MEDIAL APPROACH TO THE MIDFOOT

USES

This approach is used for anterior tibial tendon transfers and harvesting toe flexor tendons for transfer. The proximal end of the incision is used for midfoot osteotomies and to release the plantar compartments of the foot for compartment syndromes.

ADVANTAGES

This approach goes deep to the neurovascular structures and uses the muscle of the abductor hallucis and the tendons of the toe flexors to protect the nerves and arteries.

DISADVANTAGES

There is essentially no exposure to the dorsum of the foot.

STRUCTURES AT RISK

The only significant structures at risk are the nerves and arteries. These are superficial, that is, plantar to the long flexor tendons. The anterior tibialis tendon attaches to the medial aspect of the cuneiform and base of the first metatarsal and can be transected if you are cutting down to those bones.

TECHNIQUE

The incision typically runs from the navicular tubercle distally just posterior of the midline. By putting the incision slightly posterior, it is in the arch of the foot where it will not be under pressure when wearing shoes or walking. You do not want to put it so far posterior that it will be in the weight-bearing area of the arch; 5 to 10 mm below the midline is all you should ever be.

After going through the subcutaneous tissue, taking care to protect any sensory nerves that are identified, the anterior edge of the abductor hallucis is identified and separated from the underlying bone. When it is retracted plantarward, you will see the white tendon of the flexor hallucis brevis origin, which should be released from the overlying bone in line with the bone, that is, longitudinally. When that is done, you will have more access laterally into the compartment where the flexor tendons are located. If you are too far distal, the flexor hallucis longus tendon will already be in the muscle belly of the flexor hallucis brevis and will be difficult to identify. Once identified, these tendons can be grasped and pulled into the wound for release or preparation for transfer.

The incision can also be used to dissect anteriorly and identify the insertion of the anterior tibialis tendon. These fibers run generally parallel to the metatarsal at this point, inserting into the medial cuneiform and base of the first metatarsal.