Ankle – Posterolateral Approach

Modern Study Review (AI-Generated)

High-Yield Summary

The posterolateral approach to the ankle is the gold standard for open reduction and internal fixation (ORIF) of posterior malleolar fractures and for addressing posterior ankle pathology. It provides excellent visualization of the posterior distal tibia and ankle joint while preserving critical neurovascular structures by exploiting the internervous plane between the superficial peroneal and tibial nerves. This extensile approach remains widely used in modern orthopaedics, although minimally invasive and arthroscopic techniques are increasingly used as adjuncts or alternatives in select cases.

Applied Anatomy & Intervals

Internervous Interval

• Between Peroneus Brevis (PB) muscle (innervated by the Superficial Peroneal Nerve) and Flexor Hallucis Longus (FHL) muscle (innervated by the Tibial Nerve).

Anatomic Landmarks

• Lateral malleolus
• Achilles tendon
• Posterior border of the fibula
• Posterior distal tibia

Patient Positioning & Setup

• Table Type: Standard operating table capable of prone positioning.
• Patient Position: Prone with the foot extending beyond the table edge to allow ankle manipulation.
• Specialized Equipment:
• Pneumatic tourniquet on thigh or calf for bloodless field.
• Limb positioner or sandbags to stabilize the leg.
• C-arm fluoroscopy positioned laterally or posteriorly for intraoperative imaging.

Surgical Technique (The “Vital Steps”)

Incision & Superficial Dissection

• Longitudinal incision midway between the lateral malleolus and Achilles tendon, extending proximally as needed.
• Mobilize skin flaps carefully to preserve the short saphenous vein and sural nerve, which run just posterior to the lateral malleolus.
• Incise the deep fascia in line with the skin incision.

Deep Dissection & Exposure

• Identify and isolate the peroneal tendons: Peroneus Brevis (PB) lies anterior to Peroneus Longus (PL) at the ankle level.
• PB is muscular proximally and tendinous distally.
• Incise the peroneal retinaculum to release and retract the tendons laterally.
• Identify the FHL tendon medially; incise the lateral fibers of FHL origin from the fibula to mobilize and retract it medially.
• Incise the periosteum of the distal tibia posteriorly and follow the posterior tibial surface down to the posterior ankle capsule.
• Incise the capsule transversely to expose the posterior ankle joint.

The “Danger Zone”

Post-Operative Pearl

Early mobilization is encouraged; however, avoid forced plantarflexion or inversion stresses for 4-6 weeks to protect the repaired posterior capsule and tendons.

Classic Clinical Notes

Ankle – posterolateral approach

• Position: Prone with tourniquet
• Incision: Long incision midway between lateral malleolus & Achilles tendon
• Internervous plane: Peroneus Brevis (PB) (Superficial Peroneal Nerve) & Flexor Hallucis Longus (FHL) (Tibial nerve)
• Dissection:
• Mobilize skin flaps
• Short saphenous vein & sural nerve run just behind lateral malleolus
• Incise deep fascia of leg in line with incision
• Identify 2 peroneal tendons
• PB anterior to PL at level of ankle
• PB muscular down to level of ankle
• Incise peroneal retinaculum to release tendons & retract laterally
• Expose FHL
• Incise lateral fibers of FHL as they arise from fibula
• Retract FHL medially
• Incise periosteum of distal tibia
• Follow posterior aspect of tibia down to posterior ankle & incise capsule transversely
• Dangers:
• Short saphenous vein & sural nerve

Last Updated on January 25, 2026 by orthonet