The human body is a marvel of design both externally and internally. Take the joints between our long bones, for example. The knee is a good illustration, but the elbow works as well. Here, you have large, heavy bones that come together, and must work with one another to ensure motility for the appendage (the leg or the arm).
Of course, the bones cannot simply abut one another directly. That would allow bone to grind on bone with every movement, resulting in pain, damage, and bone overgrowth as the cells attempted to repair and renew themselves. Instead, these joints are protected by a thick covering of white tissue called articular cartilage.
What Is Articular Cartilage?
As mentioned above, articular cartilage is a special type of covering designed to protect the bones within a joint. This is similar to other types of cartilage in the body, such as fibro, which is found in joint capsules and forms ligament, as well as being found in invertebral discs, and elastic cartilage, which is what makes up parts of our ears, nose and even our larynx.
The thick, heavy concentrations of cartilage within your body’s major joints is very smooth, almost slick. This allows bones to glide across the super smooth surface, without creating friction or causing damage.
Unlike other types of tissue in the body, cartilage is living, but has no blood supply attached to it. All repairs and maintenance is performed by cells that are contained within the cartilage.
How Is Articular Cartilage Damaged?
All types of cartilage in the body can be damaged. This can be quite obvious with cartilaginous structures on the body’s exterior – the ear can be cut with a sharp object, or damaged with a blunt instrument. Cartilage within the body’s joints can also be damaged in a number of ways. The most common of these is simple wear and tear over time. As we age, the healing process slows down.
Cartilage is not particularly good at healing itself in the first place, either. As time progresses, the damage to this cartilage becomes heavier and heavier, and less and less is replaced through regeneration. Eventually, it can wear away completely, leading to bone-on-bone movement, pain, and the development of conditions like arthritis.
Of course, there are other ways in which cartilage can be damaged. Traumatic injury is almost as common as wear-and-tear-related damage. For instance, athletes may sustain such injuries playing their sport, and those involved in automobile accidents may experience similar injuries.
Signs and Symptoms of Articular Cartilage Damage
A wide range of symptoms are possible for those suffering from articular cartilage damage. They range from mild to severe pain. The joint may feel stiff and be difficult to move. The range of motion available will likely be very limited, as well. Other symptoms include swelling due to fluid buildup within and around the damaged joint. The joint may also give way while being used, or it may lock in place.
Treatment Options for Sufferers
Patients suffering from articular cartilage damage may be treated with a number of different methods. Usually, the most conservative will be used first. This can include rest, ice and elevation and taking over the counter pain relievers. Steroid injections are commonly used, as well, but frequent injections may worsen cartilage health and add to the joint disease.
Physical therapy may be necessary, particularly if the damage is not extensive and the patient just needs time to heal. However, many patients will find that they require surgical intervention. There are several different surgery types that may be used depending on the joint in question and the severity of the damage to the cartilage.
Marrow Stimulation: In some cases, the surgeon may decide to drill small holes under the damaged cartilage to allow blood to seep in. This forms a clot, and stimulates the growth of new cartilage. However, this is fibro cartilage, not articular cartilage, and it will wear out more quickly, and will not provide the same smooth movement.
Debridement: This is really the process of trimming away damaged sections of cartilage and smoothing it so that it can remain in place without causing irritation.
Mosaicplasty: In this process, articular cartilage may be taken from a donor site and implanted at the damaged joint. This process is not used with serious damage, though, and works best with isolated areas of damage.
The Potential of Stem Cell Therapy
In most cases, serious damage to articular cartilage cannot be fully repaired to its original condition through surgery. However, stem cells provide an emerging option. These cells are the building blocks of the entire body, and the key to the body’s regenerative capabilities. They can heal and repair all types of tissue within the body, but can also transform into needed types of tissue.
In mid-2017, a study was published in the Journal of Orthopaedic Translation that highlighted the use of autologous stem cells in order to help regrow damaged articular cartilage in a patient whose joint was damaged by osteoarthritis. The study pointed out the potential for this method to work, but also noted a lack of existing implantation techniques and methods specific to cartilage.
In addition to the study mentioned above, over 40 other studies have been conducted or are currently in progress regarding the use of mesenchymal stem cells to heal damaged articular cartilage using various experimental methodologies and techniques.
Most of the studies mentioned rely on autologous stem cells – cells harvested from the patient in question. However, those cells lack energy for long-term regeneration, and often contain numerous mutations that can cause a negative reaction from the body’s immune system.
Allogeneic stem cells, on the other hand, are those sourced from umbilical cord blood and tissue that has been purified and banked. These are youthful, highly energetic, highly regenerative, and immune system naïve, meaning they will not evoke a negative reaction in the body.
In the end, stem cell therapy may hold the key to healing damaged articular cartilage, but more research must be conducted. In addition, no such therapies are approved by the FDA, and all are considered experimental.