Injuries to the anterolateral ligament are observed more frequently compared to lesions to the deep iliotibial tract (Kaplan fibers) in anterior cruciate ligamant deficient knees using magnetic resonance imaging

Purpose To determine the accuracy of detection, injury rate and inter- and intrarater reproducibility in visualizing lesions to the anterolateral ligament (ALL) and the deep portion of the iliotibial tract (dITT) in anterior cruciate ligament (ACL) deficient knees. Methods Ninety-one consecutive patients, out of those 25 children (age 14.3 ± 3.5 years), with diagnosed ACL tears were included. Two musculoskeletal radiologists retrospectively reviewed MRI data focusing on accuracy of detection and potential injuries to the ALL or dITT. Lesion were diagnosed in case of discontinued fibers in combination with intra- or peri-ligamentous edema and graded as intact, partial or complete tears. Cohen’s Kappa and 95% confidence intervals (95% CI) were determined for inter- and intrarater reliability measures. Results The ALL and dITT were visible in 52 (78.8%) and 56 (84.8%) of adult-and 25 (100%) and 19 (76.0%) of pediatric patients, respectively. The ALL was injured in 45 (58.5%; partial: 36.4%, compleate: 22.1%) patients. Partial and comleate tears, where visualized in 21 (40.4%) and 16 (30.8%) adult- and seven (28.0%) and one (4%) peditric patients. A total of 16 (21.3%; partial: 13.3%, compleate: 8.0%) dITT injuries were identified. Partal and complete lesions were seen in seven (12.5%) and five (8.9%) adult- and three (15.8%) and one (5.3%) pediatric patients. Combined injuries were visualized in nine (12.7%) patients. Inter-observer (0.91–0.95) and intra-observer (0.93–0.95) reproducibility was high. Conclusion In ACL injured knees, tears of the ALL are observed more frequently compared to lesions to the deep iliotibial tract. Combined injuries of both structures are rare. Clinically, the preoperative visualization of potentially injured structures of the anterolateral knee is crucial and is important for a more personalized preoperative planning and tailored anatomical reconstruction. The clinical implication of injuries to the anterolateral complex of the knee needs further investigation. Level of evidence II.

Predictive Value of the Magnetic Resonance Imaging–Based Coronal Lateral Collateral Ligament Sign on Adolescent Anterior Cruciate Ligament Reconstruction Graft Failure

Background: The coronal lateral collateral ligament (LCL) sign is the presence of the full length of the LCL visualized on a single coronal magnetic resonance imaging (MRI) slice at the posterolateral corner of the knee. The coronal LCL sign has been shown to be associated with elevated measures of anterior tibial translation and internal rotation in the setting of anterior cruciate ligament (ACL) tear. Hypothesis: The coronal LCL sign (with greater anterior translation, internal rotation, and posterior slope of the tibia) will indicate a greater risk for graft failure after ACL reconstructive surgery. Study Design: Cohort study; Level of evidence, 3. Methods: Retrospective review was performed of adolescent patients with ACL reconstruction: a cohort without graft failure and a cohort with graft failure. MRI was utilized to measure tibial translation and femorotibial rotation and to identify the coronal LCL sign. The posterior tibial slope was measured on lateral radiographs. Patient-reported outcomes were collected. Results: We identified 114 patients with no graft failure and 39 patients with graft failure who met all criteria, with a mean follow-up time of 3.5 years (range, 2-9.4 years). Anterior tibial translation was associated with anterolateral complex injury ( P < .001) but not graft failure ( P = .06). Internal tibial rotation was associated with anterolateral complex injury ( P < .001) and graft failure ( P = .042). Posterior tibial slope was associated with graft failure ( P = .044). The coronal LCL sign was associated with anterolateral complex injury ( P < .001) and graft failure ( P = .013), with an odds ratio of 4.3 for graft failure (95% CI, 1.6-11.6; P = .003). Subjective patient-reported outcomes and return to previous level of sport were not associated with failure. Comparison of MRI before and after ACL reconstruction in the graft failure cohort demonstrated a reduced value in internal rotation ( P = .003) but no change in coronal LCL sign ( P = .922). Conclusion: Our study demonstrates that tibial internal rotation and posterior slope are independent predictors of ACL graft failure in adolescents. Although the value of internal rotation could be improved with ACL reconstruction, the presence of the coronal LCL sign persisted over time and was predictive of graft rupture (without the need to make measurements or memorize values of significant risk). Together, these factors indicate that greater initial knee deformity after initial ACL tear predicts greater risk for future graft failure.

Research on the Anterolateral Ligament of the Knee: An Evaluation of PubMed Articles From 2010 to 2019

Background: The anterolateral ligament (ALL) of the knee remains a topic of interest. All aspects of the ligament, including its anatomy, biomechanics, imaging, and clinical importance, are areas for research among knee surgeons. Purpose: To evaluate the trends in research on the ALL of the knee, as indicated by studies indexed in PubMed from 2010 to 2019. Study Design: Cross-sectional study. Methods: We searched PubMed for article titles from January 1, 2010, to December 31, 2019, that included the term “anterolateral ligament.” The initial search was performed with the terms “anterolateral ligament AND knee” and “anterolateral ligament NOT knee.” Next, we performed a search using “anterolateral complex OR anterolateral reconstruction OR lateral extra-articular tenodesis” to avoid missing any studies. A bibliometric evaluation was performed for the search results, and we noted the characteristics of the most cited articles in PubMed. Results: Published studies on the ALL peaked in 2017, with 56 studies, and then declined from 2017 to 2019. The 3 leading journals with articles on the ALL were Arthroscopy; Knee Surgery, Sports Traumatology, Arthroscopy; and The American Journal of Sports Medicine. Cadaveric anatomic, cadaveric biomechanical, and clinical imaging studies of the ALL were the most common types of studies published from 2010 to 2019. Clinical studies on the ALL consisted of 18 articles, with the majority displaying a low level of evidence. Conclusion: Cadaveric anatomic/histological, cadaveric biomechanical, and clinical imaging studies of the ALL were the most commonly published studies from 2010 to 2019. More clinical outcome studies with a high level of evidence are needed to increase the supporting data for the future practice of ALL reconstruction.

PEDIATRIC REFERENCE ANATOMY FOR ANTEROLATERAL LIGAMENT RECONSTRUCTION– A CADAVERIC STUDY

Background: The anatomy of the anterolateral ligament (ALL) has been controversial, with modern studies varying in their description of the precise origin and insertion, as well as relation to surrounding structures on the lateral femur and anterolateral tibia Regardless of such controversy, principles of reconstruction, even non-anatomic, require a clear understanding of the referenced anatomy and surrounding structures. Due to high rates of primary and recurrent ACL tears in pediatric/adolescent patients, the use of ALL reconstruction is increasing in these groups. No pediatric cadaveric study to date has clearly identified the locations of the known surrounding structures of the anterolateral ligamentous complex. Purpose: The purpose of this study was to quantitatively assess the anatomy of the pediatric lateral collateral ligament (LCL) origin, the popliteus origin, and in the tibial insertion of the iliotibioband (ITB). Methods: Nine pediatric cadaveric knee specimens were dissected to identify the ligamentous femoral origin of the LCL, popliteus, and tibial insertion of the ITB.. Marking pins were used to localize the central footprint of these structures, followed by CT Scans. Results: LCL & Popliteus: On the femur, the popliteus was consistently found deep to the LCL and inserted both distally and anteriorly to the LCL a mean distance of 4.6 mm (range 1.9 to 7.6 mm; std dev 2.0). The LCL measured a mean of 12.5 mm to the joint line while the popliteus measured a mean of 8.2 mm from the joint line. Both the LCL and popliteus were consistently distal to the physis. The LCL was a mean distance of 4.4 mm (range 1.0 - 9.5 ) and the popliteus was a mean distance of 8.2 (range 1.7 – 12.5), respectively. ITB insertion: The ITB insertion at Gerdy’s tubercle had an average footprint measuring 28.2 mm2 (range 10.3-58.4), and the ITB center was found proximal to the physis in 6 specimens and distal in 3 specimens. Mean distance from the footprint center to the physis was 1.6 mm proximal (range 7.1 mm proximal to 2.2 mm distal). Conclusion: This study provides quantitative anatomy to structures on the lateral femur and anterolateral tibia, commonly referenced in descriptions of the ALL and lateral extraarticular reconstruction techniques. Knowledge of these structures will define the anterolateral complex and guide extra-articular procedures that provide extraarticular anterolateral rotatory stabilization in the pediatric patients. [Figure: see text][Figure: see text]