DEgenerative ROtator Cuff Disease and Botulinum TOXin

Epidemiology: degenerative rotator cuff disease ranks first in shoulder disorders and is the main cause of chronic shoulder pain in general practice and in rheumatology clinics. It can be responsible for persistent shoulder pain, functional limitation and greatly contributes to occupational disability. The pathogenesis of rotator cuff disease: involves tendon impingement and intrinsic tendinopathic abnormality (supra-spinatus, infra-spinatus, teres minor and sub-scapularis muscles). They include apoptosis of the tenocytes that is induced by mechanical constraints and by local hypoxia. The consequences are secondary inflammation and matrix alteration. Current therapeutic approach: The first-line recommended treatment for degenerative rotator cuff disease is conservative and includes level 1 and 2 oral analgesics; a short sequence of nonsteroidal anti-inflammatory drugs, if necessary; local injections of corticosteroids; and physiotherapy (low level of evidence). Surgery is a conditional later option. Study hypothesis: Reducing mechanical constraints on the supra-spinatus tendon by botulinum toxin may prevent load-induced apoptosis of the tenocytes and tear progression that is associated with clinical expression, and prevent local hypoxia. Furthermore, the muscle inactivity induced by botulinum toxin is not awaited to provide any clinically relevant functional alteration. Aim of the study: The primary objective of the study is to assess the effectiveness of botulinum toxin in persistent shoulder pain due to degenerative rotator cuff disease at one-month follow-up, using Shoulder Pain And Disability Index (SPADI) as outcome criterion. The secondary objective is to assess the effectiveness of botulinum toxin in persistent shoulder pain due to degenerative rotator cuff disease, at three-month follow-up, using SPADI as outcome criterion and safety, the SPADI sub-scores pain and function at 3 months, global improvement perceived at 1 month and 3 months, drug consumption over the 3 months of follow-up, and treatment acceptability at 1 month and 3 months; as well as the tolerance at 1 week.