The document describes two case reports of acute isolated midtarsal dislocations. Case 1 involved a 23-year-old male who sustained a medial talonavicular dislocation playing volleyball, which was treated with closed manipulation and casting. Case 2 involved a 35-year-old woman who fell from a height onto a plantarflexed foot, causing dorsal dislocation of the talonavicular and calcaneocuboid joints, requiring open reduction and K-wire fixation. The discussion covers classification of midtarsal injuries, mechanisms of various dislocation patterns, and the rarity of isolated dorsal midtarsal dislocations. Early anatomical reduction and stable fixation were concluded to improve outcomes for these midfoot dislocation injuries.

1. ACUTE ISOLATED MIDTARSAL
(CHOPART’S) DISLOCATION-
CASE REPORTS
An 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

2. CASE #1

3. CASE REPORT #1
• A 23 year old male sustained an injury to the left foot while playing
volleyball
• 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 producing
the deformity- an isolated midtarsal medial displacement

5. CASE REPORT #1
• After adequate analgesia and sedation, closed manipulative reduction
was attempted by keeping the knee flexed to eliminate the pull of the
tendoachilles and providing counter traction
• Traction was applied to the fore and mid foot keeping it plantar flexed
with the dominant hand and the talus with ankle joint was stabilized
with the non dominant hand
• The distal component was laterally displaced and a definitive “pop”
was both heard and felt to denote successful reduction

6. CASE REPORT #1
• Post reduction vascularity was confirmed to be normal, Xrays were
obtained to confirm the stability of reduction and the left ankle and
foot 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 following
which the patient was mobilized and follow up continued

8. CASE #2

9. 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 in
immediate pain
• She was initially treated with below-the-knee plaster splint
immobilization at a local hospital
• There was no reduction in pain so she was referred for expert
management
• The patient had no other injuries and radiographs of the left foot,
after removing the plaster splint, showed isolated dorsal dislocation
of the talonavicular joint with subluxation of the calcaneocuboid joint

12. CASE REPORT #2
• Based on the degree of disruption of ligamentous structure, and the
amount of displacement, it was decided that the best treatment
option for this patient was surgical relocation and stabilization of the
left foot
• Open reduction of the midtarsal joint was thereafter performed

13. CASE REPORT #2
• An anterolateral approach was used to expose the disrupted
ligaments and the midtarsal joints

14. 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

15. CASE REPORT #2
• The talonavicular joint was reduced by means of plantarflexing and
inverting the forefoot, followed by relocation of the talar head into
anatomical position

16. Operative photograph
showing dorsal dislocation of
the navicular over the talus

17. CASE REPORT #2
• This maneuver resulted in complete anatomical realignment of the
talonavicular 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

18. CASE REPORT #2
• Intraoperative image intensification fluoroscopy then revealed the
calcaneocuboid joint to persist to be dislocated, and this portion of the mid tarsal
joint was then reduced with manipulation that entailed distraction and
dorsiflexion of the forefoot on the hindfoot and the plantar calcaneonavicular
(spring) ligament; the dorsal calcaneocuboid ligament, as well as the capsular
tissues, were repaired using 1-0 polyglycolic acid sutures
• Postoperative radiographs, taken with the plaster cast in place, showed complete
reduction of the mid tarsal joint
• Following the operation, the right foot was immobilized in a short-leg cast for 6
weeks, and the K-wire was removed at the 12-week follow-up visit

19. Postoperative radiograph
showing anatomical
reduction of the
talonavicular and the
calcaneocuboid joints
A single 2-mm Kirschner-
wire is holding the
talonavicular joint reduction

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

21. DISCUSSION #1

23. DISCUSSION
• Midtarsal joints, including the talonavicular and calcaneocuboid
joints, are functionally closely related to the subtalar and Lisfranc
joints
• Isolated midtarsal injury is uncommon

25. DISCUSSION
• Main and Jowett classified a series of 71 midtarsal joint injuries into 5
groups according to the direction of the deforming force and the
resulting displacement:
• medial forces
• longitudinal forces
• lateral forces
• plantar forces
• crush injury

26. DISCUSSION
• Medial- Medial forces caused
• fracture-sprains
• fracture subluxation or dislocation
• swivel dislocation

27. DISCUSSION
• Fracture-sprains-These are caused by inversion strains of the foot.
Radiographs show flake fractures of the dorsal margins of the talus or
navicular and of the lateral margins of the calcaneus or cuboid
• Fracture-subluxations and dislocations- The forefoot is displaced
medially, leaving the hindfoot in normal alignment with the tibia

28. DISCUSSION
• Swivel dislocations- High falls accounted for most of these as well as
for the fracture-subluxations and dislocations
• A medial force applied to the forefoot disrupts the talo-navicular joint
but leaves the calcaneo-cuboid joint intact
• The foot rotates medially but does not invert or evert, the axis of
rotation appearing to be the interosseous talo-calcaneal ligament,
which remains intact
• This contrasts with the more common occurrence in which this
ligament ruptures, allowing subtalar dislocation

31. 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

32. Medial swivel dislocation
An oblique view shows the calcaneo-cuboid component intact

33. 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

34. DISCUSSION #2

37. DISCUSSION
•Dorsal forces disrupted the plantar ligamentous structure, resulting in
dorsal midtarsal dislocation
•The Hong Kong paper was the first report of an isolated dorsal midfoot
dislocation
•It is rare because of the strong ligamentous structures around the
midtarsal joint: the strongest ligamentous structures of the midtarsal
joint 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

40. DISCUSSION
• Therefore, dorsal midtarsal dislocation resulting from disruption of
these plantar ligaments is less common than other types of midtarsal
dislocation
• The mechanism of injury in the Hong Kong paper was a dorsally
directed force that disrupted the plantar ligamentous structures of
the MTJ, resulting in dorsal displacement of the forefoot on the
hindfoot following a fall from a height
• Whereas in case report #2, the patient had also fallen from a height
of 6 feet and landed on both feet, with the left forefoot plantarflexed
on the hindfoot

41. DISCUSSION
• Perhaps the resultant plantarflexory force sustained at the MTJ,
without concomitant plantarflexion of the ankle, may have disrupted
the dorsal and plantar ligamentous structures of the MTJ, injuries that
were identified intraoperatively, thereby causing isolated dorsal MTJ
dislocation
• This mechanism of injury is unusual and that the patient described,
case report #2, represents the first such case described in the
literature

42. CONCLUSION
• Early anatomical reduction and stable fixation has been shown to
improve the clinical results in these types of midfoot dislocation
• In our first case the nature of injury was an isolated midtarsal joint
dislocation- talonavicular alone (medial), which was stable with
closed reduction and plaster immobilisation
• The patient is still under follow up and functional outcome monitored
• In the second case dislocation of both talonavicular and
calcaneocuboid joints warranted additional fixation with K- wire given
the unique nature of the dislocation, namely dorsal

43. THANK YOU