Clinical and radiological comparisons of isolated posterior malleolar fractures treated surgically and conservatively.

Background: Isolated posterior malleolar (PM) fractures are rare fractures without consensus regarding treatment decisions and functional outcomes. The study aims to compare the clinical and radiological results of patients treated surgically or conservatively for isolated PM fractures.

Methods: The study included 30 patients who presented with an isolated PM fracture and were treated conservatively (n = 15) or with surgery (n = 15). The two groups were compared regarding demographic data, clinical results, and radiological outcomes. The effect of PM fragment size covering less than or more than 25% of the joint surface on clinical and radiological outcomes was also evaluated.

Results: The Ankle Fracture Scoring System (AFSS), Visual Analog Scale (VAS), and satisfaction scores of the patients in the surgical group were determined to be better than those of the conservatively treated group (p = 0.015, p = 0.029, p = 0.021). A higher rate of osteochondral lesion (OCL) in the talus was observed in the surgical group (p = 0.007). In the patients with fracture size > 25%, the AFSS-1, VAS, and patient satisfaction scores were found to be better in the surgical group than in the conservative group (p = 0.004, p = 0.036, p = 0.014), with no difference determined between the groups in respect of the OCL rate.

Conclusion: Independently of the fracture size, surgical treatment of patients with PM fracture provides better clinical results. It does not change the joint ROM however may increase the OCL rate. While surgical treatment does not affect the clinical results in patients with a fracture size smaller than 25%, it positively affects the clinical results in patients with a larger fracture size.

Level of evidence: Level IV, retrospective cohort study.