Trimalleolar Fracture — Mechanism, Classification, Treatment and Surgical Approaches
DNB Orthopaedics • October 2024 • Paper IV • 10 Marks
Introduction
A trimalleolar ankle fracture consists of fractures involving the lateral malleolus, medial malleolus and posterior malleolus. It represents an unstable injury of the ankle ring and is commonly associated with disruption of the syndesmosis and loss of tibiotalar congruity.
Core principle
The aim of treatment is to restore fibular length and rotation, medial stability, posterior plafond congruity and syndesmotic stability, thereby recreating a congruent ankle mortise.
Relevant Anatomy
- Lateral malleolus: distal fibula; maintains talar alignment and syndesmotic relationship.
- Medial malleolus: attachment of superficial and deep deltoid ligament components.
- Posterior malleolus: posterior distal tibial plafond; attachment site of the posterior inferior tibiofibular ligament (PITFL).
- Syndesmosis: AITFL, interosseous ligament/membrane and PITFL complex.
Injury to the posterior malleolus therefore has implications not only for the articular surface but also for syndesmotic stability.
A. Mechanism of Trimalleolar Fracture
Trimalleolar fractures usually occur from a rotational injury in which sequential failure of osseous and ligamentous structures occurs around the ankle.
The exact sequence depends on the position of the foot and direction of deforming force. The commonest Lauge-Hansen patterns associated with…