Posterior malleolar ankle fractures

Area of Science:

• Orthopedic Surgery
• Traumatology
• Radiology

Background:

• Posterior malleolar ankle fractures (PMAFs) pose treatment challenges.
• Current treatment decisions often prioritize posterior malleolar fragment size.
• The importance of fracture morphology in rotational PMAFs requires further investigation.

Purpose of the Study:

• To test the hypothesis that fracture morphology is more critical than fragment size in rotational PMAFs.
• To identify specific predictors of outcome for different PMAF subtypes.
• To challenge the conventional focus on fragment size for surgical decision-making.

Main Methods:

• Prospective cohort study of 70 operatively treated rotational PMAFs.
• Classification into Haraguchi Types I, II, and III based on fracture morphology.
• Quantitative 3D-CT (Q3DCT) for assessing reduction quality (articular involvement, gap, step-off, displacement).
• Correlation of Q3DCT measurements and morphology with Foot and Ankle Outcome Score (FAOS) at 2-year follow-up.

Main Results:

• Fracture morphology and fragment size were initially associated with FAOS.
• Multivariate analysis revealed fracture morphology (p=0.001) and residual intra-articular gap (p=0.009) as significant predictors.
• Haraguchi Type II PMAFs showed poorer FAOS scores compared to Types I and III.
• Independent predictors varied by type: step-off for Type I, no Q3DCT measures for Type II, and syndesmotic reduction quality for Type III.

Conclusions:

• Rotational PMAFs represent distinct entities based on morphology, each with unique outcome predictors.
• Treatment decisions for PMAFs should be guided by fracture morphology rather than fragment size.
• Further refinement of treatment strategies is needed to determine optimal fixation for specific morphological subtypes.