The minimal important difference and smallest detectable change of the Oxford elbow score, Quick disabilities of the arm shoulder and hand and single assessment numeric evaluation used for elbow trauma

Abstract

BackgroundThe Minimal Important Difference (MID) and Smallest Detectable Change (SDC) are methods used to identify the smallest changes in Patient-Reported Outcome Measures (PROMs) that are of relevance to the patients. Data on these parameters is, however, limited for elbow conditions including traumatic injuries. The aim of this study was therefore to estimate the MID and SDC for three commonly used PROMs after elbow trauma; the Oxford Elbow Score (OES), Quick Disabilities of the Arm Shoulder and Hand (QuickDASH) and Single Assessment Numeric Evaluation (SANE). Material and methodsOne hundred patients, 67 females, aged ≥18 years (mean age 52.4 years (SD, 18.2)), who had sustained a fracture, tendon rupture or dislocation affecting the elbow, completed the OES, QuickDASH, and SANE 3-5 months after injury (T1) and again after a minimum of 3 weeks (T2). A transition item with a 7-level scale, enquiring about the situation with the elbow, was also completed at T1 and T2. The difference in scores between T1 and T2 was calculated (change scores). The MID was assessed using the mean change method; a response of “slightly better” or “slightly worse” was defined as being a clinically significant change. The SDC was estimated by calculating the standard error of measurement (SEM) based on 2 administrations (1- to 3-week interval) of PROMs in a separate group of patients who had sustained an elbow injury 1 to 2 years previously. ResultsThe most common diagnosis was fracture of the proximal radius (n = 33). Eighteen patients responded slightly better and 5 slightly worse on the transition item and had mean change scores of 7.9 (9.3) for the OES and -7.4 (11.4) for the QuickDASH. Assessment of SDC was based on 56 patients having sustained an elbow injury between September 2019 and October 2020. The SDC was: 12.1 for the OES, 11.4 for the QuickDASH and 1.94 for the SANE. ConclusionChange scores need to exceed 12.1 points for the OES, 11.4 points for the QuickDASH and 1.94 points for the SANE in order to measure change with clinical relevance and not due to measurement errors.