The purpose of this study was to investigate the influence of the variance of posture on shoulder pain and rotator cuff tears. A medical checkup was conducted for the residents of a mountain village in Gunma prefecture. The subjects consisted of 525 people including 1050 shoulders; 193 males including 386 shoulders and 332 females including 664 shoulders, with a mean age of 61.9 years old. We took their side view picture in a standing position, and divided them into 5 types according to the classification of Nakatani; normal (type 1), thoracic kyphosis (type 2), lumbar kyphosis (type 3), flat back (type 4), lumbar lordosis (type 5). We examined their background factors, physical examinations and ultrasonographic diagnosis of rotator cuff tear on both shoulders. We elucidated the prevalence of shoulder pain and rotator cuff tears with respect to each variance of posture. Additionally the subjects were divided into 2 groups; namely a Normal group (type 1), and a postural abnormality group (type 2-5). The differences between the 2 groups were evaluated.
The normal type was present in 50.1%, thoracic kyphosis type in 24.6%, lumbar kyphosis type in 4.2%, flat back type in 6.7%, and lumbar lordosis type in 14.5%. Residents having shoulder pain frequently demonstrated thoracic kyphosis, flat back and lumbar lordosis. In addition, residents having rotator cuff tears frequently demonstrated thoracic kyphosis and lumbar kyphosis. The postural abnormality group was most commonly associated with elderly patients, who showed a decreased active forward elevation, a weaker external rotation strength, a positive finding for impingement sign and a decreased QOL. A logistic regression analysis revealed age, gender, present shoulder pain, an active forward elevation and EuroQOL (5 item) to all be significantly associated with an abnormality in the posture of these subjects.
