Reliability of New Radiographic Measurement Techniques for Elbow Bony Impingement

BACKGROUND: Identifying the location and scale of radiographic changes in elbow bony impingement (EBI) is critical in formulating an appropriate diagnosis and treatment plan for such patients. The purpose of present study was to evaluate the intra-rater and inter-rater reliability of the new radiographic parameters, Anterior Impingement angle (AIa) and Posterior Impingement angle (PIa), for EBI. In addition, to determine if there was a relationship between radiographic parameters and clinical evaluation. PATIENTS AND METHODS: Three raters of different levels of training evaluated the radiographs of 60 patients (30 in EBI group and 30 in normal group) twice, at least 2 weeks apart. Intra-rater and inter-rater reliabilities were calculated by Intraclass Correlation Coefficients (ICC) with 95% confidence intervals. Correlation between radiographic parameters and clinical evaluation was calculated by Pearson correlation coefficient. RESULTS: In both groups, intra-rater and inter-rater reliabilities were substantial. There were no significant differences in reliability between upper-hand expert surgeons and resident for either measurement. Good correlation was observed between impingement arcs and range of motion values. CONCLUSIONS: Both AIa and PIa measurements demonstrated substantial intra-rater and inter-rater reliability for normal radiographs and in EBI patients. Good reliability, for either expert surgeons or residents in training, and good correlation between radiographic measurements and manual testing, appoints this method may be easily and reliably used in every day practice.