If I remember right, you're not a spring chicken anymore. While you've probably got several more years (even decades) of living, you don't want to be so injured that you can't even walk just to get 2-3 more years of reffing.
If you're in pain every trip down the floor, is it really worth the risk that you may be making it worse.
Still want to give to the kids? Be an evaluator. Become a coach. There's always the need for good coaches (and they do exist
)