Speaker: MRI may not reliably measure medial, lateral posterior tibial slope
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Key takeaways:
- Measurements of posterior tibial slope at the medial and lateral plateaus may not be reliable on traditional MRI.
- MRI measurements demonstrated high variability and minimal bias compared with CT measurements.
WASHINGTON — Measurements of medial and lateral posterior tibial slope on MRI demonstrated lower interrater reliability compared with measurements on CT and may not be accurate, according to presented results.
“The diagnostic workup of patients with ACL injury typically includes MRI but not CT, although CT is the gold standard for evaluating the osseous geometry,” Deborah Wen, BS, said in her presentation at the American Orthopaedic Society for Sports Medicine Annual Meeting. “It is currently unknown whether or not traditional MRI can be used to accurately measure [posterior tibial slope] at the medial and lateral plateaus and how MRI measurements might correlate to those on CT,” she added.
Wen and colleagues retrospectively analyzed data on 41 knees from 40 patients (mean age of 37.9 years) who received concurrent MRI and CT imaging of the same knee within 1 year. Researchers examined interrater reliability of posterior tibial slope measurements at the medial tibial plateau and lateral tibial plateau and inter-method agreement between MRI and CT measurements.
Overall, mean absolute differences in posterior tibial slope measurements between MRI and CT were 2.6° at both the medial tibial plateau and lateral tibial plateau . According to the abstract, mean posterior tibial slope measurements at the medial tibial plateau were 3.3° on MRI and 3.7° on CT, while mean posterior tibial slope measurements at the lateral tibial plateau were 4.5° on MRI and 5.2° on CT.
Wen noted poor inter-method agreement between MRI and CT at the medial tibial plateau and moderate inter-method agreement between MRI and CT at the lateral tibial plateau . Additionally, she noted posterior tibial slope measurements on MRI demonstrated lower interrater reliability with high variability and minimal bias compared with posterior tibial slope measurements on CT.
Wen concluded that measurements of posterior tibial slope at the medial and lateral plateaus may not be reliable on traditional MRI.
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Wen D, et al. Paper 24. Presented at: American Orthopaedic Society for Sports Medicine Annual Meeting; July 12-16, 2023; Washington, D.C.
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