Introduction
Cartilage is a flexible connective tissue that shields the bones and joints. It acts as a shock absorber throughout the body. Cartilage helps to reduce friction between the bones and joints that occurs from rubbing. Cartilage also has multiple functions, such as it enhances bone resilience and resisting compressive forces. No nerve supply is present in the cartilage, and is completely avascular (no blood supply). Cartilage usually receives nutrients through diffusion from the surrounding environment. There are chances for cartilage tears or defects during sports injuries or trauma.
Nerve Supply to Cartilage
Cartilage does not have any nerve supply. Any pain arising from cartilage trauma or injury is due to irritation of the surrounding structures or swelling in the surrounding bones and joints due to diseases like osteoarthritis.
Biphasic Model of Cartilage
Cartilage comprises a few essential components, such as proteoglycans, collagen fibers, cells, and lipids that merge to form a solid structure and a fluid component is formed by the interstitial fluid (fluid between the cells).
What Are the Different Types of Cartilage?
Different variants of cartilage present in the body are:
1. Hyaline Cartilage: Hyaline cartilage is the most specialized type with bluish to white color and smooth texture. It is made up of type two collagen fibers and proteoglycans. In younger individuals, these cartilage are moist but become very yellowish, thin, and dry with increasing age. Hyaline cartilage is present in:
-
Nose.
-
Trachea.
-
Epiphyseal growth plate.
-
Sternum.
-
Ribs (ventral part).
2. Elastic Cartilage: This cartilage type is quite resilient to pressure. It appears dull yellow with a perichondrium-like layer lining it. It is present in:
-
Ear.
-
Larynx (voice box).
-
Epiglottis.
-
Eustachian tube.
3. Fibrocartilage: Fibrocartilage is composed mostly of type one collage with very few amounts of proteoglycans. It does not have a perichondrium. This cartilage has the ability to resist tension and compression forces at a very high scale. Fibrocartilage is present in:
-
Tendons.
-
Ligaments.
-
Intervertebral discs.
-
Meniscus.
What Are the Different Functions of Cartilage?
Cartilage has different functions:
-
It helps in the lubrication of bones and joints. It prevents the friction produced between the bones and the joints from rubbing.
-
It helps in the absorption of shock and pressure from the tensile and compressive forces.
-
It acts as a supporting structure for tendons, muscles, and ligaments by keeping them united together throughout the body.
What Are the Different Conditions That Can Affect Cartilage?
A few clinical conditions that can affect cartilage are:
-
Trauma or Injuries: Any trauma or injury to the cartilage, while sports injuries or accidental falls, can result in damage to the cartilage. Any damage to the cartilage can cause restriction in the mobility of the joints or affect the range of motion.
-
Osteoarthritis: Osteoarthritis is the most common type of disease affecting the bones and the joints. The cushioning and lubricating effect of the cartilage reduces with age resulting in the weakening of the bones and the joints and increasing the risk of fracture. The decrease in the friction and lubrication of joints in elderly people can result in pain and stiffness in the joints due to bone-against-bone contact. It is initially managed by anti-inflammatory drugs and intra-articular (space between the joints) steroid injections therapy. Pharmacological therapy helps to reduce inflammatory mediators like cytokines that are released due to cartilage degeneration.
-
Herniated or Slipped Disk: Herniated or bulged disk occurs when there is tearing or damage to the cartilage between the vertebrae.
-
Achondroplasia: It is a hereditary condition affecting the cartilage. It is the most common cause of dwarfism. There is currently no cure for managing achondroplasia.
How Can Cartilage Damage Be Diagnosed?
Cartilage damage can be diagnosed by different radiographic techniques like computed tomography scans and magnetic resonance imaging.
What Is the Management of Damaged Cartilage?
A minor injury to the cartilage may heal on its own. But in a few cases where there is a crush injury or tearing of the cartilage, it needs surgical intervention because of the involvement of other surrounding structures as well. The surgeon helps to repair the cartilage and place it back to its anatomical position. The arthroscopic technique is usually used by the doctor to treat cartilage injuries. In a few cases of cartilage trauma, the surgeon might trim and reshape the sharp edges of the ruptured cartilage to restore its normal function and improve the range of motion.
How to Improve Cartilage Health?
There are a few activities that help to improve cartilage health, such as:
-
Indulging in Routine Exercises: Few stretching and warm-up exercises must be routinely done before any sports activities to maintain the health of the joints and cartilage.
-
Lifestyle Changes: A balanced and nutritious diet should be consumed to improve the bones, cartilage, and joint health. In the case of obesity (overweight), shedding a few pounds with proper diet and exercise helps to reduce too much pressure and tension over the bones and joints, resulting in improved joint strength. Strengthening of bones and joints also reduces the risk of fractures.
How Much Time Does Cartilage Repair Take To Heal After the Surgery?
As the cartilage is a completely avascular (no blood supply) structure and chondrocytes (cells present in cartilage) receive nourishment through diffusion from the surrounding environment, the healing potential of cartilage is prolonged.
Are There Any Current Biologic Approaches for Repair and Regeneration of Cartilage?
Repair and regeneration of cartilage is still a controversial discussion because of the self-limiting healing potential of the cartilage. However, there is little research that shows that stem cell therapy (mesenchymal stem cells) has shown an improved healing capacity for cartilage defects. Still further research is needed to understand the potential of stem cells as a treatment alternative for cartilage damage repair in cases of degenerative disorders like osteoarthritis, herniated disc, etc.
Conclusion
Cartilage is a flexible connective tissue that is of different variants in different parts of the body. Cartilage provides cushioning and lubrication to the joints, which results in a reduction in friction between the joints. Any damage to the cartilage due to trauma or degenerative diseases can result in pain, stiffness, and reduced joint mobility, which indicates immediate management from the healthcare provider.
