Xrays won’t show any soft tissue damage. She could have luxating patellas Very common in toy breeds.He didn't say if he did but they did several X-rays and redid them after she squirmed to much.
The smaller of the 2
***Edit- it always seemed to happen after an attempted jump. She was still running around the yard 2 days ago
https://www.akc.org/expert-advice/health/luxating-patella-dog/