The J-sign and the body mass index determine the disease-specific quality of life in patients with lateral patellar instability.

Purpose: 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.

Methods: A total of 182 consecutive patients (male/female 70/112; mean age 23.6 ± 7.