1053 Comparing MRI Parameters in Quantifying Patellofemoral Instability

Abstract

Abstract Aim Patellofemoral instability is where various stabilising factors of the patellofemoral joint undergo pathomorphological changes. It has an incidence rate of 5.8 per 100,000 in UK and has been associated with osteoarthritis[1]. Variations in the factors that stabilise the patellofemoral joint can be observed on MRI including measurements of the trochlea in relation to the patella, the femur and soft tissue changes. This study aims to compare different measures used to detect and quantify patellofemoral instability on MRIs and to look for any significant difference in their use both in isolation and together. Method 109 MRI reports of 78 patients diagnosed with patellofemoral instability were reviewed and all quantitative and qualitative parameters reported were inputted in a data table. Quantitative elements known as the Dejour protocol included the trochlear sulcus angle, patellar tilt angle, tibial tuberosity-trochlear groove distance and the Insall-Salvati ratio. Qualitative factors involved facet changes, patellar position, and any damage to soft tissue. Results It was found that the Insall-Salvati ratio greater than 1.2 and the patellar tilt angle of greater than 11 degrees irregular ranges had the greatest incidence in the MRI reports found 77.1% and 87.6% respectively in MRIs that reported them. Conclusions There is a discrepancy between quantitative parameters in their correlation with patellofemoral instability for the MRI reports observed. [1]: Ye Q, Yu T, Wu Y, Ding X, Gong X. Patellar instability: the reliability of magnetic resonance imaging measurement parameters. BMC Musculoskeletal Disorders. 2019;20(1).