Development and Content Validation of the Questionnaire for Postamputation Pain (Q-PAP): An Expert Delphi Study

The questionnaire for postamputation pain (Q-PAP) introduced here has undergone modifications over a decade of research on postamputation pain. It has so far been used as a form of study specific questionnaire. Here, we present the latest attempt to consolidate it as a tool useful for both research and clinical practice by involving experts on postamputation pain worldwide.

A three-round Delphi study was conducted online, utilising email and digital forms as tools for communication and providing feedback. We included a purposive sample of 13 clinicians and researchers with expertise in postamputation pain from eight countries. The experts ranked each questionnaire item for relevance, clarity, and completeness on a 5-point Likert scale. Consensus on each item was considered reached when the level of agreement was above 50%.

The preliminary version of the Q-PAP comprised an introduction and sections with questions on phantom limb pain, residual limb pain, neuroma pain, and situational changes. Based on the group's feedback, the section on neuroma pain was removed, as it required clinician-administered tests, which conflicted with the self-report nature of the questionnaire. In addition, individual items on telescoping, prosthesis use, and bone pain were removed, as experts deemed them too specific. The final version of the Q-PAP assesses pain intensity, descriptors, frequency, interference, phantom limb position, phantom limb movements, phantom limb sensation, and situational changes.

The findings support content validity of the Q-PAP as a self-report instrument for the multidimensional assessment of postamputation pain, providing a clinically relevant and patient-centred tool for capturing key pain characteristics and experiences. The psychometric validation of the Q-PAP is a crucial part of future work, establishing its reliability, validity, and comparability for use in PAP research and clinical practice.