Midtarsal injuries are rare injuries of the midtarsal joint of the foot, comprising of the talonavicular joint (TNJ) and the calcaneocuboid joint (CCJ), collectively known as the Chopart joint. These joints are involved in movements, such as foot adduction-abduction and foot inversion-eversion. Studies suggest 41 % of these injuries are missed during initial assessment due to difficulties in diagnosing purely through radiographs, suggesting a more clinical mode of diagnosis is more feasible ^[1]. Main and Jowett first described a classification useful to study midtarsal dislocations, broadly divided into pure dislocations and fracture dislocations ^[1]. We present one such case that was initially missed on initial management, later diagnosed and treated for the same.

We present a case of a 24-year-old active Male, avidly participating in recreational activities before he suffered a road traffic accident causing a fall from his two-wheeler vehicle in February 2025. He sustained injuries to his right ankle. He was treated at a hospital near his home, where he was diagnosed a closed right extra-articular calcaneum fracture with second metatarsal shaft fracture, along with a deep abrasion over the dorsum of the ankle and foot. He was operated for the same with screw fixation of the calcaneum fracture with percutaneous pinning for the second metatarsal fracture (Fig. 1).

He was then subject to serial dressings and cast applications for the next 4 months. At the end of 4 months, when the cast was removed, the abrasion was found to be non-healing, along with a deformity in the foot and ankle was noted. He then underwent split-thickness skin grafting for his ankle skin defect in June 2025. He then presented to us at 6 months post-injury to seek consultation for his deformity.

On examination, he had a walker-assisted-non-weight bearing gait with weight on the left lower limb. The right ankle was in equinus, with the forefoot in adduction and a grossly supinated midfoot. There was crowding of the toes with the great toe in varus and the second toe overriding it dorsally. The dorsalis pedis and posterior tibial pulses were well felt. Movements at the tibiotalar joint were restricted in equinus; correcting supination would elicit pain (Fig. 2).

Radiographs and computed tomography (CT) were suggestive of an osteopenic bone stock, with dislocated CCJ and medially subluxed TNJ (Fig. 3). The Subtalar joint was also distracted laterally. He underwent the following procedure (Fig. 4): Tendoachilles lengthening (equinus component), Midfoot fusion (midtarsal dislocation), Ankle arthrodesis with fibula osteotomy and iliac crest bone grafting (lateral ligament complex injury and chronicity of injury).

The Chopart joint, including the TNJ and CCJ, while the CCJ takes part in 20–30% of inversion – eversion at the hindfoot ^[2], TNJ takes part in the pronation and supination of the tarsus ^[3]. The Chopart joint, comprised of the TNJ and CCJ, is stabilized by the dorsal talonavicular ligament, the bifurcate ligament, the Dorsal calcaneocuboid ligament, with the plantar calcaneocuboid ligament. It is an injury to these ligaments that causes midtarsal dislocation. The Chopart joint can be diagnosed well in the anteroposterior view by drawing the Cyma line, an S-shaped congruent line dividing the midfoot from the hindfoot. Any incongruency may suggest an issue with the Chopart joint. These dislocations often happen due to medial force onto the forefoot in a plantar flexed ankle. The Navicular subluxed medially, with pivot being the intraosseous talocalcaneal ligament; hence, the CCJ remains reasonably intact, with the calcaneum swiveling to face medially underneath the talus, but still maintaining its vertical position with respect to the talus (Fig. 5).

Main and Jowett in 1975 described such injuries based on force applied having five basic types: Medial, longitudinal, lateral, plantar, and crush injuries ^[1]. In this particular case, the navicular is merely subluxed, with subluxation also in the CCJ and laterally distracted subtalar joint, leading to an added inversion component. The injury patterns described by Main and Jowett have been an easy way to understand midtarsal dislocations. They included 71 patients in their study, 31 of whose diagnosis was delayed due to inadequate radiographs ^[1]. A couple of case reports by Sakharkar et al. ^[4] and Datt et al. ^[5] describe acute midtarsal dislocation. Milgram reported a chronic subluxation that was treated with midfoot fusion ^[6].

The presented case portrayed a more gradual presentation of deformity, suggesting a ligament insult laterally with the forefoot eventually failing to retain its position, shifting to an inverted and adducted position. Neglection of these injuries has been reported upto 41% in acute midtarsal dislocation, although Howie et al reported five out of seven patients in their study of midtarsal occult subluxation were initially missed ^[7]. An interesting study by Behrens et al. maps the progressive collapse and foot deformity in peri-talar subluxation using three-dimensional pressure mapping ^[8]. In case of an acute injury, the treatment recommended for best outcomes is open reduction and internal fixation for both pure type and fracture dislocations ^[9]. Research articles do suggest that a higher index of suspicion is needed to diagnose such injuries, as neglection may lead to permanent disability ^[10].

The case presented here can be diagnosed as a case of neglected chronic right medial swivel midtarsal pure subluxation, as this patient has some continuity of the TNJ and CCJ, with a vertical profile of calcaneum. Due to chronicity of the injury, restricted deformities, and the patient’s goals of care, it was planned for tendoachilles lengthening with midfoot fusion and ankle arthrodesis. This injury was missed initially due to deceptively intact TMJ and CCJ, showing only mild subluxation in the initial radiograph and CT ^[11]. A high index of suspicion must be maintained to diagnose such injuries. A couple of shortcomings in our study include the unavailability of on MRI to document ligament injury, and also that a long-term follow-up is required to understand functional outcome and Gait characteristics.

Missed midtarsal injuries often lead to disabling deformities, which eventually lead to the need for fusion at midtarsal and also the tibio-talo-calcaneal joint, if the disease and deformity progresses. Early diagnosis and prompt treatment are necessary, so that the patient has a chance at full functionality. Although often missed, radiological guidelines do help in diagnosing such injuries.