A 3-dimensional (3D) computed tomography (CT) reconstruction of the right foot of a 32-year-old man with severe foot pain and deformity shows incongruence of the talonavicular and calcaneocuboid joints.
A 32-year-old man presents to the emergency department with severe right foot pain and deformity after an injury 2 hours prior. He was running and may have stepped on an uneven surface, twisting his ankle. He immediately fell to the ground and was unable to bear weight afterward. He also noticed that his toes pointed inward and the foot was obviously deformed. On examination in the emergency department, obvious medial deviation of the foot is noted, starting at the midfoot. Radiograph and computed tomography (CT) reports reveal no fractures or deformity. However, 3-dimensional CT reconstructions of the right foot show incongruence of the talonavicular and calcaneocuboid joints.
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The Chopart joint is composed of the talonavicular joint and the calcaneocuboid joint (also referred to as the midtarsal joint or the articulation between the midfoot and hindfoot). Chopart was a French surgeon who performed amputations at the midtarsal joint, a procedure still commonly performed in those with diabetes. A Chopart dislocation occurs when the midfoot (navicular and cuboid) separates from the hindfoot (calcaneus and talus). The Chopart joint is held together by several strong capsular-ligamentous structures, including the talonavicular, calcaneonavicular, and calcaneocuboid ligaments. Forceful adduction of the plantar flexed forefoot with a fixed hindfoot can disrupt these ligaments and cause dislocation with or without fracture.1,2
Chopart dislocations can be missed because of the lack of obvious radiographic findings and the rarity of the injury. Deformity of the foot may be the only obvious sign. Once Chopart dislocation has been diagnosed, urgent closed reduction should be performed in the emergency department. External fixation is then performed in the operating room to maintain the reduction while the ligaments of the midfoot heal. Patients should remain non-weight-bearing until the external fixator is removed, typically at 4 weeks postoperatively. The external fixator is then replaced with a short-leg cast for an additional 4 weeks. At 8 weeks postoperatively, gradual weight bearing is allowed.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).
- Benirschke SK, Meinberg EG, Anderson SA, Jones CB, Cole PA. Fractures and dislocations of the midfoot: Lisfranc and Chopart injuries. J Bone Joint Surg Am. 2012;94:1326-1337.
- Schmitt JW, Werner C, Ossendorf C, Wanner GA, Simmen HP. Avulsion fracture of the dorsal talonavicular ligament: a subtle radiographic sign of possible Chopart joint dislocation. Foot Ankle Int. 2011;32:722-726.