Preoperative and postoperative magnetic resonance arthrograms in shoulders after arthroscopic and open anterior stabilization in a prospective, randomized, clinical trial (SS-28)

To evaluate preoperative gadolinium-enhanced MR arthrograms (MRA) with MR arthrograms obtained six months postoperatively in shoulders that have undergone either arthroscopic or traditional open anterior stabilization using a bioabsorbable suture anchor in a prospective, randomized clinical trial. Sixty consecutive patients who presented with chronic anterior shoulder instability who failed at least six months of nonoperative treatment were randomized to either arthroscopic or open stabilization groups. All patients underwent MR arthrograms preoperatively, the findings of which were compared to intraoperative pathology. Six months following anterior stabilization, 45 of the 60 patients underwent a second MR arthrogram to assess 1) postoperative changes in comparison to the pathology noted on preoperative studies, 2) the postoperative MRA differences between open and arthroscopic stabilization, 3) early clinical results in comparison to postoperative MRA changes. Intraoperative findings correlated well with pathological changes noted on preoperative MRA. In 90% of the postoperative shoulders at MRA, a type I “seamless” anatomical restoration of the capsulolabral complex was noted regardless of operative technique. In 10% of the cases, a type II “cleft” or type III “noncontiguous” capsulolabral attachment site was noted. These MR findings, however, did not correlate well with clinical results, subjective shoulder ratings or patients’ perception of stability. Preoperative MR arthrograms in shoulders with anterior instability allow an accurate diagnosis of intra-articular pathology that correlates well with operative findings. Arthroscopic and open stabilization techniques result in similar intra-articular findings by MRAs at six months postoperatively. The MRA studies that demonstrated less than anatomical restoration of the capsulolabral complex postoperatively correlated poorly with subjective and objective clinical outcomes.