Advantages of ultrasound identification of the distal insertion of the calcaneofibular ligament during ligament reconstructions

INTRODUCTION

In lateral ankle instability, anatomical ligament reconstructions are generally performed using arthroscopy. The ligament graft is passed through the talar, fibular and calcaneal tunnels, reconstructing the anterior talofibular and calcaneofibular (CFL) bundles. However, the calcaneal insertion of the CFL needs to be performed in an extra-articular fashion, and cannot be carried out under arthroscopy, thus requiring specific anatomical landmarks. For obtaining these landmarks, methods based on radiography or surface anatomy have already been described but can only offer an approximate identification of the actual CFL anatomical insertion point. In contrast, an ultrasound technique allows direct visualization of the insertion point and of the sural nerve that may be injured during surgery. Our study aimed to assess the reliability and accuracy of ultrasound visualization when performing calcaneal insertion of the CFL with specific monitoring of the sural nerve.

MATERIALS AND METHODS

Our anatomical study was carried out on 15 ankles available from a body donation program. Ultrasound identification of the sural nerve was obtained first with injection of dye. A needle was positioned at the level of the calcaneal insertion of the CFL. After dissection, in all the ankles, the dye was in contact with the sural nerve and the needle was located in the calcaneal insertion area of the CFL. The mean distance between the sural nerve and the needle was 4.8 mm (range 3-7 mm).

DISCUSSION AND CONCLUSION

A pre- or intra-operative ultrasound technique is a simple and reliable means for obtaining anatomical landmarks when drilling the calcaneal tunnel for ligament reconstruction of the lateral plane of the ankle. This tunnel should preferably be drilled obliquely from the heel towards the subtalar joint (1 h-3 h direction on an ultrasound cross section), which preserves a maximum distance from the sural nerve for safety purposes, while allowing an accurate anatomical positioning of the osseous tunnel.

Calcaneal fracture with a concomitant unstable subtalar dislocation: A case report

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Subtalar dislocation is a rare injury with post reduction instability being even rarer.

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Rarity is attributed to the presence of a strong ligament connecting the talus and the calcaneus.

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They occur more frequently in men than in women and predominately affect people in their mid-30 s.

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Our case highlighted the importance of the calcaneo-fibular ligament as a subtalar stabilizer.

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Our case is unique in using a synthetic graft to reconstruct the calcaneofibular ligament.

Background

Traumatic dislocation of the subtalar joint is an infrequently occurring injury, first described by DuFaurest in 1811. They were later on classified by Broca as medial, lateral, posterior and anterior dislocations based on the direction of the dislocation.

Case report

We present a case of a 30 year old male who presented after a 5 m height fall and direct right foot trauma. Investigations done in the emergency department revealed a right subtalar lateral dislocation with associated calcaneal intraarticular displaced fracture. Open reduction internal fixation of the calcaneal fracture was decided alongside with reduction of the subtalar joint. Intraoperatively the subtalar reduction was totally unstable due to the deficiency of the lateral collateral ligament. A decision of reconstruction of the calcaneofibular ligament using a synthetic ligament was taken. This reconstruction resulted in an adequate intraoperative stability of the subtalar joint. On a 2 year follow up the patient was asymptomatic with no residual subtalar instability.

Discussion

These injuries must be suspected after high energy trauma or twisting forces in the foot. They occur more frequently in men than in women and predominately affect people in their mid-30 s. Our case is unique in that the reconstruction of the calcaneofibular ligament was done using a synthetic graft to stabilize an acute unstable subtalar joint dislocation.

Conclusion

Subtalar dislocation is a rare injury with post reduction instability being even rarer. Care has to be taken not to overlook the frequently associated bony injuries, due to their impact on treatment decision and prognosis.

Arthroscopic anatomical reconstruction of the lateral ankle ligaments: A technical simplification

Anatomical reconstruction of the lateral ankle ligaments has become a pivotal component of the treatment strategy for chronic ankle instability. The recently described arthroscopic version of this procedure is indispensable to ensure that concomitant lesions are appropriately managed, yet remains technically demanding. Here, we describe a simplified variant involving percutaneous creation of the calcaneal tunnel for the distal attachment of the calcaneo-fibular ligament. The rationale for this technical stratagem was provided by a preliminary cadaver study that demonstrated a correlation between the lateral malleolus and the distal footprint of the calcaneo-fibular ligament. The main objectives are simplification of the operative technique and decreased injury to tissues whose function is crucial to the recovery of proprioception.