Articular cartilage damage
Encyclopedia
Cartilage
structures and functions can be damaged. Such damage can result from a variety of causes, such as a bad fall or traumatic sport-accident, previous knee injuries or wear and tear over time. Immobilization for long periods can also result in cartilage damage.
Articular cartilage damage in the knee may be found on its own but it will more often be found in conjunction with injuries to ligaments and menisci. People with previous surgical interventions face more chances of articular cartilage damage due to altered mechanics of the joint
.
Articular cartilage does not usually regenerate (the process of repair by formation of the same type of tissue) after injury or disease leading to loss of tissue and formation of a defect. This fact was first described by William Hunter in 1743. Several surgical techniques have been developed in the effort to repair
articular cartilage defects.
MRI-scans are becoming more valuable in the analysis of articular cartilage but their use is still expensive and time consuming. X-rays only show bone injuries and are therefore not very helpful in diagnosing cartilage damage, especially not in early stages. The best tool for diagnosing articular damage is the use of arthroscopy
.
Doctors will often also measure the size of each defect. Defects smaller than 2 cm2, for example, are considered to be small. It is also important to remember that although the amount of damage is an important factor, the location of the defect(s) can also influence the symptoms you are getting in terms of pain and function and their repair options available.
In contrast to popular perception, pain is not a good indicator for determining the extent of articular cartilage damage. One person can have severe pain with a single small defect while another person can have very little pain with several large full thickness defects.
When the damage increases and the chondral defect reaches the subchondral bone, the blood supply in the bone starts a healing process in the defect. Scar tissue made up of a type of cartilage called fibrocartilage
is then formed. Although fibrocartilage is able to fill in articular cartilage defects its structure is significantly different to that of hyaline cartilage; it is much denser and it doesn't withstand the demands of everyday activities as much as hyaline cartilage. It is therefore at a higher risk of breaking down.
Wang et al.(2006) found that small articular cartilage defects can progress to osteoarthritis
over time if left untreated. An articular cartilage defect that initially may be small still has the potential to have a physical and chemical "domino effect" on the surrounding "normal" articular cartilage.
.
These regenerative procedures are believed to delay osteoarthritis
of injuries on the articular cartilage of the knee, by slowing down the degeneration of the joint compared to untreated damage. According to Mithoefer et al. (2006), these articular cartilage repair
procedures offer the best results when the intervention takes place in the early stages of the cartilage damage.
Cartilage
Cartilage is a flexible connective tissue found in many areas in the bodies of humans and other animals, including the joints between bones, the rib cage, the ear, the nose, the elbow, the knee, the ankle, the bronchial tubes and the intervertebral discs...
structures and functions can be damaged. Such damage can result from a variety of causes, such as a bad fall or traumatic sport-accident, previous knee injuries or wear and tear over time. Immobilization for long periods can also result in cartilage damage.
Articular cartilage damage in the knee may be found on its own but it will more often be found in conjunction with injuries to ligaments and menisci. People with previous surgical interventions face more chances of articular cartilage damage due to altered mechanics of the joint
Joint
A joint is the location at which two or more bones make contact. They are constructed to allow movement and provide mechanical support, and are classified structurally and functionally.-Classification:...
.
Articular cartilage does not usually regenerate (the process of repair by formation of the same type of tissue) after injury or disease leading to loss of tissue and formation of a defect. This fact was first described by William Hunter in 1743. Several surgical techniques have been developed in the effort to repair
Articular cartilage repair
The aim of an articular cartilage repair treatment is to restore the surface of an articular joint's hyaline cartilage. Over the last decades, surgeons and researchers have been working hard to elaborate surgical cartilage repair interventions...
articular cartilage defects.
Diagnosing articular cartilage damage (through Arthroscopy)
No non-invasive tests are currently able to diagnose articular cartilage damage. Additionally, symptoms vary considerably from person to person. Or as Dr. Karen Hambly stated:MRI-scans are becoming more valuable in the analysis of articular cartilage but their use is still expensive and time consuming. X-rays only show bone injuries and are therefore not very helpful in diagnosing cartilage damage, especially not in early stages. The best tool for diagnosing articular damage is the use of arthroscopy
Arthroscopy
Arthroscopy is a minimally invasive surgical procedure in which an examination and sometimes treatment of damage of the interior of a joint is performed using an arthroscope, a type of endoscope that is inserted into the joint through a small incision...
.
Measuring Cartilage Damage
The International Cartilage Repair Society has set up an arthroscopic grading system by which cartilage defects can be ranked:- grade 0: (normal) healthy cartilage
- grade 1: the cartilage has a soft spot or blisters
- grade 2: minor tears visible in the cartilage
- grade 3: lesions have deep crevices (more than 50% of cartilage layer)
- grade 4: the cartilage tear exposes the underlying (subchronal) bone
Doctors will often also measure the size of each defect. Defects smaller than 2 cm2, for example, are considered to be small. It is also important to remember that although the amount of damage is an important factor, the location of the defect(s) can also influence the symptoms you are getting in terms of pain and function and their repair options available.
In contrast to popular perception, pain is not a good indicator for determining the extent of articular cartilage damage. One person can have severe pain with a single small defect while another person can have very little pain with several large full thickness defects.
Consequences of cartilage damage
Articular cartilage has a very limited capacity for self repair. Small damage does not repair itself and can often get worse over time. As cartilage is aneural and avascular (does not have nerve supply), shallow damage often does not trigger pain.When the damage increases and the chondral defect reaches the subchondral bone, the blood supply in the bone starts a healing process in the defect. Scar tissue made up of a type of cartilage called fibrocartilage
Fibrocartilage
White fibrocartilage consists of a mixture of white fibrous tissue and cartilaginous tissue in various proportions. It owes its flexibility and toughness to the former of these constituents, and its elasticity to the latter...
is then formed. Although fibrocartilage is able to fill in articular cartilage defects its structure is significantly different to that of hyaline cartilage; it is much denser and it doesn't withstand the demands of everyday activities as much as hyaline cartilage. It is therefore at a higher risk of breaking down.
Wang et al.(2006) found that small articular cartilage defects can progress to osteoarthritis
Osteoarthritis
Osteoarthritis also known as degenerative arthritis or degenerative joint disease, is a group of mechanical abnormalities involving degradation of joints, including articular cartilage and subchondral bone. Symptoms may include joint pain, tenderness, stiffness, locking, and sometimes an effusion...
over time if left untreated. An articular cartilage defect that initially may be small still has the potential to have a physical and chemical "domino effect" on the surrounding "normal" articular cartilage.
Repairing articular cartilage damage
Though articular cartilage damage is not life threatening, it does strongly affect one's quality of life. Articular cartilage damage is often the cause of severe pain, knee swelling, substantial reduction in mobility and severe restrictions to one's activities. Over the last decades, however, research has focused on regenerating damaged jointsArticular cartilage repair
The aim of an articular cartilage repair treatment is to restore the surface of an articular joint's hyaline cartilage. Over the last decades, surgeons and researchers have been working hard to elaborate surgical cartilage repair interventions...
.
These regenerative procedures are believed to delay osteoarthritis
Osteoarthritis
Osteoarthritis also known as degenerative arthritis or degenerative joint disease, is a group of mechanical abnormalities involving degradation of joints, including articular cartilage and subchondral bone. Symptoms may include joint pain, tenderness, stiffness, locking, and sometimes an effusion...
of injuries on the articular cartilage of the knee, by slowing down the degeneration of the joint compared to untreated damage. According to Mithoefer et al. (2006), these articular cartilage repair
Articular cartilage repair
The aim of an articular cartilage repair treatment is to restore the surface of an articular joint's hyaline cartilage. Over the last decades, surgeons and researchers have been working hard to elaborate surgical cartilage repair interventions...
procedures offer the best results when the intervention takes place in the early stages of the cartilage damage.