CASE 129

By: Dr. Nizar Al-Nakshabandi MD, FRCPC

HISTORY: 29-year-old horse back rider injured his ankle while trying to get on the horse.

What are your findings?

What is the differential diagnosis?

What are the causes?

FINDINGS:

The AP view of the tibia and fibula [A] demonstrates a spiral fracture of the proximal fibula. Furthermore, the ankle AP, and oblique views [B and C respectively] demonstrate widening of the medial talotibial ankle joint due to distal tibiofibular syndesmosis or deltoid ligament disruption. The talus does not sit symmetrically in the ankle mortise. Widening of the tibiofibular space is also observed.

DIAGNOSIS:

Maisonneuve-fracture dislocation.

PEARLS AND DISCUSSION:

The mechanism of injury in these fracture-dislocations is pronation with external rotation mechanism. Classically in the exam situation you would be given an AP and oblique view of the ankle and once you the detect the tibiofibular syndesmosis disruption or suspected deltoid ligament the examiner will tell you would you like to see any other images or order any other views you should mention that I would like to take a look at the proximal tibia and fibula where you will see the spiral fracture of the fibula. Alternatively, you may just be given the AP view of the proximal tibia and fibula and you should then ask for the ankle views.

The proximal fibular fracture does not require any surgical treatment, unlike the syndesmosis, will require approximation and 2 screws for 2 points of fixation is a surgical treatment.

FURTHER READING:

1.      Forster BB, Lee JS, Kelly S et-al. Proximal tibiofibular joint: an often-forgotten cause of lateral knee pain. AJR Am J Roentgenol. 2007;188 (4): W359-66. 

2.      Maisonneuve, J. G. (1840). Recherches sur la fracture du péroné. Paris. France: Loquin & Cie.