Fibular head transfixion wire and its relationship to common peroneal nerve: cadaveric analysis

Abstract

Proximal tibio-fibular joint is routinely stabilised during leg lengthening, peri-articular fractures and deformity corrections of tibia. Potential injury to the common peroneal nerve at the level of the fibula head/neck junction during wire insertion is a recognised complication. Previous studies have mapped the course of the common peroneal nerve and its branches at the level of the fibular head, and guidelines are published regarding placement of proximal tibial wires. This study aims to relate the course of the common peroneal nerve to the placement of a lateral insertion fibula head transfixion wire. Standard 1.8-mm Ilizarov 'olive' wires were inserted in the fibula head of 10 un-embalmed cadaveric knees. Wires were inserted percutaneously to the fibula head using surface anatomy landmarks and palpation technique. The course of the common peroneal nerve was then dissected. Distances from wire entry point to the course of the common peroneal nerve were measured post-wire insertion. The mean distance of the common peroneal nerve from the anterior aspect of the broadest point of the fibular head was 24.5 mm (range 14.2-37.7 mm). Common peroneal nerve was seen to cross the neck of fibula at a mean distance of 34.8 mm from the tip of fibula (range 21.5-44.3 mm). Wire placement was found to be on average, 52 % of the maximal AP diameter of the fibula head and 64 % of the distance from tip of fibula to the point of nerve crossing fibula neck. When inserting a fibula head transfixion wire, care must be taken not to place wire entry point too distal or posterior on the fibula head. Observing a safe zone in the anterior half of the proximal 20 mm of the fibula head would avoid injury to the nerve. In cases where palpation of fibula is difficult due to patient habitus, we recommend consideration of the use of fluoroscopic guidance during wire transfixion of the proximal tibio-fibular articulation to avoid wire insertion too distally and subsequent potential nerve injury.

Keywords: Anatomy; Frame; Ilizarov; Limb lengthening; Peroneal nerve; Proximal tibial fractures.

Fig. 1

Demonstrating the lateral approach centred on the fibula. The photograph shows the wire in the fibula and the nerve lying posteriorly to the fibula

Fig. 2

Demonstration of the nerve released at point which it crosses the fibula neck but the attachments are not released to obtain accurate measurements

Fig. 3

Demonstration of the specimen in which the wire had been inserted posteriorly and distally near the fibula neck. The wire was touching the peroneal nerve as it was lying at the posterior edge of the fibula; however, although slightly indenting the nerve, it was not penetrating it. The discolouration seen in the specimen in this picture is from a previous study which had injected dye into the knee joint and dye had diffused into surrounding tissues. The previous study had no effect on the results of this study (colour figure online)

Fig. 4

Illustration demonstrating the area recommended for insertion of the wire in the coronal plane. The yellow lines show the range of the nerve crossing the fibula neck measured from the tip of the fibula, range 21.5–44.3 mm. Based on the findings in this study, we recommend that proximal fibula head wires should be inserted no further than 2 cm distal to the tip of the fibular head and aim slightly anterior in the fibula head in sagittal plane at the level of its maximal diameter, (patchwork area) (colour figure online)

Fig. 5

Illustration demonstrating the area recommended for insertion of the wire in the sagittal and axial planes