A Chopart's fracture-dislocation is a dislocation of the mid-tarsal joints of the foot, often with associated fractures of the calcaneus, cuboid and navicular bone.
Clinically Relevant Anatomy
The transverse tarsal joint is also called the midtarsal joint and is referred to as Chopart’s joint. The midtarsal joint is composed of the talonavicular and calcaneocuboid joints. The bones which go into the formation of this Chopart joint are the talus and calcaneus proximally, and the navicular and cuboid bone distally. When the foot skeleton is viewed from above, the joint line of the transverse tarsal articulation has the shape of an S.
Epidemiology / Etiology
Among the uncommon midfoot injuries, Chopart joint dislocations or fracture-dislocations are the most severe injuries. Chopart fracture-dislocations are caused most commonly by motor vehicle accidents and falls from a height. Avulsion fractures localized to the midfoot are typically caused by low-energy trauma, e.g., sprain or sports injuries. Concomitant fractures occur in approximately 75% to 90% of Chopart injuries, and only 10% to 25% of the Chopart dislocations are pure ligamentous injuries. Injuries with a combined Chopart and Lisfranc fracture-dislocation are often part of so called "crush" injuries of the foot.
Main and Jowet classified midtarsal joint injuries into 5 groups, according to the direction of the deforming force and the resulting displacement of the forefoot (blue region in the picture):
(1) medial force with medial displacement
(2) longitudinal force with impaction and twisting
(3) lateral force with lateral displacement
(4) plantar force with plantar displacement
(5) crush injury 
Chopart joint dislocations and especially fracture-dislocations are still problematic in both diagnosis (they are missed or misdiagnosed in up to 41% of cases) and treatment and result in a high degree of long-term morbidity. Isolated midtarsal dislocations are rare because of the close proximity of the midtarsal to subtalar and Lisfranc joints.
Crush injuries of the foot often cause gross soft tissue damage and have very high rates of deep infection.
The symptoms and signs of a Chopart fracture-dislocation are: Abnormal position of the forefoot to medial direction, swelling of the dorsum of foot and pain in the midtarsal region when it gets strained.
Injuries involving the Chopart joint complex are rare and frequently missed or misdiagnosed. Dislocation is often combined with fracture in these areas. Serious injuries may present in a subtle manner and are often misdiagnosed as a sprain. Small avulsion fractures of the navicular and cuboid may be misdiagnosed as a simple avulsion when in fact they represent a more severe midfoot injury. A high index of suspicion is required.
For the initial diagnosis, x-rays in three views (dorsoplantar, lateral and oblique) are currently recommended. In case of a present injury or in doubt, a CT scan or MRI should be performed. Knowledge of the exact radiographic projections is essential for making the correct diagnosis. For preoperative planning the routine use of computed tomographic scanning is suggested. In any case of isolated navicular or cuboid compression fractures a corresponding ligamentous injury to the other side of the mid-tarsal joint has to be ruled out by stress films.
Furthermore the examination of the foot should include an evaluation of the patient's gait and extra attention should be paid to malalignment and swelling of the foot.
A nonoperative treatment is used in nondislocated or minimally dislocated fractures. Closed reduction is the most known nonoperative treatment. After closed reduction a rigid leg cast for 6 to 8 weeks with partial weight bearing will be applicated. Medicines against deep venous thrombosis are given to patients, treated with a short leg cast. Though external fixation is a useful tool for the treatment of complex foot injuries, it is said by patients that it produces stiffness of the foot and ankle.
The reduction should be open if the closed reduction could not achieve anatomic conditions.
The aim of treatment of a Chopart fracture or dislocation should be reconstruction of the medial and lateral foot arch, and achieving congruent joint surfaces and ligamentous stability. To this end, attention should be paid to the talonavicular joint, because it is essential for satisfactory function of the ankle. Traditionally, open reduction improves outcome in Chopart fracture-dislocations and complex midfoot fractures, because ligamentous structures can be repaired and joint surfaces can be reconstructed.
Physical therapy intervention begins shortly after the necessary immobilization period in both operative and conservative treatment. Interventions include: reduction of edema, strengthing exercises to address post immobilization atrophy, flexibility exercises, gait training. Also, early mobilization is important to prevent the joint from becoming stiff and learning the mobilization without strain with the aid of a walking aid. The physical therapist can also work on activities of daily living , such as climbing stairs.
Midfoot injuries have a high rate of mid and long-term morbidity. Only recognized isolated fractures of the midfoot have an outcome with minimal functional impairments. In contrast, a fracture dislocation of a midfoot bone results in a higher morbidity. This because of its crucial role in the balance and stability of the foot.
The prognosis is good if exact reduction is achieved and the patient is mobilized rapidly. If the injury doesn’t results in chronic subluxation, the patient is mobilized rapidly. If the injury results in chronic subluxation, the patient often has chronic pain exacerbated by loading and osteoarthritis will develop in the involved joints. Polytrauma patients, open injuries, and the occurrence of compartment syndrome have been identified as significant variables that worsen final outcome after midfoot fractures and dislocation.
Finally, because of the risk of developing posttraumatic arthrosis, long-term follow-up evaluation is an important aspect of the management of patients who have sustained dislocation of the mid tarsal joint.
Recent Related Research (from Pubmed)
- Puthezhath, K., Veluthedath, R., Kumaran, C.M., & Patinharayil, G. (2009). Acute Isolated Dorsal Midtarsal (Chopart's) Dislocation: A Case Report [electronic version]. The Journal of Foot and Ankle Surgery, Vol. 48, No.4 , 462-465. B
- Signe Brunnstrom, M.A. (1975). Clinical Kinesiology. Philadelphia: F.A. Davis Company.
- Richter, M., Thermann, H., Huefner, T., Schmidt, U., Goesling, T., & Krettek, C. (2004). Foot & Ankle International, Vol 25., No.5, 340-348. 5 november, 2011. http://www.krankenhaus-rummelsberg.de/uploads/tx_templavoila/chopart.pdf
- Van Dorp, K.B., De Vries, M.R., Van der Elst, M., & Schepers, T. (2010). Chopart Joint Injury: A Study of Outcome and Morbidity [electronic version]. The Journal of Foot and Ankle Surgery, Vol. 49, No. 6, 541-545. C
- Richter, M., Wippermann, B., Krettek, C., Schratt, H.E., Hufner, T., & Thermann, H. (2001). Foot & Ankle International, Vol. 22, No. 5, 392-379. 5 november, 2011. http://olc.metrohealth.org/SubSpecialties/Trauma/Media/Other/Fractures%20and%20fracture-dislocations%20of%20the%20midfoot,%20occurrence,%20causes,%20long-term%20results.pdf A
- Ip, K.Y., & Lui, T.H. (2006). Journal of Orthopaedic Surgery, 14(3), 357-359. 11 november, 2011. http://www.josonline.org/pdf/v14i3p357.pdf B
- Bahr, R., & Maehlum, S. (2004). Clinical Guide to Sports Injuries. Oslo: Human Kinetics.
- Makwana, K.N., & Van Liefland, M.R. (2005). Injuries of the midfoot [electronic version]. Current Orthopaedics, Vol. 19, No. 3, 231-242. A
- Frink, M., Geerling, J., Hildebrand, F., Knobloch, K., Zech, S., Droste, P., …, Richter, M. (2006). Etiology, treatment and long-term results of isolated midfoot fractures [electronic version]. Foot and Ankle Surgery, Vol. 12, 121-125. A
- Rammelt, S., Biewener, A., Grass, R., & Zwipp, H. (2004). Diagnostik und Therapie von Chopart-Luxationsfrakturen [electronic version]. Aktuelle Traumatologie Y, Vol. 34, No. 1, 16-25. A