Operative Treatment of Quadrimalleolar and Quadrimalleolar-Equivalent Ankle Fractures: Radiographic and Clinical Outcomes Following Component-Based Operative Fixation

Background: Quadrimalleolar (QM) and quadrimalleolar-equivalent (QME) fractures expand the trimalleolar concept by adding an anterior osseous syndesmotic component (Chaput or Wagstaffe fragment). Outcomes after operative fixation remain incompletely defined. Methods: We retrospectively reviewed 36 consecutive patients (18 QM, 18 QME) who underwent open reduction and internal fixation between April 2019 and December 2024, with a minimum 12-month follow-up. All patients underwent a component-based operative treatment strategy comprising preoperative computed tomographic (CT) characterization of each malleolar and syndesmotic component, morphology-based management of anterior fragments, and intraoperative arthroscopic assessment of residual instability. Syndesmotic reduction was assessed on bilateral CT 1 cm proximal to the plafond using direct anterior and posterior differences, fibular translation, and fibular rotation, referenced to the contralateral ankle. Clinical outcomes included Olerud-Molander Ankle Score (OMAS) and visual analog scale (VAS). Results: Baseline demographics did not differ significantly between groups. QME injuries were predominantly SER (supination–external rotation) type IV/Weber B (94.4%), whereas QM showed an even distribution between SER and PER (pronation–external rotation) and between Weber B and C ( P = .01). No significant side-to-side differences were observed in any of the 4 parameters in either group at 1 year (all P > .05); given the limited sample size, these nonsignificant findings may be subject to a type II error. Intra- and interobserver reliabilities were excellent (intraclass correlation coefficient 0.901-0.988). Mean OMAS improved to 86.1 ± 6.8 (QM) and 85.3 ± 5.7 (QME); VAS decreased to 1.0 ± 0.7 in both (within-group P < .001; between-group P = .82). All fractures united; 3 minor wound complications resolved with local care. Conclusion: A component-based operative treatment strategy was safe and associated with maintained anatomic distal tibiofibular alignment and favorable short-term outcomes in both QM and QME. The absence of a control group precludes conclusions on clinical necessity or superiority, and combined evaluation of these biomechanically distinct patterns should be interpreted with caution. Level of Evidence: Level IV, retrospective comparative case series.