Meniscus Tear

The menisci are two crescent-shaped cartilage structures located in the knee joint—one on the inner side (medial meniscus) and one on the outer side (lateral meniscus). These segments of cartilage act as shock absorbers between the thigh bone (femur) and the shinbone (tibia), helping to distribute weight evenly across the knee. The menisci also contribute to knee stability by aiding in smooth, friction-less joint movement, supporting the ligaments, and improving the overall mechanics of the knee.

Each meniscus is divided into three regions:

• Red zone: The outer portion of the meniscus, which has a good blood supply and is more likely to heal after a tear.
• White zone: The inner portion of the meniscus, which has little to no blood supply, making it harder to heal.
• Red-white zone: A transitional zone between the red and white zones.

Tears can occur in any of these regions, and the location of the tear affects the treatment options and healing potential.

Meniscus tears often result from sudden twisting, turning or squatting movements, particularly during activities, such as sports (football, basketball, skiing), lifting heavy objects, or falling. Older adults may also experience meniscus tears due to degenerative changes in the cartilage such as osteoarthritis. As people age, the meniscus becomes more brittle and prone to tearing even with normal or minimal activity. Most degenerative meniscus tears are often asymptomatic and are discovered incidentally.

Meniscus tears vary in severity and pattern. Common types include:

• Horizontal tears: These occur along the width of the meniscus and can cause the cartilage to separate into two parts. It creates a superior and inferior flap of meniscus tissue
• Vertical tears: These occur along the length of the meniscus and may extend into the red zone, potentially making them easier to repair.
• Complex tears: These are irregular tears that may involve both vertical and horizontal patterns.
• Bucket handle tears: A type of vertical tear where a portion of the meniscus flips over like a handle, often causing the knee to lock. These are relatively urgent injuries.
• Radial tears: These occur from the center of the meniscus outward, affecting its stability. Often these are difficult tears to fix because of the tear characteristics

The symptoms of a meniscus tear can vary depending on the tear’s location, size, and severity. Common signs and symptoms include:

• Pain: Sharp or dull pain in the knee, specifically along the joint line, which may worsen with activity or when the knee is twisted or with deep knee bending.
• Swelling: Inflammation and swelling in the knee, often occurring within 24 hours of the injury.
• Stiffness: Reduced range of motion, making it difficult to fully bend or straighten the knee.
• Locking or catching: The knee may feel as though it is “locking” or “catching” or becoming “stuck” during movement, often due to a piece of the meniscus interfering with joint motion.
• Instability: A feeling that the knee may give way, particularly when walking or engaging in activities that require stability.
• Popping sound: A painful popping sound or sensation may be felt at the time of injury, especially during the tearing process.

A review of your history, symptoms and mechanism of injury, starts the evaluation process. Physical examination is critical to identifying functionally limiting tears. Common tests include:

• McMurray’s Test: A maneuver in which the knee is rotated while it is bent and straightened, checking for pain or a clicking sound.
• Apley’s Compression Test: Involves compressing the knee joint while rotating the leg to assess for pain or restriction.
• MRI (Magnetic Resonance Imaging): The most effective imaging tool for diagnosing meniscus tears. It provides detailed images of the meniscus, helping to determine the tear’s size, location, and severity.