Posterolateral

Indications

• Posterior malleolar fractures needing direct reduction and buttress fixation.
• Fibular fractures that suit posterior antiglide plating, through the same incision.
• Posterolateral pilon fragments.

Position

• Prone, with a bump under the ankle. A lateral position can be used if a medial approach is also needed.
• Thigh tourniquet.

Landmarks and incision

• Palpate the lateral border of the Achilles tendon and the posterior border of the fibula.
• Make a 10 cm longitudinal incision midway between these two structures, ending at the level of the tip of the fibula.

Internervous plane

• The plane lies between peroneus longus and brevis (superficial peroneal nerve) and flexor hallucis longus (FHL, tibial nerve).

Superficial dissection

• Find the sural nerve and small saphenous vein in the subcutaneous tissue. They run close to the incision and cross the lateral border of the Achilles proximally.
• Protect the nerve throughout, as it is the structure most often injured.
• Incise the deep fascia in line with the skin.

Deep dissection

• Identify the peroneal tendons laterally and the low-lying FHL muscle belly medially.
• Develop the interval and retract FHL medially. This protects the posterior tibial neurovascular bundle.
• Elevate FHL from the posterior tibia to expose the posterior malleolus and posterior tibia.
• Retract the peroneals laterally or medially to expose the posterior fibula.
• Reduce the posterior fragment directly and fix with a buttress plate or posterior to anterior screws.

Structures at risk

• Sural nerve and small saphenous vein.
• Peroneal artery and its perforating branch, deep to FHL near the interosseous membrane.
• Posterior tibial artery and tibial nerve, if retraction of FHL is excessive or dissection strays medially.
• Skin, which is thin over the Achilles tendon.

Extensions

• Proximally along the posterolateral tibia for longer fractures.
• A separate posteromedial approach gives access to medial posterior malleolar fragments.

Exam traps

• Name the internervous plane and the nerve at risk.
• FHL muscle fibres extend lower than those of the other deep flexors, which helps orientation.
• Direct fixation of the posterior malleolus can restore syndesmotic stability through the posterior inferior tibiofibular ligament.
• Medial fragments are hard to reach from this approach. Assess them on CT first. See the ankle approaches.

References

1. Tornetta P, Ricci W, Nork S, Collinge C, Steen B. The posterolateral approach to the tibia for displaced posterior malleolar injuries. J Orthop Trauma. 2011, 25(2), 123-6.

2. Hoppenfeld S, deBoer P, Buckley R. Surgical exposures in orthopaedics, the anatomic approach. 5th ed. Philadelphia, Wolters Kluwer, 2017.

Reviewed by Professor Phong Tran, Head of Orthopaedic Surgery, Western Health. Last updated 17 October 2026.