Sinus tarsi approach to the calcaneus

This approach is used for fixation of displaced intraarticular calcaneal fractures. It provides better visualization of the anterior aspect of the calcaneum compared to the extended lateral approach and the lateral extensile approach.

Note: The sinus tarsi approach only provides limited fracture visualization of the posterior part of the calcaneum. In particular, the body fragment and primary fracture line are not directly visualized. However, it has been shown to provide a similar exposure of the posterior facet of the subtalar joint as compared to the extended lateral approach or lateral extensile approach.

Due to this limitation of fracture exposure, it is important to have an adjunctive method, eg, external fixator, for reducing the primary fracture line.

$Sinus tarsi approach to the calcaneus for displaced intraarticular fracture fixation with adjunct reduction$

This illustration shows the areas of the calcaneus that are visualized through this surgical approach.

Sinus tarsi approach to the calcaneus showing calcaneus areas visualized through the approach

Neural anatomy

Take care to protect the sural nerve.

Sinus tarsi approach to the calcaneus with care to protect the sural nerve

Vascular supply

The lateral calcaneal artery is responsible for most of the blood supply to this area.

If there is a need to extend the sinus tarsi approach proximally, one should avoid dissection through the deep portion of the superior peroneal retinaculum. The lateral calcaneal artery will then be protected, thus preserving the blood supply to the lateral calcaneal skin and soft tissues.

Sinus tarsi approach to the calcaneus preserving lateral calcaneal artery blood supply

Ligaments, tendons, and muscles

The peroneal tendons are on the lateral side of the calcaneus. Note the position of the peroneal retinaculum, and the lateral collateral ligament.

Note: Peroneal subluxation is common in a calcaneal fracture and usually resolves following satisfactory fracture reduction.

Sinus tarsi approach to the calcaneus showing peroneal tendons, retinaculum, and lateral collateral ligament

Correct timing of surgery is an important factor in preventing local wound complication. Too early surgery may lead to skin necrosis. Therefore, patience is required to optimize the local surgical environment.

Skin blisters should be observed and carefully protected.

The image shows a foot 3 days after serious trauma, which is inappropriate for surgery.

The return of skin wrinkles to the lateral side of the foot should be used as a guide for the timing of surgery.

The image shows a foot 14 days after injury appropriate for surgery, with the “wrinkle sign” present.

Sinus tarsi approach to the calcaneus showing wrinkle sign guiding timing of surgery

This approach runs from the tip of the fibula distally to the base of the fourth metatarsal base. The peroneal tendons lie inferior and posterior to the incision.

Note: The exposure may be compromised by improperly placed incision. Intraoperative imaging may help to precisely position the incision over the subtalar joint.

Start the incision at the tip of the fibula and extend it distally, through the skin …

Sinus tarsi approach to the calcaneus incision from fibula tip to fourth metatarsal base

… and then through the deep fascia. Protect the tendons and the sural nerve inferiorly.

The exact orientation and length of the incision may be adjusted depending on the fracture pattern.

Part of the extensor digitorum brevis may be reflected.

Sinus tarsi approach to the calcaneus through deep fascia; protect tendons and sural nerve

Enter the joint capsule and expose the subtalar joint.

This small incision allows for direct visualization of the subtalar joint. The quality of reduction can be assessed. The internal fixation construct can be inserted through this incision; it can be lengthened as needed.

Subtalar arthroscopy can assist in accurate joint reduction.