What is a Meniscus Injury?
A meniscus injury refers to a tear or damage to the meniscus, a C-shaped fibrocartilage structure located between the femur (thigh bone) and tibia (shin bone) in the knee joint. The menisci act as shock absorbers, distributing weight and stabilizing the knee during movement. Each knee contains two menisci:
- Medial meniscus – located on the inner side of the knee, more prone to injury due to its firm attachment to the joint capsule.
- Lateral meniscus – located on the outer side of the knee, more mobile and less frequently injured.
Meniscus injuries can occur due to acute trauma or degenerative changes. Traumatic tears are common in athletes, while degenerative tears develop over time due to cartilage wear and aging.
Biomechanics of Meniscus Injury
The menisci play a crucial role in load distribution, joint stability, and shock absorption. During movement, they adapt to changes in knee position, allowing for smooth articulation between bones.
A meniscus tear commonly results from a combination of rotational force and axial compression. This occurs when the foot is planted while the knee twists or undergoes a sudden forceful rotation. Pivoting, squatting, or landing from a jump can create excessive pressure on the meniscus, leading to injury.
Meniscus injuries are classified based on tear pattern and location:
- Radial tears – extending from the inner edge outward, affecting weight distribution.
- Bucket-handle tears – causing a large displaced fragment, leading to knee locking.
- Flap tears – creating loose cartilage that catches during movement.
- Degenerative tears – progressive wear-related damage, common in older individuals.
Healing potential depends on the tear’s location. The outer third (“red zone”) has better blood supply, increasing healing potential, while the inner two-thirds (“white zone”) is poorly vascularized, often requiring surgical intervention.
Incidence
Meniscus injuries are one of the most common knee injuries, with an estimated incidence of 61 per 100,000 people annually. They frequently occur in sports involving twisting, pivoting, and sudden directional changes such as soccer, basketball, and skiing.
The elderly population is at increased risk due to degenerative meniscus tears, which develop as cartilage weakens with age. Studies indicate that up to 60% of individuals over 65 years old may have asymptomatic meniscus tears detected on MRI.
Meniscus tears are also frequently associated with ACL (anterior cruciate ligament) injuries, with up to 50% of ACL tears involving concurrent meniscus damage.
Risk Factors
Several factors contribute to an increased risk of meniscus injuries.
Sports and High-Impact Activities
Athletes in high-impact sports that require pivoting, cutting, and jumping (e.g., football, tennis, rugby, and gymnastics) are at higher risk. These activities place excessive rotational stress on the knee joint, increasing the likelihood of meniscus damage.
Age and Degeneration
With aging, cartilage weakens, making the meniscus more prone to tears. Individuals over 40 years old often experience degenerative meniscus injuries, even without significant trauma. These injuries are more difficult to heal, as the inner portion of the meniscus has limited blood supply.
Previous Knee Injuries
A history of knee injuries, particularly ACL ruptures and knee instability, increases the risk of a secondary meniscus tear. When knee ligaments are compromised, joint mechanics become unstable, leading to increased stress on the menisci.
Occupational and Lifestyle Factors
Jobs requiring frequent kneeling, squatting, or heavy lifting (e.g., construction work, carpentry, and farming) increase the risk of meniscus injuries due to repetitive knee stress. On the other hand, a sedentary lifestyle weakens the muscles supporting the knee, making it more vulnerable to injury.
Obesity
Excess body weight places additional stress on the knee joint, increasing the risk of cartilage breakdown and meniscus tears. Every extra kilogram of body weight exerts four times the force on the knee, accelerating degenerative changes.
Symptoms
Meniscus injuries present a wide range of symptoms, depending on the severity and location of the tear.
Knee Pain
Pain is one of the most common symptoms of a meniscus injury. It is usually localized to the affected side (medial or lateral) and worsens with movement, particularly during squatting, climbing stairs, or prolonged standing.
Swelling and Stiffness
A meniscus tear often triggers inflammation, leading to swelling that develops gradually over hours. The accumulation of fluid within the knee joint causes stiffness, restricting movement and making it difficult to fully extend or bend the knee.
Locking or Catching Sensation
If a torn meniscus displaces within the joint, it can cause a locking or catching sensation. The knee may suddenly “lock” in a bent position, requiring manual assistance to straighten. This symptom is more common in large tears, such as bucket-handle tears.
Reduced Range of Motion
Meniscus injuries often lead to limited knee mobility, making daily activities such as walking, kneeling, or prolonged sitting difficult. Individuals with severe tears may struggle to fully extend the knee, resulting in a persistent feeling of tightness.
Instability and Weakness
A torn meniscus can compromise knee stability, leading to a feeling of the knee “giving way”. This is particularly problematic for athletes, as knee instability increases the risk of further joint damage.
Meniscus injuries can range from mild discomfort to severe dysfunction, and proper diagnosis and treatment are essential to prevent long-term complications.
Diagnosis
Clinical Examination
The diagnosis of a meniscus injury begins with a thorough clinical examination. A healthcare professional assesses the knee through inspection, palpation, and range of motion testing to identify pain, swelling, or mechanical symptoms such as locking or catching. Several clinical tests help determine the presence of a meniscus tear, including:
- McMurray Test – A passive flexion and rotation maneuver that detects pain or clicking, indicating a possible meniscal tear.
- Apley’s Compression Test – The patient lies prone, and the examiner applies downward pressure while rotating the tibia; pain suggests meniscus damage.
- Thessaly Test – The patient stands on the affected leg, bends the knee to 20 degrees, and rotates the body; pain or instability may indicate a tear.
While these tests help identify a meniscus injury, imaging studies are necessary for a definitive diagnosis.
Patient History and Symptoms
A detailed patient history provides crucial insights into how the injury occurred. Key factors include:
- Mechanism of injury – A twisting motion with weight-bearing often suggests a meniscal tear.
- Onset of symptoms – Acute injuries typically involve immediate pain and swelling, whereas degenerative tears present gradually.
- Functional limitations – Patients may report difficulty bending the knee, locking, or a feeling of instability.
Imaging Studies
Magnetic Resonance Imaging (MRI) is the gold standard for diagnosing meniscus injuries. MRI has a sensitivity of 93% and specificity of 88% for detecting meniscal tears. This imaging technique provides detailed visualization of soft tissues, allowing differentiation between acute traumatic tears and degenerative changes.
X-rays are often performed to rule out fractures or osteoarthritis, although they do not directly visualize meniscal damage. In cases where MRI is not available or contraindicated, ultrasound may be used as an alternative, although it is less reliable.
Treatment
Meniscus injury treatment depends on several factors, including tear type, location, severity, and patient activity level. Options range from conservative management to surgical intervention in cases where symptoms persist.
Conservative Treatment
Non-surgical management is often the first-line approach for minor tears or degenerative meniscus injuries. It includes:
- Rest and activity modification – Avoiding activities that exacerbate symptoms.
- Ice application – Reducing swelling and pain.
- NSAIDs (Non-Steroidal Anti-Inflammatory Drugs) – Controlling pain and inflammation.
- Physical therapy – Strengthening the quadriceps, hamstrings, and hip muscles to enhance knee stability.
Surgery
When is Surgery Necessary?
Surgical intervention is considered when:
- Symptoms persist despite conservative treatment.
- The tear is large, displaced, or causing mechanical symptoms (e.g., locking).
- The patient is an athlete or highly active individual requiring optimal knee function.
- The injury involves a repairable portion of the meniscus (red zone).
Types of Meniscus Surgery
Arthroscopic Partial Meniscectomy
In cases where the meniscus tear is irreparable, a partial meniscectomy is performed. This procedure involves removing the damaged portion of the meniscus, preserving as much healthy tissue as possible.
- Procedure – A minimally invasive arthroscopy is performed, using small incisions and specialized instruments. The surgeon trims the torn portion, smooths the remaining meniscus, and removes any loose fragments.
- Recovery – Patients typically experience reduced pain within weeks and can return to normal activities within 4-6 weeks. However, meniscectomy increases the risk of osteoarthritis due to reduced shock absorption (Chahla et al., 2019, Springer).
Meniscus Repair
A meniscus repair is preferred when the tear is located in the outer “red zone”, where healing potential is higher due to better blood supply.
- Procedure – The torn meniscus is sutured together rather than removed, promoting natural healing.
- Recovery – Meniscus repair requires a longer recovery period than meniscectomy. Patients typically undergo 6-8 weeks of limited weight-bearing, followed by several months of physical therapy. Return to sports may take 4-6 months, but outcomes are more favorable in the long term (Bram et al., 2024, PubMed).
Meniscus Transplant
In rare cases where the entire meniscus is removed, a meniscus transplant may be considered. This procedure involves implanting donor meniscus tissue to restore shock absorption and joint function.
- Indications – Young, active patients with previous total meniscectomy and persistent pain.
- Recovery – 6-12 months, depending on graft integration and rehabilitation progress.
Recovery After Meniscus Surgery
Recovery time varies based on the type of surgery performed.
- Partial meniscectomy – Most patients return to normal activities within 4-6 weeks.
- Meniscus repair – 4-6 months, with gradual reintroduction of weight-bearing and strengthening exercises.
- Meniscus transplant – Up to a year, requiring strict post-operative rehabilitation.
Rehabilitation includes:
- Phase 1 (Weeks 1-4) – Pain management, swelling reduction, and gentle mobility exercises.
- Phase 2 (Weeks 4-8) – Progressive strengthening, weight-bearing exercises, and balance training.
- Phase 3 (Months 3-6) – Functional movement training, sport-specific drills, and gradual return to full activity.
The long-term prognosis depends on tear type, surgical outcome, and adherence to rehabilitation protocols.
Conservative Treatment Methods
Physical Therapy
Physical therapy may help improve knee stability, reduce pain, and restore function following a meniscus injury. A trained physiotherapist can develop a rehabilitation program focusing on muscle strengthening, joint mobility, and neuromuscular control. Some of the techniques that may be beneficial include:
- Manual therapy – Gentle mobilization techniques may help reduce stiffness and improve joint movement.
- Soft tissue therapy – Massage techniques may aid in reducing muscle tension and promoting circulation.
- Electrotherapy – Modalities such as TENS (Transcutaneous Electrical Nerve Stimulation) and ultrasound might help alleviate pain and promote tissue healing.
Kinesiotherapy
Kinesiotherapy, or movement therapy, focuses on gradual strengthening of the muscles around the knee while improving stability and function. The goal is to reduce excessive stress on the meniscus and support the joint. Exercises that may help include:
- Quadriceps strengthening – Leg raises and isometric contractions may help stabilize the knee.
- Hamstring activation – Bridges and hamstring curls might improve posterior knee support.
- Proprioception training – Balance exercises on an unstable surface may help restore neuromuscular control.
- Stretching – Gentle quadriceps, hamstring, and calf stretching could prevent excessive joint strain.
Bracing and Support
Using a knee brace may help stabilize the joint and limit excessive movement that can aggravate symptoms. Functional braces are designed to provide additional support during daily activities or sports participation.
Medications and Pain Management
Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) such as ibuprofen or naproxen may help manage pain and swelling. However, prolonged use should be discussed with a healthcare provider.
Injection Therapy
In some cases, corticosteroid injections may be considered to reduce inflammation, though they do not heal the meniscus. Platelet-Rich Plasma (PRP) injections have also been explored for meniscus injuries, with some studies suggesting they might aid in tissue repair (Bram et al., 2024, PubMed).
How Can I Help Myself?
Meniscus injuries can vary in severity, and self-care strategies may help manage symptoms. It is important to consult a medical professional before attempting any treatments.
Rest and Activity Modification
Avoiding excessive strain on the knee and modifying daily activities may help prevent further damage. Reducing activities that require deep squatting, twisting, or jumping may be beneficial.
Cold Therapy
Applying ice packs for 15-20 minutes every few hours may help reduce swelling and pain. Using a compression wrap may also support the knee joint.
Strength and Mobility Exercises
Engaging in low-impact exercises, such as stationary cycling or swimming, might help maintain knee function without excessive stress. Gentle strengthening and stretching routines may also support recovery.
Maintaining a Healthy Weight
Excess body weight increases pressure on the knee joint, which may accelerate cartilage breakdown. A balanced diet and regular low-impact exercise may contribute to joint health.
Supplements and Nutrition
Certain dietary supplements, such as glucosamine and chondroitin, are often promoted for joint health. However, evidence regarding their effectiveness remains mixed. Omega-3 fatty acids and anti-inflammatory diets might contribute to overall joint function (Chahla et al., 2019, Springer).
Frequently Asked Questions
Can a meniscus tear heal on its own?
Small tears in the outer “red zone” of the meniscus may heal on their own due to better blood supply, while larger or inner-zone tears often require medical intervention.
How long does it take to recover from a meniscus injury?
Recovery time depends on the severity of the tear and treatment method. Minor injuries may improve within a few weeks, whereas surgical recovery can take 4-6 months.
What exercises should I avoid with a meniscus tear?
Movements that involve deep squats, twisting motions, and high-impact jumping should generally be avoided, as they can worsen the injury.
Is surgery always necessary for a meniscus tear?
Not all meniscus injuries require surgery. Conservative treatment may be effective, especially for minor or degenerative tears. However, if symptoms persist, surgery might be recommended.
Can I continue playing sports with a meniscus tear?
Returning to sports depends on pain levels, knee stability, and treatment response. Athletes are usually advised to complete rehabilitation before resuming full activity.
