Can an accessory navicular stress fracture cause flexor hallucis longus tendinitis in a runner?

I was on a second opinion call with a runner. She developed a stress fracture in her accessory navicular bone. If that wasn’t enough, she then started having pain in her arch in the tendon that pulls on her big toe. That tendon is called the Flexor Hallucis Longus Tendon, or FHL Tendon. Can an accessory navicular stress fracture cause flexor hallucis longus tendinitis in a runner? Well, the short answer is yes, and I am going to explain how in today's episode of the Doc On The Run podcast.