Partial Knee Replacement in Sydney

What is a partial knee replacement?

A partial knee replacement, also called a unicompartmental knee replacement, is surgery to replace only the damaged part of the knee rather than the whole joint. It is most commonly used when osteoarthritis is limited to one compartment of the knee — usually the medial compartment on the inside of the knee.

The knee has three main compartments: the medial compartment on the inside, the lateral compartment on the outside, and the patellofemoral replacement compartment behind the kneecap. If arthritis is widespread across the knee, a total knee replacement is usually more appropriate. But when the disease is genuinely limited to one area, a partial replacement may preserve more of your natural knee.

Because only one compartment is resurfaced, the operation can often be done through a smaller incision with less disruption to bone and soft tissue. For the right patient, this can mean less pain, faster early rehabilitation and a knee that may feel more natural than a total knee replacement.

Do you need a partial knee replacement?

A partial knee replacement is not simply a smaller version of a total knee replacement. It is a more selective operation, and careful patient selection is the most important factor in getting a good result.

You may be suitable if your arthritis is confined to one compartment of the knee, your knee ligaments are stable, your knee still moves reasonably well, and your symptoms are affecting day-to-day life despite good non-surgical treatment. It may not be suitable if arthritis is present in multiple compartments, the knee is very stiff, there is significant deformity, the ligaments are unstable, or you have inflammatory arthritis affecting the whole joint. In some cases, a knee osteotomy may be considered as an alternative.

At your consultation, Dr Jonathan Negus will take a detailed history, examine your knee and review imaging, usually including X-rays. The decision is not based on the X-ray alone. It depends on whether the painful, arthritic part of the knee matches your symptoms and whether the rest of the joint is healthy enough to preserve.

Benefits and risks

What you can expect it to achieve

• Relief from pain caused by arthritis in the affected compartment
• A smaller operation than total knee replacement for suitable patients
• Less bone and soft tissue disruption
• Faster early recovery and shorter hospital stay for many people
• Earlier return to walking and everyday activities
• Better preservation of normal knee movement and ligament function
• A knee that may feel more natural than a total knee replacement

Risks to understand

• Common and temporary: swelling, bruising, warmth around the knee and stiffness in the early recovery period
• Uncommon: infection, blood clots, wound problems, nerve or blood vessel injury, and fracture during implant insertion
• Specific to partial replacement: arthritis can progress in the other compartments of the knee over time
• Longer-term: the implant can loosen or wear, and some people may eventually need conversion to a total knee replacement

All knee surgery carries risk and outcomes vary between individuals. The aim of your consultation is to make sure the operation matches the problem. A partial knee replacement can work very well in the right knee, but it is not the right operation for every person with knee arthritis.

Partial knee replacement	Total knee replacement
Only one compartment is replaced	The whole knee joint surface is replaced
More natural bone and ligaments are preserved	More bone and joint surface are resurfaced
Usually smaller incision and less soft tissue disruption	Larger operation for more widespread arthritis
Often faster early recovery	Recovery is usually more gradual
Only suitable for selected patients	Suitable for advanced arthritis across the knee

The procedure: what happens

Before surgery, you will have a pre-operative assessment to review your general health, medications, imaging and anaesthetic plan. Where appropriate, we recommend pre-operative rehabilitation to improve strength around the knee before surgery.

The operation is performed under general or spinal anaesthesia. A small incision is made over the knee to expose the compartment affected by arthritis. The worn ends of the femur and tibia are carefully prepared using specialised instruments, while the healthy compartments and key ligaments are preserved.

Metal components are then placed onto the prepared bone surfaces, usually secured with bone cement. A medical-grade polyethylene spacer is inserted between the components to create a smooth gliding surface. The knee is tested for alignment, stability and movement before the incision is closed with sutures and covered with dressings.

After surgery

You will wake in the recovery room, where your pain, circulation and vital signs are monitored closely. Once you are comfortable and stable, you will return to the ward and begin your recovery. Most people are encouraged to put weight through the knee straight away, with a physiotherapist helping you stand, walk and practise safe movement.

Many patients go home after one to three days, and some suitable patients may go home on the same day. Your discharge timing depends on pain control, walking safety, home supports and your general health.

Partial knee replacement recovery and rehabilitation

Recovery after partial knee replacement is usually faster than after total knee replacement because less bone and soft tissue are disrupted. You can usually begin weight-bearing immediately, although walking may feel awkward at first and you may use crutches or a walker for a short period.

The first two weeks are focused on settling swelling, protecting the wound, restoring knee movement and walking safely. By around six weeks, many people have returned to most everyday activities, although strength, confidence and comfort continue improving for several months.

Recovery timeline

Phase	Timeframe	What to expect
Protect & settle	Days 0–14	Walking with aids as needed, wound care, swelling control, gentle range-of-motion and early strengthening
Early independence	Weeks 2–6	Walking more normally, reducing aids, building confidence with stairs and daily activities
Strength & control	Weeks 6–12	Progressive strengthening, balance, cycling, walking further and returning to most normal routines
Return to activity	Months 3–6	Gradual return to low-impact activity such as golf, swimming, cycling and longer walks
Final recovery	Months 6–12	Ongoing improvement in strength, swelling, confidence and comfort

Timeframes are a guide. Your surgeon and rehabilitation team will progress you based on your knee, your goals and your recovery.

Post-operative care

At home, the priorities are keeping the wound clean and dry, controlling swelling, taking pain medication safely, walking regularly and completing your prescribed exercises. A small amount of warmth and swelling around the knee is common in the early weeks, but increasing redness, discharge, fever or worsening calf pain should be checked urgently.

Rehabilitation at MTP Health

This is where MTP Health is different. Your rehabilitation is delivered by our own physiotherapists and exercise physiologists, working in the same clinic as your surgeon. Your plan can begin before surgery and continue seamlessly afterwards, with everyone working from the same goals and shared clinical record.

Rehabilitation focuses on restoring movement early, then rebuilding strength, balance, walking quality and confidence. Your recovery may be supported by our post-operative rehabilitation, physiotherapy and exercise physiology services.

Returning to driving, work and sport

Return to driving is usually a minimum of six weeks after right knee surgery, and around two weeks after left knee surgery in an automatic car. You must be able to safely perform an emergency stop and must no longer be taking strong pain medication. Please check with your surgeon and your insurer before driving.

Desk-based work may be possible within two to six weeks, depending on pain, swelling, transport and how long you need to sit. More physical work takes longer and should be guided by your surgeon and rehabilitation team. Low-impact activities such as walking, cycling, swimming and golf are usually introduced gradually as strength and comfort return.

Partial knee replacement cost in Sydney

The cost of partial knee replacement depends on your private health cover, hospital insurance, surgeon fees, anaesthetist fees, assistant fees, hospital charges and any excess on your policy.

If you are having surgery using private health cover, the standard fees for the surgeon, anaesthetist and assistant will usually lead to a total out-of-pocket gap of approximately $4,500–$5,000. This is the gap left after Medicare and your health fund rebates. The anaesthetist is an independent practitioner and may charge a different gap, so we provide their details and recommend checking their quote before surgery.

The surgeons at MTP Health participate in various reduced-gap schemes run by different health insurance providers. Availability can vary, and reduced-gap surgical time slots may involve a longer wait. Your insurer may also charge an excess, commonly around $500, depending on your policy.

If surgery is performed through the public system, there is no out-of-pocket surgical cost, but waiting times can be long and depend on hospital access, urgency category and local availability. For a broader overview of related fees, see our knee and hip replacement cost guide.

Why have your partial knee replacement at MTP Health

MTP Health brings together fellowship-trained orthopaedic surgeons, careful surgical planning, physiotherapy and exercise physiology in one clinic. That matters because partial knee replacement is not just about the operation — it is about selecting the right patient, preparing properly and rehabilitating well afterwards.

Honest advice comes first. If your knee is better suited to non-surgical care, we will tell you. If your arthritis is too widespread for a partial replacement, we will explain why a total knee replacement may be the safer and more durable option. If a partial replacement is suitable, we will help you understand the procedure, recovery, risks and expected outcome clearly before you decide.

Your surgeon

Frequently asked questions