There are very few studies in the literature about conservative treatment of massive rotator cuff (RC) tears. Whether the treatment of massive RC tears is conservative or surgical is decided according to the age, activity level, expectation and additional pathologies of the patient. The aim of conservative treatment is to make the patient functionally independent and to reduce pain. In recent years, there are different opinions in the literature about the effectiveness of conservative treatment of massive RC tears. However, in recent biomechanical studies, it has been reported that the RC and the deltoid, which remain intact in massive RC tears, can function well together.

The hypothesis of this study is that the deltoid-focused physiotherapy program, where strengthening exercises are performed with EMG biofeedback, will give more positive results in terms of range of motion (ROM), functional status, muscle strength, pain and patients satisfaction. aim of our study is to investigate the efficacy of electromyographic biofeedback (EMG-BF) device which was added to deltoid focused conservative treatment program in massive RC tears.

Inclusion Criteria:

• Unilateral, non-traumatic massive rotator cuff tears according to Deorio and Cofield classification
• Age older than 50 years and attend 1-year follow-up assessment

Exclusion Criteria:

• Patients with symptomatic lesions in the contralateral shoulder
• Cuff tear arthropathy
• Glenohumeral osteoarthritis
• Pseudoparalytic shoulder
• Grade 3-4 fatty degeneration according to Goutallier classification
• History of involved shoulder surgery
• Major systemic conditions that disallowing exercise