If your talking about needing another knee replacement in your 50's if you do it now that means your 40-ish. Knee replacements last approximately 15 years depending on how hard you use them. Since your on a ski blog I assume you want to keep skiing, something dr's don't typically recommend after TKR.
Since your close to Canada there may be another option, stem cell therapy. Insurance won't cover the cost. In the US it will be about $8000, no idea of what the cost would be in Canada. There are two methods, both use your own stem cells. One uses stem cells taken from bone marrow in the pelvis. The other uses stem cells taken from fat tissue around the abdomen. This second method requires a Plastic Surgeon because it uses lipo suction to harvest the stem cells. A lot of Plastics guys have gotten in on the "regenerative medicine" market. Knees are a speciality. Hyaluronic acid and stem cells mix so both can be used simultaneously. Platelet Rich Plasma (PRP) may also be used with the stem cells. Again your own plasma. So, they're putting your own stuff back into your body.
I had it done in 2012 and it gave me 5 good years. I had trouble walking up and down stairs and had swelling every day I skied. Even now I can do stairs no problem and skiing is not an issue, no swelling. However, the pain is getting harder to control and I can't afford another stem cell treatment unless insurance will cover it. Interestingly, there are a couple of Orthopedic clinics in this area that now do stem cell therapy for knees so some of the cost may now be covered.
If I do a TKR it should last the rest of my life because I'm 72. But, I'm not willing to give up my factory parts unless it's absolutely necessary.
Do some more research. Find an Orthopedic doc that does stem cell therapy and talk to them. It usually doesn't cost to talk. See if theres a Regenerative Medicine clinic in the town close to you in Canada. If it's cost effective it might be worth a try. The good thing about stem cell thera