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.