Open Avulsion of the Achilles Tendon Through the Popliteal Fossa Without Associated Fracture: A Report of a Unique Case.

We present the case of a 58-year-old woman who sustained an open avulsion of the Achilles tendon with an unusual posterior extrusion through the popliteal fossa following a run-over trauma, remarkably without associated bony injury or major arterial damage. Surgical exploration revealed a complete tendon avulsion accompanied by a small venous laceration, which was successfully repaired. The tendon was anatomically reinserted into the calcaneus using suture anchors after subcutaneous tunneling along the posterior leg. The popliteal and distal wounds were closed primarily; the posterior wound through which the tendon had extruded subsequently developed necrosis and required delayed skin grafting for definitive coverage, which healed uneventfully. At two years, the wounds were fully healed, and radiographs confirmed a maintained reinsertion without degenerative change, although residual plantarflexion weakness persisted. Functional outcomes were documented with validated and objective measures: Achilles Tendon Total Rupture Score (ATRS) 72/100 and American Orthopaedic Foot & Ankle Society (AOFAS) Ankle-Hindfoot score 77/100 (fair), with six single-leg heel raises on the injured side versus 16 contralaterally. The absence of pre-injury baseline outcome scores is acknowledged as a limitation. To our knowledge, this injury pattern has not previously been reported, and the case underscores the importance of early, multidisciplinary management in rare and complex soft-tissue trauma.