Anterior cruciate ligament of the knee

The knee joint is one of the most complex structures of the musculoskeletal system. It is formed by the tibia, fibula and femur.

Since this joint experiences quite heavy loads, it is strengthened with connective tissue cords (ligaments) to increase stability. The anterior cruciate ligament (ACL) serves to strengthen and increase stability of the knee joint and prevents posterior and inward displacement of the tibia. The ACL is damaged quite often; the injury is characterized by partial or complete rupture of connective tissue fibers.

Causes

The main cause of knee ACL rupture is excessive force on the knee in the form of rotation on the supporting leg, in which the body and femur rotate outward while the lower leg and foot remain in one place. This mechanism of damage to the anterior cruciate ligament occurs when running, when you need to turn sharply, as well as during jumping, when the body continues to move by inertia. Most often, this type of injury occurs in athletes who engage in running, athletics, basketball, volleyball, handball, and skiing.

Also, a rupture of one ACL of the knee joint can develop when excessive mechanical force (impact) is directly applied to the anterior region of the knee. More severe damage to the anterior cruciate ligament is provoked by several factors, which include:

Treatment of degenerative changes in knee ligaments

Since degenerative changes in the cruciate ligament of the knee joint in the vast majority of cases manifest themselves as a chronic pathology, regardless of the circumstances, complex therapy, including:

Taking medications
Surgical intervention
Visioprocedures and exercise therapy,
Other measures during the rehabilitation period are prescribed exclusively by a specialized specialist.

The average treatment time until complete recovery varies widely – from 2 months to six months. For degenerative changes in the cruciate ligaments of the knee joint, surgical intervention is usually not prescribed and is indicated only in the case of stage 3 pathology.

In this case, the main indication for surgery is obvious instability of the tibia in the knee area. In the case of a partial tear or sprain of the ligaments, general treatment measures are carried out, consisting of a significant limitation of motor activity, applying a cold compress, fixing the affected area with a special bandage, as well as conservative therapy.

Conservative treatment

In the acute period of pathology, oral or injection anti-inflammatory and painkillers are prescribed. As a rule, non-steroidal anti-inflammatory drugs are used; in some cases, with very severe pain, it is rational to use narcotic analgesics.

In addition to pain relief, muscle relaxants and chondroprotectors may also be prescribed. In addition, partial or complete immobilization of the knee in particular and the leg in general is carried out, cold is applied to the affected area to reduce swelling for the first few days of the acute phase of the problem, and the use of other medications as prescribed by the doctor.

After the end of the acute period associated with degenerative changes in the crosses of the knee, complex physiotherapy procedures are prescribed in the form of magnetic therapy, electrophoresis, UHF, balneotherapy and other measures. In addition to them, the load is linearly increased in the context of introducing exercise therapy exercises, first passive, and later full-fledged.

Surgical treatment

As mentioned above, active surgical intervention is indicated only for severe forms of degenerative changes in the knee crosses, when we are talking about a complete rupture of the structures and the need for their reconstruction.

In modern practice, three main methods of carrying out such operations are used:

Closed. Plastic surgery is performed through small incisions in the localization of the cruciate ligaments with minimal invasion,
Open. Classical autoplasty with complete opening of the joint cavity and the use of semitendinosus muscles as implants,
Extra-articular operations . Performed without direct penetration of the corresponding cavity. The last type of operation is quite complicated and can be used only if the previous types of measures have had an unfavorable outcome, also in the case of a complication in the form of gonarthrosis.

In the case of surgical intervention, the main material for restoring ligaments is grafts, since direct restoration of structures by stitching does not give the necessary effect.

In this context the following applies:

Synthetic components . Mainly lavsan or nylon imitators,
Allografts. Donor natural cruciate ligaments from the knee, suitably processed and preserved. The most effective and easy to use, but there is a possibility of their rejection by the body,
Autografts. Biomaterial from the popliteal part directly from the patient, which ensures 100% survival of the installed prostheses.

Causes

Congenital decrease in the strength of connective tissue fibers of various structures of the musculoskeletal system, including the ACL.
Engaging in active or contact sports.
Anatomical features of the knee joint, in particular the width of the joint space (a wider gap is a factor in which the likelihood of ligament damage increases).
Human age – in older people, the strength and elasticity of various structures of the musculoskeletal system significantly decreases.
Gender – in women, the likelihood of ligament damage is higher than in men, which is associated with lower strength of the structures of the ligamentous apparatus, caused by the hormones estrogen and progesterone (female sex hormones).
Any knee injuries suffered in the past in which the anatomical relationship of its structures is disrupted.

Finding out the cause of ACL rupture, as well as provoking factors, will allow the doctor to select the most effective treatment, as well as preventive measures.

Symptoms and manifestations

As clinical practice shows, in most cases, degenerative changes in the cruciate ligament of the knee joint are preceded by various knee injuries of varying degrees, which were not recognized in time, or insufficiently qualified manipulations were carried out with the affected localization, for example, self-medication using traditional medicine recipes.

At the same time, until the last stage, the victim does not feel too acute pain, swelling increases gradually, the manifestations of the pathology are usually blurred and form acutely only when the problem recurs. If you suspect a complete rupture of the ligaments, you should immediately call an ambulance!

Almost always, in cases of severe types of pathology, blood flows into the cavity of the knee joint. It is accompanied by a limitation or complete absence of physical activity. The patella becomes pathologically mobile, the patient himself complains of a lack of normal support and the ability to transfer weight to the injured lower limb.

Kinds

For ease of diagnosis and prescribing adequate therapeutic tactics, all ACL ruptures are divided into several types. According to the severity of the damage, they are distinguished:

Microdamage (1st degree) – only single connective tissue fibers are torn.
Partial rupture (2nd degree) - the overall integrity of the ligament is not compromised, but a portion of the connective tissue fibers rupture.
Complete rupture (grade 3) – the integrity of the entire ligament is disrupted with a pronounced impairment of the functional state of the knee.

Also, the rupture can be isolated (only the cruciate ligament is damaged) and combined with the involvement of other structures of the knee - rupture of the posterior cruciate ligament, lateral (lateral) ligaments, meniscus tear.

Symptoms of an ACL tear

Pain in the area of injury, the intensity of which depends on the severity of the rupture.
Increased pain when trying to perform passive and active movements in the knee.
Swelling of the soft tissues of the knee area, provoked by the development of an inflammatory reaction and the release of blood plasma from the blood vessels into the intercellular substance.
Limitation of passive and active movements in the knee joint due to its instability and pain.
Instability of the knee joint, accompanied by posterior displacement of the tibia in relation to the femur.

The severity of these manifestations depends on the degree of violation of the integrity of the ligament, as well as in combination with damage to other structures of the knee. The maximum severity of clinical symptoms is determined at grade 3 rupture.

The knee joint and the role of the anterior cruciate ligament

The knee joint is not only one of the largest, but also one of the most complex joints in the human body. It is formed by the condyles (expanding ends) of the femur and tibia. Between them is the patella or kneecap, which covers the joint when it bends. The condyles of the bones are covered with smooth hyaline cartilage, making them easy to slide and, accordingly, move.

In addition, the knee joint is not congruent, that is, the bones that form it do not fit tightly together. The gaps formed between them are closed by special crescent-shaped cartilage layers - menisci. They not only act as a shock absorber, but also increase the stability of the knee joint. But the main task of ensuring the stability of this large joint lies with the group of ligaments represented by:

anterior and posterior cruciate ligaments (ACL and PCL);
tibial collateral ligament;
fibular collateral ligament.

The anterior cruciate ligament (ACL) is located directly in the center of the knee joint and protects the lower leg from excessive anterior and inward movement. It is fixed at one end to the outer condyle of the femur, and at the other to the depression on the tibia, partially intertwined with the meniscus. The PCL is located perpendicular to the ACL, thus forming a cross, which is why they got their names.

On average, the length of the ACL is 3 cm and the width is 0.7–1.2 cm.

The anterior cruciate ligament is formed by tightly interwoven collagen fibers that are almost incapable of stretching. This causes a high risk of damage to it when too much load is applied, and subsequently the development of instability of the knee joint and an increased risk of arthrosis.

The ACL has a two-bundle structure, although some authors also identify a third bundle, called the intermediate one. Traditionally, there are 2 bundles (anterointernal and posteroexternal). When the knee joint is engaged during movement, they are in a complex interaction. It is thanks to this structure that the knee joint has an optimal level of stability at any angle of flexion. In this case, the anterior cruciate ligament is almost completely devoid of blood vessels, but has nerve endings.

Of all the ligaments of the knee joint, the ACL is the most commonly injured.

Diagnostics

Arthroscopy is a diagnostic technique in which a special optical device, an arthroscope with a camera and lighting, is inserted into the joint cavity, allowing the doctor to conduct a thorough examination of its internal walls.
Ultrasound examination of the knee.
Radiography is a visualization technique that makes it possible to determine gross damage.
Computed tomography or magnetic resonance imaging, which are high-resolution techniques that allow visualization of even small violations of the integrity of the knee structures.

Using diagnostic arthroscopy using microinstruments, the doctor can perform minor surgical procedures aimed at restoring the integrity of the connective tissue fibers of the ligaments.

General recommendations

The procedure for treating degenerative changes in the knee crosses is a fairly lengthy complex event, which sometimes takes from 2 months to six months.

If you suspect a pathology, you should definitely contact a specialized traumatologist, orthopedist or surgeon.

Undergo a comprehensive examination and receive a final diagnosis, on the basis of which an individual treatment regimen will be prescribed.

In the vast majority of cases, the problem can be dealt with conservatively, also by following a number of necessary recommendations, carefully adhering to all the doctor’s prescriptions for physical therapy and exercise therapy.

However, in case of severe pathology and complete rupture of the ligaments, the only effective mechanism to combat potential complications in the short term is surgical intervention and restoration of the corresponding structures using implants.