Magnetic resonance imaging-based topographical differences between control and recurrent patellofemoral instability...

Area of Science:

• Orthopedic imaging
• Biomedical engineering
• Radiology

Background:

• Traditional imaging (plain films, CT) established patellar instability measurements.
• Limited research explored magnetic resonance imaging (MRI) for these evaluations.

Purpose of the Study:

• Identify morphological differences between normal knees and those with patellofemoral instability using MRI.
• Determine significant MRI measurements and compare them to historical radiographic/CT data.

Main Methods:

• Case-control study (Level 3 evidence) involving 81 controls and 40 patients with recurrent patellar instability.
• MRI analysis of patellar tilt, trochlear morphology, tibial tuberosity-trochlear groove (TTTG) distance, and patellar height.
• Evaluation of proximal and distal trochlear shape, including sulcus angle and lateral trochlear inclination.

Main Results:

• Significant differences found in all patellar tilt measurements between groups.
• Patella alta ratios (Insall-Salvati, Caton-Deschamps) were significantly different (P < 0.05).
• Numerous significant differences in proximal and distal trochlear morphology, including facet asymmetry, were observed.

Conclusions:

• MRI-based patellar tilt measurements effectively differentiate between normal knees and those with instability.
• Patella alta ratios and trochlear measurements show significant differences, confirming MRI's utility.
• MRI is appropriate for identifying pathological abnormalities associated with patellofemoral instability.