Assessing Trochlear Dysplasia With the Novel Lateral Trochlear Anterior Condyles Angle

Area of Science:

• Orthopedics
• Radiology
• Biomedical Engineering

Background:

• Trochlear dysplasia (TD) is a significant risk factor for patellar dislocation (PD).
• Accurate quantification of TD is crucial for understanding PD risk.
• Existing TD measurement methods have limitations.

Purpose of the Study:

• To introduce and validate the lateral trochlear anterior condyles (LTAC) angle as a novel measurement for TD.
• To test the hypothesis that lower LTAC angles are associated with PD and recurrent PD (RPD).

Main Methods:

• A retrospective case-control study compared pediatric patients with PD to controls.
• The LTAC angle was measured on MRI at four axial levels of the trochlear groove.
• Subgroup analysis compared patients with one-time PD (OPD) and RPD.

Main Results:

• Significantly lower mean LTAC angles were found in PD cases compared to controls across all measured levels (P < .001).
• Patients with RPDs had significantly lower cartilaginous LTAC values than those with OPDs (P < .05).
• Osseous LTAC values showed no significant difference between RPDs and OPDs at proximal levels.

Conclusions:

• The LTAC angle is a simple, comprehensive, and reproducible measure for TD.
• Lower LTAC angles are consistently associated with patellar dislocation.
• The LTAC angle can help stratify patients based on PD history.