Evaluation of the necessity of arthroscopic acromioplasty in patients with isolated subacromial impingement by the degree of coracoacromial ligament degeneration and acromion type

Introduction: Subacromial impingement syndrome(SIS) is the most common cause of shoulder pain in patients. Typically pain occurs in this syndrome as; the bursae between coracoacromial arc and humeral head, rotator cuff tendons and long head of biceps tendon impinges when the patient raises their arm. The first line of treatment for SIS is conservative approach as surgery is considered in patients when the former has failed to treat the symptoms. It has been reported before that coracoacromial ligament (CAL) degeneration can occur at variable degrees and that it is diagnostic for SIS. Also it has been shown that patients with hooked or curved acromion morphology are more prone to SIS. Recently the necessity of arthroscopic acromioplasty in SIS has been debated and considered not superior to conservative management by some authors. In this study, we included patients without SIS and only frozen shoulder pathology as the control group; then evaluated the effect of the degree of CAL degeneration and the acromion morphological type on long-term functional results in patients who underwent arthroscopic acromioplasty for isolated SIS. This study aims to show that arthroscopic acromioplasty is beneficial in patients with isolated SIS and advanced CAL degeneration; and whether the acromion morphologic type can be used as a preoperative indicator for the requirement of acromioplasty procedure. Material & Method: Patients that applied to Gazi University Faculty of Medicine's Orthopedics and Traumatology department with isolated SIS and failed conservative treatment and therefore received arthroscopic acromioplasty between December 2012 and 2018 are included in this trial as study group(n=125). Patients who had isolated frozen shoulder and received arthroscopic rotator interval excision were enlisted as the control group(n=40). Patients that had other shoulder pathologies were discarded from the study(n=496). Patients that had at least two-year follow-up were included in the study. All patients were operated by the same surgeon with the same method and the patients underwent the same postoperative rehabilitation program while the shoulder scores were measured by one clinically experienced physician. All subject's preoperative X-rays, MRI scans, UCLA and VAS scores were collected prospectively. Patient's acromion morphologic type was determined and noted using these. CAL degeneration levels were determined from video archives of the cases using Copeland-Levy classification. All patients were evaluated again after minimum two years from the surgery using UCLA, VAS and modified Constant-Murley shoulder scores. Findings: Mean age of the study and control groups was 50,33±8,02 and 51,40±8,86 respectively. There were no statistical differences amongst groups by gender or age. Mean follow up was 36,70±11,93 (months) for all patients. When patients in the trial group were compared for their CAL degeneration levels using postoperative functional and patient reported outcome measures, there were no statistically significant difference between the minor fraying(n=59) and major fraying(n=66) group(p>0,05). When the patients were compared for their acromion types, there weren't any significant differences in the outcome measures amongst patients that had type1(n=20) type2(n=76) or type3(n=29) acromion(p>0,05). When patients were compared by matching acromion types with CAL degeneration levels, no combination had superior results to another. Conclusion: Technology has improved shoulder surgery greatly while the diagnosis and treatment of SIS is still an area that needs to be clarified and studied more. In this study, we showed that CAL degeneration level and acromion morphologic types are not good indicators for deciding whether or not acromioplasty is necessary while treating isolated SIS. This can state that intrinsic degenerative factors are more at play than extrinsic factors in the etiology of SIS. In accordance with the current literature, the fact that there is no significant difference in postoperative results between the study and control groups shows that the need for acromioplasty in isolated SIS is open to discussion.