[Relationship between the cause and length of posterior malleolar fragment and treatment strategies for posterior malleolar fracture in adult patients].

Objective: To explore the relationship between the causes and length of posterior malleolar fragment and treatment strategies of adult patients with three types of ankle joint injury.

Methods: The investigators recruited 233 cases of type C injury, 35 cases of type B injury and 91 cases of type A injury. Type A injury referred to simple ankle joint fracture with the involvement of posterior malleolar fragment. Type B injury tibial shaft fracture with ipsilateral ankle joint fracture. And posterior malleolar fracture line was the continuity of tibial shaft fracture line. Type C injury appeared similar to Type B injury, but tibial and malleolar fracture lines were not continued. The ratio between the length of posterior malleolar articular and the total length of articular surface was calculated in theses three types of injuries in sagittal CT scan slice. Different treatment regimens were used to manage the posterior malleolar fractures. And visual analogue score (VAS) was introduced to assess the therapeutic outcomes.

Results: The ratio between the length of posterior malleolar articular and the total length of articular surface decreased from Type A to Type C (χ(2) = 187.453, P = 0.0000). The ratio was (34 ± 15)% for Type A, (30 ± 9)% for Type B and (12 ± 10)% for Type C. A follow-up study was performed in Type A injury (n = 58), Type B injury (n = 31) and Type C injury (n = 167) at 12 months. According to VAS score, there was no significant difference between the patients undergoing fixation and not (all P > 0.05).

Conclusion: Different causes of posterior malleolar fracture results in different sizes of posterior malleolar fragment and strategies of treatment. The anatomic reduction of posterior malleolar fragment remains a key aspect of achieving satisfactory outcomes in all kinds of injury.