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

Abstract

The purpose of this study was to report the management and outcome of 11 patients presenting with chronic Achilles tendon (AT) rupture treated by a modified flexor hallucis longus (FHL) transfer. Seven patients presented with a neglected AT rupture, one with a chronic AT rupture associated with Achilles tendinosis and three with an AT re-rupture. AT defect after fibrosis debridement averaged 7.4 cm. In addition to FHL transfer, we performed an augmentation using the two remaining fibrous scar stumps of the ruptured AT. Functional assessment was performed using the AOFAS score and isokinetic evaluation was performed to assess ankle plantarflexion torque deficit. Follow-up averaged 79 months. Functional outcome was excellent with a significant improvement of the AOFAS score at latest follow-up. No re-rupture nor major complication, particularly of wound healing, was observed. All patients presented with a loss of active range of motion of the hallux interphalangeal joint without functional weakness during athletic or daily life activities. Isokinetic testing at 30 degrees/second and 120 degrees/second revealed a significant average decrease of 28±11% and 36±4.1%, respectively, in plantarflexion peak torque. Although strength deficit persisted at latest follow-up, functional improvement was significant without morbidity due to FHL harvesting. For patients with chronic AT rupture with a rupture gap of at least 5 cm, surgical repair using FHL transfer with fibrous AT stump reinforcement achieved excellent outcomes.

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].…”

“…This study also showed that FHLT transfer using a technique with a single incision and tendon fixation with a bone anchor, provided comparable results to those patient series where two incision technique or tendon fixation through a calcaneal bone tunnel were used [5,6,8]. A single incision technique with a fixation bone anchor or interference screw can be performed from relatively short skin incision and without exposure of the calcaneus for preparing the bone tunnel.…”

“…Some authors propose the complete excision of the degenerative Achilles due to better pain relief [4]. In recent series, however, preservation of the fibrous scar tissue has been suggested to make the tendon length assessment easier and the scar tissue is thought to work as a scaffold for the transferred FHLT [5,6,8].In fact, this scar tissue has been shown to have the capacity to form a tendon like repair tissue [16][17][18]. In our study, the tendon stumps were preserved, and possible deficits were bridged with single strand of FHL tendon only.…”

“…Several small patient series have shown good results with FHLT transfer [4][5][6][7][8][9][10][11][12]. The previous results have shown that the plantar flexion strength of the operated side cannot be fully restored, but most of the patients have been able to re-enter their previous sports interests.…”

“…Flexor hallucis longus tendon (FHLT) transfer has become a popular method for reconstructing a chronic ATR [4][5][6][7][8][9][10][11][12]. This method has many advantages.…”