Decoding Meniscus Tears Grades: What You Need To Know

By Paradox

Published on Jan 8, 2025

Meniscus tears are injuries to the cartilage, or meniscus, that cushions the knee joint. These tears can result from sudden twisting, direct impact, or age-related degeneration. Athletes, older adults, and individuals with physically demanding lifestyles are at greater risk for these injuries.

Meniscus tears can significantly impact daily life, causing pain, swelling, and difficulty moving the knee. Many individuals rely on medications for pain management but medications only address symptoms without treating the underlying injury. This may increase the likelihood of surgery over time.

However, parts of the meniscus have a natural blood supply, and tears in these areas may heal naturally. The Regenexx approach provides a non-surgical path to recovery utilizing advanced interventional orthobiologics to support the body’s natural healing process for those with meniscus tears. It also reduces the ongoing need for prescription medications, like opioids.

Understanding The Role Of The Meniscus In Knee Stability

The meniscus is a C-shaped piece of fibrocartilage found between the thigh bone (femur) and shin bone (tibia) in each knee.

Each knee has two menisci:

Medial meniscus: Located on the inner side of the knee, the medial meniscus is C-shaped and more rigid, helping provide knee stability.
Lateral meniscus: Found on the outer side of the knee, the lateral meniscus is more circular and flexible, allowing for a greater range of knee motion.

The Cooper classification system defines three zones of each meniscus:

Red zone: The outer edge, with a strong blood supply, offers some potential for healing.
Red-white zone: The middle section has less blood flow but still some healing capability.
White zone: The inner part lacks blood supply, making healing more difficult.

The menisci play several important roles in the knee, including:

Absorbing shock and reducing friction to protect the bones
Distributing weight evenly across the joint to improve stability
Helping stabilize the knee during movement
Lubricating the joint to ensure smooth movement

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A Closer Look At Meniscus Tears

A meniscus tear occurs when the fibrocartilage fibers are damaged or pulled apart. It can happen due to a sudden twisting motion, rapid changes of directions, or degenerative wear-and-tear of the fibrocartilage.

The symptoms of meniscus tears can vary depending on the severity of the injury. Typically, they include:

Knee pain: Without a functional meniscus, the knee loses stability, causing pain, especially along the joint. Pain tends to worsen with weight-bearing activities or bending.
Swelling: After an injury, extra blood and fluids are sent to the site as part of the body’s natural healing response. This leads to fluid accumulation and swelling.
Stiffness: Pain and swelling make movement difficult, and torn meniscus pieces may block smooth movement of the knee.
Popping sensation: A tearing sound might be heard at the time of injury, and patients might experience creaking sounds (crepitus) afterward.
Locking: Pieces of the torn meniscus can lodge in the knee joint, making it hard to move the leg fully.
Instability: A torn meniscus may make the knee feel like it could give out during daily activities.

Meniscus tears are among the most common knee problems. A 2024 study estimates that they account for half of all knee injuries.

Causes of Meniscus Tears

Meniscus tears can happen for two main reasons:

Acute injury: This occurs from sudden, forceful movements or traumatic injuries that put too much strain on the knee. Acute tears are common in sports like basketball or football, or from events like car accidents and falls.
Degenerative tear: With aging, the meniscus becomes weaker and more brittle. Over time, even minor movements or stress can cause tears. Repetitive activities such as squatting or kneeling increase the likelihood of degenerative tears by wearing down fibrocartilage.

Certain activities and conditions can increase the risk of meniscus tears. These include:

Participating in certain sports: Sports that involve fast pivots, stops, or direct impacts, such as basketball and football, put extra pressure on the knee and increase the risk of injury. A 2019 study found that a significant number of professional soccer players showed signs of meniscus injury on MRIs.
Repetitive kneeling or squatting: Activities that repeatedly put stress on the knees, such as weightlifting, can wear down the cartilage over time, leading to tears.
Obesity: Carrying extra weight puts added pressure on the knee joints. A 2023 study concluded that meniscus tears are more common among individuals with obesity.
Previous knee injuries: Past injuries, particularly to the meniscus or nearby ligaments, such as the ACL, can weaken the knee and increase the risk of future damage.
Sedentary lifestyle: Without regular exercise, the muscles supporting the knee weaken, making the joint more susceptible to injury.
Smoking: Smoking can impact cardiovascular health, affecting oxygen and blood circulation. Research suggests that reduced blood supply can hinder the cartilage’s ability to repair itself, increasing recovery times and making the meniscus more prone to injury over time.
Arthritis: Joint inflammation and damage from arthritis weaken the meniscus, making it more likely to tear.

Diagnosing Meniscus Tears

Several tests help physicians evaluate the location and severity of a tear:

Physical examination: A physician will check for symptoms like tenderness, swelling, and limited knee movement. They may move the knee in specific ways to assess pain and response.
McMurray test: This test involves bending, rotating, and straightening the knee to detect any “click” sounds or pain, which are signs of a meniscus tear.
MRI (magnetic resonance imaging): MRIs provide detailed images of soft tissues like the meniscus. Physicians use MRI results to determine the location and size of the tear and assess other knee damage. A 2021 study found MRIs to be accurate in more than 85% of cases.
X-ray: While X-rays can’t show the meniscus itself, they can help rule out other causes of knee pain, such as fractures or arthritis.
Arthroscopy: In some cases, a small camera is inserted into the knee joint through a minimally invasive procedure called arthroscopy. This allows the physician to view the tear and perform repairs if necessary.
Ultrasound. Ultrasound uses sound waves to produce images of the knee. It’s a quick, non-invasive diagnostic tool that can help visualize the meniscus and surrounding structures.

Grades Of Meniscus Tear Explained

Meniscus tears are categorized from grade 1 to grade 3 based on their severity, location, and effect on knee function. This grading system helps guide treatment decisions. The factors considered when grading meniscus tears include:

Depth of the tear: How far the tear extends through the meniscus.
Location of the tear: Whether the tear is in the red, red-white, or white zone, which impacts its healing ability.
Impact on knee stability: The more the knee’s function is affected, the higher the grade of the tear.
Type of tear: The type and location of the tear also influences grading and treatment options.
- Radial tear: Extends from the inner edge of the meniscus outward, perpendicular to the curvature.
- Horizontal tear: Runs parallel to the knee joint surface, splitting the meniscus into upper and lower sections.
- Longitudinal tear: Follows the curve of the meniscus, usually occurring in the outer third with a better blood supply.
- Bucket handle tear: A large, displaced longitudinal tear where a portion of the meniscus forms a handle-like fragment.
- Flap tear: Involves a loose piece of meniscus tissue, creating a flap that can catch in the knee joint.
- Complex tear: Combines features of multiple types of tears within the same meniscus.

Mild Grade 1 Tear

A grade 1 meniscus tear is the mildest form of meniscus injury. It typically involves a small tear in the outer layer of the meniscus, which receives a supply of blood and may be capable of healing naturally.

This type of tear doesn’t usually penetrate into the deeper fibrocartilage layers. With proper care, it also tends to remain stable.

Characteristics:

These tears are often asymptomatic and may not require medical intervention. In a 2008 study of 991 patients, 60% of those with meniscus tears did not experience symptoms like pain or stiffness.
When symptoms occur, they are usually mild and include occasional knee discomfort during activities.
Swelling is minimal, and knee function remains largely unaffected.

Treatment Options:

Non-surgical approaches: Rest, ice, and over-the-counter medications can help manage symptoms. Physical therapy may also strengthen muscles around the knee, supporting recovery.

Moderate Grade 2 Tear

A grade 2 meniscus tear penetrates deeper into the fibrocartilage but doesn’t fully split it. It usually occurs in the red-white zone, where healing is slower due to reduced blood supply. Horizontal tears that don’t reach the surface of the meniscus are also categorized as grade 2 tears.

Characteristics:

Persistent knee pain and swelling, especially during activity.
Mild stiffness, but the knee typically remains stable.

Treatment Options:

Conservative treatments: Physical therapy and rest are common approaches, though healing may take longer. If symptoms worsen or do not improve, surgical options may be considered.

Severe Grade 3 Tear

A grade 3 meniscus tear is the most severe form. It is characterized by a complete tear that often extends through the full thickness of the cartilage, splitting the meniscus into two sections. Bucket handle tears, which account for one-third of meniscus tears, are typical examples of grade 3 injuries.

These tears can occur in any part of the meniscus. However, those in the white zone (lacking blood supply) have the least potential for natural healing and may require surgical intervention.

Characteristics:

Severe knee pain, significant swelling, and frequent instability.
The knee may lock, making walking or daily activities difficult.

Treatment Options:

Surgical repair or removal: If conservative treatments fail, meniscectomy or repair may be required.

How Long Does Recovery Take For Different Grades Of Meniscus Tears?

Recovery time for meniscus tears varies depending on the severity of the tear, as well as individual factors like age, overall health, and whether additional conditions like osteoarthritis are present. The timelines below are approximations, and they may vary from one patient to another:

Grade 1: Recovery from minor tears, if accompanied by symptoms like pain and swelling, may take two to four weeks. Treatment typically includes rest, at-home care, and potentially physical therapy. However, recovery times can vary, based on individual responses to treatment.
Grade 2: Recovery from moderate tears may take four to eight weeks and often involves physical therapy or, in some cases, knee bracing. Healing time can depend on the location of the tear and how well it responds to non-surgical treatments.
Grade 3: Severe tears may require surgery, and post-surgery recovery can range from three to six months. A structured rehabilitation program is usually needed to restore knee function, strength, and stability.

These recovery timelines can be influenced by factors like the tear’s location, shape, and whether the injury occurs in a blood-rich or blood-poor area (such as the white zone). For example, moderate tears in the white zone may take longer to heal and may require more complex treatment.

Complications Associated With Untreated Meniscus Tears

Untreated meniscus tears may worsen over time and potentially lead to the following complications:

Chronic knee pain: Persistent irritation and inflammation can lead to ongoing pain, which can interfere with daily activities and lower the quality of life.
Knee instability: Without proper treatment, a torn meniscus may not support the knee effectively. This can cause instability, increasing the risk of falls or additional injuries.
Osteoarthritis: Over time, a damaged meniscus can contribute to cartilage deterioration, which may result in osteoarthritis. This condition causes pain, joint stiffness, and reduced mobility. A 2022 study suggests that untreated meniscal tears can contribute to the development or worsening of osteoarthritis.
Loss of range of motion: As the cartilage continues to break down, stiffness can develop in the knee, limiting the ability to bend or straighten the leg. This can interfere with everyday activities like walking, climbing stairs, or squatting.

Treatment Options For Meniscus Tears

Treatment for meniscus tears is based on the severity of the tear and includes both non-surgical and surgical methods:

Rest: Resting the knee, combined with techniques like icing, compression, and elevation, can help reduce strain on the joint and prevent further injury. This is often the first line of treatment for traumatic meniscal tears or minor to moderate injuries.

However, some research may indicate that prolonged icing can slow down healing by reducing blood flow to the injured area. Additionally, long-term rest or immobilization can weaken the muscles around the knee.

A 2024 study suggests that immobilization can cause older adults to lose up to 10% of their muscle mass in seven days. Physical therapy may be necessary to restore function.

Physical therapy: Guided exercises help strengthen the muscles around the knee, improving stability and flexibility. Physical therapy may also include ultrasound or electrical stimulation techniques to support healing. It is commonly used for grades 1 and 2 tears, and as part of rehabilitation after surgery.
Medication: Nonsteroidal anti-inflammatory drugs (NSAIDs) can help manage pain and inflammation temporarily, improving mobility in the short term. However, they do not address the underlying cause of pain and do not contribute to healing. Prolonged use can lead to side effects like heart disease, kidney damage, or stomach ulcers.
Surgical options: Severe tears, particularly those located in the white zone (where there is limited blood supply), may require surgery. Surgical procedures include:
- Meniscectomy: The removal of the damaged part of the meniscus.
- Meniscus repair: The surgical stitching of the tear.

Surgical interventions, even minimally invasive ones like arthroscopy, carry risks such as infection, blood clotting, or failure of the repair. A 2022 study noted that about 36% of meniscus repairs fail within two years of surgery, indicating the need for careful consideration of treatment options.

Studies published in 2020 and 2023 have suggested that the outcomes of meniscectomy may be similar to those achieved through placebo surgeries or conservative treatments, indicating that surgery may not always be necessary.

Additionally, undergoing surgery for meniscus tears may be linked to an increased risk of developing osteoarthritis (OA). 2023 research indicates that meniscectomy is linked to higher rates of OA compared to meniscus repair.

A 2018 study shows that, even in patients who underwent meniscus repairs, the rates of OA consultations with a physician were two times higher compared to the general population.

The Regenexx Approach For Meniscus Tears

Regenexx injectates support the treatment of meniscus tears through interventional orthobiologics, which promotes the body’s ability to heal naturally. This approach provides an alternative to conventional treatments by potentially reducing the need for surgery or prescription medications.

Physicians in the licensed Regenexx network customize treatment plans that may include one or more of the orthobiologics below.

Regenexx-SD Injectate

Procedures using Regenexx-SD injectate include a patented protocol that utilizes Bone Marrow Concentrate (BMC) which contains the patient’s own mesenchymal stem cells. The cell processing for a Regenexx-SD injectate routinely achieves 20x concentration— above what non-Regenexx cell processing can achieve.

Regenexx-SCP Injectate

Procedures using Regenexx-SCP injectate represent a supercharged version of platelet-rich plasma (PRP). In this process, blood is drawn, then processed to isolate the platelets and growth factors. The growth factors are then purified, concentrated, and injected into the knee area using imaging guidance for precision. Regenexx-SCP injectate provides a higher concentration of growth factors compared to typical PRP procedures.

Regenexx-PL Injectate

Procedures using Regenexx-PL injectate are a highly specialized derivative of platelet-rich plasma (PRP) with a faster and more concentrated release of growth factors compared to typical PRP. The PL injectate is often combined with other orthobiologics such as PRP and bone marrow concentrate.

Supporting Your Meniscus Health Without Surgery

Regenexx offers a patented protocol to reduce pain and improve mobility by enhancing the body’s natural healing abilities through interventional orthobiologics. This may help reduce the need for meniscus tear surgery and reduce the need for prescription drugs.