Causes of pain and loss of function in rotator cuff disease: analysis of 1383 cases.

BACKGROUND: The New Zealand Rotator Cuff Registry is a multicentre, nationwide prospective study of rotator cuff repairs established in March 2009.

METHODS: A total of 1383 rotator cuff repairs were included in this study, all with completed baseline Flex-SF scores, pain scores and standardized operative forms.

RESULTS: Increasing tear size and tear retraction, over 4 cm, were associated with decreasing Flex-SF scores but not pain. Tear area (a composite of tear size and retraction) is increased with advancing age, male gender and a traumatic history but not with smoking. Increased pain scores were associated with supraspinatus (SS) single tears, compared to subscapularis tears, and with labral tears. SS/infraspinatus tears had lower Flex-SF scores compared to subscapularis/SS.

CONCLUSION: This study presents the relationship between baseline function, pain and tear characteristics in symptomatic rotator cuff tears. Increasing tear size and retraction are related to a loss of function but have minimal effect upon pain. Pain generators included labral pathology, and the involvement of SS. The intraoperative appearance of the long head of biceps pathology did not predict baseline pain and function.