Anterior Approach to the Ankle

Anterior Approach to the Ankle ‌‌

The anterior approach provides excellent exposure of the ankle joint for arthrodesis.1 The decision to use this approach rather than the lateral transfibular approach, the medial transmalleolar approach, or the posterior approach depends on the condition of the skin and the surgical technique to be used. Its other uses include the following:

1. Drainage of infections in the ankle joint

2. Removal of loose bodies

3. Open reduction and internal fixation of comminuted distal tibial fractures (pilon fractures)

 

Position of the Patient

 

Place the patient supine on the operating table. Partially exsanguinate the foot either by elevating it for 3 to 5 minutes or by applying a soft rubber bandage loosely to the foot and binding it firmly to the calf. Then, inflate a thigh tourniquet. Partial exsanguination allows the neurovascular bundle to be identified, because the venous structures will appear blue. Some continuous vascular oozing must be expected, however (Fig. 12-1).

 

 

 

Figure 12-1 Position for the anterior approach to the ankle.

 

Landmarks and Incision

Landmarks

The medial malleolus is the bulbous, subcutaneous, distal end of the medial surface of the tibia. The lateral malleolus is the subcutaneous distal end of the fibula.

Incision

Make a 15-cm longitudinal incision over the anterior aspect of the ankle joint. Begin about 10 cm proximal to the joint, and extend the incision so that it crosses the joint about midway between the malleoli, ending on the dorsum of the foot. Take great care to cut only the skin; the anterior neurovascular bundle and branches of the superficial peroneal nerve cross the ankle joint very close to the line of the skin incision (Fig. 12-2A). Alternatively, make a 15-cm longitudinal incision with its center overlying the anterior aspect of the medial malleolus (see Fig. 12-2).

 

Internervous Plane

 

Although the approach uses no true internervous plane, the extensor hallucis longus and extensor digitorum longus muscles define a clear intermuscular plane. Both muscles are supplied by the deep peroneal nerve, but the plane may be used because both receive their nerve supplies well proximal to the level of the dissection. The plane must be used with great caution, however, because it contains the neurovascular bundle distal to the ankle (see Figs. 12-58 and 12-59).

 

Superficial Surgical Dissection

 

Incise the deep fascia of the leg in line with the skin incision, cutting through the extensor retinaculum (see Fig. 12-2B). Find the plane between the extensor hallucis longus and extensor digitorum longus muscles a few centimeters above the ankle joint, and identify the neurovascular bundle (the anterior tibial artery and the deep peroneal nerve) just medial to the tendon of the extensor hallucis longus (see Fig. 12-2C). Trace the bundle distally until it crosses the front of the ankle joint behind the tendon of the extensor hallucis longus. Retract the tendon of the extensor hallucis longus medially, together with the neurovascular bundle. Retract the tendon of the extensor digitorum longus laterally. The tendons become mobile after the

retinaculum has been cut, but the neurovascular bundle adheres to the underlying tissues and requires mobilization (Fig. 12-3A).

Alternatively, in pilon fractures, incise the deep fascia to the medial side of the tibialis anterior tendon (Fig. 12-4), and expose the underlying surface of the tibia together with the anteromedial ankle joint capsule.

 

Deep Surgical Dissection

 

For arthrodesis surgery, incise the remaining soft tissues longitudinally to expose the anterior surface of the distal tibia. Continue incising down to the ankle joint, then cut through its anterior capsule. Expose the full width of the ankle joint by detaching the anterior ankle capsule from the tibia or the talus by sharp dissection (see Fig. 12-3). Some periosteal stripping of the distal tibia may be required. Although the periosteal layer usually is thick and easy to define, the plane may be obliterated in cases of infection; the periosteum then must be detached piecemeal by sharp dissection.

 

 

 

Figure 12-2 A: Make a longitudinal incision over the anterior aspect of the ankle joint. B: Identify and protect the superficial peroneal nerve. Incise the extensor retinaculum in line with the skin incision. C: Identify the plane between the extensor hallucis longus and the extensor digitorum longus, and note the neurovascular bundle between them.

 

 

Figure 12-3 A: Retract the tendon of the extensor hallucis longus medially with the neurovascular bundle. Retract the tendon of the extensor digitorum longus laterally. Incise the joint capsule longitudinally. B: Retract the joint capsule to expose the ankle joint.

 

If the approach is used in fracture surgery, take great care to preserve as much soft tissue attachments to bone as possible. Meticulous preoperative planning will allow smaller, precise incisions with consequent reduction in soft tissue damage.

 

 

Dang

 

 

Nerves

Cutaneous branches of the superficial peroneal nerve run close to the line of the skin incision just under the skin. Take care not to cut them during incision of the skin (see Fig. 12-2A).

The deep peroneal nerve and anterior tibial artery (the anterior neurovascular bundle) must be identified and preserved during superficial surgical dissection. They are in greatest danger during the skin incision, because they are superficial and run close to the incision itself (see Figs. 12-58 and 12-59). Above the ankle joint, the neurovascular bundle lies

between the tendons of the extensor hallucis longus and tibialis anterior muscles at the joint; the tendon of the extensor hallucis longus crosses the bundle. The plane between the tibialis anterior and the extensor hallucis longus can be used as long as the neurovascular bundle is identified and mobilized so as to preserve it (see Fig. 12-59).

 

How to Enlarge the Approach

Extensile Measures

Although this approach does not descend through an internervous plane, on occasion it can be extended proximally to expose the structures in the anterior compartment. To expose the proximal tibia, use the plane between the tibia and the tibialis anterior muscle (see Fig. 12-4). Distal extension to the dorsum of the foot is possible, but rarely, if ever, required (see Fig. 12-59).

 

 

 

Figure 12-4 A: Alternately, incise the extensor retinaculum on the medial side of the tibialis anterior tendon. B: Retract the tibialis anterior laterally to expose the anterior surface of the ankle joint.