Summary

Clinical outcomes from acute and chronic ACJ reconstruction with LARS ligament using a 3-tunnel technique

Abstract

Introduction

Acromioclavicular joint dislocations are commonly occurring injury accounting for 9-12% of the shoulder injuries. It is generally agreed that Rockwood type I and II are managed conservatively and surgical management is reserved for patients with higher grades of injury; type III to VI. More than 150 surgical techniques have been described in literature with biomechanical and anatomic studies to support efficacy and variable clinical outcomes1; but there is still no consensus regarding the most appropriate technique for management of higher grades of injury.
In this research, we will be describing our 3-tunnel technique of surgical management of both acute and chronic ACJ dislocations with clinical outcomes.

Material And Methods

This study includes 21 consecutive patients, from July 2016 to Jan 2021, with ACJ dislocation who underwent superior shoulder suspensory ligament complex reconstruction using LARS. Only subjects who had ACJ dislocation of Grade III to Grade VI, according to Rockwood classification, were included irrespective of their age and duration of injury. All the cases were operated by the same surgeon.
Patients were followed up at 3 months, 6 months and one year for clinic-radiological outcome. Local institutional board ethics approval was attained and appropriate consent was obtained. All patients were evaluated clinically using a Constant Score, ASES, VAS, SST at sequential follow-up.

Results

& Discussion
The mean age of the study group was 48 years (range 16 – 76 years). Right shoulder was affected in 11 patients while left shoulder in remaining 9 patients. All patients reported trauma as the causative factor. 9 patients had Rockwood type 5 injury; 2 patients had Rockwood type 4 injury and 9 patients had Rockwood type 3 injury with anteroposterior instability. One patient did not complete the follow up at one year and was excluded.
Mean duration of dislocation was 19 months (range 2 days – 15 years). At a minimum follow up of 12 months, no tunnel widening or acromial fracture was noted radiologically and the CC distance was maintained in all cases. All patients returned to full active lifestyle, work and sports. Improved patient outcomes were reported for VAS (from 4 to 1), Constant (from 43 to 74), SACS (from 62 to 10), ASES (from 49 to 84), and SST (from 16 to 78), respectively. The range of motion improved in forward flexion from 130? to 166?; lateral elevation from 118? to 155?; and ER1 from 54? to 65?. No re-rupture or loss of reduction was noted. One case required removal of LARS at one year due to infection.
Several synthetic ligaments have been used for the purpose of ACJ reconstruction however, complications such as ligament failure, incomplete reduction, foreign body reaction, bony erosion, coracoid fractures, and clavicle fractures have been reported with these implants. In comparison to our results, the failure rate and loss of reduction was reported higher in many of these studies. The possible reason would be the use of screws for fixation in clavicular tunnels and the technique utilized to only reconstruct the CC ligament which would only provide vertical instability.
In our technique we use three tunnels; two in clavicle and one in acromion to reconstruct both AC an CC ligaments. This provides both horizontal and vertical stability by complete restoration of superior shoulder suspensory ligament complex. No screws are used for fixation of the LARS in tunnels which prevents the tunnel widening, bone erosion and screw related complications. To date, a single study has been published for fixation of both acute and chronic ACJ dislocations which reported one ruptured LARS ligament and one case of deep wound infection requiring revision surgery, and implant removal (screw) was performed in one patient2. Their technique only reconstructed CC ligament. We did not find any re-ruptures and complications related to screws were avoided due to a modified fixation technique.