compared with 4.7% for total knee replacement. In other words, about 11 in 100 partial knee replacements need further surgery within ten years.

These figures are averages across all surgeons and patients in Australia, rather than a prediction for your knee. Surgeons who are trained in partial knee replacement and perform it regularly have lower revision rates than those who do not. A commonly cited benchmark is that at least 20% of a surgeon’s knee replacements should be partial replacements.

During his training in the United Kingdom, Dr Vishal Pai learned to perform conventional partial knee replacement using the uncemented Oxford implant, one of the most widely used partial knee implants worldwide. He subsequently trained in robotic-assisted partial knee replacement.

Can robotic assistance lower the revision rate?

Robotic assistance can improve the alignment of a partial knee replacement compared with conventional methods. Early results suggest robotic-assisted partial knee replacements have a lower revision rate, as shown in data from the Australian joint replacement registry.

These are early, short-term results. Dr Vishal Pai uses Mako robotic assistance with the fixed-bearing Stryker Restoris MCK implant. Robotic assistance cannot guarantee that arthritis will not progress or that further surgery will never be needed.

What are the downsides of a partial knee replacement?

Arthritis can progress to involve other compartments of your knee, causing pain in a different location. If this happens, the partial knee replacement may need to be revised to a total knee replacement. This is usually possible, although it can be more complex than a first total knee replacement.

As with any knee replacement, risks include infection, blood clots, stiffness and persistent pain.

Are you a suitable candidate for a partial knee replacement?

A partial knee replacement may be suitable if arthritis affects only one compartment of your knee and you do not have a significant deformity or stiffness. Your symptoms should also justify surgery after non-surgical options, such as exercise, physiotherapy, weight management and pain relief, have been tried.

People with rheumatoid arthritis or other inflammatory types of arthritis are generally not suitable, because the arthritis may affect all parts of the knee and cause the partial replacement to fail.

Dr Vishal Pai will arrange a focused series of knee X-rays as well as X-rays from your hip to your ankle, called long-limb alignment views. These show which compartments are affected by arthritis and the overall alignment of your leg. If it is unclear whether other compartments are affected, he will arrange an MRI scan of your knee.

What happens before and after surgery?

A knee replacement is a major elective operation, so it is important to reduce any medical risks beforehand. You will be referred to Dr Vishal Pai’s perioperative physician before surgery so that any medical conditions can be optimised.

During the operation, the anaesthetist will give you a combination of pain relief. Dr Vishal Pai also injects a combination of local anaesthetic, an anti-inflammatory, morphine and a steroid around the knee to help with your comfort after surgery. A partial knee replacement takes about one to one and a half hours.

You can expect to stay in hospital for one to three days. After you go home, you will need outpatient physiotherapy. Dr Vishal Pai works closely with local physiotherapists to monitor your rehabilitation.