Knee Cartilage: Meniscus, Articular Cartilage, and Their Functions

What is another name for the knee cartilage?

When referring to the C-shaped, shock-absorbing structures within the knee joint, another name for the knee cartilage is the meniscus (plural: menisci). However, the knee also contains articular cartilage, which covers the ends of the bones.

The Primary Answer: The Meniscus

The term "knee cartilage" most commonly refers to the meniscus. There are two menisci in each knee: the medial meniscus (on the inner side of the knee) and the lateral meniscus (on the outer side). These structures are crescent-shaped, semi-circular pads made of fibrocartilage, a tough and flexible type of cartilage.

• Location: Situated between the femur (thigh bone) and the tibia (shin bone), they act as crucial intermediaries within the tibiofemoral joint.
• Primary Functions:
  • Shock Absorption: They distribute the forces transmitted across the knee joint during activities like walking, running, and jumping, protecting the underlying bone.
  • Load Distribution: By increasing the contact area between the femur and tibia, they help spread the load more evenly, reducing stress on specific points.
  • Joint Stability: They contribute to the overall stability of the knee, helping to prevent excessive movement.
  • Lubrication: They assist in the circulation of synovial fluid, which lubricates the joint.
• Common Injuries: Meniscal tears are very common, often occurring due to twisting motions, direct impact, or simply through degenerative changes over time. Symptoms typically include pain, swelling, clicking or popping, and sometimes a "locking" sensation in the knee.

Other Crucial Knee Cartilage: Articular Cartilage

While the meniscus is a specific type of cartilage, the knee joint also features extensive articular cartilage. This is a smooth, slippery tissue made of hyaline cartilage that covers the ends of the bones within the joint, specifically:

• The lower end of the femur (thigh bone).
• The upper end of the tibia (shin bone).
• The back surface of the patella (kneecap).
• Primary Functions:
  • Smooth Gliding: It provides a low-friction surface, allowing the bones to glide effortlessly against each other during movement.
  • Shock Absorption: It also plays a role in absorbing and distributing forces, protecting the bone underneath.
• Common Issues: Unlike meniscal tears, damage to articular cartilage often manifests as conditions like osteoarthritis. This is a degenerative joint disease where the articular cartilage gradually wears away, leading to bone-on-bone friction, pain, stiffness, and reduced range of motion. Injuries can also cause focal cartilage defects.

Why Are There Different Types?

The knee joint requires different types of cartilage because of the varied mechanical demands placed upon it.

• Fibrocartilage (Meniscus): Its dense, fibrous composition makes it ideal for handling compressive and shear forces, providing robust shock absorption and stability.
• Hyaline Cartilage (Articular Cartilage): Its smooth, resilient, and low-friction properties are perfectly suited for facilitating effortless gliding between joint surfaces, ensuring smooth movement.

Each type of cartilage plays a distinct yet complementary role in maintaining the health and function of the knee.

Maintaining Knee Cartilage Health

Protecting your knee cartilage, both meniscal and articular, is crucial for long-term joint health and mobility.

• Practice Proper Exercise Form: Incorrect technique in exercises like squats, lunges, and jumps can place undue stress on the knee joint. Focus on controlled movements and proper alignment.
• Gradual Progression: Avoid sudden increases in exercise intensity or volume. Allow your body, including your cartilage, to adapt progressively.
• Strengthen Supporting Muscles: Develop strong quadriceps, hamstrings, glutes, and calf muscles. These muscles act as natural shock absorbers and stabilizers for the knee.
• Maintain Healthy Body Weight: Excess body weight significantly increases the load on your knee joints, accelerating cartilage wear.
• Incorporate Low-Impact Activities: Balance high-impact activities (running, jumping) with low-impact options like cycling, swimming, or elliptical training to reduce repetitive stress on the cartilage.
• Ensure Adequate Mobility and Flexibility: Maintaining a full range of motion in your hips, knees, and ankles can optimize joint mechanics and reduce strain.
• Support with Nutrition: A balanced diet rich in anti-inflammatory foods, vitamins (like Vitamin C and D), and minerals can support overall joint health. Some individuals also find benefits from supplements like glucosamine and chondroitin, though scientific evidence is mixed.
• Listen to Your Body: Pay attention to pain signals. Persistent knee pain, swelling, or stiffness should not be ignored.

When to Seek Professional Advice

If you experience persistent knee pain, swelling, stiffness, difficulty bearing weight, or a "locking" or "giving way" sensation, it's important to consult with a healthcare professional. An accurate diagnosis from a doctor, physical therapist, or orthopedic specialist is essential for proper management and treatment of any cartilage-related issues.