Quality assessment of radiological measurements of trochlear dysplasia; a literature review

Background:The clinical impact of increased torsion on patellar instability and patellofemoral pain syndrome (PFPS) has been suggested by several studies.Hypothesis:The hypotheses of this study were that (1) torsional malalignment (TM) is characterized by a positive correlation between different malalignment parameters that represent an overall picture of the malalignment syndrome and (2) an increase in overall torsion is the underlying difference between patellar instability and isolated patellofemoral pain.Study Design:Cohort study; Level of evidence, 3.Methods:Between April 2015 and July 2017, a total of 428 patients were treated for lateral patellar dislocation (LPD), and 333 patients were treated for PFPS. Sixty-two patients (14.5%) with patellar instability (LPD group) and 29 patients (8.7%) with patellofemoral pain (PFPS group) had additional TM and were included in this study. All patients underwent magnetic resonance imaging for torsional alignment and patellar tracking, including femoral antetorsion, tibial torsion, knee rotation, tibial tuberosity–trochlear groove (TT-TG) distance, tibial tuberosity–posterior cruciate ligament (TT-PCL) distance, Dejour classification of trochlear dysplasia, lateral trochlear inclination (LTI) angle, and patellar height.Results:The LPD and PFPS groups differed significantly in terms of trochlear dysplasia (P < .001), LTI angle (P < .001), and TT-TG distance (P = .0167) but did not differ in terms of femoral antetorsion (20.02° ± 8.80° vs 20.03° ± 7.91°, respectively; P = .8545), tibial torsion (39.53° ± 9.23° vs 41.24° ± 7.28°, respectively; P = .3616), or knee rotation (10.42° ± 5.16° vs 8.48° ± 7.81°, respectively; P = .0163). Only measures of TT-TG distance and TT-PCL distance and measures of TT-TG distance and knee rotation were positively correlated. Trochlear dysplasia (type B-D) was identified as the only significant predictor of patellar instability.Conclusion:TM in patients with either PFPS or LPD does not appear to be characterized by a fixed constellation of different malalignment parameters. Between groups, the parameters differed significantly only in terms of trochlear dysplasia and the TT-TG distance, and trochlear dysplasia (type B-D) (but not torsion) was identified as a predictor of lateral patellar instability.

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“…Eight established parameters of limb alignment and patellar tracking were assessed as previously published. 7,9,12,17,21,28–30…”

Section: Methodsmentioning

confidence: 99%

“…Using a diagnostic threshold of 11°, this measure has shown a sensitivity of 93% and a specificity of 87% for trochlear dysplasia 6 and is recommended for use in the assessment of trochlear dysplasia. 28…”

Section: Methodsmentioning

confidence: 99%

Geometry of Torsional Malalignment Syndrome: Trochlear Dysplasia but Not Torsion Predicts Lateral Patellar Instability

Balcarek

Radebold

Schulz

et al. 2019

Orthopaedic Journal of Sports Medicine

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“… 6 , 27 , 31 Because the LTI is an MRI measurement, it better characterizes the proximal trochlea, which is an area difficult to appreciate on conventional radiographs as is attempted using the Dejour radiographic classification. 5 , 23 , 25 , 32 Also, LTI provides a quantitative description of dysplasia. Carrillon et al 5 reported that an LTI of < 11° is associated with a 95% specificity of having PI secondary to TD.…”

mentioning

confidence: 99%

Lateral Trochlear Inclination Angle: Measurement via a 2-Image Technique to Reliably Characterize and Quantify Trochlear Dysplasia

Joseph

Cheng

Solomito

et al. 2020

Orthopaedic Journal of Sports Medicine

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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.

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“…The distance from this line to the deepest part of the trochlea was determined in a similar way to the trochlear depth. [10] The trochlear facet asymmetry was determined by measuring the medial (MT) and lateral (LT) trochlea facet lengths 30 mm above the axial cross-section of the articular line and proportioned to each other. [11] The lateral trochlear inclinations (LTI) were determined by measuring the angle between the posterior femoral condyles and the lateral facet with the Cobb method in the most superior axial MR section.…”

Section: Radiographic Assessment and Reliability Of Measurementsmentioning

confidence: 99%

“…[11] The sulcus angle was determined on the axial MR sequence at the level of the deepest depression of the intercondylar groove by measuring the angle between the ventral articular surfaces of the medial and lateral condyle. [10] The patellar tilt angle (PTA) was determined by drawing a line along the lateral joint surface of the patella and a line drawn along the posterior condylar line using the Cobb method feature of the picture archiving and communication system (PACS) program. [12] Medial plicae thickness was measured on the axial MRI images by using the magnifying feature of the program.…”

Section: Radiographic Assessment and Reliability Of Measurementsmentioning

confidence: 99%

Association between patellofemoral congruence and patellofemoral chondropathy in patients with anterior knee pain: A T2 mapping knee MRI study

Türkmen

Işık²

2018

Eklem Hastalik Cerrahisi

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Based on our study findings, the T2 mapping magnetic resonance imaging (MRI) technique was found to be reliable test that can be used to diagnose early cartilage damage in patients with anterior knee pain. In patients with anterior knee pain, especially with decreased Insall Salvatti index, low lateral trochlear inclination angle, and higher patellar tilt angle, adding a T2 mapping sequence to the standard knee MRI protocol is recommended to help detect early cartilage damage.

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Quality assessment of radiological measurements of trochlear dysplasia; a literature review

Abstract: V.

Cited by 83 publications

References 24 publications

Geometry of Torsional Malalignment Syndrome: Trochlear Dysplasia but Not Torsion Predicts Lateral Patellar Instability

Geometry of Torsional Malalignment Syndrome: Trochlear Dysplasia but Not Torsion Predicts Lateral Patellar Instability

Lateral Trochlear Inclination Angle: Measurement via a 2-Image Technique to Reliably Characterize and Quantify Trochlear Dysplasia

Association between patellofemoral congruence and patellofemoral chondropathy in patients with anterior knee pain: A T2 mapping knee MRI study

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