Posterolateral approach to the tibia

Introduction

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 heavily scarred or infected.

Indications

This approach can serve several purposes, including:

• Open reduction and internal fixation of tibial fractures
• Bone grafting for nonunion or delayed healing
• Implantation of electrical stimulators
• Excision or biopsy of bone lesions
• Osteotomy
• Fibular resection for fibular transfer

Patient Positioning

Place the patient on their side so the affected leg faces upward. Protect the bony prominences of the lower leg to prevent pressure sores.

Landmarks and Incision

Landmarks

• Gastrocnemius muscle

Incision

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

Internervous Plane

The internervous plane for the posterolateral approach to the tibia lies between:

Tibial nerve (posterior compartment)

Innervates:

• Gastrocnemius muscle
• Soleus muscle
• Flexor hallucis longus muscle

Superficial peroneal nerve (lateral compartment)

Innervates:

• Peroneus brevis muscle
• Peroneus longus muscle

Superficial Dissection

• Reflect the skin flaps, taking care not to damage the small saphenous vein, which runs from behind the lateral malleolus upward along the posterolateral side of the leg
• Incise the fascia in line with the skin incision and identify 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 muscle in the proximal part of the incision and may need to be ligated
• Identify the lateral border of the soleus and retract it with the gastrocnemius medially and posteriorly. Beneath this, originating from the posterior aspect of the fibula, lies the flexor hallucis longus

Deep Dissection

• Detach the lower portion of the soleus origin from the fibula and retract it posteriorly and medially
• Detach the flexor hallucis longus from its origin on the fibula and retract it posteriorly and medially
• Continue dissection medially across the interosseous membrane and detach the fibers of the tibialis posterior muscle that arise from it. The posterior tibial artery and tibial nerve lie behind 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, detach the muscles originating subperiosteally from its posterior surface, and expose the posterior surface of the tibia

Approach Extension

Proximal Extension

The posterolateral tibial approach cannot be extended into the proximal quarter of the tibia because the popliteus muscle, posterior tibial artery, and tibial nerve prevent proximal dissection.

Distal Extension

The posterolateral approach to the tibia can be extended distally to connect with the posterior approach to the ankle.

Dangers

Structures at risk during the posterolateral approach to the tibia include:

1. Small saphenous vein: May be damaged during mobilization of skin flaps. While the vein should be preserved when possible, it can be ligated if necessary without compromising 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. Posterior tibial artery and tibial nerve: Remain safe as long as the dissection plane stays on the interosseous membrane and does not wander into a plane behind the flexor hallucis longus and tibialis posterior muscles.

References

• Surgical Exposures in Orthopaedics – 4th Edition
• Campbell’s Operative Orthopaedics – 12th Edition