The Joints and Synovial Fluid

Abstract

This chapter provides an overview of the general pathology of the peripheral joints. Synovial joints are functional interfaces; they lie at the line of demarcation between hydrostat and rigid framework and are so formed that their physiological and pathological behavior is dominated by either characteristic or by a combination of the two. Disorders of synovial joints are disturbances of the cells of non-mineralized connective tissue, of mineralized tissue, or of both. In osteoarthrosis (OA), the marginal osteophytes may be predominantly hyaline cartilage, fibrocartilage, compact or cancellous bone, and bone marrow. The bone of OA is often hyperemic. Raised bone metabolism prevails; excess reactive bone deposition and excess bone resorption are prominent, and trabecular microfracture is associated with these changes. Subchondral bone cysts develop inconstantly. They may reach a diameter of 2.0 cm; there is a dense, bony wall, a fibrous lining, and a content of loose myxoid material which may be fluid. Osteophytic outgrowths of bone develop both at the chondro–synovio–osseous margin of an affected joint and near attachments of the capsule and of the articular ligaments to bone. Many systemic and local conditions may lead to secondary OA. Among these are mucopolysaccharidoses; metabolic bone disease; some forms of aseptic bone necrosis; rheumatoid, infective, and traumatic arthritis; and hemophilia.