Lateral Notch Sign Research Articles

A 30-year-old woman with acute knee injury

See page 1390 for the question. Additional MRI showed a prominent bone contusion at the location of the radiographically visible depression in the lateral femur condyle (figure 2). Remarkably, also a bone bruise was observed at the posterolateral side of the tibial plateau (figure 3). Furthermore, an empty notch sign, full disruption of the anterior cruciate ligament (ACL), oedema around an intact medial collateral ligament and an accompanying tear of the posterior horn of the lateral meniscus were also observed on MR (figure 4). The increased depth of the femoral notch, visible on the lateral plain knee radiograph, is an infrequent but characteristic radiological image, known as ‘lateral (femoral) notch sign’. Figure 2 Sagittal MR fat suppressed PD-weighted image shows marrow oedema (solid arrow) around a deep femoral sulcus in the lateral femoral condyle. PD, proton density. Figure 3 Coronal short T1 inversion recovery (STIR) heavily T2-weighted MRI shows bone bruise (solid arrow) on the posterolateral side of the tibial plateau as well. Figure 4 Sagittal non-fat-suppressed PD-weighted images show an anterior cruciate ligament tear (A, solid white arrow) and a tear of the posterior horn of the lateral meniscus, reaching the surface (B, white arrow). PD, proton density. The ‘lateral notch sign’ is an abnormally deep lateral condylopatellar sulcus due to a compression fracture of the lateral femoral condyle, which has been described as an indirect sign of ACL rupture. It is caused by impression of the lateral femoral condyle against the posterior lateral corner of the tibial plateau, during subluxation in the case of acute ACL tear, similar to a Hill-Sachs lesion of the humerus caused by anterior dislocation of the glenohumeral joint. This impaction causes a pattern of injuries well known as ‘kissing contusions’, which are usually radiographic occult injuries to the cartilage and bone. In 92–100% of patients with acute ACL rupture, …

Paper 117: The “Lateral Notch Sign” in ACL Injury: Incidence, Mechanism, Morphology and Correlation

IntroductionThe “lateral notch sign”, an impression fracture visible on a lateral knee radiograph has been described as an indirect sign of ACL rupture. However, surprisingly few papers have been published, so compared to the “Segond sign” (which is significantly more infrequent) the “lateral notch sign” is relatively unknown amongst orthopaedic surgeons. The “lateral notch sign” is caused by an impression of the lateral femoral condyle against the posterior superior lateral corner of the tibial plateau during the subluxation in case of an ACL rupture.It was the aim of the study to analyze and compare radiographs and MRIs' of patients with ACL rupture according to frequency, location and morphology of the “lateral notch sign”. In addition, the correlations of the cause of injury and accompanying injuries of the lateral meniscus have been calculated.

Arthroscopic treatment of a large lateral femoral notch in acute anterior cruciate ligament tear

A 24-year-old professional soccer player suffered an acute anterior cruciate ligament tear associated with a radiologically evident impression fracture of the lateral femoral condyle, the so-called "lateral femoral notch sign". Following MRI validation of the injury with detection of an additional lateral meniscus tear, arthroscopy was carried out 3 days after the injury. Due to the extended impression of about 5 mm, arthroscopically assisted closed reduction of the depression fracture was performed. A 3.2 mm tunnel was drilled at the lateral femoral condyle in a supero-inferior direction using an ACL tibial guide and the depressed area could be restored using an elevator. The resulting subchondral bone defect in the femoral condyle was filled with freeze-dried human cancellous bone allograft. As a one-stage procedure ACL reconstruction was carried out using a hamstring tendon technique. At 1-year follow up the patient has returned to full sporting function, including playing soccer with a radiographically reduced lateral femoral notch sign.

The lateral notch sign associated with acute anterior cruciate ligament disruption.

We prospectively studied all of the patients with anterior cruciate ligament disruptions who sought treatment at the senior author's office during a 36-month period. Plain radiographs identified depressions measuring 2 mm or more in the lateral femoral condyle (lateral notch sign) in 9 of 120 knees (7.5%) with acute anterior cruciate ligament disruption and in 2 of 44 knees (4.5%) with chronic pivot shift instability. The depression ranged from 2 to 6 mm deep and from 20 to 25 mm long. The mean age for acutely injured patients with lateral notch signs was 17.2 years, 6 years younger than the mean age of the group with acutely injured anterior cruciate ligaments as a whole. Ten of the 11 patients (91%) with lateral notch signs were men, and all 6 patients with depressions shallower than prior descriptions of the notch sign were men. In contrast, 67% (N = 110) of the entire group of patients who had anterior cruciate ligament disruption were men. Ten of the 11 patients (91%) with the lateral notch signs and 4 of the 6 patients (66%) with minimal depressions also had lateral meniscus tears, while 58 of 147 patients (39%) without lateral femoral condyle depression had lateral meniscus tears. Previous reports that the lateral notch is a sign of chronic anterior cruciate ligament deficiency with recurrent pivot shifts are not supported by the number of prospectively recognized acute lateral femoral notch signs in this series. We found the presence of radiographic changes in the lateral femoral condyle to have statistically significant correlations with young age, male sex, lateral meniscus tears in general and anterior-horn lateral meniscus tears specifically, and lateral femoral chondral lesions.