Posterolateral Approach to the Tibia

The posterolateral approach to the Tibia is used to expose the middle two thirds of the tibia when the skin over the subcutaneous surface is badly scarred or infected.

The Posterolateral Approach to the Tibia uses include the following:

1. Open reduction and internal fixation of tibia fractures.
2. Bone grafting for nonunion or delayed union.
3. Implantation of electrical stimulators.
4. Excision or biopsy of bone lesions.
5. Osteotomy.
6. Fibula resection for fibula transfer.

Position of the Patient

Place the patient on his or her side, with the affected leg uppermost. Protect the bony prominences of the bottom leg to avoid the development of pressure sores.

Landmarks and Incision

Landmarks:

• Gastrocnemius muscle.

Incision:

• Make a longitudinal incision over the lateral border of the gastrocnemius muscle.
• The length of the incision depends on the length of bone that must be exposed.

Internervous plane

The Internervous plan for the Posterolateral Approach to the Tibia lies between:

Tibial nerve (posterior compartment) which innervates:

• Gastrocnemius muscle.
• Soleus muscle.
• Flexor hallux longus muscle.

Superficial peroneal nerve (lateral compartment) which innervates:

• Peroneus brevis muscle
• Peroneus longus muscle.

Superficial dissection

• Reflect the skin flaps, taking care not to damage the short saphenous vein, which runs up the posterolateral aspect of the leg from behind the lateral malleolus.
• Incise the fascia in line with the incision and find the plane between the lateral head of the gastrocnemius and soleus muscles posteriorly, and the peroneus brevis and longus muscles anteriorly.
• Muscular branches of the peroneal artery lie with the peroneus brevis in the proximal part of the incision and may have to be ligated..
• Find the lateral border of the soleus and retract it with the gastrocnemius medially and posteriorly; underneath, arising from the posterior surface of the fibula, is the flexor hallucis longus.

Deep dissection

• Detach the lower part of the origin of the soleus muscle from the fibula and retract it posteriorly and medially.
• Detach the flexor hallucis longus muscle from its origin on the fibula and retract it posteriorly and medially.
• Continue dissecting medially across the interosseous membrane, detaching those fibers of the tibialis posterior muscle that arise from it. The posterior tibial artery and tibial nerve are posterior to the dissection, separated from it by the bulk of the tibialis posterior and flexor hallucis longus muscles.
• Follow the interosseous membrane to the lateral border of the tibia, detaching the muscles that arise from its posterior surface subperiosteally, and expose its posterior surface.

Approach Extension

Proximal Extension:

The Tibia Posterolateral Approach cannot be extended into the proximal fourth of the tibia, because popliteus muscle, posterior tibial artery, and tibial nerve prevent proximal dissection.

Distal Extension:

The Posterolateral Approach to the Tibia may be extended distally to become continuous with the posterior approach to the ankle.

Dangers

The structures at risk during the Posterolateral Approach to the Tibia include:

1. Short saphenous vein: it may be damaged when the skin flaps are mobilized. Although the vein should be preserved if possible, it may be ligated, if necessary, without impairing venous return from the leg.
2. Branches of the peroneal artery cross the intermuscular plane between the gastrocnemius and peroneus brevis muscles. They should be ligated or coagulated to reduce postoperative bleeding.
3. The posterior tibial artery and tibial nerve are safe as long as the surgical plane of operation remains on the interosseous membrane and does not wander into a plane posterior to the flexor hallucis longus and tibialis posterior muscles.

References

• Surgical Exposures in Orthopaedics book – 4th Edition.
• Campbel’s Operative Orthopaedics book 12th.