Cartilage damage in the knee

Knee cartilage damage means that part of the articular cartilage is damaged. The cartilage tissue consists of cells (chondrocytes) which are covered by a whitish, shiny and viscous substance.

Cartilage has the disadvantage of not being supplied with blood vessels , the arteries permeate the outer membrane of the tissue and the exchange occurs through the extracellular substance by means of osmosis.
The hyaline articular cartilage covers the joint surfaces and acts as a lubricant so that movement can be smooth and frictionless.

The loss of substance in the cartilage tissue is referred to as chondropathy, i.e. a disease of the cartilage that will not heal because cartilage cannot regenerate ; on the contrary, the clinical picture can worsen to such an extent that part of the bone is finally completely exposed without a layer of cartilage.
Today, the treatment of cartilage injuries is the subject of numerous scientific studies and is often discussed at national and international congresses.
A fibrous cartilage replacement tissue forms in the injured area, but it does not have the same elasticity as hyaline articular cartilage, is also not as smooth and tends to degenerate over time.
Now there is a risk that the joints will run like a gear without oil, which would create a lot of friction that can cause joint inflammation .


What are the causes and risk factors of cartilage damage in the knee?

The condition can result from trauma or as a result of wear and tear. Cartilage injuries can occur at any age, but in young people they are usually caused by an accident or a fall. In athletes,  lesions can occur as a result of a sprain , and excessive strain can also lead to premature wear and tear of cartilage tissue.

The factors predisposing  to chondropathy of the knee can also include malpositions of the bones (axial deviations of the skeleton), such as varus (bow legs) and valgus (knock knees) or patellofemoral pain syndrome , as well as obesity, age, autoimmune diseases such as rheumatoid arthritis , meniscectomy , laxity of the cruciate ligaments, effects of knee joint fractures , osteonecrosis, or belonging to certain occupational groups.

Physically strenuous activities or those with a high proportion of sitting accelerate the degeneration process of the cartilage. Anyone who has to lift loads
for many hours a day wears out the cartilage through overuse; On the other hand, people who sit and do not move all day have poor tissue perfusion and will develop atrophic tendencies from the lack of stimuli. Track and field athletes (short-distance, long-distance, marathon runners, sprinters) may have perforated cartilage regions after many years of sporting activity.

What are the Symptoms of Knee Cartilage Damage?

The symptoms of a cartilage injury are not proportional to its extent , a small injury can cause a lot of pain and vice versa.

The pain occurs during movement, especially when bending the knee or squatting down, and should go away during periods of rest.
The symptoms are not as obvious as with a torn meniscus  or ligament .

  • Often the only symptom is an irregular effusion (swelling). The broken cartilage fragments swarm around the knee and can cause edema.
  • The knee may have swelling in the front and back , in this case the Baker’s cyst increases in volume.
  • The pain occurs in the inside or back of the knee after exertion, such as a long walk or climbing stairs.
  • The knee can sag under the weight of the body.
  • Stray cartilage fragments or foreign objects can block the knee joint when bending and cause a lock knee.
  • The knee can make noise (crunch) when it moves, especially if the cartilage on the back of the kneecap is damaged.

In symptomatic patients, the cartilage damage does not allow sporting activities.

How is knee cartilage damage diagnosed?

It is almost impossible to determine cartilage damage through a clinical examination; there are no special movement tests.

A thorough examination of the medical history, symptoms and signs can raise the suspicion of a chondropathy, but definitive confirmation is provided by magnetic resonance imaging , which shows a reduction in the height of the cartilage tissue or, in the case of a complete lesion, the exposed bone.
Sonography is not able to show deep cartilage damage and is therefore unsuitable .
An x-ray can show the narrowing of the joint space (i.e. cartilage wear), but small tears will not be visible.

How can cartilage damage in the knee be treated?

In the past, it rarely happened that so many surgical, biotechnological and pharmacological treatment methods with numerous rehabilitation protocols followed one another and were further developed in such a short time.
The problem with cartilage is that it cannot be repaired like bone.
The aim of the therapy is to stop the progression of the cartilage damage, because the prospects would be a complete absence of articular cartilage (4th degree) and the bones rubbing together during movement.
Anti-inflammatory medications such as ibuprofen (Dolormin) or ketoprofen (Alrheumun) can provide short-term pain relief.
A pharmacological treatment byJoint infiltration of hyaluronic acid, which is an endogenous component of cartilage, could help delay surgery, which is the only permanent form of therapy in these cases.
The orthopedist can suck fluid out of the inflamed knee joint before performing the injection.

Surgical intervention of the cartilage damage on the knee

Techniques such as cartilage abrasion are left out at this point because the studies have not been able to show satisfactory results. Procedures such as microfracture, mosaicplasty and autologous chondrocyte transplantation (ACT) are currently used.

The technique of microfracture was developed by Steadman, he “drilled” the cartilaginous bone at the joint surface. This stimulated the mesenchymal stem cells, which created fibrocartilage tissue in place of the cartilage that had been removed. This newly formed tissue isn’t as elastic and smooth as cartilage, so it doesn’t lubricate the joint as well.
The technique of mosaicplasty was invented by the Hungarian Hangody, who took part of the cartilage-covered bone from a less stressed place in the knee to insert it in the area of ​​damage.

The results are good, but the patient has to undergo a long follow-up physiotherapy treatment in order for the inserted tissue to take root completely.
A group of researchers led by the Swede Peterson developed autologous chondrocyte transplantation ; in this procedure, a piece of healthy cartilage is removed and sent to a special laboratory; there it undergoes a treatment to isolate and multiply the cartilage cells (chondrocytes) so that a much larger number is available.
In a second operation, 1-2 months after the first operation, the surgeon inserts the chondrocytes at the site of the injured cartilage so that it can regenerate.
This transplantcan only be done for certain people who meet certain criteria.

5 years after the operation, the examinations show good results, this procedure can be considered reliable.
This technique has undergone various improvements, such as the material used to hold the chondrocytes at the transplant site, but the principle has remained the same.

Candidates for autologous chondrocyte transplantation must meet the following criteria:

  • Age < 40 years.
  • The injured cartilage must be at the femoral condyles.
  • The cartilage damage must be the result of trauma or osteoarthritis dissecans .
  • The patient’s menisci must be intact.
  • The knee must not show any axial deviations.
  • Excluded are overweight patients, those suffering from arthrosis , or rheumatic, metabolic or infectious pathologies.

What to do? Rehabilitation of cartilage damage in the knee

The rehabilitation is very lengthy; During the first 30-40 days, the operated leg must not be subjected to body weight, and returning to sport is out of the question in the first 10 months after the operation.
The goal is muscle strengthening and full recovery of joint function in the injured leg.
In the first phase, active and actively accompanied mobilization exercises must be carried out for the knee joint without strain, such as riding the home trainer without resistance; if necessary, physical therapies can be used to reduce the pain and swelling. Hips and ankles need to start muscle building
early .
Once the surgeon approves,  quadriceps strengthening begins in the gym or in the water, if necessary.
In this phase, the patient is allowed to ride a bicycle.
For the first two months of muscle strengthening, the exercises must be done in closed kinetic chain (ie, feet are fixed, as in leg presses and squats), after which they can be done in open kinetic chain, meaning feet are free to move during exercise, as with leg stretching (leg extension).
Magnetic therapy can be used effectively to reduce knee swelling and pain.

Natural Remedies

Natural remedies include shark cartilage, which is available as a dietary supplement. Take one tablet a day for at least 2 months.

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