The study protocol and consent form were approved by the hospital institutional review board. All patients provided written informed consent before participating in the study.
The study was conducted at the Changshu Hospital Affiliated to Nanjing University of Chinese Medicine, Jiangsu, China. Criteria for surgery were (1) Rockwood type III to V AC joint dislocation, (2) other concomitant injuries in the ipsilateral upper limb, such as fractures or rotator cuff tears, were excluded, (3) patients aged 18-70 years, (4) the duration between joint injury and surgical treatment less than 2 weeks. Consequently, we retrospectively reviewed the medical records of 60 patients of AC joint dislocation between April 2014 and June 2016. 8 patients did not fulfill the criteria and 4 patients were lost to follow-up between 6 and 12 months, the final clinical trial involved 48 patients (34 men and 14 women, 26 left and 22 right) with AC dislocations by TACCR and TAACR method for the treatment of high-grade AC joint dislocation. (Table I). The diagnoses were confirmed with preoperative radiographs (anteroposterior and axillary views). All operations were performed by the same experienced surgeons.
Anchor moored positioning technique
The operative techniques were shown in Fig. 1–A through 1–D. The operation was performed under brachial plexus anesthesia with the patient in the beach-chair position. A transverse incision of approximately 5 cm in length was made at the distal clavicle to expose the AC joint (Fig. 2-A). And then the cartilage disc was removed. A vertical incision of approximately 3 cm in length was made from the lowest border of the clavicle to the coracoid process (Fig. 2-A). Then a tunnel was drilled with a 4.5-mm drill-bit from superior to inferior through both cortices of coracoid process. The inferior hole of the coracoid tunnel should be at central portion of the coracoid base. The first Ethibond suture was passed through the medial 2 holes of the Endobutton (12mm*4mm, Smith & Nephew Inc., Andover, MA, USA) and the second Ethibond suture was passed through another 2 holes (Fig. 2-B). Both Ethibond sutures were attached with traction sutures. With the help of the traction suture, the Endobutton was passed through the coracoid tunnel and was fixed at the horizontal position close to the coracoid base. A 2.0 mm Kirschner wire was temporary inserted from acromion to the distal clavicle to maintain anatomic reduction of the AC joint. Then a same clavicular tunnel was drilled with a 4.5-mm drill-bit at the lateral 1/5 position of the clavicle. The 2 Ethibond sutures were then pulled through the clavicular tunnel with the use of traction sutures and were tied on the second Endobutton. A 3.5 mm suture anchor (TwinFix Ti 3.5mm, Smith & Nephew Inc., Andover, MA, USA) was inserted approximately 1.0 cm near the coracoid tunnel into the base of the coracoid. A 1.5 mm tunnel was drilled approximately 1.5cm near the clavicular tunnel on the distal clavicle to pass the suture of TwinFix anchor and tied on the clavicle to reconstruct the trapezoid ligament. The surgeons then removed the 2.0 mm Kirschner wire and inserted another 3.5 mm TwinFix suture anchor vertically into the acromion. Another new 1.5 mm tunnel was sagittally drilled on the distal clavicle to pass the suture of TwinFix anchor and tied on the clavicle to reconstruct the AC ligaments. The ruputured AC and CC liagaments were repaired with absorbable sutures. The surgeons then checked the stabilization of the AC joint by testing passive shoulder motion and used a mobile C-arm to confirm the restoration.
The injured arm was kept stable with a triangular sling for 1–2 weeks after the operation. Active hand and elbow movements were encouraged immediately after surgery, and passive exercises including abduction, lifting and circling of the shoulder were initiated 3 days after the operation. The patients were allowed to perform active progressively range of motion exercises of the shoulder after 4 weeks postoperatively. Progressive resistance exercises and weight training exercises were encouraged after 2 months postoperatively. After 6 months, the patients are allowed to back to normal activities.
Functional outcome and radiographic measures
The clinical and radiologic follow-up was at 1, 3, 6, 12 and 24 months after the operation. The visual analog scale (VAS), Constant scores  and American Shoulder and Elbow Surgeons (ASES) scores  were used as the clinical assessments for shoulder function. Radiographs were performed 2 days after surgery and at each follow-up. Anteroposterior radiographs for the bilateral AC joints and axillary radiographs for the injured side were collected. All radiographic measurements were made using the Picture Archiving and Communications System (GE Healthcare, Chicago, IL, USA). We measured the coracoclavicular (CC) vertical distance (CCD) on the preoperative and postoperative x-rays. The CCD was the vertical distance between the top-most border of coracoid and the lowest border of the clavicle. We compared the CCD of the injured and uninjured sides and defined CCD ratio as (CCDin-CCDun) /CCDun*100%. We also measured the clavicular length (CL), which was the length from the medial border of the clavicle to the lateral border, the distance from the lateral border of the clavicle to the center of clavicle bone tunnel (CTD) and defined the clavicular tunnel ratio (CTR) as CTD/CL*100%. The angle between the two midlines of the clavicle bone tunnel and the coracoid bone tunnel (CCα) were also mesdured on the anteroposterior x-ray (Fig. 3).
The measurement data were presented as the means ± standard deviation. The CCD, CCD ratio and CL were compared with unpaired Student t test. The functional scores and radiographic differences between preoperative and postoperative results were compared with the paired Student t test and Wilcoxon signed rank test. Statistical analyses were performed using SPSS 22.0 software (IBM, Armonk, NY, USA). P < .05 was considered statistically significant.