Outcomes of posterior malleolar fractures with intra-articular impacted fragment.

Introduction: An intra-articular impacted fragment (IAIF) could lead to articular incongruity and malreduction in ankle fractures with posterior malleolar fractures (PMFs). No studies have been conducted to determine whether the presence of IAIF affects the outcome of ankle fractures with PMF. The aim of our retrospective study was to evaluate the effect of IAIF on postoperative outcomes in PMF and analyze the relationship between area of IAIF and outcomes.

Materials And Methods: We conducted a retrospective study of patients with a posterior malleolar fractures between June 2012 and January 2019 with a minimum follow-up of 2 years. Results of the Olerud-Molander ankle score (OMAS), EuroQol-5D (EQ-5D) index, EQ-5D visual analog scale (VAS), AOFAS (American orthopedic foot and ankle society ankle-hindfoot scale), visual analog scale (VAS) pain score and overall patient satisfaction scale were recorded. Outcomes of the PMF with IAIF group and PMF without IAIF group were compared. Sub-group analysis was given emphasis on the A > 40 mm group and A < 40 mm group in PMF with IAIF.

Results: A total of 128 patients were included in the study, consisting of 86 patients with IAIF and 42 patients without IAIF. Regarding the osteoarthritis grade (> 1,  ≤ 1), the differences werestatistically significant between the two groups (P = 0.044). The risk of articular malreduction was higher in the PMF with IAIF group than in the PMF without IAIF group (P = 0.035). Osteoarthritis grade (> 1,  ≤ 1) was closely related to articular malreduction (P < 0.001). There were 51 patients in the A > 40 mm group and 35 patients in the A < 40 mm group of 86 patients in PMF with IAIF. There were statistically significant differences in trimalleolar fracture (P = 0.004), malreduction (P = 0.022), osteoarthritis grade (> 1,  ≤ 1; P = 0.027), EQ-5D VAS score (P = 0.031), and AOFAS score (P = 0.047) between the subgroups.

Conclusion: The incidence of IAIF is associated with the area of the posterior malleolar fragment. Articular malreduction can lead to post-traumatic osteoarthritis, while IAIF is an important element for the quality of reduction, which is more likely to lead to articular malreduction. IAIF should be reduced if A is over 40 mm. Otherwise, the patient will suffer a poor prognosis and post-traumatic osteoarthritis. Therefore, ankle fractures with PMF should undergo a CT scan preoperatively in order for providers to optimal treatment protocols.

Level Of Evidence: Level III.