Crashed to the ground after slipping on follow through bowling on a wet wicket and outfield. The knee was so badly destroyed that, at that time, it could not be repaired. Was asked to take up umpiring when it got as good as it could and have done so ever since.
Played indoor cricket much later because I found in the confined space you only needed to run in one direction and not very far so no twisting of the knee involved. I was big enough, and still am, to run straight over the top of anyone who got in my way as a few very fit and younger top grade cricketers found out.