A calcaneal tunnel for CFL reconstruction should be directed to the posterior inferior medial edge of the calcaneal tuberosity

Abstract

Purpose Anatomical reconstruction of the calcaneoibular ligament (CFL) is a common technique to treat chronic lateral ankle instability. A bone tunnel is used to ix the graft in the calcaneus. The purpose of this study is to provide some recommendations about tunnel entrance and tunnel direction based on anatomical landmarks. Methods The study consisted of two parts. The irst part assessed the lateral tunnel entrance for location and safety. The second part addressed the tunnel direction and safety upon exiting the calcaneum on the medial side. In the irst part, 29 specimens were used to locate the anatomical insertion of the CFL based on the intersection of two lines related to the ibular axis and speciic landmarks on the lateral malleolus. In the second part, 22 specimens were dissected to determine the position of the neurovascular structures at risk during tunnel drilling. Therefore, a method based on four imaginary squares using external anatomical landmarks was developed. Results For the tunnel entrance on the lateral side, the mean distance to the centre of the CFL footprint was 2.8 ± 3.0 mm (0-10.4 mm). The mean distance between both observers was 4.2 ± 3.2 mm (0-10.3 mm). The mean distance to the sural nerve was 1.4 ± 2 mm (0-5.8 mm). The mean distance to the peroneal tendons was 7.3 ± 3.1 mm (1.2-12.4 mm). For the tunnel exit on the medial side, the two anterior squares always contained the neurovascular bundle. A safe zone without important neurovascular structures was found and corresponded to the two posterior squares. Conclusion Lateral landmarks enabled to locate the CFL footprint. Precautions should be taken to protect the nearby sural nerve. A safe zone on the medial side could be determined to guide safe tunnel direction. A calcaneal tunnel should be directed to the posterior inferior medial edge of the calcaneal tuberosity.

Arthroscopic and Open Procedures Result in Similar Calcaneal Tunnels for Anatomical Reconstruction of Lateral Ankle Ligaments

“…According to the measurements of previous studies, 13 , 15 , 17 , 18 , 19 , 20 , 21 radiographic parameters were measured and compared on lateral ankle radiographs to determine the reliability and reproducibility of calcaneal bone tunnels in each group. For radiographic viewing and measuring, we used the GE Centricity Enterprise Web 3 (GE Medical Systems) image system with magnification rate of 2.…”

“…The following parameters were measured ( Fig 2 ): 1) CFL to the subtalar joint (h): CFL bone tunnel to the midpoint of the lateral border of the posterior facet of the subtalar joint 19 ; 2) CFL to calcaneal superior edge (d): CFL bone tunnel to the superior edge of the calcaneal tubercle 18 ; 3) CFL to fibular tip ( C to F ): CFL bone tunnel to the fibular tip 15 ; 4) Angle with fibula (θ): Angle between the line from the CFL bone tunnel to the fibular tip and the line of fibula longitudinal axis 20 ; 5) CFL to the cross point of the fibular and tangential line of the FOT ( D ): the CFL bone tunnel to the cross point of the line of the fibular posterior cortex and the line of 45° angle passed through the anteroinferior part of the lateral malleolus (corresponding to the FOT) 13 ; 6) CFL to the cross point ( A ) of the tangential lines of the talar posterior edge and deepest point of the subtalar joint: CFL bone tunnel to the cross point between the vertical line tangential to the posterior convexity of the talus and the perpendicular line tangential to the deepest concavity of the subtalar joint 17 ; and 7) CFL to the cross point ( B ) of the CFL bone tunnel to the cross point of the line 1 cm of the fibular posterior cortex and the perpendicular line 1 cm to the fibular tip. 21

Fig 2 Anatomic parameters for the distal insertion of the calcaneofibular ligament (CFL).

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“… 11 , 12 Many studies have provided anatomic references for the distal insertion of the calcaneofibular ligament (CFL) for CFL reconstruction. 13 , 14 , 15 According to those studies, several anatomical measurements were used to locate the calcaneal footprint of the CFL, but there was still a lack of consensus. 14 , 15 , 16 , 17 …”

Endoscopic Approach to Ligament Repair and Reconstruction for Chronic Ankle Instability

“…The wire is then over-drilled to a 6 mm diameter to create a calcaneal tunnel from the calcaneal footprint to the anterior medial edge of the calcaneal tuberosity. 28 (Fig. 10)…”

“…A guide pin is then advanced perpendicular to the coronal axis of the calcaneus. The wire is then over-drilled to a 6 mm diameter to create a calcaneal tunnel from the calcaneal footprint to the anterior medial edge of the calcaneal tuberosity 28. (Fig.…”