Comparação clínica e radiográfica entre os Portais Ântero-Inferior e Subescapular no tratamento Artroscópico da instabilidade do ombro

Abstract

Shoulder dislocation is the most frequent instability among the large joints, which can lead to functional incapacity, pain and decreased quality of life. It occurs mainly in young and active population. In most of the cases surgical treatment is recommended. The arthroscopic repair of the Bankart lesion evolved and obtained results comparable to the gold standard, the open repair. The arthroscopic approach of anterior recurrent shoulder dislocation should consider placing the anchor in the most distal and orthogonal position possible and also the risk of injury to vascular and nerve structures of the anterolateral region. Traditionally, the anterior anchors in the glenoid are placed through the anteroinferior arthroscopic portal. Due to numerous disadvantages, the subscapular portal has been widely used. It is safe, allows optimal angulation and is reproducible. Despite the advantages and disadvantages of the anteroinferior and subscapular portal approach, few studies compare the postoperative results of these two approaches in a long follow-up. The aim of this study was to compare clinical results, complication rate and metallic anchor position, when placed through an anterior-inferior portal versus a trans-subscapularis portal in the arthroscopic treatment of shoulder instability. It was a case-control observational study, performed beetween 2014 and 2016 with 33 patients who underwent arthroscopic treatment of shoulder instability were evaluated and divided into two groups: case group (n=17), in wich the anchors were placed through a trans- subscaularis portal, and control group (n=16), in wich the anchors were placed through the anterior-inferior portal. Clinical outcomes were assessed through Constant, ASES (American Shoulder and Elbow Surgeons) and UCLA (University of California-Los Angeles) scores. Subscapularis muscle strength was measured with an electronic dinamometer (Micro FET 2, Hoggan Scientific LLC) and the anchor placement was evaluated through anteroposterior and lateral radiographs. The data obtained was analyzed using the student’s t test (quantitative data) and Fischer’s test (qualitative data). Statistical significance was established at p<0,05. Anchors placed through a trans-subscapularis portal were better positioned (p<0,001) and closer to the glenoid’s inferior pole (p<0,0189) in comparison with those placed through anterior-inferior portal. The clinical outcomes were similar between both groups. The anchors were better positioned in the anterior-inferior edge of the glenoid, with an inclination angle closer to the orthogonal position when the trans-subscapularis portal was used. Furthermore, the trans-subscapularis portal was safe in regard to neurovascular structures and did not seem to implicate any functional repercussion in subscapularis muscle. Despite the better anchor placement seen on radiographs, no improvement in clinical outcomes was observed in the case group when compared with the control group.