Patellar tilt: the physical examination correlates with MR imaging

Area of Science:

• Orthopedics
• Radiology
• Biomedical Engineering

Background:

• Patellar tilt is a common form of patella malalignment, frequently causing knee pain.
• Existing methods for assessing patellar tilt include physical examination and computerized imaging, but their correlation is not well-established.
• A reliable correlation would enhance the diagnostic value of both clinical and imaging assessments, especially in cases where physical examination is challenging (e.g., obesity).

Purpose of the Study:

• To establish the correlation between physical examination findings of patellar tilt and magnetic resonance (MR) imaging measurements.
• To introduce and validate a novel, intuitive MRI Tilt Angle for quantifying patellar tilt.
• To provide an objective imaging substitute for clinical assessment of patellar tilt.

Main Methods:

• A new MRI Tilt Angle was developed, measured similarly to physical examination techniques but referenced off the posterior femoral condyles.
• Unlike some existing methods, this MRI Tilt Angle increases intuitively with increasing patellar tilt.
• The study involved examining 30 patients with diagnosed patellar tilt and 51 patients without tilt.

Main Results:

• A strong correlation was observed between physical examination findings and the novel MRI Tilt Angle.
• An MRI Tilt Angle of 10 degrees or greater reliably indicates significant patellar tilt on physical examination.
• An MRI Tilt Angle below 10 degrees is associated with the absence of significant patellar tilt.

Conclusions:

• The developed MRI Tilt Angle provides an easy, objective, and intuitive method for measuring patellar tilt.
• This imaging measurement serves as an excellent adjunct to the physical examination for diagnosing patellar tilt.
• The MRI Tilt Angle can be a valuable tool for assessing patellar malalignment, particularly when clinical assessment is limited.