Posteromedial Approach to the Proximal Tibia

Posteromedial Approach to the Proximal Tibia

 

 

Complex fractures of the tibial plateau often involve a large posteromedial fragment. Accurate reduction of this fragment onto the tibial shaft is critical to allow reconstruction of the joint and is often the first stage in surgery of bicondylar tibial plateau fractures. Plates applied to the

posteromedial aspect of the tibia prevent varus deformity, the most common deformity of the proximal tibia after fracture. Biomechanically, these plates are on the compression side of the bone and function as buttress plates. Another potential advantage of the approach is that the skin and soft tissues on the posteromedial aspect of the tibia are usually free from blisters that commonly occur on the anterior portion of the tibia following trauma. However, if the soft tissues on the posteromedial aspect of the proximal tibia are poor, surgery must be delayed until the soft tissue conditions have improved.

The indications for this approach include:

1. Open reduction and internal fixation of fractures of the medial tibial plateau (Schatzker Type 4)

2. Open reduction and internal fixation of complex bicondylar tibial plateau fractures (Schatzker Types 5 and 6)

3. Upper tibial osteotomy

4. Drainage of abscess

5. Biopsy of tumors

 

Position of the Patient

 

Place the patient supine on a radiolucent table and ensure that adequate visualization of the fracture can be obtained using an image intensifier. Position a sandbag beneath the contralateral hip to roll the patient approximately 20 degrees (Fig. 11-6). This will increase the external rotation of the affected limb, bringing the posteromedial corner of the tibia forward. Ease of access is also improved if the surgeon stands on the opposite side of the table from the approach. Exsanguinate the limb by elevating it for 3 to 5 minutes or by applying a soft rubber bandage. Inflate a tourniquet.

 

 

Figure 11-6 Place the patient supine on a radiolucent table. Position a sandbag beneath the contralateral hip to roll the patient approximately 20 degrees.

 

Landmarks and Incision

Landmarks

The upper end of the tibia is triangular and the posteromedial surface where the tibia flares is easily palpated, even in very obese individuals.

Incisions

Make a 6-cm longitudinal incision overlying the posteromedial border of the proximal tibia. The exact length of the incision will depend on the pathology to be treated and the implant to be used (Fig. 11-7).

 

Internervous Plane

There is no internervous plane in this approach. The plane between the bone and the gastrocnemius muscle is utilized.

 

Superficial Surgical Dissection

 

Deepen the incision through the subcutaneous fat. The long saphenous vein and the saphenous nerve will be just anterior to the surgical approach; these structures should be identified and preserved. Identify the pes anserinus expansion overlying the tibia (Fig. 11-8A).

The tibia can be approached using two different techniques.

Direct approach—Divide the pes anserinus longitudinally in the line of the skin incision. This technique has the advantage of simplicity but repair of the pes is difficult during closure especially since a plate will almost always have been applied to the bone.

Pes reflecting approach—Identify the anterior border of the pes which is the anterior border of the sartorius tendon. Reflect the sartorius tendon posteriorly entering the bursa underneath the tendon. Identify the tendons of gracilis and semitendinosus and reflect all three tendons posteriorly partially resecting them from their insertion into the tibia (Fig. 11-8B).

 

Deep Surgical Dissection

 

The posteromedial border of the tibia is now revealed. To facilitate plate placement develop an epiperiosteal plane between the pes anserinus and the medial head of the gastrocnemius at the posteromedial border of the tibia. The muscle can be gently freed from the bone by blunt dissection (Fig. 11-9).

 

 

Figure 11-7 Make a 6-cm longitudinal incision overlying the posteromedial border of the proximal tibia. The exact length of the incision will depend on the pathology to be treated and the implant to be used.

 

 

Dang

 

 

Vessels

The saphenous nerve and vein are encountered during the superficial

surgical dissection and should be preserved and protected.

 

How to Enlarge the Approach

Proximal Extension

To reach the posteromedial corner of the knee, the incision may be extended proximally around the medial border of the tibia. Access to the popliteal artery and vein for vascular surgery is also possible through this extension.

Distal Extension

To extend the approach distally, continue down along the medial side of the posteromedial tibia. Not only will this give you access to the posteromedial border of the tibia, but it also provides access to both the superficial and deep posterior compartments of the leg for compartment release.

 

 

 

Figure 11-8 A: Deepen the incision through the subcutaneous fat. The long saphenous vein and the saphenous nerve will be just anterior to the surgical approach; these structures should be identified and preserved. Identify the pes anserinus expansion overlying the tibia. B: To approach the tibia, either divide the

pes anserinus longitudinally in the line of the skin incision or identify the anterior border of the pes and partially resect it from its insertion into the tibia, reflecting it posteriorly.

 

 

 

Figure 11-9 Develop an epiperiosteal plane between the pes anserinus and the medial head of the gastrocnemius at the posteromedial border of the tibia. The muscle can be gently freed from the bone by blunt dissection.