Elbow dislocation

Introduction Dislocation of the elbow joint is the first of the dislocation of the whole body. It is more common in young adults. When falling, the upper limbs are abducted and the palms are on the ground, which can cause dislocation of the elbow joint. Dislocation of the iliac crest and the upper end of the ulna can occur at the same time as the temporal or ulnar displacement, or the fracture or ulnar nerve injury. Elbow joint dislocation in joint dislocation, elbow joints occupy the first position, according to dislocation, can be divided into anterior dislocation, posterior dislocation and lateral dislocation, of which post dislocation is the most common. Due to the complex type of elbow dislocation, often combined with other structural injuries in the elbow, attention should be paid to the diagnosis and treatment to prevent misdiagnosis.

Cause

(1) Causes of the disease

Mostly indirect violence, and occasional direct violence can also cause injury.

(two) pathogenesis

Dislocation of the elbow is mainly caused by indirect violence. The elbow is the coupling structure between the forearm and the upper arm. The violent conduction and leverage are the basic external forces that cause dislocation of the elbow joint.

1. Dislocation of the elbow joint This is the most common type of dislocation, with adolescents as the main target. When falling, the palm of the hand touches the ground, the elbow joint is fully extended, the forearm is rotated, and the elbow joint is overextended due to human gravity and ground reaction force. The top of the olecranon violently impacts the olecranon socket at the lower end of the humerus, which forms the fulcrum of force. The external force continues to strengthen the anterior partial tear of the tibialis anterior and elbow joint capsules attached to the condyle, causing the ulnar olecranon to shift backward, while the lower end of the humerus is displaced forward. Because the inner and outer humerus of the lower end of the humerus forming the elbow joint is wide and thick, the front and back are flat and thin, and the collateral ligament is strengthened on the side. However, if the lateral dislocation occurs, the avulsion fracture of the internal and external ankle is easy to occur.

2. The dislocation of the elbow joint before dislocation is rare, and often combined with olecranon fracture. The cause of the damage is mostly direct violence, such as direct impact on the elbow or impact of the elbow on the ground in the flexion position, resulting in fracture of the olecranon and proximal dislocation of the ulna. This type of injury to the elbow soft tissue injury is more serious.

3. Lateral dislocation of the elbow joint is more common in adolescents. When the elbow is subjected to conduction violence, the elbow joint is in an inversion or valgus position, causing the collateral ligament and joint capsule of the elbow joint to tear. The lower end of the tibia can be moved to the temporal or ulnar side (ie, the joint capsule rupture). Bit. Due to strong internal and external valgus, due to the violent contraction of the forearm extension or flexor muscles, the internal and external iliac avulsion fractures are caused, especially in the humerus. Sometimes the fracture piece can be embedded in the joint space.

4. Elbow joint dislocation and dislocation This type of dislocation is extremely rare. Because the upper and lower conduction violence is concentrated on the elbow joint, the forearm is excessively pronation, the annular ligament and the proximal interosseous membrane of the ulna and radius are cleft, causing the humeral head to dislocate to the front and the proximal ulna dislocation. The lower end of the humerus is inserted between the ends of the two bones.

an examination

Related inspection

Visual examination of bone and joint and soft tissue CT examination with synovial fluid

diagnosis

1. History of trauma, the most common to fall to the palm of your hand.

2. Clinical manifestations The affected area is swollen, painful, and inactive. The patient holds the affected side of the forearm with a healthy hand. The elbow joint is in a semi-extended position, and the elbow is not straight when the passive movement is performed. The emptiness behind the elbow can be touched into the depression. The three-point relationship between the elbows is completely destroyed and the normal relationship is lost.

3. Imaging examination of the positive and lateral X-ray examination can confirm the diagnosis, and can determine the type of joint dislocation, and whether the fracture and displacement are combined. CT and 3D reconstruction can obtain accurate fracture and dislocation information.

Differential diagnosis

Elbow joint can not flex: When the elbow flexion of the elbow or the joint dislocation, the elbow joint can not flex, the forearm is straight and drooping, and the upper limb can not do the life movement of the flexion forearm, such as not washing the face, eating, etc. Immediately after the dislocation of the elbow, the patient feels severe pain and cannot flex the elbow joint, and swelling can occur.

The varus angle of the elbow joint is increased: the elbow varus elbow joint extension position is significantly increased. The varus angle of the elbow joint is obviously increased, reaching 15°35°. The triangular joint of the elbow is changed, and the distance between the external malleolus and the olecranon is widened. Generally, the elbow joint activity is normal, but the muscle strength is weakened to varying degrees. The elbow varus angle can be measured from the radiograph.

Elbow joint deformity: The elbow joint is one of the most stable joints of the human body. The stability of the elbow joint depends on the integrity of the joint structure. The maximum flexion and extension can reach 160°, the pre-rotation can reach 85°, and the supination is about 80. °, the pulley and the long axis of the humerus at 6 ° valgus angle, and the intercondylar axis with an internal rotation angle of 5 ° ~ 7 °, elbow joint flexion and extension axis in front of the midline of the humerus and the humeral shaft to form an angle of 40 °. Elbow joint dislocation, fracture and other reasons can lead to elbow joint deformity.

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