Modified Tension-Slide Technique for Endoscopy-Assisted Flexor Hallucis Longus Tendon Transfer

The rupture of the Achilles tendon (AT) usually occurs in high-caliber athletes, but low-demand patients are also are risk, mainly if they are under corticoids or quinolones. The diagnosis of the AT rupture is usually neglected, and this could result in a worse prognosis for the patient if not treated in an appropriate time. For these patients or for those with high surgical risk, an option of minimally invasive surgery remains attractive. Classical techniques consist of direct repair or augmentation with the tendon of the flexor hallucis longus as well as nonanatomical tendon transfers which can generate issues with the donor site. We present a pioneering technique that is analogous to that used for the surgical treatment of distal rupture of the biceps tendon, which consist of a transfer technique of flexor hallucis longus by extracortical fixation interference screw associated to a direct tendon reinsertion performed through a bone tunnel on the superior and posterior aspect of the calcaneus using an extracortical drilling system and an interference screw within the calcaneal tunnel. The arthroscopic approach may be technically challenging, and a high-level of arthroscopic skills are required to complete the procedure but after a learning curve it represents a feasible a safe technique.