The knee joint contains two C-shaped pieces of cartilage, the medial and lateral menisci, positioned between the thighbone and shinbone. These cartilaginous pads distribute the body’s weight, reduce friction, and provide stability, acting like shock absorbers. Meniscus tears are a common injury, affecting individuals across various activity levels and age groups.
Understanding Meniscus Tears
Meniscus tears arise from two main mechanisms: acute (traumatic) or degenerative. Acute tears occur due to sudden, forceful twisting or rotating motions of the knee, often in sports, or from direct impact. Degenerative tears develop gradually from wear and tear on the cartilage, particularly as individuals age. This process makes the meniscal tissue susceptible to tearing, sometimes even from minor movements like rising from a chair.
Meniscus tears present in various patterns, describing the shape and location within the cartilage. Common patterns include:
Radial tears, which extend across the meniscus.
Horizontal tears, which split the meniscus into upper and lower layers.
Longitudinal tears, which run along the length of the meniscus.
Complex tears, which combine multiple patterns.
The specific pattern and location of a tear influence its potential for healing and the approach to treatment.
The Most Common Meniscus Tear
The most prevalent meniscus tear, especially in middle-aged and older individuals, is the degenerative tear. These tears are associated with the natural aging process and can develop without a specific traumatic event. Magnetic resonance imaging (MRI) studies indicate that degenerative meniscal tears are present in a significant percentage of people over 50 years old, sometimes even without noticeable symptoms. This type of tear frequently affects the posterior horn of the medial meniscus, located on the inner side of the knee.
Degenerative tears often present as horizontal cleavage tears, which separate the meniscus into two distinct layers, or as complex tears involving multiple patterns and fraying. Unlike acute tears that result from a single, high-force incident, degenerative tears arise from repetitive stress on worn tissue. They are also closely linked to the progression of osteoarthritis in the knee.
Recognizing a Meniscus Tear
Individuals experiencing a meniscus tear typically report a range of symptoms, though the severity can vary based on the tear’s size and location. Pain is a common symptom, often felt along the joint line, and can worsen with activities like twisting, squatting, or going up or down stairs. Swelling and stiffness develop gradually, sometimes hours or days after the tear.
Other signs of a meniscus tear can include a popping or clicking sensation within the knee, or a feeling that the knee is catching, locking, or giving way. Doctors typically diagnose tears through a physical examination, which may involve specific maneuvers like the McMurray test to assess for pain or clicking. MRI scans are frequently used to confirm the diagnosis and provide detailed information about the tear’s type, pattern, and location. While X-rays do not show the meniscus itself, they can help rule out other potential causes of knee pain.
Treatment and Recovery
Treatment for a meniscus tear depends on its type, size, location, and the individual’s age and activity level. For many degenerative tears, non-surgical approaches are often the initial recommendation. These conservative treatments commonly include:
Rest
Ice
Compression
Elevation (RICE protocol)
Over-the-counter pain relievers, such as NSAIDs, can also help manage discomfort.
Physical therapy plays a significant role in recovery, focusing on strengthening knee muscles, improving flexibility, and restoring range of motion. For degenerative tears, physical therapy can be as effective as surgery in some cases.
If conservative measures do not provide sufficient relief or if mechanical symptoms like persistent locking occur, surgical intervention may be considered. Arthroscopy, a minimally invasive procedure, is commonly used, allowing the surgeon to either repair the torn meniscus or trim away the damaged portion in a procedure called a partial meniscectomy. Recovery times vary, with partial meniscectomy generally having a shorter recovery than meniscal repair, often allowing a return to full activity within four to six weeks.