1 Introduction

Acromioclavicular (AC) joint dislocation is a common traumatic shoulder insult with male to female ratio (5:1).^1,2 Direct strike to the lateral aspect of the shoulder is the most common mechanism of this injury.³

Rockwood⁴ classified the (AC) joint disruption into six types according to the direction and the severity. Conservative treatment is indicated in types I and II.^5–7

Surgical treatment is recommended for types IV, V and VI and young active patients with type III.^8–10

Most of the present studies advocated early surgery for acute type ΙΙΙ injuries in highly demanded patients because it had significant better functional results compared to conservative treatment.¹¹

There are several methods used for fixation like K-wires, hook plate, Bosworth screw, Weaver-Dunn and resection of the lateral end of the clavicle, with no gold standard procedure.^10,12–16

Wound healing problems, the need for second operation to remove the hardware, big scar and infection are common problems associated with the traditional open techniques.¹⁷

An arthroscopic technique using the TightRope device for fixation of acute (AC) joint dislocation is minimally invasive procedure with lower morbidity compared to open techniques has been recently developed.¹⁸

The aim of this study was to evaluate the short term results of arthroscopic assisted fixation of acute high grade (AC) joint disruptions using TightRope device in young active patients.

2 Material and methods

This prospective study was done on twenty four young active patients with acute high grade acromioclavicular joint dislocation (<3 weeks) at Zagazig University Hospitals between February 2013 and February 2017. All patients were treated with arthroscopic assisted fixation using TightRope system. This study was approved from our university IRB ethical committee and informed consents were taken from all patients.

Chronic dislocation (>3 weeks), Rockwood type I and II dislocation, (AC) joint arthritis, type III dislocation in elderly (>60 years) inactive patients with sedentary life and patients associated with other intra-articular lesions were excluded from this study.

The demographic criteria of the studied groups were presented in (Table 1).

2.1

2.1 Surgical technique

Pre-operative anti-biotic was given for all cases. The operation can be done under general or regional anesthesia (inter scalene block). The patient was positioned in beach chair position. Three arthroscopic portals were used in this technique (Fig. 1A). Diagnostic arthroscopy of the shoulder was done through the standard posterior portal to detect other gleno humeral joint lesions e.g SLAP lesion and rotator cuff tear. The antero-superior and antero-inferior portals were done using spinal needle from outside in. The rotator interval was completely released exposing coracoid process. The arthroscope was switched to the antero-superior portal for better viewing the base of coracoid process.

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Fig. 1 (A) Pre-operative picture of the left shoulder showing skin landmarks and portals. (B) Intra-operative image showing the cannulated drill came out of the under surface of the coracoid. (C) The button of the TightRope flipped on the inferior surface of the coracoid process.

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The under surface of the coracoid process was exposed using electro cautery device from the antero-inferior portal. Closed reduction and temporary 1.2 mm K-wire fixation under image intensifier from the lateral border of the acromion was done.

The tip of AC TightRope drill guide was centered under base of coracoid process through antero-inferior portal. The top of the drill guide was positioned over the superior surface of the lateral end of the clavicle where 1.5 cm skin incision was done down to bone. The top of the guide system was positioned at the center of the superior surface of the clavicle. A 2.4 mm guide pin was drilled from the clavicle to the base of coracoid under direct vision until the tip of the pin exited the inferior cortex of the coracoid.

A 4 mm cannulated drill was passed over guide pin under direct vision until it came out of the inferior surface of the coracoid (Fig. 1B).

The guide pin was removed leaving the drill in place, the nitinol wire was passed through the cannulated drill and taken out through the antero-inferior portal by a grasper leaving the suture loop superiorly and the drill was removed. The traction suture of the TightRope was passed through suture loop; traction was done until the button was flipped under the inferior surface of the coracoid (Fig. 1C). The TightRope was tightened, the K-wires were removed from the lateral border of the acromion and final tightening and tying of the TightRope suture was done under image intensifier to check the reduction. The wounds were closed in layers.

2.4

2.4 Radiological follow up

Postoperative X-ray was taken at 0, 6 weeks, 3 months, 12 months and 24 months (Fig. 2). The coraco-clavicular distance before and after surgery was measured.

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Fig. 2 (A) Pre-operative radiograph of the left shoulder shows Rockwood type V dislocation. Post-operative x-rays after reduction and fixation with TightRope were taken at 0 (B) and at 6 months (C).

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3 Results

The mean follow up time was 23.25 ± 7.1 (12–35) months. No patient was missed during the follow-up period. The main causes of injury were motor cycle 9 cases (37.5%), motor vehicle 6 cases (25%) and pedestrian injuries 5 cases (20.8%). The most common type of injury was type V 19 cases (79.2%).

The mean time of return to work was 10.21 ± 3.6 (7–14 weeks) while, the mean time interval from injury to surgery was 7.5 ± 4.04 (3–19 days).

There was statistically significant improvement in the means of Constant score, (UCLA) scale and (cc) distance from 32.75 ± 7.4, 8.5 ± 2.1 and 21.7 ± 3.05 mm to 93.2 ± 2.7, 33.2 ± 2.3 and 10.2 ± 2.4 mm at the end of follow up respectively. P- Values < 0.00001 (Table 2).

There were no intraoperative complications such as fracture clavicle or fracture of the coracoid process. All cases regained their normal range of motion. No wound complications or infections were encountered. There was no need to remove the implant in any patient.

Only two complications were encountered, one patient had over correction of the (AC) joint due to over tightening of the TightRope sutures, but this patient had satisfactory functional results without any complaint at the end of the follow up (Fig. 3) and the other had post-operative mild burning pain along the course of ulnar nerve. The pain was completely resolved 6 weeks post-operative without neurological deficit.

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Fig. 3 Post-operative x-ray shows over reduction of the (AC) joint.

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4 Discussion

Surgical treatment of acute (AC) joint disruption is still controversial among the orthopedic surgeons.¹⁹ Various methods of fixation were utilized such as K-wires, hook plate and coraco-clavicular screws.

Many drawbacks were encountered with these techniques like K-wire migration and breakage. The increased risk of infection, shoulder stiffness, big scar and the need of second procedure for implant extraction associated with open hook plate. Also coraco-clavicular screw failure and subluxation after its removal.^20–22

The recently developed arthroscopic fixation of (AC) joint dislocation using TightRope device had the following advantages: minimal risk of stiffness, less infection, detection of associated shoulder lesions, short hospital stay, less wound healing problems and no additional surgery is required to remove the implant.²³

The rationale of this procedure is to maintain the joint reduced during the initial phase of healing (<3 weeks) to permit healing of coraco-clavicular ligament, acromioclavicular capsule and the deltotrapezial fascia.²⁴

Gstettner et al.¹¹ favored early operative intervention for grade III dislocation in young active patients to avoid persistent pain and improve shoulder function. So, we included these patients in our study accordingly.

The patients in our study were operated using single TightRope device to avoid the risk of coracoid fracture. In a biomechanical study by Beitzel et al.,²⁵ there was no difference in the stability between single and double device but the incidence of coracoid fractures was much higher with double device.

A previous study was conducted on ten patients with acute (AC) joint dislocation fixed arthroscopically by TightRope, the mean postoperative Constant score was 96.3 and all patients had satisfactory clinical and radiological results except in one case due to technical intraoperative error.²⁶

Seventeen patients with acute (AC) joint disruption were operated by Chaudhary et al.²⁷ using TightRope device. The mean postoperative Constant score was 86.4, the mean time to return to work was 4 months and the (CC) distance decreased from 21.5 mm preoperatively to 9.8 mm postoperatively with only one case failure.

Gupta et al.²⁸ performed a study on ten patients with acute (AC) joint dislocation. The mean postoperative Constant score was 92.2 and satisfactory reduction was achieved in all cases.

Referring to our study, the mean postoperative Constant score was 93.2 ± 2.7, the mean post-operative (UCLA) scale was 33.2 ± 2.3 and the post-operative (cc) distance was 10.2 ± 2.4 mm with high statistically significant difference between the pre-operative and post-operative means of these scores (p-value<0.00001). All patients had satisfactory functional and radiological results. They regained their normal range of motion in comparison to the healthy side and returned to the previous activity level at the end of follow up. The results of our study were comparable to the aforementioned studies.

There were no cases of infection or failure. There were only two complications, one case had over reduction of the (AC) joint due to over tightening of the TightRope sutures with no functional deficit and the other had mild post-operative burning pain along the course of ulnar nerve. The patient was given neurotonics and the pain was completely resolved within 6 weeks post-operative without neurological deficit.

A study by Jensen et al.,²³ open hook plate was used in 30 patients. The reported complications were hypertrophic scar (63%), revision surgery (13%) and one case of fracture acromion. The complications in our study were fewer and minor compared to the previous study.

The limitations in our study were as follow: it was done on small number of patients. It was a short term study that needs long term follow up to detect (AC) joint arthritis and subluxations. The scores used for functional evaluation were not specific for (AC) joint injuries. There was no control group to compare this technique with other methods of fixation. Finally, this procedure is technically demanding which needs an experienced surgeon in shoulder arthroscopy.

5 Conclusion

Our study demonstrated that arthroscopic assisted fixation of acute high degree (AC) joint disruption in high demand patients using TightRope is safe, minimally invasive procedure with good to excellent short term functional outcomes and low morbidities but it is technically demanding and should be done by surgeons well trained in shoulder arthroscopy.

Conflicts of interest

The authors declared that there is no conflict of interest related to this study.