NUMERICAL-ANALYSIS OF WEAR PARTICLES FROM NON-ARTHRITIC AND OSTEOARTHRITIC HUMAN KNEE JOINTS

Wear processes occur in synovial joints and as a result wear particles are produced. Preliminary work has shown that the shape of these part icles might be related to joint diseases. Samples of knee joint synovi al fluid were collected from thirty patients and analysed for wear par ticles. The condition of the patients' joints selected for the study r anged from healthy to severely osteoarthritic. Populations of particle s were extracted from synovial fluid samples by ferrography and analys ed in a scanning electron microscope (SEM). The SEM particle images we re then processed by a computer and analysed numerically. Numerical pa rticle shape descriptors, such as the boundary fractal dimension, shap e factor, convexity and elongation were calculated. A non-parametric M ann-Whitney-Wilcoxon rank test and multiple comparison test performed on the knee joint particle populations demonstrated that there are cle ar differences in the particle shape between these populations, i.e. t hat there is a direct relationship between wear particle shape and joi nt condition. The results obtained indicate that the particle shape ca n be used as an indicator of the synovial joint condition, i.e. in the diagnosis and prognosis of joint diseases. (C) 1997 Elsevier Science S.A.