Combined ACL reconstruction and Segond fracture fixation fails to abolish anterolateral rotatory instability

The Segond Fracture (SF) is considered pathognomonic of an anterior cruciate ligament (ACL) tear. However, the precise anatomy of the soft tissue attachments responsible for avulsion of SF’s have been a cause of controversy in the literature with some authors suggesting that they occur due to avulsion of the iliotibial band (ITB) and others reporting that it is the anterolateral ligament (ALL). A thirty-one-year-old male patient presented with a work-related injury to his right knee that resulted in ACL tear and a SF. Open SF fixation and arthroscopic ACL reconstruction were performed. The anatomical dissection performed in order to fix the SF demonstrated that the avulsion had occurred as a result of the tibial attachment of the ALL with a completely intact ITB. At one-year postoperative follow-up, the ACL graft had restored anterior tibial translation to within normal limits. However, residual rotational knee laxity was observed in the absence of any other secondary restraint lesions. This is an important finding because it highlights that patients with SF may be at increased risk of persistent instability after ACL reconstruction even in the presence of an anatomically correctly positioned and well-functioning ACL graft. It also demonstrates that anatomical reduction and fixation of SF at the time of ACLR does not necessarily restore normal knee kinematics and consideration should be given to recession of the fixation or augmentation of the ALL when dealing with this injury pattern. A thirty-one-year-old male patient presented with a work-related injury to his right knee that occurred when he was struck by a truck at low speed. The mechanism of injury involved anterior tibial translation, varus stress and internal rotation. Physical examination revealed the following findings: large joint effusion, range of motion 0-100o, no neurological or vascular deficit, positive Lachman’s test with a soft end-point, a side-to-side anteroposterior laxity difference of 7mm measured by the Rolimeter device (Aircast, Europe), and a grade II pivot-shift (clunk). Plain radiographs demonstrated a fracture of the anterolateral border of the tibial plateau (figure 1A) and MRI showed a complete anterior cruciate ligament (ACL) rupture with a concomitant 3x16x18mm fracture of the anterolateral tibial border (figure 1B). MRI did not demonstrate any other intra- or extra-articular injuries. Specifically, there was no evidence of injury to any other ligamentous structure, chondral injury, lateral condyle notch sign, or any type of meniscal tear.