Patellar dislocation

Introduction to dislocation of the humerus The humerus is the largest sesamoid in the body. Its upper edge is connected to the quadriceps tendon, the lower edge is stopped by the patellar ligament on the tibial tuberosity, and the quadriceps expansion on both sides surrounds the humerus. The medial femoral muscle ends at the upper iliac crest, and the concave surface between the posterior tibial bulge and the lower end of the femur is articular. Because the direction of the rectus femoris, the medial femoral muscle, and the lateral femoral muscle in the quadriceps is not in line with the patellar tendon, the tibia has a tendency to detach outward, but because the medial femoral muscle has an inward and upward traction force, The tibia is maintained in a normal position. There are two types of dislocation of the humerus, fresh dislocation and old dislocation (or habitual dislocation). Common violence is internal and external violence, which causes the fascia of the medial femoral musculature and the medial joint capsule to cause dislocation of the tibia. There is also violence from the outside to the inside, which causes the lateral femoral musculature and lateral joint capsule to tear, resulting in less dislocation of the humerus. basic knowledge The proportion of illness: 1-2% (the incidence rate of trauma patients is about 1-2%) Susceptible people: no specific people Mode of infection: non-infectious Complications: osteoarthritis

Causes of dislocation of the humerus

Dislocation of the humerus often occurs in direct trauma such as running (especially when cornering, turning), lateral displacement of the side of the squat (playing basketball defensive moves), or lateral impact of the knee joint. Some patients with dislocation of the humerus may have their own anatomical abnormalities, such as systemic joint capsule relaxation, high position paralysis, knee valgus (X-leg).

Damage pathology:

Most of the dislocation of the humerus is dislocated to the lateral side. After dislocation, the stable structure of the medial patellofemoral joint, including the medial support band of the patellofemoral joint, the medial femoral muscle, and the medial patellofemoral ligament, are torn, resulting in hematoma and slippage in the knee joint. Membrane; during the self-resetting process, the medial side of the tibia collides with the lateral side of the femoral condyle, causing cartilage damage or tangential fracture.

Patellar dislocation prevention

The prevention of this disease is mainly aimed at the habitual dislocation caused by traumatic causes, and avoiding trauma is the key to the prevention and treatment of this disease.

Complications of patella dislocation Complications osteoarthritis

Recurrent patellofemoral dislocation and advanced humeral subluxation may be associated with osteoarthritis.

Symptoms of dislocation of the humerus Common symptoms Joint swelling and pain Knee joint pain Knee joint weakness Knee joint clearance and pain K-angle abnormalities of knee joint effusion

The swelling of the wound is obvious, the tibia is tender, the activity is obviously limited, the knee is soft, the walking is difficult, the knee extension and the hand push can be reset. Arthroscopic examination and X-ray examination showed dislocation of the humerus.

The patient felt a sudden pain in the knee joint and could have a dislocated feeling or weakness. After the knee joint is straightened, the tibia often resets itself, and the "click" sound is often heard during the reset.

Examination of dislocation of the humerus

Film degree exam

X-ray examination of the humerus and arthroscopic examination showed that the humerus was moved up and out of the femoral condyle on the anterior segment of the humerus. The lateral humerus showed the length of the tibia and the length of the patellofemoral ligament. Under normal circumstances, the distance between the tibial tuberosity and the lower edge of the tibia (ie, the length of the patellar ligament) is consistent with the length of the tibia. If the distance is significantly greater than the length of the tibia, it is suggested that the humerus is dislocated upward.

Conventional X-ray examination of the humerus to the lateral dislocation is difficult to detect. It is advisable to take the axial position of the humerus at a position of 20-30 degrees of flexion. It can be found that there is no dislocation of the humerus. On the axial slice, the AA' line is used to connect the two parts of the femur. The second BB' line is the lateral part of the tibia. The joint line of the articular surface, the two jumpers intersect to form the tibia femoral angle. Under normal circumstances, the patellofemoral angle is open to the outside, and the humerus is dislocated outward. The two lines are parallel or the tibia angle is open to the inside. This tilting performance It shows that there is a force to pull back on the lateral side of the humerus, and the other is that the humerus leaves the normal center position at the femoral notch and shifts to the outside to become a subluxation. Sometimes both cases exist at the same time. Increased the complexity of dislocation of the humerus.

Arthroscopy

Arthroscopy mainly evaluates the degree of articular cartilage surface damage. According to the degree of degeneration of the tibial cartilage surface, which surgery is performed, it can be divided into four grades: level 1, only the cartilage becomes soft. Grade 2, with fibrotic lesions less than 1.3 cm in diameter. Grade 3, fibrotic lesions larger than 1.3 cm in diameter. Grade 4, the subchondral cortical bone has been exposed.

Physical examination

It is very important, including the patella activity check and the push and knee bend test, which can directly determine whether there is instability of the humerus.

Diagnostic diagnosis of patella dislocation

A traumatic injury to the knee joint, or a strong contraction of the quadriceps, can cause dislocation. Most patients often have dislocation. When the knee is flexed, the tibia is removed from the lateral side of the femoral condyle and naturally repositions when the knee is extended. The quadriceps atrophy, knee weakness, and easy wrestling. But there is no obvious pain.

X-ray examination of the humerus and arthroscopic examination showed that the humerus was moved up and out of the femoral condyle on the anterior segment of the humerus. The lateral humerus showed the length of the tibia and the length of the patellofemoral ligament. Under normal circumstances, the distance between the tibial tuberosity and the lower edge of the tibia (ie, the length of the patellar ligament) is consistent with the length of the tibia. If the distance is significantly greater than the length of the tibia, it is suggested that the humerus is dislocated upward.

Conventional X-ray examination of the humerus to the lateral dislocation is difficult to detect. It is advisable to take the axial position of the humerus at a position of 20-30 degrees of flexion. It can be found that there is no dislocation of the humerus. On the axial slice, the AA' line is used to connect the two parts of the femur. The second BB' line is the lateral part of the tibia. The joint line of the articular surface, the two jumpers intersect to form the tibia femoral angle. Under normal circumstances, the patellofemoral angle is open to the outside, and the humerus is dislocated outward. The two lines are parallel or the tibia angle is open to the inside. This tilting performance It shows that there is a force to pull back on the lateral side of the humerus, and the other is that the humerus leaves the normal center position at the femoral notch and shifts to the outside to become a subluxation. Sometimes both cases exist at the same time. Increased the complexity of dislocation of the humerus.

Arthroscopy mainly evaluates the degree of articular cartilage surface damage. According to the degree of degeneration of the tibial cartilage surface, which surgery is performed, it can be divided into four grades: level 1, only the cartilage becomes soft. Grade 2, with fibrotic lesions less than 1.3 cm in diameter. Grade 3, fibrotic lesions larger than 1.3 cm in diameter. Grade 4, the subchondral cortical bone has been exposed.

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