A Quantitative Study of the Microstructure and Biochemistry of the Medial Meniscal Horn Attachments

Abstract

Abstract-Little quantitative data is available on the structure of meniscal attachments. Therefore, as an aid to designing meniscal replacements as well as a possible explanation for mechanical behavior, this study was designed to further the knowledge of the microstructure and biochemistry of native meniscal attachments. Bovine medial meniscal attachments (the external ligamentous portion as well as the transition zones at the bony insertion) were removed and prepared for microstructural evaluation. After embedding in paraffin, the samples were sliced on a microtome and stained for quantitative analysis. The anterior and posterior insertion sites are known to contain three zones: subchondral bone, calcified fibrocartilage, and uncalcified fibrocartilage. Additionally, others have shown that the anterior insertion site contains a ligamentous zone. The insertion zones were further divided into proximal, middle, and distal zones. The posterior attachment's insertion site had a significantly greater thickness of interdigitations, subchondral bone, uncalcified fibrocartilage, and calcified fibrocartilage zone thickness compared to the anterior attachment insertion. The anterior attachment's insertion had the greatest GAG fraction in each zone when compared to the posterior attachment's insertion. GAG fraction decreased from the meniscus to the subchondral bone. Both GAG fraction and normalized thickness varied within a given zone, decreasing from the distal to proximal regions in both the anterior and posterior attachments' insertion zones. Crimp frequency of the collagen fibrils in the external ligamentous portion of the tissue was homogeneous along the length. The findings from this study agree with previously published material property data on the medial meniscal attachments, and could be used in the future to design methods of attachment for tissue engineered replacement menisci.

Efficacy and safety of adult human bone marrow-derived, cultured, pooled, allogeneic mesenchymal stromal cells (Stempeucel®): preclinical and clinical trial in osteoarthritis of the knee joint

“…The binding intensity of Safranin-O to the sGAG was quantified using imageJ software [25]. The region of interest (ROI) around the cartilage area ( n  = 3 per section) was selected, and the intensity of red (R), green (G), and blue (B) were measured and the proportion of red staining was calculated using the equation r = R/ (R 2  + G 2  + B 2 ) 1/2 where, R is the intensity of red and 'r' refers to the intensity of the red fraction with respect to other primary colors [26]. The sections were graded and quantified by an independent observer blinded to the treatment groups.…”

Medial Meniscus Posterior Root Tear: A Comprehensive Review

“…The meniscus has an important multifunctional role in load transmission, shock absorption, joint stability and lubrication, proprioception, and nutrient supply to maintain overall function of the knee1,2). Of these, the most important function for the prevention of arthritis is the maintenance of hoop tension that allows correct intraarticular load transmission for which the medial meniscus is approximately 90% responsible and the lateral meniscus is approximately 70% responsible3,4).…”

Next generation tissue engineering of orthopedic soft tissue-to-bone interfaces

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