Minimally invasive method of harvesting the flexor digitorum longus tendon: A cadaver study

Background: The flexor digitorum longus (FDL) tendon is harvested for use in the reconstruction of dysfunctional adjacent tendons such as the posterior tibial and the Achilles tendons. The approach to harvest the FDL tendon in the midfoot region is through an incision along the medial border of the foot. This approach involves dissection quite deep in the foot across neurovascular structures in the vicinity placing them at risk. The purpose of this cadaver study was to test the feasibility and safety of a minimally invasive technique, and also to define the relevant topographical surface and deeper surgical anatomy. Methods: In 83 cadaver feet, the FDL tendon was harvested proximally in the hindfoot after it was cut through a small plantar incision in the midfoot. All the tissues superficial to the FDL tendon were then reflected to check for damage to the adjacent neurovascular structures. Measurements were obtained to define the location of the point of division of the FDL tendon in relation to the plantar surface of the foot and the adjacent neurovascular structures. Results: In all of the 83 feet it was possible to harvest the FDL using this technique. In 11 feet (13.25%), a connecting band to the flexor hallucis longus tendon (FHL) required division. No damage was apparent to the adjacent neurovascular structures. The FDL division was located topographically on the plantar surface of the foot, approximately midway between the back of the heel and the base of the second toe and at this midpoint, about two-thirds of the width medially from the lateral border of the foot. Conclusions: The FDL tendon can be harvested in the hindfoot after its division through a small plantar incision in the midfoot. Surface anatomy guides placement of the plantar incision over the FDL division. Clinical relevance: The plantar approach when compared to the medial approach for harvesting the FDL tendon in the midfoot may be associated with a smaller incision, minimal dissection, lesser risk to adjacent neurovascular structures and lesser morbidity.