Summary
Objectives: To evaluate the repeatability and reproducibility of ultrasonographic fe-moral trochlear
depth measurements and to compare ultrasonographic and intra-operative evaluations
of femoral trochlear depth for predictive value in selecting trochleoplasty.
Methods: Repeatability and reproducibility of an ultrasonographic protocol were tested in
a preclinical cadaveric study. Clinical patients undergoing corrective surgery for
patellar luxation were evaluated preoperatively with ultrasound and intra-operatively
using a depth gauge. Measurements were assessed for equivalence using linear regression,
and agreement between decisions made based on these measurements assessed using Cohen’s
kappa.
Results: Although ultrasonographic and intra-operative measurements were in broad agreement,
the prediction interval was too wide for clinical use. There was no significant agreement
between predictions of the need for trochleoplasty using various cut-off values for
the two measurements, nor between these and the surgeon’s decision.
Clinical significance: Based on our observations, use of ultrasound for evaluation of the femoral trochlea
remains a largely qualitative assessment. A simpler and more direct objective measure
of femoral trochlear adequacy is required for intra-operative use.
Supplementary Material to this article is available online at https://doi.org/10.3415/VCOT-16-06-0084
Keywords
Patellar luxation - ultrasound - trochleoplasty - agreement - repeatability
