Mediolateral Differences of Proteoglycans Distribution at the ACL Tibial Footprint: Experimental Study of 16 Cadaveric Knees

Abstract

This study aimed to identify the staining pattern of ACL attachment blended with cartilage of the medial tibial plateau at the tibial insertion and histologically characterize the tibial footprint. Sixteen fresh frozen cadaveric knees (mean age: 52.0 ± 6.2 years) were used for this study. The specimens were bisected in the coronal plane, in accordance with the fiber orientation of the ACL tibial attachment. Adjacent sections were then stained with hematoxylin and eosin (H&E) to observe the morphology of the ACL insertion and with fast green and Safranin-O protocols to evaluate for collagen and proteoglycans (PG). The insertion area on the tibial footprint was divided into five zones in the medial to lateral direction, which was determined by division of the section from most prominent medial tibial spine to most lateral margin of ACL attachment. Then rectangular area with a vertical length that is twice the width of respective five zones was set. Stained areas of all images were quantified positively by using ImageJ software, and the value for staining area measured was defined in percentage by multiplying whole image area by 100. The mean proportion of Safranin-O staining is significantly greater nearer to the medial tibial spine (59% in zone 1, 32% in zone 2, 13% in zone 3, 13% in zone 4, and 4% in zone 5, P < 0.001). The medial section of the tibial insertion area grew in size and increased in PG staining with more densely organized collagen arrangement with more fibrocartilage cells. The ACL tibial insertion showed a medially eccentric staining pattern by histological evaluation of the ACL attachment to cartilage. Our histological results of the eccentric biomaterial property in the medial tibial spine of ACL insertion area can be considered in making a more functional anatomic tibial tunnel placement.

IL-1β receptor antagonist (IL-1Ra) combined with autophagy inducer (TAT-Beclin1) is an effective alternative for attenuating extracellular matrix degradation in rat and human osteoarthritis chondrocytes

“…Dark brown cells or area were considered to be positive. The positive chondrocytes were counted semi-automated using Image-Pro Plus 6.0 Software, and area was measured using ImageJ Software, followed by analysis with GraphPad Prism version 5 [15, 17, 29, 30].…”

Direct Perfusion Improves Redifferentiation of Human Chondrocytes in Fibrin Hydrogel with the Deposition of Cartilage Pericellular Matrix

“…Samples were imaged with the Axioscan digital slide scanner (Carl Zeiss microscopy, GmbH, Marly Le Roi, France) and analyzed with ZEN 2 (blue edition) software (Carl Zeiss microscopy, GmbH). For safranin-O positive surface area measurements, Tagged Image File Format (TIFF) images were segmented in ImageJ software (version 1.15w, National Institutes of Health) with the Color Threshold plugin [28]. Safranin-O positive areas were isolated by setting Thresholding method to Default, Threshold color to black and white (B&W), Color space to HSB (Hue: 229/255, Saturation: 35/255, Brightness: 0/255) and Dark Background was not selected.…”

Histological Structure of Anterior Cruciate Ligament - Review

“…The medial portion of the tibial insertion area showed the increased staining of PG, with more densely organized collagen arrangement and more fibrocartilage cells under high magnification. [19] Femoral insertion of ACL The histology of ACL femoral origin showed areas of less dense connective tissue among the transitional zone of ligament and cartilage. Two types of insertion of the fibres of the ACL at their femoral attachment were described by Iwahashi et al a 'direct type' with characteristic zonal architecture, allowing for the gradual dissipation of forces, and an 'indirect type' in that the ligament is inserted into bone by collagen fibres without a transitional zone.…”