From this study, the ALL is an independent structure in the anterolateral compartment of the knee and may serve a proprioceptive role in knee mechanics.

Background: Anatomic anterolateral ligament (ALL) reconstruction has been proposed to assist anterior cruciate ligament (ACL) reconstruction in controlling anterolateral rotational laxity of the knee. However, the biomechanical effects have not been reported. Purpose: (1) To investigate the effect of ALL transection on rotational knee kinematics and (2) to determine the effect on knee biomechanics of ALL reconstruction procedures compared with lateral extra-articular tenodesis (LET). Study Design: Controlled laboratory study. Methods: A total of 12 cadaveric knee specimens were tested in the following sequence: (1) ACLintact, (2) anteromedial bundle of ACL sectioned (ACLamb), (3) complete ACL sectioned (ACLfull), (4) ALL sectioned (ALLsec), (5) anatomic ALL reconstruction (ALLanat), and (6) LET. Biomechanical anterior drawer and Lachman tests were performed in which a 90-N load was applied to the posterior tibia, and anterior translation was measured. A combined load to simulate the early phase of the pivot-shift test was executed in which a 5-N·m internal rotation moment was applied to a fully extended knee; anterior translation and internal rotation were measured. Results: Anterior translation increased across conditions for the biomechanical tests. Internal rotation during the simulated early-phase pivot-shift test was significantly different between ACLfull and ALLsec. Anatomic ALL reconstruction did not significantly reduce internal rotation or anterior translation during the simulated early-phase pivot-shift test. After LET, a significant decrease in anterior translation was found. There was no evidence of overconstraint of the knee with either anatomic ALL reconstruction or LET. Conclusion:The ALL demonstrated a role in controlling anterolateral laxity. LET had a composite effect in governing both anterior and rotational laxity. Anatomic ALL reconstruction did not reduce anterolateral rotational laxity. Clinical Relevance: Profiling the biomechanical characteristics of anterolateral reconstruction is integral to understanding the implications and potential benefit of such an additional procedure to ACL reconstruction.

Background:Anatomic anterolateral ligament (ALL) reconstruction has been proposed to assist anterior cruciate ligament (ACL) reconstruction in controlling anterolateral rotational laxity of the knee. However, the biomechanical effects have not been reported.Purpose:(1) To investigate the effect of ALL transection on rotational knee kinematics and (2) to determine the effect on knee biomechanics of ALL reconstruction procedures compared with lateral extra-articular tenodesis (LET).Study Design:Controlled laboratory study.Methods:A total of 12 cadaveric knee specimens were tested in the following sequence: (1) ACLintact, (2) anteromedial bundle of ACL sectioned (ACLamb), (3) complete ACL sectioned (ACLfull), (4) ALL sectioned (ALLsec), (5) anatomic ALL reconstruction (ALLanat), and (6) LET. Biomechanical anterior drawer and Lachman tests were performed in which a 90-N load was applied to the posterior tibia, and anterior translation was measured. A combined load to simulate the early phase of the pivot-shift test was executed in which a 5-N·m internal rotation moment was applied to a fully extended knee; anterior translation and internal rotation were measured.Results:Anterior translation increased across conditions for the biomechanical tests. Internal rotation during the simulated early-phase pivot-shift test was significantly different between ACLfull and ALLsec. Anatomic ALL reconstruction did not significantly reduce internal rotation or anterior translation during the simulated early-phase pivot-shift test. After LET, a significant decrease in anterior translation was found. There was no evidence of over-constraint of the knee with either anatomic ALL reconstruction or LET.Conclusion:The ALL demonstrated a role in controlling anterolateral laxity. LET had a composite effect in governing both anterior and rotational laxity. Anatomic ALL reconstruction did not reduce anterolateral rotational laxity. Clinical Relevance: Profiling the biomechanical characteristics of anterolateral reconstruction is integral to understanding the implications and potential benefit of such an additional procedure to ACL reconstruction.

Using direct lateral fluoroscopy, radiographic landmarks of the ALL origin and insertion have been described.

No abstract

These results suggest that time zero MAT performs in a similar manner to the native meniscus. Optimizing MAT strain behavior may lead to potential improvements in its chondroprotective effect.

Purpose Meniscal graft extrusion is a concern following meniscal allograft transplantation (MAT). MAT surgical techniques continue to evolve in an effort to reduce extrusion; however, improvements remain difficult to measure in vivo. A novel MRIcompatible in vitro loading device capable of applying physiologically relevant loads has been developed, allowing for the measurement of extrusion under a variety of controllable conditions. The objective of this study was to compare maximal medial MAT extrusion (1) with and (2) without an additional peripheral third point of fixation on the tibial plateau. Methods Twelve human cadaveric knees underwent medial MAT, utilizing soft tissue anterior and posterior root fixation via transosseous suture, with a third transosseous suture tied over a button providing peripheral fixation on the tibial plateau. The joint was positioned at 5 degrees of flexion and loaded to 1 × body weight (647.7 ± 159.0 N) during MR image acquisition, with and without peripheral fixation. The joint was then positioned at 30 degrees of flexion and the process was repeated. Maximal coronal extrusion was measured. Results An increase in maximal coronal meniscal extrusion was noted between the unloaded and loaded states. At 30 degrees of flexion, with the addition of a peripheral fixation point, a statistically significant difference in absolute extrusion (p = 0.02) and relative percent extrusion (p = 0.04) between the unloaded and loaded state was found. The addition of a peripheral fixation suture resulted in an overall mean percent difference of − 2.49% (SD 14.1; 95% CI − 11.95, 6.97; n.s.) in extrusion at 5 degrees of flexion and a mean percent difference of − 0.95% (SD 7.3; 3.71; n.s.) in extrusion at 30 degrees of flexion. These differences were not statistically significant. Conclusion These results suggest that the addition of a peripheral anchor in medial MAT does not reduce the amount of maximal coronal extrusion and, therefore, may not confer any clinical benefit. Surgical techniques utilized to reduce MAT extrusion need further investigation to understand if the added technical difficulty and potential expense is warranted.

For over 140 years, a structure located on the lateral side of the knee has been recognized but poorly understood by surgeons. Most recently termed the Anterolateral Ligament (ALL), it has been described to consistently originate on the lateral femoral condyle and insert onto the tibia posterior to Gerdy’s tubercle. This study aims to characterize the anatomical properties of the ALL utilizing magnetic resonance imaging, cadaveric dissection, and histological/immunohistochemical sectioning of fresh‐frozen human cadaveric knees. Preliminary results show that in each of the 7 cadaveric specimens undergoing 3T MRI analysis, the ALL can be identified as a distinct, densely arranged structure. The ALL was then clearly visualized in all 9 cadaveric dissections, showing variable origin on the lateral femoral condyle and consistent insertion on the tibia. H&E histological sectioning of 2 cadaveric specimens also indicates that the ALL is ligamentous in nature, revealing a dense, regular network of collagenous tissue. In 1 specimen, immunohistochemistry specific to neurofilament proteins found in axons show peripheral nervous innervation of the ALL, indicating ligamentous tissue. These results show that the ALL can be confidently identified in a multitude of different modalities, providing clear evidence that the ALL is a distinct ligament of the lateral knee.