A conversation with the dentist.
Dentist, "Mr. Johnson, you have 3 teeth that have severe decay and we need to extract them. I am most comfortable with dentures rather than implants. I am going to extract all your teeth and give you some really great dentures that should last 20 years."
Mr. Johnson. "Doctor, is that really necessary.... can't you just replace the damaged ones"
This conversation sounds very amusing but the analogue is happening thousands of times every day in the US on the topic of knee replacement. Many surgeons are not comfortable with all the biological and less invasive treatments for arthritis. If a knee has arthritis in one part, the reflex response is to replace the whole knee. Total knee replacement is great but there are issues with it for the younger and more active patient. It should be reserved for the most severe cases with arthritis involving at least two out of three of the knee compartments. If you do not have arthritis in all three compartments, then simply ask your doctor about biological joint replacement or partial knee replacement. If they want to only do a total knee replacement, it may be worthwhile to get some other opinions.
Here is a review on the topic. It is a bit dated since it does not discuss robotic partial knee replacement which is a major advance.