Knee Cartilage Injuries
What is articular cartilage?
Articular cartilage is a highly specialized connective tissue that provides a smooth, lubricated, friction-reducing surface. Articular cartilage is found between the joints and is a vital element of a healthy joint, making possible the seamless function and mobility of the knee.
The ends of both the femur (the thigh bone) and the tibia (the shinbone) are covered with a thin layer of white articular cartilage that facilitates the smooth gliding motion of the knee joint and allows for flexibility and the ability to withstand daily wear and tear.
Cartilage (chondral) and bone and cartilage (Osteochondral) lesions of the knee are common and may lead to significant pain and morbidity. Articular cartilage has limited ability to heal itself.
Untreated, these lesions can lead to progressive cartilage degenerative joint disease and ultimately to ‘early onset’ osteoarthritis. Chondral lesions have been found in approximately 60% of patients undergoing knee arthroscopy. The injuries may be small, asymptomatic lesions, or large disabling defects affecting a major part of a knee. Isolated cartilage defects are often found in younger, more active patients, who are less likely to accept function limitations. Cartilage lesions can lead to significant pain and dysfunction.
Knee cartilage injuries can be caused by a variety of factors, often related to both acute trauma and chronic wear and tear. Here are some common causes:
- Trauma: Direct blows to the joint, such as in a car accident or a fall. Sudden twisting or bending of the knee, especially during sports activities, can cause tears or fractures in the articular cartilage.
- Wear and Tear: Over time, repetitive use and strain on the joint can lead to a gradual breakdown of the cartilage. This is often seen in athletes or individuals with jobs that require repeated knee bending or heavy lifting.
- Aging: As people age, the water content of cartilage increases, and the protein makeup changes, making it more susceptible to degradation.
- Obesity: Extra weight puts more pressure on the joints, particularly the knees, which can accelerate the natural wear and tear process of articular cartilage.
- Joint Misalignment: If the joint is misaligned, it may cause uneven pressure and wear on the articular cartilage, leading to damage over time.
- Underlying Medical Conditions: Diseases like osteoarthritis can directly cause the breakdown of articular cartilage. Other inflammatory joint diseases, like rheumatoid arthritis, can also contribute to cartilage degradation. Osteochondritis Dissecans is a condition that can develop in the knee and can cause loosening of the cartilage due to bone damage. Osteonecrosis of the femur is disrupted blood supply to the bone which causes it to die and collapses the articular cartilage.
- Genetic Factors: Some people may have a genetic predisposition that makes their cartilage more susceptible to damage.
- Previous Joint Injuries: Prior injuries to the joint may have caused changes in the joint’s mechanics or structure, leading to abnormal wear on the articular cartilage.
- Improper Training or Lack of Conditioning: Engaging in physical activities without proper training, warm-up, or equipment can lead to increased stress on the joints, potentially causing cartilage damage.
Common symptoms include pain, tenderness, swelling, stiffness, a catching and locking sensation, a grinding sensation when moving the knee, weakness or instability.
Dr. Reynolds will review your medical history, inquire about any previous knee injuries, your symptoms and activities and underlying health conditions. He will perform an orthopedic examination of the knee including palpating to detect tenderness and swelling, test range of motion and stability, and perform specific motions to identify the affected knee structures.
Dr. Reynolds will order x-rays to evaluate the bones, and an MRI to evaluate the soft tissues including the articular cartilage. Sometimes he may recommend arthroscopy to see inside the joint to evaluate the extent of the damage and provide a definitive diagnosis.
With this information Dr. Reynolds can make a diagnosis and discuss your treatment options.
Understanding the specific cause of articular cartilage damage is essential for proper treatment and prevention.