- Simply speaking, total knee replacement involves removing damaged or arthritic surfaces from femur (‘thigh bone”) and tibia (“leg or shin bone”) and replace them with artificial components such as metal and polyethylene. When both medial and lateral sides of the knee are replaced, this is called “total” knee replacement. The goal of the surgery is to provide you with a stable knee that is functional and less painful.

- If you are diagnosed with severe arthritis in your knee and your daily activities are severely affected due to pain and/or instability (“knee giving way”), you might be a good candidate. 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 total knee replacement. Of course, there are exceptions to this. Please talk to your provider whether you are a good candidate.

- Benefits are straightforward: pain relief and functional gain. Total knee replacement is meant to provide you pain relief and stability so that you can start enjoying weightbearing activities again! Even if you are noted have terrible looking xray, if you do not have pain and functional limitation, there is no benefit of the surgery. In this case, I usually do not recommend surgery.

- Risks are not common but there are many of them.

o Bleeding: can be mild (just dressing change) or rarely severe requiring reoperation

o Wound complication: wound can fail to approximate and heal properly

o Blood clot: usually asymptomatic but it can form in the leg and travels to your lung. You will be on anticoagulant and I am going to ask you to be active to prevent this

o Nerve damage: skin numbness is common around surgical area but any motor damage is very rare

o Vascular injury: exceedingly rare. If it happens, it needs immediate repair

o Ligament damage: medial collateral ligament is important for your knee stability; when it is damaged, it might require immediate repair and/or more constrained implant

o Instability: when the implant is placed too loose, you can have the sensation of knee giving way and have difficulty going up and down the stairs

o Malalignment: when the implant is tilted, it can cause pain and instability

o Stiffness: limited range of motion after the surgery which might require manipulation or reoperation

o Infection: minor infection can be easily treated with oral antibiotics but deep, severe infection requires removal of implants and IV antibiotics for at least 6 weeks

o Fracture: any break in the bone during the surgery will require immediate fixation

o Extensor mechanism disruption: disruption of either quadriceps tendon, knee cap, or patellar tendon can lead to the inability to actively extend the knee and might require further surgery

o Knee cap dislocation: very rare but patella can be dislocated

o Knee dislocation: even rarer but femur and tibia can be separated

o Polyethylene wear: Plastic material wears over time and can cause symptoms. Less of a problem nowadays with improved technology

o Osteolysis: Implant-surrounding bone can be “chewed out” in response to wear particles, potentially causing the implant failure. Very rare these days.

o Implant loosening: implant can loose its fixation and can cause pain and possibly fracture

o Implant fracture: almost never but some implants can break

o Reoperation

o Revision

o Readmission: you can be readmitted to the hospital within 90 days for various surgical and medical reasons

o Death: although very rare, death can occur due to anesthetic, medical, and surgical complications

- I make about 10-15 cm incision in the middle of your knee and enter the joint. In “manual” knee replacement, I place the jig systems and cut 5 different planes on the femur and cut 1 plane on the tibia in a systematic fashion. In “robotic” knee replacement, the jig system is not used. Instead, planes of cuts are set up digitally and executed without any guide. After these cuts, implants are properly positioned, and soft tissues are repaired. Skin is usually repaired with absorbable sutures.

- On average, it takes 60 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 6-12.

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 6): From week 2 to 6, 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 6.

o Phase III (Week 6 to Month 3): 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 3 to Month 6): 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 6 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.

- 20-35 years or even 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, 82% of TKA survived (Reference 1). This is a great news as we have developed better technology and implants recently and these advancements will likely lead to better survivorship

- There is a finite cycle that the implant can go through before it can become worn out or loose. The heavier you are, the more active you are and the younger you are, the less the implant is going to last.

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

https://hipknee.aahks.org/total-knee-replacement/

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

https://www.hss.edu/condition-list_knee-replacement.asp

https://www.mayoclinic.org/tests-procedures/knee-replacement/about/pac-20385276