Influence of posterior malleolar fragment morphology on the outcomes of trimalleolar fractures
Abstract
A strategic re-evaluation of Posterior Malleolus Fractures (PMF) shifting focus from fragment size to morphology. The study establishes the Haraguchi classification as a critical predictor of functional AOFAS scores.
Morphology Over Size: The Haraguchi Factor
Key Finding
"Patients with Haraguchi Type 1 (posterolateral-oblique) fractures achieved significantly superior functional outcomes (AOFAS scores) compared to complex Type 2 injuries (p = 0.038)."
Background: Historical dogma dictated fixation of posterior malleolus fractures based solely on size (> 25% of articular surface). This simplistic metric failed to account for syndesmotic stability and joint impaction. This study investigated whether fracture morphology—specifically the Haraguchi classification—is a more accurate determinant of long-term functional recovery.
Methods: A meta-analysis of 11 studies involving 597 patients with trimalleolar fractures. The authors correlated fracture patterns (Haraguchi Type 1: posterolateral vs. Type 2: medial extension) with American Orthopaedic Foot and Ankle Society (AOFAS) scores. Statistical tools included univariate and multivariate meta-regression models to adjust for age and gender.
Results: The pooled mean AOFAS score was 87.43. Univariate analysis revealed a statistically significant positive correlation between Haraguchi Type 1 fractures and higher AOFAS scores (p = 0.031). Conversely, Haraguchi Type 2 fractures (involving the fibular notch and medial malleolus) trended toward inferior outcomes. Multivariate analysis confirmed Type 1 morphology as an independent predictor of superior function (p = 0.038).
Conclusion: Fracture morphology is a superior prognosticator to fragment size. Haraguchi Type 2 fractures represent a distinct, high-energy injury pattern with inherently poorer prognosis, likely necessitating more aggressive or specialized fixation strategies compared to the more benign Type 1 injuries.