The knee joint, a complex structure, contains two crescent-shaped pieces of cartilage known as menisci. Positioned between the thigh bone (femur) and shin bone (tibia), these menisci act as shock absorbers, distributing weight and cushioning the joint during movement. They also contribute to the knee’s overall stability and provide a smooth surface for the bones to glide. Individuals who have experienced a meniscus tear often worry about re-injury.
The Likelihood of a Meniscus Retear
A meniscus can retear, even after surgical repair. Reteas are not uncommon, with reported failure rates for modern meniscus repairs ranging from approximately 10% to 40%. For instance, a 2020 study noted that 36% of medial meniscus surgeries required a repeat repair or partial removal after five or more years. While meniscal repair aims to preserve cartilage and promote long-term knee health, it carries a higher reoperation rate compared to partial meniscectomy, where only the torn portion is removed.
A comprehensive review found an overall failure rate of 19.5% for modern meniscus repairs over five years. Another analysis of patients who underwent meniscus repair alongside an ACL reconstruction reported an overall failure rate approaching 40%. While repair is often preferred for its long-term benefits, a subsequent tear remains possible.
Factors Contributing to a Retear
Several factors can influence the likelihood of a meniscus retear. Initial tear type and surgical method play a role; for example, medial meniscus repairs tend to have higher reoperation rates than lateral meniscus repairs. Meniscal repairs performed concurrently with an anterior cruciate ligament (ACL) reconstruction often show a lower failure rate compared to isolated repairs. A complete meniscus tear has also been associated with a higher retear risk.
Activity level and age can also contribute to retear risk. As people age, meniscus tissue naturally loses elasticity and strength, making it more susceptible to tears. However, some research suggests age may not directly correlate with a higher retear risk after repair, with younger, highly active individuals sometimes facing greater risk due to continued strenuous activities.
Adhering to rehabilitation protocols is important; failing to follow post-surgical guidelines can compromise healing and increase re-injury risk. Biomechanical factors, such as muscle strength imbalances around the knee, can alter load distribution across the joint, placing increased stress on the repaired meniscus. This stress can make the knee vulnerable to further damage, particularly during twisting or pivoting movements.
What to Do if You Suspect a Retear
Recognizing the signs of a potential meniscus retear is important for timely intervention. Common symptoms include:
Renewed pain in the knee, especially along the joint line
Swelling that might develop hours or days after an incident
Stiffness
Mechanical symptoms such as a popping or crunching sensation
Catching or locking of the knee
A feeling of instability or weakness
Difficulty bending or fully straightening the knee
If a retear is suspected, professional medical evaluation is advisable. A healthcare provider will perform a physical examination of the knee, checking for tenderness, range of motion, and conducting specific tests like the McMurray test. Imaging tests, such as X-rays, can rule out other causes of knee pain. A Magnetic Resonance Imaging (MRI) scan is often used to visualize the meniscus and confirm a tear. In some cases, knee arthroscopy, a minimally invasive surgical procedure, may be used for a definitive diagnosis.
Treatment considerations for a retear depend on its location, size, and overall health and activity goals. Non-surgical approaches, including rest, ice, compression, and elevation (RICE method), and pain relief medications, may be recommended for less severe cases. Physical therapy is a key part of recovery, focusing on strengthening knee-supporting muscles and restoring full range of motion. If conservative measures are insufficient, surgical options, such as another repair or partial meniscectomy, might be considered.
Preventing future re-injuries involves a multi-faceted approach. Consistent adherence to a rehabilitation program is important for building strength and stability around the knee. Strengthening core and leg muscles, including quadriceps, hamstrings, and calves, helps reduce stress on the meniscus. Incorporating dynamic stretching before activity and ensuring proper warm-up and cool-down routines can prepare the knee for physical demands. Listening to the body’s signals, avoiding activities that cause pain, and gradually increasing exercise intensity are beneficial strategies.