Anterior Approach to the Tibia
Anterior Approach to the Tibia
The anterior approach offers safe, easy access to the medial (subcutaneous) and lateral (extensor) surfaces of the tibia. It is used for the following:
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Open reduction and internal fixation of tibial fractures1
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Bone grafting for delayed union or nonunion of fractures2
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Excision of sequestra or saucerization in patients with osteomyelitis
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Excision and biopsy of tumors
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Osteotomy
Plates applied to the subcutaneous surface of the tibia are placed correctly biomechanically on the medial (tensile) side of the bone; they also are easier to contour there. Some surgeons prefer to use the lateral surface for plating, however, to avoid the problems of subcutaneous placement which may result in breakdown of the wound.
The anterior approach is the preferred approach to the tibia except when the skin is scarred or has draining sinuses in it.
Position of the Patient
Place the patient supine on the operating table. The use of a tourniquet is optional. Tourniquets should not be used if this approach is to be used in conjunction with the exploration of an open wound. If you wish to use a tourniquet, exsanguinate the limb by elevating it for 3 to 5 minutes, then inflate a tourniquet (Fig. 11-27).
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Figure 11-27 Position for the anterior approach to the tibia.
Landmarks and Incision
Landmarks
The shaft of the tibia is roughly triangular when viewed in cross section. It has three borders, one anterior, one medial, and one interosseous (posterolateral). These borders define three distinct surfaces: (1) a medial subcutaneous surface between the anterior and medial borders, (2) a lateral (extensor) surface between the anterior and interosseous borders, and (3) a posterior (flexor) surface between the medial and interosseous (posterolateral) borders. The anterior and medial borders and the subcutaneous surface are easily palpable.
Incision
Make a longitudinal incision on the anterior surface of the leg parallel to the anterior border of the tibia and about 1 cm lateral to it. The length of the incision depends on the requirements of the procedure. Because of the poor vascularity of the skin it is safer to make a longer incision than to retract skin edges forcibly to obtain access. The tibia can be exposed along its entire length (Fig. 11-28).
Internervous Plane
There is no internervous plane in this approach. The dissection is epiperiosteal and does not disturb the nerve supply to the extensor compartment.
Superficial Surgical Dissection
Elevate the skin flaps to expose the subcutaneous surface of the tibia. The long saphenous vein is on the medial side of the calf and must be protected when the medial skin flap is reflected (Fig. 11-29).
Deep Surgical Dissection
Two surfaces of the tibia can be approached through this incision.
Subcutaneous (Medial) Surface
The periosteum of the tibia provides a small but vital blood supply to the bone in fractures where the endosteal blood supply is damaged. For this reason, periosteal stripping must be kept to an absolute minimum. In particular, never strip the periosteum off an isolated fragment of bone, or the bone will become totally avascular.
Lateral (Extensor) Surface
Reflect the tibialis anterior muscle from the periosteum and retract it laterally to expose the lateral surface of the bone. The tibialis anterior is the only muscle to take origin from the lateral surface of the tibia; detaching the muscle completely exposes that surface (see Fig. 11-30)
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Figure 11-28 Make a longitudinal incision on the anterior surface of the leg.
Dang
Vessels
The long saphenous vein, which runs up the medial side of the calf, is vulnerable during superficial surgical dissection and should be preserved for future vascular procedures, if at all possible.
Special Surgical Points
Skin flaps must be closed meticulously after surgery to avoid infection of the tibia. Although longitudinal incisions over the tibia heal well, transverse incisions and irregular wounds may heal poorly, especially in elderly individuals. The skin over the lower third of the tibia is very thin; wounds in that area heal badly, especially in smokers or patients with chronic venous insufficiency.
It is important to minimize the amount of soft tissue that is stripped from bone in this approach when it is used for fracture work. Devascularized bone, no matter how well it is reduced and fixed, will not unite. Using care and appropriate reduction forceps, it usually is possible to preserve soft tissue attachments of all but the smallest fragments of bone.
How to Enlarge the Approach
Local Measures
The extent of the exposure is determined by the size of the skin incision; the whole subcutaneous surface of the tibia may be exposed, if necessary.
To reach the posterior surface of the tibia from an anterior approach, continue the epiperiosteal dissection posteriorly around the medial border. Proximally, lift the flexor digitorum longus muscle off the posterior surface of the tibia subperiosteally. Distally, lift off the tibialis posterior muscle. This procedure exposes the posterior surface of the bone, but does not offer as full an exposure as does the posterolateral approach. It also detaches many of the soft tissue attachments to the bone. It probably is useful only for the insertion of bone graft as part of an internal fixation carried out through this anterior route.
Extensile Measures
Proximal Extension. To extend the approach proximally, continue the skin incision along the medial side of the patella. Deepen the incision through the medial patellar retinaculum to gain access to the knee joint and the patella. (For details, see Medial Parapatellar Approach in Chapter 10, Fig. 10-10.) Alternatively, extend the wound proximally along the lateral side of the patella. Deepen that wound through the lateral patellar retinaculum to gain access to the lateral compartment of the knee.
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Figure 11-29 Elevate the skin flaps over the medial portion of the tibialis anterior and the subcutaneous medial surface of the tibia. To expose the lateral surface of the tibia, incise the deep fascia over the medial border of the tibialis anterior.
Distal Extension. To extend the approach distally, curve the incision over the medial side of the hind part of the foot. Deepening the wound provides access to all the structures that pass behind the medial malleolus. Continue the incision onto the middle and front parts of the foot. (For details, see Anterior and Posterior Approaches to the Medial Malleolus in Chapter 12, Fig. 12-6.)
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Figure 11-30 Elevate the tibialis anterior from the lateral surface of the tibia. Incise the periosteum; elevate it only as necessary.