Proximal radioulnar joint (PRUJ) pathology is an uncommon cause of rotational stiffness and can sometimes result in severe functional disability. At the milder end of the spectrum, PRUJ lesions involve peri-radial soft tissue adhesions, either isolated or as a part of global elbow stiffness. Bony involvement can result in a mechanical impingement and restricted arc of pronation-supination movement. Arthroscopy of PRUJ is a minimally invasive technique for visualization and excision of the impinging bony lesions and is associated with good functional outcomes. Arthroscopic access to PRUJ is possible by releasing the annular and quadrate ligaments, and the scarred soft tissues and impinging bone spurs in the sub-radial head zone can be safely resected. A ‘radial head portal’ is useful for both viewing and working in this region in combination with standard anterolateral and anteromedial portals.