ACUTE ISOLATED MIDTARSAL (CHOPART’S) DISLOCATION-

CASE REPORTSAn Ortho Club presentation

by

Dr. Libin Thomas Manathara

Junior resident, Department of Orthopaedics, Amala Institute of Medical Sciences

Special thanks to Prof. C. Jayaprakash, Dr. Sudheer U, Dr. Kishore P, Dr. Ajith Jose

CASE #1

CASE REPORT #1

• A 23 year old male sustained an injury to the left foot while playingvolleyball

• He reported landing on a plantar flexed foot and associated varus(medial) stress following a serve

• He was evaluated clinically and no neurovascular deficits were noted

• Xrays were obtained which revealed the manner of injury producingthe deformity- an isolated midtarsal medial displacement

CASE REPORT #1

• After adequate analgesia and sedation, closed manipulative reductionwas attempted by keeping the knee flexed to eliminate the pull of thetendoachilles and providing counter traction

• Traction was applied to the fore and mid foot keeping it plantar flexedwith the dominant hand and the talus with ankle joint was stabilizedwith the non dominant hand

• The distal component was laterally displaced and a definitive “pop”was both heard and felt to denote successful reduction

CASE REPORT #1

• Post reduction vascularity was confirmed to be normal, Xrays wereobtained to confirm the stability of reduction and the left ankle andfoot was immobilized in a below knee plaster of Paris splint

• The splint was converted to a short leg cast 1 week later

• The foot and ankle were immobilized for a total of 6 weeks followingwhich the patient was mobilized and follow up continued

CASE #2

CASE REPORT #2

• A 35-year-old woman fell 6 feet from a wall and landed on her feet,with the left forefoot plantarflexed on the hindfoot, resulting inimmediate pain

• She was initially treated with below-the-knee plaster splintimmobilization at a local hospital

• There was no reduction in pain so she was referred for expertmanagement

• The patient had no other injuries and radiographs of the left foot,after removing the plaster splint, showed isolated dorsal dislocationof the talonavicular joint with subluxation of the calcaneocuboid joint

CASE REPORT #2

• Based on the degree of disruption of ligamentous structure, and theamount of displacement, it was decided that the best treatmentoption for this patient was surgical relocation and stabilization of theleft foot

• Open reduction of the midtarsal joint was thereafter performed

CASE REPORT #2

• An anterolateral approach was used to expose the disruptedligaments and the midtarsal joints

Operative photograph showing the plane of surgery between the extensor digitorum longus and the peroneal tendons of the left foot through an anterolateral skin incision

CASE REPORT #2

• The talonavicular joint was reduced by means of plantarflexing andinverting the forefoot, followed by relocation of the talar head intoanatomical position

Operative photograph showing dorsal dislocation of the navicular over the talus

CASE REPORT #2

• This maneuver resulted in complete anatomical realignment of thetalonavicular joint, after which a single transfixation Kirschner-wire (K-wire) was used to stabilize the correction, and the distal end of the K-wire was kept external on the lateral aspect of the foot

CASE REPORT #2

• Intraoperative image intensification fluoroscopy then revealed thecalcaneocuboid joint to persist to be dislocated, and this portion of the mid tarsaljoint was then reduced with manipulation that entailed distraction anddorsiflexion of the forefoot on the hindfoot and the plantar calcaneonavicular(spring) ligament; the dorsal calcaneocuboid ligament, as well as the capsulartissues, were repaired using 1-0 polyglycolic acid sutures

• Postoperative radiographs, taken with the plaster cast in place, showed completereduction of the mid tarsal joint

• Following the operation, the right foot was immobilized in a short-leg cast for 6weeks, and the K-wire was removed at the 12-week follow-up visit

Postoperative radiograph showing anatomical reduction of the talonavicular and the calcaneocuboid jointsA single 2-mm Kirschner-wire is holding the talonavicular joint reduction

Postoperative clinical photograph showing a single Kirschner-wire with the distal end kept outside the left foot and the anterolateral skin incision

DISCUSSION #1

DISCUSSION

• Midtarsal joints, including the talonavicular and calcaneocuboidjoints, are functionally closely related to the subtalar and Lisfrancjoints

• Isolated midtarsal injury is uncommon

DISCUSSION

• Main and Jowett classified a series of 71 midtarsal joint injuries into 5groups according to the direction of the deforming force and theresulting displacement:

• medial forces

• longitudinal forces

• lateral forces

• plantar forces

• crush injury

DISCUSSION

• Medial- Medial forces caused• fracture-sprains

• fracture subluxation or dislocation

• swivel dislocation

DISCUSSION

• Fracture-sprains-These are caused by inversion strains of the foot.Radiographs show flake fractures of the dorsal margins of the talus ornavicular and of the lateral margins of the calcaneus or cuboid

• Fracture-subluxations and dislocations- The forefoot is displacedmedially, leaving the hindfoot in normal alignment with the tibia

DISCUSSION

• Swivel dislocations- High falls accounted for most of these as well asfor the fracture-subluxations and dislocations

• A medial force applied to the forefoot disrupts the talo-navicular jointbut leaves the calcaneo-cuboid joint intact

• The foot rotates medially but does not invert or evert, the axis ofrotation appearing to be the interosseous talo-calcaneal ligament,which remains intact

• This contrasts with the more common occurrence in which thisligament ruptures, allowing subtalar dislocation

Medial swivel dislocation

The antero-posterior view shows dislocation of the talo-navicular component: the calcaneus has swivelled beneath the talus, taking with it the cuboid

Medial swivel dislocation

An oblique view shows the calcaneo-cuboid component intact

Medial swivel dislocation

A lateral view shows the talus and the ankle in oblique profile in a vertical plane, but the calcaneus and the rest of foot are in true lateral profile, indicating that the calcaneus has swivelled beneath the talus

DISCUSSION #2

DISCUSSION

•Dorsal forces disrupted the plantar ligamentous structure, resulting indorsal midtarsal dislocation

•The Hong Kong paper was the first report of an isolated dorsal midfootdislocation

•It is rare because of the strong ligamentous structures around themidtarsal joint: the strongest ligamentous structures of the midtarsaljoint are on the plantar side which is protected by

• the long and short plantar ligament

• bifurcate ligament

• the plantar calcaneonavicular (spring) ligament

which are important as supports for the arch of the foot

DISCUSSION

• Therefore, dorsal midtarsal dislocation resulting from disruption ofthese plantar ligaments is less common than other types of midtarsaldislocation

• The mechanism of injury in the Hong Kong paper was a dorsallydirected force that disrupted the plantar ligamentous structures ofthe MTJ, resulting in dorsal displacement of the forefoot on thehindfoot following a fall from a height

• Whereas in case report #2, the patient had also fallen from a heightof 6 feet and landed on both feet, with the left forefoot plantarflexedon the hindfoot

DISCUSSION

• Perhaps the resultant plantarflexory force sustained at the MTJ,without concomitant plantarflexion of the ankle, may have disruptedthe dorsal and plantar ligamentous structures of the MTJ, injuries thatwere identified intraoperatively, thereby causing isolated dorsal MTJdislocation

• This mechanism of injury is unusual and that the patient described,case report #2, represents the first such case described in theliterature

CONCLUSION

• Early anatomical reduction and stable fixation has been shown toimprove the clinical results in these types of midfoot dislocation

• In our first case the nature of injury was an isolated midtarsal jointdislocation- talonavicular alone (medial), which was stable withclosed reduction and plaster immobilisation

• The patient is still under follow up and functional outcome monitored

• In the second case dislocation of both talonavicular andcalcaneocuboid joints warranted additional fixation with K- wire giventhe unique nature of the dislocation, namely dorsal

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