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Patellar Tendon-Trochlear Groove Angle Measurement: A New Method for Patellofemoral Rotational Analyses.

Hinckel BB, Gobbi RG, Kihara Filho EN, Demange MK, Pécora JR, Camanho GL - Orthop J Sports Med (2015)

Bottom Line: The measurements from the patellar instability and control groups, respectively, for angle 1 (16.4° and 8.4°), angle 2 (31° and 15.6°), angle 3 (30.8° and 15.7°), PT-TG distance (14.5 and 8.4 mm), and patellar tilt (21.1° and 7.5°) were significantly different (P < .05).The angle measurements showed greater sensitivity, specificity, and LR+ than the PT-TG distance.PT-TG angles are more closely associated with patellar instability than PT-TG distance.

View Article: PubMed Central - PubMed

Affiliation: Institute of Orthopedics and Traumatology of the Clinical Hospital, Medical School, University of São Paulo, São Paulo, Brazil.

ABSTRACT

Background: The tibial tubercle-trochlear groove (TT-TG) is used as the gold standard for patellofemoral malalignment.

Purpose: To assess 3 patellar tendon-trochlear groove (PT-TG) angle measurement techniques and the PT-TG distance measurement (tendinous cartilaginous TT-TG) as predictors of patellar instability.

Study design: Cohort study (diagnosis); Level of evidence, 3.

Methods: Three PT-TG angle measurements and the PT-TG distance were measured in 82 participants with patellar instability and 100 controls using magnetic resonance imaging (MRI). Measurement landmarks were the line tangent to the posterior femoral condyles, the deepest point of the trochlea, the transepicondylar line, and the patellar tendon center. All measurements were recorded once by 1 examiner, and the measurements were recorded twice by 2 examiners in a random group of 100 knees. Mean values and standard deviations (SDs) were obtained. Normality cutoff values were defined as 2 and 3 SDs above the mean in the control group. The sensitivity, specificity, and positive likelihood ratio (LR+) were calculated. Inter- and intrarater reliability were assessed based on the intraclass correlation coefficient (ICC).

Results: The measurements from the patellar instability and control groups, respectively, for angle 1 (16.4° and 8.4°), angle 2 (31° and 15.6°), angle 3 (30.8° and 15.7°), PT-TG distance (14.5 and 8.4 mm), and patellar tilt (21.1° and 7.5°) were significantly different (P < .05). The angle measurements showed greater sensitivity, specificity, and LR+ than the PT-TG distance. Inter- and intrarater ICC values were >0.95 for all measurements.

Conclusion: The PT-TG angle and the PT-TG distance are reliable and are different between the patellar instability and control groups. PT-TG angles are more closely associated with patellar instability than PT-TG distance.

Clinical relevance: PT-TG angle measurements show high reliability and association with patellar instability and can aid in the assessment of extensor mechanism malalignment. A more sensitive and specific evaluation of extensor mechanism malalignment can improve patient care by preventing both redislocation and abnormal tracking of overlooked malalignment and complications of unnecessary tibial tuberosity medialization.

No MeSH data available.


Related in: MedlinePlus

Patellar tendon–trochlear groove (PT-TG) central transepicondylar trochlear referenced angle in T2 fat suppression. (A) Trochlear axial cut: transepicondylar line and transepicondylar trochlear line. (B) Patellar tendon axial cut: transepicondylar line, transepicondylar trochlear line, patellar tendon center, and PT-TG angle 3.
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fig3-2325967115601031: Patellar tendon–trochlear groove (PT-TG) central transepicondylar trochlear referenced angle in T2 fat suppression. (A) Trochlear axial cut: transepicondylar line and transepicondylar trochlear line. (B) Patellar tendon axial cut: transepicondylar line, transepicondylar trochlear line, patellar tendon center, and PT-TG angle 3.

Mentions: On the trochlear axial cut, a line perpendicular to the transepicondylar line and another line perpendicular crossing the deepest point of the trochlear cartilage (transepicondylar trochlear line) were drawn and then transferred to the patellar tendon axial cut. The angle was formed by the transepicondylar trochlear line and the line between the intersection of the transepicondylar line with the transepicondylar trochlear line and the patellar tendon center (Figure 3).30


Patellar Tendon-Trochlear Groove Angle Measurement: A New Method for Patellofemoral Rotational Analyses.

Hinckel BB, Gobbi RG, Kihara Filho EN, Demange MK, Pécora JR, Camanho GL - Orthop J Sports Med (2015)

Patellar tendon–trochlear groove (PT-TG) central transepicondylar trochlear referenced angle in T2 fat suppression. (A) Trochlear axial cut: transepicondylar line and transepicondylar trochlear line. (B) Patellar tendon axial cut: transepicondylar line, transepicondylar trochlear line, patellar tendon center, and PT-TG angle 3.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License 1 - License 2 - License 3
Show All Figures
getmorefigures.php?uid=PMC4622295&req=5

fig3-2325967115601031: Patellar tendon–trochlear groove (PT-TG) central transepicondylar trochlear referenced angle in T2 fat suppression. (A) Trochlear axial cut: transepicondylar line and transepicondylar trochlear line. (B) Patellar tendon axial cut: transepicondylar line, transepicondylar trochlear line, patellar tendon center, and PT-TG angle 3.
Mentions: On the trochlear axial cut, a line perpendicular to the transepicondylar line and another line perpendicular crossing the deepest point of the trochlear cartilage (transepicondylar trochlear line) were drawn and then transferred to the patellar tendon axial cut. The angle was formed by the transepicondylar trochlear line and the line between the intersection of the transepicondylar line with the transepicondylar trochlear line and the patellar tendon center (Figure 3).30

Bottom Line: The measurements from the patellar instability and control groups, respectively, for angle 1 (16.4° and 8.4°), angle 2 (31° and 15.6°), angle 3 (30.8° and 15.7°), PT-TG distance (14.5 and 8.4 mm), and patellar tilt (21.1° and 7.5°) were significantly different (P < .05).The angle measurements showed greater sensitivity, specificity, and LR+ than the PT-TG distance.PT-TG angles are more closely associated with patellar instability than PT-TG distance.

View Article: PubMed Central - PubMed

Affiliation: Institute of Orthopedics and Traumatology of the Clinical Hospital, Medical School, University of São Paulo, São Paulo, Brazil.

ABSTRACT

Background: The tibial tubercle-trochlear groove (TT-TG) is used as the gold standard for patellofemoral malalignment.

Purpose: To assess 3 patellar tendon-trochlear groove (PT-TG) angle measurement techniques and the PT-TG distance measurement (tendinous cartilaginous TT-TG) as predictors of patellar instability.

Study design: Cohort study (diagnosis); Level of evidence, 3.

Methods: Three PT-TG angle measurements and the PT-TG distance were measured in 82 participants with patellar instability and 100 controls using magnetic resonance imaging (MRI). Measurement landmarks were the line tangent to the posterior femoral condyles, the deepest point of the trochlea, the transepicondylar line, and the patellar tendon center. All measurements were recorded once by 1 examiner, and the measurements were recorded twice by 2 examiners in a random group of 100 knees. Mean values and standard deviations (SDs) were obtained. Normality cutoff values were defined as 2 and 3 SDs above the mean in the control group. The sensitivity, specificity, and positive likelihood ratio (LR+) were calculated. Inter- and intrarater reliability were assessed based on the intraclass correlation coefficient (ICC).

Results: The measurements from the patellar instability and control groups, respectively, for angle 1 (16.4° and 8.4°), angle 2 (31° and 15.6°), angle 3 (30.8° and 15.7°), PT-TG distance (14.5 and 8.4 mm), and patellar tilt (21.1° and 7.5°) were significantly different (P < .05). The angle measurements showed greater sensitivity, specificity, and LR+ than the PT-TG distance. Inter- and intrarater ICC values were >0.95 for all measurements.

Conclusion: The PT-TG angle and the PT-TG distance are reliable and are different between the patellar instability and control groups. PT-TG angles are more closely associated with patellar instability than PT-TG distance.

Clinical relevance: PT-TG angle measurements show high reliability and association with patellar instability and can aid in the assessment of extensor mechanism malalignment. A more sensitive and specific evaluation of extensor mechanism malalignment can improve patient care by preventing both redislocation and abnormal tracking of overlooked malalignment and complications of unnecessary tibial tuberosity medialization.

No MeSH data available.


Related in: MedlinePlus