Tibialis posterior tendon injury

1. Where does the tibialis posterior originate and insert?
2. What is the function of the tibialis posterior?
3. How is the TP usually injured?
4. What is seen clinically in TP injury?
5. What is the treatment?

Answers:
1. Origin is interosseous membrane and posterior surface of tibia and fibula. Insertion is the tuberosity of the navicular cuboid and base of 2-4 metatarsals.
2. PF and inversion of foot, maintains medial longitudinal arch.
3. Injured by repetitive forceful inversion, often associated with an accessory navicular.
4. Insidious onset of posteromedial ankle pain, medial hindfoot swelling, increased pain with pushoff. If rupture, will have "too many toes" sign.
5. Treat same as lateral ankle sprain, may need orthotics. If rupture, may need tendon transfer.