Posterolateral Approach to the Ankle

Posterolateral Approach to the Ankle ‌

The posterolateral approach is used to treat conditions of the posterior aspect of the distal tibia and ankle joint. It is well suited for open reduction and internal fixation of posterior malleolar fractures. Because the patient is prone, however, it is not the approach of choice if the fibula and medial malleolus have to be fixed at the same time. In such cases, it is better to use either a posteromedial approach or a lateral approach to the fibula, and to approach the posterolateral corner of the tibia through the site of the fractured fibula. Neither of these approaches provides such good

visualization of the bone as does the posterolateral approach to the ankle, but both allow other surgical procedures to be carried out without changing the position of the patient on the table halfway through the operation. Its other uses include the following:

1. Excision of sequestra

2. Removal of benign tumors

3. Arthrodesis of the posterior facet of the subtalar joint

4. Posterior capsulotomy and syndesmotomy of the ankle

5. Elongation of tendons

 

Position of the Patient

 

Place the patient prone on the operating table. As always, when the prone position is being used, longitudinal pads should be placed under the pelvis and chest so that the center portion of the chest and abdomen are free to move with respiration. A sandbag should be placed under the ankle so that it can be extended during the operation. Next, exsanguinate the limb by elevating it for 3 to 5 minutes or applying a soft rubber bandage; then inflate a tourniquet (Fig. 12-24).

 

Landmarks and Incision

Landmarks

The lateral malleolus is the subcutaneous distal end of the fibula. The Achilles tendon is easily palpable as it approaches its insertion into the calcaneus.

Incision

Make a 10-cm longitudinal incision halfway between the posterior border of the lateral malleolus and the lateral border of the Achilles tendon. Begin the incision at the level of the tip of the fibula and extend it proximally (Fig. 12-25).

 

Internervous Plane

 

The internervous plane lies between the peroneus brevis muscle (which is supplied by the superficial peroneal nerve) and the flexor hallucis longus muscle (which is supplied by the tibial nerve; Fig. 12-26).

 

 

Figure 12-24 Position of the patient for the posterolateral approach to the ankle joint.

 

Superficial Surgical Dissection

 

Mobilize the skin flaps. The short saphenous vein and sural nerves run just behind the lateral malleolus; they should be well anterior to the incision. Incise the deep fascia of the leg in line with the skin incision, and identify the two peroneal tendons as they pass down the leg and around the back of the lateral malleolus (Fig. 12-27). The tendon of the peroneus brevis muscle is anterior to that of the peroneus longus muscle at the level of the ankle joint and, therefore, is closer to the lateral malleolus. Note that the peroneus brevis is muscular almost down to the ankle, whereas the peroneus longus is tendinous in the distal third of the leg (see Figs. 12-64 and 12-65).

Incise the peroneal retinaculum to release the tendons, and retract the muscles laterally and anteriorly to expose the flexor hallucis longus muscle (Fig. 12-28). The flexor hallucis longus is the most lateral of the deep

flexor muscles of the calf. It is the only one that is still muscular at this level (see Fig. 12-65).

 

Deep Surgical Dissection

 

To enhance the exposure, make a longitudinal incision through the lateral fibers of the flexor hallucis longus muscle as they arise from the fibula (Fig. 12-29). Retract the flexor hallucis longus medially to reveal the periosteum over the posterior aspect of the tibia (Fig. 12-30). If the distal tibia must be reached, develop an epiperiosteal plane between the periosteum covering the tibia and the overlying soft tissues. To enter the ankle joint, follow the posterior aspect of the tibia down to the posterior ankle joint capsule and incise it transversely.

 

 

 

Figure 12-25 Make a 10-cm longitudinal incision halfway between the posterior

border of the lateral malleolus and the lateral border of the Achilles tendon.

 

 

 

Figure 12-26 The internervous plane lies between the peroneus brevis (which is supplied by the superficial peroneal nerve) and the flexor hallucis longus (which is supplied by the tibial nerve).

 

 

Figure 12-27 Mobilize the skin flaps. Incise the deep fascia of the leg in line with the skin incision. Identify the two peroneal tendons as they pass around the ankle.

 

 

Dang

 

 

The short saphenous vein and the sural nerve run close together. They should be preserved as a unit, largely to prevent the formation of a painful neuroma (see Fig. 12-64).

 

How to Enlarge the Approach

Extensile Measures

To enlarge the approach proximally, extend the skin incision superiorly and identify the plane between the lateral head of the gastrocnemius muscle and the peroneus muscles. Develop this plane down to the soleus

muscle; retract it medially with the gastrocnemius. Next, reflect the flexor hallucis longus muscle medially, detaching it from its origin on the fibula. Continue the dissection medially across the interosseous membrane to the posterior aspect of the tibia.

 

 

 

Figure 12-28 Incise the peroneal retinaculum to release the tendons. Retract them laterally and anteriorly. Incise the fascia over the flexor hallucis longus to expose its muscle fibers.

 

 

Figure 12-29 Make a longitudinal incision through the lateral fibers of the flexor hallucis longus as they arise from the fibula.

 

 

Figure 12-30 Retract the flexor hallucis longus medially to reveal the periosteum covering the posterior aspect of the tibia.