Extreme trochlear morphology in pediatric patients with fixed lateral patellar dislocation: a radiographic study

Area of Science:

• Orthopedic surgery
• Pediatric orthopedics
• Radiology

Background:

• Fixed lateral patellar dislocations (FLPD) are a rare chronic patellofemoral instability (PFI) subtype.
• Understanding FLPD's unique radiographic morphology is crucial for effective management.

Purpose of the Study:

• To describe radiographic morphological features in pediatric FLPD patients.
• To compare these features against acute patellar dislocation (APD) and unaffected controls.

Main Methods:

• Retrospective review of pediatric patients undergoing MPFL reconstruction for FLPD or APD.
• Age- and sex-matched controls without PFI were included.
• Analysis of MRI scans for bony sulcus angle (BSA), cartilaginous sulcus angle (CSA), patellar tilt, trochlear depth, patellar lateralization, and TT-TG distance.

Main Results:

• FLPD group exhibited significantly greater BSA, CSA, lateral patellar inclination, patellar lateralization, and TT-TG compared to controls and APD groups (p < 0.001).
• The FLPD group demonstrated reduced trochlear depth (2.76 mm less) versus controls (p < 0.001).
• Ten FLPD patients had associated syndromic or congenital conditions.

Conclusions:

• Pediatric FLPD patients present with more severe patellofemoral abnormalities than APD patients and controls.
• Findings suggest absent patellar contact contributes to progressive trochlear flattening.
• Surgical intervention is supported to enhance function and quality of life in FLPD.