Posteromedial Approach to Ankle Joint indications:

The posteromedial approach to ankle joint is routinely used for exploring the soft tissues that run around the back of the medial malleolus.

The posteromedial approach to the ankle joint other uses include:

  1. Open reduction and internal fixation of medial malleolus fractures.
  2. Open reduction and internal fixation of pilon fractures.
  3. Open reduction and internal fixation of posterior malleolus fractures.
  4. Release of soft tissue around the medial malleolus in the treatment of clubfoot.

Position of the Patient

 One of two positions is used in this approach:

  • Place the patient supine on the operating table. Flex the hip and knee, and place the lateral side of the affected ankle on the anterior surface of the opposite knee.
  • Place the patient in the lateral position with the affected leg nearest the table. Flex the knee of the opposite limb to get its ankle out of the way.
Posteromedial Approach to Ankle Joint

Landmarks and Incision

  • Landmarks:
    1. Medial malleolus.
    2. Achilles tendon.
  • Incision:
    • Make 10 cm longitudinal curved incision with concavity of incision pointing anterior:
      • Begin 5 cm above the medial maleollus on the posterior border of the tibia.
      • Curve incision distally following the posterior border of the medial malleolus.
      • End incision 5 cm distal to medial malleolus.
Posteromedial Approach to Ankle Joint
Posteromedial Approach to Ankle Joint Landmarks and Incision

Internervous plane

  • There is No internervous plane for posteromedial approach to ankle joint.
  • The approach is carried out between:
    • Tibialis posterior tendon.
    • Flexor digitorum muscle.
      • Both are innervated by the tibial nerve

Superficial dissection

  • Deepen the incision in line with the skin incision to enter the fat that lies between the Achilles tendon and those structures that pass around the back of the medial malleolus. If the Achilles tendon must be lengthened, identify it in the posterior flap of the wound and perform the lengthening now.
  • Identify a fascial plane in the anterior flap that covers the remaining flexor tendons. Incise the fascia longitudinally, well away from the back of the medial malleolus.

Deep dissection

There are three different ways to approach the back of the ankle joint:

  1. First, identify the flexor hallucis longus, the only muscle that still has muscle fibers at this level . At its lateral border, develop a plane between it and the peroneal tendons, which lie just lateral to it. Deepen this plane to expose the posterior aspect of the ankle joint by retracting the flexor hallucis longus medially.
  2. Second, identify the flexor hallucis longus and continue the dissection anteriorly toward the back of the medial malleolus. Preserve the neurovascular bundle by mobilizing it gently and retracting it and the flexor hallucis longus laterally to develop a plane between the bundle and the tendon of the flexor digitorum longus. This approach brings one onto the posterior aspect of the ankle joint rather more medially than does the first approach.
  3. Third, when all the tendons that run around the back of the medial malleolus (the tibialis posterior, flexor digitorum longus, and flexor hallucis longus) must be lengthened, the back of the ankle can be approached directly, because the posterior coverings of the tendons must be divided during the lengthening procedure. For all three methods, complete the approach by incising the joint capsule either longitudinally or transversely.

Approach Extension

  • The posteromedial approach to ankle joint can be extended distally by curving it across the medial border of the ankle, ending over the talonavicular joint.
  • This extension exposes both the talonavicular joint and the master knot of Henry.

Dangers

The structures at risk during posteromedial approach to ankle joint include:

  1. Tibialis posterior muscle.
  2. Flexor digitorum longus tendon.
  3. Flexor hallucis longus tendon.
  4. Posterior tibial artery and vein.
  5. Tibial nerve.

References

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