Ultrasound Measurement of Lateral Patellar Displacement: A Cadaveric Validation Study.
Lok Yin Ada Kwan, Alban Killingback, Philip J Adds
PMID 36237660WHAT IT FOUND
Ultrasound measurements of patellar position matched direct surgical measurements in cadavers, with a strong correlation between the two methods.
This validates ultrasound as a tool for assessing lateral patellar displacement, though confirmation in living patients with knee pain is still required.
Key findings
01Ultrasound measurements of the distance between the patella and femoral condyle showed a strong correlation with direct surgical measurements in both neutral and adducted hip positions.
02There was no statistically significant difference between the results obtained by ultrasound and those obtained by direct measurement.
03The intra-rater reliability for both ultrasound and direct measurement techniques was high, with coefficient of variation values below 5%.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
The study used cadavers with a mean age of 82.4 years, so the tissue properties and potential presence of osteoarthritis may not represent a younger, symptomatic patient population. Measurements were taken in a non-weight-bearing, passive position, which differs from the dynamic, weight-bearing conditions of most clinical assessments. The sample size was small (9 cadavers), and most subjects were female (8 out of 9), which may limit generalizability. Medical records were unavailable, so undetected pathology in the donor knees or hips could have influenced the results.
Declared interests
The authors declared no conflicts of interest. The study was internally funded by St George’s, University of London.
The easy way to misread this
Do not assume this validates ultrasound for assessing patellar tracking in living patients during functional movements like squatting or walking. The study only validated static, non-weight-bearing measurements in cadaveric tissue, which behaves differently than living muscle and joint structures.