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Osteoarthritis of the Knee, what really happens?

By October 21, 2022 No Comments

Osteoarthritis is the most common progressive joint disease in the world.

It is generally characterized by joint inflammation, cartilage damage, bony response and tissue degradation.

It is currently one of the top five disabling conditions in the world affecting more than one-third of the population over 65 years of age.

Current global estimates are 150-250 million people, and some researchers estimate these numbers to be low.

Knee osteoarthritis is commonly attributed to aging and obesity. However, other risk factors exist such as genetics, joint trauma and other pathological diseases.

Recent studies have found that osteoarthritis is not only a disease of articular cartilage but one that encompasses the entire joint and surrounding tissues.

This disease is typically defined by the progressive loss of articular cartilage, thickening of the subchondral bone, formation of osteophytes, inflammation of the synovium and degradation and degeneration of the supporting structures of the joint.

It has been proposed that the degeneration of the cartilage occurs in two phases, a biosynthetic phase and a degradative phase.

In the biosynthetic phase, the chondrocytes which are the normal cells found in cartilage, attempt to repair the damaged extracellular matrix.

In the degradative phase, catabolic enzyme activity results in matrix digestion and matrix synthesis inhibition.

The two phases’ results in an erosion of cartilage and the progression of the disease. It has been thought that the erosion of the cartilage is the primary change. However, in addition there is a combination of cellular alterations and stresses on the joint which are responsible for numerous secondary modifications of the joint including remodeling of the subchondral bone, formation of osteophytes, bone marrow cystic lesions. These degenerative changes in the joint lead to alterations in the joint capsule and the synovium, ligament stress and tears, articular muscle weakness and tears in the meniscus.

Synoviocytes and chondrocytes can produce high amounts of matrix metalloproteinases.

Matrix metalloproteinases also called matrixins, hydrolyze components of the extracellular matrix. These proteinases play a central role in many biologic processes such as normal tissue remodeling, wound healing and angiogenesis and in diseases such as arthritis, cancer and tissue ulceration.

Matrix metalloproteinases are proteinases that participate in extracellular degradation. Under normal physiological conditions, the activities of MMP’s are precisely regulated at the level of transcription, activation of the precursor zymogens, interaction with specific extracellular components and inhibition by endogenous inhibitors. A loss of activity control results in disease states such as arthritis, cancer, tissue ulcers and fibrosis. Tissue inhibitors of metalloproteinases are specific inhibitors that participate in controlling the activities of MMP’s in local tissues.

The normal articular cartilage is comprised of extracellular matrix which is water, collagen, proteoglycans, calcium and chondrocytes. The rate of collagen turnover is slow and in comparison, the rate of turnover of proteoglycans is relatively fast.

 Proteoglycans help form other fibrous matrix proteins such as collagen. Proteoglycans are a major component of the extracellular matrix, the “filler” substance existing between cells. They can from large complexes with other like molecules such as hyaluronan. Evidence shows they can affect the activity and stability of proteins and signaling molecules within the matrix. They can serve as lubricants by creating a hydrating gel that helps withstand the pressures in the joint.

Osteoarthritis arises when chondrocytes fail to maintain the homeostasis between synthesis and degradation of the extracellular components. The exact cause of this imbalance is not known. Physical trauma and inflammation can increase the enzymatic activity resulting in loose particles attributed to the wear and tear attributed to the initial process. However, macrophages can usually engulf and eliminate these particles until the production overwhelms the system. These abundant amounts of particles now become mediators of inflammation stimulating the chondrocytes to release degrative enzymes. Molecules derived from the breakdown of collagen and proteoglycan are engulfed by synovial macrophages and then cause expression of proinflammatory cytokines which bind to chondrocyte receptors leading to further release of metalloproteinases and inhibition of collagen synthesis. This entire cascade of inflammatory mediators and the subsequent binding to sites causing more inflammatory cytokines to be released causes aggravating cartilage degeneration and an overall destructive environment.

Hyaluronic Acid Supplementation

Hyaluronic Acid is an glycosaminoglycan that provides joint lubrication and shock absorbency and acts as a backbone for the proteoglycans of the extracellular matrix. HA concentration can decrease by 50% or more in an osteoarthritic knee joint. Supplementation has been well documented in the literature with lasting effects in this disease.

Platelet Rich Plasma and Fibrin

Platelet Rich Plasma and Platelet Rich Fibrin are both autologous blood derived concentrates rich in both inflammatory and anti-inflammatory cytokines and growth factors. These autologous biologic products have the capability of releasing high amounts of growth factors and immune modulatory molecules that have a potential to modulate the inflammation while promoting cartilage and synovial anabolism.

Integrative Practice Solutions has been in the osteoarthritis treatment field for years. We have patented the AARP Protocol which incorporates fluoroscopically guided viscosupplement injections, coupled with unloading bracing, physical therapy and oral vitamin supplementation. The protocol has helped thousands regain their normal life without the need for surgical intervention.

Regenerative Regards,

Dr. Robert McGrath