Yes, CP did this about 18 months ago when she was 11. At the time she was tumbling level 5 and competing in level 3 and 4 teams. Wasn't injured at cheer, she was climbing a tree at school and fell out.
Fracture and dislocation which was fixed with surgery with a screw. She wore an elbow brace for a while post surgery rather than a hard cast which allowed her to retain some flexibility in the joint. She had about three months with no stunting, tumbling or pressure through the elbow at all, then started working on her strength and on to tumbling slowly over the course of a month. We're lucky that one of her coaches is a physiotherapist and gave her exercises to do at home and kept a close eye on her at the gym. She found she got all her skills back quickly, she was back doing fulls about a month after getting the ok from the doctor to start working through the joint.
She did a season with the screw in her elbow, then went in for surgery again to have it removed this summer as it was quite visible through her skin and may have started to cause irritation. Recovery from that was about a month with no tumbling or stunting. That was hard as she's now on an IO5 team and the stunting was already a steep learning curve for her. All good now though and she's looking forward to her first Worlds in 2020.