Anterolateral ligament injuries in knees with an anterior cruciate ligament tear: Contribution of ultrasonography and MRI.

OBJECTIVES: To describe the pathological appearance of the anterolateral ligament (ALL) on US and MRI in knees with an anterior cruciate ligament (ACL) tear. METHODS: This prospective study included 30 patients who had a suspected acute ACL tear. Their injured and contralateral knees were evaluated with radiography, US and MRI. Two radiologists evaluated the ALL on the MRI and US examinations. Agreement between these examiners' findings was evaluated with Cohen's kappa. RESULTS: On US examination, the ALL was found to be injured in 63% of cases (19/30; k = 0.93). The enthesis was found to be torn in 50% of cases (15/30; k = 1), with the tear located at the tibial attachment in all instances. On the MRI exam, the ALL was found to be injured in 53% of cases (16/30; k = 0.93). The enthesis was found to be torn in 13% of cases (4/30; k = 0.76), with the tear located at the tibial attachment in all instances (k = 0.93). CONCLUSION: ALL injuries that occur with ACL tears are located at the tibial enthesis. They are often associated with bone avulsion at the enthesis and are better viewed on US. KEY POINTS: • ALL injuries often occur in combination with ACL tears. • ALL injuries can be assessed with ultrasonography and MRI. • ALL injuries associated with ACL tears are located at the tibial enthesis.

Ultrasonographic Evaluation of Anterolateral Ligament Injuries: Correlation With Magnetic Resonance Imaging and Pivot-Shift Testing.

PURPOSE: (1) To compare the diagnostic ability of ultrasonography (US) and magnetic resonance imaging (MRI) to detect anterolateral ligament (ALL) injuries in anterior cruciate ligament (ACL)-deficient patients, and (2) to evaluate the correlation between ALL injury status (as determined by US and MRI) and the knee's rotational stability. METHODS: Thirty patients with an isolated ACL injury were included prospectively over a 3-month period. The condition of the ALL was evaluated by 2 experienced radiologists using both US and MRI. Rotational stability was evaluated by 2 surgeons with the pivot-shift test with patients under general anesthesia. It was classified as either negative (grades 0 and I) or positive (grades II and III). The radiologists were blinded to the knee's rotational stability, and the surgeons were blinded to the ALL's status based on the US images. The correlation between the ALL's injury status (US and MRI) and the pivot shift was determined with the Pearson χ2 test. To evaluate the reproducibility of the results, the agreement between observers was determined with the Cohen κ coefficient. RESULTS: On US, the ALL was identified and visible over its entire length in 100% of patients (30 of 30, κ = 1). The ALL was injured in 63% of patients (19 of 30, κ = 0.93). On MRI, the ALL was identified in 96% of patients (29 of 30, κ = 0.91). The ALL appeared injured in 53% of cases (16 of 30, κ = 0.93). An ALL that appeared injured on US was more often associated with a positive pivot shift than was an uninjured ALL (75% vs 39%, χ2 = 13.7, P < .05). The interobserver agreement was high for both US (κ = 0.91-1) and MRI (κ = 0.76-1). CONCLUSIONS: US is a reproducible examination for the diagnosis of ALL injury. An ALL injury is most often associated with a high pivot-shift grade. LEVEL OF EVIDENCE: Level II, prospective comparative study.

Historical perspective on the "discovery" of the anterolateral ligament of the knee.

There is a lively debate about the existence, origins and discoverer of the anterolateral ligament of the knee. The complex anatomy of the lateral aspect of the knee has made it difficult to differentiate between various structures such as the iliotibial band, capsulo-osseous layer, Kaplan's fibres and the anterolateral capsule. The "discovery" of a new anterolateral structure in 2013 was the culmination of many historical studies. In 1879, Paul Ferdinand Segond described a tibial plateau fracture in which he noted a pearly band reinforcing the joint capsule. Other anatomists had their suspicions about this ligament; it was described by Vallois in 1914 in his thesis and extensively studied by Jost in 1921. References to it can be found in comparative anatomy studies. This historical review serves as a reminder that understanding and treating knee sprains is not something new. LEVEL OF EVIDENCE: V.

Cadaveric Study Comparing the Biomechanical Properties of Grafts Used for Knee Anterolateral Ligament Reconstruction.

PURPOSE: To measure the biomechanical properties (maximum load, stiffness, and elongation) of the anterolateral ligament (ALL), gracilis, and iliotibial band (ITB) within the same subject. METHODS: Thirteen unpaired knees were used (7 women, 6 men). The donors had a mean age at death of 54 years (range: 37 to 70 years). The mechanical properties of two types of ALL grafts were evaluated: ITB and two-strand gracilis. The mechanical properties of ALL were also measured. Validated methods were used to perform the tensile tests to failure and to record the results. Student's t-test was used to compare the various samples. RESULTS: The maximum load to failure was 141 N (±40.6) for the ALL, 200.7 N (±48.7) for the gracilis, and 161.1 N (±27.1) for the ITB. Only the gracilis had a significantly higher failure load than ITB and ALL (P = .001 and P = .03). The stiffness was 21 N mm-1 (±8.2) for the ALL, 131.7 N mm-1 (±43.7) for the gracilis, and 39.9 N mm-1 (±6) for the ITB. The elongation at failure was 6.2 mm (±3.2) for the ALL, 19.9 mm (±6.5) for the gracilis, and 20.8 mm (±14.7) for the ITB. CONCLUSIONS: The gracilis had the highest maximum load to failure. The ITB's mechanical properties most closely resemble those of the ALL. CLINICAL RELEVANCE: The biomechanical properties of each potential ALL graft can be factored in when deciding which type of graft to use.

Ultrasonographic Identification of the Anterolateral Ligament of the Knee.

PURPOSE: To determine ultrasonography's sensitivity for identifying the anterolateral ligament (ALL). METHODS: A descriptive study of 18 cadaveric knees was performed. Ultrasonography was used to locate any anterolateral structures at the knee that could correspond to the ALL. The structure's length and relation with other notable anatomic landmarks (fibular head, Gerdy tubercle, joint line, lateral femoral epicondyle, popliteus tendon insertion) were quantified. The ultrasonography measurements were validated by dissecting each knee. The sensitivity of ultrasonography for detecting the ALL and the agreement between the ultrasonographic and cadaveric measurements (Cohen κ) were determined by statistical analysis. RESULTS: The ALL was found in all 18 cadaveric knees and corresponded anatomically to the ultrasonographic descriptions. Ultrasonography had 100% sensitivity for detecting the presence of the ALL. The ALL's insertion on the lateral femoral condyle was, on average, 12.08 mm (SD, 4 mm; range, 7 to 15 mm) proximal and posterior to the lateral femoral epicondyle and 20.5 mm (SD, 3 mm; range, 16 to 24 mm) proximal to the middle of the popliteus tendon insertion. The ALL inserted onto the tibia, midway between the Gerdy tubercle and the fibular head; the distance between the midpoint of the tibial insertion and middle of the Gerdy tubercle was 19.05 mm (SD, 2.1 mm; range, 15 to 25 mm), and the distance was 19.13 mm (SD, 2.3 mm; range, 14 to 23 mm) to the tip of the fibular head. The agreement between the ultrasonographic and cadaveric findings was excellent (Cohen κ coefficient between 0.88 and 0.94). CONCLUSIONS: Ultrasound imaging is a suitable tool for identifying the ALL of the knee, and it allowed for a detailed analysis of the entire ALL in all 18 knees. However, its ability to evaluate any injuries to the ALL must still be shown. CLINICAL RELEVANCE: Ultrasonography can be used to confirm the integrity of the ALL.

How to Test the Anterolateral Ligament With Ultrasound.

Ultrasonography (US) is a nonirradiating, low-cost, real-time imaging modality that has very good spatial resolution. US can be used to view the anterolateral ligament (ALL) and injuries to the ALL. Several authors have sought to analyze the anterolateral aspect of the knee using US with varying luck. All of them analyzed the ALL statically only. The goal of this Technical Note is to describe in detail the technique that we use to analyze the anterolateral aspect of the knee in patients with an anterior cruciate ligament tear. We use a simple technique that starts by locating the tibial end of the ALL. The lateral inferior genicular artery is a reliable landmark in this context. The analysis is dynamic in addition to being static. To determine if the ALL is injured, we look for a lack of tension on the ALL when the knee is internally rotated and for a Segond fracture. We believe that it is essential to start evaluating the ALL by its tibial end. US analysis of the ALL forms the basis for developing an appropriate "à la carte" treatment for the patient's injury.