This joint is also not clearly defined in anatomical textbooks, such as Lanz and Wachsmuth. There is no clear statement in the Ashhurst and Bromer etiological, the Lauge-Hansen genetic or the Danis-Weber topographical fracture classification about the exact extent of the syndesmosis. However,in discussing syndesmotic injury, it seems the exact proximal and distal boundaries of the distal tibiofibular syndesmosis are not well defined. In fractures of the ankle, syndesmotic injury occurs in about 50% of type Weber B and in all of type Weber C fractures.
As widening of the ankle mortise by 1 mm decreases the contact area of the tibiotalar joint by 42%, this could lead to instability and hence early osteoarthritis of the tibiotalar joint.
This could be due to widening of the ankle mortise as a result of increased length of the syndesmotic ligaments after acute ankle sprain. Forty percent of patients still have complaints of ankle instability 6 months after an ankle sprain. In an estimated 1–11% of all ankle sprains, injury of the distal tibiofibular syndesmosis occurs. Although the syndesmosis is a joint, in the literature the term syndesmotic injury is used to describe injury of the syndesmotic ligaments.
The distal tibia and fibula form the osseous part of the syndesmosis and are linked by the distal anterior tibiofibular ligament, the distal posterior tibiofibular ligament, the transverse ligament and the interosseous ligament. A syndesmosis is defined as a fibrous joint in which two adjacent bones are linked by a strong membrane or ligaments.This definition also applies for the distal tibiofibular syndesmosis, which is a syndesmotic joint formed by two bones and four ligaments.