If knee pain, stiffness or reduced mobility is affecting your everyday life, you may have started researching knee replacement surgery. One of the first things you may come across is the choice between a partial knee replacement and a total knee replacement.
Both procedures replace damaged areas of the knee with artificial components, but they are used in different circumstances. The right option depends on the extent and location of damage, the condition of the rest of your knee, your symptoms, your general health and your consultant’s assessment.
Understanding the difference between partial knee replacement vs total knee replacement can help you prepare for a more informed discussion about your treatment options.
What is a partial knee replacement?
A partial knee replacement replaces only the damaged section of the knee. It is also known as a unicompartmental knee replacement.
The knee has three main compartments:
- The medial compartment on the inner side of the knee
- The lateral compartment on the outer side of the knee
- The patellofemoral compartment between the kneecap and thigh bone
A partial knee replacement may be considered when arthritis is limited to one compartment of the knee.
The NHS explains that a partial knee replacement can be used when arthritis affects one half of the knee. Only the damaged side is replaced with artificial components. The procedure generally involves a smaller incision than a total knee replacement and the NHS states that recovery should be quicker.
However, a partial replacement is not simply a smaller version of a total knee replacement. Your knee needs to meet particular clinical criteria for this type of surgery to be considered.
What is a total knee replacement?
A total knee replacement replaces the damaged surfaces of the knee joint.
During the procedure, the lower end of the thigh bone and upper end of the shin bone are replaced with artificial components. Depending on the individual case, the back of the kneecap may also be resurfaced.
The NHS explains that knee replacement can involve replacing all or part of the knee joint, depending on the extent of damage. Knee replacement is commonly used to treat pain and stiffness associated with osteoarthritis and may be considered when other treatments have not worked and knee pain is affecting daily life.
A total knee replacement may therefore be considered when damage affects several areas of the knee or when a partial replacement would not adequately address the problem.
Partial knee replacement vs total: what is the difference?
The main difference is how much of the knee joint is replaced.
| Partial knee replacement | Total knee replacement |
| Replaces one damaged compartment | Replaces the damaged surfaces of the knee joint |
| Also called unicompartmental knee replacement | Also called total knee replacement |
| May be suitable when arthritis is limited to one compartment | May be suitable when damage affects more of the knee |
| Preserves more of the natural knee joint | Replaces more of the damaged joint surfaces |
| Usually involves a smaller operation | Usually involves a more extensive operation |
| Recovery is generally shorter Higher likelihood of revision | Recovery generally takes longer Lower likelihood of revision |
The NHS states that recovery from a partial knee replacement should generally be shorter than recovery from a total knee replacement. However, recovery varies between individuals and can depend on factors such as age and general health.
Further, NICE-cited data reported a 10-year cumulative revision probability of 12.23% for partial knee replacement, compared with 3.43% for total knee replacement.
The distinction is important because the decision should be based on the condition of your knee rather than simply choosing the procedure with the shorter recovery.
Who may be suitable for a partial knee replacement?
A partial knee replacement may be considered when:
- Arthritis is mainly limited to one compartment
- The remaining areas of the knee are sufficiently healthy
- The knee is stable
- Your symptoms are affecting everyday activities
- Non-surgical treatments have not provided enough improvement
- Your consultant considers the procedure clinically appropriate
Your consultant may assess your symptoms, examine your knee and review imaging before recommending a treatment option.
The fact that arthritis is present in only one part of the knee does not automatically mean that partial replacement is suitable. Other factors, including the condition of the rest of the knee and its stability, also need to be considered.
This is why a consultation is important when considering partial knee replacement in the UK. Your treatment plan should be based on your individual circumstances rather than a general comparison between the two procedures.
Who may be suitable for a total knee replacement?
A total knee replacement may be considered when:
- Arthritis affects more than one compartment
- Knee pain is persistent
- Stiffness is affecting movement
- Walking or everyday activities have become difficult
- Symptoms are affecting your daily life
- Other treatments have not provided sufficient improvement
The NHS explains that knee replacement may be recommended when knee pain is having a significant effect on your life and alternatives have not worked.
Before surgery is considered, your doctor may discuss non-surgical treatments with you.
The NHS outlines options that may be tried before knee replacement, including low-impact exercise, muscle strengthening, weight management where appropriate, walking aids, pain relief and steroid injections.
If these approaches do not provide enough improvement and your symptoms continue to affect your everyday life, surgery may be discussed as one possible treatment.
Is partial knee replacement better than total knee replacement?
There is no single procedure that is right for everyone.
A partial knee replacement may be appropriate when damage is limited to one compartment and the rest of the knee meets the requirements for the procedure.
A total knee replacement may be considered when damage is more widespread or when a partial replacement would not adequately address the condition of the knee.
There can be differences in recovery, the amount of natural joint preserved and the areas of the knee that are replaced. However, these differences do not mean that one procedure is universally preferable.
Your consultant should explain which procedure is appropriate for your knee, why it is being recommended and what alternatives may be available.
What happens during the assessment?
Before recommending partial or total knee replacement, your consultant will usually consider:
- Where your pain occurs
- How long you have had symptoms
- How your knee affects walking and everyday activities
- Whether pain affects your sleep
- Previous injuries or operations
- Treatments you have already tried
- Your general health
- Your expectations and activity levels
You may also have a physical examination and imaging, such as an X-ray.
Imaging can help your consultant understand the location and extent of joint damage. However, the findings need to be considered alongside your symptoms and physical examination.
If you want to understand more about the artificial components used during knee replacement, you can read our guide to Knee Implants Explained.
The type of implant used is determined by factors including your individual anatomy, joint condition and the consultant’s assessment. Transform Medical explains that knee implants are not one-size-fits-all and that the consultant considers individual factors when selecting an implant.
What is recovery like after partial knee replacement?
Recovery following partial knee replacement may be shorter than recovery following total knee replacement, but it is still a surgical procedure and recovery takes time.
You may initially need crutches or another walking aid. Physiotherapy and prescribed exercises can form an important part of rehabilitation.
The NHS states that people are helped to start walking soon after knee replacement surgery and may initially need crutches or a walking frame. It also states that full recovery can take several months or longer, although recovery from partial replacement should generally be shorter than from total replacement.
Your recovery may involve:
- Gradually increasing your walking
- Completing prescribed exercises
- Managing swelling and discomfort
- Attending follow-up appointments
- Returning to work according to your recovery and type of job
- Following advice about driving and other activities
Your healthcare team will advise you about when individual activities are appropriate.
What is recovery like after total knee replacement?
Recovery after total knee replacement can take several months or longer.
You will usually begin moving and walking with assistance after surgery. Physiotherapy forms an important part of recovery, helping you work on movement and strength.
At home, you may need to:
- Complete your prescribed exercises
- Gradually increase activity
- Manage swelling and discomfort
- Use walking aids initially
- Attend follow-up appointments
- Follow your clinical team’s advice about returning to work, driving and exercise
The NHS states that full recovery can take several months or longer and that the exact timeframe varies between patients.
It is important not to compare your recovery too closely with someone else’s. Your progress depends on your individual circumstances.
What are the risks?
Like all surgery, knee replacement carries risks.
Potential complications can include infection, blood clots, bleeding, stiffness, persistent pain and problems involving the new knee. There can also be damage to nerves, blood vessels or surrounding tissues.
The NHS provides information about complications following knee replacement, including blood clots, wound infection, damage to nerves or tissue, and ongoing problems such as stiffness, pain or instability.
The likelihood of complications varies between individuals. Your consultant should explain the risks relevant to you before you make a decision about surgery.
It is also important to understand that knee replacement aims to improve pain and function but does not recreate a natural knee. Individual results vary.
Can you choose between a partial and total knee replacement?
You can discuss your preferences with your consultant, but the recommended procedure should be based on clinical suitability.
A partial knee replacement may not be appropriate simply because it involves replacing less of the joint. Equally, a total knee replacement may not be necessary if the damage is limited and your knee is suitable for a partial procedure.
Before committing to surgery, it’s sensible to take independent medical advice, for example from your GP.
You may also want to ask your consultant:
- Which parts of my knee are damaged?
- Why are you recommending a partial or total replacement?
- Would I be suitable for a partial knee replacement?
- What are the alternatives?
- What recovery should I realistically expect?
- What activities might be restricted after surgery?
- What type of implant would be used?
- What follow-up care will I receive?
These questions can help you understand the reasoning behind your recommended treatment.
Exploring private knee replacement
If persistent knee pain is affecting your everyday life and non-surgical treatment has not provided enough improvement, you may wish to explore private knee replacement.
Transform Medical provides consultant-led private knee replacement for patients who are clinically suitable. The recommended procedure and treatment pathway depend on your consultation and pre-operative assessment.
You can find out more about the treatment pathway on the Private Knee Replacement page.
If you are considering private treatment, you can use the Price Checker to check the current cost of treatment and available finance options. The Price Checker is designed specifically for hip and knee surgery.
Final thoughts
The choice between partial knee replacement and total knee replacement depends on the condition of your knee and your individual clinical circumstances.
Partial knee replacement, also known as unicompartmental knee replacement, may be considered when arthritis is limited to one compartment and the rest of the knee is suitable for the procedure.
Total knee replacement may be considered when damage is more widespread or when partial replacement would not adequately address the problem.
A consultation with an appropriately qualified healthcare professional can help you understand your diagnosis, available treatment options and the potential benefits and risks of each approach.
Individual results vary, and all surgery carries risks.