Cartilage: anatomy, role, can we rebuild our cartilage?

Definition: what are cartilage and chondrocytes?

The cartilage is part of the connective tissue of the human body. “This tissue is intended to be both hydrated and fibrous (collagen fibers).”, specifies Dr Noamane Moudden, sports doctor specializing in sports traumatology at the Drouot Laffitte Clinic. “Cartilage is made up of only one type of cell, the chondrocyteswhich are the cells allowing the production of the extracellular matrix, and therefore, of cartilage..

THE chondrocytes allow the manufacture of cartilaginous structure. We also find collagen fibers in the composition of cartilage as well as complex sugars called glycosaminoglycans. It is also a tissue very rich in water and supplied by synovial fluid.

What are the different types: where is the cartilage located?

Hyaline cartilage: knees, hips, shoulders

There are different types of cartilage in the body. The most common is the cartilage hyaline, which covers the ends of bones and joint areas. This tissue is white, pearly, smooth and poorly vascularized. “This cartilage plays an important transitional role between the bone and the movement zone. THE cartilage hyaline is mainly located at the level of kneesof the hips and shoulders”.

Fibrocartilage: menisci and pubic symphysis

The second type of cartilage is fibrocartilage or fibrous cartilagewhich we find for example at the level of meniscifrom symphysis and intervertebral discs. Fibrocartilage is, as its name suggests, very rich in collagen fibers.

Elastic cartilage: ears, nose

The third type of cartilage is elastic cartilagewhich we find mainly at the level of the pavilion of the earfrom Eustachian tube a you nez. It is also present in the epiglottis, trachea or bronchi. The elastic cartilage has a rubbery texture.

Growth plate

“There is yet another type of cartilage, which is the growth platefound in children”, explains Dr. Moudden. “These are areas of cartilage (growth plate) located mainly in the os longs and allowing the bone growth, by promoting the lengthening of bones. With the arrival of new hormonal concentrations specific to adulthood, the growth cartilages disappear, the ossification nuclei fuse and the bones have reached their final size..

What is the role of cartilaginous tissue?

As the sports doctor points out, each cartilage is different and each of them has its own properties. At the joint level, the cartilages provide flexibility and range of motion, compared to bone which is rather rigid. Cartilage, with its smooth surface, also limits friction/friction. The cartilage distributes the compressive forces by offering a greater sliding surface, we speak of joint congruence. Typically, the menisci make the joint between the two bones andincrease the contact surface. It’s the same thing at the shoulder, at the level of the glenoid labrum, where the cartilage increases the joint surface.

Cartilage does not really play the role of shock absorber, on the contrary, it tolerates compressive stresses very poorly; except at the level of the menisci and especially the intervertebral discs. In the nose, for example, the cartilage provides flexibility, otherwise it would break at the slightest impact.

What are joint cartilage diseases?

Arthritis

Cartilage is the target of numerous inflammations, called inflammatory arthritis. This could be:

• Rheumatoid arthritis ;
• Juvenile arthritis;
• Ankylosing spondylitis ;
• Psoriatic arthritis;
• Drop.
• Infectious arthritis, particularly serious, etc.

Degenerative osteoarthritis

Osteoarthritis is a degenerative disease of the joints and surrounding tissues, such as cartilage, which decrease in thickness, causing pain, swelling and stiffness. These symptoms are accompanied by a reduction in the patient’s ability to move. Osteoarthritis most often affects the knees, hips, hands and spine. For this disease which affects more than 4.6 million French people, researchers are trying to better understand the mechanisms of osteoarthritisbut also to develop new treatments, based in particular on the development of biomaterials.

What are the most common cartilage injuries or trauma?

THE cartilage lesions mainly affect the cartilage of the knee, shoulder and spine, particularly in athletes who repeatedly or intensively use their joints.

Knee cartilage lesions

• Patellar syndrome

“In sports medicine, the most frequent reason for consultation concerns knee cartilage injury. This mainly concerns patellar syndrome, in which the ball joint frictions. This injury, although benign, is painful and embarrassing for the patient. Patellar syndrome can occur after a small shock to the cartilage of the knee, sometimes requiring painkillers, but also the placement of a knee brace to stabilize the kneecap.

As the specialist doctor advises, the mistake would be to stop doing sport, the risk being that the pain will last longer. The generating sport is running. Generally, this type of patellar pain lasts two to three months, then heals, without systematic recurrence.

• Meniscal lesions

THE meniscal lesions are damage to the meniscus, a flat cartilage that is located between the upper and lower bones of the leg. Over time, the menisci wear out, becoming more and more fibrous and less and less elastic. “The meniscus will tend to crack and break. Meniscal lesions rarely become pathological after the age of 35. Lesion of the superior horn of the internal meniscus is one of the most frequent reasons for consultation, often with a degenerative cause. The lesion of the external meniscus is more worrying, especially in a young subject. It can cause early decompensation with progression to osteoarthritis.details Dr Moudden.

Shoulder cartilage damage

In the field of sport, in volleyball, basketball, tennis, climbing or even javelin, the person uses the arm. This is an external elevation of the shoulder, which can be a source of excessive stress. “The gesture is conflicting, it crushes the glenoid labrum of the shoulder on its posterior side, and this gesture is potentially dislocating: it tends to make the shoulder come out of its joint. There shoulder dislocation is very common, because to obtain power in their movements, athletes go very far in external rotation of the arm”.

Cartilaginous damage to the ears

The ear cartilage can break despite its elasticity. A hematoma can then form. Whether or not this hematoma is removed, the cartilage heals. The scar area becomes more and more fibrous and hypertrophied. The cartilage becomes larger and stiffer, but also more vulnerable to damage.

Each joint is susceptible to damage or injury, such as the hip, ankle or jaw joints (the damaged small meniscus is then very painful). Treatments are considered when the lesions are painful, extensive and significant.

What are the cartilage tests?

The reference cartilage examination is l’arthroscanner. “However, it requires injecting a contrast product into the joint. This is why MRI is easily offered, as it is non-invasive. The MRI gives us a first glimpse of the lesions.”

Other examinations of cartilage lesions may be offered, such asarthro-IRM. In cases of osteoarthritis when the lesions are extensive, the simple x-ray will be prescribed in order to assess the impact on the entire joint.

Treatment: how to repair cartilage?

Can cartilage regenerate?

The cartilage does not repair itself and the cells that compose it do not multiply. “Officially, we do not yet know how to regenerate cartilage.” admits the specialist. Cartilage regenerates little and heals with difficulty, unlike bone, as indicated by Inserm. In adults, the spontaneous regeneration of cartilage is difficult. Indeed, cartilage seems to be devoid of any healing process, notably due to the absence of innervation and vascularization. In other words, it has no nerves or blood vessels. It feeds on synovial fluid molecules, the latter penetrating the surface of the cartilage.

However, scientific research is very active, in particular because of the numerous inflammatory (arthritis) and degenerative (osteoarthritis) pathologies from which millions of people in Europe suffer.

How to quickly regenerate damaged cartilage?

First of all, the preservation of cartilage involves prevention, although we cannot prevent injuries. According to the specialist doctor, sport has a certain benefit in preventing cartilage lesions, but especially associated pain. A…