Femoroacetabular impingement in amateur athletes: The value of response to anaesthetic injection during hip MR arthrography

Abstract

Purpose: Femoroacetabular impingement (FAI) represents a common aetiology of hip pain. The purpose of the present study was to prospectively evaluate MR imaging findings and intra-articular block results in amateur athletes presenting with symptoms of FAI that were treated arthroscopically. Material and Methods: During a five-year period (January 2014 to January 2019), 197 amateur athletes (116 male, 81 female, aged 18-54 years, mean age 33 years) presented with symptoms of hip pain and were referred with the possible diagnosis of FAI. After careful clinical evaluation 27 of them met the diagnostic criteria of FAI and were subsequently studied with direct MR Arthrography (MRA) in combination with intra-articular block. Patients were consequently treated by means of arthroscopy. MRA findings and Visual Analog Scale (VAS) scores pre and post intra-articular block were recorded and were analysed to verify the clinical suspicion of impingement. Results: FAI was verified in all patients (27/27, 100%). Labral tears were depicted in 23 patients (85.2%) by arthroscopy. High sensitivity and specificity were recorded for MRA regarding labral tears (96% and 85% respectively). Evaluation of intra-articular blocks showed high positive predictive value (PPV) and accuracy for the diagnosis of intra-articular pathology (PPV: 92%, accuracy: 96.5%). The mean pain scores pre and post intra-articular blocks were 8 and 2 respectively. Conclusions: MR arthrography in combination with intra-articular block showed high sensitivity and specificity for the diagnosis of FAI syndrome.