The Role of the Peripheral Passive Rotation Stabilizers of the Knee With Intact Collateral and Cruciate Ligaments: A Biomechanical Study

Abstract

Background:A subset of patients have clinical internal and/or external knee rotational instability despite no apparent injury to the cruciate or collateral ligaments.Purpose/Hypothesis:The purpose of this study was to assess the effect of sequentially cutting the posterolateral, anterolateral, posteromedial, and anteromedial structures of the knee on rotational stability in the setting of intact cruciate and collateral ligaments. It was hypothesized that cutting of the iliotibial band (ITB), anterolateral ligament and lateral capsule (ALL/LC), posterior oblique ligament (POL), and posteromedial capsule (PMC) would significantly increase internal rotation, while sectioning of the anteromedial capsule (AMC) and the popliteus tendon and popliteofibular ligament (PLT/PFL) would lead to a significant increase in external knee rotation.Study Design:Controlled laboratory study.Methods:Ten pairs (N = 20) of cadaveric knees were assigned to 2 sequential cutting groups (group 1: posterolateral-to-posteromedial [PL → PM] and group 2: posteromedial-to-posterolateral [PM → PL]). Specimens were subjected to applied 5-N·m internal and external rotation torques at knee flexion angles of 0°, 30°, 60°, and 90° while intact and after each cut state. Rotational changes were measured and compared with the intact and previous cut states.Results:Sectioning of the ITB significantly increased internal rotation at 60° and 90° by 5.4° and 6.2° in group 1 (PL → PM) and 3.5° and 3.8° in group 2 (PM → PL). PLT/PFL complex sectioning significantly increased external rotation at 60° and 90° by 2.7° and 2.9° in group 1 (PL → PM). At 60° and 90° in group 2 (PM → PL), ALL/LC sectioning produced significant increases in internal rotation of 3.1° and 3.5°, respectively. In group 2 (PM → PL), POL sectioning produced a significant increase in internal rotation of 2.0° at 0°. AMC sectioning significantly increased external rotation at 30° to 90° of flexion with a magnitude of change of <1° in both groups 1 (PL → PM) and 2 (PM → PL).Conclusion:Collectively, the anterolateral corner structures provided primary internal rotation control of the knee from 60° to 90° of knee flexion in knees with intact cruciate and collateral ligaments. The ITB was the most significant primary stabilizer of internal rotation. The POL had a primary role for internal rotational stability at full extension. The PLT/PFL complex was a primary stabilizer for external rotation of the knee at 60° and 90°.Clinical Relevance:This study delineates the primary and secondary roles of the ITB, ALL/LC, POL, and PLT/PFL to rotatory stability of the knee and provides new information to understand knee rotational instabilities.

Anterolateral Knee Extra-articular Stabilizers: A Robotic Sectioning Study of the Anterolateral Ligament and Distal Iliotibial Band Kaplan Fibers

“…Other studies have also indicated the importance of the ITB in restraining internal rotation. 11,13,28 A recent study by Vap et al 27 demonstrated the relevant roles of the distal ITB and the ALL–lateral capsule complex. When the distal ITB was sectioned before the ALL–lateral capsule complex, the observed changes were greater than those observed when the ALL–lateral capsule complex was sectioned before the distal ITB.…”

Anterolateral Ligament Reconstruction Protects the Repaired Medial Meniscus: A Comparative Study of 383 Anterior Cruciate Ligament Reconstructions From the SANTI Study Group With a Minimum Follow-up of 2 Years

“…5,8,12,36,44 Sectioning of the ALL in biomechanical cadaveric studies resulted in greater rotational laxity in both the ACL-deficient knee 43 and the ACL-intact knee. 51 Augmentation of ACLR with an extra-articular tenodesis was shown to decrease rotational laxity and residual pivot shift. 12,13 Recently published clinical results demonstrated reduced failure of combined ACLR and ALLR as compared with isolated ACLR, which may be attributed to biomechanical load-sharing properties of the ALL graft.…”

Evolving evidence in the treatment of primary and recurrent posterior cruciate ligament injuries, part 1: anatomy, biomechanics and diagnostics

“…In the authors’ (PWW, VM) approach, the posterior drawer test is performed in internal, neutral, and external rotation of the tibia to assess additional injuries of the peripheral capsuloligamentous structures since biomechanical studies have shown that the structures of the PMC and PLC are secondary restraints against internal and external tibial torque, respectively [ 30 , 35 , 54 , 58 , 70 , 75 ]. Furthermore, all PCL injuries are classified according to the classifications proposed by the American Medical Association [ 60 ], Hughston and colleagues [ 27 , 28 ], and Harner et al [ 20 ].…”