Can only the damaged part of your knee be replaced?
Partial knee replacement, also known as unicompartmental knee replacement, may be considered when arthritis is limited to one compartment of the knee rather than affecting the entire joint.
During the procedure, only the damaged bone and cartilage are resurfaced with metal and medical-grade plastic components. The healthy portions of the knee, along with the supporting ligaments, are preserved wherever appropriate.
A detailed clinical examination and imaging review are essential to confirm whether the arthritis is sufficiently localised for partial knee replacement.
How is partial knee replacement performed?
The procedure is performed under anaesthesia through an incision at the front of the knee. The surgeon examines the joint to confirm that the damage is limited to one compartment and that the remaining cartilage and ligaments are suitable for preservation.
The damaged surfaces are carefully prepared and covered with appropriately sized metal components. A medical-grade plastic spacer is positioned between them to create a smooth gliding surface.
Because less of the joint is replaced, partial knee replacement generally uses a smaller incision and may allow a quicker recovery than total knee replacement in properly selected patients.
When may partial knee replacement be considered?
A complete orthopaedic assessment is required before recommending the procedure. Suitability depends on the location and severity of the arthritis, knee stability, range of movement, symptoms and response to previous treatment.
An evaluation may be considered when there is:
- Arthritis limited mainly to one knee compartment
- Pain concentrated on the inner or outer side of the knee
- Persistent pain affecting walking and everyday activities
- Limited improvement with medicines, physiotherapy or injections
- Adequate movement without severe stiffness
- Stable and functioning knee ligaments
- Healthy cartilage in the remaining areas of the joint
- X-ray evidence of isolated compartment damage
Patients with arthritis throughout the knee, inflammatory arthritis, significant stiffness or major ligament damage may be better suited to another treatment approach.
What happens after partial knee replacement?
Patients are usually encouraged to begin supported movement soon after surgery with guidance from the medical and physiotherapy teams. Walking aids may be required during the early stage of recovery.
Rehabilitation generally includes pain management, wound care, exercises to restore movement and strength, gradual increases in activity and scheduled follow-up consultations.
Recovery varies between patients, although it is commonly shorter than recovery following total knee replacement. Returning to normal activities should always follow the surgeon’s and physiotherapist’s advice.
Is partial knee replacement suitable for every patient?
Partial knee replacement is suitable only for carefully selected patients whose arthritis is confined to a specific part of the knee. Pain location, ligament stability, joint movement and imaging findings must all support the decision.
Although preserving healthy bone, cartilage and ligaments may support more natural knee movement, arthritis can later develop in the parts of the joint that were not replaced. Some patients may eventually require further surgery or conversion to a total knee replacement.
As with any operation, possible risks include infection, blood clots, stiffness, persistent discomfort, instability and implant-related complications. These should be discussed clearly before treatment is confirmed.