Achilles Tendon Rupture
Complete disruption of the Achilles tendon, typically in middle-aged recreational athletes, causing sudden calf pain and loss of plantarflexion power.
Overview
Achilles tendon ruptures most commonly occur 2 to 6 cm proximal to the calcaneal insertion in a relatively avascular zone. Pre-existing tendinopathy, age-related collagen degeneration, and sudden eccentric loading during sport combine to produce rupture. The 'weekend warrior' demographic is classical.
Epidemiology
Incidence is around 20 to 40 per 100,000 person-years and is rising in high-income countries. Peak age is 30 to 50, with male predominance. Fluoroquinolone use and corticosteroid exposure are established risk factors.
Symptoms
Patients typically describe a sudden blow or pop at the back of the ankle and difficulty walking. Examination reveals a palpable gap, weakness of plantarflexion, and a positive Thompson (Simmonds) test with calf squeeze failing to produce plantarflexion. Residual plantarflexion by tibialis posterior and FHL may deceive the unwary.