Background
The clinical outcomes of arthroscopic rotator cuff repair (ARCR) have recently improved, but re-tear still occurs in some cases. This study was performed to investigate the factors that influence the clinical outcomes of re-tear cases after ARCR.
Materials And Methods
In total, 108 shoulders with large and massive rotator cuff tears were enrolled in this study and followed up for more than 2 years after ARCR. Clinical assessments were performed using the Japanese Orthopedic Association (JOA) score, Constant score, and active elevation angle. Imaging was performed to investigate the morphology of the rotator cuff tear, fatty infiltration, muscle atrophy, upward migration of the humeral head, and tendon healing. To investigate the morphology of the rotator cuff tear, the medial–lateral diameter, anterior–posterior diameter, area, and distance from the rotator cuff stump to the scapular glenoid fossa were evaluated by magnetic resonance imaging (MRI) before and after ARCR. To evaluate the fat infiltration of the rotator cuff muscle, the Goutallier classification was used to determine the stage of the supraspinatus, infraspinatus, and subscapularis muscles at the Y-view position of the MRI oblique sagittal image before and after ARCR. To evaluate muscle atrophy, the muscle cross-sectional area was measured at the same slice on MRI before and after ARCR. Upward migration of the humeral head was evaluated by the Oizumi classification on X-ray imaging and MRI and was determined by the distance between the acromion and humeral head on the X-ray before and after surgery. The MRI Sugaya classification was used to evaluate the occurrence of re-tear, which was defined as type IV and V. For statistical examination, the Mann–Whitney U test was used for comparison between the two groups, and the risk rate was 5%.
Results
Re-tear was observed in 28 shoulders (re-tear rate of 25.9%), of which 4 shoulders had undergone reoperation. The 28 shoulders were divided into 2 groups according to the performance of reoperation: Group N comprised 24 shoulders that did not undergo re-surgery, and Group R comprised 4 shoulders that underwent re-surgery. Group N and Group R showed significant differences in the JOA score (83.6 and 63.6 points, respectively), Constant score (81.4 and 60.2 points, respectively), and active flexion angle (127.1 and 51.3 degrees, respectively). In the imaging evaluation, a significant between-group difference was observed only in the difference in the anterior–posterior diameter between the preoperative and final observations. In Group N, the anterior–posterior diameter decreased by an average of 21.5 mm between the preoperative and final observations, but in Group R, an average reduction of only 3.7 mm was observed.
Conclusion
These findings suggest that it is important to use a repair method that does not expand the anterior–posterior diameter even if re-tear occurs after surgery.