Medial Approach to the Talus and Navicular

Position: Supine with bump under ipsilateral hip

Pre-positioning Checklist:

• Confirm tourniquet availability (thigh or calf)
• Radiolucent table or foot extension
• C-arm access from contralateral side
• Ankle position: slight plantarflexion relaxes capsule
• Tourniquet applied high on thigh or below knee

Positioning Details:

• Supine position with bump under ipsilateral hip to internally rotate the foot
• Affected foot at end of table or with foot extension
• Knee slightly flexed (20-30 degrees) for relaxation
• Tourniquet optional but recommended for clear field
• Prepare entire leg to knee for potential extension

Alternative Positioning:

• Lateral decubitus if combined lateral approach planned
• Allows access to both medial and lateral talus without repositioning
• Some surgeons prefer for complex talar neck fractures

Key Bony Landmarks:

• Medial malleolus - palpable prominence, starting point of incision
• Navicular tuberosity - palpable prominence on medial midfoot
• Talar neck - can be palpated anterior to malleolus with foot plantarflexed
• First metatarsal base - distal landmark if extended
• Medial cuneiform - palpable distal to navicular

Key Soft Tissue Landmarks:

• Saphenous vein - visible or palpable anterior to medial malleolus
• Saphenous nerve - runs with vein, 1-2cm anterior to planned incision
• Tibialis posterior tendon - posterior to medial malleolus, behind incision
• Tibialis anterior tendon - anterior border of incision
• Deltoid ligament - deep to incision, attaches to talus and navicular

Incision Planning:

• Longitudinal incision starting 2cm proximal to medial malleolus tip
• Extends distally to navicular tuberosity (approximately 8-10cm)
• Placed midway between tibialis anterior and posterior tendons
• Slightly anterior to the medial malleolus tip
• Can be extended proximally along medial tibia or distally to first metatarsal

Deep Internervous Plane:

• Between: Tibialis anterior (deep peroneal nerve) anteriorly and tibialis posterior (tibial nerve) posteriorly
• Clinical relevance: This is the safe interval between muscles innervated by different nerves (deep peroneal vs tibial)
• The plane is relatively bloodless and allows direct access to the medial talar neck and talonavicular joint

Superficial Dissection: There is no true internervous plane superficially. The saphenous nerve (sensory branch of femoral nerve) is the key structure and must be protected. The incision is placed posterior to the saphenous nerve and vein.

Structures at Risk in Each Layer:

Danger Structures by Layer:

Superficial Layer:

• Saphenous vein: Identify and retract anteriorly. Ligate small branches if needed but preserve main vein.
• Saphenous nerve: Runs with the vein. Injury causes medial foot numbness and neuroma pain. Protect with gentle retraction.

Intermediate Layer:

• Deltoid ligament (superficial and deep components): The deep deltoid is critical for ankle stability and talar vascularity. Detach only what is necessary and repair at closure.
• Tibialis posterior tendon: Lies posterior to the malleolus. Retract posteriorly if exposure requires.

Deep Layer:

• Artery of the tarsal canal: Branch of posterior tibial artery. Enters the tarsal canal and supplies the majority of the talar body. Avoid stripping or ligating this vessel. The deltoid branch enters via the deltoid ligament.
• Medial plantar nerve: Distal extension may encounter branches. Protect during navicular exposure.

Articular Layer:

• Talar dome cartilage: Protect during osteotomy and retraction. Use blunt instruments.
• Talonavicular joint capsule: Incise longitudinally, preserve for repair.

Extension Risks:

• Proximal extension risks saphenous nerve and great saphenous vein.
• Distal extension risks medial plantar nerve and tibialis posterior insertion.

Proximal Extension:

• Extend the incision proximally along the medial border of the tibia.
• Develop the interval between tibialis anterior and the medial border of tibia.
• Allows access to the medial tibial plafond and distal tibial metaphysis.
• Useful for combined ankle and talar pathology or medial malleolar fractures.

Distal Extension:

• Extend distally along the medial border of the foot toward the first metatarsal base.
• Exposes the medial cuneiform and first tarsometatarsal joint.
• Useful for extended talonavicular fusion or midfoot reconstruction.
• Protect the tibialis anterior insertion and medial plantar nerve branches.

Combined Approaches:

• Lateral approach to the talus (Ollier or Kocher) for complete talar neck exposure.
• Anterolateral approach for lateral talar neck comminution.
• Posterior approach (posteromedial) for talar body fractures requiring posterior access.
• Often combined with lateral approach for talar neck fractures with medial comminution.

Medial Malleolar Osteotomy Extension:

• When performed, the osteotomy allows the medial malleolus to be reflected inferiorly on the deltoid ligament hinge.
• Provides access to the entire medial talar dome and medial half of the talar body.
• Must be fixed anatomically with two parallel screws (3.5mm or 4.0mm) directed perpendicular to the osteotomy.

Step 1: Incision and Superficial Dissection

Make a longitudinal incision starting 2cm proximal to the tip of the medial malleolus and extending distally to the navicular tuberosity (total length 8-10cm). The incision is placed midway between the tibialis anterior tendon (anterior) and the tibialis posterior tendon (posterior), slightly anterior to the medial malleolus tip.

Incise skin and subcutaneous tissue. Identify the saphenous vein and nerve, which lie anterior to the incision. Gently retract the neurovascular bundle anteriorly and protect with a vessel loop or Penrose drain if necessary. Avoid excessive retraction or ligation of the main vein.

Incise the deep fascia in line with the skin incision. The interval between tibialis anterior (anterior) and tibialis posterior (posterior) is developed. This is the deep internervous plane.

Step 2: Deep Dissection and Exposure

Deepen the interval between tibialis anterior and tibialis posterior. The tibialis posterior tendon is retracted posteriorly. The deltoid ligament is encountered deep to the interval. The ligament is preserved or partially detached only as necessary for exposure.

The capsule of the talonavicular joint and the medial ankle joint is incised longitudinally. The talar neck and body are exposed. The navicular is exposed distally. The artery of the tarsal canal is protected by avoiding aggressive dissection in the region of the tarsal canal (inferior to the talar neck).

For exposure of the medial talar dome, a medial malleolar osteotomy is performed. The osteotomy starts at the tip of the medial malleolus and is directed obliquely proximally into the tibial plafond. The osteotomy is extra-articular and the deltoid ligament remains attached to the malleolar fragment. The malleolus is reflected inferiorly on the deltoid hinge, exposing the medial talar dome.

Danger Structures Named Per Layer:

Skin and Subcutaneous:

• Saphenous vein and nerve (anterior to incision)

Fascial Layer:

• No major structures, but protect saphenous during fascial incision

Muscular/Interval Layer:

• Tibialis anterior tendon (anterior retraction)
• Tibialis posterior tendon (posterior retraction)
• Deltoid ligament (preserve attachment)

Deep Vascular Layer:

• Artery of the tarsal canal (critical - enters tarsal canal, supplies talar body)
• Deltoid branch of artery of tarsal canal (enters via deltoid ligament)
• Posterior tibial artery (more posterior, usually protected)

Articular Layer:

• Talar dome and neck cartilage
• Talonavicular joint articular surface
• Navicular articular surface

Tendon Layer (if extended):

• Tibialis posterior insertion on navicular
• Medial plantar nerve branches (distal)

Procedures Performed Through This Approach:

Talar Neck Fractures (Hawkins Types I-IV):

• Direct visualization and reduction of medial neck comminution
• Medial buttress plating or lag screw fixation
• Often combined with lateral approach for complete exposure
• Bone grafting of comminuted areas

Medial Talar Dome OCD Lesions:

• Medial malleolar osteotomy provides access to medial dome
• Microfracture, OATS, or fixation of osteochondral fragment
• Debridement and drilling under direct vision

Talonavicular Arthrodesis:

• Exposure of talonavicular joint
• Cartilage denudation, bone grafting, and screw or plate fixation
• Part of triple arthrodesis or isolated TN fusion

Navicular Fractures:

• Exposure of navicular body and tuberosity fractures
• ORIF with screws or plate
• Protection of tibialis posterior insertion

Talar Body Fractures (Medial Column):

• Access to medial talar body
• Reduction and fixation of medial body fragments
• Combined with other approaches for complex patterns

Talar Head and Neck Pathology:

• Access for tumor resection, osteochondroma excision
• Bone grafting of cystic lesions

Closure and Osteotomy Fixation:

Layered Closure:

• Deep capsule and ligament repair: 2-0 or 3-0 absorbable sutures
• Deltoid ligament repair if partially detached: 2-0 non-absorbable or absorbable
• Fascia: 2-0 absorbable
• Subcutaneous tissue: 3-0 absorbable
• Skin: 3-0 or 4-0 nylon or absorbable subcuticular

Medial Malleolar Osteotomy Fixation:

• Two parallel 3.5mm or 4.0mm partially threaded cancellous screws
• Screws directed perpendicular to the osteotomy plane
• Length measured to engage the far cortex of the tibia
• Washers used if osteoporotic bone
• Anatomic reduction confirmed fluoroscopically
• No step-off or gap at the osteotomy site

Post-operative Protocol:

• Posterior splint or boot with ankle neutral
• Non-weight bearing 6-12 weeks depending on procedure (longer for talar neck fractures and fusions)
• Early toe range of motion
• DVT prophylaxis
• Serial radiographs to monitor healing and talar vascularity (Hawkins sign)

Complications to Document:

• Saphenous nerve injury (numbness, neuroma)
• Talar osteonecrosis (especially with talar neck fractures)
• Nonunion of medial malleolar osteotomy
• Ankle stiffness or arthritis
• Infection (2-5%)
• Wound dehiscence (higher with medial incision)