Arthrosis has two definitions – one anatomical (part of the body) and one pathological (disease).
- Arthrosis is the term for any joint in the body(Greek ~arthros). A joint in turn is the point where two bones meet in a manner which allows for movement (articulation). The different types of joints – ball and socket, hinge, condyloid, pivot, gliding and saddle joints – articulate in specific ways.
- Arthrosis is also the term for a degenerative disease of the joint where the cartilage lining the joint erodes over time. Arthrosis is a broad term for degenerative and other diseases of the joint and is more commonly understood in the form of osteoarthritis. Therefore the term arthosis is sometimes considered to be synonymous with osteoarthritis while at other times arthrosis is seen as a prelude to or the early stages of osteoarthritis.
What is arthrosis?
Arthrosis is not a commonly used term to describe degenerative joint disease. To fully grasp the meaning of arthrosis, it is important to first understand the anatomy of the joint. The ends of bones that are part of a joint have a smooth surface known as the subchondral bone. Over it lies the articular cartilage which is strong yet flexible connective tissue that protects the bone, allows for easier movement between the surfaces and also acts as a shock absorber. It is this cartilage that is part of the articular surface and not the bone itself. The joint itself has a synovial lining (synovium) which secretes synovial fluid into the joint space that lubricates the articular surfaces and acts as a shock absorber. An outer capsule secures the joint.
Cartilage is a flexible connective tissue. The cartilage cells are known as chondroblasts which produce and release large amounts of different substances, like collagen, into the extracellular matrix. It is this matrix that is responsible for the characteristics of cartilage namely its strength and flexibility. Sometimes chondroblasts are trapped within the matrix and is then referred to as chondrocytes. The cartilage is constantly undergoing wear-and-tear. Cartilage cells, however, are constantly replenishing the cartilage matrix and therefore maintaining the integrity of the cartilage.
With age, the ability to replenish any tissue diminishes but does not cease altogether. Even in younger people, the body’s ability to replenish tissue is limited by time. If there is constant and excessive wear and tear of the articular cartilage which exceeds the replenishing time, then the cartilage will erode. This is the reason why arthrosis is more commonly seen in the elderly and more frequently in those who are very active. There are also other factors that further complicate this like inflammatory mediators which affect normal cartilage regeneration although there is little or no inflammation of the joint. Similarly if there is some underlying disease which slows or stops the activity of the cartilage cells, the cartilage will eventually wear out. As it weakens, bits of cartilage break off and float around in the joint space. The bone tissue is now exposed to the same wear and tear as the articular cartilage but lacks the flexibility and regenerative capability. It is then destroyed over time and this condition is known as osteoarthritis.
The symptoms of arthrosis develops very slowly. In the early stages of cartilage erosion, there is no symptoms. Furthermore this is a degenerative rather than inflammatory joint condition and can therefore go by unnoticed for long periods. Once the symptoms start then it gradually worsens over a long period of time.
The pain is typically isolated to the affected joint. It may be worse during and after movement of the affected joint. In milder cases, the pain may be absent until a person moves and it persists for a short while after. Rest often relieves the pain. In some cases, firm pressure on the skin over the joint will elicit pain. This tenderness of the joint is not usually accompanied by swelling as is the case in inflammatory causes of joint pain like rheumatoid arthritis.
The stiffness of the joint is another common symptom. It is most prominent after waking up in the morning and with long periods of inactivity. Moving around may ease the stiffness but excessive movement will ultimately lead to pain. The stiffness tends to worsen over time as the condition progresses. Even when the stiffness eases, the normal range of motion may not be the same. This loss of flexibility hampers a person’s level of mobility over time.
A grating sound may be heard from the joint particularly as the condition progresses. Sometimes this can also be heard as a snapping or clicking noise, depending on the joint that is affected. Normally the articular cartilages of either ends of the bone rub together to some extent. Since cartilage is very smooth and well lubricated with synovial fluid, there is usually no noise. However, with arthrosis this smoothness and easier movement is hampered thereby giving rise to this grating sound.
The larger joints like the knee become firmer to touch. Bony outgrowths, known as bone spurs, form over time. This may be felt over the skin as abnormal and hard lumps. These are late features of the disease.
Arthrosis is more often seen in the elderly and the treatment is limited. The key is to manage the pain, reduce additional stress on the joints and work with a physical therapist to improve mobility with straining the joint. Medication that may be prescribed for pain are acetminophen and non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen. Prolotherapy which helps with stimulating the articular tissue to regenerate has shown promising results but age-related slowing down of this regenerative capacity may limit its use in the elderly. Other therapies such as cortisone or lubricant injection into the joints and joint replacement are reserved for severe cases where the articular cartilage, sometimes along with the end of the bones, have been significantly eroded.
Types of Arthrosis
Arthrosis more commonly affects the joints of the shoulders, back, hips, knees and ankles. It is referred to by several medical terms depending on the site and types of joint.
This is arthrosis of the cervical vertebrae – the bones that make up the neck portion of the vertebral column. It therefore presents with a number of neck symptoms.
Cervical Arthrosis Causes
As with any type of arthrosis, cervical arthrosis arises with age-related or stress-related wear and tear of the cervical joints. This is more often associated with chronic neck problems that tend to start from earlier in life. In turn, these neck-related problems are associated with poor posture particularly with prolonged activities such as computer use.
Cervical Arthrosis Symptoms
Pain in the neck, especially in the root of the neck, along with stiffness of the neck are the main symptoms. In early life this may be largely muscular in nature. Cervical muscle spasm is a tightness of the neck muscles that causes localized neck pain, tension-type headaches and muscle stiffness. Over time, it is the cervical joints that become affected as the cartilage erodes. With cervical arthrosis, the pain may extend to the shoulders and down the arms.
Cervical Arthrosis Treatment
Resting the neck as much as possible is important. A neck brace (cervical neck collar) helps to reduce the strain on the joint but also limits mobility and is not a long term solution. Physical therapy may help with reducing any associated cervical muscle spasm and improving the mobility of the joint. Certain neck exercises, as prescribed by a physical therapist, may also be helpful in this regard. Medication is useful in reducing the pain.
The vertebral or spinal column (backbone) is made up of 33 vertebral bones that lie one on top of the other. Each bone (vertebra) is able to articulate with the vertebra above and below it which gives the backbone its flexibility. Articular processes that protrude from the back of the vertebrae are responsible for the formation of these joints. The superior articular process of one vertebra articulates with the inferior articular process of the vertebra above it. These joints are known as facet joints. When the articular surface erodes, arthrosis may arise in certain facet joints of the back and is known as facet arthrosis or facet joint arthrosis.
Facet Arthrosis Causes
The facet joints, as with any weight bearing joints, undergoes wear and tear over the time. Fortunately much of the upper body weight is transmitted across the more central parts of the vertebral column – the vertebral body and the discs between it. Poor posture, however, can cause more force to be transmitted to the facet joint than is normally the case. In most of these instances, it is seen with age and is more likely to arise in the elderly. Facet arthrosis may also arise with back injuries.
Facet Arthrosis Symptoms
Pain in the back is more common with movement, standing upright and sitting. It tends to ease when lying flat. The location of the pain depends on which facet joints are affected. It is unlikely that all facet joints will be affected to the same degree at the same time. Therefore a person will be more likely to complain of neck pain (often with headaches), mid back pain and/or low back pain. Since these facet joints are absent in the sacrum, which is composed of fused vertebrae, pain very low down the back (sacral pain) is not usually related to facet joint arthrosis.
Facet Arthrosis Treatment
Treatment is largely the same as with other types of arthrosis. A neck brace or back brace (thoracolumbosacral orthosis) may help to reduce mobility and relieve some strain on the joints. However, regular periods of rest and reduced levels of activity are the important factors here. Medication is typically used to relieve pain.
This is arthrosis of the hip joint and is among one of the more common sites of arthrosis in the elderly. The hip joint is a ball and socket joint – the ball formed by the head of the femur (thigh bone)and the socket by the acetabulum of the pelvis. It is one of the most stable and strongest joints in the body, transmitting the upper body weight down the limbs. Furthermore the hip joint sustains significant strain with movement. This makes degeneration of the joint more likely to occur.
Age-related degradation of the articular cartilage is largely associated with wear and tear. It is more likely to be seen in the elderly as the erosion occurs over decades. Coxarthrosis is also more likely to occur in professional athletes where walking and kicking are common movements. Obese people are also at risk as the greater upper body weight puts additional stress, beyond the normal strain, on the joint particularly when walking and running.
Hip pain is the main symptom – it is worse when standing, walking or running. It eases significantly when sitting and lying down. Due to the size of the joint and strain that it has to endure, a grating sound may be more audible than with arthrosis in other joints. The normal range of motion is almost always impaired and when one side is worse than the other, there may be limping.
Hip arthrosis is not easy to treat with conservative measures and medication. Although these measures may help to reduce pain and provide short term relief, the condition almost always progresses until these measures are fairly ineffective. Mobility aids like walking canes and medical walkers may help to reduce some of the strain on the joint when walking. Hip joint replacement surgery is often the treatment of choice in more severe cases that do not respond well to medication and supportive measures.
The lumbar spine (low back) bears most of the weight of the upper body. It therefore experiences significant strain throughout life. Although most types of arthrosis are seen almost exclusively in the elderly, it is not entirely uncommon for lumbar arthrosis to be seen as early as the mid to late 40s.
Lumbar Arthrosis Causes
Age-related and occupational wear and tear of the joint are the more common causes. This is not uncommon in arthrosis in general. However, lumbar arthrosis may be associated with bad posture particularly with abnormal curving of the lower back. This is also associated with abdominal obesity as the additional fat accumulation on the abdomen changes the center of gravity.
Lumbar Arthrosis Symptoms
Low back pain is the most prominent symptom. It is worse when standing upright and walking and eases with sitting and lying down. With time, there is significant loss of flexibility. Bending over may be initially be difficult but as the condition worsens a person may be unable to do so.
Lumbar Arthrosis Treatment
A lower back brace may offer some relief along with physical therapy. Patients are encourages to reduce abdominal body fat and long term weight control is essential. Medication is the main means of managing the condition. It is not uncommon for there to be lower back muscle spasm as well which often exacerbates the condition. The use of lumbar support belts may be helpful but may not be as effective in the long term or more severe cases.
Knee arthrosis, like hip arthrosis,is among the most common types of arthosis. The knee is has two articulations but it is the articulation between the femur (thigh bone) and tibia (shin bone) that are the most important in arthrosis. This joint has to withstand most of the body weight and faces significant impact during walking and running. It is therefore understandable that the knee joint is more prone to wear and tear than other joints.
Knee Arthrosis Causes
Apart from normal wear and tear, the knee joint is also more likely to experience strain in a person who is more physically active, particularly professionals sportspeople. Another important risk factor for knee arthrosis is obesity as the excessive body weight places additional strain on the knee beyond the normal wear and tear.
Knee Arthrosis Symptoms
Knee pain and tenderness are the major symptoms. It is worse with walking and eases with sitting or sleeping. Even standing still at one spot will elicit pain due to the body weight transmitted across the joint to the feet. The stiffness of the joint limits normal range of motion and impedes walking. A grating noise is also more likely to be heard in the knee joint when it is bending.
Knee Arthrosis Treatment
A knee brace may help to some extent but the key is reducing the weight on the joint. This can be partially achieved with ambulatory aids like walking canes. Immobilizing the limb as far as possible is encouraged but not practical in the long term. Medication may be used for pain management. Intra-articular injections (into the joint) of corticosteroids for pain reduction and hyaluronic acid derivatives for added lubrication are more effective for the knee joint than other sites. Surgery may have to be considered which includes reducing weight on the worn out pat of the knee (osteotomy) and knee joint replacement (arthroplasty).
AC Joint Arthrosis
The shoulder joint is made up of three bones (scapula, clavicle and humerus) and two articulations (scapula-humerus and scapula-clavicle). The smaller of these joints where the clavicle (collarbone) articulates with the scapula (shoulder blade) is known as the acromioclavicular joint. When this joint degeneratives, it is known as acromioclavicular arthrosis or AC joint arthrosis for short.
AC Joint Arthrosis Causes
Apart from age-related wear and tear, arthrosis may also develop with abnormal articulations possibly associated with falls. It is also somewhat common in weight lifters and can even develop before the age of 40 years in professional body builders.
AC Joint Arthrosis Symptoms
Initially there is tenderness of the joint and eventually pain develops during movement. This shoulder pain gradually worsens and becomes consistent, aggravated by certain movements of the upper lip, particularly when lifting the arms above the chest. Rest and immobilizing the arm helps to ease the strain on the joint. A snapping or clicking sound may sometimes be heard especially when the arm is lifted above the head.
AC Joint Arthrosis Treatment
Immobilizing the arm in an orthopedic arm sling helps with pain management by decreasing movement at the joint. Medication such as NSAIDs may also be of use in the management of pain. AC arthrosis may be treated with prolotherapy which is intended to stimulate healing of the articular surfaces of the joint. This may be less effective in the elderly.
Difference Between Arthrosis and Arthritis
- Arthritis is an inflammatory condition, arthrosis is non-inflammatory.
- Arthrosis involves the articular cartilage and sometimes bone whereas arthritis involves the joint lining.
- Arthrosis usually does not present with significant joint swelling, whereas swelling is prominent in arthritis.
- Arthrosis is due to wear and tear often related to age and overuse whereas arthritis is inflammation mediated by autoimmune, infectious and other inflammatory factors.