[Triplane Fractures of the Distal Tibial Epiphysis - Contributions of CT Scans to Indication and Planning of Osteosynthesis].

PURPOSE OF THE STUDY The triplane fracture of the distal tibial epiphysis is characterised by the fracture line in typical three planes which can, however, differ case by case. The authors use the CT imaging as the perfect examination method to determine the nature of the fracture to plan the osteosynthesis. MATERIAL AND METHODS In the five-year retrospective study of a group of patients treated at their own department in the period 2011-2015 the authors assess a total of 55 patients with a triplane fracture. The radiograph, the CT scan and the specific therapeutic process are evaluated. Regarding the imaging methods, they focus on the fracture line, the number of fragments and the size of the dorsal metaphyseal fragment. As concerns the method of treatment, they zero in on the indication for osteosynthesis and the number and location of used implants. RESULTS The authors present a total of nine different treatment options of the triplane fracture of distal tibial epiphysis. Of 55 followedup patients, in seventeen cases (30.9%) conservative treatment was opted for, in seven cases (12.7%) a reduction under general anaesthesia was an adequate option, whereas in the remaining thirty-one cases (56.4%) an osteosynthesis had to be performed. In the group with osteosynthesis, in altogether twenty cases (64.5%) only a single implant was used: of which in twelve cases it was transepiphyseal, in eight cases transmetaphyseal. In the other eight cases (25.8%) two implants were used, one metaphyseal and one epiphyseal. In three remaining patients (9.7%) two implants were introduced, both into the metaphysis. DISCUSSION The world literature has been referring to the importance of CT scan in relation to the triplane fracture of the distal tibial epiphysis since 1980s. Some papers have only highlighted the necessity of the CT scan for the examination of a complex ankle injury, covering also the triplane fracture, while in majority of injuries involving the distal tibia region a common X-ray examination suffices;also mentioned has been its importance for determining the number of fragments, or in some papers also for preoperative planning. At our department, in correlation with the majority of authors, we routinely use two basic projections (AP view and lateral view) to examine the ankle. In the case of suspected intraarticular fracture, both the mortise views (internal and external) are added. The CT scan is a standard procedure used at our department for confirmed triplane fractures. In severely displaced fractures we recommend to perform a CT scan only after the closed reduction of fragments under general anaesthesia. CONCLUSIONS An X-ray obtained from 4 views is a standard examination in diagnosing a triplane fracture. A CT scan than makes it possible to precisely locate the fracture line, to determine the size of fragments and to plan the optimal placement of osteosynthetic material. Key words: tibial fractures, distal tibia fractures, paediatric fractures, triplane fracture, physeal fracture, CT imaging, minimally invasive osteosynthesis, treatment of distal tibia, osteosynthesis planning.