Assessing the outcome of disorders of the hand. Is the patient evaluation measure reliable, valid, responsive and without bias?

Abstract

The different attributes of the Patient Evaluation Measure (PEM) questionnaire were investigated in 80 patients with a fracture of the scaphoid. Assessments were made at 2, 8, 12, 26 and 52 weeks. Reliability was assessed by measurement of the internal consistency of the different questions in 275 completed PEM forms. Cronbach's alpha, which needs to lie between 0.7 and 0.9, was 0.9 for the PEM. Pain, tenderness, swelling, wrist movement and grip strength correlated with the PEM score confirming the validity of the assessment. Changes in the different variables between visits correlated significantly with changes in the PEM score; its effect size and standardised response mean were comparable to those of grip strength and movement, confirming the responsiveness of this questionnaire. Gender, dominance and the side injured did not influence the scores. Older patients had a poorer outcome as assessed by the score which appeared to be a true effect and not age bias. Our study confirmed that the PEM is a reliable, valid and responsive instrument in assessing outcomes of disorders of the hand.