Osteoarthritis: Causes and Treatment Options

What is osteoarthritis?

Osteoarthritis is a joint disease in which, due to various causes, the hyaline articular cartilage suffers often progressive and partly irreversible damage (wear and tear).

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

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

Common symptoms, which usually increase gradually, are startup and stress pain that intensifies over time, restricted movement and stiffness, possible contour enlargement, thickening, and swelling. Consequently, this can lead to deformities and instabilities later on.

Distinctions and classification:

Primary osteoarthritis: The development is idiopathic (meaning without an identifiable cause), which means there are no additional contributing factors.

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

Polyosteoarthritis: When multiple joints in the body are affected.

Activated osteoarthritis: A "silent" osteoarthritis can suddenly cause symptoms due to an event (usually trauma or overload). This is usually accompanied by signs of inflammation (swelling, effusion, localized heat, resting pain). 

Development of osteoarthritis

There are various hypotheses for the development of degenerative changes in joint cartilage and osteoarthritis. It seems that osteoarthritis can originate and begin from both sides of the joint: on one hand, from the cartilage surface (specifically in cases of trauma, under- and overloading), and on the other hand, simultaneously starting from the bone (shift of the growth zone).

The major key causes are suspected to be:

• Reduced alternation between loading and unloading

• Progressive ossification of the joint cartilage

• Trauma

Reduced alternation between loading and unloading

Underloading, age-related degeneration, and overloading all fall into this category.

As frequently mentioned, underloading is perhaps one of the greatest threats to hyaline joint cartilage in our modern Western world. Due to our highly sedentary lifestyles, our joint cartilage is no longer properly nourished. In the long run, this poor supply has a negative impact on the structure and stability of the hyaline cartilage! Because of the lack of alternating pressure, the cartilage cells are not stimulated enough to perform synthetic activity. Furthermore, due to the poor transport of fluid from the subchondral bone into the cartilage, they receive too few nutrients. As a result, the cells produce insufficient matrix, especially ground substance! The lack of ground substance means less water can be bound within the cartilage, which decreases the tension of the collagen network. The deformability of the cartilage increases. And this greater deformability increases the load on the individual collagen fibrils! This makes them highly susceptible to damage.

Age also plays a role here: as we age, we tend to move even less. And older cells produce less matrix and ground substance, which intensifies this whole issue...

Overloading

When a heavy load is suddenly placed on undernourished and untrained cartilage, the limit of resilience 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). Due to damage in this area, the transition zone can suddenly bind more water (since it is no longer restricted by the now-damaged collagen network). This larger accumulation of water in Zone II also increases the tension on the superficial cartilage zone from below, pushing it toward the joint surface. The cartilage in this area becomes soft and deformable, and it is only a matter of time before damage manifests.

If cartilage material, even the smallest wear particles, enters the joint fluid (synovia) and comes into contact with the capsule, it is treated by the body as foreign material. The capsule responds with inflammation (synovitis).

If pieces of cartilage detach, the holes and tears characteristic of osteoarthritis occur. Increasingly, the cartilage can no longer sufficiently perform its protective function, and the subchondral bone is exposed to increased stress. This leads to further damage in these deeper zones and escalating pain under load.

All of these factors bring about changes in the cartilage itself. Consequently, the collagen network in the joint cartilage can suffer damage and experience a reduction in quality. Due to potentially reduced synthetic activity, matrix production can be diminished or disrupted, but changes can also originate from the bone or the vascular and nervous systems. Or following accidents involving compression and heavy impacts with injuries and joint involvement: 

Ossification

Another cause of osteoarthritis can stem from changes in the bone. On X-rays, a narrowing of the joint space is visible as the first sign. An enlargement of the mineralized cartilage zone alongside a decrease in the softer cartilage zone is also evident.

This reduction of the soft area of the joint cartilage, which is supposed to absorb the pressure load on the underlying bone, means that the strain under mechanical load is correspondingly greater. As a result, the limit of resilience can be reached or exceeded much faster, which in turn leads to damage of the collagen network.

This thickening of the mineralized zone also reduces the osmosis and diffusion processes between the bone and the cartilage zones, which results in poorer synthetic activity – with all the aforementioned consequences. 

Trauma

In addition to the slow-developing changes mentioned above that lead to damage, trauma in sports or everyday life can of course also injure and damage the hyaline cartilage. This damage can lead to premature osteoarthritis.

Treatment options

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

In osteopathy and physiotherapy at BodyLab Zurich, the focus lies on pain relief, mobilization, unloading, and targeted training, depending on the current stage and phase. The often restricted joints and shortened muscles are treated and stretched using manual techniques, and the range of motion is improved. Customized exercises are used to build muscle, improve stability, and boost physical resilience.

Orthopedic insoles are another excellent tool to optimize posture and thus achieve pain reduction. Walking sticks can provide acute relief.

Educating and empowering the patient with home exercises and behavioral guidelines is also a key component of our therapy.

Specific forms of osteoarthritis and their medical terms

• Spondylarthrosis: Facet joint osteoarthritis, osteoarthritis of the spinal joints

• Omarthrosis:  Shoulder joint (glenohumeral)

• Rhizarthrosis:  Thumb carpometacarpal joint (CMC joint I)

• Bouchard's osteoarthritis: Proximal interphalangeal joint (PIP joint)

• Heberden's osteoarthritis: Distal interphalangeal joint (DIP joint)

• Coxarthrosis:  Hip joint

• Gonarthrosis:  Knee joint

Whenever you need us, we are here to support you!

Your BodyLab Team, your specialists for movement and physical complaints

Osteopathy and Physiotherapy | Rehabilitation and Training

Zurich Altstetten

Cover image credit

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