Injury of the Tibial Nutrient Artery Canal during External Fixation for Lower Extremity Fractures: A Computed Tomography Study

Abstract

The tibial nutrient artery (TNA) is the major diaphyseal artery of the tibia supplying two thirds of the inner osseous cortex. Hence, iatrogenic injury of the TNA endangers the integrity of the tibial blood supply and may compromise fracture healing. The incidence of its injury in the setting of external fixation for lower limb fractures has not been previously investigated. The aim of this study was to evaluate the incidence of TNA injury in the context of external fixation and to characterize the topography of the fixator pins in relation to the TNA canal (TNAC). Patients who underwent external fixation for distal femoral fractures and for tibial (proximal, shaft, and distal) fractures and had a postoperative computed tomography study were retrospectively included. The following parameters were retrieved: 1) Pin characteristics (orientation and cortical position of the pins), 2) The anatomic relationship between the TNAC and external fixation pin (topography above/below and at the level of the TNAC, and the distance between the pin and medial tibial plateau and/or the medial malleolus), and 3) The incidence of TNAC injury (complete/partial disruption of TNA lumen). A total of 105 patients with 214 tibial pins were analyzed. In 27 patients (26%), the TNAC was completely injured by the pins of the external fixator. In 13 patients (12%), the TNAC was partially injured. Of the 214 analyzed pins, 85 pins (40%) were located at the level of the TNAC (the TNAC and the pin are seen on the same axial slice). Most pins that were applied at the level of the TNAC belonged to a knee-bridging external fixator. Of those, ninety-three percent of the pins were anteromedially applied according to published surgical guidelines. Six percent of the pins were applied through the tibial crest and 1% anterolaterally. Of those 85 pins, 42 pins (49%) injured the TNAC at least partially. Based on the analyzed pins and the incidence of partial and complete injury of the TNAC, we observed that the tibial segment at which the tibial nutrient artery is endangered was located approximately (95% CI: 13–15 cm) from the medial tibia plateau and (95% CI: 22–25 cm) from the medial malleolus. Thus, TNAC injury by external fixation pins in the context of lower limb fractures can be considered common. Almost half of the pins applied at the middle third of the tibia injured the TNA, despite adherence to published surgical guidelines for external fixation. When possible, pin application at the middle third of tibia should be avoided to circumvent iatrogenic injury of the TNA and to safeguard tibial blood supply.

Method for generating transparent porcine tibia showing the intraosseous artery

“…At present, the commonly used clinical tibial fracture fixation instruments can easily cause damage to intraosseous blood vessels. According to a retrospective study of 105 patients with tibial fractures treated with external fixators by Almansour et al [ 25 ], at least 38% of the patients had damaged tibial nutrient arteries, which may be conservative given that damage to the nutrient arteries itself cannot be detected by computed tomography. This view is also supported by Brinker et al [ 26 ], who reported a similar situation in patients treated with tibial intramedullary nailing.…”

Functional and Radiological Outcome Analysis of Osteoperiosteal Decortication Flap in Nonunion of Tibia

“…is calls for some insight into the blood supply of diaphysis of the tibia. e major vascularity in the tibial diaphysis is by the tibial nutrient artery (TNA), which is responsible for supplying the inner two-third of the diaphyseal cortex [9]. e extraosseous blood supply of the tibial diaphysis is poor compared with the proximal and distal metaphysic [25].…”

“…Open surgical procedures disturb the soft tissue envelop surrounding the fracture, more so in the tibial diaphysis, which has already a precarious extraosseous blood supply [9]. e osteoperiosteal decortication flap technique effectively addresses this issue in the nonunion tibia and ensures an adequate biological environment at the nonunion site.…”

Method for generating transparent porcine tibia showing the intraosseous artery

“…At present, the commonly used clinical tibial fracture xation instruments can easily cause damage to intraosseous blood vessels. According to a retrospective study of 105 patients with tibial fractures treated with external xators by Almansour et al [19], at least 38% of the patients had damaged tibial nutrient arteries, which may be conservative given that damage to the nutrient arteries itself cannot be detected by computed tomography. This view is also supported by Brinker et al [20], who reported a similar situation in patients treated with tibial intramedullary nailing.…”