Biotenodesis screw for fixation of FDL transfer in the treatment of adult acquired flatfoot deformity

Background: In stage II PTTD, flexor digitorum longus (FDL) tendon transfer with an adjunctive bony procedure is the most common method of surgical correction. This paper presents an alternative method of fixation with a biotenodesis interference screw (Arthrex Biotenodesis Screw System) that allows proper tensioning of the FDL tendon transfer. Materials and Methods: We retrospectively reviewed 25 consecutive patients who underwent FDL tendon transfer utilizing a biotenodesis interference screw. Intraoperative stability was noted and any loss of correction was assessed postoperatively. Results: Stable fixation was achieved in 24 of the 25 patients who underwent FDL tendon transfer for PTTD. We were not able to achieve stable fixation in one patient due to improper placement of the bone tunnel. This was recognized intraoperatively and did not affect the final outcome. Conclusion: This method is technically easier to perform than the recommended technique by the manufacturer. It can be performed through a slightly smaller incision without disrupting the normal interconnections between flexor hallucis long (FHL) and FDL tendon at the Knot of Henry.