- Your knee is a complex joint consisting of three parts: patella (“knee cap”), tibia, and femur. Functionally, it is made of three compartments: medial, lateral, and patellofemoral compartments. As opposed to total knee replacement, partial knee replacement involves removing and replacing only one compartment. As you can see in the image, only the medial side of knee can be damaged and treated with medial partial knee replacement. Similarly, lateral part or patellofemoral part (“kneecap”) can be replaced only, preserving other compartments and all the ligaments. This type of partial knee replacement might feel more natural and its recovery is quicker compared to total knee replacement. Description text goes here

- If you are diagnosed with severe arthritis in your knee and your daily activities are severely affected due to pain, you might be a good candidate. We have to first assess whether only one compartment is affected by doing thorough examination and assessment of your xray. When you see an orthopedic provider for the first time, you will likely go through nonoperative management such as weight management, physical therapy, and/or steroid injection. We would like to try nonoperative treatments first prior to recommending partial knee replacement. Of course, there are exceptions to this. Please talk to your provider whether you are a good candidate. text goes here

- Benefits are straightforward: pain relief and functional gain. Partial knee replacement is meant to provide you pain relief and stability so that you can start enjoying weightbearing activities again!

- Risks are not common but there are many of them. Please refer to the total knee replacement section where I compiled an exhaustive list of complications associated with total knee replacement. This list can also apply to the partial knee replacement.

- Unlike total knee replacement, the partial knee replacement is associated with less infection but it does not last as long.

- I make about 8-12 cm incision in the middle of your knee and enter the joint. In “robotic” partial knee replacement, the jig system is not used. Instead, bones are cut and burred in semi-automatic fashion as I lead the robotic arm to cut through the bone in pre-defined depth and area based on your anatomy. After these bone cuts, implants are properly positioned, and soft tissues are repaired. Skin is usually repaired with absorbable sutures.

- 20-30 years or hopefully longer (granted that there is no complication associated with the surgery)

- A recent study pooling all the data in the literature demonstrates that at 25 years, 70% of partial knee survived (Reference 1).

- However, I often perform partial knee replacement using robotic technology, which results in a higher success rate. Using Mako robotic-arm technology, 98% survivorship was demonstrated at 10 year (Reference 2).

- However, partial knee replacement does not last as long as total knee replacement.

- I like the conservative approach in addressing the only diseased portion. I can preserve your ACL and other parts of your bone. Partial knee will feel more natural and recovery is faster. Furthermore, it is much easier to convert from failed partial knee to total knee than revising the total knee replacement with another total knee replacement.

- On average, it takes 60 – 90 minutes

- There are different phases of recovery. Overall, I say at least one year of complete recovery. However, we expect that you feel better than what you are feeling now at week 6.

o Phase I (Day 0 to week 2): First two weeks of recovery is quite painful! This is the time you have more pain than ever before as your body goes through the highest inflammatory phase. This is the time to rest!

o Phase II (Week 2 to 5): From week 2 to 5, you will start to walk more and start gaining range of motion and strength. For some patients who have desk jobs, they can go back to work at week 5.

o Phase III (Week 5 to Month 2.5): This is the time when you notice the biggest improvement in terms of strength, endurance, and ROM. You are gaining the confidence and start to do more daily activities before. Most of you can go back to work at month 3.

o Phase IV (Month 2.5 to Month 5): Your knee starts to feel normalized. You are gaining more endurance. You don’t have to sit down frequently. Swelling is finally going down and you are sleeping better. 90% of recovery is complete at month 6.

o Phase V (Month 5 to Year 1): Tissues are becoming more natural. You will notice less stiffness and less discomfort. You are walking much more than before. There might be days when you might not even think about having a knee replacement.

- You bet. Please check out the following incredibly useful resources.

https://orthoinfo.aaos.org/en/treatment/unicompartmental-knee-replacement/

https://www.hss.edu/conditions_partial-knee-replacement.asp

https://orthop.washington.edu/patientcare/articles/knee/unicompartmental-knee-arthroplasty.html

https://hipknee.aahks.org/full-vs-partial-knee-replacement-whats-the-difference/