Superior Capsular Reconstruction vs. Partial Repair for Massive Rotator Cuff Tears

Inclusion Criteria: * Symptomatic shoulder pain and/ or weakness (regardless of baseline range of motion/ psuedoparalysis) * Massive rotator cuff tear, identified by MRI as being greater than 4 cm in greatest diameter, and involvement of the entire supraspinatus and infraspinatus. * Failure of at least a 3 month trial of non-surgical treatment including physiotherapy and activity modifications * Irreparable tear determined intra-operatively using standard arthroscopic techniques * Informed consent obtained Exclusion Criteria: * Absence of subscapularis muscle insertion, or irreparable subscapularis tear * Advanced rotator cuff tear arthropathy (Hamada Grade 3+) or glenohumeral osteoarthritis (Samilson-Prieto grade 2+) * Acute tears (within 6 months) * Neurologic injury causing paralysis of affected shoulder / arm * Any previous surgery to the affected shoulder * Limited life expectancy due to significant medical co-morbidity or medical contraindication to surgery (ASA Grade IV or higher) * Anticipated problems with ability to maintain follow-up in the judgement of the investigators (ie. patients with no fixed address, etc.) * Are there any non-orthopedic comorbidities that put the patient at significant risk?