Habitual luxation of the patella. What is meant by patellar luxation? When the quadriceps muscle contracts, the patella dislocates.

The kneecap (patella) plays an important role in the human body. As long as it is healthy and performs its function normally, it is not even noticeable. But when the patella dislocates, the meaning and importance of this bone becomes clear. Life becomes significantly more difficult, movements are limited.

Natural knee protection

The kneecap is located in the front of the knee and is attached to it by ligaments and tendons. The main task of the patella is to protect the knee joint, its ligaments, and muscles from damage. This cup covers the knee like a shield.

A dislocation is a deformation (displacement) of the kneecap bone. This is accompanied by severe pain because the ligaments that attach the kneecap to the femur are damaged. The knee immediately loses the ability to move and remains bent. The injured person needs medical attention and hospitalization. At the hospital, his patella will be replaced. Sometimes he himself returns to his recess. In severe cases, the kneecap dislocates, and the ligaments are damaged, along with pieces of cartilage tissue torn off. Then the knee joint fills with blood.

Dislocation of the patella often occurs in athletes, dancers, teenagers, and people who prefer active recreation and tourism.

What are the reasons

The patella allows the knee muscles to flex the limb. Any damage to the cup negatively affects the normal movement of the legs and the range of flexion/extension.

Factors that provoke dislocation are:

• various types of knee injuries;
• operations performed on the joint;
• some diseases of the knee joint (for example, arthrosis);
• abnormal structure of the kneecap;
• anatomically high location of the patella;
• congenital defects in the structure of the legs (X-shaped shins).

A person may not be aware of some anomalies in the structure of the legs until the knee joint is damaged. For example, with a small patella (there is such a structural defect), the likelihood of damage to the patella increases.

The reasons may be:

• blows to the knee;
• falling to one's knee;
• a sharp turn around its axis.

Signs of kneecap damage

Manifestations of patellar dislocation are felt immediately. Moreover, this happens even to a person running or walking. He will feel a bend in his knee and a sharp pain. With extension, it is possible for the patella to return to its place.

Symptoms of dislocation:

• severe pain in the knee joint;
• inability to move the injured leg;
• swelling of the knee joint;
• distorted shape of the knee;
• when palpated, there is a displacement of the kneecap.

Important! It is impossible to set the kneecaps on your own, even if it seems that it has shifted not far. Any unprofessional actions lead to complications, which then have to be difficult and long to correct.

Classification of patellar injuries

Dislocations are congenital. This is a fairly rare pathology of the musculoskeletal system. The reason is poor development of the soft tissues entering the knee joint.

Acquired dislocations are of traumatic origin. They were obtained as a result of a fall on the knee, a blow to this place. If you get a dislocation up to two times a year or more, they talk about a habitual dislocation, an unstable patella.

Based on the direction of displacement, traumatologists distinguish several dislocations:

• lateral (the blow occurs from the side, more often when the leg is extended);
• vertical (impact from above or below, the patella enters the joint gap);
• rotational (the kneecap rotates around its axis).

Injury to the patella occurs less often if the leg is in a flexed position. The knee joint is pressed tightly against the femoral surface; such immobility protects it to some extent from injury.

Severity of patellar dislocation:

• first. Pain is not always present; damage is manifested by increased mobility of the kneecap;
• second. The displacement of the kneecap is clearly visible. In some cases it rotates around its own axis;
• third. The displacement of the patella has occurred quite far. The knee is difficult to straighten.

There is a chronically unstable patella. This is almost always a congenital developmental pathology. It is discovered when the child begins to walk; he often stumbles and falls. The kneecap in this case is very mobile, easily displaces and moves. In some cases, it is located on the side of the knee.

A slight displacement is treated with electrical stimulation, manual therapy, physical therapy, and massage. In difficult cases, surgery is performed. The prognosis is almost always favorable.

Important! When a small child begins to walk, you should pay attention to how he moves his legs. In any case of improper movement, it is better to consult a doctor.

First aid

Damage of this type often appears in places where there are no doctors and far from a medical facility. Dislocation of the knee occurs in skiers in the forest, during outdoor recreation. You must be able to provide the most basic assistance in order to protect the wound, alleviate the condition of the victim, and ensure his delivery to the doctors.

After a dislocation, it is necessary to ensure the immobility of the injured leg; there is no need to forcefully bend or straighten it, let it be in a comfortable position. If the knee is bent, it is better to place a folded blanket or jacket under it. It is better for the victim to be in a semi-sitting position. If he is in a lot of pain, you can give him a painkiller, remember which drug he was given, or leave the package to show the doctors.

To reduce the formation of swelling, a cold compress is applied to the injury site. If there are areas of open wound, you should try to stop the bleeding. Lubricate the edges of the wound with brilliant green, iodine, and bandage it with a bandage.

The victim must be taken to a medical facility. It is not recommended to step on the injured leg in order to avoid complications and the formation of a habitual dislocation. If possible, the victim should be carried on a stretcher or crutches should be built for him.

Preparing for treatment

If diagnostic examinations are necessary, an X-ray of the knee joint is performed, and in complex cases, a tomography is performed. When deciding on the methods of surgical intervention, arthroscopy of the knee joint is performed. This is a diagnostic method that allows you to very accurately determine the position of the kneecap and the condition of the joint.

Acute injuries are more amenable to reduction. Treatment of old dislocations: injuries that occurred more than three weeks ago, is more difficult. Treatment tactics depend on the severity of the injury. Traumatologists with orthopedists and surgeons determine, based on the data of a diagnostic examination and visual examination, which treatment methods to apply to the patient.

Attention! If a mechanical injury to the patella has occurred, but outwardly it does not seem to have shifted, it is better to consult a traumatologist. In addition to displacement, a fracture in this area is possible: a photograph can dispel doubts and help avoid complications in the future.

Carrying out therapy

Acute dislocation of the patella is reduced under local anesthesia using a conservative method. In order to ease the tension of the tendons, the leg is bent at the hip joint and straightened at the knee joint. The surgeon presses the patella in a special way, moving it into place. Next, plaster is applied.

To check the correctness of the reduction, an x-ray is taken. Also, such manipulation sometimes reveals osteochondral fragments that were not visible during diagnosis. The patient will be in a plaster splint for a month, sometimes more, depending on the nature of the damage. At this time, massage and physiotherapy will be carried out as prescribed by the physiotherapist. One month after the injury, weight bearing on the injured leg is allowed.

Surgery is suggested for old or habitual dislocations. The joint needs immobility for about a month to heal, this is ensured by casting. Next, a rehabilitation course is carried out, which includes therapeutic exercises, massage, swimming, and physiotherapy.

If the patella is dislocated, the treatment is supposed to be as modern as arthroscopy. Two punctures are made on the skin. Through one, a special device is inserted - an arthroscope, and through the other - the necessary instruments. The kneecap is realigned over a short period of time. Healing and recovery are faster with this method. The patient begins to move earlier, and the body tolerates such manipulation better.

After about two months, the patient is able to fully step on the injured leg, the knee joint makes the entire range of movements without pain.

Recovery period

Rehabilitation begins immediately after removing the fixing bandages. The duration of recovery can take from two to three months, it all depends on the condition of the knee joint, the severity of the injury, the general health and mood of the patient.

It is necessary to carry out a special set of therapeutic exercises, physiotherapy, massage. Some physiotherapy procedures, for example, UHF, are performed through a cast.

Complications and consequences

Timely access to a doctor, competently rendered first aid in case of injury, good treatment guarantee the exclusion of complications. But there is a risk of involuntary primary dislocation. This leads to the destruction of the joint ligaments and knee cartilage tissue.

Untimely treatment and an advanced stage contribute to the occurrence of various pathologies of the knee joint, for example, the development of arthritis. This is an inflammatory pathology that leads to damage to the joints and disruption of their motor function.

If the dislocation of the patella is incorrectly adjusted, then the negative consequences lead to sad results. There will be constant pain in the knee joint, it will appear more often (jumping, running), there is a high probability of habitual dislocation. There will be constant destruction of cartilage tissue, weakness of the ligamentous apparatus and muscles will appear. There may be a gradual restriction of movement of the knee joint of the injured leg.

Conclusion

A dislocated patella is a serious injury that can leave a person immobilized for a long time. For those who received such an injury while playing sports or dancing, a return to training is possible in the very near future.

You need to agree on the start time of classes with your doctor, but remember to gradually increase the duration and intensity of the load. Leg muscles need to be trained not only by athletes, but by all people, since movement brings not only health, but also joy into our lives.

Usually this bone is called the kneecap, but in medicine they use another term - the patella.

The patella is a small but very important bone. It is located in front of the knee joint. The patella is actually a sesamoid bone. In medicine, the so-called bones that are located inside the tendons. A person has several sesamoid bones, and the patella is the largest of them. The sesamoid bones, and the patella in particular, are needed to increase the efficiency of muscle traction and increase its strength, since these bones work like a block.

The patella (kneecap) is located in the thickness of the tendon that extends the tibia. This tendon is formed by the fusion of four muscles on the front of the thigh - the so-called quadriceps muscle. Below the patella begins the patellar ligament, which is attached to the front of the tibia (to the tibial tuberosity). The patellar ligament is sometimes referred to as the patellar ligament proper. When the leg is extended, the patella “floats” above the knee joint, located in front and above the joint space, but when the knee is bent, the patella fits into a special notch (groove) between the two condyles of the femur and begins to work like a block. This place in the knee joint is also called the patellofemoral joint (or patellofemoral joint, from the Latin terms patella - patella and femur - thigh).

The inside of the patella is covered with a thick layer of cartilage, which is needed to slide along the cartilage of the femoral condyles. The patella cartilage is the thickest cartilage in humans - its thickness can exceed 5 millimeters! Naturally, it is thick for a reason, but because the patella experiences very strong loads. You can learn more about the anatomy of the knee joint and the patella in particular on our website.

Left - knee in flexion position. The patella fits into a groove on the femur, causing it to act as a pulley, increasing the traction efficiency of the quadriceps tendon.

In order for the patella to work as a block during extension in the knee joint to be as effective as possible, it must fit into the groove between the condyles of the femur correctly, i.e. centered. If the patella lies in the groove incorrectly, not in the center, then they talk about the inclination of the patella.

On the left, the patella is centered. The width of the inner and outer parts of the femoral-patellar joint is the same. Right - the patella is displaced outwards. The inside of the joint is much wider than the outside.

Almost always, when there are problems in the patellofemoral joint, the patella moves outward, and only in very rare cases does the patella move inward. If the tilt is slight, then we speak of lateral hyperprepression (i.e., increased pressure of the patella on the lateral condyle of the femur), or medial hyperpression if the patella is displaced medially. With greater displacement of the patella, subluxation appears, and finally, if the patella completely extends beyond the groove between the condyles of the femur, then they speak of a dislocated patella.

From left to right: normal joint (the width of the inner and outer parts of the joint is the same), patellar tilt or lateral hyperpression (the outer gap is narrower than the inner), subluxation of the patella (part of the patella has moved out beyond the condyle) and dislocation (the patella has completely moved outside the joint)

Tilt and subluxation of the patella are one of the variants of its instability, i.e. conditions where the patella may subluxate or completely dislocate.

Causes

Tilt and subluxation can be caused by various factors, most often several at the same time. Among the main reasons are the following:

• Excessive tension in the external patellar suspensory ligament or weakness in the internal patellar suspensory ligament (may develop due to a rupture of this ligament);
• weakness of the vastus medialis (internal) muscle;
• abnormal leg shape:
  • X-shaped or valgus curvature of the legs (deviation of the legs outward);
  • dysplasia of the femoral condyles;
  • hyperextension in the knee joint;
  • high position of the patella - patella alta;
  • the outer position of the tibial tuberosity - the place to which the patellar ligament is attached
  • internal rotation of the lower leg (can be due to a congenital feature - when a person rakes his feet inward when walking or can develop as a result of flat feet).
  • other rare causes (femoral anteversion, patellar dysplasia, etc.)

The patella has two ligaments that hold it on the sides (sometimes they are not called ligaments, but retinaculum). The external ligament pulls the patella outward and does not allow it to dislocate inward, and the internal ligament, on the contrary, pulls the patella inward and does not allow it to dislocate outward.Excessive tension in the external patellar suspensory ligament or weakness in the internal patellar suspensory ligament (which can develop as a result of a rupture of this ligament) can cause the patella to lie in the groove between the femoral condyles not centered, but with a large displacement outward.

Normally, the patellar ligament (external and internal) is balanced and the patella is centered. If this balance is disturbed, for example, when the internal ligament is torn, the patella will tend to move outward due to uncompensated traction of the external ligament.

The stability of the patella is ensured not only by ligaments, but also by muscles. In particular, the vastus medialis (internal) muscle pulls the patella inward. This muscle is part of the quadriceps femoris muscle, which consists of four heads. If the vastus internus muscle is weak, it will not fully stabilize the patella and it will move outward.

Thigh muscles, front view. The quadriceps femoris consists of four muscles (heads): 1 - Rectus femoris, 2 - Vastus lateralis, 3 - Vastus medialis, 4 - Vastus intermedius. The vastus medialis (internal) muscle keeps the patella from moving outward (its pull is marked with black translucent arrows)

X-shaped or valgus curvature of the legs (deviation of the legs outward). If you look at the skeleton from the front, you can see how the femur connects to the shin at an angle called the quadriceps angle or Q-angle. The size of the angle Q is determined by the width of the pelvis. Women have a wider pelvis than men, so the Q-angle is larger in women than in men. In addition, congenital X-shaped deformity of the legs can lead to an increase in the Q-angle. A large Q angle causes the patella to move outward more easily. In addition, with a large Q-angle, the anterior cruciate ligament ruptures more easily.

Q-angle. The normal value is 20° for women and 15° for men. An abnormal Q-angle does not necessarily cause anterior knee pain or patellar subluxation, but it does contribute to patellar subluxation when the quadriceps muscle contracts.

Dysplasia of the femoral condyles. The groove between the femoral condyles must be deep enough to support the patella. With dysplasia of the condyles of the femur, i.e. a congenital feature of bone development, the groove is less deep and the patella moves outward more easily. Scientific studies have shown that in people with femoral condyle dysplasia, the groove depth is on average 7 millimeters less. There are several variants of dysplasia: dysplasia of both condyles, isolated dysplasia of the external or internal condyles, in addition, dysplasia can be of varying intensity. Dysplasia can be determined by axial radiographs or magnetic resonance imaging (MRI), and the accuracy of these two methods in determining dysplasia is approximately the same, but MRI, unlike radiographs, allows you to evaluate not only bones, but also soft tissues (cartilage, ligaments, etc.) d.).

Magnetic resonance imaging (MRI) of the knee joint. These images show a section of the knee joint at the level where the patella fits into the groove between the femoral condyles. On the left is a normal groove, on the right is a groove with condylar dysplasia. Please note that with dysplasia, the groove is less deep and the patella will move outward more easily. M - internal (medial) condyle, L - external (lateral) condyle

Hyperextension in the knee joint andthe high position of the patella (patella alta) leads to the fact that the patella will also slip out of the groove between the condyles and shift outward. When hyperextended, the patella is pushed out of the groove, and with a congenital high position of the patella, it lies in the groove higher, where the groove is smoothed out and is not so deep as to support the patella.

The outer position of the tibial tuberosity is the place to which the patellar ligament is attached. In some people, the tibial tuberosity is located laterally (i.e., displaced outward), in which case the patella will also tend to move outward.

A similar problem occurs with internal rotation of the tibia - i.e. when the shin is twisted inward too much. This situation can occur due to a congenital feature - when a person rakes his feet inward when walking, or can develop as a result of flat feet.

Inward rotation (torsion) of the tibia promotes outward displacement of the patella

Symptoms of patellar tilt/subluxation

A typical manifestation of incorrect sliding of the patella in the intercodylar groove is pain in the anterior part of the knee joint and a feeling of instability. Sometimes patients with a tilted patella can say for sure that the pain is exactly located under the patella (patella), but in many cases the pain is diffuse and affects the entire front surface of the knee. And finally, in the third case, the pain affects the entire knee joint.

A feeling of instability is an optional but common sign of patella tilt/subluxation.

Often, in addition to pain during flexion and extension of the knee joint, a painful click or crunch can occur under the patella. These painful clicks and crunches in the knee joint under the patella are due to improper sliding of the patella in the intercondylar groove.

When the leg is flexed, the patella usually slides along the intercondylar groove of the femur, but when almost fully extended, it shifts outward. At this point, patients usually feel a “failure” in the joint, although true dislocation of the patella rarely occurs in them.

Tilt/subluxation of the patella is often preceded by trauma that damages structures that prevent the patella from moving outward. For example, often chronic subluxation of the patella develops after a dislocation of the patella. In addition, patella tilt/subluxation can develop as a complication after some knee surgeries.

Since, when the patella is tilted/subluxed, it slides incorrectly in the intercondylar groove, with great outward pressure (more often, in rare cases, there is increased pressure from the inside - internal hyperpressure), then with a long-term tilt/subluxation, the cartilage covering the patella begins to suffer from this uneven pressure and condyles, and develops patelofemoral arthrosis, which is part of knee arthrosis.

With long-term tilting/subluxation of the patella, fluid may accumulate in the joint (synovitis), which will be manifested by swelling of the knee joint mainly above the patella.

In addition, when the patella dislocates, an injury to the patellar cartilage (osteochondral fracture) may occur, which will also contribute to the development of arthrosis of the knee joint.

Medical examination

As we have already noted, the most common complaint with tilting and subluxation of the patella is pain. During the examination, the doctor will first ask you about what movements this pain occurs with and where it is located. As a rule, pain appears when the knee joint is bent more than 30 degrees - because before this the patella does not come into contact with the intercondylar groove. The pain usually worsens when the quadriceps muscle is tense, such as when going up or down stairs.

During the examination, the doctor pays attention touniform development of the extensor muscles of the knee joint. With tilt and subluxation of the patella, atrophy and weakness of the vastus medialis muscle of the thigh can often be seen.

In addition, the doctor during the examination pays attention to all other factors that contribute to the development of the tilt / subluxation of the patella: posture and gait, high standing of the patella, abnormally large Q-angle, X-shaped curvature of the legs,anteversion of the femur, patellar or femoral dysplasia, flat feet, and joint hypermobility.

An approximate assessment of the trajectory of the patella movement can be carried out by slowly unbending the sitting patient's leg at the knee joint. Normally, the patella should move in a straight line. In some cases, the J-sign can be seen, a trajectory resembling an inverted J as the patella moves outward as the joint is extended. With internal subluxation of the patella, you can see the reverse J-sign due to the displacement of the patella in the position of full extension inwards. If the J-sign is noticeable when extending freely hanging legs, then this may indicate weakness of the vastus medialis muscle of the thigh, which determines the tactics of treatment.

The trajectory of the patella during knee extension from point A to point B. When the patella is tilted / subluxated, it does not go in a straight line, and bends outward as the knee is extended, which looks like an inverted letter J, therefore this symptom is called J-sign

To determine the inclination and subluxation of the patella, the doctor conducts special tests: when pressing on the patella, when you try to move the patella outward with your fingers, pain and / or fear may appear, a premonition of a dislocation of the patella. In addition, the increased mobility of the patella, detected by this test, will also be in favor of lateral tilt/subluxation of the patella.

The lateral suspensory ligaments of the patella are also carefully examined. The pain of these ligaments upon palpation often accompanies their overload in patients with patellar subluxation. Tenderness in the area of ​​the medial epicondyle - the so-called Bassett's sign - is characteristic of an injury to the medial femoral-patellar ligament.

The test to detect excess traction on the lateral suspensory ligament is to measure the inclination of the patella. The test is carried out with the knee joint relaxed and passively extended. When it is noticed that the outer edge of the patella has risen, the inner edge is fixed. Normally, the angle between the horizontal plane and the outer edge of the patella should be about 15°. At lower values, the cause of pain in the anterior knee joint may be excessive tension in the lateral suspensory ligament; according to indications, mobilization of the outer edge is carried out. When the patella is displaced outward, the patient sometimes tries to reduce the range of motion to avoid pain. This symptom most likely indicates hypermobility or instability of the patella.

The displacement of the patella along the articular surface from side to side makes it possible to judge the integrity of the structures that limit its mobility. Outward displacement is prevented by the external part of the joint capsule, the external suspensory ligament and the oblique part of the vastus medialis muscle. The patella is moved outward by hand and the resulting displacement relative to the neutral position is measured in quarters of the width of the patella. A shift of more than three quarters indicates hypermobility; less than one quarter with medial displacement indicates excessive tension of the medial suspensory ligament. The described test can provide valuable information about the condition of the ligamentous apparatus, but it is relatively subjective.

Palpation of the patella: the doctor presses on the patella and tries to move it to the sides, assessing the range of mobility and intensity of pain. The picture shows the Basset test

Fear, premonition of patellar dislocation. When the patella is displaced outward by the doctor's fingers, the patient may feel fear of dislocation and increased pain. Notice how the patient tries to stop the doctor. Illustration Hughston JC, Walsh WM, Puddu G: Patellar subluxation and dislocation. In: Saunders monographs in clinical orthopedics, vol 5, Philadelphia, 1984, Saunders with modifications by travmaorto.ru

In most tests, the patient lies on his back, but you can also examine the knee joint in the position of the patient on the stomach. In this case, the immobility of the pelvis and the inability to flex the hip make it possible to more accurately assess the flexibility of the articular structures during extension. In addition, anterior anteversion of the femur and rotation of the tibia can be easily identified. Decreased internal rotation amplitude can be an early sign of hip osteoarthritis, which sometimes causes knee pain.

To clarify the diagnosis, additional research methods are carried out, the most important of which are radiography, computed tomography (CT) and magnetic resonance imaging (MRI). The initial examination of the femoropatellar joint includes AP and lateral X-rays in the standing position. An AP radiograph may show significant subluxation, fracture, or deformity of the patella. Before judging the presence of a subluxation, you need to make sure that this is not a laying error. Lateral radiographs can also provide valuable information. First of all, it allows you to get an idea of ​​the depth and relief of the intercondylar sulcus. Its center corresponds to the most posterior line, and the articular surfaces of the lateral and medial condyles can be distinguished separately. Using these points, the depth of the furrow is measured and dysplasia is detected. On the lateral radiograph, you can determine the high or low standing of the patella, calculate the ratio of the length of the patellar ligament to the diagonal of the patella. Normally, this ratio is 0.8-1.0; Larger values ​​indicate a high standing of the patella, smaller values ​​indicate a low one.

Additional information about the position of the patella is provided by radiography in the axial projection when the knee joints are flexed at an angle of 20° (according to Laurin) and at an angle of 45° (according to Merchant). To reduce radiation exposure, it is usually sufficient to take an image in one of these projections. Axial radiographs are very useful for identifying patellar tilt and subluxation. These radiographs determine two angles: the external femoral-patellar angle and the congruence angle. The first is formed by lines drawn through the femoral condyles and along the lateral facet of the patella. Typically these lines radiate outward; if they are parallel or diverge inward, then this most likely indicates a tilt of the patella. The congruence angle is used to identify patellar subluxation. To construct the congruence angle, first draw a bisector of the angle formed by the slopes of the femoral condyles, and then measure the angle between this bisector and a line drawn from the lowest point of the slope to the middle part of the edge of the patella. Normal congruence in the knee joint bent at an angle of 45° is 6 ± 11°. At this angle of flexion, the patella should be located in the center of the articular surface, and a change in the degree of congruence indicates its possible subluxation.

Positioning the patient for taking radiographs according to Merchant (A.C. Merchant)

X-ray in the axial projection according to Merchant - the tilt of the patella is visible, uneven width of the joint space - it is smaller on the outside than on the inside

Computed tomography (CT) allows one to determine tilt and subluxation somewhat more accurately than radiographs in the axial projection, which is due to the absence of projection distortions and the overlapping of shadows of anatomical structures on each other. In addition, CT scans can be obtained at any knee flexion level. This is especially important for identifying tilt and subluxation of the patella with the knee practically extended, when the patella is deprived of fixation from the side of the lateral femoral condyle.

As we have already noted, an important factor in the development of patellar tilt/subluxation is the position of the tibial tuberosity, to which the patellar ligament is attached. An accurate assessment of the spatial relationship of the tuberosity, patella, and intercondylar groove can again be made on computed tomography (CT) scans.The most important indicator on them will be the TT-TG index (from the English terms tibial tuberosity and trochlear groove).To do this, measure the distance between the tuberosity and the intercondylar groove of the femur by superimposing two sections in the axial projection one on top of the other. A distance greater than 15 mm indicates patellar subluxation with a specificity of 95% and sensitivity of 85%.

Computer tomogram. In this figure, two sections are superimposed on each other: at the level of the intercondylar groove and at the level of the tibial tuberosity. Thanks to this overlay, the distance between the tuberosity and the sulcus can be measured. Normally, it varies from 10 to 15 mm. In this image it is 21 mm, indicating patellar subluxation.

Magnetic resonance imaging (MRI) can be used to confirm findings from CT scans and radiographs, but is more suitable for diagnosing soft tissue conditions and assessing cartilage damage. The method has proven itself to detect injuries associated with patellar dislocation: avulsion of the medial femoropatellar ligament from the femur or, less commonly, from the medial facet of the patella; joint effusion; areas of increased signal intensity and damage to the vastus medialis oblique muscle; hematomas in the area of ​​the lateral femoral condyle and the medial facet of the patella.

Since pain in the knee joint can often be due to other reasons not related to the position of the patella, MRI is used quite often.

Treatment

Conservative treatment. Treatment of patellar tilt/subluxation is mainly conservative, i.e. non-surgical. The basis of treatment is physical exercise. Quadriceps strength and endurance are best trained with static, low-range extension exercises with the knee flexed between 0 and 30 degrees (i.e., with minimal contact between the patella and femur). The exercises are aimed at restoring the balance of the extensor muscles, special attention should be paid to the oblique part of the vastus medialis muscle.

Exercises for patellar flexion/subluxation

For additional stabilization of the patella, special orthopedic bandages, orthoses, and bandages can be used, but it is necessary that the patient understands the need to wear them. Orthoses also improve the architecture of the lower extremity, especially in patients with a tendency to have an X-shaped curvature of the legs, which aggravates patellar instability.

Taping is very effective, which allows you to compensate for the outward displacement of the patella and relieve pain in the knee joint against the background of hyperpresia of the outer parts of the femoral-patellar joint.

Thoughtful conservative treatment is effective in most cases, but in some cases it is not successful and then surgical intervention is often necessary.

Surgery. As with other diseases of the patellofemoral joint, accompanied by pain in the anterior part of the knee joint, arthroscopy is first performed: a video camera is inserted into the joint through a one-centimeter long puncture and the knee is examined from the inside. During arthroscopy, not only the femoral-patellar joint, the condition of the patellar cartilage, the correct insertion of the patella into the intercondylar groove are assessed, but also all other structures of the knee joint are assessed: cruciate ligaments, menisci, cartilage, etc.

If there is no subluxation of the patella, but only a tilt of the patella with lateral hyperpression, then arthroscopic mobilization of the outer edge of the patella is performed. To do this, the entire external suspensory ligament and the oblique part of the vastus externus muscle are dissected.

Scheme of the operation of arthroscopic mobilization of the outer edge of the patella (lateral release)

We have described the simplest and most common operation used to treat patellar tilting and subluxation. But, as we have already noted, there are many different reasons for the development of tilt and subluxation of the patella. And for some reasons, one operation is performed, and for another, another. In this article, we will not describe the algorithm for choosing the appropriate operation depending on certain reasons that led to the incorrect position of the patella in the intercondylar groove, since in fact this algorithm is relevant for a more severe option - chronic instability of the patella, manifested by complete dislocations of the patella. Usually, when the patella is tilted/subluxated, arthroscopic mobilization of the outer edge of the patella is sufficient, but in some “advanced” cases, operations are used from the arsenal of methods for treating chronic patellar instability, which are described in detail in a separate article on our website.

Forecast

The prognosis in most cases of patellar tilting or subluxation is favorable. With both the correct conservative and surgical treatment tactics, a full recovery and even a return to sports activities is possible after restoration of mobility, stability and strength. The intensity of exercise and training should be increased gradually. The rehabilitation course is selected in accordance with the operation performed. Rest is required while soft tissue and bone heal.

Smetanin Sergei Mikhailovich

traumatologist - orthopedist, doctor of medical sciences

Moscow, st. Bolshaya Pirogovskaya, 6., bldg. 1, metro station Sportivnaya. Registration strictly by phone!!!

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Education and professional activities

Education:

In 2007 he graduated with honors from the Northern State Medical University in Arkhangelsk.

From 2007 to 2009, he completed clinical residency and correspondence postgraduate studies at the Department of Traumatology, Orthopedics and Military Surgery of the Yaroslavl State Medical Academy on the basis of the Emergency Hospital named after. N.V. Solovyova.

In 2010 he defended his dissertation for the degree of candidate of medical sciences on the topic "Therapeutic immobilization of open fractures of the femur" . Scientific supervisor - Doctor of Medical Sciences, Professor V.V. Klyuchevsky.

Professional activity:

From 2010 to 2011 he worked as a traumatologist-orthopedist at the Federal State Institution "2nd Central Military Clinical Hospital named after P.V. Mandryk".

Since 2011, he has been working in the clinic of traumatology, orthopedics and joint pathology of the First Moscow State Medical University. THEM. Sechenov (Sechenov University), being an associate professor of the Department of Traumatology, Orthopedics and Disaster Surgery.

Conducts active scientific work.

Internships:

April 15-16, 2008 JSC course "AO Symposium Pelvic Fractures" .

April 28-29, 2011 - 6th educational course "Problems in the treatment of common fractures of the bones of the lower extremities" , Moscow, State University of Monika named after. M.F. Vladimirsky.

October 6, 2012 - Atromost 2012 "Modern technologies in arthroscopy, sports traumatology and orthopedics" .

2012 - training course on knee replacement, prof. Dr. Henrik Schroeder-Boersch (Germany), Kuropatkin G.V. (Samara), Yekaterinburg.

February 24-25, 2013 - training course “Principles of total hip replacement”

February 26-27, 2013 - training course "Basics of total hip replacement" , FSBI "RNIITO im. R.R. Harmful" of the Ministry of Health of Russia, St. Petersburg.

February 18, 2014 - workshop on orthopedic surgery "Endoprosthetics of the knee and hip joints" ,Dr. Patrick Mouret, Klinikum Frankfurt Hoechst, Germany.

November 28-29, 2014 - training course on knee replacement. Professor Kornilov N.N. (RNIITO named after R.R. Vreden, St. Petersburg), Kuropatkin G.V., Sedova O.N. (Samara), Kaminsky A.V. (Kurgan). Subject "Course on ligament balance in primary knee replacement" , Morphological Center, Yekaterinburg.

November 28, 2015 - Artromost 2015 "Modern technologies in arthroscopy. sports traumatology, orthopedics and rehabilitation" .

May 23-24, 2016 - congress "Medicine of emergency situations. Modern technologies in traumatology and orthopedics, education and training of doctors" .

May 19, 2017 - II Congress “Emergency Medicine. Modern technologies in traumatology and orthopedics.”

May 24-25, 2018 - III Congress “Emergency Medicine. Modern technologies in traumatology and orthopedics.”

Annual scientific and practical conference with international participation "Vreden Readings - 2017" (September 21 - 23, 2017).

Annual scientific and practical conference with international participation "Vredenov Readings - 2018" (September 27-29, 2018).

November 2-3, 2018 in Moscow ("Crocus Expo", 3rd pavilion, 4th floor, 20th hall) conference"TRAUMA 2018: A multidisciplinary approach."

Associate member of the InternationalInternational Society of Orthopedic Surgery and Traumatology (SICOT - French Société Internationale de Chirurgie Orthopédique et de Traumatologie; English - International Society of Orthopedic Surgery and Traumatology). The society was founded in 1929.

In 2015, he was awarded the gratitude of the rector for personal contribution to the development of the university .

From 2015 to 2018 He was an applicant for the Department of Traumatology, Orthopedics and Disaster Surgery of the Medical Faculty of Sechenov University, where he studied the problem of knee joint arthroplasty. The topic of the dissertation for the degree of Doctor of Medical Sciences: "Biomechanical substantiation of knee arthroplasty for structural and functional disorders" (scientific consultant, doctor of medical sciences, professor Kavalersky G.M.)

Protection dissertation work took place September 17, 2018 V dissertation council D.208.040.11 (Federal State Autonomous Educational Institution of Higher Education First Moscow State Medical University named after I.M. Sechenov of the Ministry of Health of Russia (Sechenov University), 119991, Moscow, Trubetskaya St., 8, building 2). Official opponents: doctor of medical sciences, professors Korolev A.V.,Brizhan L.K., Lazishvili G.D.

He is a doctor of the highest qualification category.

Scientific and practical interests: endoprosthetics of large joints, arthroscopy of large joints, conservative and surgical treatment of musculoskeletal injuries.

Anatomy of the patella

The patella is the largest sesamoid bone.

The sesamoid bone is usually located in the thickness of the tendons and serves to increase the traction of the muscle. Attached to the inferior pole of the patella is the patellar ligament, which runs to the tibial tuberosity. The quadriceps femoris muscle is attached to the superior pole of the patella. The patella is involved in the extension of the lower leg. Patella retinaculums are attached to the inner and outer surfaces of the patella, which help keep the patella centered during movement. When extended, the patella is free in the cavity of the knee joint, and when flexed, it fits tightly to a special groove on the femur - the femoral patella joint is formed. The surface of the patella, which slides along the femur, is an articular surface, covered with thick cartilage.

Two surfaces of the patella - on the right is the articular surface

Patellar instability. Patellar instability is a condition in which the patella tends to move from a central position to the side.

Above - lateral radiograph, below - axial, which shows the normal relationship of the patella and femur

There is hyperpression of the patella, that is, increased pressure on the articular facet - lateral hyperpression, that is, increased pressure on the external condyle of the femur, medial hyperpression, that is, increased pressure on the internal condyle of the femur. With lateral hyperpression, the patella presses on the outer facet; with even greater displacement, subluxation of the patella appears; with complete displacement, dislocation occurs.

On the left - subluxation of the patella, a tendency to move outwards; right - dislocation of the patella

Causes of dislocation of the patella

Weakness of the internal retinaculum ligament, weakness of the thigh muscle, dysplasia of the femoral condyles, high position of the patella, weakness or overstrain of the patellar retinaculum and others.
The anatomical features of the femoral condyles play a key role in the stability of the patella. There is dysplasia of the lateral condyle, and the patella moves outward more easily; dysplasia of the internal condyle, in which it is easier for the patella to move medially.

Condylar dysplasia is clearly visible on axial x-rays or MRI studies.

Symptoms of a luxated patella

Symptoms of patellar luxation are pain in the anterior part of the knee joint, a feeling of instability of the kneecap, a painful click when moving the knee joint - this occurs when the new positioning of the patella is incorrect.

Schematic displacement of the patella outwards

One of the causes of patellar luxation is damage to the internal retinaculum of the patella.

Synovitis is excessive accumulation of fluid in the knee joint. During the examination, the doctor interviews the patient to examine the leg. To determine the inclination of the patella, the doctor performs special tests - when pressing outward on the patella, the pain may increase; increased pain when pressing on the patellar retinaculum.

Examination of a leg with suspected patellar instability

Patellar dislocation outwards

Diagnosis of patellar dislocation

To clarify the diagnosis X-rays, magnetic resonance imaging or computed tomography are performed. X-rays are taken in direct, lateral, axial projections - at an angle of 20 degrees or 45 degrees of flexion. Computed tomography allows you to more accurately determine the displacement of the patella. In addition, computed tomography can determine the position of the tibial tuberosity. The most important indicator will be the TT - TG index. This is the distance between the tibial tuberosity and the groove of the femur in the axial projection - a distance of more than 15 mm indicates in most cases a subluxation of the patella.

Treatment of kneecap dislocations

Treatment of patellar dislocation can be conservative or surgical. The basis of conservative treatment includes physical exercises, taping and the use of special orthoses.

Surgery for dislocated patella

As a rule, with pain in the anterior part of the knee joint, arthroscopy of the knee joint is performed, which assesses the position of the patella, the condition of the cartilage of the bones, the integrity of the menisci, ligaments. If there is only lateral hyperpression, then arthroscopic mobilization of the external sections is performed - the external supporting ligament is dissected.

If the patellar retinaculum is damaged, an operation is performed to strengthen it. One of the options for plastic retinaculum is surgery Medial Patellofemoral Ligament ( MPFL ). The essence of the operation is to replace the torn patellar retinaculum using a graft from the patient's tendon and fix it to the patella and femur at the point when, when bending the knee joint, the grafts are evenly tensioned.

Schematically shows the fixation of the graft to the patella and femur using anchor fixators (MPFL)

Anchor clamp

Reconstruction scheme (MPFL)

Knee brace

In the postoperative period, the leg is fixed in an orthosis, and the patient gradually develops movements and rehabilitation. Return to sports is possible after 6 months.

Dislocation is usually understood as deformation of the shape of articular joints. This injury is characterized by sharp, increased pain.

Patellar luxation is the most common knee injury that occurs in children and adults.

Among women, this pathology is observed more often, as it is associated with the anatomical features of the structure of the articulation of the femur and patella.

Symptoms

With acute traumatic displacement of the knee, the patient complains of severe and sharp pain and swelling in the area of ​​the kneecap. The victim cannot move the joint, since any attempts to move the leg cause intense pain.

When a dislocation occurs, the knee moves to the side and increases in volume. Changes in the structure of the knee joint can be felt and determined in which direction the displacement occurred. This can be done by an experienced specialist during a visual inspection.

In some cases, the patella may fall into place on its own, i.e. spontaneous reduction occurs. The victim still feels discomfort in the joint.

Anatomy and mechanism of dislocation

In front of the knee joint there is a rounded bone - the patella. This bone is the largest and is located in the thickness of the tendon.

The inside of the kneecap is covered with cartilage and supported by ligaments and tendons. They perform a protective function, protect muscles and ligaments from various damage, and prevent lateral displacement.

The quadriceps tendon attaches to the superior surface of the kneecap with a rounded edge.

At the bottom is the patellar ligament, which attaches to the tibia. The posterior surface of the patella consists of 2 parts: internal and external.

Each is attached to the surface of the sesamoid bone and results in a knee joint.

When bending the leg, the kneecap should be in the central part in the middle of the femoral condyle. This position characterizes the normal state of the patella.

In the event of a fall and impact, the quadriceps muscle contracts. Dislocation of the lateral part of the patella occurs when the lower leg is extended. In a bent position, dislocation is practically impossible, since the patella is tightly adjacent to the intercondylar joints.

Predisposing factors

Most cases of patellar dislocation occur among athletes, but it also occurs among people leading an active lifestyle. Various reasons can provoke the appearance of a dislocation, the most common are:

• Various knee injuries;
• Arthrosis of the knee joint;
• High location of the patella;
• Previous operations on the kneecap;
• Condylar dysplasia;
• Abnormal structure of the patella;
• Defects in the shape of the legs.

A person may not know about congenital physiological abnormalities until the patella is damaged. The risk of injury increases with a shallow patellar cavity.

Types of dislocation

In traumatological practice, depending on the origin of the injury, congenital and traumatic types are distinguished.

Congenital dislocation of the patella It is quite rare among diseases of the musculoskeletal system. The main cause of physiological pathology is the underdevelopment of the soft tissues that form the joint.

Acquired or traumatic dislocation appears as a result of indirect trauma. This could be a fall, a strong blow to the knee, or other reasons.

Traumatic damage to the patella can recur 1-2 times a year. In this case, they talk about habitual dislocation of the patella.

Depending on how long ago the damage occurred, there are spicy And outdated dislocation.

Taking into account the direction of displacement, there are: lateral, vertical, and rotational dislocations.

Lateral dislocation appears after a fall on an extended shin or when there is a blow to the lateral surface of the patella.

Vertical dislocation occurs rarely and is characterized by horizontal displacement of the patella with entry into the joint gap.

Rotational dislocation in contrast to the vertical view, the patella rotates around its axis vertically.

Diagnostics

If you consult a doctor in a timely manner, the acute form of dislocation can be easily treated and does not develop into an old form.

If a calyx defect is detected, it is important to determine the reasons that caused this pathology.

Initially, the orthopedist will examine the damaged area, and then prescribe an examination.

Among modern diagnostic methods for confirming a dislocation of the patella, they use: X-ray, computed and magnetic resonance imaging.

X-ray examination is carried out in two projections. Typically two radiographs of each knee are compared. The study is carried out in a standing position in two projections. If necessary, radiography of the axial projection is performed at different angles.

A more informative and accurate method is computed tomography. This method can determine the tilt angle, but not the projection distortion.

To confirm the diagnosis and prescribe the correct treatment, magnetic resonance imaging is used.

It can be used to determine the exact location and extent of damage to the entire area around the kneecap.

This method is not prescribed in the presence of metal structures, a large number of tattoos, etc.

The final diagnosis is made by a traumatologist or orthopedist, taking into account the examination, clinical course and research results.

Treatment and surgery

In the treatment of acute patella dislocation, a conservative method is used, which includes several stages.

To reduce pain and swelling of the skin, cold is applied to the damaged area. Cold compresses are used for this.

After that, the traumatologist gently sets the injured patella in a closed way (finger pressure on the cup) to avoid damage to the cartilage.

Then a plaster splint is applied from the ankle to the gluteal fold for 1.5 months. During this period, physiotherapeutic procedures and massage of the quadriceps are prescribed. The rehabilitation period includes performing therapeutic exercises.

After removing the plaster cast, a control X-ray examination is performed to determine the accuracy of reduction and to identify the osteochondral bodies formed during injury.

If the dislocation has passed into an old stage and has a prescription of more than three weeks, then they resort to surgical treatment. Given the extent of the injury, the doctor selects a way to eliminate damage to the patella.

The following surgical treatment methods exist:

• Arthroscopic suture of the knee joint according to Yamomoto;
• Heineke-Wreden operation;
• Campbell's operation;
• Arthroscopic plastic surgery.

Surgical treatment is based on a thorough examination of the damaged area, sanitation, and suturing of the fibrous capsule.

After the operation, a plaster bandage is applied to the patient to immobilize the knee joint. After 2-3 months, mobility returns.

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Source: http://www.knigamedika.ru/travmy-i-otravleniya/koleno/vyvix-nadkolennika.html

Patella dislocation

Patella dislocations constitute 0.4-0.7% of the total number of dislocations.

The likelihood of patellar dislocation increases with a shallow patellar cavity, a poorly developed lateral femoral condyle, and a violation of the relationship between the axis of the quadriceps muscle and the patellar ligaments.

Usually, until the moment of injury, these anatomical features do not appear in any way and go unnoticed. There are lateral, vertical and torsion dislocations of the patella.

Regardless of the type of dislocation, it is accompanied by severe pain, soreness and limitation of movements in the knee joint, palpably determined by the displacement of the patella. Treatment consists of realigning the patella and fixing it with a plaster cast.

Patella dislocations constitute 0.4-0.7% of the total number of dislocations. The patella is a small, rounded, flat bone located on the front surface of the knee joint.

The tendons of all four heads of the quadriceps femoris muscle are attached to the patella on top.

The tendon fibers cover the patella on all sides and in the region of its lower pole form their own patellar ligament.

The patella is located in a small depression, held in place by the quadriceps tendons and supporting ligaments (external and internal). The femoral condyles play a certain role in limiting the mobility of the patella.

Predisposing factors

The likelihood of patellar dislocation increases with a shallow patellar cavity, a poorly developed lateral femoral condyle, and a violation of the relationship between the axis of the quadriceps muscle and the patellar ligaments. Usually, until the moment of injury, these anatomical features do not appear in any way and go unnoticed.

Classification of patellar dislocation

In traumatology, acquired (traumatic) and congenital dislocations of the patella are distinguished.

Depending on the prescription of the injury, acute and chronic dislocation of the patella is distinguished. If the dislocation occurs repeatedly, they speak of a habitual dislocation.

According to the direction of displacement there are:

• lateral dislocations of the patella (external and internal);
• torsion (rotational) dislocations, in which the patella turns around its vertical axis;
• vertical dislocations, in which the patella rotates around its horizontal axis and wedged into the joint space between the tibia and femur.

Most often, external dislocation of the patella is observed, less often - internal dislocation. Torsion and vertical dislocations of the patella are extremely rare.

As a rule, the cause of dislocation of the patella is direct trauma (fall on the knee joint, side impact to the patella), combined with contraction of the quadriceps muscle.

Lateral patellar dislocation usually occurs with the lower leg in extension. When bending at the knee joint, lateral dislocation is practically impossible, since the kneecap is tightly pressed against the intercondylar surface of the femur.

In rare cases, with a bent lower leg, a vertical dislocation of the patella is possible.

Symptoms of a luxated patella

Acute traumatic dislocation of the patella is accompanied by severe pain. The knee joint is slightly bent, enlarged in volume, expanded in the transverse direction (with lateral dislocations).

Active movements are impossible, passive movements are painful and severely limited. The direction and degree of displacement of the patella is determined by palpation.

With complete dislocation, the patella is located outward from the lateral condyle of the femur; with incomplete dislocation, it is located above the lateral condyle.

Sometimes a traumatic dislocation of the patella can be reduced on its own.

Patients in such cases report an episode of sharp pain in the leg, which was accompanied by a feeling of buckling and displacement in the knee.

After a self-reduced patellar dislocation, slight or moderate swelling in the knee joint area is observed. Hemarthrosis (accumulation of blood in the knee joint) is possible.

Diagnosis of patellar dislocation

The diagnosis of patellar dislocation is made by a traumatologist based on the characteristic history, clinical picture and radiographic data.

The most informative are comparative radiographs of both patellas, taken with the tangential direction of the X-rays from the front and from top to bottom or from bottom to top.

The basis for diagnosing habitual dislocation is repeated displacement of the patella that occurs without significant traumatic impact.

Habitual and chronic patellar dislocations may be an indication for an MRI of the knee joint.

When deciding whether the operation is advisable, a diagnostic arthroscopy of the knee joint is performed.

Treatment of patellar luxation

Acute patellar dislocation is usually treated conservatively. The dislocation is reduced under local anesthesia.

The limb is flexed at the hip joint (to relieve tension on the quadriceps tendons) and extended at the knee joint.

Then the patella is carefully displaced until the dislocation is eliminated and a plaster cast is applied.

After reduction, a control x-ray is required to confirm the reduction of the dislocation and to identify bone and cartilage bodies, which are sometimes formed during trauma.

In case of acute dislocation of the patella, immobilization for a period of 4-6 weeks is indicated. Massage and physiotherapy are carried out under the supervision of a physiotherapist without removing the splint.

Full weight bearing on the leg is allowed one month after the injury.

Surgical treatment of acute dislocation of the patella is carried out when osteochondral bodies are detected and there is a high probability of repeated dislocations due to changes in the knee joint.

Chronic and habitual dislocations of the patella are an indication for surgical treatment. After surgery, immobilization is indicated for a period of 4-6 weeks.

Full range of motion in the knee joint is allowed after 8-10 weeks.

Source: http://www.krasotaimedicina.ru/diseases/traumatology/patellar-dislocation

Patella dislocation

The patella or kneecap can be a source of pain in the knee joint.

The joint between the femur and the patella is called the patellofemoral joint. Unless the anatomy of the patellofemoral joint is altered, a very large amount of force is required for patellar dislocation to occur.

However, if there is any structural anomaly in the patellofemoral joint, the likelihood of patellar dislocations increases dramatically.

As a result of improper functioning of the patellofemoral joint, increased wear of the cartilage of the patella and femur occurs, and subchondral fractures can also form.

A painful condition in which there is loss of cartilage in a joint is called arthrosis of the patellofemoral joint.

Problems in the patellofemoral joint can be present in people of all ages. This article will help you understand what problems can occur in the patellofemoral joint and how they can be solved.

The patella is an oval-shaped bone with two articular surfaces separated by a vertical ridge.

The patella is located on the front surface of the knee joint. The patella moves in the intercondylar groove of the femur. The joint formed by the patella and the femur in medicine is called patellofemoral.

The patella is a unique bone that is part of the extensor apparatus of the knee joint. The patella is connected to the quadriceps muscle by the tendon of the same name, and to the tibia by its own patellar ligament.

When the 4-head muscle of the thigh is tense, its tendon exerts traction on the patella, the latter, in turn, on its own patellar ligament and tibia, thereby extending the knee.

The surface of the patella facing the femur is covered with smooth and slippery cartilage called articular cartilage. This cartilage allows the patella to slide relative to the femur in the intercondylar groove.

The lateral and medial heads of the quadruple femoris muscles and the patellofemoral and patellotibial ligaments also attach to the patella and help control its position in the intercondylar groove.

The cooperative action of muscles and ligaments keeps the patella from dislocating.

One of the most common causes of patellofemoral joint pain is impaired movement of the patella in the intercondylar groove.

The heads of the quadriceps muscle and ligaments help center the patella in the intercondylar groove of the femur during movement.

For various reasons, there may be an imbalance in the pull of the muscles, causing one of the heads to pull on the patella more than the other.

This, in turn, causes greater pressure from the patella on the articular cartilage of the intercondylar groove on one side compared to the other. Constant excess pressure leads to damage to articular cartilage.

Another cause of problems in the patellofemoral joint is a structural abnormality.

Some people are born with a greater than normal angle between their femur and tibia. This problem is more common in women.

In medicine, this condition is called valgus deformity of the knee joint.

In cases where the angle increases, the vector of traction of the muscles and ligaments acting on the patella changes, so when moving, the patella tends to dislocate outward from the groove.

In this case, the cartilage in the outer part of the intercondylar groove of the femur experiences more pressure during movements. If such an effect occurs for a long time, softening and then destruction of the cartilage begins first. This phenomenon is called chondromalacia of the patella.

Finally, dislocation of the patella can occur if one of the walls of the intercondylar groove, usually the outer one, is less developed than the inner one, or the depth of the intercondylar groove is not sufficient to keep the patella from dislocation. In these cases, the patella also tends to dislocate from the joint. With repeated dislocations, rapid degeneration of the cartilage of the femur and patella occurs and causes persistent severe pain in the patient. It is worth noting that dislocations and subluxations tend to recur as the surrounding patellar suspensory ligaments become stretched or damaged and the femoral condyles wear down.

People whose patella is too high relative to the femur are also at risk. In this part of the femur, the intercondylar groove is not pronounced, so even a slight impact on the patella causes dislocation.

A subchondral fracture occurs when the patella jumps over the femoral condyle during dislocation, at which point a piece of bone or cartilage may break off from the femur or patella. A fragment of bone or cartilage remains in the cavity of the knee joint and causes blockages.

Patellar dislocations often occur in women between 20 and 30 years of age and in men under 40 years of age. Most often, a dislocated patella spontaneously reduces when the knee joint is extended. If the dislocation is not eliminated and the patient is taken to the hospital, eliminating the dislocation does not cause any difficulties.

Provided that this is the patient’s first case of dislocation, he is most likely to report that he felt “the knee flew out to the side” or “dislocated.” The patient also notes a clearly visible joint deformity and swelling around the kneecap.

During the examination, the doctor should always also identify damage to the articular cartilage of the patella and femur, which often accompany patellar dislocation.

With dislocation, hemarthrosis is often detected. Hemarthrosis is bleeding of blood into a joint.

If the joint cartilage or bone is damaged, fat droplets will appear in the blood when the joint contents are aspirated.

Patella dislocation in most cases occurs on the lateral (outer) side. This damages the medial stabilizers of the patella.

Gentle palpation with your fingertips in the joint area allows you to determine the location of the damage.

Usually, retraction of soft tissues is detected along the medial edge of the patella.

This region is where the medial patellofemoral ligament (MPFL) and vastus medialis muscle attach to the patella.

With dislocations, these structures are more likely to rupture. Also, upon palpation and loads on the patella, its increased mobility is determined, more to the outside.

The patient is usually taken to the hospital with the dislocation repaired. The dislocation spontaneously reduces in the prehospital stage when the leg is extended.

When the patient is admitted to the hospital, an X-ray of the joint is performed.

Radiographs can reveal concomitant subchondral damage; rarely, if the dislocation has not been eliminated earlier, the images reveal dislocation of the patella from the intercondylar groove of the femur.

Patients with habitual dislocation most often report several dislocations in the past. The patient's previous dislocations were accompanied by acute pain, swelling, and hemarthrosis.

During the examination, the doctor pays attention to the deformation of the lower limb and conducts special tests, the purpose of which is to determine the degree of mobility of the patella.

Some stress tests cause the patient to feel “anxious” or “fear” that the patella will dislocate during the test.

X-ray examination is one of the most important in the diagnosis of diseases and injuries of the patellofemoral joint. In some cases, MRI is used to diagnose patellofemoral joint injuries.

The advantage of this method is that it is more informative and painless.

Recent advances allow doctors to see articular cartilage and determine whether it is damaged or not. It is important that this study does not require the injection of dyes into the joint.

In some cases, arthroscopy may be used to make a definitive diagnosis.

Arthroscopy is a surgery that involves placing a small optical instrument inside a joint, allowing the surgeon to directly see the structures inside the joint.

An arthroscope allows the doctor to see the condition of the articular cartilage on the inner surface of the kneecap.

The vast majority of patellofemoral joint problems are diagnosed without surgery, and arthroscopy is commonly used to treat problems identified by other examinations.

Increased patellar mobility is often found in people with recurrent patellar luxation.

Some of them experience vague pain in the knee joint, sometimes around or along the inner edge of the patella.

Typically, people who have patellofemoral joint problems experience pain when walking down stairs.

Sitting for long periods of time with the knee joint bent, such as in a car or movie theater, can also cause pain. Often the patient can hear a crunching sound when moving the knee. If the cartilage wears down significantly, inflammation in the joint can occur and fluid can even accumulate.

If conservative treatment does not improve your condition, surgical treatment may be offered. There are various methods to diagnose and successfully treat problems associated with the patella. In some particularly complex cases, a combination of these may be required.

Arthroscopy is one of the most effective ways to treat diseases and injuries of the knee joint.

By directly examining the articular surface of the patella and femur, the surgeon can assess the location and degree of cartilage wear.

The doctor can also observe how the patella moves in the notch of the femur during movements of the knee joint and evaluate the degree of displacement (subluxation) of the patella.

If the articular cartilage of the patella is damaged, the doctor can use a special tool to treat the damaged areas of the cartilage, smooth out the roughness of the cartilage, which can reduce pain.

Arthroscopy is performed through the smallest possible skin punctures, which achieves excellent cosmetic results.

During arthroscopy, it is possible to eliminate the consequences of patellar dislocation. Often, with repeated dislocations, pieces of cartilage break off into the joint cavity.

Moving inside the joint, loose intra-articular bodies damage the structures of the joint and can block it.

In patients with habitual dislocation, the patella is in a state of subluxation to the lateral side. During arthroscopic surgery, it is possible to perform a lateral release.

The essence of the operation is to dissect the ligaments along the outer edge of the patella, thereby shifting the patella from a state of subluxation to a normal position to the center of the groove of the femur, and the load on the cartilage is reduced.

Also, during arthroscopy, the tissue along the inner edge of the patella can be tightened and capsulorrhaphy can be performed (Yamamoto operation).

Performing a lateral release and a Yamamoto procedure balances the pull of the quadriceps muscle and thereby evenly distributes the pressure on the patellar cartilage.

In some cases of severe patellar displacement, lateral release and the Yamamoto procedure may not be sufficient.

In addition to lateral release, surgery may be performed to strengthen the patellar tendon ligament (IPFL).

There are various operations that achieve this goal.

In some of them, a graft is formed, which is attached on one side to the edge of the patella, and on the other to the femur. Thanks to this operation, the patella does not have the opportunity to move into a position of dislocation or subluxation during movements in the knee joint.

Correct sliding of the patella in the center of the groove of the femur is achieved at all angles of flexion in the knee joint. The result of the operation can be a significant reduction in pain and crunching in the joint, as well as a reduction in the risk of repeated dislocations of the patella.

Arthroscopic surgeries are usually performed under spinal anesthesia. You will need to spend one or two nights in the hospital.

In our clinic, we widely use arthroscopy and other minimally invasive methods for treating knee joint pathologies.

Operations are carried out on ultra-modern medical equipment using high-quality and proven consumables and implants from major global manufacturers.

However, the result of the operation depends not only on the equipment and quality of the implants, but also on the skill and experience of the surgeon. The specialists of our clinic have extensive experience in treating injuries and diseases of this localization for many years.

Source: http://xn----7sbahghg9bhvbcaodkwfh.xn--p1ai/vyvih-nadkolennika

Patella dislocation: treatment, symptoms and first aid

Traumatic injury in the form of patellar dislocation occurs relatively infrequently, according to statistics in only 0.4-0.6% of cases of all traumatic injuries.

However, the injury causes many problems: both for the attending physician and the patient, as it causes difficulties in treatment and rehabilitation, as well as a high risk of recurrence.

Structure

The patella is a small bone that belongs to the sesamoid class.

Sesamoid bones are calcified and degenerated areas of the ligamentous apparatus, which are located next to the joint.

For example, there are sesamoid bones of the foot, located next to numerous small ones. The patella is the largest bone of the sesamoid generation.

It is located in front of the knee joint.

It is a flat bone that has two surfaces: the articular or internal, facing the outer surface of the articular capsule of the knee joint, it is covered with hyaline cartilage tissue, and the external. The bone formation has a triangular shape, with the base facing upward.

The patella is fixed using ligaments and tendons. Attached to the top of the patella are the tendons of the quadriceps femoris: rectus and intermedius, vastus lateralis and vastus medialis. From below it is connected to the tibia by the straight ligament. Education is mobile and performs the following functions:

1. Protective: protects the joint capsule and acts as a shield;
2. Block: does not allow the knee joint to hyperextend;
3. Stabilizing: maintains the shape of the knee joint.

The prepatellar bursa is adjacent to the outer surface of the cup, thanks to which movement occurs. The suprapatellar bursa is located under the junction with the quadriceps femoris muscle, and the infrapatellar bursa is located under the apex and straight ligament.

Varieties

Patella luxation is divided into:

• Congenital dislocation. Diagnosed in children in the first 3 years of life, the incidence is 3 times more common in the male population. The pathology is characterized by “breakage” during intrauterine development during the period of embryogenesis, is accompanied by a disturbance in neuromuscular development and is often combined with deformation in the condyles of the femur. The child’s first complaints arise in preschool and primary school age;
• Acquired or traumatic. Occurs as a result of the impact of a traumatic factor on the joint with a force exceeding the compensatory capabilities of the ligamentous apparatus;
• Habitual luxation of the patella. The frequency of occurrence in humans is 2 or more times a year.

It proceeds according to the type of acute or chronic process. Old-fashioned is characteristic of habitual pathology. Depending on the mechanism by which the injury occurred, the disease is divided into types:

1. Vertical. There is a horizontal migration of the sesamoid bone and its entry into the interarticular space, breaking through the capsule;
2. Rotary. The injury causes the kneecap to rotate around its axis;
3. Side. The impact force occurs on the side of the cup, or when falling in an extended position of the leg. It is also divided into:
   • Lateral dislocation;
   • Medial dislocation.

Also, depending on the damage to the skin, open or closed dislocation is possible.

First aid: what to do

If you suspect a dislocated patella, you should:

1. Call an ambulance team to transport the victim to a specialized medical facility;
2. Immobilize the lower affected limb in a straight position to prevent progression of the disease and prevent greater trauma;
3. Apply ice or a piece of frozen meat previously wrapped in cloth. This will reduce swelling and inflammation due to vasospasm when exposed to cold;
4. If possible, numb the pain with intramuscular administration of an analgesic: Ketanov, Dexalgin, Spazmalgon, etc. Oral administration has a less pronounced effect.

Which doctor should I go to?

Pathology is under the full competence of the traumatologist. Thus, the injured patient is taken to a 24-hour emergency room.

In case of chronic or habitual dislocation of the knee cap, the patient is observed by a traumatologist in the clinic.

With frequent relapses of habitual dislocation, the patient can straighten the cup on his own, although it is still better to consult a doctor!

Symptoms and signs

With congenital dislocation of the patella, the lesion is often unilateral. The calyx, upon examination, is displaced outward. On a direct x-ray, the patella is reduced in size, and its lateroposition is noted in comparison with the healthy side.

The cup moves (changes its position) during flexion and extension: most often, when the knee is fully extended, it returns to its normal position, and when flexed, it moves. Gradually, as the child grows, the clinical manifestations worsen: blocks form in the joint, while movements are impossible and the child falls when walking.

Pain occurs due to regular trauma to the ligamentous and articular components, bursitis develops, and if blood vessels are damaged, hemorrhages into the cavity of the knee joint. In acute dislocation, the following signs are observed:

• Severe acute pain, which makes movement impossible;
• Visible deformity of the left or right knee;
• Due to swelling and inflammation, there is a significant increase in the volume of the joint, local hyperthermia and hyperemia of the skin;
• Absence of pulsation of the arteries below the knee (a bad diagnostic sign, since it indirectly indicates damage to the arterial vessel; with prolongation of therapy, irreversible ischemic changes in the lower leg are possible);
• Paresthesia or hypoesthesia of the lower leg: numbness, heat or cold, itching (indicative of damage to the peripheral nerve plexuses).

Clinical features of habitual dislocation usually indicate a subacute course of the disease:

1. Discomfort when walking;
2. Drawing fighting sensations;
3. Knee deformity;
4. Slight increase in volume due to edema.

Treatment

Treatment of a dislocated kneecap is carried out by a traumatologist. Depending on the type of fracture and its severity, management tactics are chosen: conservative or surgical.

Conservative treatment consists of repositioning the cup. Then fixation is carried out until healing with plaster.

If necessary, a joint puncture is first performed in order to drain the accumulated effusion or blood if the vascular component is damaged.

Operation

It is carried out using the arthroscopic method: using optical endoscopic equipment. The most common operation is capsulorrhaphy.

Fundamentally, capsulorrhaphy consists of fixing the upper part of the patella with Yamomoto sutures to the capsule of the knee joint.

This operation is effective for the treatment of habitual dislocation, as it stabilizes the movements of the patella and the impact of the quadriceps muscle, due to which the impact on the cartilaginous component is distributed. In some severe cases, additional fixation of the ligamentous apparatus is resorted to

At home

Then the limb is bent at the hip at a right angle, the knee is fully extended.

By pressing the patella with fingers, the sesamoid bone is adjusted, and the patient feels a “lumbago”.

Rehabilitation and recovery

Rehabilitation measures are carried out after absolutely any type of injury to the patella, including after the usual dislocation of the kneecap. The duration of rehabilitation lasts from two months to a year, depending on the severity of the lesion. Rehabilitation includes:

1. Massage. It is carried out immediately after removing the bandage, the main task is to improve blood circulation, increase reserve regenerative capabilities, restore and prevent muscle contractures.

2. Passive movements of the knee joint. Performed by a physiotherapist, he carefully passively bends and straightens the knee, and rotates the shin with rotational movements. This causes discomfort for the patient, sometimes painful, so pain relief is sometimes required before the procedure.

3. Physiotherapy. It is carried out using various combinations of techniques:

• Electrotherapy. Electrophoresis with calcium, local anesthetics, nicotinic acid - thereby improving lymphatic drainage activity, blood circulation, and accelerating regeneration processes;
• Thermal applications. They use paraffin or ozokerite and apply it topically to the affected area, which also improves blood flow and eliminates congestion;
• Vibromassage. Allows you to reach the deep structures of the knee joint, prevents the development of chronic arthrosis;
• Dorsenvalization. Electrical discharges reduce inflammation, pain, help reduce swelling and other types of physical therapy.

4. Exercise therapy. After the doctor has developed the leg, courses of therapeutic exercises begin. The patient independently tries to make movements, a set of exercises is selected to strengthen the muscles of the lower leg and thigh with minimal load on the knee.

How long to walk in a cast

The duration of application of a plaster cast depends on the severity and complexity of medical procedures, the patient’s premorbid background, his age, concomitant pathology and other factors. On average, you need to wear a cast for a period of at least 6 weeks.

With surgical intervention for a habitual dislocation, prolongation of up to 8 weeks is possible. If the patient is elderly with signs of osteoporotic and osteochondrosis changes, then the cast can last up to 2 months.

Consequences

With timely and correct treatment of patellar dislocation, the consequences can most often be avoided. With incorrect treatment tactics or prolongation of therapy, a transition to the chronic stage is possible.

Chronic arthrosis of the knee joint develops, aggravation of which can occur with minor trauma, meteorological changes, during colds and decreased immunity.

May be accompanied by intra-articular effusion, limited range of motion, etc. The most serious complication is the transition of the acute form into a habitual dislocation. This prolongs treatment and is an indication for surgery.

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Traumatic injury in the form of patellar dislocation occurs relatively infrequently, according to statistics in only 0.4-0.6% of cases of all traumatic injuries. However, the injury causes many problems: both for the attending physician and the patient, as it causes difficulties in treatment and rehabilitation, as well as a high risk of recurrence.

Structure

The patella is a small bone that belongs to the sesamoid class. Sesamoid bones are calcified and degenerated areas of the ligamentous apparatus, which are located next to the joint. For example, there are sesamoid bones of the foot, located next to numerous small ones. The patella is the largest bone of the sesamoid generation.

It is located in front of the knee joint. It is a flat bone that has two surfaces: the articular or internal, facing the outer surface of the articular capsule of the knee joint, it is covered with hyaline cartilage tissue, and the external. The bone formation has a triangular shape, with the base facing upward.

The patella is fixed using ligaments and tendons. Attached to the top of the patella are the tendons of the quadriceps femoris: rectus and intermedius, vastus lateralis and vastus medialis. From below it is connected to the tibia by the straight ligament. Education is mobile and performs the following functions:

1. Protective: protects the joint capsule and acts as a shield;
2. Block: does not allow the knee joint to hyperextend;
3. Stabilizing: maintains the shape of the knee joint.

The prepatellar bursa is adjacent to the outer surface of the cup, thanks to which movement occurs. The suprapatellar bursa is located under the junction with the quadriceps femoris muscle, and the infrapatellar bursa is located under the apex and straight ligament.

Varieties

Patella luxation is divided into:

• Congenital dislocation. Diagnosed in children in the first 3 years of life, the incidence is 3 times more common in the male population. The pathology is characterized by “breakage” during intrauterine development during the period of embryogenesis, is accompanied by a disturbance in neuromuscular development and is often combined with deformation in the condyles of the femur. The child’s first complaints arise in preschool and primary school age;
• Acquired or traumatic. Occurs as a result of the impact of a traumatic factor on the joint with a force exceeding the compensatory capabilities of the ligamentous apparatus;
• Habitual luxation of the patella. The frequency of occurrence in humans is 2 or more times a year.

It proceeds according to the type of acute or chronic process. Old-fashioned is characteristic of habitual pathology. Depending on the mechanism by which the injury occurred, the disease is divided into types:

1. Vertical. There is a horizontal migration of the sesamoid bone and its entry into the interarticular space, breaking through the capsule;
2. Rotary. The injury causes the kneecap to rotate around its axis;
3. Side. The impact force occurs on the side of the cup, or when falling in an extended position of the leg. It is also divided into:
   • Lateral dislocation;
   • Medial dislocation.

Also, depending on the damage to the skin, open or closed dislocation is possible.

First aid: what to do

If you suspect a dislocated patella, you should:

1. Call an ambulance team to transport the victim to a specialized medical facility;
2. Immobilize the lower affected limb in a straight position to prevent progression of the disease and prevent greater trauma;
3. Apply ice or a piece of frozen meat previously wrapped in cloth. This will reduce swelling and inflammation due to vasospasm when exposed to cold;
4. If possible, numb the pain with intramuscular administration of an analgesic: Ketanov, Dexalgin, Spazmalgon, etc. Oral administration has a less pronounced effect.

Which doctor should I go to?

Pathology is under the full competence of the traumatologist. Thus, the injured patient is taken to a 24-hour emergency room. In case of chronic or habitual dislocation of the knee cap, the patient is observed by a traumatologist in the clinic. With frequent relapses of habitual dislocation, the patient can straighten the cup on his own, although it is still better to consult a doctor!

Symptoms and signs

With congenital dislocation of the patella, the lesion is often unilateral. The calyx, upon examination, is displaced outward. On a direct x-ray, the patella is reduced in size, and its lateroposition is noted in comparison with the healthy side.

The cup moves (changes its position) during flexion and extension: most often, when the knee is fully extended, it returns to its normal position, and when flexed, it moves. Gradually, as the child grows, the clinical manifestations worsen: blocks form in the joint, while movements are impossible and the child falls when walking.

Pain occurs due to regular trauma to the ligamentous and articular components, bursitis develops, and if blood vessels are damaged, hemorrhages into the cavity of the knee joint. In acute dislocation, the following signs are observed:

• Severe acute pain, which makes movement impossible;
• Visible deformity of the left or right knee;
• Due to swelling and inflammation, there is a significant increase in the volume of the joint, local hyperthermia and hyperemia of the skin;
• Absence of pulsation of the arteries below the knee (a bad diagnostic sign, since it indirectly indicates damage to the arterial vessel; with prolongation of therapy, irreversible ischemic changes in the lower leg are possible);
• Paresthesia or hypoesthesia of the lower leg: numbness, heat or cold, itching (indicative of damage to the peripheral nerve plexuses).

Clinical features of habitual dislocation usually indicate a subacute course of the disease:

1. Discomfort when walking;
2. Drawing fighting sensations;
3. Knee deformity;
4. Slight increase in volume due to edema.

Treatment

Treatment of a dislocated kneecap is carried out by a traumatologist. Depending on the type of fracture and its severity, management tactics are chosen: conservative or surgical. Conservative treatment consists of repositioning the cup. Then fixation is carried out until healing with plaster. If necessary, a joint puncture is first performed in order to drain the accumulated effusion or blood if the vascular component is damaged.

Operation

If ineffective, the patient is recommended to undergo surgery. It is carried out using the arthroscopic method: using optical endoscopic equipment. The most common operation is capsulorrhaphy. Fundamentally, capsulorrhaphy consists of fixing the upper part of the patella with Yamomoto sutures to the capsule of the knee joint.

This operation is effective for the treatment of habitual dislocation, as it stabilizes the movements of the patella and the impact of the quadriceps muscle, due to which the impact on the cartilaginous component is distributed. In some severe cases, additional fixation of the ligamentous apparatus is resorted to

At home

At home, therapy is possible only for habitual dislocation; acute conditions require specialized medical care. Anesthesia is first performed by intramuscular injection of an anti-inflammatory agent.

Then the limb is bent at the hip at a right angle, the knee is fully extended. By pressing the patella with fingers, the sesamoid bone is adjusted, and the patient feels a “lumbago”. After which it is recommended to immobilize the limb using a tight elastic bandage or a rigid orthosis.

Rehabilitation and recovery

Rehabilitation measures are carried out after absolutely any type of injury to the patella, including after the usual dislocation of the kneecap. The duration of rehabilitation lasts from two months to a year, depending on the severity of the lesion. Rehabilitation includes:

1. Massage. It is carried out immediately after removing the bandage, the main task is to improve blood circulation, increase reserve regenerative capabilities, restore and prevent muscle contractures.

2. Passive movements of the knee joint. Performed by a physiotherapist, he carefully passively bends and straightens the knee, and rotates the shin with rotational movements. This causes discomfort for the patient, sometimes painful, so pain relief is sometimes required before the procedure.

3. Physiotherapy. It is carried out using various combinations of techniques:

• Electrotherapy. Electrophoresis with calcium, local anesthetics, nicotinic acid - thereby improving lymphatic drainage activity, blood circulation, and accelerating regeneration processes;
• Thermal applications. They use paraffin or ozokerite and apply it topically to the affected area, which also improves blood flow and eliminates congestion;
• Vibromassage. Allows you to reach the deep structures of the knee joint, prevents the development of chronic arthrosis;
• Dorsenvalization. Electrical discharges reduce inflammation, pain, help reduce swelling and other types of physical therapy.

4. Exercise therapy. After the doctor has developed the leg, courses of therapeutic exercises begin. The patient independently tries to make movements, a set of exercises is selected to strengthen the muscles of the lower leg and thigh with minimal load on the knee.

How long to walk in a cast

The duration of application of a plaster cast depends on the severity and complexity of medical procedures, the patient’s premorbid background, his age, concomitant pathology and other factors. On average, you need to wear a cast for a period of at least 6 weeks.

With surgical intervention for a habitual dislocation, prolongation of up to 8 weeks is possible. If the patient is elderly with signs of osteoporotic and osteochondrosis changes, then the cast can last up to 2 months.

Consequences

With timely and correct treatment of patellar dislocation, the consequences can most often be avoided. With incorrect treatment tactics or prolongation of therapy, a transition to the chronic stage is possible. Chronic arthrosis of the knee joint develops, aggravation of which can occur with minor trauma, meteorological changes, during colds and decreased immunity.

May be accompanied by intra-articular effusion, limited range of motion, etc. The most serious complication is the transition of the acute form into a habitual dislocation. This prolongs treatment and is an indication for surgery.

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Thank You for rating this article. Published: June 14, 2017