What Is a Torn Lateral Meniscus?

Rupture of semilunar fibrocartilage in the knee joint. The tear is mainly caused by the torsional force in the knee flexion or full flexion, which is usually a football injury. It is also common in people working in squatting positions, such as coal miners. Medial meniscus tears are more common than lateral meniscus tears, which is related to the anatomic characteristics of the meniscus.

Rupture of semilunar fibrocartilage in the knee joint. The tear is mainly caused by the torsional force in the knee flexion or full flexion, which is usually a football injury. It is also common in people working in squatting positions, such as coal miners. Medial meniscus tears are more common than lateral meniscus tears, which is related to the anatomic characteristics of the meniscus.

Western Medicine Name

Torn meniscus

Chinese Medicine Name

Osteoporosis

Affiliated Department

Surgery-Orthopedics

Disease site

Knee joint, cartilage

The main symptoms

Pain, limited mobility

Main cause

Strenuous exercise, such as: basketball player

Multiple groups

Young and middle-aged

Contagious

Non-contagious

Meniscal tear 1. Causes and common diseases:

The medial meniscus is larger and more stable. The meniscus is tightly attached to the medial collateral ligament, which is vulnerable to injury. The lateral meniscus is small, with large variations in size and shape. Separated, so it is not easy to be damaged due to its high mobility. Knee meniscus tears and cartilage injuries are common causes of knee pain, and are the most common and representative of mechanical knee diseases.

Meniscal tear 2. Differential diagnosis:

Can be divided into chronic degenerative laceration or acute traumatic laceration.

The former is related to aging and recurrent chronic injury. Histological manifestations are mucoid degeneration, including increased glycosaminoglycan matrix, chondrocyte necrosis, fibril separation, and microcyst formation. As the course of the disease progresses, fibrocartilage separates and breaks, forming horizontal dissections along the direction of collagen fibers, and when it extends to the articular surface, a meniscus tear is formed.

The latter is caused by sports injuries and is more common in young people. The damage mechanism is related to sudden rotation of joints and vigorous movement. Sudden rotation of the femur causes the meniscus to move to the center and cause a tear in the edge. Violent flexion and extension causes the posterior angle of the meniscus and the body to squeeze between the tibial joints and cause tearing.

Meniscal tears are divided into 5 categories: longitudinal tears; horizontal tears; oblique tears; radial tears; others, including petal tears, composite tears, and tears of meniscus metamorphosis. .

Meniscal tear 3. Inspection:

(1) General clinical examination:

Knee joint fixation tenderness, passive hyperextension and flexion test, McMurray test, abrasion test (Apley test), rocking test, Helfet test, squat test.

(Two) magnetic resonance imaging (MRI):

It has the advantages of non-invasiveness, sensitivity, specificity and high resolution. Before arthroscopic diagnosis and treatment, MRI diagnosis of knee meniscus injury can provide important reference for clinicians before surgery, avoid unnecessary trauma, and have significant clinical value. .

Meniscal tear 4. Principles of treatment:

Incomplete meniscus tears or small (5 mm), stable edge tears (meaning that the center of the torn meniscus is not more than 3 mm from the edge of the complete meniscus, and the length of the tear is not more than 1 cm vertically, Longitudinal tear), the knee joint is stable, and non-surgical treatment can achieve good results. For non-surgical treatment, cast from groin to ankle or knee brace for 4 to 6 weeks. After 4 ~ 6 weeks, stop braking and strengthen the functional exercises of the muscles around the knee and hip joints.

If symptoms recur after a period of non-surgical treatment, meniscectomy or repair surgery is needed.

(1) Partial meniscectomy:

That is, only free and unstable meniscus fragments are removed. Examples are bucket handle tears, removable medial edges, petal-shaped tears, or oblique tears. During meniscal partial resection, stable, balanced, and healthy meniscus peripheral tissues are retained.

(B) Subtotal meniscectomy:

Due to the type and extent of the tear, part of the meniscus periphery needs to be removed. This condition is common in compound tears or degenerative tears in the posterior horn of the meniscus. When removing the affected part, it must be cut to the periphery of the meniscus and include part of the periphery. The so-called "sub-full" is because in most cases the anterior horn and middle 1/3 of the meniscus are retained.

(3) Total meniscectomy:

When the meniscus is detached from its peripheral synovial attachment site, and the lesions and tears in the meniscus are extensive, a total meniscectomy is required; if the meniscus body separated from the surrounding parts can be salvaged, it is not necessary to perform a full resection Surgery should be considered for meniscus suture.