Meniscal tear


The knee is the largest joint in the body.

The meniscus is a fibrocartilaginous structure within the knee joint, consisting of the medial and lateral semi circular components that transfer load and joint stability.

Meniscal tears are separation of fibrous structure and can be classified as traumatic or degenerative.

Tears can also be defined based on pattern and location which can influence healing.

A Swedish population study showed an annual incidence of 79 per 100,000 persons.

Acute traumatic tears are more prevalent in active young populations, engaging in sports, and it is often accompanied by cruciate ligament injuries.

Degenerative tears typically affect older adults, and commonly found in patients with knee osteoarthritis:63% of older adults with symptomatic osteoarthritis had an MRI diagnosis of a meniscus tear.

Incidental meniscal tears on imaging is common with a study showing  19% of adults, age 40 years or older without any pain or injury, having an asymptomatic meniscal tear on MRI.

Systematic use of MRI is not indicated in first line assessment of meniscal, tears, particularly in middle aged in older adults.

Cartilage within the knee joint helps protect the joint from the stresses placed on it from walking, running, climbing, and bending.

The medial and lateral menisci are two large C-shaped cartilages that are positioned on the top of the tibia.

A torn meniscus occurs because of trauma caused by forceful twisting or hyper-flexing of the knee joint.

Participants in playing pivoting sports is associated with a higher prevalence of traumatic meniscal tears compared with not engaging in sports.

Metaanalysis indicate high prevalence of symptomatic degenerative, meniscal, tears in older populations, male sex, work related kneeling, and squatting, walking more than 2 miles, a day, lifting or carrying more than  10 kg, at least 10 times a week, participants in climbing more than 30 stairs per day,.

May occur as part of a degenerative process of the knee joint and occurs in up to 60% of individuals older than 50 years of age without knee pain.

Symptoms of a torn meniscus include knee pain, swelling, popping, and giving way.

Meniscal tears typically present with knee pain localized to the joint line and an accompanying effusion.

Acute onset often follows a noncontact, twisting/rotary injury for traumatic tears, or insidious onset for degenerative tears.

Mechanical symptoms, such as kneeclicking, and catching, locking have a modest sensitivity and specificity and predictive value for meniscal tear.

To diagnose a meniscus tear by provocation of symptoms, includes the McMurray test and joint line tenderness.

Treatment of a torn meniscus may include observation and physical therapy with muscle strengthening to stabilize the knee joint.

When conservative measures are ineffective treatment may include surgery to repair or remove the damaged cartilage.

The quadriceps and hamstring muscles are responsible for moving the knee joint.

When the quadriceps muscles contract, the knee extends or straightens.

The hamstring muscles, located on the back of the thigh, are responsible for flexing or bending the knee.

These muscles stabilize the knee and preventing it from being pushed in directions.

There are four ligaments that stabilize the knee joint at rest and during movement: the medical and lateral collateral ligaments (MCL, LCL) and the anterior and posterior cruciate ligaments (ACL, PCL).

The medial and lateral meniscus are two thicker wedge-shaped pads of cartilage attached to top of the tibia, the tibial plateau.

Each meniscus is curved in a C-shape, with the front part of the cartilage called the anterior horn and the back part called the posterior horn.

There is an articular cartilage that lines the joint surfaces of the bones within the knee, including the tibia, femur, and patella.

Torn knee cartilage refers to damage to one of the C-shaped menisci of the knee between the femur and tibia.

When the meniscus is damaged, irritation occurs.

The knee joint is no longer smooth, pain can occur with each flexion or extension.

Can be damaged because of a single event or it can gradually wear out because of age and overuse.

A torn meniscus is damage to the cartilage that is positioned on top of the tibia and allows the femur to glide when the knee joint moves.

Such tears described by where they are located anatomically in the C shape and by their appearance.

An MRI or knee arthroscopy, can locate the specific part of the cartilage anatomy that is torn and its appearance.

The blood supply is different to each part of the meniscus.

The better the blood supply, the better the potential for recovery.

The outside rim of cartilage has better blood supply than the central part of the “C.”

Blood supply to knee cartilage also decreases with age.

Up to 20% of normal blood supply is lost by age 40.

A forceful twist or sudden stop trauma can cause the end of the femur to grind into the top of the tibia, pinching and potentially tearing the cartilage of the meniscus.

This injury can also occur with deep squatting or kneeling, especially when lifting a heavy weight.

Often occur during athletic activities, especially in contact sports like football and hockey.

Motions that require pivoting and sudden stops, in sports like tennis, basketball, and golf, can also cause meniscus damage.

The risk increases with age because cartilage begins to gradually wear out, losing its blood supply and its resilience.

Increasing body weight also puts more stress on the meniscus.

Daily activities like walking and climbing stairs increase wear, degeneration, and tearing.

It is estimated that six out of 10 patients older than 65 years have a degenerative meniscus tear.

Many of these tears may never cause problems.

Some of the fibers of the cartilage are interconnected with those of the ligaments that surround the knee.

Meniscus injuries may be associated with tears of the collateral and cruciate ligaments, depending upon the mechanism of injury.

Some with a torn meniscus know exactly when they hurt their knee with acute onset of pain.

Patients may actually hear or feel a pop in their knee.

Among patients with nonobstructive meniscal tears physical therapy is noninferior to arthroscopic partial meniscectomy for improving patient knee function over 24 month follow-up (ESCAPE).

Results in an inflammatory response, including pain and swelling.

Fluid accumulation within the knee joint may make it difficult and painful to fully extend or straighten the knee.

In some situations there may not be an acute injury, but the knee cartilage may become damaged as a consequence of aging arthritis and degeneration or wearing away of the meniscus.

The initial inflammatory response resolves, however, other symptoms may develop over time and include: Pain with running or walking, intermittent swelling of the knee joint, popping sensation when climbing up or down stairs, buckling, and locking.

By inspecting,palpating, and applying specific diagnostic maneuvers, one may often make the diagnosis of a torn meniscus.

Palpating the joint for warmth and areas of tenderness, assessing the stability of the ligaments, and testing the range of motion of the knee joint and the power of the quadriceps and hamstring muscles.

The McMurray test: flexing the knee and rotating the tibia while feeling along the joint.

The McMurray test is positive for a potential tear if a click is felt.

Magnetic resonance imaging confirms the diagnosis of a torn meniscus.

A knee MRI can visualize the inner structures of the knee, including the cartilage and ligaments, the surface of the bones, and the muscles and tendons that surround the knee joint.

By knowing the anatomy the surgeon can plan a potential operation and alternative treatments.

Plain X-rays cannot identify meniscal tears.

Plain X-rays may indicate the presence of bony changes, including fractures, arthritis, and loose bony fragments within the joint.

X-rays of both knees while the patient is standing, allows the joint spaces to be compared to assess the degree of cartilage wear.

Plain X-rays may also uncover other causes of knee pain, including arthritis and pseudogout.

Arthroscopy previous to MRI was used to confirm the diagnosis, and had added benefit that the injury may be repaired at the same time.

Treatment of a meniscus tear depends on its severity, its location, and underlying disease within the knee joint.

Often it is treated conservatively using anti-inflammatory medications and physical therapy rehabilitation to strengthen muscles around the knee to prevent joint instability.

In athletes or in patients whose work is physically demanding may require immediate surgery.

The treatment decision to treat conservatively or with an operation is an individualized one.

Acute injury is treated with rest, ice, compression and elevation, and anti-inflammatory medications, may help relieve pain and inflammation

A brace may hold the knee in full extension and this can worsen the pain by decreasing the space within the knee joint capable of accommodating any fluid or swelling.

Physical therapy is helpful, to strengthen the muscles surrounding the knee adding stability of the joint, as is maintaining an ideal body weight, while shoe orthotics may be useful to distribute the forces generated by walking and running.

Exercise therapy can be as effective as surgery for some individuals without osteoarthritis having a meniscal tear knee injury. ((Kise NJ)

Every year at a cost of a few billion dollars, around 2 million people around the world have knee arthroscopy.

Existing evidence shows that knee surgery provides little benefit for the majority of individuals.

If conservative therapy fails, surgery may be an option.

Knee arthroscopy allows assessment of the cartilage tear and potentially repair it.

The goal of surgery is to preserve as much cartilage as possible.

Surgical options include: meniscus repair, sewing the torn edges together or meniscectomy, trimming away the torn area, and smoothing the injury site.

Microfracture surgery by drilling into the surface of the bone can stimulate articular cartilage development.

The articular cartilage that grows as a result of microfracture surgery, is not as thick or as strong as the original meniscus cartilage.

Exercise and muscle strengthening can protect the joint and maintain range of motion.

Anti-inflammatory medications may be considered to decrease swelling and pain arising from the knee joint.

Knee injections with corticosteroids or hyaluronan preparations may be used to decrease joint inflammation and to bring temporary symptom relief that can last weeks or months.

Joint replacement may be an option for patients who have substantial degeneration of the knee with worn out cartilage.

With meniscal injuries, if the knee is stable and if the symptoms do not persist and do not limit lifestyle, nonsurgical treatments remain an option.

In a randomized trial of physical therapy versus arthroscopic partial menisectomy: The mean function score improved by 26.2 points in the arthroscopic partial meniscectomy group and by 20.4 points in the physical therapy group.
These findings suggest noninferiority of either choice and that a trial of conservative management using physical therapy  in patients  with degenerative meniscal tears is justified.
Studies comparing arthroscopy versus physical therapy have yielded mixed results.

It is suggested that patients that have significant osteoarthritis with non-displaced meniscus degeneration do not benefit from the arthroscopy.

The decision to defer surgery depends upon whether the knee joint remains functional and allows the patient to participate in their preferred activities.

There is no evidence that surgical management is superior to rehabilitation-based approaches for most traumatic and degenerative, meniscal tears.

Most patients with a symptomatic meniscal tear should have physical therapy for three months or longer as first line treatment.

With conservative management the pain and swelling of a torn meniscus should resolve within a few days.

For degenerative  meniscal, tears, exercise therapy is the first line treatment, with few additional benefits from surgery.

Nonoperative management for 4-6 weeks is appropriate for most patients with simple traumatic and degenerative tears.

80 to 87% of athletes return to pre-injury sports competition, following meniscus surgery.

Recovery, rehabilitation and strengthening the muscles surrounding the knee to promote joint stability are goals.

Maintaining an ideal body weight, and avoiding activities that cause pain are recommended.

If knee arthroscopy is performed, rehabilitation goal is to return range of motion to the knee as soon as possible, to increase the strength of the muscles surrounding the knee, return range of motion to normal, and promote and preserve stability of the joint.

Physical therapy is an important part of the surgery process.

Rehabilitation prior to the procedure with strengthening exercises for the quadriceps and hamstring muscles prevents muscle weakness that may occur immediately after an operation.

Most patients return to mild routine activity in less than six weeks.

For meniscectomy, where the damaged cartilage is surgically removed, the rate of complication is less than 2%, and includes anesthetic complications, infection, and failure to prevent long-term stiffness, swelling, and recurrent pain.

For meniscus repair, complications occur in up to one-third of patients.

Common in older patients without knee pain as well as in patients with symptomatic osteoarthritis of the knee.

Common in active participants in sports that require cutting and pivoting.

Meniscal injuries most common surgically treated knee condition.

Estimated 850,000 meniscus surgeries annually.

The medial meniscus is on the inner part of the knee, while the lateral meniscus is on the outer part.

Medial meniscus torn more often than lateral meniscus.

Men suffer with more tears than women.

Often related to twisting or hyper flexion injuries.

Squatting and rotational manipulations reproduce symptoms.

Young individuals typically sustain injury via athletic activities while older patients tear their meniscus during less vigorous activities.

Aging associated with meniscus degeneration and trivial trauma can result in a tear.

Large number of elderly have asymptomatic meniscal tears.

It is estimated that six out of 10 patients older than 65 years have a degenerative meniscus tear.

Quadriceps strengthening exercises help reduce swelling and restores normal muscle control to an injured knee.

Diagnosed via history and physical exams.

Significantly more common in patients with symptomatic osteoarthritis of the knee and are correlated with a higher grade of radiographic changes.

Found on a radiograph or magnetic resonance imaging study does not reliably predict clinical symptoms.

MRI confirms the diagnosis.

Symptoms include recurrent joint effusion and swelling of the knee, popping sounds, catching and locking symptoms and pain with squatting.

Pain typically located on one side of the knee, with medial meniscus pain on the inside and lateral meniscus pain on the outside of the knee.

Patients with such an injury have trouble in athletic endeavors to cut or pivot.

Symptoms include recurrent joint effusion and swelling of the knee, popping sounds, catching and locking symptoms and pain with squatting.

Pain typically located on one side of the knee, with medial meniscus pain on the inside and lateral meniscus pain on the outside of the knee.

Repair is most commonly done arthroscopically.

Goal of surgical repair is to preserve as much meniscal tissue as possible, since arthritis develops more quickly in patients with the least meniscus remaining.

In the young and, if located near the edge of the meniscus where the best blood supply is, the tear is often repairable.

Lesions near the central surface and those in older patients are often removed by a partial meniscectomy because they lack the ability to heal.

In selected cases a cadaver meniscal transplant can be done to prevent joint degeneration.

Partial meniscectomy are usually performed arthroscopically.

Partial meniscectomy are usually followed by improved symptoms and rapid healing

Meniscal repairs are usually performed on patients under the age of 40 years with a tear near the outer rim of the meniscus.

The goal of repair is to preserve meniscal tissue and the procedure is indicated only if healing can be expected.

Meniscal transplantation or allograft may be indicated in lateral avascular lesions in young athletes, with partial lateral meniscectomy, and who are developing early degenerative changes.

Meniscal repair performed concurrently with anterior cruciate ligament reconstruction for acutely injured knees.

Repaired menisci involved the peripheral one-third of the meniscus most commonly.

There is a 14 percent meniscal repair failure rate.

Medial repairs fail earlier than lateral repairs ― failing after 2.1 years while lateral repairs typically failed after around 3.7 years.

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