Subchondral geodes - also called subarticular pseudocysts, subchondral cysts or more simply bone cysts - represent an important sign of arthrosis (osteoarthritis) and other joint diseases, such as gouty and rheumatoid arthritis.
The term "geodes", typically European, inconvenient a comparison with mineralogy, where the geode is a small hollow rock bordered by crystals. In fact, geodes are cystic spaces that form in the subchondral bone, that is underlying the articular cartilage; similar to gaps or cavities, on radiological examination the geodes appear as multiple radiolucent areas of various sizes, expression of
- a more or less marked bone resorption, with the interposition of fibrous tissue
- possible accumulation of synovial fluid that has penetrated from the joint space
These cysts are often multiple, varying in size, and pyriform in appearance.
Causes of origin
But why are geodes formed? It is believed that during the osteoarthritis process the origin of the bone cysts is linked to the penetration of synovial fluid into the subchondral bone affected by bone microfractures which, added to the vascular insufficiency of this area, produce cysts that can secondarily communicate with the joint.
- Genetic predisposition + Joint incongruity, Overload or Obesity → † "wear and damage of articular cartilage →" reduction of joint thickness + release of inflammatory mediators → increase in turnover of "subchondral bone (underlying the cartilage) → † formation of osteophytes + areas of microfractures with necrosis, bone resorption and subsequent penetration of the synovial fluid, favored by cracks present on the pathological cartilage surface, in correspondence with the areas of greatest load → † "formation of bone cysts (geodes) that initially communicate with the" joint but which later they can close due to the deposition of fibrous tissue
- narrowing of the joint line
- sclerosis of the subchondral bone
- formation of osteophytes at the joint margin
Osteophytes are beak- or claw-shaped marginal osteocartilaginous proliferations that form in an attempt to increase joint contact surfaces. Thus, bone cysts can be interpreted as the result of a "saving" of the bone which, in an attempt to have greater resistance in some areas, carries out a large resorption in others.
In the absence of degenerative signs of the bones or the articulation studied, the geodes can be considered benign neoformations, highlighted by the term "aneurysmal bone cyst", whose origin is still uncertain.
Treatment
To date, there is no simple and effective cure for osteoarthritis and bone and cartilage alterations related to it; once started, cartilage degeneration is almost unstoppable and irreversible, especially when signs of osteophytes and geodes are already evident. therapeutic aids, however, it is possible to slow down the phenomenon
- anti-inflammatory drugs, topical application of capsicin, infiltration of hyaluronic acid, reduction of body weight in case of obesity, constant physical activity that includes proprioceptive and mobility exercises avoiding excessive overloads, correction of any postural defects, integration of glucosamine and chondroitin sulphate for oral, alkaline diet rich in omega-three
or proceed with the surgical replacement of the joint damaged by the geodes with a mechanical prosthesis.
