What is a total knee replacement?
In total knee replacement, damaged surfaces at the ends of the thighbone and shinbone are removed and replaced with prosthetic components. It is generally considered when arthritis or joint damage is advanced and involves more than one part of the knee.
What is a partial knee replacement?
A partial or unicompartmental knee replacement treats only the affected part of the knee. NHS guidance describes it as an option when arthritis is limited to one half of the knee. Because less of the joint is replaced, the incision can be smaller and recovery may be shorter for suitable patients.
What determines eligibility for a partial replacement?
- ✓Arthritis is sufficiently limited to one compartment
- ✓The remaining compartments are suitable for preservation
- ✓Ligament stability and knee mechanics are appropriate
- ✓Deformity and range of motion are compatible with the procedure
- ✓Symptoms and imaging match the compartment being treated
Why not choose partial replacement simply because it is smaller?
A smaller operation is useful only when it treats the actual disease. If arthritis is widespread, preserving other damaged compartments can leave symptoms behind or lead to further surgery. The decision should follow standing X-rays, examination and discussion of the patient’s activity goals.
What should patients compare?
- ✓Which compartments of my knee are damaged?
- ✓Are my ligaments and alignment suitable for partial replacement?
- ✓What is the chance that another compartment may need treatment later?
- ✓How will rehabilitation differ in my case?
- ✓Would a total replacement better match the extent of my arthritis?
Frequently asked questions
Is partial knee replacement always better because it preserves more bone?
No. Preserving more of the knee can be valuable in a properly selected patient, but partial replacement is not appropriate when disease is too widespread or the knee does not meet the required mechanical criteria.
Can a partial knee replacement later be converted to a total replacement?
Revision to a total knee replacement can be considered if disease progresses or the partial replacement fails, but the complexity depends on the individual situation.
Independent patient-information sources
These sources are provided so patients can read the underlying independent guidance. External guidance is general and does not replace advice from the treating team.