Reconstruction of chronic Achilles tendon ruptures using a doubled peroneus longus tendon free graft and interference screw fixation: a technical note

BACKGROUND: The surgical management of chronic Achilles tendon ruptures (CATR) with significant tissue defects (Myerson Type II/III) presents a clinical challenge. Traditional reconstructive methods relying on free hamstring autografts or flexor hallucis longus transfers are often limited by donor-site morbidity, infection risks, or are unavailable in patients with a history of anterior cruciate ligament (ACL) reconstruction. This technical note describes a refined, tissue-preserving surgical technique utilising a doubled free autologous peroneus longus (PL) tendon graft. METHODS: Under regional anaesthesia and thigh tourniquet control, a targeted 4 cm mini-open lateral incision is performed. The PL tendon is identified, harvested proximally using a tendon stripper, and a concomitant distal side-to-side tenodesis of the PL to the PB is performed to minimise eversion weakness. On the back table, the free PL autograft is doubled to achieve a 10 mm diameter construct. A calcaneal tunnel is drilled using progressive reaming. The free graft is routed through the proximal Achilles stump, passed subcutaneously, and drawn through the calcaneus. Final rigid stabilisation is secured with a 10 × 30 mm Bio-Interference Screw (Arthrex®) with the ankle held in maximum forced equinus to ensure optimal tensioning. Postoperatively, a 4-phase accelerated protocol begins with 3 weeks in a short-leg fibreglass cast under protected weight-bearing. RESULTS/TECHNICAL ADVANTAGES: This technique achieves reliable primary mechanical stability, allowing for early protected loading while minimising soft-tissue stripping in the hypovascular distal Achilles watershed area. The free PL autograft provides an adequate structural match, and complements the translational framework of the Soft Tissue Healing Diamond (ST-Diamond) concept. Furthermore, this approach serves as a potential alternative for middle-aged patients who have a history of prior ACL reconstruction using hamstring autografts, avoiding contralateral donor-site morbidity or the use of allografts. CONCLUSION: The described mini-open free peroneus longus autograft reconstruction with interference screw fixation represents a cautious, reproducible, and biologically sound salvage option for large chronic Achilles tendon defects, balancing mechanical stability with minimal surgical morbidity.