New Options for Treatment of Acromioclavicular Joint Dislocation—Three Internal Fixation Methods

Acromioclavicular joint dislocation is one of the most common injuries of the shoulder. It is more common due to direct violence and occurs more often in young people. The incidence rate accounts for about 12% of shoulder injuries. The Rockwood classification is often used, type Ⅰ and Ⅱ. There is a consensus on conservative treatment and surgical treatment for types IV to VI. However, the choice of conservative treatment or surgical treatment for Rockwood type III is still controversial. Although the conservative treatment effect of acromioclavicular joint dislocation is good, the dislocation is not reduced and will remain in the dislocated position in most patients. Additionally, some patients have sequelae of chronic instability and pain. At present, there is no recognized standard or optimal surgical procedure for the clinical treatment of acromioclavicular joint dislocation. According to statistics, there are more than 75 surgical procedures for the treatment of acromioclavicular joint dislocation, including coracoclavicular interfixation, acromioclavicular interclavicular fixation, Ligament reconstruction, distal clavicle resection, dynamic muscle transfer technique, etc.

In order to improve the success rate of acromioclavicular joint dislocation surgery, clavicle hook plate and Endobutton loop plate have become important surgical methods in the current clinical treatment of acromioclavicular joint dislocation. In recent years, with the in-depth understanding of the anatomy of the acromioclavicular joint by doctors and the continuous development of arthroscopic technology, the arthroscopic Endobutton loop steel plate has become one of the important surgical procedures for the treatment of shoulder dislocation. The Endobutton loop steel plate has stronger strength. High, in line with biomechanical characteristics, and more conducive to ensuring the stability of the acromioclavicular joint. This article will introduce in detail the clinical treatment effects of three internal fixation methods: modified loop plate Nice knot fixation, Endobutton loop plate and clavicle hook plate, and provide useful guidance for the efficient treatment of patients with acromioclavicular joint dislocation in the future.


1. Improved Loop Steel Plate Nice Knot Fixation

1. Surgical method:

After successful general anesthesia, the patient was placed in the supine position. Make a longitudinal incision about 4cm long from the coracoid process to the acromioclavicular joint to expose the acromioclavicular joint, the distal end of the clavicle and the base of the coracoid process. Make an incision about 3cm away from the acromioclavicular joint in the middle and anterior 1/3 of the clavicle, and make an incision in the medial and lateral directions respectively. Use a 2.5mm Kirschner wire to establish a bone channel on the clavicle 0.5cm, and introduce a No. 1 absorbable suture as a backup traction line. Disassemble the loop steel plate fixing wire and traction wire for later use. The traction wire of the loop plate bypasses the coracoid process base, and the double-stranded fixation wire is led out from the medial bone channel of the clavicle, the base of the coracoid process, and the lateral bone channel of the clavicle in sequence using the wire-passing technique. The two ends of the fixation wire are passed through the holes of the strip-shaped loop steel plate respectively, and the acromioclavicular joint is reduced. Use the Nice knot to gradually tighten it until the acromioclavicular joint is slightly over-reduced and then tie and fix it (Figure 1b). Drill holes on the anterolateral side of the distal clavicle, introduce No. 1 absorbable sutures, and suture the acromioclavicular ligament and joint capsule behind the acromion in an “8″ figure, rinse the incision, and suture layer by layer. Postoperative X-ray showed appropriate excessive reduction of the acromioclavicle (Fig. 1c).

Figure 1 Patient, male, 46 years old. 1a: Preoperative anteroposterior X-ray of the shoulder joint shows Rockwood type III dislocation of the right acromioclavicular joint; 1b: During the operation, the fixation line passes through the flap, and absorbable parts are reserved for repairing the coracoclavicular ligament, acromioclavicular ligament and joint capsule respectively. Line; 1c: Postoperative anteroposterior X-ray shows appropriate excessive reduction of the acromioclavicular joint.

2. Advantages:

(1) The loop steel plate system can provide a fixation strength of 1 345 N, which is far greater than the normal coracoclavicular ligament strength (580 N);

(2) There is no coracoid bone tunnel, the integrity of the coracoid is not destroyed, and there is no risk of coracoid fracture;

(3) The use of strip-shaped loop steel plates is a flat fixation, which disperses stress and reduces the risk of sinking of the loop steel plates;

(4) Research has found that the footprint area of the coracoclavicular ligament on the clavicle side is loose. The footprint areas of the cone ligament and trapezoid ligament are respectively located 30~45mm and 15~30mm away from the distal end of the clavicle. Therefore, they are approximately 3cm away from the distal end of the clavicle. Establishing a clavicular tunnel approximately 5 mm from the medial and lateral sides can perform an anatomical reconstruction of the coracoclavicular ligament;

(5) Repair the acromioclavicular joint capsule and acromioclavicular ligament to rebuild horizontal stability. Many scholars have confirmed that patients have varying degrees of horizontal instability after simple coracoclavicular ligament reconstruction.

(6) The Nice knot is a high-tension knot that can slide and self-lock, and can meet the strength required for general fracture fixation. At the same time, under external dynamic stress, the Nice knot can effectively reduce the extension of the knot and resist the tension generated during functional exercise. tension.


3. Operation precautions:

(1) The clavicle bone tunnel must be established in the middle and anterior 1/3 of the clavicle to prevent the clavicle from rotating backwards and the distal end of the clavicle from moving forward during the tightening of the Nice node;

(2) The fixation line needs to pass through the base of the coracoid process. If it passes forward from the body of the coracoid process, the clavicle may move forward or the fixation line may slip from the coracoid process during the tightening of the Nice knot;

(3) During the tightening process of the Nice knot, the acromioclavicular joint should be over-reduced: Although the Nice knot can slide and self-lock, reducing the extension of the knot, the fixation line will creep with postoperative recovery, causing the distal clavicle to recede. bomb.


2. Endobutton Steel Plate with Loop

1. Surgical method:


After the patient is successfully anesthetized via brachial plexus block, he is placed in a supine position with the affected shoulder elevated, routinely disinfected, and draped. An incision is made on the outer clavicle of the affected side, and the skin, subcutaneous tissue, and deep fascia are incised to expose the affected shoulder. Lock joints. During the operation, it was found that the acromioclavicular joint was dislocated, the lateral end of the clavicle was displaced forward and upward, and the acromioclavicular and coracoclavicular ligaments were ruptured. Remove the hematoma, drill holes on the dorsal side 2cm and 4cm away from the distal end of the clavicle, place 2 locking loop steel plates on the dorsal side, and use high-strength wires to bypass the base of the coracoid process to reset the acromioclavicular joint and temporarily fix it with Kirschner wires. When the acromioclavicular joint is reduced satisfactorily, the high-strength thread on the locking loop steel plate is tightened and knotted, the Kirschner wire is removed, the acromioclavicular joint is repaired, the wound is rinsed with normal saline, and sutured layer by layer (Figure 2).



Figure 2 A is the X-ray of the affected shoulder before surgery, B is the X-ray of the affected shoulder after surgery, and C is the postoperative wound.


2. Advantages:

(1) The Endobutton loop steel plate can effectively repair and reconstruct the coracoclavicular ligament, and plays a good role in promoting the functional recovery of the acromioclavicular joint.


(2) The Endobutton steel plate is minimally invasive, the titanium alloy steel plate has good compatibility with human tissue, and there is no need to remove the internal fixation. It can reduce the patient’s pain and allow for faster postoperative recovery.


3. Things to Note:

(1) The selection of the needle entry point in the supraclavicular bone tunnel is very critical. The bone tunnel should be selected about 3.0~3.5cm away from the acromioclavicular joint. The needle insertion point should be located in the middle or slightly behind the cross section of the clavicle. The first drilling should be carefully considered and positioned carefully, and multiple drillings should be avoided. holes thereby causing iatrogenic clavicle fractures.


(2) The location for drilling the coracoid process should be at the base root, where the bone is strong and less likely to cause plate invagination and fracture. During the operation, the periosteal stripper should be used to separate the periosteum closely to the base to completely expose the bottom of the coracoid process. This process should be performed gently to avoid damaging the nerves and vascular bundles in front and below the coracoid process.


(3) Repair the acromioclavicular ligament and joint capsule complex. This repair plays a greater role in the lateral and horizontal stability of the acromioclavicular joint. When starting to reduce the acromioclavicular joint, Kirschner wires should be used to temporarily fix the acromioclavicular joint. After the Kirschner wires are removed, this bone channel can be used, and an Ethibond suture can be passed through it under the guidance of a hard external needle and then knotted to reinforce the acromioclavicular joint.


(4) Shoulder joint CT and three-dimensional reconstruction examinations are routinely performed before surgery. X-ray examination of non-displaced fractures of the coracoid process base is often not reflected. This surgery is contraindicated in patients with coracoid fractures, especially those with fracture lines located at the base of the coracoid process.


(5) Older patients or those with osteoporosis often cause iatrogenic fractures of the clavicle or coracoid process, which is also a relative contraindication to this surgery.



3. Clavicle Hook Plate Fixation


1. Surgical method:

Have the patient undergo surgery in a supine position with the affected shoulder elevated. The skin and subcutaneous tissue are opened from the acromion to the distal clavicle, and the incision length is 5 to 8 cm, effectively exposing the distal clavicle and acromioclavicular joint. Through exploration, the patient’s acromioclavicular joint tear can be found, and Kirschner wires are used to drill holes at the distal end of the clavicle. The pre-prepared 3.0 absorbable sutures are inserted to effectively clean the joint cavity and broken soft tissues, cartilage discs and articular cartilage. According to the specific degree of dislocation and the X-ray film of the healthy side of the acromioclavicular joint, the hook end of the steel plate is pre-bent. The doctor places the hook end tightly against the lower edge of the patient’s acromion and inserts it under the acromion at the rear of the acromioclavicular joint. After completing the above work, place the plate on the upper edge of the distal clavicle. At the same time, a steel plate is used to depress the clavicle to achieve the reduction effect. After that, screws with a diameter of 3.5mm are used to fully fix the plate above the patient’s clavicle. Through reduction inspection, reserved sutures should be used to confirm that the fixation is satisfactory. Effectively repair the acromioclavicular ligament and fix it at the distal position of the clavicle. At the same time, the damaged coracoclavicular ligament and joint capsule are repaired, and then the incision is closed. After the patient completes the operation, the affected limb should be suspended using a triangle towel. Passive activities of the shoulder joint can be carried out after 1 week. If the patient tolerates pain, active activities can be performed. It is worth noting that the abduction should be below 90°. Complete functional exercise was implemented after 1 month.



2. Advantages and Disadvantages:

(1) The advantage of this method is that it causes less damage to the surgical area of the patient, so it does not affect the blood supply around the shoulder joint. Moreover, the cost is relatively low and it is easily accepted by patients.

(2) However, it is worth mentioning that during the treatment of patients using this method, when fixing shoulder joint dislocation, the phenomenon of fixation instability usually occurs, which may cause re-injury of the joint.

(3) When hook plate treatment is used, postoperative shoulder joint pain is the main complication. The reason is considered to be insufficient shaping of the steel plate during the operation, resulting in excessive upward pressure on the acromion from the steel plate hook under the acromion. Some patients have hook plate breakage, which makes it more difficult to remove the plate during the second surgery.





[1] Hong Lejin, Zhang Xiaonong, Sun Zhongliang, et al. Comparative effect of clavicle hook plate and Endobutton loop plate in the treatment of acromioclavicular joint dislocation [J]. Chinese Medical Device Information, 2024, 30(04): 69-71. DOI : 10.15971/j.cnki.cmdi. 2024.04.045.

[2] Wang Lei, Zhang Jie, Wang Fengfeng, et al. Meta-analysis of surgical and non-surgical treatment of type III acromioclavicular joint dislocation [J]. Chinese Journal of Orthopedics, 2024, 32(04): 339-344.

[3] Li Zhenke, Wen Zhiyuan, Li Shihao, et al. Clinical efficacy of Endobutton loop plate internal fixation surgery in the treatment of Rockwood type III acromioclavicular joint dislocation [J]. Chinese Modern Drug Application, 2021, 15(15): 76-79. DOI: 10.14164/j.cnki.cn11-5581/r.2021.15.027.

[4] Lin Min. Comparison of the clinical effects of clavicle hook plate fixation and simple allograft tendon reconstruction of the coracoclavicular ligament in the treatment of acromioclavicular joint dislocation [J]. Chinese and Foreign Medical Research, 2021, 19(04): 21-23. DOI: 10.14033 /j.cnki.cfmr.2021.04.007.


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Post time: Mar-29-2024