The Infinity-Lock System for Chronic Grade III AC Joint Dislocation: A Novel Technique, Rehabilitation Protocol and Short Term Results

Background: the choice of treatment of chronic grade III acromioclavicular (AC) joint dislocation is controversial. Several surgical techniques have been described in the literature, responding differently to nonoperative treatment. The aim of this study is to describe a modified technique of stabilizing an AC joint dislocation with the new Infinity-Lock Button System, in order to demonstrate that it is effective in optimizing outcomes and decreasing complications. Methods: this is a retrospective study of 15 patients who underwent surgical stabilization of the AC joint dislocation between 2018 and 2019, through modified surgical technique using the Infinity-Lock Button System. Active range of motion (ROM), Specific Acromio Clavicular Score (SACS) and Constant Score (CS) were evaluated preoperatively and postoperatively at last 18 months follow up. Patients rated their outcomes as very good, good, satisfactory, or unsatisfactory. Results: a total of twelve patients rated their outcome as very good and three as good; no patients were dissatisfied with surgery. The mean Constant Score increased from 38 points preoperatively to 95 postoperatively, the average SACS score decreased from 52 points preoperatively to 10 postoperatively, both significantly. No complications were detected. Conclusion: the described technique is effective for treatment of chronic grade III AC joint dislocation, resulting in elevated satisfaction ratings and predictable outcomes. Nevertheless, further longer term follow-up studies are required.