Painful Palpation of the Tibial Insertion of the Anterolateral Ligament Is Concordant With Acute Anterolateral Ligament Injury

BACKGROUND: The anterolateral ligament (ALL) has been shown to contribute to the rotational stability of the knee. However, no clinical sign specific to ALL injury has been described. PURPOSE/HYPOTHESIS: The primary aim of this study was to determine the concordance between pain elicited upon ALL palpation and ALL injury diagnosed by ultrasonography (US). The secondary aim was to look for a relationship between ALL injury and high-grade pivot shift. We hypothesized that an ALL lesion can be diagnosed clinically in an acute knee injury by palpating its tibial insertion. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 2. METHODS: A total of 130 patients (89 men, 41 women; mean age, 27.2 ± 8.3 years) with an acute, isolated anterior cruciate ligament injury who were scheduled for ligament reconstruction were enrolled in this study. ALL palpation was carried out a mean 8.8 ± 3.2 days after injury. Preoperatively, ALL integrity was evaluated with US, and the pivot shift was determined under general anesthesia. The agreement between pain upon ALL palpation and ALL injury detected on US was determined by calculating the intraclass correlation coefficient (ICC), along with 95% CIs. RESULTS: Distal palpation of the ALL tibial insertion elicited pain in 67 (51.5%) patients, and upon US the ALL was found to be damaged in 64 (49.2%) patients. The agreement between pain over the ALL tibial insertion and the ALL being damaged on US was excellent (ICC, 0.801; 95% CI, 0.730-0.855). Moreover, the clinical test had excellent sensitivity (92%; 95% CI, 88%-97%) and specificity (88%; 95% CI, 82%-93%). The agreement between pain at the ALL distal insertion and the pivot shift was good (ICC, 0.654; 95% CI, 0.543-0.742), and ALL palpation had excellent diagnostic accuracy for identifying rotational instability (sensitivity, 88% [95% CI, 82%-93%]; specificity, 97% [95% CI, 94%-100%]). CONCLUSION: Palpation of the ALL tibial insertion highly correlates with ultrasonographic evidence of an ALL injury in the context of an acute knee injury. This simple test should become part of our standard examination when evaluating patients with acute knee injuries.