Marcelo Batista Bonadio

Anatomy and Histology of the Knee Anterolateral Ligament

Background: Reconstruction of the anterior cruciate ligament (ACL) is one of the most common procedures in orthopaedic surgery. However, even with advances in surgical techniques and implants, some patients still have residual anterolateral rotatory laxity after reconstruction. A thorough study of the anatomy of the anterolateral region of the knee is needed. Purpose: To study the anterolateral region and determine the measurements and points of attachments of the anterolateral ligament (ALL). Study Design: Descriptive laboratory study. Methods: Dissections of the anterolateral structures of the knee were performed in 20 human cadavers. After isolating the ALL, its length, thickness, width, and points of attachments were determined. The femoral attachment of the ALL was based on the anterior-posterior and proximal-distal distances from the attachment of the lateral collateral ligament (LCL). The tibial attachment point was based on the distance from the Gerdy tubercle to the fibular head and the distance from the lateral tibial plateau. The ligaments from the first 10 dissections were sent for histological analysis. Results: The ALL was found in all 20 knees. The femoral attachment of the ALL at the lateral epicondyle averaged 3.5 mm distal and 2.2 mm anterior to the attachment of the LCL. Two distal attachments were observed: one inserts into the lateral meniscus, the other between the Gerdy tubercle and the fibular head, approximately 4.4 mm distal to the tibial articular cartilage. The mean measurements for the ligament were 37.3 mm (length), 7.4 mm (width), and 2.7 mm (thickness). The histological analysis of the ligaments revealed dense connective tissue. Conclusion: The ALL is consistently present in the anterolateral region of the knee. Its attachment to the femur is anterior and distal to the attachment of the LCL. Moving distally, it bifurcates at close to half of its length. The ALL features 2 distal attachments, one at the lateral meniscus and the other between the Gerdy tubercle and the fibular head. Clinical Relevance: The ALL may be important in maintaining normal rotatory limits of knee motion; ALL rupture could be responsible for rotatory laxity after isolated intra-articular reconstruction of the ACL.

Radiographic Landmarks for Locating the Femoral Origin and Tibial Insertion of the Knee Anterolateral Ligament

Background: Recent anatomic studies have confirmed the presence of a true ligament structure, the anterolateral ligament (ALL), in the anterolateral region of the knee. This structure is involved in the rotatory instability of the knee and might explain why some isolated reconstructions of the anterior cruciate ligament result in a residual pivot shift. Therefore, when considering the least invasive method for reconstruction of this structure, it is important to identify the corresponding bony landmarks on radiographic images. Purpose: To establish radiographic femoral and tibial landmarks for the ALL in frontal and lateral views. Study Design: Descriptive laboratory study. Methods: Ten unpaired cadaver knees were dissected. The attachments of the ALL were isolated and its anatomic parameters were quantified. Its origin and insertion were marked with a 2-mm-diameter metallic sphere, and radiographs were taken from frontal and lateral views. The obtained images were analyzed and the ALL parameters established. Results: The origin of the ALL in the lateral view was found at a point an average ± SD of 47.5% ± 4.3% from the anterior edge of the femoral condyle and about 3.7 ± 1.1 mm below the Blumensaat line. In the frontal view, the origin was about 15.8 ± 1.9 mm from the distal condyle line. The ALL insertion was an average of 53.2% ± 5.8% from the anterior edge of the lateral tibial plateau in the lateral view and 7.0 ± 0.5 mm below the lateral tibial plateau in the frontal view. In anatomic dissections, the origin of the ALL was 1.9 ± 1.4 mm anterior and 4.1 ± 1.1 mm distal to the lateral collateral ligament, and the insertion was 4.4 ± 0.8 mm below the lateral tibial plateau cartilage. Conclusion: The ALL origin on an absolute lateral radiograph of the knee is approximately 47% of the anterior-posterior size of the condyle and 3.7 mm caudal to the Blumensaat line. In a frontal radiograph, the ALL is 15.8 mm from the posterior bicondyle line. The ALL insertion is approximately 53.2% of the anterior-posterior size of the plateau in the lateral view and 7.0 mm below the articular line in the frontal view. Clinical Relevance: Knowledge of the anatomic landmarks of the ALL on radiography will permit minimally invasive surgical reconstruction with lower morbidity.

Combined Intra- and Extra-articular Reconstruction of the Anterior Cruciate Ligament: The Reconstruction of the Knee Anterolateral Ligament

We present a new technique for the combined intra- and extra-articular reconstruction of the anterior cruciate ligament. Intra-articular reconstruction is performed in an outside-in manner according to the precepts of the anatomic femoral tunnel technique. Extra-articular reconstruction is performed with the gracilis tendon while respecting the anatomic parameters of the origin and insertion points and the path described for the knee anterolateral ligament.

Evaluation of the Length and Isometric Pattern of the Anterolateral Ligament With Serial Computer Tomography

Background: Recent anatomical studies have identified the anterolateral ligament (ALL). Injury to this structure may lead to the presence of residual pivot shift in some reconstructions of the anterior cruciate ligament. The behavior of the length of this structure and its tension during range of motion has not been established and is essential when planning reconstruction. Purpose: To establish differences in the ALL length during range of knee motion. Study Design: Descriptive laboratory study. Methods: Ten unpaired cadavers were dissected. The attachments of the ALL were isolated. Its origin and insertion were marked with a 2 mm–diameter metallic sphere. Computed tomography scans were performed on the dissected parts under extension and 30°, 60°, and 90° of flexion; measurements of the distance between the 2 markers were taken at all mentioned degrees of flexion. The distances between the points were compared. Results: The mean ALL length increased with knee flexion. Its mean length at full extension and at 30°, 60°, and 90° of flexion was 37.9 ± 5.3, 39.3 ± 5.4, 40.9 ± 5.4, and 44.1 ± 6.4 mm, respectively. The mean increase in length from 0° to 30° was 3.99% ± 4.7%, from 30° to 60° was 4.20% ± 3.2%, and from 60° to 90° was 7.45% ± 4.8%. From full extension to 90° of flexion, the ligament length increased on average 16.7% ± 12.1%. From 60° to 90° of flexion, there was a significantly higher increase in the mean distance between the points compared with the flexion from 0° to 30° and from 30° to 60°. Conclusion: The ALL shows no isometric behavior during the range of motion of the knee. The ALL increases in length from full extension to 90° of flexion by 16.7%, on average. The increase in length was greater from 60° to 90° than from 0° to 30° and from 30° to 60°. The increase in length at higher degrees of flexion suggests greater tension with increasing flexion. Clinical Relevance: Knowledge of ALL behavior during the range of motion of the knee will allow for fixation (during its reconstruction) to be performed with a higher or lower tension, depending on the chosen degree of flexion.

Evaluation of the anterolateral ligament of the knee by means of magnetic resonance examination

Objective To evaluate the presence of the anterolateral ligament (ALL) of the knee in magnetic resonance imaging (MRI) examinations. Methods Thirty-three MRI examinations on patients’ knees that were done because of indications unrelated to ligament instability or trauma were evaluated. T1-weighted images in the sagittal plane and T2-weighted images with fat saturation in the axial, sagittal and coronal planes were obtained. The images were evaluated by two radiologists with experience of musculoskeletal pathological conditions. In assessing ligament visibility, we divided the analysis into three portions of the ligament: from its origin in the femur to its point of bifurcation; from the bifurcation to the meniscal insertion; and from the bifurcation to the tibial insertion. The capacity to view the ligament in each of its portions and overall was taken to be a dichotomous categorical variable (yes or no). Results The ALL was viewed with signal characteristics similar to those of the other ligament structures of the knee, with T2 hyposignal with fat saturation. The main plane in which the ligament was viewed was the coronal plane. Some portion of the ligament was viewed clearly in 27 knees (81.8%). The meniscal portion was evident in 25 knees (75.7%), the femoral portion in 23 (69.6%) and the tibial portion in 13 (39.3%). The three portions were viewed together in 11 knees (33.3%). Conclusion The anterolateral ligament of the knee is best viewed in sequences in the coronal plane. The ligament was completely characterized in 33.3% of the cases. The meniscal portion was the part most easily identified and the tibial portion was the part least encountered.

Correlation of Magnetic Resonance Imaging With Knee Anterolateral Ligament Anatomy: A Cadaveric Study.

Background: Anatomic and magnetic resonance imaging (MRI) studies have recently characterized the knee anterolateral ligament (ALL). So far, no study has focused on confirming whether the evaluated MRI parameters truly correspond with ALL anatomy. Purpose: To assess the validity of MRI in detecting the ALL using an anatomic evaluation as reference. Study Design: Descriptive laboratory study. Methods: A total of 13 cadaveric knees were subjected to MRI and then to anatomic dissection. Dissection was performed according to previous anatomic study methodology. MRIs were performed with a 0.6- to 1.5-mm slice thickness and prior saline injection. The following variables were analyzed: distance from the origin of the ALL to the origin of the lateral collateral ligament (LCL), distance from the origin of the ALL to its bifurcation point, maximum length of the ALL, distance from the tibial insertion of the ALL to the articular surface of the tibia, ALL thickness, and ALL width. The 2 sets of measurements were analyzed using the Spearman correlation coefficient (ρ) and Bland-Altman plots. Results: The ALL was clearly observed in all dissected knees and MRI scans. It originated anterior and distal to the LCL, close to the lateral epycondile center, and showed an anteroinferior path toward the tibia, inserting between the Gerdy tubercle and the fibular head, around 5 mm under the lateral plateau. The ρ values tended to increase together for all studied variables between the 2 methods, and all were statistically significant, except for thickness (P = .077). Bland-Altman plots showed a tendency toward a reduction of ALL thickness and width by MRI compared with anatomic dissection. Conclusion: MRI scanning as described can accurately assess the ALL and demonstrates characteristics similar to those seen under anatomic dissection. Clinical Relevance: MRI can accurately characterize the ALL in the anterolateral region of the knee, despite the presence of structures that might overlap and thus cause confusion when making assessments based on imaging methods.

Anatomical study on the anterolateral ligament of the knee

Objective Describe the knee anterolateral ligament (ALL) and establish its anatomical marks of origin and insertion. Methods Dissection of the anterolateral aspect of the knee was performed in six cadavers. After isolation of the ALL, its lenght, width and thickness were measured as its places of origin and insertion. The ALL origin was documented in relation to the lateral collateral ligament (LCL) origin and the insertion was documented in relation to the Gerdy tubercle, fibullar head and lateral meniscus. After the first two dissections, the ligament was removed and sent to histologycal analysis. Results The ALL was clearly identified in all knees. Its origin in the lateral epycondile was on average 0.5 mm distal and 2.5 mm anterior to the LCL. In the tibia, two insertions were observed, one in the lateral meniscus and another in the proximal tibia, about 4.5 mm distal to the articular cartilage, between the Gerdy tubercle and the fibullar head. The average measures obtained were: 35.1 mm lenght, 6.8 mm width and 2.6 mm thickness. In the ligament histological analysis, dense connective tissue was observed. Conclusion The ALL is a constant structure in the knee anterolateral region. Its origin is anterior and distal to the LCL origin. In the tibia, it has two insertions, one in the lateral meniscus and another in the proximal tibia between the Gerdy tubercle and the fibullar head.

Correlation between magnetic resonance imaging and physical exam in assessment of injuries to posterolateral corner of the knee

OBJECTIVE: Evaluate the correlation between magnetic resonance imaging, clinical examination and intraoperative identification of posterolateral corner injuries of the knee. METHODS: We compared the findings of physical examination under anesthesia and intraoperative findings as the gold standard for the posterolateral corner injury with the reports of the MRIs of patients who underwent reconstruction of the posterolateral corner. Thus, we evaluated the use of MRI for the diagnosis of lesions. RESULTS: We found a sensitivity of 100% in lesions of the anterior cruciate ligament (ACL), 86.96% in lesions of the posterior cruciate ligament (PCL), 57.58% in lesions of the lateral collateral ligament (LCL) and 24.24 % in tendon injuries of the popliteal muscle (PMT). CONCLUSION: Posterolateral corner injury is difficult to visualize and interpret; therefore, MRI imaging should not be used alone for diagnosis. Level of Evidence II. Diagnostic Studies.

Combined Reconstruction of the Anterior Cruciate Ligament and Posterolateral Corner With a Single Femoral Tunnel

Combined injuries involving the anterior cruciate ligament (ACL) and posterolateral corner (PLC) occur in approximately 10% of complex knee injuries. The current tendency is to reconstruct both the ACL and the structures of the PLC. In injuries involving multiple ligaments, a potential problem in the reconstruction is the convergence of tunnels in the lateral walls of the femur. As a solution to this problem, we propose a combined technique for reconstruction of the ACL and PLC with a single tunnel in the lateral femoral wall. Combined ACL/PLC reconstruction is performed with 2 semitendinosus tendons and 1 gracilis tendon. The technique consists of making a tunnel in the lateral wall of the femur, from the outside in, at the isometric point, for reconstruction of the collateral ligament and popliteus tendon, and emerging in the joint region at the anatomic point of the ACL reconstruction. The graft is passed from the tibia to the femur with the double gracilis tendon and the simple semitendinosus tendon; the remaining portions are left for reconstruction of the structures of the PLC. This technique is very effective in terms of minimizing the number of tunnels, but it does rely on having grafts of adequate size.

Anterolateral Ligament of the Fetal Knee: An Anatomic and Histological Study.

Background: The anterolateral ligament (ALL) of the knee has recently been described in detail. Most studies of the ALL have been conducted in adults; therefore, little is known about the anatomy and histology of the ALL in younger patients, and nothing is known about the fetal presence of the ALL. Purpose: To evaluate the ALL in human fetuses to determine its presence or absence and to describe its microscopic anatomy and histological features compared with the findings of studies conducted in adults. Study Design: Descriptive laboratory study. Methods: Twenty human fetal cadaveric specimens were used. The mean age of the fetuses was 28.64 ± 3.20 weeks. The ALL was dissected in the anterolateral region of the knee, and its anatomic parameters, including its origin, insertion, and path in relation to known adjacent anatomic landmarks, in addition to its length, width, and thickness over the path toward the tibia, were measured. After dissection, the ALL was removed en bloc with a portion of the lateral meniscus for histological analysis of 4-μm sections, hematoxylin and eosin staining, and immunohistochemical staining for type I collagen. Results: The ALL was located in all dissected knees. Its origin was located at a mean distance of 1.87 mm from the origin of the lateral collateral ligament, with variations from the center of the lateral epicondyle to posterior and proximal to it, and it exhibited an anterior-inferior path toward the tibia, an insertion in the lateral meniscus approximately 2.08 mm anterior to the popliteal tendon, and another insertion in the tibia between the Gerdy tubercle and the fibular head at 2.46 mm below the articular cartilage. The histological sections of the ALL showed well-organized, dense collagenous tissue fibers with elongated fibroblasts (mean, 1631 fibroblasts/mm2) and a predominance of type I collagen. Conclusion: The ALL is present during fetal development, with anatomic and histological features similar to those of the adult ALL. Clinical Relevance: The findings of this study help to better understand the ALL’s anatomy and histology from the fetal period to adulthood. The study presents the existence of the ALL since fetal development, emphasizes the characterization of the ALL, and brings important information to future pediatric ALL lesion studies.