A preliminary ferrographic survey of the wear particles in human synovial fluid

Abstract

The technique of ferrography has been applied to the analysis of wear particles in human synovial fluid aspirates. A number of discrete, identifiable classes of wear particles were found, including particles indicative of cutting wear and rubbing wear. The spectrum of particles varied among different groups of patients, suggesting an eventual diagnostic use for this method.No reliable method exists for the early diagnosis of degenerative arthritis. Present diagnoses rely upon radiographic or clinical data which are insufficiently sensitive to detect those early changes presignifying this condition. Osteoarthritis involves progressive erosion of the articular cartilage, eventually exposing and abrading the subchondral bone. Tissue is probably destroyed by a combination of mechanical deterioration and enzymic attack (1).Wear is a process affecting all moving surfaces, including those found in joints. Wear particles are the products of wear. In their size, shape, and composition resides the history of their production. Ferrography has proved itself to be a way of interpreting this history for wear particles that arise in machines (2). It is based on the magnetic separation of small, ferromagnetic, metal- lic wear particles which are shed from the surfaces of various components of an engine into the lubricating oil. As the machine shifts from one normal wear mode into a different normal or abnormal wear mode, the spectrum of wear particles alters accordingly. This change is detected by ferrography. As well as providing an early warning system for future, potential engine failure, ferrographic analysis of wear particles has aided basic research into the fundamentals of tribology (3).Application of ferrography to the study of wear particles in human articulating joints might, by a similar token, be expected to provide a sensitive, non-invasive diagnostic technique for the detection of early stages of degenerative joint disease. It also has the potential to shed new light on the etiology, pathogenicity, biomechanics, and tribology of osteoarthritis and other arthritides.Ferrography has already been applied to the analysis of wear in artificial joint replacements (4,5). These studies confirmed that the technique can monitor wear in arthroplastic joint implants. In these investigations, minute fragments of metal from the replacement femoral head rendered the wear particles sufficiently magnetic for ferrographic analysis without further treatment. For biological joints, with their diamagnetic constituents, the wear particles need to be artificially rendered susceptible to a magnetic field.Previous work has led to the development of a method for magnetizing the wear particles found in synovial fluid and analyzing them ferrographically (6). Here we report our initial findings in applying this method to human synovial fluid aspirates and saline washings of diarthrodial joints. In this study, we were particularly anxious to verify the premises that biological wear particles do indeed occur in synovial fluid and

Toward understanding the role of cartilage particulates in synovial inflammation

“…Increased cartilage wear, leading to formation of loose particles in the joint space, has been linked to aging, overuse and obesity 2 , often leading to osteoarthritis (OA). Several studies have investigated using synovial fluid aspirates to diagnose OA by characterizing cartilage wear particles in the synovial joint 3–5 . Clinically, it has been observed that cartilage and bone debris are bound to the surface or embedded deep within the synovial membrane of patients suffering from capsular synovial hyperplasia and metaplasia 6 .…”

Immunohistologic demonstration of type ii collagen in synovial fluid phagocytes of osteoarthritis and rheumatoid arthritis patients

“…Kitridou et a1 demonstrated collagen in 10 of 18 fluids from OA joints and in 1 of 5 fluids from RA joints, using electron microscopy and hydroxyproline assay after acid hydrolysis (15). Other investigators have demonstrated a correlation between articular lesions detected by arthroscopy and identification of cartilage fragments in SF, and have advocated the potential diagnostic use of such analyses (16,17). Cheung et al, using sodium dodecyl sulfatepolyacrylamide gel electrophoresis and spectrophotometric scanning, demonstrated collagen in 12 of 17 pellets prepared from fluid aspirates from 17 knee joints of patients with various forms of arthritis (18).…”

Wear in human knees

“…Particles need to have a positive volumetric magnetic susceptibility of the order of 50 Â 10 À 6 or more to be deposited in ferrography. This approach was applied to prepare wear particles found in synovial fluid to study wear in human knee joints [4,[83][84][85][86][87][88]. Wear particles found in human knee joints do not have positive magnetic susceptibility.…”