Meniscus injury and ligament strain?

In life, judging from the shape and position of the meniscus, to put it simply, the meniscus has the function of stabilizing the knee joint and promoting nutrition inside the joint. It is precisely because of the stabilizing effect of the meniscus that the human knee joint can be protected from injury during exercise. However, most people cannot distinguish between meniscus injury and ligament strain. So how do you judge between meniscus injury and ligament strain yourself?

01Preliminary judgment

Overextension test

When the knee joint is fully straightened and slightly hyperextended, the ruptured meniscus is pulled or squeezed, causing severe pain.

Overbend test

When the knee joint is extremely flexed, the ruptured posterior horn becomes stuck and causes severe pain.

Meniscus rotation test

The patient lies on his back with the affected hip and knee fully flexed. The examiner places one hand on the outer space of the joint for palpation and holds the heel with the other hand to perform a large range of calf rotation. The internal rotation test is for the lateral meniscus, and the external rotation test is for the medial meniscus. While maintaining the rotated position, the knee joint is gradually extended to 90 degrees, and attention is paid to the joint angle when the sound occurs. If a sound is felt when the joint is fully flexed, it indicates damage to the posterior horn of the meniscus. If a sound is felt when the joint is extended to about 90 degrees, it indicates damage to the body. Then, while maintaining the rotated position, the joint is gradually extended to a slightly flexed position (Mouche test). At this time, a sound is felt and this indicates possible damage to the anterior horn of the meniscus.

Grinding test

The patient lies prone with the knee bent to 90 degrees. The examiner presses the calf down forcefully and performs internal and external rotation movements to cause friction between the femoral and tibial articular surfaces. If external rotation causes pain, it indicates a lateral meniscus injury. Thereafter, the calf is lifted and internal and external rotation movements are performed. If external rotation causes pain, it indicates a medial collateral ligament injury. This test has certain practical significance in examining the meniscus of patients with hip ankylosis.

Squat-walk test

It is mainly used to check whether the posterior horn of the meniscus is damaged. The method is as follows: ask the patient to squat and walk in a duck step, changing direction from time to time, either left or right. If the patient can complete these movements well, damage to the posterior horn of the meniscus can be ruled out. If the knee joint cannot be fully flexed due to pain, and there is a sound and knee pain and discomfort when squatting and walking, it is a positive result. In cases of posterior horn rupture of the meniscus, the sound is very obvious when squatting and walking. This test is only suitable for examining adolescent patients, especially for checking whether the meniscus is damaged during large-scale physical examinations.

02Auxiliary examination

X-ray

Anteroposterior and lateral radiographs of the knee joint are of great significance for differential diagnosis, and can rule out osteochondral injuries, intra-articular loose bodies, bone tumors, etc. They are also important in deciding whether to undergo surgery. For example, arthroscopic surgery is generally not suitable for patients with severe osteoarthritis.

CT

Its role in the diagnosis of meniscus tears is limited and its accuracy is low, so it has been replaced by MRI examination. Meniscal tears appear as changes in morphology and density on CT. One or more irregular linear low-density areas appear at the tear site.

MRI

When a linear high signal appears in the meniscus and reaches its free edge or articular surface, it can be diagnosed as a meniscus tear. According to the relationship between the degree of abnormal signal changes in the meniscus and pathological changes, the different degrees and morphological abnormalities of meniscus degeneration and tearing in MRI images can be divided into three levels of signals. Usually, grade 3 signal changes can be seen pathologically as fibrocartilage breaks. Therefore, if grade 3 signals are seen on a fragment of the meniscus accompanied by irregular shape, it can be diagnosed as a meniscus tear.

It must be noted that no single test is the sole basis for diagnosing meniscus injury of the knee. The final diagnosis should be made based on a combination of clinical symptoms, tender points, and various positive test results. The imaging examination of meniscus injury is mainly MRI, which can reach 90%.

Differential diagnosis of ligament sprain:

1. Ligament rupture: This is usually caused by movements beyond the range of joint movement during activities, which leads to passive pulling of the relevant ligaments and causes tearing or complete rupture. Ligament ruptures are often accompanied by sprains and fractures.

2. Ligament sprain: Ligament sprain refers to damage to the soft tissues of the limb joints or body (such as muscles, tendons, ligaments, blood vessels, etc.) without fractures, dislocations, skin and flesh damage, etc. The main clinical manifestations are pain and swelling at the injured site and limited joint movement, which often occur in the waist, ankle, knee, shoulder, wrist, elbow and hip.

3. Ligament contusion: This is usually caused by movements beyond the range of joint movement during activities. The degree of ligament injury is not serious, but redness and swelling will occur.

After a joint ligament is sprained, there will be local swelling, pain, tenderness, and if there is subcutaneous bleeding, a cyanotic area may be seen. It is very important to treat joint ligament sprains correctly in the early stages. Because ligament tissue is not easy to regenerate and recover, if it is not treated properly or misdiagnosed and turns into a chronic disease, it may leave functional impairment and be prone to sprain again in the future. After an acute injury occurs, activity should be stopped immediately to reduce bleeding. Immediately flush the injured area with cold water or apply ice to the affected area to stop the bleeding. Then cover with a bandage and apply pressure to prevent swelling. If the ligament is completely ruptured or a fracture is suspected, a doctor must be asked for further examination and treatment after the pressure bandage. After 24 to 48 hours, the internal bleeding at the injured site has stopped. At this time, you can use a warm towel for hot compresses or massage to reduce swelling and promote blood absorption. When applying warm compresses, the temperature should not be too high, the time should not be too long, and the massage should not be too heavy, so as not to aggravate exudation, edema or rebleeding. In order to promote the recovery of joint function, attention should be paid to the combination of movement and stillness, and early activities should be carried out without feeling pain. After basic recovery, strength exercises should be done on the muscles around the joints to improve the relative stability of the joints.