Factors related to successful outcome of conservative treatment for rotator cuff tears

Background. Much controversy exists as to the management of full-thickness tears of the rotator cuff. Not all patients with rotator cuff tears require surgical treatment. We have little information whether there are factors that are related to successful outcome of conservative treatment. Aim. The purpose of this study was to determine the factors related to the successful outcome following conservative treatment. Methods. This study included 123 shoulders in 118 patients with full-thickness tears of the rotator cuff diagnosed by high-resolution magnetic resonance imaging with a microscopy coil. All patients were treated conservatively for at least 3 months. Clinical symptoms improved in 65 shoulders in 62 patients by conservative treatment (conservative group), but remained unchanged or aggravated in 58 shoulders in 56 patients, who eventually underwent surgical repair (surgical group). Results. The following parameters showed significant differences: 1) integrity of the intramuscular tendon of the supraspinatus (24.1% in the surgical group and 58.4% in the conservative group showed an intact intramuscular tendon); 2) supraspinatus muscle atrophy (occupancy ratio was 69.8% in the surgical group and 78.0% in the conservative group); 3) impingement sign (positive in 79.3% in the surgical group and 30.7% in the conservative group); and 4) external rotation angle (35.0 degrees in the surgical group and 52.2 degrees in the conservative group). The success rate of conservative treatment was 87% in the cases with at least three of these four factors. Conclusion. These four factors are useful in selecting patients who will respond well to conservative treatment before initiating the treatment.