The Intercalary Fragment in Posterior Malleolus Fractures: Characterization and Significance

CATEGORY: Trauma INTRODUCTION/PURPOSE: Methods of fixation in ankle fractures involving the posterior malleolus have become increasingly scrutinized. With the increase in computed tomography (CT), an intercalary fracture fragment (ICF) adjacent to the posterior malleolus has often been described. Treatment of this intercalary comminution remains controversial. The primary goal of this study was to compare clinical and radiographic outcomes in patients who had direct reduction and fixation of this fragment compared to those where the ICF was removed or not reduced prior to posterior malleolus fixation. METHODS: This retrospective study included 249 trimalleolar and posterior pilon ankle fractures grouped into those who had the ICF reduced and fixed (n=74) and those where the ICF was not directly addressed or excised (n=175). CT scans were evaluated for size and location of the ICF. Demographic, radiographic and intraoperative variables were collected and analyzed. The Kellgren and Lawrence classification system was utilized to grade severity of post-traumatic arthritis during the follow up period. Chart review was performed assessing time to weightbearing, repeat surgeries and post-operative complications. RESULTS: For the group which had the ICF reduced and fixed, follow up radiographs demonstrated significantly worse Kellgren- Lawrence scores compared to the group that did not specifically reduce the ICF (p< 0.05). There was also a higher rate of repeat surgery in the group which had the ICF fixed, although not meeting statistical significance. There were no differences in size or location of the ICF fragment between groups. The average overall time to weightbearing amongst all patients was 9.7 +- 3.8 weeks. There was no significant difference between time to weightbearing between groups (p = 0.6). There was no significant difference in need for secondary surgeries or post-operative deep and superfical infections. CONCLUSION: With the widespread utilization of CT-scans for preoperative planning of ankle fractures involving the posterior malleolus, there has been greater discussion surrounding the optimal management of the ICF when present. In our study, the primary aim was to explore radiographic changes in patients after direct reduction and fixation of this ICF compared to those without ICF fixation. We demonstrated significantly worse radiographic outcomes following attempted direct reduction and fixation of the ICF. Our results suggest that while concentric joint reduction and syndesmosis stabilization are of utmost importance, attempting to reduce and fix the ICF may lead to worse radiographic outcomes.