traumatic posterior dislocation of the shoulder
Introduction
Introduction to traumatic shoulder dislocation Dislocation of the shoulder joint is less common. One of the reasons is that there is strong muscle group protection behind the shoulder joint, which is difficult to be pulled backwards. Even after dislocation, it is easy to retract due to the tensile stress of the posterior muscle group, so it is rarely clinically see. basic knowledge The proportion of sickness: 0.01% Susceptible people: no specific people Mode of infection: non-infectious Complications: vascular injury
Cause
Causes of traumatic shoulder dislocation
(1) Causes of the disease
Indirect violence or direct violence can cause dislocation.
(two) pathogenesis
1. Direct violence: refers to the force from the front of the joint capsule directly acting on the humeral head to cause posterior dislocation, which is more common when the house collapses, and more complicated with the fracture of the humeral neck. One of the authors encountered this case in the Xingtai earthquake. In this case, this may be related to the fact that the local houses are mostly made of wooden beam flat roof construction.
2. Indirect violence: When the shoulder joint falls in the inner rotation position of the hand, the humeral head can protrude to the rear and penetrate the posterior wall of the joint capsule to escape.
Prevention
Traumatic shoulder dislocation prevention
The disease is caused by trauma directly on the palms, wrists and elbows, such as falls, falls, and emergency braking caused by the car. Therefore, pay attention to living habits, high-risk workers, such as construction workers, mining workers, and teachers and workers are likely to cause damage, and should pay attention to protect themselves during the work process. Pay attention to calmness and avoid emotional conflicts leading to the disease. Secondly, early detection, early diagnosis and early treatment are also important for the prevention of this disease.
Complication
Traumatic shoulder dislocation complications Complications, vascular injury
Fracture
(1) Large nodular fracture: about 30% to 40% with large nodular fractures. When the humeral head is dislocated forward, the humeral large nodule impacts the front of the joint and causes fracture. In most cases, the fracture block is large, and there is still a periosteum connected to the humeral head. Therefore, after the dislocation, the fracture block is also reset. A small number of reductions are poor. It is generally believed that a large nodule is displaced upward by 1 cm, which will affect the function of the shoulder. Surgery should be considered. After the operation, the upper arm was placed in the inner rotation and slightly in the position, and the forearm was slanted to the chest wall for fixation. The method of disabling the abduction and external rotation of the upper arm is unfavorable for the healing of the torn joint capsule, and there is a risk of re-dislocation or habitual dislocation.
(2) Articular hernia fracture: generally avulsion fracture, the size of the fracture block is uncertain, and it is mostly connected with the joint capsule, and some may be free bone. This part of the fracture can affect the return of the humeral head, but the most important thing is easy to develop into a habitual dislocation, so the thickness of the fracture block is more than 5 ~ 6mm and the poor reduction should be treated surgically.
(3) scapular fracture: the scapula is stable in the thick muscle, so the fracture is rare when the shoulder is damaged, and the easily generated fracture is a scapular neck fracture and a shoulder fracture.
1 scapular neck fracture: mostly caused by violence, the fracture line from the armpit to the base of the condyle, often embedding, because the violence concentrated in the scapula neck, it may not be combined with shoulder dislocation. The shape of the shoulder can be slightly squared due to the internal rotation of the humeral head, but the Dugas sign can be negative. X-ray can confirm the diagnosis. If the fracture is not heavy, use a triangle towel to suspend the shoulder or abduction bracket for 2 to 3 weeks to practice activities. Young people shift heavy and apply abduction and traction reduction.
2 Shoulder fracture: The shoulder is at the highest point of the shoulder, so direct violence from the top down and indirect violence from the bone can cause fractures. The fracture is located on the base of the acromion. It can be displaced downward due to the pulling of the deltoid muscle, which hinders the function of the shoulder joint. It should be suspended by a triangle towel to make the upper displacement. The fracture outside the shoulder joint is small because of the fracture piece. The strap is pressed and the arm is suspended with a triangle.
2. rotator cuff injury
It is a common complication of shoulder dislocation. It is often ignored because it cannot be displayed directly on the X-ray film. Occasionally in patients over the age of 40, X-ray films show anterior and posterior dislocation of the shoulder joint without a large nodular fracture of the humerus, and the possibility of rotator cuff injury should be considered. Young people can also occur during severe super abduction injuries. Should the vestibular sleeve injury be considered when the rehabilitation function is not well restored and the shoulder can not be abducted or accompanied by obvious pain. If the rotator cuff is severely damaged, its abduction function is poor, and the diagnosis is clear. Surgical exploration should be performed as soon as possible.
3. Vascular injury
Dislocation of the shoulder joint can be combined with damage to the brachial artery or vein, which is common in elderly or patients with hardening of the arteries. Too young people, such as manual reduction, can also cause damage to blood vessels.
When the radial artery passes through the lower edge of the pectoralis minor muscle, it is bound by the pectoralis minor muscle, and the position is relatively fixed. When the shoulder is abducted and externally rotated, the radial artery is pulled and strained. When the humeral head is dislocated forward, the iliac artery is displaced forward, and the outer edge of the pectoralis minor muscle acts as a fixed fulcrum, so that the iliac artery is subjected to a shear stress there, which can deform or damage the artery. Vascular injury can be complete or partial tear, or it can cause vascular embolization of endovascular damage.
Brachial artery injury manifested as swelling of the shoulder, with the axillary part as the body, the skin of the affected limb was pale or cyanotic, the skin temperature was lowered, the radial artery pulsation disappeared, and the limbs were paralyzed. In severe cases, there may be shock performance. Angiography can show the location and extent of the injury.
The diagnosis of large vessel injury should be treated as early as possible, to repair the damaged blood vessels and restore the blood circulation of the limbs. Young patients with collateral circulation supply, although not causing the entire limb necrosis, but due to insufficient blood circulation, there are still some cases of residual limb dysfunction; for elderly patients or severe arteriosclerosis, because the collateral circulation is poor, it is not appropriate Arterial ligation.
4. Nerve injury
Dislocation of the shoulder joint with nerve injury, the most common is radial nerve injury, and occasional brachial plexus injury. After the phrenic nerve is separated from the brachial plexus, it goes to the lower edge of the subscapularis muscle. After abruptly turning, it passes through the four holes and exits the armpit. It releases the muscle branch around the surgical neck of the humerus and occupies the deltoid muscle and the small round muscle. The humeral head is dislocated forward, and the humeral head and the subscapularis muscle are displaced forward, causing the phrenic nerve to be pulled and crushed. Paralysis of the deltoid muscle after sacral nerve injury, shoulder abduction dysfunction and lateral shoulder skin dysfunction.
Simple sacral nerve injury is mostly contusion or traction injury, and the humeral head can be restored after 3 to 5 months of reduction. Multiple brachial plexus injuries are generally more violent and may have permanent dysfunction.
5. Shoulder joint stiffness
Brake time after shoulder dislocation is too long, or functional exercise is not performed correctly in time, especially in middle-aged and older people, which can cause adhesion of joint capsule and muscle atrophy, resulting in limited shoulder joint activity. Therefore, for patients over 40 years old, the braking time should not be too long. After removing the fixation, the shoulder joint function should be actively exercised.
Ossifying myositis is less common in the shoulder joints and can be caused by repeated violent manual reduction or strong activity, which is one of the reasons that affect the shoulder joint activity. In addition, rotator cuff injury and radial nerve injury, due to the loss of shoulder abduction function, will also affect the recovery of shoulder function, should emphasize early correct diagnosis and early treatment.
Symptom
Traumatic shoulder dislocation symptoms Common symptoms Square shoulder deformity trauma
The clinical symptoms are not as good as the anterior dislocation. The majority of the posterior dislocation of the shoulder joint is dislocation under the shoulder. There is no obvious square shoulder deformity and elastic fixation. The range of shoulder movement is not as obvious as the anterior dislocation. X-ray anterior and posterior Often missed and reported normal, the key to prevent misdiagnosis is the possibility of shoulder dislocation needs to be considered after the dislocation, physical examination should be strict, serious and meticulous.
When the shoulder joint is dislocated, the front of the shoulder is flattened, and the protrusion of the condyle is easy to reach; the shoulder is more obvious than normal, the back of the shoulder is full, and the humeral head can be touched; the upper arm is in the neutral position or internal rotation, the internal position is closed, and the upper arm is abducted. External rotation, shoulder pain increased.
Examine
Examination of posterior dislocation of traumatic shoulder joint
No relevant laboratory tests.
Before the X-ray, the posterior slice shows that the humeral neck disappears, the shoulder and ankle are tilted forward, the elliptical shadow of the normal head lice overlaps, and the head lice are asymmetrical. If you are still not sure and suspected of dislocation, you can add the sacral position or The scapula tangential position is determined and CT helps to determine the sacral relationship.
Diagnosis
Diagnosis and diagnosis of traumatic shoulder dislocation
History of trauma, when the dislocation is flat, the front of the shoulder is flattened, and the condyle is easy to reach; the shoulder is more obvious than normal, the back of the shoulder is full, and the humeral head can be touched. There is no obvious square shoulder and elastic fixation. X-ray examination, if necessary, CT examination confirmed the diagnosis.
