Supination trauma. A classic case

Sprains in the lateral ligaments of the ankle produce the most common ligamentous injuries of the human body. The mechanism of injury is complex, while supination represents the main component of foot movement. Classifying lateral ankle ligament injuries, many authors use a system of three degrees, which includes mild, moderate and severe sprains. Despite this scientific categories, in our opinion is the differentiation between elongation and complete ruptures of practical relevance. Under a biomechanical point of view, ligamentous trauma of the lateral ligaments lead to acute antero-lateral rotational instability (ALRI). Following the retrospective clinical study of Zwipp with 1,235 patients, in 70% of complete disruptions, the anterior talo-naviculare and fibulocalcanear ligaments are involved together. Syndesmotic injuries have been reported at a rate up to 10% of ankle sprains with deltoid ligaments at 2.5%. Rarely, the classic ankle sprain leads to injuries which affect the foot on a so called "supination fracture line". A rate of 7.4% is reported for these accompanying injuries. Therefore, clinical examination of ankle sprains should not only address on the distal tip of the fibula. Critical bony and ligamentous structures like the fifth metatarsal base, the calcaneo-cuboideal ligament, the ligaments of the anterior calcaneal process, the talus and syndesmotic ligaments have to be screened for pain and swelling. In our opinion, careful clinical examination and plain radiographs in two plains are sufficient for diagnosing ankle sprains and functional therapy.