Effect of tibial plateau fracture on lubrication function and composition of synovial fluid.

Background: Intra-articular fractures may hasten posttraumatic arthritis in patients who are typically too active and too young for joint replacement. Current orthopaedic treatment principles, including recreating anatomic alignment and establishing articular congruity, have not eliminated posttraumatic arthritis. Additional biomechanical and biological factors may contribute to the development of arthritis.

Effects of equine joint injury on boundary lubrication of articular cartilage by synovial fluid: role of hyaluronan.

Objective: To compare equine synovial fluid (SF) from injured and control joints for cartilage boundary lubrication function; concentrations of the putative boundary lubricant molecules hyaluronan (HA), proteoglycan 4 (PRG4), and surface-active phospholipids (SAPLs); relationships between lubrication function and composition; and lubrication restoration by addition of HA.

Methods: Equine SF from normal joints, joints with acute injury, and joints with chronic injury were analyzed for boundary lubrication of normal articular cartilage (kinetic friction coefficient [μ(kinetic) ]). Equine SF samples were analyzed for HA, PRG4, and SAPL concentrations and HA molecular weight distribution.

Cartilage shear dynamics during tibio-femoral articulation: effect of acute joint injury and tribosupplementation on synovial fluid lubrication.

Objective: To determine the effects of acute injury and tribosupplementation by hyaluronan (HA) on synovial fluid (SF) modulation of cartilage shear during tibio-femoral articulation.

Methods: Human osteochondral blocks from the lateral femoral condyle (LFC) and tibial plateau (LTP) were apposed, compressed 13%, and subjected to sliding under video microscopy. Tests were conducted with equine SF from normal joints (NL-SF), SF from acutely injured joints (AI-SF), and AI-SF to which HA was added (AI-SF+HA).

Wear-lines and split-lines of human patellar cartilage: relation to tensile biomechanical properties.

Background: Articular cartilage undergoes age-associated degeneration, resulting in both structural and functional biomechanical changes. At early stages of degeneration, wear-lines develop in the general direction of joint movement. With aging, cartilage exhibits a decrease in tensile modulus.