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Lateral Trochlear Inclination Angle: Measurement via a 2-Image Technique to Reliably Characterize and Quantify Trochlear Dysplasia
BACKGROUND: Trochlear dysplasia (TD) is a risk factor for patellar instability (PI). The Dejour classification categorizes TD but has suboptimal reliability. Lateral trochlear inclination (LTI) is a quantitative measurement of trochlear dysplasia on a single axial magnetic resonance imaging (MRI) sc...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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SAGE Publications
2020
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7551490/ https://www.ncbi.nlm.nih.gov/pubmed/33102608 http://dx.doi.org/10.1177/2325967120958415 |
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author | Joseph, Sheeba M. Cheng, Chris Solomito, Matthew J. Pace, J. Lee |
author_facet | Joseph, Sheeba M. Cheng, Chris Solomito, Matthew J. Pace, J. Lee |
author_sort | Joseph, Sheeba M. |
collection | PubMed |
description | BACKGROUND: Trochlear dysplasia (TD) is a risk factor for patellar instability (PI). The Dejour classification categorizes TD but has suboptimal reliability. Lateral trochlear inclination (LTI) is a quantitative measurement of trochlear dysplasia on a single axial magnetic resonance imaging (MRI) scan. HYPOTHESIS: A modified LTI measurement technique using 2 different axial MRI scans that reference the most proximal aspect of the trochlear cartilage on 1 image and the fully formed posterior condyles on the second image would be as reliable as and significantly different from the single-image measurement technique for LTI. Further, the 2-image LTI would adequately represent overall proximal trochlear morphologic characteristics. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 2. METHODS: Patients aged 9 to 18 years treated for PI between 2014 and 2017 were identified. The Dejour classification was radiographically determined. Single-image LTI was measured on a single axial MRI scan at the most proximal aspect of visible trochlear cartilage. A 2-image LTI was measured from 2 separate MRI scans: 1 at the most proximal aspect of trochlear cartilage and the second at the fully formed posterior condyles. This 2-image LTI was repeated at 3 subsequent levels (the first measurement is referred to as LTI-1; repeated measurements are LTI-2, LTI-3, and LTI-4, moving distally). In total, 65 patients met the inclusion criteria, and 30 were randomly selected for reliability analysis. RESULTS: Inter- and intrarater reliability trended toward more variability for single-image LTI (intraclass correlation coefficient [ICC], 0.86 and 0.88, respectively) than for 2-image LTI (ICC, 0.97 and 0.96, respectively). The Dejour classification had lower intra- and interrater reliability (ICC, 0.31 and 0.73, respectively). Average single-image LTI (9.2° ± 12.6°) was greater than average 2-image LTI-1 (4.2° SD ± 11.9°) (P = .0125). Single-image LTI classified 60% of patients with PI as having TD, whereas the 2-image LTI classified 71% as having TD. The 2-image LTI was able to capture 91% of overall proximal trochlear morphologic characteristics. CONCLUSION: LTI has higher reliability when performed using a 2-image measurement technique compared with single-image LTI and Dejour classification. The strong correlation between 2-image LTI and average LTI shows that 91% of TD is represented on the most proximal axial image. Because the single-image measurement appears to underestimate dysplasia, previously described thresholds should be reexamined using this 2-image technique to appropriately characterize TD. |
format | Online Article Text |
id | pubmed-7551490 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
publisher | SAGE Publications |
record_format | MEDLINE/PubMed |
spelling | pubmed-75514902020-10-23 Lateral Trochlear Inclination Angle: Measurement via a 2-Image Technique to Reliably Characterize and Quantify Trochlear Dysplasia Joseph, Sheeba M. Cheng, Chris Solomito, Matthew J. Pace, J. Lee Orthop J Sports Med Article BACKGROUND: Trochlear dysplasia (TD) is a risk factor for patellar instability (PI). The Dejour classification categorizes TD but has suboptimal reliability. Lateral trochlear inclination (LTI) is a quantitative measurement of trochlear dysplasia on a single axial magnetic resonance imaging (MRI) scan. HYPOTHESIS: A modified LTI measurement technique using 2 different axial MRI scans that reference the most proximal aspect of the trochlear cartilage on 1 image and the fully formed posterior condyles on the second image would be as reliable as and significantly different from the single-image measurement technique for LTI. Further, the 2-image LTI would adequately represent overall proximal trochlear morphologic characteristics. STUDY DESIGN: Cohort study (diagnosis); Level of evidence, 2. METHODS: Patients aged 9 to 18 years treated for PI between 2014 and 2017 were identified. The Dejour classification was radiographically determined. Single-image LTI was measured on a single axial MRI scan at the most proximal aspect of visible trochlear cartilage. A 2-image LTI was measured from 2 separate MRI scans: 1 at the most proximal aspect of trochlear cartilage and the second at the fully formed posterior condyles. This 2-image LTI was repeated at 3 subsequent levels (the first measurement is referred to as LTI-1; repeated measurements are LTI-2, LTI-3, and LTI-4, moving distally). In total, 65 patients met the inclusion criteria, and 30 were randomly selected for reliability analysis. RESULTS: Inter- and intrarater reliability trended toward more variability for single-image LTI (intraclass correlation coefficient [ICC], 0.86 and 0.88, respectively) than for 2-image LTI (ICC, 0.97 and 0.96, respectively). The Dejour classification had lower intra- and interrater reliability (ICC, 0.31 and 0.73, respectively). Average single-image LTI (9.2° ± 12.6°) was greater than average 2-image LTI-1 (4.2° SD ± 11.9°) (P = .0125). Single-image LTI classified 60% of patients with PI as having TD, whereas the 2-image LTI classified 71% as having TD. The 2-image LTI was able to capture 91% of overall proximal trochlear morphologic characteristics. CONCLUSION: LTI has higher reliability when performed using a 2-image measurement technique compared with single-image LTI and Dejour classification. The strong correlation between 2-image LTI and average LTI shows that 91% of TD is represented on the most proximal axial image. Because the single-image measurement appears to underestimate dysplasia, previously described thresholds should be reexamined using this 2-image technique to appropriately characterize TD. SAGE Publications 2020-10-08 /pmc/articles/PMC7551490/ /pubmed/33102608 http://dx.doi.org/10.1177/2325967120958415 Text en © The Author(s) 2020 https://creativecommons.org/licenses/by-nc-nd/4.0/ This article is distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 License (https://creativecommons.org/licenses/by-nc-nd/4.0/) which permits non-commercial use, reproduction and distribution of the work as published without adaptation or alteration, without further permission provided the original work is attributed as specified on the SAGE and Open Access pages (https://us.sagepub.com/en-us/nam/open-access-at-sage). |
spellingShingle | Article Joseph, Sheeba M. Cheng, Chris Solomito, Matthew J. Pace, J. Lee Lateral Trochlear Inclination Angle: Measurement via a 2-Image Technique to Reliably Characterize and Quantify Trochlear Dysplasia |
title | Lateral Trochlear Inclination Angle: Measurement via a 2-Image
Technique to Reliably Characterize and Quantify Trochlear
Dysplasia |
title_full | Lateral Trochlear Inclination Angle: Measurement via a 2-Image
Technique to Reliably Characterize and Quantify Trochlear
Dysplasia |
title_fullStr | Lateral Trochlear Inclination Angle: Measurement via a 2-Image
Technique to Reliably Characterize and Quantify Trochlear
Dysplasia |
title_full_unstemmed | Lateral Trochlear Inclination Angle: Measurement via a 2-Image
Technique to Reliably Characterize and Quantify Trochlear
Dysplasia |
title_short | Lateral Trochlear Inclination Angle: Measurement via a 2-Image
Technique to Reliably Characterize and Quantify Trochlear
Dysplasia |
title_sort | lateral trochlear inclination angle: measurement via a 2-image
technique to reliably characterize and quantify trochlear
dysplasia |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7551490/ https://www.ncbi.nlm.nih.gov/pubmed/33102608 http://dx.doi.org/10.1177/2325967120958415 |
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