Subchondral Cyst

Facts about the Subchondral Cyst


There are many common forms of cysts, but many people have no information on one called a subchondral cyst.  This may be because they are not easily diagnosed without the benefit of a bone scan since this type of cyst occurs in the joints of bone.


What are cysts?

Containing liquid, gaseous or semi-solid substances, cysts are typically referred to as abnormal enclosed sacs that are found within tissues of the body.  They can vary in size; some are microscopic while others have been known to grow so large as to actually move internal organs from their normal position.  While they are found within body tissue, they are not considered as part of the tissue since cysts have their own distinct “walls” that are separate from the tissue in which they are found.


There are numerous reasons why a cyst might form. It could be as simple as an infection or as serious as a tumor.   In most cases, the sacs are benign or non-cancerous.  There are, however, cysts that have the potential of being malignant.  For this reason, it is important to see your medical professional when any unusual growth is noted on your body.


Certain types of cysts occur in locations within the body that are not able to be seen by the naked eye.  Internal cysts may not display any symptoms and will, therefore, go unnoticed until some type of imaging scan is completed.  One such type in this category is a subchondral cyst.  These form in spaces within the joints; spaces that are normally occupied by cartilage to cushion the bone end from another adjoining bone.  Formation of these cysts is caused when that cartilage begins to wear away and the conflict of bone on bone occurs.

Causes for the development of the cyst

These sacs that grow in the subchondral layer of bone just beneath the cartilage are most often the result of a degenerative disease called osteoarthritis.  At the onset of this condition, many changes occur in the subchondral layer of bone that induce a higher than normal density of the bone, including an increased flow of blood as the body attempts to heal itself.  A sac filled with a thick liquid material develops within and pushes out from the joint, resulting in pain and lessened mobility of the joint.


Osteoarthritis is the leading cause for this type of cyst.  It occurs primarily in older adults aged 40 to 60.  There is no specific treatment for this condition; rather, they are treated on an individualized basis.  The cysts are not drained as other types are to reduce or eliminate the presence of the sacs, as this could induce infection.



People who develop these cysts from the onset of osteoarthritis are likely to experience pain in the affected joints during movement.  The area that the joint is located may also feel tender to the touch and feel stiff after periods of non-movement.  As the cyst grows in size, there will likely be a loss of mobility, and a loss of full range of motion for that particular joint.  These symptoms will still exist and may worsen after the cyst has diminished because of the deterioration of the joint cartilage itself.  Any bone joints can be affected by the cysts, but it is the knees and hips that are most commonly the target.



In many cases, no treatment is initiated.  The cysts will frequently shrink and sometimes disappear on their own.  When pain becomes severe, often NSAIDS (non-steroidal anti inflammatory drugs) are prescribed for the individual.  In addition, decreasing the amount of activity that the joint would be engaged in helps to alleviate pain and stiffness.  It is important to note that, while the subchondral cyst may go away on its own, the disease osteoarthritis does not.  The disease will increasingly grow worse as time goes on, although there are successful treatments in slowing its progression.


In rare cases, the cyst within the joint space can be surgically removed, although this action is not one that is recommended or often performed.


Living with the cysts

As the cysts play a distinctive role in this degenerative disease, it can be expected that most individuals diagnosed will be, at some point, dealing with the complications they can create.  One of the most disconcerting is the fact that bone and joint deformities are attributed to the development of the fluid filled sacs. It is important that the individuals afflicted with osteoarthritis be continually evaluated by their doctor to treat their condition as needed.


The formation and the discovery of a subchondral cyst generally occur at the earliest phases of the disease.  When joint stiffness and / or pain lasts more than a week or two, it is best to schedule an appointment with your doctor for evaluation as soon as possible.  Joint pain that is caused by the development of a subchondral cyst is indicative of the disease called osteoarthritis.  An early diagnosis and plan of treatment can be of great help in dealing with the symptoms created from the disease as well as alleviating the pain and discomfort they cause.