A Retrospective Study of the Clinical Outcomes of Pilon Variant Posterior Malleolar Fracture involving Intra-Articular Impacted Fragments

Abstract

INTRODUCTION Intra-articular impacted fragment (IAIF) is commonly found in the Pilon variant posterior malleolar (PVPM) fracture. Poor quality of reduction may result in articular incongruity, leading to ankle function impairment and ultimately traumatic arthritis. However, the debating remains on if the IAIF must be reduced, and how the presence or malreduction of the IAIF influences the prognosis in PVPM fractures. This retrospective study is to evaluate the prognostic effect of the IAIF reduction in the PVPM fractures. METHODS We studied 22 patients with PVPM fractures admitted to our hospital between June 2020 and June 2021, who were treated with open surgery and followed-up for 12 months retrospectively. The patients were divided into two groups: six patients without IAIF (No-IAIF group) and 16 patients with IAIF (IAIF group). Burwell-Charnley scoring system and ankle CT scan were used to evaluate the radiographic outcomes. At postoperative 12 months, American Orthopedic Foot and Ankle Score (AOFAS) was set as primary outcome. Visual Analog Scale (VAS) pain score, the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) were secondary outcomes and associated complications were recorded. Postoperative articular stepping ≥2mm or articular incongruity on the sagittal view of CT scans was considered “poor” reduction, otherwise “anatomical”. The study abided by the Declaration of Helsinki and is approved by Human Ethics Committee of our hospital. All persons gave their informed consent prior to their inclusion in the study. RESULTS The articular surface of five of six patients in No-IAIF group and eight of 16 patients in IAIF group were considered “anatomically” reduced. Statistical difference of AOFAS, SF-36 and VAS was found significant between the No-IAIF and IAIF groups at postoperative 12 months. In the fractures considered with “anatomical” reduction, significant difference was only seen in SF-36 between the patients with and without IAIF. Three of 22 patients received syndesmotic fixations. No difference of associated complications was noted. DISCUSSION The results of this study indicated that the short-term clinical effect was dependent of the presence the IAIF. Importantly, the reduction satisfactory was statistically associated with improved clinical outcomes at 12 months postoperatively. SIGNIFICANCE The presence of the IAIF negatively affect the clinical outcome and the anatomical reduction of the articular congruity will positively affect the prognosis of PVPM fracture.