A torn meniscus is a common knee injury that can cause significant long-term problems if not addressed. The meniscus is a C-shaped piece of tough, rubbery fibrocartilage located between the thighbone and the shinbone. Its primary functions are to act as a shock absorber, helping to distribute the body’s weight evenly across the joint, and to provide stability to the knee. When this structure is compromised by a tear, its ability to perform these functions is immediately reduced, setting the stage for a progressive cascade of deterioration within the entire knee joint.
Worsening Pain and Mechanical Symptoms
When a meniscal tear is left untreated, the damaged fragment is constantly subjected to the forces of walking, running, and twisting motions. This continuous load and friction prevent the torn edges from healing and often cause the tear to enlarge or propagate. This physical degradation leads to the development of pronounced mechanical symptoms in the knee.
The loose flap of cartilage can get caught between the bones during movement, resulting in a sudden, sharp pain and swelling. This can manifest as the knee “catching” or, in more severe cases, “locking,” where the joint becomes mechanically blocked and unable to fully straighten. Persistent discomfort and swelling limit the range of motion, which in turn can lead to muscle weakness around the joint.
Instability and Damage to Other Knee Structures
The meniscus plays a significant role in maintaining the smooth movement and alignment of the knee joint. A torn meniscus, particularly one involving the root attachments, compromises this structural integrity, leading to instability. Patients may describe a sensation of the knee “giving way” or buckling under their weight, especially when pivoting or stepping on uneven ground.
This instability introduces excessive friction and shear forces throughout the joint. This excessive wear begins to damage the articular cartilage that covers the ends of the femur and tibia. Articular cartilage has no capacity for self-repair, and its degradation is a serious complication. The abnormal forces can also stress surrounding soft tissues, potentially increasing the risk of secondary injuries to ligaments.
Long-Term Risk of Severe Arthritis
The most severe long-term consequence of an untreated meniscal tear is the accelerated onset of osteoarthritis (OA). The meniscus normally absorbs between 40% and 70% of the load transmitted across the knee joint. When this shock-absorbing function is lost, the direct pressure on the articular cartilage exponentially increases.
This sustained high pressure causes the irreversible breakdown of the articular cartilage, which defines osteoarthritis. The loss of this smooth gliding surface leads to bone-on-bone contact, chronic pain, stiffness, and severely limited mobility. Meniscal damage significantly increases the likelihood of developing OA. Once the joint reaches this stage of deterioration, the damage is permanent and frequently necessitates a total knee replacement surgery.
Future Limitations on Repair
Delaying treatment for a meniscal tear can severely restrict the available options for surgical intervention. When a tear is addressed early, particularly within the first few weeks or months, a surgeon can often perform a meniscal repair, which involves suturing the torn edges back together. The goal of this procedure is to preserve the entire piece of fibrocartilage to maintain its function.
However, if the tear is neglected, the torn fragment often becomes too frayed, displaced, or non-viable due to chronic mechanical wear and lack of blood supply. In these chronic cases, the tissue is no longer healthy enough to heal, making a full repair technically impossible.
The only surgical option left is typically a meniscectomy, which is the removal of the damaged piece of the cartilage. While a meniscectomy relieves mechanical symptoms like locking, the removal of meniscal tissue further reduces the joint’s shock absorption capacity, thereby compounding the risk of accelerated osteoarthritis that the untreated tear had already initiated.