Patellofemoral instability in children: T2 relaxation times of the patellar cartilage in patients with and without patellofemoral instability and correlation with morphological grading of cartilage damage

Chang Ho Kang, Hee Kyung Kim, Sahar Shiraj, Christopher Anton, Dong Hoon Kim, Paul S. Horn

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

Background: Patellofemoral instability is one of the most common causes of cartilage damage in teenagers. Objective: To quantitatively evaluate the patellar cartilage in patients with patellofemoral instability using T2 relaxation time maps (T2 maps), compare the values to those in patients without patellofemoral instability and correlate them with morphological grades in patients with patellofemoral instability. Materials and methods: Fifty-three patients with patellofemoral instability (mean age: 15.9 ± 2.4 years) and 53 age- and gender-matched patients without patellofemoral instability were included. Knee MR with axial T2 map was performed. Mean T2 relaxation times were obtained at the medial, central and lateral zones of the patellar cartilage and compared between the two groups. In the patellofemoral instability group, morphological grading of the patellar cartilage (0-4) was performed and correlated with T2 relaxation times. Results: Mean T2 relaxation times were significantly longer in the group with patellofemoral instability as compared to those of the control group across the patellar cartilage (Student’s t-test, P<0.05) with the longest time at the central area. Positive correlation was seen between mean T2 relaxation time and morphological grading (Pearson correlation coefficiency, P<0.001). T2 increased with severity of morphological grading from 0 to 3 (mixed model, P<0.001), but no statistical difference was seen between grades 3 and 4. Conclusion: In patellofemoral instability, patellar cartilage damage occurs across the entire cartilage with the highest T2 values at the apex. T2 relaxation times directly reflect the severity in low-grade cartilage damage, which implies an important role for T2 maps in differentiating between normal and low-grade cartilage damage.

Original languageEnglish
Pages (from-to)1134-1141
Number of pages8
JournalPediatric Radiology
Volume46
Issue number8
DOIs
Publication statusPublished - 2016 Jul 1

Keywords

  • Cartilage
  • Children
  • Knee
  • Magnetic resonance imaging
  • Patellofemoral instability
  • Patellofemoral joint
  • T2 mapping

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health
  • Radiology Nuclear Medicine and imaging

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