Endoscopic Flexor Hallucis Longus Transfer for the Management of Acute Achilles Tendon Ruptures: A Prospective Case Series Report With a Minimum of 18 Months’ Follow-Up

Abstract

Acute Achilles tendon rupture can be treated either surgically or nonsurgically. The flexor hallucis longus (FHL) has been used successfully in patients with large chronic Achilles tendon defects. The aim of this study was to describe the clinical outcomes of isolated endoscopic FHL transfer in patients with acute Achilles tendon ruptures at a minimum follow-up of 18 months. Fifty-six male patients with an average age of 36.3 years who underwent endoscopic FHL transfer as a treatment for acute Achilles tendon ruptures were included. Follow-up was for a mean (± standard deviation) of 27.5 ± 7.29 months. At 18 months postoperatively, the Achilles tendon total rupture score mean was 95 ± 4.26, and the American Orthopaedic Foot and Ankle Society score was a mean of 96.4 ± 4.31. The median value for FHL tendon dynamometry on the surgical side was 95.72 (range 70.1 to 142), and 100.7 (range 68 to 161) for the nonoperated side. Mean ankle plantarflexion strength at 18 months was 19.19 ± 2.55 kg • m compared with the uninjured side of 19.27 ± 2.16 kg • m. Relative Achilles tendon resting angle showed a mean of –0.25° ± 2.43°. Magnetic resonance imaging performed at a minimum of 18 months postoperatively showed a homogeneous continuous Achilles tendon signal for 43 patients and heterogeneous signal intensity in 13 patients (23.21%). No patients reported any great toe complaints or symptomatic deficits of flexion strength. No neurovascular or skin complications were encountered. The current study demonstrated satisfactory and comparable results with minimal complications when using the endoscopic FHL tendon transfer in surgical management of acute Achilles tendon ruptures, compared with the currently used methods.