Subacromial Erosion After Hook Plate Fixation in Acute Acromioclavicular Joint Dislocation.

OBJECTIVES

To determine the incidence of subacromial erosion, perform quantitative analysis, and identify risk factors after locking hook plate fixation for acute acromioclavicular joint injury.

DESIGN

A retrospective case series study.

SETTING

A single tertiary university hospital.

PATIENTS/

PARTICIPANTS

The study was conducted on 35 patients who had acute acromioclavicular joint injury.

INTERVENTION: Patients underwent the locking hook plate fixation.

MAIN OUTCOME MEASUREMENTS: The computed tomography (CT) was conducted to measure the subacromial erosion. The acromioclavicular slope (AC slope) of the unaffected side, the acromion-hook angle, the acromioclavicular anteroposterior distance (AC-AP distance), and the preoperative acromioclavicular interval of the affected side were analyzed to identify the risk factors of subacromial erosion.

RESULTS

According to the CT findings, subacromial erosion was found in all cases, and the mean value was 5.0 mm, which is 53% of the entire acromion thickness. The AC slope (B = -0.159, P < 0.001) and AC-AP distance (B = 0.233, P = 0.004) were found to have a significant influence on postoperative subacromial erosion. The AC slope showed a negative correlation with the amount of erosion, whereas the AC-AP distance showed a positive correlation with erosion.

CONCLUSION

The CT findings revealed that subacromial erosion occurred in all cases, and the mean erosion depth was about 50% of the acromial thickness. If the preoperative AC slope of the unaffected side was more acute and the AC-AP distance was larger, the incidence of subacromial erosion was higher.

LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.