Osteoarthritic meniscal entheses exhibit altered collagen fiber orientation.

Purpose/aim: The knee menisci are vital for maintaining the stability of the joint, allowing for force distribution, and protecting the underlying articular cartilage during loading. Each meniscus is attached to the underlying bone via two ligamentous entheses composed of collagen fibers that are continuous throughout all four zones of the attachment: ligament, uncalcified fibrocartilage, calcified fibrocartilage, and subchondral bone. The collagen fibers of the meniscal entheses are important for proper functionality of the entheses, particularly in preventing meniscal extrusion which is a common hallmark of osteoarthritis.

Improving the Intercellular Uptake and Osteogenic Potency of Calcium Phosphate via Nanocomplexation with the RALA Peptide.

Calcium phosphate-base materials (e.g., alpha tri-calcium phosphate (α-TCP)) have been shown to promote osteogenic differentiation of stem/progenitor cells, enhance osteoblast osteogenic activity and mediate in vivo bone tissue formation.

A Hydrogel Meniscal Replacement: Knee Joint Pressure and Distribution in an Ovine Model Compared to Native Tissue.

Pressure distribution of the native ovine knee meniscus was compared to a medial meniscectomy and three treatment conditions including a suture reattachment of the native tissue, an allograft, and a novel thermoplastic elastomer hydrogel (TPE) construct. The objective of this study was to assess the efficacy of a novel TPE hydrogel construct at restoring joint pressure and distribution. Limbs were loaded in uniaxial compression at 45°, 60°, and 75° flexion and from 0 to 181 kg.

Mechanical Properties and Cell Compatibility of Agarose Hydrogels Containing Proteoglycan Mimetic Graft Copolymers.

Proteoglycans have vital biochemical and biomechanical functions. Their proteolytic degradation results in loss of these functions. We have previously reported nonprotein proteoglycan-mimetic graft copolymers that stabilize and deliver growth factors and are not subject to proteases.

Hierarchically Structured Electrospun Scaffolds with Chemically Conjugated Growth Factor for Ligament Tissue Engineering.

The anterior cruciate ligament (ACL) of the knee is vital for proper joint function and is commonly ruptured during sports injuries or car accidents. Due to a lack of intrinsic healing capacity and drawbacks with allografts and autografts, there is a need for a tissue-engineered ACL replacement. Our group has previously used aligned sheets of electrospun polycaprolactone nanofibers to develop solid cylindrical bundles of longitudinally aligned nanofibers.

Mechanical properties and cellular response of novel electrospun nanofibers for ligament tissue engineering: Effects of orientation and geometry.

Electrospun nanofibers are a promising material for ligamentous tissue engineering, however weak mechanical properties of fibers to date have limited their clinical usage. The goal of this work was to modify electrospun nanofibers to create a robust structure that mimics the complex hierarchy of native tendons and ligaments. The scaffolds that were fabricated in this study consisted of either random or aligned nanofibers in flat sheets or rolled nanofiber bundles that mimic the size scale of fascicle units in primarily tensile load bearing soft musculoskeletal tissues.

Assessment of cortical and trabecular bone changes in two models of post-traumatic osteoarthritis.

Subchondral bone is thought to play a significant role in the initiation and progression of the post-traumatic osteoarthritis. The goal of this study was to document changes in tibial and femoral subchondral bone that occur as a result of two lapine models of anterior cruciate ligament injury, a modified ACL transection model and a closed-joint traumatic compressive impact model. Twelve weeks post-injury bones were scanned via micro-computed tomography.