Outcomes of Flexor Digitorum Longus (FDL) Tendon Transfer for the Treatment of Chronic Achilles Tendinopathy

Category: Hindfoot, Sports Introduction/Purpose: Flexor hallucis longus (FHL) tendon transfer is a common surgical technique used for augmentation during the surgical treatment of chronic Achilles tendinopathy and reconstruction. Flexor digitorum longus (FDL) tendon transfer represents a viable surgical alternative for patients with failed FHL transfers or athletes where compromise of the hallux push off strength could negatively impact their level of activity. There is no reported clinical outcome data about this technique in the current literature. Our study describes the clinical and functional results after FDL tendon transfer for the treatment of patients with chronic Achilles tendinopathy. Methods: We retrospectively assessed prospectively collected data on patients that underwent FDL tendon transfer in the treatment of chronic Achilles tendinopathy (March 2012 - March 2015). Charts were reviewed for clinical data, associated treatments and complications. Preoperative assessment included the Visual Analogue Score (VAS), SF-36 health status survey and the lower extremity functional scale (LEFS). At final follow up we evaluated pain level, range of motion of the ankle and the toes, ability to perform single leg raise and toe walking, calf atrophy and complications. Postoperative outcomes were assessed by Visual Analogue Score (VAS), SF-36 health survey, Lower Extremity Functional Scale (LEFS), Foot Function Index (FFI), VISA-A score and the Foot and Ankle Ability Measure (FAAM). Fifteen patients (seventeen feet), 6 males and 9 females, mean age of 53.6 years (27- 76 years) and an average body mass index of 31.4 kg/m2 (20.5 to 45.4 kg/m2) were included in the study. Results: Mean follow-up was 27.5 months (15-49). Four patients (6 feet) had prior surgeries, including two patients with failed FHL transfer. We found significant clinical improvement when comparing pre-operative and postoperative VAS scores (6.0±3.3 versus 1±1.36; p<0.001), SF-36 physical component summary (28.2±10.7 versus 45.0±11.1; p<0.002) and LEFS (36.4±22 versus 57.9±20.5; p