Background: A retear after rotator cuff repair is a common problem; however, there is little information related to the prognosis after a retear. In addition, some patients with retears have satisfactory outcomes, which raises the question of whether a retear leads to a poor prognosis.
Purpose: To identify radiological factors that influence the prognosis after a retear.
Study design: Case-control study; Level of evidence, 3.
Methods: A total of 51 patients with retears confirmed by magnetic resonance imaging at 1 year after arthroscopic rotator cuff repair with a minimum follow-up of 24 months were enrolled in this study. Patients were divided into 2 groups according to whether they achieved the minimal clinically important difference for clinical outcome measures. Range of motion and radiological variables, including preoperative and postoperative anteroposterior (AP) and mediolateral (ML) tear sizes, sagittal extent of the retear, acromiohumeral distance (AHD), and degree of fatty degeneration, were analyzed using magnetic resonance imaging.
Results: Overall, 36 patients were allocated to the good prognosis (GP) group and 15 to the poor prognosis (PP) group. The 2 groups had no significant differences in baseline demographics and preoperative radiological parameters. Postoperative range of motion was decreased in the PP group at the last follow-up. The AP and ML retear sizes decreased in both groups after arthroscopic rotator cuff repair, but the retear size was significantly larger in the PP group (both P < .05). The AHD increased in the GP group (P < .001) but decreased in the PP group (P = .230) postoperatively. Logistic regression analysis revealed that postoperative AHD (P = .003), fatty degeneration of the infraspinatus tendon (P = .001), posterior (P = .007) and anterior (P = .025) sagittal extent of the retear, and change in the AP tear size (P = .017) were related to poor outcomes after a retear. However, change in the ML tear size (P = .105) and middle sagittal extent of the retear (P = .878) were not related to a poor prognosis. Also, further analysis showed that posterior (P = .006) and anterior (P = .003) sagittal extent of the retear were related to rotator cable involvement.
Conclusion: An increased AP retear size and decreased AHD were radiological parameters that were associated with poor clinical outcomes after a retear. In particular, patients who had posterior and anterior sagittal extent of the retear, possibly with rotator cable involvement and more severe fatty degeneration of the infraspinatus tendon, showed worse outcomes.
Keywords: acromiohumeral distance; minimal clinically important difference; retear; rotator cable; rotator cuff.