Brachial plexus Injury (BPI) occurs following trauma to the nerves as they exit the spinal cord in the neck. Dependent on the site and degree of the initial trauma, people with BPI display a board spectrum of ability to use their affected arm to perform day-to-day activities. BPI is a heterogeneous condition that has a significant impact on how the individuals use their arm. Some may only achieve simple stabilising or carrying tasks; others may undertake more complex movements that use the whole arm and hand. Historically, outcomes following adult traumatic BPI have been discussed in terms of impairments such as strength or range of motion. Despite evidence of good outcomes, people still report on-going dissatisfaction with the day-to-day use of their arm. Using the International Classification of Functioning Disability and Health (ICF) as a framework, a systematic review of the literature was undertaken to identify all patient-reported outcome measures that predominantly assessed activity. Two patient-reported outcome measures were identified, yet neither had been psychometrically evaluated for BPI. Further, they did not appear to include the range of activities required to assess the full spectrum of ability seen in adults with BPI, particularly for those with limited arm use. Seventeen additional outcome measures were identified that had been developed by experts solely for a research purpose, lending support for a new BPI outcome measure in the clinical setting.