Factors involved in the presence of symptoms associated with rotator cuff tears: a comparison of asymptomatic and symptomatic rotator cuff tears in the general population.

BACKGROUND

The mechanisms underlying symptom development in rotator cuff tears are still unknown. The purpose of this study was to identify the characteristics associated with symptoms of rotator cuff tears.

MATERIALS AND METHODS

We performed a medical checkup on residents of a mountain village. The subjects of this study included 211 individuals with 283 shoulders in which a full-thickness rotator cuff tear was observed through ultrasonography. We recorded the subjects' background and medical history and then performed physical examinations. The subjects were divided into 2 groups according to whether they had any pain or disabilities that they felt subjectively while performing their usual daily activities. We determined the prevalence of an asymptomatic rotator cuff tear and conducted a statistical analysis to compare any differences between the 2 groups.

RESULTS

Of the 283 subjects, 65.4% with rotator cuff tears had no symptoms involving the shoulder. Asymptomatic rotator cuff tears were associated with a tear in the nondominant arm, a negative impingement sign, higher active forward elevation, and intact muscle strength in abduction and external rotation. A logistic regression analysis showed that a positive impingement sign, weakness in external rotation, and presence of a tear in the dominant arm were significantly associated with the presence of symptoms of rotator cuff tears.

CONCLUSIONS

In the general population, in approximately two-thirds of all rotator cuff tears, there are no symptoms, and the factors involved in the presence of symptoms associated with rotator cuff tears were identified to be a positive impingement sign, weakness in external rotation, and presence of a tear in the dominant arm.