Osteoarthritis: Causes and Treatment Options

What is Osteoarthritis?

Osteoarthritis is a joint disorder where the hyaline joint cartilage undergoes often progressive and partially irreversible damage (wear and tear) due to various causes.

This leads to changes in the joint (subchondral bone, capsule) and its surroundings (ligaments, muscles).

J. Lengerke 21:37, May 27, 2009 (CEST), Roe-heberden, CC BY-SA 3.0 DE

Common symptoms, which usually increase gradually, include start-up and load-related pain which worsens over time, movement restrictions and stiffness, possibly contour enlargements, thickening, and swelling. Later on, this may lead to misalignments and instabilities.

Types and Terminology:

Primary Osteoarthritis: The development is idiopathic (meaning without a discernible cause), without additional impacting factors.

Secondary Osteoarthritis: As a result of another disease or cause (e.g., due to arthritis, trauma with joint injury).

Polyarthritis: When multiple joints of the body are affected.

Activated Osteoarthritis: A "silent" osteoarthritis can suddenly cause discomfort due to an event (mostly trauma, overload). This is usually associated with signs of inflammation (swelling, effusion, overheating, rest pain).

The Development of Osteoarthritis

There are various hypotheses for the development of degenerative changes in the joint cartilage and osteoarthritis. It appears osteoarthritis may arise and begin from both sides of the joint: on the one hand from the cartilage surface (especially in traumas, under- and overloading) and at the same time from the bone (shift of the growth zone).

Significant main reasons are suspected to be:

• Reduced alternation between loading and unloading

• Increasing ossification of the joint cartilage

• Traumas

Reduced Alternation Between Loading and Unloading

Both underloading and age-related degeneration, as well as overloading, are included in this group.

As often mentioned, underloading may be one of the biggest threats to the hyaline joint cartilage in our western world. By sitting too much, our joint cartilage is not properly nourished. This inadequate supply has long-term negative effects on the construction and stability of the hyaline cartilage! Due to insufficient pressure changes, cartilage cells are not sufficiently stimulated for synthesis activity. And due to poor fluid transport from the subchondral bone into the cartilage, they also receive insufficient nutrients. As a result, the cells produce too little matrix, specifically the ground substance! Without ground substance, less water can be bound within the cartilage, which reduces the tension of the collagen network. The cartilage becomes more deformable. And with this increased deformability, the load on the individual collagen fibrils increases! This may cause damage to them.

Age also plays a role here: As people age, they tend to move even less. Older cells produce less matrix and ground substance, which intensifies this issue…

Overloading

If a malnourished and untrained cartilage is suddenly subjected to a heavy load, the limit of load-bearing capacity is quickly reached and exceeded.

The resulting overload has a traumatizing effect on the collagen network: the first area where damage often occurs is the transition zone (See Blog Joint Cartilage Zone II). Damage in this area suddenly allows the transition zone to bind more water (as it is no longer held back by the now defective collagen network). Increase in water in Zone II also increases the tension on the superficial cartilage zone from below, pushing it towards the joint surface. The cartilage becomes soft and deformable in this area, and it's only a matter of time before damage manifests.

If cartilage material, even tiny abrasion particles, enters the joint fluid (synovia) and comes into contact with the capsule, the body perceives it as foreign material. The capsule responds with inflammation (synovitis).

If pieces of cartilage detach, the known holes and cracks associated with osteoarthritis form. More and more, the cartilage cannot sufficiently fulfill its protective function, and the subchondral bone is subjected to increased stress. As a result, further damage occurs in these zones further down, along with increasing load-related pain.

All these factors bring changes within the cartilage itself. This can lead to damage to the collagen network in the joint cartilage and reduced quality. With potentially reduced synthetic activity, matrix production may be diminished or disturbed, but changes may also originate from the bone or the vascular and nervous system. Or after accidents with compressions and strong impacts involving the joint:

Ossification

Another cause of osteoarthritis can originate from changes in the bone. X-rays show narrowing of the joint space as the first sign. An enlargement of the mineralized cartilage zone is also visible, with a reduction in the softer cartilage zone.

Due to this reduction in the soft area of the joint cartilage, which is supposed to absorb the pressure load on the underlying bone, the stress during mechanical loading is correspondingly greater. As a result, the load limit can be reached or exceeded more quickly, leading to damage to the collagen network.

By thickening the mineralized zone, osmosis and diffusion processes between the bone and cartilage zones are also reduced, leading to poorer synthesis activity - with mentioned consequences and effects.

Traumas

In addition to the slow changes mentioned above, which lead to damage, trauma in sports or everyday life can also injure and damage the hyaline cartilage. These injuries can result in premature osteoarthritis.

Treatment Options

The extent to which complete healing and regeneration of injured cartilage is possible depends on the size and progression of the injury.

In osteopathy and physiotherapy at BodyLab Zurich, the focus is on analgesia, mobilization, relief, and training, depending on the current phase and stage. The often-restricted joints and shortened muscles are treated and stretched using manual techniques to improve the range of motion. Targeted exercises enhance muscle development, stability, and load capacity.

Orthopedic insoles are further aids to potentially achieve an improvement in posture and thus a pain reduction. Walking sticks can provide acute relief.

The instruction and education of the patient with home exercises and behavioral rules are also an important component of therapy.

Specific Forms of Osteoarthritis and Their Medical Names

• Spondyloarthritis: Facet joint osteoarthritis, osteoarthritis of the spinal joints.

• Omarthrosis:  shoulder joint (glenohumeral)

• Rhizarthrosis:  thumb saddle joint (CMC joint I)

• Bouchard's osteoarthritis: finger middle joint (PIP joint)

• Heberden's osteoarthritis: finger end joint (DIP joint)

• Coxarthrosis:  hip joint

• Gonarthrosis:  knee joint

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Cover Image Credit

J. Lengerke 21:37, May 27, 2009 (CEST), Roe-heberden, CC BY-SA 3.0 DE