The term turf toe refers to hyperextension injuries of the first metatarslophalangeal joint, originally described in football players on artificial turf (“astroturf”).
Anatomy: The sesamoid bones are fixed proximally by thin, usually invisible metatarso-sesamoid ligaments and distally by strong sesamophalangeal ligaments. In addition, the tendons of the two heads of the flexor hallucis brevis muscle attach proximally into the sesamoid bones. Laterally, they are connected to the capsule by the accessory collateral ligaments. The abductor hallucis tendon merges laterally with this complex and the adductor hallucis tendon and the deep transverse intermetatarsal ligament medially. A strong intersesamoid ligament runs between the sesamoid bones. From this ligament a thin capsular structure, which covers the flexor hallucis longus tendon, extends to the base phalanx. Some authors refer to this entire plantar complex as the “plantar plate” of the greater toe [Crain JM et al., Ashimolowo T et al.] others only to the thin central part between the sesamophalangeal ligaments [Nery C et al.].
Due to this inconsistent nomenclature, it is recommended not to use the term “plantar plate” at the big toe, but to refer directly to the structures of the above-mentioned capsuloligamentous-sesamoid complex.
As with the other toes, injuries to the plantar capsule can extend into the collateral ligaments.
Normal findings of the plantar capsular structures of the greater toe. Due to the effusion caused by a cartilage damage at the phalanx, the central part of the capsule is unusually well recognized and can be distinguished from the underlying flexor hallucis longus tendon. Note the recesss of the capsule at its distal attachment.
Hyperextension injury five weeks ago. Unremarkable intersesamoid ligament. A tear of the capsule is visible distal to the sesamoids (red arrow). The sagittal images show a normal sesamophalangeal ligament medially (green arrow). Laterally, only a remnant of the sesamophalangeal ligament surrounded by edema is visible (blue arrow).
Turf toe. The intersesamoidal ligament remains intact (red arrow). Just distally to the sesamoid bones, there is a tear of the joint capsule (green arrow) as well as a tear of the lateral sesamophalangeal ligament (blue arrow).