The Medial Plantar Flap

The Medial Plantar Flap

Skin and fascia.

Innervation: Cutaneous sensor branch arising from posterior tibial nerve.

Blood supply: Medial plantar artery and perforator.

Artery: Progressively larger as one proceeds proximally, from 1 to 2 millimeters.

Vein(s): The subcutaneous venous system draining to the saphenous vein is usually used, since it is larger in caliber and much thicker walled.

Pedicle length: Can be up to 3 centimters.

Anatomy

The skin and fascia over the medial aspect of the foot is thin, providing glabrous tissue for reconstruction of a variety of small soft tissue defects. The skin is supplied by perforators from the medial plantar branch of the posterior tibial artery. The venous system is quite thin and small, and the subcutaneous system is easily incorporated into the flap and used for venous drainage. The flap length varies by defect size, with the width allowing primary closure at most 2 centimeters.  If a wider flap is necessary, the defect must be skin grafted.

The Vascular Anatomy of the Medial Foot

the vascular territory of the medial plantar flap

 

The Relationship to the Medial Foot Muscles

The perforator and the abductor hallucis and flexor brevis muscles

 

Operative Procedure

The patient is prepped and draped supine, and a well padded thigh tourniuet is used for the procedure once the flap anatomy is defined. The flap is marked on an axis between the sustenaculum of the talus and the medial aspect of the head of the first metatarsal.  The perforator from the medial plantar artery arises approximately a third of the way between the sustenaculum and the metatarsophalangeal joint.  The location of the perforator is confirmed with a pencil doppler. 

The Flap is Outlined

the axis of the flap is identified and the skin paddle outlined

The flap is raised starting at the plantar aspect first, dissecting toward the dorsal aspect of the foot while deep to the muscular fascia over the flexor hallucis brevis muscle.  As one dissects towards the dorsum of the foot, the perforator is encountered between the heads of the flexor hallucis brevis and abductor hallucis muscles.  We have found the abductor hallucis to be quite small on occasion, without a muscular presence at this level.  The perforator then appears to lie on the bone surface. 

 

The Flap is Elevated Beginning on the Plantar Aspect

The flap is elevated starting at the plantar aspect

The perforator is then dissected toward its origin on the medial plantar artery in the intermuscular space.   A pedicle length of up to 3 centimeters can be made.  When the anterior surface of the flap is elevated, the superficial venous system is spared and a subcutaneous vein is followed toward the shaphenous system to allow for a larger draining vein for this flap.  The vein on the medial plantar system can be quite small.

If desired, a cutaneous nerve branch from the posterior tibial system can be incorporated into the flap and taken with a short leash.  We prefer to use the cutaneous vein for venous drainage because it’s size and caliber make microanastomosis straight forward.  

The Flap is Isolated

The flap is isolated on the deep artery and superficial vein

Post Operative Care

The foot must be kept elevated to minimize edema.  We allow ambulation with weight bearing when all eschar on the incision or skin graft has resolved.