Courtesy: Amr Abdelgawad, Maimonaides Medical Centre, NY, USA

Posterolateral Approach to the Ankle

• Commonly used for ORIF of posterior malleolus fractures.
• Interval: between peroneal tendons (lateral) and flexor hallucis longus (medial).
• Flexor hallucis longus muscle extends distally close to the ankle (“beef to heel” characteristic).
• Structure at risk: Sural nerve.
• Small saphenous vein lies medial to the sural nerve.
• To protect the nerve, retract the vein laterally.

Lateral Approach to the Fibula

• Used for fixation of lateral malleolus fractures.
• Structure at risk: Superficial peroneal nerve.
• Nerve becomes superficial approximately 12 cm proximal to the tip of the distal fibula.
• Care is required during dissection around this level.

Anterior Approach to the Ankle

• Structure most at risk: Medial dorsal cutaneous branch of the superficial peroneal nerve.
• Important during open ankle surgery.
• Nerve injury may cause dorsal foot sensory deficits.

Talus Fracture Surgical Considerations

• Double incision approaches risk disruption of talar blood supply.
• Deltoid branch of the artery of the tarsal canal may remain the only blood supply.
• Preservation of deltoid branches is critical to avoid avascular necrosis.

Master Knot of Henry

• Crossing point of flexor hallucis longus (FHL) and flexor digitorum longus (FDL).
• Occurs near the level of the subtalar joint.
• FHL passes deep to FDL.
• Important surgical landmark in medial foot approaches.

Extensile Lateral Approach for Calcaneus

• Used for calcaneal fracture fixation.
• Provides excellent exposure of the calcaneus.
• Requires elevation of a lateral skin flap.
• Main blood supply of the flap: Lateral calcaneal artery.
• Artery located approximately 1.5 cm anterior to Achilles tendon.
• Vertical incision placed about 0.5 cm from Achilles tendon to avoid vascular injury.

Ankle Arthroscopy Portals

• Anteromedial portal: medial to tibialis anterior tendon.
• Structures at risk: saphenous nerve and saphenous vein.
• Anterolateral portal: lateral to peroneus tertius tendon.
• Structures at risk: superficial peroneal nerve or intermediate dorsal cutaneous branch.
• Posterolateral portal: lateral to Achilles tendon.
• Structures at risk: sural nerve and small saphenous vein.
• Most commonly injured nerve during ankle arthroscopy: intermediate dorsal cutaneous branch.

Anterior Tibial Artery and Deep Peroneal Nerve Relationship

• In the lower leg: anterior tibial artery lies medial to the deep peroneal nerve.
• At ankle level the artery passes beneath extensor retinaculum.
• Foot relationship (medial ? lateral): tibialis anterior ? extensor hallucis longus ? artery & nerve ? extensor digitorum longus.

Intrinsic Muscles of the Foot

• Function similar to intrinsic muscles of the hand.
• Flex metatarsophalangeal joints.
• Extend interphalangeal joints.
• Weakness results in claw toe deformity: MTP extension with IP flexion.

Compartments of the Foot

• Total of nine compartments.
• Four interosseous compartments.
• Medial compartment.
• Lateral compartment.
• Two central compartments (superficial and deep/adductor).
• Calcaneal compartment.
• There is no dorsal compartment.

Syndesmosis Ligaments

• Interosseous ligament between tibia and fibula.
• Anterior inferior tibiofibular ligament (AITFL).
• Posterior inferior tibiofibular ligament (PITFL).
• AITFL avulsion fracture produces Tillaux fracture.

Flexor Hallucis Longus Anatomy

• Runs lateral to the posteromedial tubercle of the talus.
• Passes in a groove behind the talus.
• Turns under the sustentaculum tali.
• Long calcaneal screws may irritate the FHL tendon.
• Crosses flexor digitorum longus at the Master Knot of Henry.

Peroneal Tendons

• Peroneus brevis lies deeper and closer to the fibula.
• Mnemonic: “Brevis is by the Bone”.
• Peroneus longus lies more superficial.
• Peroneal tubercle separates the tendons at the calcaneus.
• Peroneus brevis passes superior/anterior to the tubercle.
• Peroneus longus passes inferior/plantar to the tubercle.

Functions of Peroneal Muscles

• Peroneus brevis: foot eversion.
• Peroneus longus: eversion and plantarflexion of the first ray.
• Peroneus longus contributes to maintenance of the longitudinal arch.

Muscle Antagonists in Foot Mechanics

• Posterior tibial muscle (inversion) vs peroneus brevis (eversion).
• Tibialis anterior (inversion and dorsiflexion) vs peroneus longus (eversion and plantarflexion of first ray).
• Important in cavus foot pathology.

Lisfranc Ligament

• Connects medial cuneiform to base of second metatarsal.
• Key stabilizer of the tarsometatarsal joint.
• Injury results in Lisfranc fracture-dislocation.

Spring Ligament (Plantar Calcaneonavicular Ligament)

• Runs from calcaneus to navicular.
• Supports the talar head and talonavicular joint.
• Prevents collapse of the medial arch.
• Injury associated with posterior tibial tendon dysfunction.
• Important in adult acquired flatfoot deformity.

Lateral Ankle Ligaments

• Anterior talofibular ligament (ATFL) most commonly injured.
• ATFL stressed during inversion and plantarflexion.
• Calcaneofibular ligament stressed during inversion and dorsiflexion.

Hallux Sesamoids

• Two sesamoids: medial (tibial) and lateral (fibular).
• Embedded in the tendons of flexor hallucis brevis.
• Flexor hallucis longus tendon runs between them.
• Excision of medial sesamoid may cause hallux valgus.
• Excision of lateral sesamoid may cause hallux varus.
• Removal of both sesamoids may produce cock?up deformity.
• Plantar plate attaches to the base of the proximal phalanx.

Blood Supply of the Talus

• Three main sources: artery of tarsal canal, artery of sinus tarsi, and deltoid branch.
• Tarsal canal artery from posterior tibial artery supplies most of talar body.
• Deltoid branch supplies medial talar body.
• Sinus tarsi artery from anastomosis of anterior tibial and perforating peroneal arteries.
• Sinus tarsi artery supplies talar head and neck.
• Deltoid branch may be the only remaining blood supply after talar fractures.