The “Diagonal” Lesion: A New Type of Combined Injury Pattern Involving the Impingement Fracture of Anteromedial Tibial Plateau and the Injury of Posterior Cruciate Ligament and Posterolateral Corner

Abstract

The purpose of this study was to investigate the incidence and clinical characteristics of the “diagonal” lesion. A total of 273 consecutive patients with combined posterolateral corner (PLC) and posterior cruciate ligament (PCL) injuries were retrospectively analyzed. All preoperative knee joint evaluations were reviewed including the computed tomography, the anteroposterior (AP) view, the lateral view, the full-length long-standing AP view, and the physical examination results with the patient under anesthesia. Twenty-six patients (9.5%) were verified as having the “diagonal” lesions. The anteromedial impingement fractures could be categorized into small (small fracture group, n = 7) and large (large fracture group, n = 19). The PCL injuries were classified into grade 2 (n = 22) and grade 3 (n = 4). The PLC injuries could be classified into type A (n = 3), type B (n = 8), and type C (n = 15) according to the Fanelli's classification system. Notably, there were 20 chronic cases. Among them, 14 (70%) had varus deformities. The proportion of patients with varus deformity in the large fracture group was significantly higher than that of the small fracture group (p = 0.026). In this study, the incidence of the “diagonal” lesions was 9.5%. Patients who had larger fracture size tended to develop subsequent varus deformity of the lower extremity. It was important for us to recognize the PCL/PLC injuries and to fully reduce the large bony fracture during the initial treatment of the “diagonal” lesions to prevent the residual instability and varus deformity.

Single-stage arthroscopic-assisted treatment of anteromedial tibial plateau fracture with posterolateral corner injury: a retrospective study

“…Up to now, the injury mechanism of this combined injury has been described as follows: under the action of forces of hyperextension and varus rotation, the medial femoral condyle and the anteromedial tibial plateau collide with each other, resulting in the fracture of the latter [ 7 , 8 , 14 – 16 ]. Simultaneously, the PLC is injured and the posterolateral joint space is widened.…”

“…Noteworthy, it has been reported that the rate of clinical missed diagnosis of the “diagonal” lesion can reach 78.6% (11 /14). Such an error can ultimately lead to knee instability and severe varus deformity of the lower extremity [ 8 ]. Consequently, for this combined injury, it is important to avoid missed diagnosis or misdiagnosis in the initial examinations of the patients.…”

“…The combined injury has a characteristic pattern in which the stress and structure of the injury are distributed diagonally from the anteromedial tibial plateau to the posterolateral tibial plateau. Accordingly, this injury pattern has been termed the “diagonal” lesion [ 8 ]. As far as we know, anteromedial tibial plateau fracture with PLC injury is a relatively rare combined injury in the clinic, and there have been few case reports regarding this injury pattern.…”

“…As far as we know, anteromedial tibial plateau fracture with PLC injury is a relatively rare combined injury in the clinic, and there have been few case reports regarding this injury pattern. It has been reported that the “diagonal” lesion accounts for 9.5% of patients with PLC and PCL injuries [ 8 ]. In clinical practice, anteromedial tibial plateau fractures are often identified, but PLC injuries are frequently missed, resulting in severe lower extremity dysfunction, such as residual instability and varus deformity [ 8 , 9 ].…”

“…It has been reported that the “diagonal” lesion accounts for 9.5% of patients with PLC and PCL injuries [ 8 ]. In clinical practice, anteromedial tibial plateau fractures are often identified, but PLC injuries are frequently missed, resulting in severe lower extremity dysfunction, such as residual instability and varus deformity [ 8 , 9 ]. In addition, there is no unified treatment scheme for this combined injury.…”