Development and validation of subject-specific patellofemoral joint kinematic models for children and adolescents with recurrent patellar dislocation

The relationship between patellar maltracking and instability is poorly understood. Patellar maltracking can be subjectively described, but it is difficult to objectively assess using clinical tests or traditional imaging techniques. Using personalised tibiofemoral (TFJ) and patellofemoral joint (PFJ) models created from MRI, we estimated PFJ kinematics in four paediatric patients with recurrent patellar dislocation (RPD). For validation purposes, the resulting kinematics were compared against PFJ kinematics from MRI collected at four TFJ flexion angles. The developed PFJ models captured different maltracking patterns in the first 30° of TFJ flexion, where the patella is least stable. Thus, our results suggest that objectively quantifying maltracking patterns may help evaluate the risk of RPD with improved precision.