Development and validation of a questionnaire assessing discrepancy between patients’ pre-surgery expectations and abilities and post-surgical outcomes following knee replacement surgery

Purpose - The discrepancy between patient-desired outcomes and achievable functional outcomes is a source of patient dissatisfaction. This paper reports development and validation of a questionnaire to assess this discrepancy in patients undergoing knee replacement surgery. Methods - The initial questionnaire (Knee Surgery Perception Questionnaire, KSPQ) comprised two parts. Part A, assessed patients’ perception of their current level of function and pain, and Part B, assessed patients’ desired outcomes of the surgery. Validation was carried out for Part A and then applied to Part B using a one-factor congeneric model and was tested in 185 patients preceding surgery. A discrepancy score between patients’ expectations and desired outcome (Part B) and their perception of current function (Part A) was also calculated. Pearson correlations were used between the KSPQ total score and subscales and other knee-specific questionnaires to determine construct validity. Results - The final best set of models included four items for each subscale with a Chi-square value of 7.3 (n.s). The subscales and the total KSPQ showed significant strong to moderate correlations with knee-specific questionnaires. The discrepancy score in each subscale and the overall score showed relatively large discrepancy between patients’ expectations and their perception of current function; with higher discrepancy score reported for pain and walking. Conclusion - The KSPQ is a valid questionnaire to assess patients’ expected and desired outcomes of knee replacement surgery and their perception of their current abilities and function, and discrepancy between these. The KSPQ now requires further investigation at different stages of recovery following surgery