Acromioclavicular joint dislocation

　　All of these dislocations have a history of trauma. Since the acromioclavicular joint is located under the skin, it is easy to see local elevation, and the comparison between the two sides is obvious, with local pain, swelling, and tenderness; the acromioclavicular joint is a fulcrum of upper limb movement, and it occupies an important position in the function and dynamics of the scapular girdle, and is one of the indispensable joints for the abduction and elevation of the upper limb. It also participates in the flexion and extension movements of the shoulder joint. It is difficult to abduct or elevate the affected limb, and the movement of flexion and extension is also limited. Local pain intensifies, and a depression can be felt at the acromioclavicular joint during examination, and the acromioclavicular joint can be felt loose.

　　According to the degree of injury and ligament rupture, Zlotsky et al. divided it into three grades or three types. Type I: There is a slight tear of the ligament and synovial capsule fibers at the acromioclavicular joint, joint stability, mild pain, normal X-ray film, but there may be periosteal calcification shadow at the lateral end of the clavicle in the later stage. Type II: There is a tear in the acromioclavicular synovium and acromioclavicular ligament, the coracoclavicular ligament is not damaged, the lateral end of the clavicle is elevated,呈半脱位状态，there is a sensation of floating when pressed, and there may be anterior and posterior movement. X-ray film shows that the lateral end of the clavicle is higher than the acromion. Type III: Both the acromioclavicular and coracoclavicular ligaments are torn, causing obvious dislocation of the acromioclavicular joint.

     Common complications of shoulder acromioclavicular joint dislocation include the following types:

　　Chronic pain in the shoulder is rare.

　　Complications of acromioclavicular joint separation injury include instability of the scapular girdle and residual pain during shoulder movement, which may exist in both surgical and non-surgical treatments.

　　Poor healing of the acromioclavicular and coracoclavicular ligaments can lead to pain and instability during overhead movements. Insufficient scar formation, causing instability of the distal end of the clavicle, may cause pain during physical contact sports or overhead movements.

　　Other complications include the failure of internal fixation related to the acromioclavicular or coracoclavicular ligament, which may lead to recurrence of dislocation.

　　The limitation of shoulder joint activity is rare, mostly due to recurrence of dislocation and poor exercise in the later stage.

 　　According to different types of shoulder acromioclavicular joint dislocation, there are the following symptoms:

　　In the first type, there is slight swelling and tenderness at the acromioclavicular joint, and neither clinical examination nor X-ray films can find any 'subluxation' or 'true dislocation' of the lateral end of the clavicle.

　　In the second type, there are the same signs at the acromioclavicular joint, compared with the opposite side, the lateral end of the clavicle is higher, and there is a sensation of elasticity when pressed. X-ray films can show that the lateral end of the clavicle is lifted, and compared with the opposite side, at least more than 1/2 has been dislocated, but it is not a complete dislocation.

　　In the third type, the lateral end of the clavicle has been lifted above the acromion, and the local swelling is also more severe than the above two types. The activity of the shoulder joint is also affected, and any movement of the shoulder joint will worsen the pain at the acromioclavicular joint.

　　There is currently no effective preventive measure for this disease. The key to prevention and treatment is to enhance safety awareness, avoid external force injury, and early detection, early diagnosis, and early treatment. Once the disease occurs, active treatment should be carried out to prevent the occurrence of complications.

　　No related laboratory tests.

　　Through X-ray photography, the upward displacement of the outer end of the clavicle can be clearly displayed. For partial dislocation of the acromioclavicular joint, the upward displacement is slight and swelling is not obvious, making the diagnosis difficult. Sometimes it is necessary to simultaneously pull down both upper limbs to take X-ray films of both acromioclavicular joints, or have the patient stand with both hands lifting heavy objects to take anteroposterior X-ray films of both acromioclavicular joints, compare the examination, and then make an accurate diagnosis.

 　　Issues to pay attention to in the diet for acromioclavicular joint dislocation

　　1. Foods to eat for acromioclavicular joint dislocation: It is advisable to enhance nutrition, eat more protein-rich foods such as fish, eggs, and soy products, and appropriately increase calcium. Drink more water, eat more vegetables and fruits such as green vegetables, celery, and bananas.

　　2. Foods to avoid for acromioclavicular joint dislocation: Avoid spicy foods such as chili and mustard, and habits such as smoking and drinking should be戒除.

　　The treatment of acromioclavicular joint dislocation has the following methods:

　　First, treatment

　　1. Conservative treatment. For type I acromioclavicular joint dislocation, rest and hang the injured limb with a triangular bandage for 1-2 weeks is sufficient; for type II dislocation, a back strap fixation can be used. The method is that the patient stands, raises both upper limbs, first apply a plaster corset with the upper edge at the level of the nipple and the lower edge slightly below the anterior superior iliac spine, each with a metal buckle on the front and back of the corset. After the plaster dries, place a thick felt over the prominence of the outer end of the clavicle (do not place it on the acromion), and use a wide 3-5 cm belt-type canvas strap, crossing over the thick felt placed on the affected shoulder, tie the two ends of the strap to the metal buckles on the front and back of the corset with appropriate tension to compress and reduce the separated outer end of the clavicle (Figure 2). Take an X-ray film to confirm the reduction, wrap the injured limb with a triangular bandage, and fix it for 4-6 weeks. It can also be reduced under local anesthesia, with a Kirschner wire crossing fixed through the acromioclavicular joint and the acromion from the distal end of the clavicle. Hang the injured limb after surgery, and remove the steel needle after 6 weeks, and perform shoulder joint functional exercises.

　　2. Surgical treatment. For patients with complete acromioclavicular joint dislocation, i.e., type III injury, due to the rupture of the joint capsule and acromioclavicular and coracoclavicular ligaments, the stability of the acromioclavicular joint is completely lost, the effect of the above external fixation is not satisfactory. For those under 45 years old, surgical repair should be performed. Common surgical methods include open reduction and internal fixation of the acromioclavicular joint, reconstruction or fixation of the coracoclavicular ligament, excision of the outer end of the clavicle, and muscle dynamic reconstruction.

　　(1) Shoulder clavicle joint open reduction and Kirschner wire fixation: This method is suitable for type II dislocation cases. The patient is in supine position, the affected shoulder is elevated, routine disinfection and draping, after cervical interscalene block anesthesia takes effect, make an incision along the outer end of the clavicle and around the acromion, about 8-9 cm long, incise and separate the attachment of the trapezius and deltoid muscles subperiosteally, expose the acromioclavicular joint, remove bone fragments and interjoint tissue, push the upper arm upward while pressing the outer end of the clavicle downward, so that the acromioclavicular joint is reduced; fix the acromioclavicular ligament, joint capsule, and coracoclavicular ligament with two Kirschner wires crossing through the acromioclavicular joint; repair the acromioclavicular ligament, joint capsule, and coracoclavicular ligament, trim the excess Kirschner wires, bend the distal end into a hook shape and bury it subcutaneously to prevent the Kirschner wire from dislocation or slippage; finally, suture the skin, and hang the injured limb with a triangular bandage for 4-6 weeks postoperatively.

　　If this method is used to treat type III acromioclavicular dislocation, one screw should be added to fix the clavicle to the coracoid process at the same time as the above operation, so that the two bones are close together, which is conducive to the repair of the coracoclavicular ligament. The steel needle can be removed 4 to 6 weeks after surgery, and the screw can be removed one year later.

　　(2) Excision of the distal end of the clavicle and transfer of the coracoclavicular ligament: An arched incision is made in front of the coracoid process from the distal end of the clavicle. The clavicle and the joint capsule and torn ligament of the distal end are exposed above the acromioclavicular ligament. At a distance of 1 cm from the lateral side of the clavicle, a diagonal osteotomy is made. The distal end of the clavicle after excision is sutured with the coracoclavicular ligament with a mattress suture, but do not tie it immediately. Use 2 Kirschner wires to drill into the distal end of the clavicle 3 to 4 cm from the acromial end, bend the tail of the Kirschner wire into an arc and bury it under the skin. Repair the joint capsule and acromioclavicular ligament, tie the suture at the coracoclavicular ligament where the mattress suture has been made, and suture each layer layer by layer. The injured limb is suspended for 3 to 4 weeks after surgery, and functional exercises can be performed, but the upper arm cannot be raised to the horizontal position. The steel needle can be removed under local anesthesia after 8 weeks.

　　(3) Old Traumatic Acromioclavicular Dislocation: Partial dislocation of the acromioclavicular joint usually has no clinical symptoms and does not require surgical treatment. In the case of complete dislocation with symptoms such as pain, the following operations can be performed: ① Excision of the outer 1/3 of the clavicle, which can achieve satisfactory shape and function; ② Transfer of the coracoclavicular ligament to replace the coracoid ligament: cut the acromial end of the coracoclavicular ligament, suture this end into the medullary cavity of the excised distal end of the clavicle, tighten and tie; ③ Muscle dynamic transfer: after the shoulder acromioclavicular joint is incised and reduced and fixed with Kirschner wires, the coracoid process is cut off from the bottom, together with the tendons above it, transplanted upward and medially to the clavicle, and fixed with screws. The tension of the muscles attached to the coracoid process maintains the position of the clavicle after reduction.

　　II. Prognosis

　　The efficacy varies greatly depending on the type of disease, the timing of medical consultation, and the choice of treatment method. Most patients with types I and II have good efficacy, while about 10% to 15% of cases in type III patients have local sequelae, mostly manifested as pain and limited activity.