Partial Knee Replacement
Overview
Partial knee replacement resurfaces only the arthritic section, or compartment, of the knee and preserves the other joint surfaces and major ligaments. It can be a useful option when pain and arthritis are genuinely confined to one area and the knee is otherwise suitable. It is not simply a smaller total knee replacement. Careful selection is essential, and robotic assistance, when used, is a surgeon-controlled planning and guidance tool rather than an independent operator.
Who may be suitable?
The most common operation is a medial partial knee replacement for arthritis confined to the inner side of the knee. A replacement of the outer or kneecap section may be considered less commonly. Symptoms, examination and weight-bearing imaging must all identify the same section as the main pain source.
The knee usually needs a functional ligament pattern, correctable deformity and acceptable movement. Inflammatory arthritis, major instability, severe stiffness or substantial disease in other compartments may favour total knee replacement or continued non-surgical care. Age alone does not determine suitability.
Potential advantages
- Preservation of more bone and ligament tissue.
- A smaller operation with less early blood loss and, for many people, faster early recovery.
- Knee movement and function may feel more natural because unaffected compartments are retained.
- Future conversion to total knee replacement remains possible if disease progresses or the implant fails.
Important limitations
- Only a minority of people with knee arthritis have the correct disease pattern.
- Arthritis may later progress in an unreplaced compartment.
- Partial knee replacements may have a higher chance of revision over time than total knee replacements in some registry groups, although early recovery and function can be favourable in carefully selected people.
- Persistent pain can occur if the pain source was not confined to the replaced compartment.
Robotic assistance
A robotic system may use a preoperative scan or measurements obtained during surgery to help plan implant position and guide bone preparation. It can provide detailed information about alignment and ligament balance.
The surgeon remains responsible for selecting suitable people, exposing the joint, preparing the bone, inserting the components and making every clinical decision. Robotic assistance does not operate independently and does not remove the risk of infection, persistent pain, stiffness, progression of arthritis or revision.
Alternatives
- Exercise, activity modification, weight management, aids, medicines and selected injections.
- Corrective bone-cutting surgery (osteotomy) for selected younger or active people with one-sided arthritis and malalignment.
- Total knee replacement when disease is more extensive.
- Continuing non-surgical care when symptoms remain acceptable.
Recovery
Walking usually begins soon after surgery with an aid as needed. Swelling, bruising and temporary sleep disturbance are expected. Rehabilitation aims to restore full straightening, bend, strength and a confident gait.
Many people progress faster in the early weeks than after total knee replacement, but recovery remains individual. Driving, work and sport depend on the operated side, strength, medicine use, wound healing and activity demands.
Risks
- Infection, bleeding, wound problems or blood clots.
- Persistent pain, stiffness, numbness or weakness.
- Fracture, implant loosening, wear or bearing problems depending on design.
- Progression of arthritis in another compartment.
- Instability or unexplained pain.
- Further surgery or conversion to total knee replacement.
Frequently asked questions
Is partial knee replacement better than total knee replacement?
Neither is universally better. Partial replacement may offer a more natural-feeling knee and faster early recovery when disease is truly isolated; total replacement is more appropriate for widespread disease.
Can I choose a partial replacement because it is smaller?
Suitability is determined by the pattern of arthritis, ligaments, deformity, movement and symptoms. Choosing it for size alone can lead to a poor result.
Does robotic assistance improve longevity?
It can assist accurate planning and execution, but longer implant survival or better symptoms are not guaranteed.
Can a partial knee be revised later?
Yes. It can often be converted to a total knee replacement, although revision is more complex than a first-time knee replacement.
General information
This page provides general information only. It cannot diagnose your condition or replace advice from a clinician who has assessed you. Your treatment and recovery plan may differ from the examples described here. Follow the instructions from your treating team. In an emergency, call 000 or attend the nearest emergency department.