Lateral Approach to the Lateral Malleolus
Lateral Approach to the Lateral Malleolus
The approach to the lateral malleolus is used primarily for open reduction and internal fixation of lateral malleolar fractures. It also offers access to the posterolateral aspect of the tibia.
Position of the Patient
Place the patient supine on the operating table with a sandbag under the buttock of the affected limb. The sandbag causes the limb to rotate medially, bringing the lateral malleolus forward and making it easier to
reach (Fig. 12-31). Tilt the table away from you to further increase the internal rotation of the limb. Operating with the patient on his or her side also provides excellent access to the distal fibula, but the medial malleolus cannot be reached unless the patient’s position is changed, something that is necessary in the fixation of bimalleolar fractures (Fig. 12-32). Exsanguinate the limb by elevating it for 3 to 5 minutes, then inflate a tourniquet.
Landmarks and Incision
Landmarks
Palpate the subcutaneous surface of the fibula and the lateral malleolus, which lies at its distal end. The short saphenous vein can be seen running along the posterior border of the lateral malleolus before the limb is exsanguinated.
Incision
Make a 10- to 15-cm longitudinal incision along the posterior margin of the fibula all the way to its distal end and continuing for a further 2 cm (Fig. 12-33A). In fracture surgery, center the incision at the level of the fracture.
Internervous Plane
There is no internervous plane, because the dissection is being performed down to a subcutaneous bone. For higher fractures of the fibula, the internervous plane lies between the peroneus tertius muscle (which is supplied by the deep peroneal nerve) and the peroneus brevis muscle (which is supplied by the superficial peroneal nerve).
Superficial Surgical Dissection
Elevate the skin flaps, taking care not to damage the short saphenous vein, which lies posterior to the lateral malleolus. The sural nerve, which runs with the short saphenous vein, also should be preserved.
Deep Surgical Dissection
Incise the periosteum of the subcutaneous surface of the fibula longitudinally, and strip off just enough of it at the fracture site to expose the fracture adequately. Take care to keep all dissection strictly
subperiosteal, because the terminal branches of the peroneal artery, which lie close to the lateral malleolus, may be damaged. Only strip off as much periosteum as is necessary for accurate reduction; periosteal stripping markedly reduces the blood supply of the bone in cases of fracture (Fig. 12-33B,C; see Fig. 12-64).
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Figure 12-31 Position of the patient for exposure of the lateral malleolus.
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Figure 12-32 An alternate position for exposure of the lateral malleolus. Place the patient prone or on his or her side, with a sandbag under the pelvis of the affected side.
Dang
Nerves
The sural nerve is vulnerable when the skin flaps are mobilized. Cutting it may lead to the formation of a painful neuroma and numbness along the lateral skin of the foot, which, although it does not bear weight, does come in contact with the shoe. The nerve also is valuable as a nerve graft. Preserve it if possible (see Fig. 12-61).
Vessels
The terminal branches of the peroneal artery lie immediately deep to the medial surface of the distal fibula. They can be damaged if dissection is extensive. The damage may not be noticed during surgery because of the tourniquet, but a hematoma may form after the tourniquet is taken off. That is why it is best to deflate the tourniquet before closure to ensure hemostasis; then, the wound can be drained with a suction drain (see Fig. 12-64).
How to Enlarge the Approach
Extensile Measures
Proximal Extension. Extend the incision along the posterior border of the fibula, incising the deep fascia in line with the skin incision. Develop a new plane between the peroneal muscles (which are supplied by the superficial peroneal nerve) and the flexor muscles (which are supplied by the tibial nerve). The upper third of the fibula can be exposed if the common peroneal nerve can be identified near the knee and traced down toward the ankle. (For details of this approach, see Approach to the Fibula in Chapter 11, page 617.)
Distal Extension. To extend the approach distally, curve the incision down the lateral side of the foot. Identify the peroneal tendons and incise the peroneal retinacula. Detach the fat pad in the sinus tarsi and the origin of the extensor digitorum brevis muscle to expose the calcaneocuboid joint on the lateral side of the tarsus (see Figs. 12-61 and 12-62).
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Figure 12-33 A: Make a 10- to 15-cm incision along the posterior margin of the fibula all the way to its distal end. From there, curve the incision forward, below the tip of the lateral malleolus. B: Incise the periosteum on the subcutaneous surface of the fibula longitudinally. C: Expose the distal fibula subperiosteally.