Ankle fractures involving the anterolateral distal tibia: medium-term clinical results of 50 cases.

Purpose: The anterolateral distal tibial rim (anterior malleolus, AM) is frequently fractured in malleolar fractures. The aim of this study was to evaluate the medium-term outcomes of malleolar fractures involving the AM.

Methods: Among 100 patients with AM fractures that were treated over a 10-year period, 50 patients were available for follow-up. Outcome was assessed with the Olerud Molander Ankle Score (OMAS), the Foot Function Index (FFI-D), the EuroQol (EQ)-5D-5L Index, the EQ-VAS and the AOFAS Ankle-Hindfoot Score. Type 1 AM fractures (bony syndesmotic avulsions) were fixed surgically with either a suture anchor or a transosseous suture in 11 of 22 cases (50%). Among type 2 AM fractures (with incisura and joint involvement), 68% were treated surgically with screw fixation. All three type 3 AM fractures (anterolateral tibial plafond impaction) were treated surgically with either screw or plate fixation.

Results: At follow-up, the median OMAS was 75, the FFI-D 19, the EQ-5D-5L-Index 0.88, the EQ-VAS 70, and the AOFAS score 93. Assuming that the fracture severity increases from Supination-External Rotation to Pronation-External Rotation and Pronation-Abduction injuries, the AOFAS score (p < 0.001), OMAS score (p = 0.009), and FFI-D (p = 0.041) all showed a significantly inferior clinical outcome with increasing fracture severity. Patients who required surgical revision (n = 5) showed a significantly inferior outcome with the OMAS (p = 0.019).

Conclusions: A differentiated treatment protocol tailored to dislocation, size, incisura involvement and joint impaction leads to favourable outcomes in complex malleolar fractures involving the AM. More data are needed on the outcome of AM fractures that are still commonly underestimated and overlooked.