Background: In the literature it has been shown that posterior capsule flexibility is a precursor to shoulder problems. However, no study thus far has shown the influence of the flexibility of posterior capsule in different shoulder pathologies.
Objective: This study set about to compare the role of posterior capsule tightness in different shoulder problems.
Methods: One-hundred-twenty-five patients diagnosed with shoulder subacromial impingement syndrome (n= 52), partial rotator cuff tear (n= 31) or frozen shoulder (n= 42) and 30 asymptomatic peers participated in the study. Horizontal adduction was assessed in side-lying position for posterior capsule tightness. Pain was measured via the visual analogue scale and shoulder range of motion and active total elevation was assessed with goniometer. Hand behind the back (HBB) test was assessed the active internal rotation by measuring the distance between T5 and the thumb.
Results: It was found that the affected side of the posterior capsules of the patients with subacromial impingement syndrome (p< 0.001), partial rotator cuff tear (p< 0.001) and frozen shoulder (p< 0.001) was stiffer than their healthy side. There were significant differences among groups in the level of tightness in the posterior capsule between the affected and the healthy sides (p< 0.001). All range of motion of the shoulder including HBB test and the posterior capsule tightness of the affected side are found to be correlated (p< 0.05).
Conclusions: This study emphasized that the posterior capsule's susceptibility to tightness is most evident in frozen shoulder among different shoulder problems.
Keywords: Posterior capsule; frozen shoulder; partial rotator cuff tear; shoulder impingement syndrome.