Meniscal Injury: Types, Symptoms and Treatment Options

The knee is one of the most complex, stressed and fascinating joints in the human body, a biomechanical masterpiece that allows us to walk, run, jump and perform countless daily activities. At the center of this delicate structural balance are the menisci, two small but fundamental fibrocartilaginous structures. When addressing the topic of meniscus injury causes types and therapeutic options represent the fundamental pillars for understanding this pathology in depth, which turns out to be one of the most widespread orthopedic problems globally. Whether dealing with a young athlete at the peak of their competitive career or an older individual coping with natural joint aging processes, the rupture of the meniscus is a clinical event that requires precise framing, accurate diagnosis and a meticulous rehabilitation pathway. In this article, we will explore in depth and scientifically every aspect related to meniscal injuries, from their etiology to the most modern strategies of physiotherapy and rehabilitation.

Anatomy and Biomechanics: The Crucial Role of the Menisci

To fully understand the dynamics of an injury, it is essential to start from anatomy. In each knee there are two menisci: the medial meniscus (located in the inner part of the knee) and the lateral meniscus (located in the outer part). They are interposed between the femoral condyles and the tibial plateaus.

For a complete overview, see the comprehensive guide to knee pain.

The medial meniscus has a “C” shape and is intimately connected to the joint capsule and the medial collateral ligament, which makes it less mobile and, consequently, statistically more prone to injury than its counterpart. The lateral meniscus, instead, has a more closed shape, almost like an “O”, and is more mobile, managing to better accommodate the rotational movements of the knee.

The functions of the menisci are multiple and vital for joint health:
Shock absorption: They act as true shock absorbers. During walking or running, body weight is transmitted through the knee; the menisci distribute this load (the so-called shear forces or hoop stresses*) over a larger surface area, protecting the underlying articular cartilage from premature wear.

• Joint stability: They increase congruence between the spherical surfaces of the femoral condyles and the flat surfaces of the tibial plateaus, functioning as stabilizing wedges.
• Lubrication and nutrition: They contribute to distributing synovial fluid within the joint, nourishing the hyaline cartilage, which is devoid of blood vessels.
• Proprioception: They contain nerve endings that send information to the brain about knee position and movement.

A clinically fundamental aspect concerns the vascularization of the meniscus. Only the peripheral third of the meniscus (the so-called “red-red zone”) receives direct blood supply from the genicular arteries. The intermediate zone (“red-white zone”) has poor vascularization, while the innermost third (“white-white zone”) is completely avascular and nourishes only by diffusion from synovial fluid. This anatomical distinction is crucial: an injury in the peripheral zone has excellent chances of healing spontaneously or through surgical suture, while an injury in the inner zone has no capacity for autonomous healing.

Causes of Meniscal Injuries

Menisci are C- and O-shaped cartilage discs between femur and tibia that absorb shock, stabilize the knee, and facilitate proprioception through their distinct vascular zones. Meniscal injuries are not all the same and etiology can vary drastically based on patient age, level of physical activity and past clinical history. Causes can be divided into two main macro-categories: traumatic and degenerative.

Traumatic Causes

Traumatic injuries typically occur in young, active or athletic subjects. The classic injury mechanism involves sudden knee torsion while the foot is firmly anchored to the ground and the joint is in partial flexion. This movement generates extreme shear forces that exceed the resistance of fibrocartilaginous tissue, causing laceration.
Sports that involve sudden direction changes, jumps and physical contact are those at highest risk. Among these, soccer, basketball, volleyball, skiing, rugby and tennis stand out. In many cases, traumatic meniscal injury does not occur in isolation, but is accompanied by damage to other structures, such as rupture of the Anterior Cruciate Ligament (ACL) and injury of the Medial Collateral Ligament, configuring the clinical picture known as O’Donoghue’s “unhappy triad”.

Degenerative Causes

With advancing age, meniscal tissue undergoes a natural aging process: it loses water, becomes less elastic, more rigid and fragile. In these conditions, violent trauma is not necessary to cause rupture. Degenerative injuries are typically found in individuals over 40-50 years and can be caused by mundane daily movements, such as squatting to pick up an object, rising abruptly from a low chair or making a slight twist to get out of the car.
These injuries are often associated with initial or established knee arthritis (gonarthrosis), where cartilage and meniscal deterioration proceed in parallel, feeding each other in an inflammatory vicious cycle.

Types of Meniscal Injury

Morphological classification of the injury is determining for establishing the most appropriate therapeutic approach. Injuries can assume different geometric forms within the meniscal structure:

• Longitudinal Tear: Follows the curved axis of the meniscus. If it occurs in the vascularized peripheral zone, it has excellent healing chances if sutured.
• Bucket-handle Tear: This is an extensive longitudinal tear where the inner fragment detaches and flips inside the joint, just like a bucket handle. This condition often causes mechanical knee locking (“locked knee”), preventing complete extension, and represents a relative orthopedic emergency.
• Radial Tear: Starts from the free inner margin (avascular) and heads toward the periphery. Since it interrupts the circumferential fibers of the meniscus, it severely compromises its load-absorbing capacity.
• Flap Tear: A piece of meniscus tears forming a mobile flap that can get caught between joint surfaces during movement, causing acute pain and clicking sensation.
• Horizontal Tear (or cleavage): Divides the meniscus into upper and lower halves. It’s typical of degenerative processes and can lead to meniscal cyst formation, due to synovial fluid being pumped inside the fissure.
• Complex Tear: Presents a combination of multiple rupture planes (radial, horizontal, longitudinal) and is characteristic of severely degenerated knees or those subjected to very high-energy trauma.

Main Symptoms: How to Recognize an Injury

The symptomatological picture of a meniscal injury can vary considerably depending on the type of rupture, its location and clinical phase (acute or chronic). However, there are cardinal signs and symptoms that should raise suspicion of this type of pathology:

• Pain: This is the most common symptom. In traumatic injuries, pain is acute and immediate, often precisely localized on the medial or lateral joint line (the point where femur and tibia meet). In degenerative injuries, pain may be dull, intermittent and gradually worsen over time, exacerbating under load or during twisting movements.
• Swelling (Edema and Effusion): Unlike cruciate ligament ruptures, which cause immediate hemorrhagic swelling (hemarthrosis), swelling from isolated meniscal injury tends to develop slowly, often 12-24 hours after the traumatic event. The knee appears swollen due to reactive synovial fluid accumulation.
• Joint Locking: As mentioned for bucket-handle tears, a meniscal fragment can get caught between condyles, physically preventing the knee from straightening or bending completely.
• Clicks, Snaps and Crepitus: During flexion-extension movement, it’s possible to feel or hear joint sounds, caused by the femoral condyle passing over the torn meniscal flap.
• Giving Way Sensation: The patient may feel that the knee “gives out” or doesn’t support weight, a symptom due to reflex inhibition of the quadriceps muscle caused by pain, or mechanical interference from the torn fragment.
• Range of Motion (ROM) Limitation: Difficulty fully bending the knee (e.g. squatting) or extending it completely.

Diagnostic Pathway: From Clinical to Imaging

An accurate diagnosis is the result of careful combination of medical history, clinical objective examination and instrumental investigations.

Clinical Examination and Orthopedic Tests

Clinical examination begins with knee observation (looking for swelling, muscle atrophy), palpation (searching for exquisite pain on the joint line) and range of motion assessment. Subsequently, the healthcare professional performs specific provocative tests, designed to stress the meniscus and reproduce symptoms:

• McMurray Test: The patient is supine. The examiner flexes the knee and rotates it internally and externally while extending it. A palpable or audible “click” associated with pain indicates injury.
• Apley Test: The patient is prone with knee flexed at 90 degrees. The examiner applies downward pressure on the sole of the foot while rotating the tibia. Pain suggests meniscal damage.
• Thessaly Test: The patient stands on one leg on the knee to be examined, flexed at 20 degrees. The patient performs trunk rotations. This is considered one of the most reliable clinical tests for reproducing torsional loading pain.

Instrumental Examinations

While clinical assessment is fundamental, imaging is necessary to confirm diagnosis and plan treatment.
Magnetic Resonance Imaging (MRI): Represents the absolute Gold Standard*. It allows extremely clear visualization of soft tissues, identifying not only the presence of injury, but also its type, extent, location and the state of surrounding cartilage and ligaments.

• X-ray: Doesn’t show menisci, but is essential, especially in patients over 40, to rule out bone fractures, assess limb alignment and, most importantly, quantify the degree of joint wear (arthritis) and joint space narrowing.
• Ultrasound: Has limited utility for diagnosing deep meniscal injuries, but can be useful for identifying peripheral meniscal cysts or quantifying joint effusion.

Therapeutic Approach: Conservative vs Surgical Treatment

Management of a meniscal injury has undergone profound evolution in recent decades. In the past, the tendency was to remove the entire injured meniscus (total meniscectomy). However, long-term studies have unequivocally demonstrated that meniscal removal leads to rapid and inexorable arthritic degeneration of the knee. Today, the orthopedic and rehabilitation paradigm is to “save the meniscus” whenever possible.

The choice between conservative (non-surgical) and surgical treatment depends on multiple factors: patient age, activity level, type and location of injury, presence of mechanical symptoms (locking) and diagnostic timeliness.

Conservative Treatment

This is the first-line intervention for degenerative injuries, small stable peripheral injuries and patients who don’t present joint locking. Conservative treatment is based on:

• Acute Phase (POLICE Protocol): Protection, Optimal Load, Ice, Compression and Elevation. The goal is to reduce inflammation and pain.
• Pharmacological Therapy: Use of NSAIDs (Non-Steroidal Anti-Inflammatory Drugs) prescribed by physician to control pain symptoms.
• Physiotherapy and Rehabilitation: This is the heart of conservative treatment. A knee with an injured meniscus needs strong and reactive musculature to compensate for the loss of cushioning.

When is Surgery Indicated?

Surgical intervention, usually performed arthroscopically (a minimally invasive technique), is indicated in case of:

• Acute traumatic injuries in young and athletic patients.
• Bucket-handle tears with joint locking.
• Conservative treatment failure after 2-3 months of well-conducted physiotherapy.

The main surgical options are two:

• Meniscal Suture: When the injury is in the vascularized zone (red-red), the surgeon applies sutures to repair the tissue. Recovery times are longer, but the meniscus is saved, preserving future knee health.
• Selective (or Partial) Meniscectomy: If the injury is in the avascular zone and cannot heal, the surgeon removes only the unstable and lacerated fragment, regularizing margins and preserving the greatest possible amount of healthy meniscal tissue.

The Fundamental Role of Physiotherapy

Whether opting for conservative treatment or facing surgical intervention, physiotherapy is indispensable for ensuring full functional recovery. The rehabilitation pathway must be personalized and guided by a professional, proceeding through progressive phases based on respect for biological tissue healing times.

Phases of Rehabilitation

• Phase 1: Pain and inflammation control. Use of instrumental physical therapies (such as Tecar therapy, high-power Laser therapy, Cryotherapy) and cautious passive mobilization to avoid joint stiffness development.
• Phase 2: Range of motion (ROM) recovery. Active and passive exercises to restore complete knee flexion and extension. Complete extension is priority for correct ambulation.
• Phase 3: Muscle strengthening. The quadriceps muscle (particularly the Vastus Medialis Obliquus) tends to atrophy rapidly after knee trauma. Strengthening must involve not only the quadriceps, but also the hamstrings (flexors), glutes and calf muscles, to ensure global lower limb stability. Initially, closed kinetic chain exercises (where the foot is weight-bearing) are preferred to reduce shear forces on the knee.
• Phase 4: Proprioception and neuromotor control. Exercises on unstable surfaces (Freeman boards, proprioceptive cushions) to re-educate joint receptors and improve knee balance and reactivity to external stimuli.
• Phase 5: Return to sport (Return to Play). For athletes, this phase involves introduction of sport-specific technical gestures (jumps, direction changes, sprints) in controlled environment, before returning to competition.

Recommended Therapeutic Exercises

Below are some fundamental exercises that compose a typical rehabilitation program. Warning: execution of these exercises must always be previously authorized and supervised by your doctor or physical therapist, to adapt them to the specific clinical condition.

Initial Phase (Mobility and Activation)

• Quadriceps Isometric Contractions: Seated or supine with leg straight. Push the back of the knee toward the floor contracting the thigh muscle. Hold contraction for 5-10 seconds and release. Repeat 15-20 times. This exercise reactivates the muscle without moving the joint.
• Heel Slides: Supine. Slowly slide the heel toward the buttocks bending the knee as far as pain allows, then straighten the leg again. Repeat 15 times. Helps recover flexion.
• Straight Leg Raise: Supine, with healthy leg bent and injured leg straight. Contract the quadriceps of the straight leg and lift it about 30-40 cm from the ground. Hold 3 seconds and lower slowly. Repeat 15 times.

Intermediate Phase (Strengthening)

• Mini-Squat: Standing, back against a wall or holding a chair for balance. Feet shoulder-width apart. Bend knees descending about 30-40 degrees (no further), keeping weight on heels and ensuring knees don’t go past toes. Rise contracting glutes. 3 sets of 12 repetitions.
• Glute Bridge: Supine, knees bent and feet on ground. Lift pelvis upward strongly contracting glutes and posterior thigh muscles, until forming a straight line between shoulders, pelvis and knees. Hold 5 seconds and lower. 3 sets of 15 repetitions.
• Abduction Strengthening: Lying on healthy side. Lift injured leg upward keeping it straight and in line with torso. 3 sets of 15 repetitions. Strengthens gluteus medius, fundamental for pelvis and knee stability.

Advanced Phase (Proprioception and Loading)

• Single-leg Balance: Balance only on injured leg, keeping knee slightly unlocked (not hyperextended). Hold position for 30-60 seconds. To increase difficulty, close eyes or perform exercise on soft cushion.
• Forward Lunges: Take a step forward and bend both knees to 90 degrees. Front knee should not go past toes. Return to starting position with decisive push. 3 sets of 10 repetitions per leg.

Prevention: How to Protect the Knees

While it’s not possible to prevent every single trauma, there are proven effective strategies to significantly reduce the risk of meniscal injury, both traumatic and degenerative:

• Maintain adequate body weight: Excess weight is the number one enemy of weight-bearing joints. Every excess kilogram multiplies by 3 or 4 times at knee level during walking and running, accelerating meniscal and cartilage wear.
• Muscle conditioning: Maintaining good muscle tone, with correct balance between quadriceps and hamstrings, provides an active protective “brace” to the knee, absorbing forces that would otherwise discharge on the menisci.
• Warm-up and Stretching: Before any sports activity, it’s vital to perform dynamic warm-up to prepare tissues for effort, improving their vascularization and elasticity.
• Adequate footwear: Use shoes appropriate for the type of sport and playing surface. Worn or inadequate shoes alter lower limb biomechanics, increasing knee stress.
• Sports technique: In situational sports, training correct landing technique from jumps and direction changes is fundamental to avoid dangerous twisting.

Frequently Asked Questions (FAQ)