The treatment options for posterior malleolar fractures in tibial spiral fractures

Purpose: The posterior malleolar fracture (PMF) in tibial spiral fractures are a common type of complication that occurs in tibial fractures. However, the indication of fixation for posterior fractures is still under debate and varies between different surgeons'. It is not unusual to find the smaller PMF (<25%), which could be treated conservatively within guidelines, treated with internal fixation in clinic. The aim of this study is to evaluate the clinical outcomes of tibial spiral fractures with PMF and provide proper guidance for the treatment of this special fracture.

Methods: A total of 284 cases of spiral fractures combined with PMF were collected and analyzed. Demographic data, fragment size (classified by 25% involvement of ankle joint), time to weight-bearing and functional scores post-operatively were recorded. The ankle-hindfoot scale of the American Orthopaedic Foot and Ankle Society (AOFAS), a visual analogue scale (VAS) pain score, assessment of dorsiflexion restriction and arthritis scale were used as the main evaluations.

Results: Forty patients with a larger PMF (≥25%) and 72 with smaller ones (<25%) were fixed and categorized as the fixation group (FG). In the nonfixation group (NG), the corresponding numbers were four and 168 patients respectively. A total of 279 PMF were classified as large posterolateral triangular fragment carrying the posterior half of the fibular notch and intra-incisural posterolateral fragment involving one-fourth to one-third of the fibular notch. However, no obvious differences were observed in terms of the clinical outcomes in PMF involving one-fourth to one-third of the fibular notch. In the treatment of smaller PMF (<25%) of this type, there were no obvious differences in the functional outcomes between fixed (SF) and nonfixed PMF (SN).

Conclusions: Many patients with smaller PMFs were fixated, but functional outcomes of SF were not better than those of SN. There is no need to emphasize other factors guiding the treatment of PMF involving one-fourth to one-third of the fibular notch in spiral fractures. The traditional size of PMF may be only enough to guide the treatment of spiral fracture with PMF. But other types of PMF should still be treated considering morphology and fragment simultaneously.