Bone Shape Feature Differences in Single and Recurrent Patellar Dislocations via Statistical Shape Modeling

This study aims to develop MRI-based 3D statistical shape models for patellar dislocation patients and investigate bone shape features that distinguish between single and recurrent dislocation populations, as well as control and patellar dislocation populations. MRIs from 16 single dislocation patients, 17 recurrent dislocation patients, and 20 control subjects were used to build statistical shape models for femur and patella bones. Bone shape features were extracted and tested for statistical significance (p < 0.05) for distinguishing the single dislocation group from the recurrent dislocation groups, and the control group from the dislocation group. Statistically significant shape features distinguishing the three groups were identified for both bones. A shallower trochlear groove and smaller patellar ridge told the dislocation groups apart from the control group. A prolonged lateral condyle in femur and a laterally shifted ridge and hood shaped lateral facet in patella distinguished the recurrent dislocation group from the single dislocation group. The study's findings from 3D statistical shape modeling of the femur and patella reveal distinct anatomical differences across control, single dislocation, and recurrent patellar dislocation groups. This advanced understanding aids in identifying individuals at higher risk for initial or recurring patellar dislocations, enabling clinicians to tailor treatment and management strategies more effectively to prevent further dislocations and mitigate potential patellofemoral joint damage.