What is Subchondral Bone Damage?
Osteoarthritis (OA) is commonly referred to as wear-and-tear arthritis.
However, researchers now understand that it is not entirely about worn cartilage.
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This article explains what the subchondral bone is and how subchondral bone damage contributes to OA.
It will help you to better understand what happens to the subchondral bone in osteoarthritis.
What Is Subchondral Bone?
Subchondral bone is the layer of bone just below thecartilagein a joint.
“Chondral” refers to cartilage, while the prefix sub means below.
Subchondral bone serves as a shock absorber in weight-bearing joints like the knees.
The bone has many blood vessels to supply it with nutrients and oxygen, and to take away wastes.
These vessels provide over half of the hydration, oxygenation, and glucose for the cartilage.
How Osteoarthritis Affects Subchondral Bone
In osteoarthritis, the subchondral bone becomes thicker than usual.
Subchondral bone attrition is the flattening or depression of the bone surface that forms part of a joint.
This occurs in earlyknee osteoarthritisand indicates the potential for cartilage loss and misalignment of a knee compartment.
The subchondral bone is key to cartilage and joint health.
Subchondral Conditions Associated With OA
Several other subchondral conditions are associated with osteoarthritis.
These conditions are typically seen as part of a pattern with OA that leads to a diagnosis.
One theory is that wear and tear on the knee causes microfractures that require a constant state of repair.
This cellular activity produces enzymes and proteins that may have further effects on the adjacent cartilage.
Subchondral Cyst
Asubchondral cystis often seen in osteoarthritis.
This is a fluid-filled sac that extends from the joint, sometimes called a bone cyst.
However, cartilage and subchondral bone damage are key factors leading to the development of subchondral cysts.
Subchondral Sclerosis
Subchondral sclerosisoccurs because of increased bone density or thickening in the subchondral layer.
This, in turn, can lead to deformity and subchondral bone irregularity.
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