Reliability of magnetic resonance imaging findings in symptomatic minor instability of the lateral elbow: A cross-specialty evaluation.

Abstract

Symptomatic minor instability of the lateral elbow (SMILE) was recently described as an atraumatic or microtraumatic (overuse) cause of lateral elbow pain. The purpose of this study was to describe magnetic resonance imaging findings in arthroscopically confirmed SMILE and evaluate the reproducibility of predefined imaging features. It was hypothesised that standard MRI could identify recurrent structural findings associated with SMILE, although variability in interobserver agreement was expected. Patients who underwent elbow arthroscopy for the treatment of atraumatic recalcitrant lateral elbow pain between 2021 and 2024 by the same surgical team were retrospectively included in this study. Inclusion criteria were arthroscopic identification of a minimum of three signs of minor instability, and available preoperative MRI images. The preoperative MRI images were independently evaluated by five raters (three orthopaedic surgeons and two specialised musculoskeletal radiologists). Prevalence, inter-rater reliability, intra- and inter-group agreement were calculated for each finding. The significance level was set at <i>p</i> = 0.05. Thirteen patients were included in the study. The kappa coefficient values ranged from 0.036 (95% confidence interval [CI], -0.14 to 0.21) to 0.412 (95% CI, 0.24 to 0.58), indicating fair to moderate agreement across findings. Common extensor partial tear in Coronal T2 or PD FS was the only considered both prevalent and reliable. MRI findings in arthroscopically confirmed SMILE demonstrated variable interobserver reproducibility, with only selected features showing acceptable agreement. While standard MRI may identify structural changes associated with SMILE, the limited reproducibility of several findings highlights the need for standardised imaging criteria and further investigation, including advanced imaging techniques such as intra-articular imaging techniques. Level III, retrospective diagnostic reliability study.