The knee joint is the largest in the human body. And it is clear that the mechanics of his movements and anatomy will match. For medical students, there is nothing more difficult than artrosyndesmology, that is, the science of the 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 an articulation with the tibia just below. On 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 fits perfectly in shape to 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. He's tightshiny and very smooth. Its function is to soften the loads during the execution of movements and reduce friction between the bones. From above, this entire structure is covered with a connective tissue capsule.
Bundles
To hold three bones together, cartilage alone is not enough. A good fixation apparatus is required, which will be both elastic, resilient and durable. This function is performed by ligaments. They are formed from dense connective tissue and stretched between the bones.
Thus, on the lateral surfaces of the joint there are collateral ligaments that strengthen the capsule. There are two of them: lateral and medial. The function of these strands is to limit the mobility of the joint to the sides. 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 at the tibia. It prevents its forward movement and slipping out of the articular surface. The posterior cruciate ligament of the knee also originates at the tibia and inhibits its movement backwards in relation to the femur.
Together they help keep the joint in a state of balance, provide stability and smooth movement.
Menisci
Outwardly they look like ligaments, but in structure they are more similar to cartilage. Located midway between the tibia and femur and are necessary for greater congruencejoint. Their main functions are to evenly distribute body weight on the joint and ensure its stability during movement and in a static position.
This is extremely important, because if there were no menisci, then the entire weight of the body would be concentrated on several points inside the joint, and this would lead to rapid injury and disability.
Muscles
Extensors are located on the anterior surface of the knee joint. They are attached to the top of the femur on one side and to the tendon of the patella on the other. When they contract, the leg extends at the joint, allowing the person to take a step forward. The quadriceps muscle takes on the main work.
A group of flexor muscles is located along the back of the thigh. Their attachment point is also on the head of the femur, but the point of movement is on the posterior surface of the tibia, fixed by a strong tendon. Contraction of these muscles flexes the knee.
Nerves
The popliteal nerve is considered the most significant in the knee joint. It is part of the greater sciatic nerve and, leaving the joint, gives off 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. It has both a motor and a sensory component. Injuries in the knee joint can damage both the common nerve and its branches.
Blood supply
Ifto talk only about the joint, then it is fed by the arterial circulatory network. She is educated:
- medial and lateral anterior arteries of the knee;
- posterior arteries;
- median genicular artery;
- descending and bypassing genicular arteries.
They are all branches of the tibial artery, which originates from the external iliac artery. And she, in turn, comes out of the common iliac.
Venous outflow is carried out through 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 annoying injuries you can get on your knee is an injury to the cruciate ligament of the knee joint. Not only is the stability of the entire structure impaired, the volume of voluntary and passive movements is reduced, but also the treatment process will be quite long.
The causes of such an injury can be both household injuries and blows, accidents, sharp turns. Most often it occurs in professional athletes - skiers, skaters, figure skaters, jumpers or wrestlers. In order to avoid this, it is necessary to follow safety measures, not to allow increased stress on the joint, and you also need to follow a diet that will maintain a sufficient level of collagen, which maintains the elasticity of the ligaments.
Clinic
When a person with a similar injury is asked what he complains about, they hear in response something like this: "The knee hurts when flexing and extending." But he is silent about other symptoms.
- at the time of the injury, a click or crack was heard from the rupture;
- there was instability in the knee, a feeling of "looseness";
- swelling in the knee area during the first hours after the injury;
- accumulation of fluid in the joint cavity (fluctuation symptom);- restriction of movement due to pain or swelling.
So when a patient tells you that his knee hurts when he bends and straightens, it may mean more than just a cruciate ligament tear. You need to do a full inspection before making any decision.
Damage classification
First degree: rupture of the anterior cruciate ligament of the knee joint is slightly pronounced, there is pain, slight swelling. Movement in the joint is somewhat limited, but mainly due to swelling, and not due to injury. Stability preserved.
Second Degree: There is a partial tear in the cruciate ligament of the knee, complete with all the signs of a first degree injury. A distinctive feature is that such lesions are prone to recurrence. And re-injury can be caused with much less effort than the first time.
Third degree: Complete tear of the anterior cruciate ligament of the knee joint. Severe pain, reactiveedema with significant limitation of passive and active movements. The joint is loose, its support function is impaired.
Of course, this classification cannot accommodate all forms of knee ligament injuries, but it helps to structure them by severity.
Diagnosis
After the interview, the collection of an anamnesis of life and he alth, the examination phase begins. The doctor tries to find out how subjective sensations coincide with real facts. First, he examines a he althy leg, including paying increased attention to the knee. This is necessary in order to be able to compare the damaged and the whole joint.
In order to check how damaged the cruciate ligament of the knee joint, the doctor tries to move the lower leg up and forward. If there is an injury, then he will succeed. There are several specific tests that apply in these cases.
After manual research comes instrumental. Namely, an x-ray of the knee joint. It allows you to identify gross fractures and ruptures. 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 the monitor shows a huge tear.
Conservative treatment
Traumatologists do not always persuade their patients to undergo surgery. In this caseThe indications for intervention are not the fact of the rupture itself, but the imbalance in the joint. This is the deciding factor. For joints and ligaments, immobilization and rest are often used until integrity is restored. You can divide the treatment process into several stages.
- Acute period. Injured cruciate ligaments of the knee joint. Treatment is aimed at reducing pain and swelling of the joint. It is better for the victim not to try to get to the hospital on their own. Cold is applied to the injury site, painkillers are given and complete rest of the injured limb is provided. If there is an accumulation of blood in the joint, then it is necessary to periodically suck it out with a syringe, preventing it from coagulating and settling on the articular surfaces, causing inflammation.
- Stale break. After the pain has receded, you can start training to strengthen the muscles. For joints and ligaments, there is nothing better than a strong muscular 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. An orthosis (splint with adjustable joint system) is used to limit movement.
- Clean slate. At this stage, the doctor examines the joint as if there was no injury. And if the results satisfy him, that is, mobility has returned, there are no pain sensations, instability and pathological signs, then the treatment can be considered successful.
But don't think that it's all over and you can immediately run the sprint distance. Long after the endtherapy, the patient will need to take care of the injured leg, perform special exercises, train the thigh muscles.
Surgical treatment
Plasty of the anterior cruciate ligament of the knee joint is performed if there is no stability of the joint or it does not correspond to the norm. Usually it is carried out after conservative treatment, when there are positive changes in relation to the muscular apparatus.
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 a torn anterior cruciate ligament of the knee joint undergo this type of treatment. The operation is a prosthetic tendon. For him, both the person's own ligaments and synthetic prostheses are used. A simple stitching of the ends of a torn ligament does not give positive results, and sometimes it is not possible purely technically, due to an inconvenient place. The new cruciate ligament of the knee joint must fully match the old one, perform its functions and be correctly located.
