Biotribological and biomechanical changes after experimental haemarthrosis in the rabbit knee

Changes in articular cartilage after haemarthrosis have not been completely elucidated in haemophilic arthropathy. Insights into the pathophysiological mechanisms of blood-induced joint damage mainly derived from histological, inflammatory and biochemical investigations. A structure-function relationship is another reasonable way to determine the joint overall health status. Cartilage, a viscoelastic connective tissue, is at least a biphasic material that should also work under minimal friction. Pendulum friction tester measures the mechanical aspects of joint lubrication and quantifies the biotribological properties of the joint. Indentation test is an in situ method characterizing the biomechanical properties of the cartilage. Gross, biotribological and biomechanical properties were determined in a rabbit model of experimental haemarthrosis. A sample of 1 mL of fresh autologous blood was injected in the left knee of rabbit's joint twice weekly for four consecutive weeks. The right knee and animals in the control group were left untreated. After 8 days, joint perimeter, biotribological and biomechanical tests were performed. In a consistent manner, all data showed detrimental effects of the blood on the overall cartilage function under loading. Non-weight bearing and early blood aspiration seem wise to be considered after haemarthrosis.