Medial Wall Blowout Fractures of the Ankle: - Novel Injury Pattern Classifications and Radiological Outcomes

Purpose or Learning Objective: Medial wall blowout (MWB) fractures of the ankle have not previously been classified or described in the literature. We Our aim in this study was to analyzed the morphology of MWBmedial wall blowout fractures and their radiological outcomes. We also sought A secondary aim was to identify if there was any specific pattern of injury at risk of non-union or malreduction.

Methods or Background: Patients who had undergone surgical fixation of their medial malleolar fracture were identified from 2012 to 2022, using electronic patient records. Analysis of their pre-operative, intra-operative, and post-operative radiographs was performed to determine the initial type of injury and then radiological outcomes relating to non-union and malunion. The MWB fracture fragments were characterized into three typesgroups: type 1, fracture was observed as an anteromedial wall fragmentation;. Type 2, fractures consisted of posteromedial wall fragmentation; and. Type 3, fractures consisted of both anteromedial and posteromedial wall fragmentation with medial joint impaction.

Results or Findings: A total of 653 patients were identified across a 10-year period with medial malleolar fractures. Of these, 35 had MWB fractures (5.36%) identified with computed tomographyCT imaging. There were 12 type 1 fractures (34.29%), 7 type 2 fractures (20.00%), and 16 type 3 fractures (45.71%). All fractures underwent open fixation, with type 1 fractures having a greater percentage of screw fixations compared with type 2 and type 3 (66.67% versuss 28.57% versusvs 43.75%). There were a similar number of malreductions in type 2 and 3 fractures, although the type 2 fractures had a much higher rate of non-union (57.14% versusvs 16.67% and 18.75%).

Conclusion: We observed that the MWBmedial wall blowout fractures have a predictable pattern, that was which have not been previously described. The posteromedial type has a higher rate of non-union, which may be due to the proximity of the tibialis posterior tendon and association with posterior malleolar fractures. The rotational mechanism is either internal or external rotation for types 1 and 2, whereasn the type 3 is akin to the medial pilon, produced in abduction. The awareness of these ankle injury patterns may help radiologists and surgeons identify patients who are at a potentially increased risk of mal-union and would benefit from closer evaluation.

 

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Publication History

Article published online:
22 May 2024