Reverse shoulder arthroplasty (RSA) was developed by Grammont to address cuff tear arthropathy (CTA) in the elderly. RSA facilitates centring of the humeral head within the glenoid, such that deltoid function is maintained. CTA remains the main indication for RSA but observed improvements in postoperative outcomes have driven an expansion of indications. This review explores the broadening role of RSA, with emphasis on non-traumatic indications. In addition, the biomechanical principles, evolution of reverse polarity prostheses and complications are discussed.