Emergent Care / Stabilization: It is important to initially assess the extent of the injury with special attention to whether the toes are neurovascularly intact. Analgesics can be used as needed before moving on to imaging and management. (See Best Tests, Management, and Therapy sections for further details.)

Causes / typical injury mechanism: Metatarsophalangeal (MTP) joint dislocation is an acute injury from high-force trauma, most commonly from motor vehicle accidents, athletic injuries, and falls from heights. Although this is an uncommon injury, the first MTP joint is most likely to be dorsally dislocated as a result of hyperextension, although lateral and plantar dislocations have been reported as well. The lesser MTP joints (second through fifth) are dislocated infrequently; this can be an isolated injury or occur with multiple MTP joints dislocated simultaneously.

Classic history and presentation: MTP joint dislocations most often occur following trauma to the foot. Closed dislocations present with pain and swelling. Open dislocations present with lacerations or wounds around the affected joint. It is possible this injury will have associated bone fracture, ligament and tendon injury, and soft tissue damage.

Prevalence: Uncommon – First MTP joint dislocation prevalence ranges from 0.008%-0.04%.

• Age – Most cases are reported in patients between the ages of 30 and 50 years, but patients have ranged in age from 17-84 years.
• Sex / gender – More common in men.

Risk factors: Acute trauma, joint instability, inflammatory disorders, floating toe syndrome, crossover second toe deformity

Pathophysiology: MTP joint dislocations are caused by the elongation or rupture of the plantar plate, collateral ligaments and tendons of the flexor hallucis longus and brevis, adductor and abductor hallucis, and the extensor hallucis longus and brevis. For the first MTP joint, the injury may or may not involve intersesamoid ligament injury, sesamoid fracture, or sesamoid dislocation.

Grade / classification system: Several classification systems of first MTP joint dislocations have been proposed in the literature. In 1980, Jahss proposed a system for dorsal dislocations. In 2017, Zrig et al reorganized this original classification system and added lateral, dorsolateral and dorsomedial, and plantar dislocations. In 2019, Hood et al added plantar dislocation subtypes to the proposed classification system by Zrig et al.

Zrig et al 2017:
Type 1 – Dorsal dislocation of the first MTP joint
Type 1A – Intersesamoid ligament is intact and sesamoid complex is not dislocated
Type 1B – Intersesamoid ligament is intact and sesamoid complex is dislocated over metatarsal neck
Type 1C – Tearing or avulsion of intersesamoid ligament is present
Type 2 – Lateral and medial dislocations of the first MTP joint
Type 2A – Pure lateral dislocation
Type 2B – Dorsolateral and dorsomedial dislocations
Type 3 – Plantar dislocation of the first MTP joint

Hood et al 2019:
Type 3 – Plantar dislocation of the first MTP joint
Type 3A – Sesamoid complex is not dislocated
Type 3B – Sesamoid complex is dislocated