These are not the only two knee surgeries that exist, by any stretch.

If I was talking about every single kind of knee surgery, I would have said so.

This should be the end of it, but you went on and constructed a personal attack from your faulty assumptions. I think that merrits some more "defense" on my part.

When there is a statement without an explicit quantifier, the quantifier becomes ambiguous. Assuming the all-quantifier in this case was your personal decision. Since you construct an insulting argument from this faulty and intentional assumption, I can only assume malice. If the ambiguity was a problem, you could have simple asked. Or better yet: Do what everyone else did and click the link. If you still thought, the ambiguity was an issue, you could have just pointed it out, instead of making an insult out of it.

Please don’t spread medical misinformation

Tell that to someone who actually spreads medical misinformation. Not only was my joke correct, I even provided a credible source, which is far beyond what you can expect from a comment on a shitposting community.

it’s not helpful

the information, that many knee-surgeries only work through placebo-effect is very helpful. In fact my simplified and sensational (and true) claim probably made many people click on the link, which helped spread the message even further.

Also I think it sets a good example to provide sources for all interesting claims, even if it is on a shitposting sub.