2017 ISAKOS Biennial Congress ePoster #1623


Anterolateral Capsular Complex Exploration in the Human Fetal Knee

Soheil Sabzevari, MD, Pittsburgh, PA UNITED STATES
Amir Ata Rahnemai-Azar, MD, Pittsburgh, PA UNITED STATES
Márcio Bottene Villa Albers, MD, Pittsburgh, PA UNITED STATES
Monica A. Linde, MS, RN, Pittsburgh, PA UNITED STATES
Patrick J. Smolinski, PhD, Pittsburgh, PA UNITED STATES
Freddie H. Fu, MD, Pittsburgh, PA UNITED STATES

Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, UNITED STATES

FDA Status Not Applicable


This study evaluated the anterolateral capsular complex of the fetal knee and the results indicate that the presence of a distinct ligamentous structure in the anterolateral capsular complex is not supported from a developmental aspect.



There is currently disagreement with regard to the presence of a distinct ligament in the anterolateral capsular complex of the knee and its role in the pivot shift mechanism and rotatory laxity of the knee [1,2]. The purpose of this study was to explore the anterolateral capsular complex of the fetal knee to determine whether there exists a distinct ligamentous structure running between lateral femoral condyle areas to anterolateral side of the proximal tibia.


Prior approval was granted by our Institutional Review Board for the use of fetal knee specimens procured from our institution’s tissue bank. Twenty-one unpaired, fresh fetal lower limbs, gestational ages between 18 to 22 weeks were examined. Two experienced orthopedic surgeons performed the anatomical dissection using loupes (magnification: 3.5X). The knee joint was carefully dissected to explore all structures, but attention was focused on the anterolateral and lateral structures of the knee. First, the extra-articular structures were examined and the iliotibial band was carefully separated from underlying structures. Manual loading (internal/external and varus/valgus) was applied, while the anterolateral capsule was examined for the presence of any ligamentous structures. Using a Macroscope at 20x, the intra-articular structures were studied.


The most important finding of this study was the absence of a distinct capsular or extra-capsular ligamentous structure in the anterolateral capsular complex area after the removal of the iliotibial band in any of the specimens. The presence of the lateral collateral ligament, a distal attachment of biceps femoris, the entire lateral capsule, the iliotibial band, and the popliteus tendon in the anterolateral and lateral area of the knee was confirmed in all the samples. Intra-articular dissection revealed the anterior and posterior cruciate ligaments, the meniscofemoral ligament, the menisci and a synovium.


It is important to know whether there is a ligament in the anterolateral capsular complex of the knee, its role in knee rotational stability and if there are indications for surgery. The presence of this ligament and its anatomical properties in fetus has not been substantiated.

Acknowledgements: This project used the UPCI Health Sciences Tissue Bank that is supported in part by award P30CA047904.

References: 1) Nitri M et al. An In Vitro Robotic Assessment of the Anterolateral Ligament, Part 2: Anterolateral Ligament Reconstruction Combined With Anterior Cruciate Ligament Reconstruction. Am J Sports Med. 2016;44(3):593-601. 2) Wroble RR et al. The role of the lateral extraarticular restraints in the anterior cruciate ligament-deficient knee. Am J Sports Med. 1993;21(2):257-262; discussion 263.