AOSSM 2022 Annual Meeting Recordings - no CME-The J- Sign in Patients with Patellofemoral Instability

Video Transcription

Video Summary

The video discusses the J sign, which is considered visual evidence of patellar maltracking. Initially associated with VMO deficiency and patellar tilt on imaging, there is now a better understanding of other contributing factors. The severity of the J sign varies and attempts have been made to quantify and grade it. However, reliability in quantifying the J sign is not strong. Studies on the J sign have shown correlations with lateral patellar translation, MPFL reconstruction failure, lower PRO scores, and inferior outcomes after surgery. Risk factors for a high-grade J sign include femoral antiversion, external tibial torsion, and patellar alta. Trochlear dysplasia is a common factor in patellar femoral instability but is not reliably measured. The video also discusses the Jupiter cohort study, which aims to understand the factors influencing the J sign. Factors that correlated with the presence of a J sign include effusion, patellar translation, ligamentous laxity, and knee hyperextension. Imaging variables such as patellar articular length and the presence of a trochlear bump were also considered. Patellar alta was identified as a strong factor in the J sign. Femoral antiversion and trochlear dysplasia require further study. The video acknowledges Bob Magnuson, Brilliant Methods, Beth Schubenstein, Shital Parikh, and the Jupiter investigators and research team for their contributions to the study.

Asset Caption

Jacqueline Brady, MD

Keywords

J sign

patellar maltracking

VMO deficiency

patellar tilt

lateral patellar translation