Augmented Achilles tendon repair involves repairing a ruptured Achilles tendon with additional reinforcement using a tendon transfer — most commonly the flexor hallucis longus (FHL). It is performed for delayed presentations, re-ruptures, or when the tendon quality is poor.
An incision is made along the back of the calf. The ruptured Achilles tendon is repaired with strong sutures. The FHL tendon (which runs deep and medial to the Achilles) is harvested through the same incision, passed through a bone tunnel in the calcaneus, and secured alongside the repair to augment it. The FHL adds bulk, blood supply, and an in-phase power transfer. The operation takes one and a half to two hours.
Augmentation is recommended for neglected Achilles ruptures (more than four weeks old), re-ruptures after previous repair, ruptures in elderly or diabetic patients with poor tissue quality, and insertional ruptures with tendon degeneration.
For acute ruptures: non-augmented direct repair or functional rehabilitation. For chronic ruptures: acceptance with AFO bracing (in sedentary patients).
MRI or ultrasound to assess the gap and tendon quality. Standard pre-assessment.
Restoration of Achilles continuity and push-off power. The FHL transfer adds a functioning muscle-tendon unit that supplements the weakened Achilles. Most patients achieve functional improvement.
Six to twelve months for full recovery.
The posterior calf has limited blood supply.
Loss of big toe plantarflexion power — rarely noticed functionally.
Numbness on the outer foot.
Despite augmentation.
Particularly in smokers and diabetics.
Wound infection.
During prolonged immobilisation.
General or spinal anaesthesia with nerve block. Prone position.
Non-weight-bearing cast for six to eight weeks. Boot with graduated heel raises for four weeks. Physiotherapy for calf strengthening from ten weeks. Running at four to six months. Full recovery nine to twelve months.
Wound check at two weeks. Reviews at six weeks, three months, and six months.
Most patients do not notice significant functional loss from FHL harvest. The FDL and other toe flexors compensate. Ballet dancers may notice reduced big toe push-off.