[Risk of iatrogenic neurovascular damage by proximal 3-dimensional intramedullary nailing of the tibia]

The rate of clinically relevant neurovascular injuries after proximal intramedullary nailing of the tibia remains unclear. The anatomical risk of iatrogenic damage to these structures should be estimated in a prospective MRI examination.

A total of 99 consecutive patients were included in the study cohort. All patients underwent an MRI examination due to suspected intra-articular lesions of the knee joint. Examinations were performed at the Institute for Radiology at the Clinic of Worms. The MRI system used was a Philips Intera 1.0 Tesla (Philips, Böblingen, Deutschland). The distance of the neurovascular bundle (GNB) to the posterior tibial cortex was measured (dTK) to estimate the risk of bicortical drilling. The position of the GNB (pGNB) in the medial (+pGNB) and lateral (-pGNB) directions was determined relative to the tibial head midline to estimate potential advantages of oblique or rotated insertion of the nail.

The mean distance between the posterior tibial cortex and the GNB was 11.54 mm (range 4-21 mm standard deviation 3.42 mm). In relation to the tibia head midline, the maximal lateral position was determined as 23 mm and maximal medial position was 6 mm. In 9 cases the GNB was found medially, in 12 cases in the midline and in 69 cases laterally. The mean lateral position of the GNB was 6.03 mm.

Triple proximal interlocking in tibial nailing procedures can be considered a safe procedure if care is taken with the correct operation technique and careful image intensification control of drilling procedures. A rotated nail insertion to avoid a strict anterior-posterior positioning of proximal interlocking screw is not to be recommended.