We compared the ceiling effects of two patient-rating scores, the Disability of the Arm, Shoulder and Hand (DASH) and Patient-Rated Wrist Evaluation (PRWE), and a physician-rating score, the Modified Mayo Wrist Score (MMWS) in assessing the outcome of surgical treatment of an unstable distal radial fracture. A total of 77 women with a mean age of 64.2 years (50 to 88) who underwent fixation using a volar locking plate for an unstable distal radial fracture between 2011 and 2013 were enrolled in this study. All completed the DASH and PRWE questionnaires one year post-operatively and were assessed using the MMWS by the senior author. The ceiling effects in the outcome data assessed for each score were estimated. The data assessed with both patient-rating scores, the DASH and PRWE, showed substantial ceiling effects, whereas the data assessed with MMWS showed no ceiling effect. Researchers should be aware of a possible ceiling effect in the assessment of the outcome of the surgical treatment of distal radial fractures using patient-rating scores. It could also increase the likelihood of a type II error. Cite this article: Bone Joint J 2015;97-B:1651–6