10/26/2026
At 40, Mike Brennan tore his ACL, MCL, and meniscus when two training partners crashed into his knee during a Krav Maga session. As someone who logged 30-plus mile trail runs, he wondered if his athletic life was over.
Mike chose the BEAR Implant, performed by Kai Mithoefer, MD of Boston Bone and Joint Institute, to heal his own ACL rather than replace it with a graft. He has since run more than 15 ultramarathons.
This past Saturday, Mike returned to the Womp Romp 50K in Hingham, MA, and set a personal record for the distance, finishing in 5:28. Four years older and post-surgery, he beat his previous best. “My knee felt great the whole time and it continues to be solid no matter what I throw at it,” he said.
🔗Read Mike's story, including safety information: https://miachortho.com/bear-necessities/mikes-story-from-an-acl-tear-during-krav-maga-to-running-ultramarathons-with-the-bear-implant