Related Experiment Video
Updated: Mar 1, 2026

A Reproducible Cartilage Impact Model to Generate Post-Traumatic Osteoarthritis in the Rabbit
Published on: November 21, 2023
Arthritis associated with apatite crystals
Abstract:
Needle-shaped crystals of 75 to 250 A diameter have been identified by transmission electron microscopy in clumps within synovial fluid mononuclear cell vacuoles in a variety of joint diseases. These crystals, similar to those previously associated with calcific periarthritis, were seen in acute undiagnosed arthritis and in exacerbations of osteoarthritis where they may be inducing a synovitis similar to that seen with urate and pyrophosphate crystals in gout and pseudogout. By light microscopy purple staining cytoplasmic inclusions or extracellular globules can suggest the presence of clumps of these crystals. Apatite clumps can also occasionally appear as small birefringent chunks or rods and thus might mimic urate or calcium pyrophosphate. Ultrastructural appearance, electron probe analysis, and X-ray diffraction pattern were those of apatite. Experimental injection of hydroxyapatite crystals into dog knee joints produces inflammation supporting the potential role for these crystals in joint disease.
Related Concept Videos
Peripheral Artery Disease I: Introduction
Chronic Kidney Disease II: Clinical Manifestations
Urinary Tract Calculi III: Medical Management
Bone Disorders
Bone deposition is also affected by the levels of sex hormones like estrogen and testosterone that promote osteoblast activity and bone matrix synthesis. When the level of these hormones decreases due to aging, it causes a reduction in bone deposition. As a result, bone resorption by osteoclasts...
Chronic Pancreatitis I: Introduction
Pancreatitis is the inflammation of the pancreas, which occurs when the immune system becomes active and causes swelling, pain, and disruptions in organ function. Pancreatitis can manifest as either an acute or chronic condition.
Acute pancreatitis arises suddenly and lasts for a brief duration, while chronic pancreatitis is a long-term affliction...
Essential Minerals for Bone Health
Calcium and Phosphorus
Calcium is a critical component of bones, especially in the form of calcium phosphate and calcium carbonate. Since the body cannot make calcium, it must be obtained from the diet. However, calcium cannot be absorbed from the small intestine without...

