27 Lateral Malleolus/Bimalleolar Ankle Fractures

10.1055/b-0040-174150

27 Lateral Malleolus/Bimalleolar Ankle Fractures

Jonathan S. Markowitz, Philip K. Louie, and Ettore Vulcano

Summary

Ankle fractures are one of the most common fractures treated by orthopedic surgeons, with an incidence estimated to be 250,000 per year in the United States. ¹ The two most commonly used classification systems for ankle fractures are the Lauge-Hansen and AO classifications. The Lauge-Hansen classification system is based on a cadaveric study that stratified the mechanism of injury into different stages. The nomenclature is also dependent on the position of the foot and application of force to the ankle at the time of injury. The AO classification system classifies fractures based on the level of injury in relation to the syndesmosis: infrasyndesmotic (44A), transsyndesmotic (44B), and suprasyndesmotic (44C). Indications for operative treatment generally include any open fractures, talar displacement or instability, displaced isolated medial or lateral malleolar fractures, or bi-/tri-malleolar fracture patterns. Consideration on the timing of surgery is dependent on the stability of the fracture and the extent of the soft-tissue injuries. Open fractures often require irrigation and debridement at a minimum, and external fixator placement for instability in the setting of excessive soft-tissue compromise or swelling.

27.1 Preop

Initial imaging studies should include anteroposterior (AP), lateral, and mortise plain radiograph views of the injured ankle. Contralateral plain radiographs can be obtained on the contralateral ankle for operative planning and determining goals of correction.
Surgical table. Radiolucent table
Patient position.
- In the absence of a large posterior malleolus fragment, the patient is generally supine with feet at the end of the bed, bump under hip to get limb into neutral rotation and patella pointing toward ceiling. The distal limb is elevated with a bump or foam to allow for lateral intra-operative fluoroscopy (▶Fig. 27.1).
- If there is a posterior malleolus fracture that requires internal fixation, the patient can be placed prone or in a lateral position. In the setting of a concomitant lateral or medial malleolus fracture, the patient can remain prone with flaps elevated to address these fractures, or they can be flipped back to a supine position.

**Fig. 27.1** The photo demonstrates the injured leg on the operating room table. Note the pillow under the leg to facilitate access to the C-arm. A bump under the ipsilateral gluteus can help internally rotate the ankle to improve access to the lateral malleolus. Also, note the C-arm on the opposite side of the surgical extremity.

27.2 Approaches to Medial Malleolus—Anteromedial vs Posteromedial

27.2.1 Anteromedial Approach

Make a 3-cm curvilinear incision, over the anterior one-third of the medial malleolus in the direction of the middle of the distal tibia.
Dissection is carried down through the skin, subcutaneous fat, and fascia.
Identify and retract the long saphenous vein and the accompanying saphenous nerve, which lie at the anterior one-third of the medial malleolus or just anterior to it.
Expose the fracture site and free periosteum from the edges of the fracture in its entirety.
The posterior tibial tendon should be visualized to ensure that it remains intact.
If necessary, make a vertical incision at the anteromedial edge of the joint capsule to visualize the joint and dome of talus to evaluate for any talar impaction. If there is cartilage damage, microfracture can be performed in the injured region.

27.2.2 Posteromedial Approach

This approach is used for cases with posterior extension of a medial malleolar fracture, or if the patient has a posterior malleolus fracture that requires fixation in prone position, and would like to also address a concomitant medial malleolus fracture from the prone position.
Make a 10-cm longitudinal incision beginning 5-cm proximal to the medial malleolus on the posterior border of the tibia. Once past the posterior border of the medial malleolus, the incision should be curved anteriorly so that the distal incision edge is 5 cm from the medial malleolus.
Dissection is carried down through the skin, subcutaneous fat, and fascia.
At the distal portion of the incision, care should be taken to identify and retract the long saphenous vein and the accompanying saphenous nerve.
Retract the tendons of the tibialis posterior muscle anteriorly.
Retract the flexor digitorum longus muscle, flexor hallicus longus muscle, and the posterior tibial neurovascular bundle posteriorly.
Expose fracture site and free the periosteum from the fracture edges only as necessary to mobilize the fracture and visualize the reduction.