Torn Meniscus: Symptoms, Types, Causes and Treatment

A torn meniscus is one of the most common knee injuries, affecting everyone from athletes to older adults with no apparent trauma. This condition can cause significant pain, limit your mobility, and, if left untreated, may contribute to the early development of osteoarthritis. In this comprehensive article, we'll guide you through the symptoms, types, causes, and the latest evidence-based treatments for a torn meniscus, drawing from current research and expert consensus.

Symptoms of Torn Meniscus

When the meniscus in your knee is torn, it doesn't always announce itself dramatically. While some experience sudden pain, others may have subtle or slowly developing symptoms that can be mistaken for other knee issues. Understanding the typical signs can help with early recognition and timely management.

Symptom	Description	Typical Presentation	Source(s)
Pain	Aching or sharp discomfort in the knee	Often at joint line	2 4
Swelling	Fluid accumulation in the knee	Hours to days after injury	2 8
Clicking	Sensation or sound of clicking/pop	With movement or squatting	2 3
Locking	Knee gets stuck or cannot fully extend	Intermittent, mechanical	2 6
Tenderness	Sensitivity along the joint line	On physical palpation	2
Instability	Feeling of knee “giving way”	During activity or walking	8

Table 1: Key Symptoms

Pain and Tenderness

Pain is the most common and often the first symptom. It can be sharp, especially during twisting or squatting, or dull and persistent. Tenderness along the knee’s joint line—where the meniscus sits—is typical and can be detected during a physical exam 2 4.

Swelling and Stiffness

Swelling may develop within hours or days after the injury, especially in more acute or traumatic tears. Sometimes, the knee feels stiff and less mobile, making it hard to bend or straighten completely 2 8.

Mechanical Symptoms: Clicking, Locking, and Instability

Mechanical symptoms set meniscus tears apart from other knee injuries. You might notice:

• Clicking or popping when moving the knee
• Locking, where the knee temporarily cannot move through its full range
• A feeling of instability or the knee "giving way," particularly during pivoting or walking on uneven surfaces 2 3 6 8

Subtle Presentations

Degenerative tears, more common in middle-aged and older adults, may cause milder, insidious symptoms that come on gradually. These can be mistaken for general joint aging or early arthritis and may delay diagnosis 2.

Types of Torn Meniscus

Understanding the different types of meniscus tears is vital for diagnosis and treatment decisions. Tears can be classified by their pattern, location, and whether they are traumatic or degenerative.

Type	Description	Common Patient Group	Source(s)
Traumatic	Sudden, acute tear from injury	Young, active individuals	4 6 8
Degenerative	Slow, wear-and-tear breakdown	Middle-aged/older adults	2 3 4 8
Radial	Tear that slices across the meniscus	All ages, often missed on MRI	2 3
Horizontal	Tear splits meniscus into upper/lower layers	Degenerative, young athletes	2 4 8
Flap	Loose, mobile fragment	Degenerative or traumatic	2 3
Longitudinal	Tear runs parallel to the meniscus rim	Often traumatic	2 8
Complex	Combination of patterns	Older adults, advanced OA	3 4

Table 2: Types of Meniscus Tears

Traumatic vs. Degenerative Tears

Traumatic tears occur suddenly, often during sports or accidents involving twisting or direct impact. These are typically seen in younger, active individuals and tend to have more acute symptoms. Traumatic tears are often of the longitudinal or vertical type 4 6 8.

Degenerative tears develop over time due to chronic stress and aging. They are more common in middle-aged or older adults and frequently present with complex, horizontal, or flap patterns. Symptoms are often milder and may be mistaken for early arthritis 2 3 4 8.

Tear Patterns and Morphology

• Radial tears: These cut across the meniscus and can be especially problematic, as they disrupt the meniscus’s load-bearing function. They are often underdiagnosed on MRI and are associated with the progression of osteoarthritis 2 3.
• Horizontal and Flap tears: Common in degenerative cases, these split the meniscus or create a loose piece that can catch in the joint 2 4.
• Longitudinal and Bucket Handle tears: These run along the rim; if large, they can cause the knee to lock. Repair is often possible, especially if the tear is in the vascularized "red zone" 8 10.
• Complex tears: Involve multiple patterns and are usually seen in older adults or those with advanced joint degeneration 3 4.

Classification Systems

The International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine (ISAKOS) classification considers tear depth, length, location, and tissue quality. This helps surgeons tailor treatment to individual patients 7.

Causes of Torn Meniscus

A torn meniscus can result from a single traumatic event or from gradual degeneration over time. Understanding the underlying causes is key for prevention and management.

Cause	Mechanism	Typical Group	Source(s)
Acute Trauma	Sudden twisting, pivoting, or impact	Athletes, young adults	4 6 8
Degeneration	Age-related wear and tear	Middle-aged/older adults	2 3 4 8
Mucoid Degeneration	Intrasubstance changes leading to tearing	Younger individuals, rare	2
Osteoarthritis	Associated joint degeneration	Older adults	1 3
Structural Variant	Discoid meniscus prone to tearing	All ages, congenital	1 2

Table 3: Common Causes

Acute Traumatic Causes

Most traumatic meniscus tears occur during activities that involve twisting or pivoting on a bent knee, such as in sports like soccer, basketball, or skiing. A forceful direct impact can also cause tears. Traumatic tears are characterized by an acute onset of symptoms and are often associated with other knee injuries such as ACL tears 4 6 8.

Degenerative Changes

With aging, the meniscus becomes less flexible and more brittle, making it susceptible to tears from relatively minor stress or even without any clear injury. Degenerative tears are especially common in people over 40 and may be the first sign of underlying osteoarthritis 2 3 4 8.

Special Considerations: Mucoid and Discoid Meniscus

• Mucoid degeneration is a rare cause, often affecting younger patients. It involves abnormal substance changes within the meniscus, leading to tears without a history of trauma. The clinical presentation is often insidious, which can delay diagnosis 2.
• Discoid meniscus is a congenital variant where the meniscus is abnormally shaped, making it more prone to tearing. Adults with a discoid meniscus are more likely to have coexisting degenerative changes, such as cartilage lesions and osteophyte formation 1 2.

Osteoarthritis and Meniscus Tears

Meniscal tears are both a cause and a consequence of knee osteoarthritis. Certain tear patterns, like posterior root or radial tears, are closely linked to cartilage loss and joint degeneration 1 3.

Treatment of Torn Meniscus

Modern treatment of meniscal tears has shifted dramatically from simply removing the damaged tissue to preserving and repairing the meniscus whenever possible. The approach depends on the type, location, and cause of the tear, as well as patient-specific factors.

Treatment	Indication	Key Considerations	Source(s)
Non-operative	Degenerative, minor, or stable tears	First-line for most degenerative	7 8
Meniscus Repair	Traumatic, repairable tears (esp. young)	Best in vascular zones; preserves cartilage	6 7 8 10
Meniscectomy	Irreparable or mechanical symptoms	Increased risk of OA long-term	7 8 9
Biological Augmentation	Enhancing repair in select cases	PRP, tissue adhesives, matrix wraps	9 10
Rehabilitation	All cases	Essential for recovery	8

Table 4: Treatment Options

Non-operative Management

For degenerative meniscal tears or minor injuries, non-operative treatment—including physical therapy, pain management, and activity modification—is recommended as the first line. Recent studies show that surgery offers little benefit over conservative care for many degenerative tears 7 8.

• Physical therapy focuses on strengthening muscles around the knee and improving joint function.
• Non-steroidal anti-inflammatory drugs (NSAIDs) can help with pain.
• Activity modification and weight management reduce knee stress.

Meniscus Repair

When possible, especially in younger patients with traumatic tears, meniscus repair is favored over removal. Repair is most successful for tears in the peripheral, vascularized "red zone." Preservation helps prevent the early onset of osteoarthritis 6 7 8 10.

• Repair techniques include suturing the torn edges together.
• Early surgery is preferred for traumatic tears.
• The slogan "Save the Meniscus" reflects the strong push toward preservation 7 8 9.

Meniscectomy

Partial removal (meniscectomy) may be necessary for irreparable tears or when significant mechanical symptoms persist after conservative treatment. However, this approach increases the risk of developing osteoarthritis in the long term and should be considered only after other options have been exhausted 7 8 9.

• Indicated for persistent locking or pain unresponsive to other treatments.
• The extent of removal should be minimized.

Biological Augmentation and Advanced Techniques

Newer strategies aim to enhance meniscus healing, especially in cases where standard repair is challenging:

• Platelet-rich plasma (PRP) injections: Deliver growth factors to the repair site.
• Matrix wraps and tissue adhesives: Provide scaffolding for repair.
• Trephination, synovial rasping: Stimulate blood flow to promote healing 9 10.

These are promising but require further research to establish their effectiveness in daily clinical practice.

Rehabilitation

Regardless of the treatment method, rehabilitation is crucial. Tailored exercise programs restore knee function, prevent stiffness, and protect the repair or healing meniscus 8.

Conclusion

A torn meniscus can disrupt daily life, but modern understanding and treatment strategies have vastly improved outcomes. Key takeaways include:

• Symptoms: Look for joint line pain, swelling, mechanical symptoms (clicking, locking), and instability.
• Types: Tears may be traumatic or degenerative, with various patterns (radial, horizontal, longitudinal, etc.).
• Causes: Trauma, degeneration, congenital variants, and underlying joint disease can all contribute.
• Treatment: Early emphasis is on non-operative care or meniscus repair. Meniscectomy is reserved for specific cases. Emerging biological augmentation techniques may further improve healing.

Remember: Saving the meniscus is now the guiding principle—preservation and repair are prioritized to maintain joint health and function.