Damaged knee cartilage: what to do?

Definition: what is knee cartilage?

Cartilage is the essential part of the joint. It covers the bone ends and is a kind of “protective film”. Along with the musculotendinous structure, the cartilage allows the knee to flex-extend and rotate the thigh on the leg. It has two main functions:

► He allows the sliding of the bones without difficulty and without pain. The cartilage does not contain nerve fibers, so it cannot transmit any information to the brain, which makes movement imperceptible.

► He has an extraordinary damping and pressure distribution capacitywhich allows a reduction in the mechanical stresses imposed on the joint.

Cartilage is thick from 1 to 4 mm depending on the joints. It is composed of a matrix and specialized cells: chondrocytes. It is neither innervated nor vascularized, which is equivalent to imagining an impassable barrier with the underlying bone called the subchondral bone.

Symptoms when knee cartilage is damaged

• Discomfort, pain
• Swelling, cracking
• Decreased mobility

These symptoms are most often dependent on the degree of activity.

What are the causes of cartilage destruction?

“The destruction of articular cartilage has various causes (osteoarthritis, inflammatory or infectious arthritis, necrosis, osteochondritis, sequelae of joint trauma, tumour..) but all these causes are responsible for the appearance of the same symptoms: pain, stiffness and ultimately functional disability”explains Dr. Cattan, a knee surgeon.

What to do when the cartilage of the knee is damaged?

First of all, it should see a doctor for a clinical examination, x-rays and especially an MRI. “These examinations make it possible to make the diagnosis of damage to the cartilage, to know the cause and to evaluate the extension of the lesion and its severity. The lesion may indeed be very superficial and without symptoms and may not require treatment.“, continues our interlocutor. It can also concern the entire thickness and surface of the cartilage, sometimes even affecting the underlying bone. The cartilage presents very limited repair and regeneration abilities. A cartilage defect does not fill up spontaneously. A partially detached lesion does not heal on its own. The presence of a small lesion can be treated medically and functionally first with:

• Analgesics, nonsteroidal anti-inflammatory drugs, cortisone
• Cartilage substitutes and cartilage extracts
• Visco-supplementation (injection of hyaluronic acid)
• Injections of PRP (Platelet Rich Plasma)
• physiotherapy sessions

Surgery will be proposed in case of valve or symptomatic free fragment, or in the presence of a large cartilage defect. The goal of the operation is to restore a smooth sliding surface, thus relieving pain, blockages and swelling. It then allows normal resumption of walking and activities and avoids progressive deterioration of the joint.

Reconstruction of knee cartilage

Certain cartilage lesions of the knees can be repaired usingtransplant, in particular from an autograft. “The latter involves either taking one or more healthy osteochondral “carrots” and grafting them into the damaged area (mosaicplasty), or taking healthy cells from the patient’s cartilage to put them in culture and grow them in order to obtain them. a sufficient amount“, details the specialist. In the latter case, they will then be grafted into the damaged area of ​​the knee, after surgical removal of the cartilage that is too damaged. The cartilage will thus reform, putting an end to the transition to bothersome symptoms (pain, loss of mobility, cracking bone…). Rehabilitation and medical follow-up over several months are necessary after the operation.

Can we continue to exercise?

Gentle sporting activities such as cycling and swimming generally begin the 3rd month after the operation.
Whatever the technique, it is often necessary to wait 4 to 6 months before resuming all sporting activities.

Thanks to Doctor David Cattan, knee surgeon in Paris