Arthroscopically Assisted Stabilization of Chronic Acromioclavicular Joint Instability
Authors: Bellmann Frederik , Dittrich Michael , Wirth Barbara , Freislederer Florian , Scheibel Markus 
Published: November 2021

Background:
This video article demonstrates biological and synthetic acromioclavicular (AC) and coracoclavicular stabilization with use of a hamstring tendon graft and a low-profile TightRope implant (Arthrex). The low-profile TightRope reduces soft-tissue irritation due to knot stacks
1
. The tendon graft is wrapped around the clavicle and the coracoid to avoid weakening of the osseous structures as a result of clavicular and coracoidal tunnel placement
2
.

Description:
For this procedure, the patient is placed in the beach chair position. After establishing standard posterior, anteroinferior, and anterolateral (transtendinous) portals, the arthroscopic preparation of the coracoid base is performed. Next, transcoracoidal-transclavicular drilling is performed, and a nitinol suture passing wire is utilized to aid the placement of the TightRope later in the procedure. The graft passage around the clavicle and the coracoid is then set up by placing 2 additional nitinol suture passing wires. Following this, coracoclavicular stabilization is performed with use of the low-profile TightRope device, after which the graft is shuttled around the clavicle and the coracoid with the help of the passing wires. After the acromial drilling, the graft is shuttled laterally transacromially and subcutaneously back to the clavicle, completing the AC cerclage. Finally, the graft ends are sewn together under tension. The deltotrapezial fascia is closed above the graft, incorporating the tendon ends into the suture. Finally, the skin can be closed.

Alternatives:
In case of chronic AC joint injuries, many surgical stabilization techniques have been described. On the one hand there are rigid stabilization techniques like the hook-plate or temporary Kirschner wire fixation. On the other hand, there are dynamic stabilization techniques like the modified Weaver-Dunn procedure or solitary synthetic coracoclavicular reconstruction with use of pulley-like devices, with or without additional AC stabilization
3
. As for nonsurgical alternatives, physiotherapy with periscapular stabilization and muscle strengthening may be an option
4
.

Rationale:
For the treatment of chronic AC joint instability, many techniques
5–9
have been described that utilized horizontal and vertical stabilization with a tendon graft combined with a synthetic pulley-like device. Usually, multiple transclavicular and transcoracoidal drill holes are utilized for the graft passage, which could weaken the bone and may result in postoperative fractures of the coracoid and clavicle
10
. Considering this, we present a modified technique that focuses on the optimization of the graft passage. In contrast to other aforementioned techniques, this procedure requires only 1 transcoracoidal-transclavicular tunnel for the TightRope and another transacromial tunnel for the passage of the AC cerclage. By forming a loop of the graft around the coracoid and the clavicle, the graft passage is managed without any additional coracoidal or clavicular drilling.

Expected Outcomes:
A dedicated study investigating the specific clinical and radiographic results of our technique will be part of future research. Because the biomechanical principle of reconstruction of our technique is very similar to the technique described by Kraus et al., we refer to their clinical and radiographic results regarding the expected outcome. As shown in the chart in the video, Kraus et al. demonstrated good clinical and radiographic results with their biologic and synthetic AC-stabilization technique at a median follow-up of 24 months. The outcomes measured in that study were the Constant score, Subjective Shoulder Value, AC Joint Instability Score, and Taft score. Patients were divided into 2 groups. Group 1 included patients with failed prior conservative treatment, and group 2 included those with failed prior surgical treatment. Overall, the authors report complete dynamic posterior translation in 1 patient and partial dynamic posterior translation in 5 patients. Although there was no notable enlargement of the TightRope drill hole, the authors of that study found a significant enlargement of the clavicular graft tunnels. However, the enlargement had no clinical relevance
10
.

Important Tips:

Utilize a low-profile TightRope device to minimize the risk of suture irritation from knot stacks.The tendon graft should be ≥24 cm in length. If the graft is too short, perform an end-to-end anastomosis of 2 grafts.Utilize an image intensifier to ensure correct drill hole placement and avoid damage to neurovascular structures.The graft passage around the clavicle and the coracoid can be dilated by hand with the use of differently sized drill bits.Incorporate the graft into fascial closure at the end of the procedure.