Flexor Hallucis Longus Tendinopathy: Posteromedial Ankle Impingement, Hallux Loading, and Footwear

Flexor Hallucis Longus Anatomy and the Sustentaculum Tali Pulley

The flexor hallucis longus muscle originates along the posterior fibula, passing through a fibro-osseous tunnel beneath the sustentaculum tali before running along the plantar sole to insert into the distal phalanx of the great toe. This anatomical pulley allows the big toe to grip the ground powerfully during late stance.

Pathomechanics: Excessive Hallux Extension and Repetitive Friction

Repetitive forced dorsiflexion of the ankle accompanied by hallux extension increases tensile shear across the sustentaculum tali. In dancers, runners, and active walkers with rigid forefoot biomechanics, this friction produces stenosing tenosynovitis and posteromedial ankle pain.

Supportive Footwear, Stiff Rocker Soles, and Load Modification

Shoes featuring forefoot rocker geometry and stiffened toe boxes significantly diminish the bending angle required at the great toe during terminal stance. Gentle soft-tissue mobilization and eccentric toe flexor loading restore pain-free push-off capacity.

When to Seek Professional Clinical Evaluation

Posteromedial ankle tenderness triggered by resisted great toe flexion or sensations of triggering behind the inner ankle bone warrants diagnostic evaluation by a licensed podiatrist or orthopedic sports medicine specialist.

Sources

1. Forefoot rocker footwear mechanics and great toe joint offloading during walking gait
2. Flexor hallucis longus tendinopathy in athletes: anatomy, biomechanics, and conservative management