Cartilage is also aneural — meaning that it has no nerve supply. Because of the lack of nerve endings, pain is generally not felt when cartilage is damaged until it has been worn down significantly. Pain is felt when faulty movement at the injury site has started to impact another tissue in the area, such as underlying bone or associated ligamentous tissue. Inactivity has negative effects on joint cartilage. Lack of movement or of weight bearing can cause thinning of cartilage, making it susceptible to injury.
Therefore — even fairly immediately after injury — exercises that encourage joints to move throughout their range of motion and that involve some degree of load bearing through the joint surfaces help cartilage to heal.
Increased stresses to healing cartilage tissue then need to proceed in a very gradual pattern to protect the slowly healing tissue.
Nerve Healing Considerations Nerves conduct signals from your brain to your muscles, allowing movement. Nerves also conduct messages towards the brain, relaying information from muscles, skin, and joints about temperature, pressure, pain, body position, and body movement.
Some nerves are quite long — extending for instance from the base of the spinal cord all the way down to your toes. There are multiple areas in the body where nerves can become entrapped or pinched when an injury occurs. Over-stretching a nerve can also cause it to be injured. An injured nerve can cause pain as well as other symptoms such as numbness, tingling, or muscle weakness.
Sometimes nerve tissue is injured only in a small region. Other times, the effects of an injury can cause problems along the entire length of the nerve. Normalizing nerve mobility can also improve the conduction of messages sent both towards and away from the brain. Too much stress on a healing nerve can cause increased pain and nerve reactivity. Rehabilitation activities targeted towards nerve tissue need to be prescribed carefully — often in short intervals initially. But it is a bit different from the other connective tissues.
Cartilages are avascular. That means they have no blood supply. They get nourishment from adjacent connective tissues like from perichondrium or synovial fluid. So, it can easily be imagined that they are always in short of nutrition. Being always in scarcity the cells of cartilage chondrocytes exhibit low metabolic activity. After damage tissues heal by regeneration or scar formation.
Chondrocytes are not that able. So, cartilages don't regenerate except in small children. Chondrification also known as chondrogenesis is the process by which cartilage is formed from condensed mesenchyme tissue.
A chondrocyte: A chondrocyte, stained for calcium, showing its nucleus N and mitochondria M. Mesenchyme tissue differentiates into chondroblasts and begins secreting the molecules that form the extracellular matrix ECM.
Mesenchymal stem cells MSCs are undifferentiated, meaning they can give rise to different cell types. Under the appropriate conditions and at sites of cartilage formation, they are referred to as chondrogenic cells. During cartilage formation, undifferentiated MSCs are highly proliferative and form dense aggregates of chondrogenic cells at the center of chondrification.
These condrogenic cells then differentiate to chondroblasts, which will then synthesize the cartilage ECM. Cartilage: Hyaline cartilage showing chondrocytes and organelles, lacunae and matrix. The extracellular matrix consists of ground substance proteoglycans and glycosaminoglycans and associated fibers, such as collagen.
The chondroblasts then trap themselves in lacunae, small spaces that are no longer in contact with the newly created matrix and contain extracellular fluid. The chondroblast is now a chondrocyte, which is usually inactive but can still secrete and degrade the matrix depending on the conditions. The majority of body cartilage is synthesized from chondroblasts that are largely inactive at later developmental stages compared to earlier years pre-pubescence.
The division of cells within cartilage occurs very slowly. Therefore, growth in cartilage is usually not based on an increase in size or mass of the cartilage itself. Remodeling of cartilage is predominantly affected by changes and rearrangements of the collagen matrix, which responds to tensile and compressive forces experienced by the cartilage.
Cartilage growth thus mainly refers to matrix deposition, but can include both growth and remodeling of the ECM.
Early in fetal development, the greater part of the skeleton is cartilaginous. This temporary cartilage is gradually replaced by bone endochondral ossification , a process that ends at puberty. In contrast, the cartilage in the joints remains permanently unossified during life. Once damaged, cartilage has limited repair capabilities because chondrocytes are bound in lacunae and cannot migrate to damaged areas. Also, because cartilage does not have a blood supply, the deposition of new matrix is slow.
This condition occurs when the cartilage that connects the ribs to the breastbone becomes inflamed. While the condition is usually temporary, it can become chronic. The condition causes uncomfortable chest pain. This condition is usually due to degenerative changes that occur as a side effect of aging. Other times, a person may have a severe accident or back injury that can cause a herniated disk.
This condition causes severe pain in the back and often down the legs. Steps like maintaining a healthy weight, practicing flexibility and strength-training exercises, and avoiding overtraining may help to reduce the rate at which cartilage breaks down. The cartilage cells known as chondrocytes do not often replicate or repair themselves, which means damaged or injured cartilage will not likely heal well without medical intervention. Over the years, doctors have found some methods that can stimulate new cartilage growth.
These techniques are usually used for articular cartilage on the joints. Examples include:. This procedure involves using a special high-speed instrument called a burr to create small holes below damaged cartilage to stimulate cartilage repair and growth. This cartilage repair technique requires two steps. First, a doctor removes a healthy piece of cartilage from a person and sends the cartilage sample to a laboratory. The person then goes to surgery where the damaged cartilage is removed and replaced with the newly grown cartilage.
A surgeon also performs other repairs. Because this approach requires multiple surgical procedures, doctors usually only perform it on younger individuals who have a single injury that is 2 centimeters or greater. This surgical technique involves removing damaged cartilage and then making small holes just beneath the cartilage in an area of bone known as the subchondral bone. This creates a new blood supply that will ideally stimulate healing.
The drilling approach is similar to microfracture.
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