Treatment of Chronic Achilles Tendon Disorders with Flexor Hallucis Longus Tendon Transfer/Augmentation

Abstract

Chronic disorders of the Achilles tendon are commonly seen by the orthopaedic surgeon. In cases that are resistant to conservative treatment, a variety of surgical procedures have been utilized in the past. The indications for a previously described technique of flexor hallucis longus tendon transfer for reconstruction of chronic Achilles tendon rupture have been expanded to include further subsets of chronic Achilles tendinopathy, including rupture and tendinosis. We evaluated 20 patients (mean age 61) who underwent flexor hallucis longus transfer for treatment of chronic Achilles tendinopathy at a mean of 14 months following surgery. Our results were measured with the SF-36 survey, AOFAS Ankle-Hindfoot Scale, and Cybex strength and range of motion testing. Wound complications, tip-toe stance, and calf circumference were also assessed. There were no postoperative reruptures, tendinopathy recurrences, or wound complications. Despite a small loss of calf circumference, range of motion, and plantarflexion strength, 90% of patients scored 70 or higher on the AOFAS scale. SF-36 testing revealed significantly lower scores in the physical function category when compared with United States norms. Flexor hallucis longus tendon transfer/augmentation is a reasonable option for treatment of chronic Achilles tendinosis and rupture.

Chronic Achilles tendon rupture reconstruction using a modified flexor hallucis longus transfer

“…No hyperextension of the hallux interphalangeal joint occurred. For functional outcome, our results were close to those reported by other authors [8,12,21,24,26,27].…”

“…In a recent study, Hahn et al found a plantar flexion peak torque deficit of 35% at 60 deg/sec in a cohort of 13 patients including ten chronic AT ruptures and three tendinopathies at an average followup of 46.5 months [9]. Two other studies in the literature included both chronic rupture and Achilles tendinosis and had some limitations [18,27]. Monroe et al also recorded a 28% peak torque deficit at 30 deg/sec [18].…”

Hypertrophy of the flexor hallucis longus muscle after tendon transfer in patients with chronic Achilles tendon rupture

“…Previous studies have shown comparable results [4][5][6][7][8][9][13][14][15][16]. In the study of Wegrzyn et al [8] the postoperative deficit in plantar flexion torque averaged 28%, and 41% in the study of Wapner et al [4].…”

“…These studies also show very low failure rates after the FHLT transfer [4][5][6][7][9][10][11][12][13].…”

“…Firstly, the FHLT transfer can be carried out through a single incision, which makes the transfer a quite simple procedure. Secondly, proximity to the Achilles tendon avoids the need to disturb the lateral compartment or the neurovascular bundle, and the distal musculature of the FHL may provide some vascularity to the degenerated Achilles tendon [3,4,13]. Thirdly, the FHL is a strong ankle plantar flexor, having similar contractile axis and phase with gastrosoleus.…”