Influential factors of subacromial impingement syndrome after hook plate fixation for acromioclavicular joint dislocation

Abstract Subacromial impingement syndrome (SIS) after hook plate fixation for acromioclavicular joint (AC) dislocation was the most common complication. However, the researches on its’ influential factors were rare. The purpose of this study was to identify the risk factors by analyzing the influencing factors of postoperative SIS and minimize the incidence of SIS in clinical surgery. We retrospectively analyzed the prospectively collected data from 330 consecutive patients with AC joint dislocation between August 2014 and August 2017 at our institute. The SIS was presented as the dependent variable at the last follow-up when the internal fixation was removed. The independent variables included age, gender, body-mass index (BMI), smoking status, alcohol consumption, type of injury, Rockwood Classification, site of injury, operation time, injury-to-surgery, the distance between the hook body and the acromion (DBA), the depth of hook tip (DHT), the distance between the hook plate and the humeral head (DHH), the distance between the acromion and the humeral head (DAH), the hook plate angle (AHP) and acromial shape. Logistic regression analysis was performed to identify independent influential factors of SIS. A total of 312 cases were included and 18 cases were lost. The follow-up rate was 94.5%. In without SIS group, there were 225 cases (123 males and 102 females). In with SIS group, a total of 87 cases were included (56 males and 31 females). The incidence of SIS was 27.8%. DHT (OR = 9.385, 95% CI = 4.883 to 18.040, P < .001) and DBA (OR = 2.444, 95% CI = 1.591 to 3.755, P < .001) were the significant independent risk factor for SIS of AC dislocation treat with hook plate. DAH (OR = 0.597, 95% CI = 0.396 to 0.900, P = .014) and acromial shape with flat and straight (OR = 0.325, 95% CI = 0.135 to 0.785, P = .012) were also independent factors of SIS, but they were all protective. The SIS had a high incidence in fixation of clavicular hook plate for AC dislocation. DHT and DBA were two independent risk factors, DAH and acromial shape with flat and straight were two independent protective factors for SIS. In clinical surgery, we should avoid risk factors to reduce the incidence of SIS.