Is it inevitable to have dynamic horizontal acromioclavicular joint instability with a single Tightrope? A randomized prospective study

Abstract Purpose: We hypothesized that not all cases of single Tightrope fixation in acromioclavicular joint dislocation cases should give positive clinical cross body adduction test and might have some certain degree of horizontal stability which might be confirmed with ultrasound examination. Materials and Methods: This clinical study was performed on twenty-seven patients who retrospectively underwent single Tightrope application in acute acromioclavicular joint dislocation. Patients were divided into group A which had an arthroscopic technique and group B that had an open technique augmented with trans-acromioclavicular joint fixation using two k-wires for six weeks in all group B cases. Clinical examination of operated shoulders was done, and results were compared to sound shoulder examination in the same patient at the last 24 months post-operative follow-up visit besides, results of the cross-body adduction test were correlated with ultrasound findings at the same visit. Records, operative details, and post-operative X-rays were reviewed to assess if any factors would diminish the dynamic horizontal stability of the acromioclavicular joint. Body mass index (BMI(was calculated per each case. Results: Group A had seventeen cases, three had grade III and fourteen had grade V dislocations. Group B had ten cases, four had grade III, and six had grade V. Clinical cross-body adduction test gave gross positive results in fourteen patients in group A and six patients in group B. Group A patients with negative results were three while Group B patients with negative results were four. For ultrasound findings, differences in horizontal translation of the clavicle within the acromioclavicular joint in resting and cross-arm positions were more obvious in all operated shoulders than all sound shoulders. Conclusion: The less the Rockwood grading, the more potential to secure more horizontal stability. An open approach also gives more horizontal stability. With increased BMI, horizontal instability is usually masked. So, some factors may diminish, or mask clinical dynamic horizontal instability which can be confirmed or rolled out with ultrasound usage.