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How is the knee divided?
The knee has three compartments: the inner (medial) side, the outer (lateral) side and the area behind the kneecap (patellofemoral). Osteoarthritis often begins in one compartment, most commonly the inner side, and may later spread to others. This pattern is why a partial replacement is possible for some people.
What is a partial knee replacement?
A partial knee replacement replaces only the damaged compartment and keeps the healthy cartilage, bone and ligaments, including the cruciate ligaments, in the rest of the knee. It is usually done through a smaller incision. Some people feel that the knee moves more naturally afterwards, and recovery may be quicker, although this varies.
Read more on the partial knee replacement page.
What is a total knee replacement?
A total knee replacement resurfaces the ends of the thigh bone and shin bone across the whole joint, and sometimes the back of the kneecap. It is suited to arthritis affecting more than one compartment, significant deformity or ligament damage. It is a well-established operation with long experience behind it. See the total knee replacement page for details.
Side-by-side comparison
| Feature | Partial knee replacement | Total knee replacement |
|---|---|---|
| Part replaced | One compartment only | All joint surfaces |
| Ligaments | Cruciate ligaments usually kept | One or both cruciate ligaments often removed or substituted |
| Typical suitability | Arthritis limited to one area, stable ligaments, correctable alignment | Widespread arthritis, deformity or ligament problems |
| Incision and early recovery | Often smaller; recovery may be quicker | Larger; recovery usually takes longer |
| Feel of the knee | Some people report a more natural feel | Function is often good, with a different feel for some |
| Future surgery | Arthritis may progress elsewhere; conversion to total replacement may be needed | Revision may be needed for wear, loosening or other problems |
Who may be suitable for a partial replacement?
Suitability is decided after examination and imaging. Factors that are usually considered include:
- Arthritis confined to one compartment on standing X-rays and, sometimes, specialised views or MRI.
- An intact anterior cruciate ligament (ACL) and stable collateral ligaments.
- A deformity that is mild and correctable.
- Good range of movement before surgery.
- No inflammatory arthritis, such as rheumatoid arthritis.
Age and weight alone do not always rule partial replacement in or out; your surgeon considers the whole picture. In some younger patients with one-sided arthritis, a high tibial osteotomy may also be discussed.
What are the risks of each operation?
Both operations share the general risks of joint replacement surgery: infection, blood clots, wound problems, stiffness, persistent pain and, rarely, nerve or blood vessel injury. With partial replacement, a specific concern is that arthritis may progress in the untreated parts of the knee, which may mean later conversion to a total replacement. With total replacement, recovery is often longer and some people are aware of the knee feeling different. Either type may eventually need revision surgery.
How do recovery and daily life compare?
Recovery depends on the individual, but some general patterns are seen. After a partial replacement, people may stay in hospital for a shorter time, regain bending sooner and need walking aids for less time. After a total replacement, swelling and stiffness often last longer and rehabilitation may take more effort in the early weeks. In both cases, improvement continues for months.
In daily life, both operations aim to let you walk, climb stairs and manage household tasks with less pain. Low-impact activities such as walking, swimming and cycling are commonly encouraged after either operation. High-impact sports and heavy kneeling are often discouraged, and deep squatting or sitting cross-legged on the floor may be limited for some people. Ask your surgeon what is realistic with your knee.
How is the final decision made?
Sometimes the choice is clear from X-rays and examination. In other cases the surgeon may plan a partial replacement but confirm the decision during the operation, after directly inspecting the cartilage and ligaments. If the other compartments turn out to be worn, a total replacement may be the safer choice. This possibility should be discussed and agreed with you beforehand.
The decision also reflects your priorities. Some people value a quicker early recovery; others prefer an operation that addresses the whole joint at once. Neither preference is wrong. A good decision balances the pattern of damage in your knee, your health, your goals and your understanding of the risks of each option. Our article on when knee replacement surgery is needed explains how to judge whether any replacement is appropriate yet.
Questions to discuss with your surgeon
- Which compartments of my knee are affected?
- Are my ligaments healthy enough for a partial replacement?
- What are the likely benefits and risks of each option for me?
- How might each choice affect my recovery and future surgery?
- Which activities are realistic afterwards?
Discuss your situation with Dr. Karnav Panchal to find out which type of knee replacement, if any, suits your knee.
Common questions
Is partial knee replacement better than total knee replacement?
Neither is better for everyone. Each suits a different pattern of arthritis, and the right choice depends on your examination and imaging.
Can a partial knee replacement be converted to a total later?
Yes. If arthritis progresses or problems develop, a partial replacement can usually be converted to a total knee replacement.
Can both knees be treated with different types?
Yes. Each knee is assessed separately, so one knee may suit a partial replacement and the other a total replacement.
Related treatment page: Partial Knee Replacement. To talk about your own symptoms, request a consultation.