FRACTURE OF THE POSTERIOR ASPECT OF THE LATERAL TIBIAL PLATEAU - RADIOGRAPHIC SIGN OF ANTERIOR CRUCIATE LIGAMENT TEAR

Plain radiographs obtained in 25 patients with acute anterior cruciate ligament (ACL) tears detected with magnetic resonance imaging were re trospectively evaluated to identify associated bone lesions. Fracture of the posterior part of the lateral tibial plateau (LTP) was seen in 11 patients, impacted fracture of the lateral femoral condyle (LFC) in two, lateral tibial rim fracture (Segond fracture) in three, and avul sion fracture of the tibial attachment of the ACL in two. The latter t hree fractures have been associated with an ACL tear. Conversely, frac tures of the posterior part of the LTP have not been associated with A CL tear and are recognizable on plain radiographs. Impaction of the LF C on the LTP and avulsion of the posterior tibial capsular junction ma y account for the association of the fracture of the LTP with the acut e ACL tear. This type of fracture represents the most frequent indirec t sign of ACL tear seen on plain radiographs.