Surgical anatomy for a new minimally invasive approach to harvest the flexor digitorum longus tendon: A cadaver study

Abstract 

Aim

The purpose of this cadaver study was to test feasibility and safety of a new technique for harvesting the FDL tendon through a plantar incision placed directly overlying the FDL division and to define the relevant surgical anatomy.

Methods

In eight cadaver feet the FDL tendon was exposed in the midfoot through a plantar incision. In four of these feet this was done after localization of the FDL division site using a probe inserted through a wound in the hindfoot within the sheath of FDL tendon. The exact location was measured in relation to the geometry of the foot and was found to be midway between the back of the heel and the base of the second toe and about 4cm medial to the lateral border of the foot. Using these determinants FDL was exposed on the contralateral matching four feet without use of the probe. The FDL tendon was divided and pulled proximally and the length of the tendon was determined.

Results

The FDL division lies midway between the back of the heel and the base of the second toe and about 3.7cm medial to the lateral border of the foot. The medial and the lateral plantar neurovascular bundles are, respectively, about 0.43cm and 0.86cm away from the FDL division. The average length of the retrieved tendon was about 9cm.

Conclusions

This cadaver study suggests that the FDL tendon can be safely harvested through a plantar incision. The adjacent neurovascular structures remained undamaged. Plantar surface anatomy guides placement of the plantar incision so that the incision can overlie directly over the FDL division.

Keywords: Flat foot, Flexor digitorum longus, Tendon, Planovalgus foot deformity, Posterior tibial tendon