Long-term outcome of flexor hallucis longus tendon transfer for chronic Achilles tendon rupture with large defect: A retrospective series.

There are multiple surgical options for treatment of chronic Achilles tendon (AT) rupture according to the classifications and length of defect. However, no gold standard method has been confirmed, and there is no clear evidence to support the superiority of 1 procedure over others. This study aimed to evaluate the long-term clinical outcome of flexor hallucis longus tendon (FHL) transfer for chronic AT rupture with large defect. Clinical data of patients treated with FHL transfer due to chronic AT rupture between January 2009 and October 2019 were reviewed retrospectively. All cases were presented with AT rupture for more than 4 weeks after injury. The gap between ruptured ends was > 5 cm after debridement in all patients. The harvest of FHL was performed through a single incision in accordance with AT rupture debridement in all cases. Clinical outcomes were assessed with AOFAS ankle-hindfoot scale, Achilles tendon total rupture score and AOFAS hallux metatarsophalangeal-interphalangeal scale. Twenty-eight patients were followed successfully for 62.6 ± 22.2 months. According to the complete datasets obtained from 28 patients, none of the tendons re-ruptured. The AOFAS ankle-hindfoot scale and Achilles tendon total rupture score at last follow-up visit was 90.4 ± 5.7 and 89.8 ± 5.3 respectively, which revealed statistically significant improvement from the preoperative score of 61.1 ± 6.7 and 53.8 ± 8.3. The AOFAS hallux metatarsophalangeal-interphalangeal scale at last follow-up visit was 87.5 ± 6.1. The FHL transfer through a single incision for chronic AT rupture with large defect is a safe and simple method with low risk of morbidity and complications.