What is partial knee replacement surgery?

A partial knee replacement is also known as a uni-compartmental knee arthroplasty. It is the replacement of the inner or outer sides of the knee.


This is an alternative to total knee replacement, as damage is limited to only part or one side of the knee. It is done through a smaller incision and the recovery time is shorter in comparison to a total knee replacement.



A partial knee replacement is often recommended when there is only a minor deformity in the knee and when arthritis is contained to one side of the joint.


If the arthritis has extended to other areas, the knee may require a total knee replacement.

The surgery

Prior to surgery, your anaesthetist will discuss your options for anaesthesia.


The surgeon will make an incision at the front of the knee, then explore the three compartments to verify that the problem is in fact limited to only one compartment and that ligaments are intact. Once assessment is complete, the damaged bone and tissue are removed and replaced with plastic and metal prosthetics and attached with bone cement. The incision is then closed.

Risks and complications

The same potential risks for a total knee replacement apply to a partial replacement, but are less common.


As partial knee replacements only focus on one contained area of the knee, there may be potential for more surgery in the future if arthritis develops in the parts that have not been replaced. This procedure allows the option for a total knee replacement to be performed in the future, if needed.

Preparation and recovery

Excess body weight puts increased risk on the knee, with potential loosening of the joint during the recovery period. If a patient’s weight is greater than 90kg, weight loss precautions may be considered when preparing for the surgery.


Post-surgery, patients will generally spend between 3-4 days in hospital. A urinary catheter may be needed in the early stages of recovery until the patient is mobile. Physiotherapy is an extremely important part of the recovery process and can begin immediately after surgery, depending on the patient’s progress. Pain, stiffness and discomfort are expected during the initial stages of physiotherapy. Most patients are able to walk without assistance within 3-4 weeks after the surgery. Physiotherapy is seldom required after hospital discharge.

Our results

We welcome you to view our live reported feedback from patients who have received partial knee replacements at The Joint Studio. . To compare feedback against the broader industry average, please open the latest report on patient outcomes by the New Zealand Joint Registry.