Pain score distribution: an expert elicitation study for distal humerus hemiarthroplasty and total elbow arthroplasty using a validated numerical patient rated outcome-measure in trauma

Abstract<br/>Aims<br/>With equal numbers of adults with unreconstructable distal humerus fractures undergoing total elbow arthroplasty (TEA) and distal humerus hemiarthroplasty (DHH) a randomized trial is needed to compare the interventions. Patients have identified pain as the key outcome. There is no data on pain outcomes using a validated pain instrument to plan a trial. This study aims to use expert elicitation to produce probability distributions for the Patient Rated Elbow Evaluation Pain (PREE pain) score at 12 months in adults undergoing TEA or DHH for trauma.<br/>Methods<br/>Using the Sheffield Expert Elicitation Framework (SHELF) seven experts were recruited and provided with a summary of current knowledge on pain outcomes from a systematic review. They were asked to consider their median of the PREE pain score at 12 months after a TEA for acute trauma, their difference in the median PREE pain scores between TEA and DHH, and their standard deviation of the PREE pain score after TEA and DHH. The Rational Independent Observer concept was used to achieve consensus. <br/>Results<br/>The elicited median value for the PREE pain at 12 months after TEA for acute trauma was 13.6/50 (IQR 10.6 to 16.8). The estimated median of the difference in PREE pain scores was 3.4 (IQR -0.3 to 7.1). The elicited standard distribution of PREE pain scores was 9 (standard deviation (SD) 2.2), and after DHH was 12 (SD 3.0).<br/>Conclusion<br/>Expert elicitation can be a useful tool for synthesizing unknown probabilities. Experts’ consensus is that PREE pain scores at 12 months in patients treated with elbow arthroplasty for acute trauma would be higher following DHH than TEA, and that the pain scores for DHH patients would exhibit greater variance than patients having TEA. This difference is estimated to be small but should be tested in a randomized trial.