In Vivo Anterolateral Ligament Length Change in the Healthy Knee During Functional Activities—A Combined Magnetic Resonance and Dual Fluoroscopic Imaging Analysis

Abstract

Purpose To measure the in vivo anterolateral ligament (ALL) length change in healthy knees during step-up and sit-to-stand motions. Methods Eighteen healthy knees were imaged using magnetic resonance (MR) and dual fluoroscopic imaging techniques during a step-up and sit-to-stand motion. The ALL length change was measured, using the shortest 3-D wrapping path, with its femoral attachment located slightly anterior-distal (ALLClaes) or posterior-proximal (ALL-Kennedy) to the fibular collateral ligament (FCL) attachment. The ALL length measured from the extended knee position of the non-weight-bearing MR-scan, was used as a reference to normalize the length change. Results During the step-up motion (~55° flexion to full extension) both the ALL-Claes and ALL-Kennedy showed a significant decrease in length of 21.2% (95% confidence interval 18.0 to 24.4, P<0.001) and 24.3% (20.6 to 28.1, P<0.001) respectively. During the sit-to-stand motion (~90° flexion to full extension), both the ALL-Claes and ALL-Kennedy showed a consistent, significant decrease in length of 35.2% (28.8 to 42.2, P<0.001) and 39.2% (32.4 to 46.0, P<0.001) respectively. From ~90° to 70° of flexion, a decrease in length of approximately 6% was seen; 70° of flexion to full extension resulted in an approximate 30% decrease in length. Conclusion The ALL was found to be a non-isometric structure during the step-up and sit-to-stand motion. The length of the ALL was approximately 35% longer at ~90° of knee flexion when compared to full extension and showed decreasing length at lower flexion angles. Similar ALL length change patterns were found with its femoral attachment located slightly anterior-distal or posterior-proximal to the FCL attachment. Clinical Relevance These data suggest that, if performing anatomic ALL reconstruction, graft fixation may be performed beyond 70° flexion to reduce the chance of lateral compartment overconstraint. Anatomic ALL reconstruction may affect the knee kinematics more in high flexion than at low flexion angles.

Technical considerations in lateral extra-articular reconstruction coupled with anterior cruciate ligament reconstruction: A simulation study evaluating the influence of surgical parameters on control of knee stability

“…In addition, similar to Kernkamp et al (2017), we denoted that LER lengthened during the early degrees of knee flexion and started to shorten at about 35 degrees of knee flexion when the femoral graft was located posteriorly and proximally to the femoral epicondyle and the tibial graft positioned on the gerdys's tubercle or anatomical insertion of the anterolateral ligament ( Supplementary File 2). In addition, previous cadaveric studies (Geeslin et al, 2018;Inderhaug et al, 2017aInderhaug et al, , 2017b pointed out that LER controlled knee rotation and anterior translation.…”

In‐vivo elongation of anterior and posterior cruciate ligament in bi‐cruciate retaining total knee arthroplasty

“…However, cadaveric studies is limited as the in‐vitro testing condition cannot properly simulate in‐vivo physiological knee performances . In this study, the ACL and PCL length measurement under in‐vivo conditions was performed using a previously published technique . The ACL and PCL attachment areas on the BCR TKA and non‐operated knees were first determined at each flexion angle.…”

“…The ACL and PCL attachment areas on the BCR TKA and non‐operated knees were first determined at each flexion angle. An optimization procedure was implemented to find the shortest 3D wrapping path of each bundle of ACL and PCL portion during STS, and the lengths of each portion were determined . Following that, determination of the wrapping length (ɭ) of each bundle of ACL and PCL during STS was performed.…”

Lateral extra-articular reconstruction length changes during weightbearing knee flexion and pivot shift: A simulation study

“…These should be located such that the LER confers physiological knee kinematics, specifically restoration of rotational control and avoidance of overconstraint [10]. The recent literature, including in-vivo and in-vitro studies, has reported a range of different femoral tunnel positions which includes directly proximal to the lateral epicondyle [9-11-12], posteroproximal [13][14] or postero-distal [15]. However, there is increasing consensus that a posteroproximal femoral attachment allows the most favorable behavior, with an LER that is lengthened in knee extension and shortened in flexion [10][11][12][13][14][15].…”

“…The recent literature, including in-vivo and in-vitro studies, has reported a range of different femoral tunnel positions which includes directly proximal to the lateral epicondyle [9-11-12], posteroproximal [13][14] or postero-distal [15]. However, there is increasing consensus that a posteroproximal femoral attachment allows the most favorable behavior, with an LER that is lengthened in knee extension and shortened in flexion [10][11][12][13][14][15]. With respect to the tibial graft insertion, Wieser, Furnstahl, Carrillo, Fucentese and Vlachopoulos [12] reported that, during a weight-bearing squat, the most isometric point was located at 37% of the postero-anterior width of the tibial plateau.…”