Can you give us anything more to go on as to where or how you heard this?
Was it NPR specifically, or your local NPR affiliate?
Keep in mind that "NPR" programming often consists of actual network programming, independent works distributed by NPR, and productions from either affiliated subnetworks (e.g., "MPR", Minnesota Public Radio, PRI/PRX, APM), and in cases individual affiliate stations (WBUR, WAMU, WNYC, WHYY, KQED, KOUW, KUTX, KCRW, etc.), or other noncommercial radio networks (e.g., Pacifica). And increasingly podcasting networks.
Using NPR's site search, the most recent story focusing on a specific ballerina's injury story is from 2017, on Fresh Air (WHYY) "From Injury To Recovery, A Ballerina Fought To Retire On Her Own Terms" <https://www.npr.org/2017/07/10/536434340/from-injury-to-reco...>. It's possible that that replayed more recently. Or that you're loosely anchored in time.
There's a story more closely matching your description, though focusing on gymnastics, in USA Today, March 2026, "How two painful sports stories underscore girls' unique injury risks" <https://www.usatoday.com/story/sports/2026/03/08/girls-great...>
My memory was that this was an NPR story, the local affiliate has distinct production values that I believe I would have noticed. However, even searching the local affiliate's site only yielded the stories you referenced.
My only other suggestion is that stories often get shopped around and carried by multiple outlets. If you're anything like me, "the past year" might actually be the past five years, or more. There's often a study, book, institute, or specific investigator/doctor behind the story. If you really want to track down the story you might try broadening your search on those dimensions. (Or others which come to mind.)
Good luck!