Magnetic resonance arthrography of the hip: prevalence of diagnoses not suspected by the referring physician and correlation with clinical examination and pain score

Abstract

Background Magnetic resonance arthrography (MRA) of the hip is the most sensitive imaging modality for intra-articular pathologies such as labral tears. Purpose To evaluate the prevalence of non-suspected pathologies revealed by hip MRA and correlate them to physical examination/pain level. Material and Methods All hip MRAs (2011–2013) were retrospectively evaluated for intra- and extra-articular pathologies in consensus by two readers. A clinical score (0–7)/pain score (0–10) was calculated for each patient based on orthopedic test results extracted from referral forms/a telephone questionnaire. Patients were divided into four groups according to MRA findings: intra-articular expected (targeted) pathology only; intra-articular targeted and additional non-targeted (unexpected) pathology; non-targeted pathology; and no pathology. Pathologies prevalence/clinical score/pain score were compared between the groups. Results A total of 229 MRAs were included (127 men, 102 women; mean age, 36.5 ± 14.17 years): 111(48.4%) patients had solely intra-articular targeted pathology. Significant non-targeted pathologies were detected in 76 (33%) patients (targeted and non-targeted, 51; non-targeted only 25). No significant pathology was detected in 42 patients (18%). Mean physical examination score was 2.77 ± 1.77, range 0–7. There was no significant difference or correlation (r = 0.017, P = 0.804) between the clinical scores of the different MRA pathology groups. Pain score (143 patients) was significantly higher in the non-targeted pathology group compared to the targeted and non-targeted group ( P = 0.04) and to the no pathology group ( P = 0.04). There was no correlation between the physical examination score and the pain score (r = 0.017, P = 0.804). Conclusion Unsuspected non-targeted pathologies were detected in 33% of hip MRA. Physical examination/pain level could not differentiate between patients.