A Novel Method for Calculating the Frictional Properties of Articular Cartilage Using a Material Testing Machine

Abstract

Osteoarthritis (OA) is a common degenerative joint disease which causes chronic pain, joint destruction, disability, depression, and social in patients. Many researchers have studied the coefficient of friction of articular cartilage (AC) using a variety of methods, especially with the tribology method. Functional biotribology is a useful way to better understand how and why cartilage becomes osteoarthritis. In this study, a novel biomechanical measurement system was built to determine the friction of a sheep joint performing loaded torsional oscillations between the joint surfaces. A surgical induced OA model was used, which was better to control the size, the depth, and the position of the defect.Four different defect groups were designed for this experiment: no defect group, 16mm 2 defect group, 32 mm 2 defect group, and total defect group. The OA model joints were investigated in an oscillating torsion experiment applied by a material testing machine with 12 successive loading cycles in axial direction. Each sample was tested in four different axial loading conditions: 100N, 200N, 450N and 900N axial forces. This the flow chart of the experiment, there are four defect conditions for one joint. The OA model joints were investigated in an oscillating torsion experiment applied by a material testing machine with 12 successive loading cycles in axial direction. Because this was not a simple model for kinetic friction between plane surfaces moving linearly with respect to each other, the frictional energy was used to observe the friction properties of the joint not the frictional coefficient. From the result we could see that the frictional energy showed significant difference in the different defect groups. A strong correlation was showed between different defect groups and the frictional energy. When the size of the defect became bigger, more frictional energy was needed to rotate the joint. Furthermore in one defect group, the frictional energy showed significant difference in different loading conditions, and the friction energy and the loading force also presented a linear correlation. In sum, this novel tribology system was established to estimate the friction of joints, and it was certified to be a useful method to measure the tribology properties of joint, especially the joint of big animal. Thought this system the influence of the defect and the loading force of the joint was presented. With this system a lot of tribology works can be done easily, like cartilage-on-glass, rubber-on-glass, cartilage-on-cartilage, cartilage-on-implant, cartilage with different lubrication. Future works should aim to determine the cartilage friction properties with different lubrications, which are important to synovial joints.

Arthrose ist eine häufig vorkommende und funktionseinschränkende Gelenkerkrankung, welche chronische Schmerzen, Gelenkzerstörung, Arbeitsunfähigkeit und Depressionen auslösen und zur sozialen Isolierung führen kann. In Synovialgelenken, wie dem Kniegelenk, wirkt sich eine beginnende Arthrose durch einen graduellen Abrieb des Gelenkknorpels aus. In vielen extremen Fällen, ist der Gelenkknorpel vollständig abgerieben, mit dem Resultat, dass Knochen auf Knochen reibt. Viele Forscher haben den Reibungskoeffizienten am Gelenkknorpel mit verschiedenen Methoden untersucht, vor allem mit Methoden der Tribologie. In der Biotribologie werden hauptsächlich Reibung, Schmierung und Abnutzung analysiert.