Study finds, J-sign and the BMI determines the disease-speci
A Study was conducted to determine which risk factors for patellar instability contribute most relevantly to patients’ subjective disease-specific quality of life, aiming to provide implications on the overall treatment decision-making process.

A total of 182 consecutive patients with a history of patellar instability were prospectively enrolled in this study. Patient age, body mass index (BMI), number of dislocations, reversed dynamic patellar apprehension test (ReDPAT), J-sign severity, and pathoanatomic risk factors of patellar instability were assessed.

--Analysis of the individual variables’ ability to predict BPII 2.0 score values revealed ‘age’, ‘BMI’, ‘ReDPAT’, ‘high grade of trochlear dysplasia’, and ‘high-grade J-Sign’ as possible relevant factors.

--Backward-stepwise multivariate regression analysis yielded a final parsimonious model that included the factors ‘BMI’ and ‘J-Sign (Grade II and III)’ as the most relevant parameters influencing BPII 2.0 score values, with a cutoff value for BMI found at 28 kg/m2.

The findings of this study show that a high-grade J-sign and a higher BMI have a substantial impact on subjective disease-specific quality of life in patients with lateral patellar instability.