The knee joint is the largest in the human body. And it is clear that the mechanics of his movements and anatomy will be a match. For students of medical universities there is nothing more complicated than arthrosindesmology, that is, the science of joints. The crown of complexity is the knee joint. And before talking about his diseases, you should first understand the structure.
Bones
The formation of the joint is based on two long bones - the femur and tibia - and one small, patella. Contrary to popular belief, the fibula does not participate in the knee joint. She has a joint with the tibia just below. At the lower edge of the tibia there are two elevations called condyles. They represent the upper part of the joint, and are covered with cartilage. On the opposite side, the tibia has a plateau that ideally fits the condyles. It is also covered with cartilage for better gliding. The last flat bone - the patella - is located between the condyles in a specially formed recess. All bones involved in the joint are covered with
hyaline cartilage up to five millimeters thick. It is dense, shiny and very smooth. Its function is to soften the load during the execution of movements and reduce friction between the bones. On top of this entire structure is covered with a connective tissue capsule.
Ligaments
In order to combine the three bones together, one cartilage is not enough. A good fixing device is required, which will be both flexible, resilient and durable. This function is performed by ligaments. They are formed from dense connective tissue and stretched between the bones.
So, on the lateral surfaces of the joint are collateral ligaments that strengthen the capsule. There are two of them: lateral and medial. The function of these cords is to limit the mobility of the joint to the side. There are also ligaments inside the capsule. They are located between the articular surfaces and are called cruciform. Their task is to prevent the joint from moving excessively back and forth. The anterior cruciate ligament of the knee joint begins on the tibia. She anticipates her forward movement and slipping out of the articular surface. The posterior cruciate ligament of the knee joint also begins on the tibia and inhibits its backward movement in relation to the femur.
Together they help to keep the joint in a state of balance, provide stability and smooth movements.
Menisci
Outwardly, they look like ligaments, but in structure are more similar to cartilage. They are located in the middle between the tibia and femur and are necessary for greater congruence of the joint. Their main functions: uniform distribution of body weight on the joint and ensuring its stability during movement and in a static position.
This is extremely important, since if there were no menisci, then the whole body weight would concentrate on several points inside the joint, and this would lead to rapid trauma and disability.
Muscle
The extensor muscles are located on the front surface of the knee joint. They are attached to the tip of the femur on one side and to the patellar tendon on the other. When they contract, the leg extends in the joint, allowing a person to take a step forward. The main work is done by the quadriceps.
On the back of the thigh is a group of flexor muscles. Their attachment point is also on the femoral head, but the point of movement is on the posterior surface of the tibia, fixed by a strong tendon. Contraction of these muscles bends the knee.
Nerves
The most significant in the knee joint is the popliteal nerve. It is part of the large sciatic nerve and, leaving the joint, gives three branches. The first of them goes to the tibia and is located near its posterior surface. The second bends around the fibula and innervates the anterior and lateral surface of the lower leg. And the third goes down to the foot. This is a mixed nerve. They have both a motor and a sensitive component. With injuries in the knee joint, damage to both the common nerve and its branches is possible.
Blood supply
If we talk only about the joint, then it feeds the arterial circulatory network. It is formed by:
- medial and lateral anterior arteries of the knee;
- back arteries;
- mid knee artery;
- descending and bypassing knee arteries.
All of them are branches of the tibial artery, which originates from the external iliac artery. And she, in turn, leaves the common iliac.
Venous outflow is carried out along the veins of the same name that accompany each artery. The collector is the inferior vena cava, which returns blood back to the heart.
Causes of Knee Ligament Injuries
One of the most unpleasant injuries that can be received on the knee is damage to the cruciate ligament of the knee joint. Not only is the stability of the entire structure violated, the volume of voluntary and passive movements is reduced, so also the treatment process will be quite long.
The reasons for receiving such an injury can be both household injuries and shock, accidents, sharp turns. Most often it occurs in professional athletes - skiers, skaters, skaters, jumpers or wrestlers. In order to avoid this, it is necessary to observe safety measures, to prevent increased loads on the joint, it is also necessary to follow a diet that will maintain an adequate level of collagen, which preserves the elasticity of the ligaments.
Clinic
When a person with a similar injury is asked what he is complaining about, they hear in response something like this: "The knee hurts when bending and flexing." But he is silent about other symptoms.
- at the time of the injury, a click or crack was heard from the gap;
- there was instability in the knee, a feeling of "looseness";
- swelling in the knee during the first hours after the injury;
- accumulation of fluid in the joint cavity (symptom of fluctuation);
- restriction of movements due to pain or swelling.
Therefore, when the patient informs you that his knee hurts during flexion and extension, this may mean more than a rupture of the cruciate ligament. You need to conduct a full inspection before making any decision.
Damage classification
First degree:
rupture of the anterior cruciate ligament of the knee joint is slightly expressed, there is pain, slight swelling. Movement in the joint is somewhat limited, but mainly due to edema, and not due to trauma. Stability saved.
Second degree: there is a partial rupture of the cruciate ligament of the knee joint, supplemented by all the signs of injuries of the first degree. A distinctive feature is that such damage is prone to recurrence. And repeated trauma can be caused after much less effort than the first time.
Third degree: complete rupture of the anterior cruciate ligament of the knee joint. Severe pain, reactive edema with a significant restriction of passive and active movements. The joint is loose, its support function is violated.
Of course, this classification cannot accommodate all forms of knee ligament injuries, but it helps to structure them in severity.
Diagnostics
After the survey, collecting an anamnesis of life and health, the inspection phase begins. The doctor is trying to find out how subjective sensations coincide with real facts. First, he examines a healthy leg, including paying special attention to the knee. This is necessary in order to compare the damaged and the whole joint.
In order to check how much the cruciate ligament of the knee joint is damaged, the doctor tries to shift the shin up and anteriorly. If there is an injury, then he will succeed. There are several specific samples used in these cases.
After manual research comes the instrumental. Namely - radiography of the knee joint. It allows you to identify gross fractures and tears. The next step is magnetic resonance imaging. It allows you to establish a diagnosis with amazing accuracy. But sometimes it can even hurt. Since overdiagnosis becomes an occasion for completely unnecessary surgical interventions. The cruciate ligament of the knee joint can be damaged so that instability does not occur, and a huge gap is displayed on the monitor.
Conservative treatment
Traumatologists do not always incline their patients to surgery. In this case, the indication for the intervention is not the fact of the rupture itself, but the imbalance in the joint. This is a decisive factor. For joints and ligaments, immobilization and rest are often used until the moment of restoration of integrity. You can divide the treatment process into several stages.
- Acute period. The cruciate ligaments of the knee joint are injured. Treatment is aimed at reducing pain and joint swelling. The victim is better not to try to get to the hospital on their own. They apply cold to the site of the injury, give painkillers and provide complete rest to the affected limb. If there is an accumulation of blood in the joint, it is necessary to periodically suck it off with a syringe, preventing it from folding and settling on the articular surfaces, causing inflammation.
- A stale break. After the pain has subsided, you can begin training to strengthen muscles. For joints and ligaments, there is nothing better than a strong muscle frame that will keep them from overstretching and tearing. They start small, but each time the training becomes more intense, the range of motion increases. To limit movement, an orthosis is used (a bracket with an adjustable articulated system).
- Blank sheet. At this stage, the doctor examines the joint as if there was no injury. And if the results satisfy it, that is, mobility returned, there are no pain, instability and pathological signs, then the treatment can be considered successful.
But do not think that this is all over and you can immediately run the sprint distance. For a long time after the end of therapy, the patient will need to take care of the injured leg, perform special exercises, and train the thigh muscles.
Surgical treatment
Plastic surgery of the anterior cruciate ligament of the knee joint is performed if there is a lack of joint stability or it does not correspond to the norm. Usually it is carried out after conservative treatment, when there are positive changes relative to the muscular system.
As a rule, such operations are done six months after the injury. But if the gap was several years ago, and the symptoms appeared recently - this is not a reason to refuse surgical intervention. As a rule, athletes who have their anterior cruciate ligament of the knee torn are treated with this type of treatment. The operation is a prosthetic tendon. For him, they use both their own human ligaments and synthetic prostheses. Simple stitching of the ends of a torn bundle does not give positive results, and sometimes it is impossible purely technically, because of an inconvenient place. The new cruciate ligament of the knee joint must fully correspond to the old one, fulfill its functions and be correctly located.