Ortho Dx: MTP joint fracture dislocation

Fracture dislocations of the metatarsophalangeal (MTP) joint are rare injuries. Management of these injuries in the emergency room setting includes an attempt at closed reduction using local anesthesia. Any deviation of the metatarsal heads should be reduced to restore alignment....

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Fracture dislocations of the metatarsophalangeal (MTP) joint are rare injuries. Management of these injuries in the emergency room setting includes an attempt at closed reduction using local anesthesia. Any deviation of the metatarsal heads should be reduced to restore alignment. Closed reduction is successful about 50% of the time with MTP joint dislocations. Multiple metatarsal neck fractures can be very difficult to reduce. Whether the reduction is successful or not, the patient can follow up with orthopedics in 24 to 48 hours for definitive fixation. An irreducible fracture dislocation of the MTP is not a surgical emergency and can be treated in an outpatient setting. Indications for closed reduction include fracture angulation >10 degrees along the long axis of the metatarsal or >4 mm of translation of the shaft. The goal of closed reduction is to reduce a plantar flexed metatarsal head and impale the head back on the shaft. A percutaneous pin is usually placed through the base of the proximal phalanx, through the metatarsal head and fracture, and into the metatarsal shaft to secure reduction. Fixation helps prevent the natural tendency of the distal metatarsal fractures to drift laterally. Postoperatively, the patient is allowed to weight bear through the heel. Pins are often removed at 4 weeks postoperatively.^1,2

Simple dislocations, such as the 5th MTP joint in this patient, can be treated successfully with closed reduction alone. The surrounding soft tissues of the MTP joint provide adequate stability without the need for pin fixation. The main supporting structures include medial and lateral MTP joint collateral ligaments and the plantar plate. The plantar plate is a broad, thick ligamentous structure that spans the plantar aspect of the MTP joint. Open treatment can often disrupt these soft tissue structures causing MTP joint instability, so closed treatment is preferred.^1,2

Dagan Cloutier, MPAS, PA-C, practices in a multispecialty orthopedic group in the southern New Hampshire region and is editor-in-chief of the Journal of Orthopedics for Physician Assistants (JOPA).

References

1. Early JS. Fractures and dislocations of the midfoot and forefoot. In: Rockwood and Green’s Fractures in Adults. 6th ed. Philadelphia: Lippincott Williams and Wilkins; 2006:2370-2381.
2. Aitken AP, Poulson D. Dislocations of the tarsometarsal joint. J Bone Joint Surg Am. 1963;45A:246-260.