The role of the lateral extraarticular restraints in the anterior cruciate ligament-deficient knee

Abstract

We measured the increases in tibiofemoral motion when lateral structures were sectioned in anterior cruciate ligament-deficient knees of 20 unembalmed cadaveric whole lower limbs. Motion was measured with a six degrees-of-freedom electrogoniometer. The lateral structures investigated were the iliotibial band and mid-lateral capsule, lateral collateral ligament, and popliteus tendon and the posterolateral capsule. Cutting the anterolateral structures increased anterior translation and internal rotation, particularly in flexion. Increases in motions were highly variable, reflecting the variation in function in the lateral collateral ligament and posterolateral structures. Cutting the lateral collateral ligament produced small changes in anterior translation and external rotation and larger increases in adduction. Cutting the posterolateral structures produced small increases in external rotation. Large increases in external rotation were found only if the lateral collateral ligament was also sectioned. The posterolateral structures act in concert with the lateral collateral ligament in restraining internal and external rotation. External rotation was affected at all flexion angles; internal rotation was affected mainly in extension. Our results can be used in the diagnosis of complex knee ligament injuries. Findings of increased anterior translation in both flexion and extension and increased internal rotation at 90 degrees of flexion are consistent with combined injury to the anterior cruciate ligament and the anterolateral structures. The anterior cruciate ligament-deficient knee with significant posterolateral compromise (posterolateral structures/lateral collateral ligament) would exhibit larger anterior translation in extension than in flexion, increased adduction, and increased external rotation in both flexion and extension.

Biomechanical Role of Lateral Structures in Controlling Anterolateral Rotatory Laxity: The Iliotibial Tract

“…(13,14) Some authors (14,15) observed an increased IR after isolated sectioning of the ACL, whereas other authors did not find any difference (13,16) compared to the intact state of the knee. Wroble et al (17) found in a biomechanics cadaver study that IR increased significantly after sectioning the anterolateral structures in an ACL-deficient knee at 30° and greater flexion angles.…”

The Biomechanics of the Anterior Cruciate Ligament and Its Reconstruction

“…Ligament strain (Ahmed et al, 1987;Bach & Hull, 1998;Berns et al, 1992;Beynnon et al, 1992;Beynnon et al, 1997;Fleming et al, 2001;Gabriel et al, 2004;Sakane et al, 1997;Takai et al, 1993;Torzilli et al, 1994) or load Markolf et al, 1995) increases with an anterior force on the tibia. When the ACL is cut anterior translation increases (Diermann et al, 2009;Fukubayashi et al, 1982;Hsieh & Walker, 1976;Markolf et al, 1976;Oh et al, 2011;Reuben et al, 1989;Wroble et al, 1993;Yoo et al, 2005;Zantop et al, 2007), or a given translation is resisted by a lesser force (Butler et al, 1980;Li et al, 1999;Lo et al, 2008;. And while the function of the whole ligament is beyond question here, that of the two bands is another matter.…”

Basic biomechanic principles of knee instability

“…Historically, the anterolateral capsule has been described as a secondary stabilizer of anterior translation and rotation of the lateral compartment [14]. This has been well documented in instances of combined injury to the anterior cruciate ligament and the anterolateral structures, where increased anterior translation and increased internal rotation at 90°of flexion has been quantified compared to isolated ACL injuries [48]. Furthermore, the addition of lateral capsule or ALL ligament injury to an isolated ACL injury has increased the magnitude of the reduction during the pivot shift test in cadaveric navigation and robot studies, establishing its role in the control of dynamic rotational laxity [14,49].…”

“…Dissection of the anterolateral capsule or iliotibial band (ITB) or both results in increased rotational movement in ACL-deficient knees, indicating a secondary role of these structures in rotational stability. These results were obtained in cadaveric studies, with the individual use of a navigation system, electrogoniometer and robotic testing system to document objective knee movement [14,48,55,56]. Recently, the ITB has been demonstrated to have large contributions in the restraint of lateral tibial translation and tibial internal rotation [57•].…”