Pineswipe (started as warrior):
Unconfirmed via RP, but intended to be canon
Born without foreclaws, Pineswipe wasn't expected to make it as an apprentice; he couldn't catch prey normally, he couldn't use normal fighting techniques, etc. But he found his own way of doing things, using his hind claws, his teeth, and especially, his brain, he was able to become a great apprentice, capable of anything anyone else could do.
One day, while practicing fighting, he fell and hit his back-left leg on a large rock. After that incident, he would have random, pseudo-arthritis pain in his hip every once in a while.
Canon through RP
One day (January 22, 2025) while running through Windclan to use up his excess energy, he saw a loner (Citrusscone) hunting a rabbit. Filled with loyalty and passion for his clan, he attacked the cat who was twice his size with overgrown foreclaws. Though the battle was tough, it ended in a stale-mate, where the loner kept their prey, but, as he hoped, would have second thoughts about coming back.
The fight, however, didn't leave him unscathed. After the loner fell with their whole body onto his back-left leg, he's had chronic pain in it, though he doesn't act like it and feels no less capable because of it.