Evaluation of Adjustable Loop Fixation in Management of Acute Acromioclavicular Joint Dislocation

Article information Background: Surgical treatment procedures for acromioclavicular [AC] joint dislocation often manifests some complications. Numerous techniques are evaluated, but there is no gold standard method for management of such injuries yet. The Aim of the work: The present study aims at evaluating the results of open single adjustable loop for management of acute AC joint dislocation of types: III, IV and V. Patients and Methods: This study is a prospective cohort work conducted on 20 cases who were subjected to surgical intervention by the adjustable loop fixation system for acute AC joint dislocation. During the follow up phase, Age, sex, dominant hand, injury mechanism, injured side, duration of the monitoring period, shoulder and hand [DASH], time before surgery, pain scores. The average follow-up time was 16.17±4.38 weeks. Results: Patients’ mean age was 34.5±11.5 years, of which four patients [20%] were females, while the rest of them [60%] were males. Pre-operation VAS, post-operation measurements, and constant shoulder scores have all shown very significant differences. On the other hand, the study found no significant differences between right and left coracoclavicular, while two cases of shoulder stiffness were recorded. Conclusion: As per the results, the adjustable loop fixation system used as a treatment procedure for acute acromioclavicular joint dislocation manifested suitable results and had minimal damage to the soft tissues surrounding the coracoclavicular ligaments.


INTRODUCTION
Dislocations of the acromioclavicular [AC] joint represent 9% of shoulder joint injuries. AC joint dislocation typically happens as a result of direct or indirect force [1] . Patients of all age groups can be involved in this type of injury, as it is a common injury caused by accidents related to traffic, sports [as in contact sports such as football players, with an incidence rate of 41%], military training, and falls [2,3] .
The AC joint dislocation is usually graded using Rockwood's classification [grades I to VI], which is based on the severity of damage [4] . Treatment plan for grade I and II AC joint dislocations might be conservative. Although non-operative treatments are advised for type III AC joint dislocations [5] , recent research have revealed that surgical treatments for this kind of damage produce better functional results [6] . Thus, some patients with grade III, those with IV-VI types will require surgical intervention due to the disturbance of AC and coracoclavicular [CC] ligaments, leading to insecurity of the different directions of the joint [7,8] .
Various surgical procedures have been suggested for the treatment of AC joint dislocation. Reducing the gap between the clavicle and coracoid, which results in primary healing of the CC ligament, is the main goal of therapy [9, 10] . However, a gold standard for this damage has not yet been identified. The stabilization of this kind of injury is associated with trauma during surgery, non-anatomical repair, and numerous other consequences as a result of the surgery, as reported by several researches [11][12][13][14] .

THE AIM OF THE WORK
The present work involves the evaluation of reconstructing the regular structure of the AC joint using adjustable loop stabilization technique in acute AC joint dislocation. This work is aims at evaluating the outcomes of open single adjustable loop as a treatment procedure of acute acromioclavicular joint dislocation type III to V.

PATIENTS AND METHODS
Patients subjected to surgical interventions with the adjustable loop stabilization procedure for acute AC joint dislocation were assessed in a prospective study carried out between June 2021 to June 2022, in Al-Azhar University Hospitals, Cairo and Alexandria Armed Forces Hospital, Alexandria. Twenty patients were enrolled into the study: 16 men and 4 women [age range: 22 to 50]. The following three radiographic views were used to determination the type of injury: AP view [with 10 degrees cranial tilt of the beam], stress view of both sides of the AC joint and CC ligament], and true axillary view in the supine position.
Inclusion criteria: Patients with acute AC joint dislocation grades III to V according to Rockwood et al. [4] , who is free from previous shoulder injuries or surgical procedures, and completed follow-up duration of six months. Cases with frozen shoulder or had associated comorbidities were excluded. Cases of type III were included in this study if the radiographs' distal end of the clavicle was visible at a distance ≥ to 75 to 100% of its articular surface width; also, the presence of painful palpation and clavicle protuberance during shoulder anterior elevation during clinical diagnosis. A senior surgeon handled every intervention, and the same adjustable loop approach was used in every case. Before surgery, age, sex, mechanism of injury, dominant hand, side of damage, and time before surgery were all noted.

Surgical technique:
Once the patient is positioned in the deckchair posture, the integrity of the shoulder and AC joint reductions was assessed. Every test was carried out while under either local or general anesthesia. Before skin incision, all patients received doses of thirdgeneration cephalosporin to prevent infection. The subject's wounded upper limb was initially prepped and draped in sterile conditions. The skin incision for this procedure was determined using anatomical markers like the coracoid process, distal clavicle, and the front region of the acromion. Following palpation of the coracoid process tip, a 4-6 cm long skin incision was performed. From the upper border of the trapezius down to the coracoids, a 2-3 cm medial incision was made to the AC joint. The incision line was then widened.
The gap in between coracoid process and the terminal section of the clavicle was separated at that point. A curving soft tissue lifter was used to medially and laterally slice the tissue. The AC joint was exposed by continuing the side flaps. Initially, two drill holes using 2.4 mm guide pin done, one on the clavicle [midway between anatomical attachments of CCL] 2.5-3 cm medial to AC joint and another drill hole on the bottom of coracoid. Then, the guide pin was carefully over-drilled by a 4.5 mm drill. Then, the guide pin and drill were removed. At first, a button inserter was used to place the flexible loop through the coracoid hole and into the clavicle hole. The first button was then turned over and secured beneath the coracoid process by pulling a traction suture. This procedure involved applying pressure while employing fluoroscopic visualization to reduce the AC joint in the natural position. The second button was then positioned and attached on the upper side of the clavicle in this location, and while a helper held the reduction, the button was then fastened with approximately five knots. Shoulder mobilization was examined in accordance with post-operative guidelines.

Follow up:
The final follow-up when the patient completing 6 months after operation. Visual analogue scale [VAS], constant [15] , and shoulder and hand [DASH] scores [16] were recorded prior to and following surgery, and were used for functional assessments during the follow-up period. Additionally, on the standard view of the anteroposterior radiographs taken on both sides in the most recent follow-up, the vertical distance between the superior border of the coracoid process and the anterior-inferior border of the clavicle was measured. All complications were recorded.
Statistical analysis: Information was entered into the SPSS-16 program. Frequency, percentage, mean, and standard deviation [SD] were employed for qualitative data. The t-test was applied to compare the quantitative data from before and after surgery. The significance level was set at a P-value of 0.05. In Table [ All complications were recorded postoperatively and we found that 12 cases (60%), had no complications, 4 cases (20%) had Pin tract infection, two cases (10%) had shoulder stiffness, one case (5%) had wound infection and one case (5%) had wound sinus. There was no intraoperative complication [ Table 3].

DISCUSSION
There have been several suggestions for treating acute AC joint dislocation. For the management of full AC joint detachment, more than 70 strategies have already been recommended [17] .
The evidence does indicate that these procedures have a significant rate of difficulties. To handle AC joint dislocation, other methods like Kirschner wiring, needles, pins, or hooked plates are again employed [18][19][20][21] .
The most important objective of all approaches is to restore the AC joint's physiological functions by minimizing dislocation, stabilizing the distal part of the clavicle, and creating a situation for tissue rebuilding. However, incompetency has been demonstrated for these techniques, when the pin or cerclage are used as a temporary fixation due to the pin or cerclage's high incidence of degenerative changes, breaking of the pins, equipment mobility into the thoracic cavity, and bony lesions; so, these techniques have not been recommended for long-standing management . The joint capsule and AC ligament provide a horizontal restriction while the CC ligament plays a significant role in exerting force against vertical translation. Previous studies on the biomechanics of the CC ligament complex have revealed that this complex has a special function in the anterior and superior displacement of the clavicle [22,23] .
Sutures have been utilized in some procedures to shorten the time between AC joint dislocations. Sutures, however, can have sawing effects and cause these procedures to fail [24,25] . Ponce et al. [26] employed tendon auto graft for augmentation fixation in revision instances and nine No. 1 absorbable sutures enfolded in a tension cable rope pattern for AC joint reconstruction.
In this study, we included 20 patients with acute dislocation the AC joint type III, IV and V. Surgical management by the adjustable loop technique was conducted, where we used 2 buttons with suturing on the upper and lower parts. Consequently, the burden applied on the AC joint was distributed similarly; thus, avoiding the slicing forces of the sutures.
As per the studied scores, the used maneuver had satisfactory outcomes in cases of acute AC joint dislocation. In comparison to pre-operation data, post-operative Dash and VAS scores were lower, whereas constant shoulder ratings were greater. This demonstrated that patients were convenient with this method. Two incidences of shoulder stiffness were noted during the followup.
In a related study, Beris et al. [27] treated acute acromioclavicular joint dislocation with a double-button fixation device. They examined 12 individuals, using the DASH, Constant, and VAS scores as well as the CC distance. There were no reports of osteoarthrosis of the AC joint, CC calcification, osteolysis of the distal clavicle, or coracoid process. The mean DASH score dropped at the most recent follow-up, while the mean constant score increased compared to the mean pre-operative value of 34.4. The average VAS score dropped, and the average CC distance from the operated shoulder was comparable to the CC distance from the unoperated side. Their findings support the findings of the current study.
In 18 patients with acute AC joint dislocation, Shin et al. [28] investigated the postoperative consequences from arthroscopic CC reconstruction employing a single adjustableloop length suspensory fixation device. Their findings demonstrated positive clinical outcomes following surgery. Within three months of surgery, radiographic scans revealed CC fixation failure of greater than 50% of the unaffected side for 33% of the patients. Eight patients [44%] reported surgical technical issues and complications related to the adjustableloop-length suspensory fixation device.
Good clinical outcomes have been documented in numerous other investigations using these single metallic suspension devices attached at the isometric point of the CC ligament [1] ; nevertheless, the potential of subsequent subluxation remains a concern [28] . Hardware displacement into the clavicle, coracoid, or both was the most often mentioned problem. According to Scheibel et al. [29] , the rate of migration reached 89%. Additionally, many patients report ongoing postoperative discomfort from hardware irritation at the superior clavicle fixation site [30] .
Limitations: the main limitation of the study is the small sample size; in addition, the majority of patients had grade III AC dislocation, which restrict the generalization of these results regarding type VI and V. Finally, the duration of follow-up in this study is relatively short; thus, some complications may be appeared later.

Conclusion:
The present study's findings indicate that the adjustable loop fixation device is an effective method for treating acute acromioclavicular joint dislocation and causes little harm to the soft tissues surrounding the CC ligaments.

Conflict of interests:
None.