Reliability of a Novel Scoring System for MRI Assessment of Severity in Gluteal Tendinopathy: The Melbourne Hip MRI Score

Background: Gluteal tendinopathy is commonly reported in the literature, but there is a need for a validated magnetic resonance imaging (MRI)-based scoring system to grade the severity of the tendinopathy. Purpose: To use intra- and interobserver reliability to validate a new scoring system, the Melbourne Hip MRI (MHIP) score, for assessing the severity of gluteal tendinopathy. Study Design: Cohort study (diagnosis); Level of evidence, 3. Methods: The MHIP score assesses gluteal tendinopathy according to each 1 of 5 categories: (1) extent of tendon pathology (maximum 5 points); (2) muscle atrophy (maximum 4 points); (3) trochanteric bursitis (maximum 4 points); (4) cortical irregularity (maximum 3 points); and (5) bone marrow edema (maximum 1 point), with an overall range of 0 to 17 (most severe). A total of 41 deidentified MRI scans from 40 patients diagnosed with gluteal tendinopathy (mean baseline age, 57.44 +/- 25.26 years; 4 male, 36 female) were read and graded according to MHIP criteria by 2 experienced musculoskeletal radiologists. The radiologists were blinded to previous reports, and the scans were read twice within a 2-month period. Statistical analysis using the intraclass correlation coefficient (ICC) was used to determine intra- and interobserver reliability and mean/range for the MHIP scores. Results: Of a total of 123 readings, the mean MHIP score (+/- SD) was 3.93 +/- 2.24 (range, 0-17 points). The MHIP score demonstrated excellent reliability for determining the severity of gluteal tendinopathy on MRI. The ICC for intra- and interobserver reliability was 0.81 (95% CI, 0.67-0.89) and 0.78 (95% CI, 0.62-0.87), respectively. Conclusion: The MHIP score had excellent intra- and interobserver reliability in scoring gluteal tendinopathy. This score allows gluteal tendon pathology to be graded prior to treatment and to be used for standardized comparisons between results in future research undertaking radiological review of gluteal tendinopathy.