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Spectrum of injuries associated with paediatric ACL tears: an MRI pictorial review.

Jaremko JL, Guenther ZD, Jans LB, Macmahon PJ - Insights Imaging (2013)

Bottom Line: ACL injury usually occurs with axial rotation in the valgus near full extension.Paediatric-specific issues of note include tibial spine avulsion, normal difficulty visualising a thin ACL and posterolateral corner structures, and differentiation between incompletely closed physis and impaction fracture.Awareness of the spectrum of secondary findings illustrated here and the features distinguishing them from normal variation can aid in accurate assessment of ACL tears and related injuries, enabling effective treatment planning and assessment of prognosis. • The ACL in children normally appears thin or attenuated, while thickening and oedema suggest tear. • Displaced medial meniscal tears are significantly more common later post-injury than immediately. • The meniscofemoral ligaments merge with the posterior lateral meniscus, complicating tear assessment. • Tibial plateau impaction fractures can be difficult to distinguish from a partially closed physis. • Axial MR sequences are more sensitive/specific than coronal for diagnosis of medial collateral ligament (MCL) injury.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology and Diagnostic Imaging, 2A2.42 Walter Mackenzie Health Sciences Centre, University of Alberta, Edmonton, Alberta, Canada, T6G 2B7, jjaremko@ualberta.ca.

ABSTRACT

Objective: Magnetic resonance imaging (MRI) findings in anterior cruciate ligament (ACL) injury are well known, but most published reviews show obvious examples of associated injuries and give little focus to paediatric patients. Here, we demonstrate the spectrum of MRI appearances at common sites of associated injury in adolescents with ACL tears, emphasising age-specific issues.

Methods: Pictorial review using images from children with surgically confirmed ACL tears after athletic injury.

Results: ACL injury usually occurs with axial rotation in the valgus near full extension. The MRI findings can be obvious and important to management (ACL rupture), subtle but clinically important (lateral meniscus posterior attachment avulsion), obvious and unimportant to management (femoral condyle impaction injury), or subtle and possibly important (medial meniscocapsular junction tear). Paediatric-specific issues of note include tibial spine avulsion, normal difficulty visualising a thin ACL and posterolateral corner structures, and differentiation between incompletely closed physis and impaction fracture.

Conclusion: ACL tear is only the most obvious sign of a complex injury involving multiple structures. Awareness of the spectrum of secondary findings illustrated here and the features distinguishing them from normal variation can aid in accurate assessment of ACL tears and related injuries, enabling effective treatment planning and assessment of prognosis.

Teaching points: • The ACL in children normally appears thin or attenuated, while thickening and oedema suggest tear. • Displaced medial meniscal tears are significantly more common later post-injury than immediately. • The meniscofemoral ligaments merge with the posterior lateral meniscus, complicating tear assessment. • Tibial plateau impaction fractures can be difficult to distinguish from a partially closed physis. • Axial MR sequences are more sensitive/specific than coronal for diagnosis of medial collateral ligament (MCL) injury.

No MeSH data available.


Related in: MedlinePlus

Posterolateral corner on sagittal PD FS images. a Normal, with intact lateral meniscus, and superior and inferior popliteomeniscal struts (arrows). b Tear of the superior (arrow) and inferior popliteomeniscal struts, with intact meniscus but associated tibial and femoral marrow contusions. c Vertical tear of lateral meniscus (arrow), with irregular appearance of inferior popliteomeniscal strut suggesting incomplete tearing, marrow contusions similar in pattern to b, and a partly visualised lateral femoral condyle impaction fracture
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Fig6: Posterolateral corner on sagittal PD FS images. a Normal, with intact lateral meniscus, and superior and inferior popliteomeniscal struts (arrows). b Tear of the superior (arrow) and inferior popliteomeniscal struts, with intact meniscus but associated tibial and femoral marrow contusions. c Vertical tear of lateral meniscus (arrow), with irregular appearance of inferior popliteomeniscal strut suggesting incomplete tearing, marrow contusions similar in pattern to b, and a partly visualised lateral femoral condyle impaction fracture

Mentions: The posterolateral corner is an often overlooked site of soft tissue injury in patients with ACL tears. Injuries most commonly involve the popliteomeniscal fascicles (Fig. 6a, b), and the adjacent lateral meniscus (Fig. 6c) [23]. The popliteomeniscal fascicles are meniscocapsular extensions that blend with the popliteus and are considered functionally important stabilisers of the lateral meniscus, working in conjunction with the popliteus to prevent excessive lateral meniscal movement [24]. In adults, posterolateral corner injury implies a higher risk of ACL graft failure, likely due to the associated increased rotational instability [25]. This is likely also true in children but is not as well documented. Unfortunately, particularly in children these tiny structures are poorly seen, especially with motion artefact or a relatively large MRI field of view. The combination of regional oedema and non-visualisation of these tiny structures suggests, but does not confirm, a posterolateral corner injury. An abnormal superior popliteomeniscal fascicle serves as a useful clue for the detection of subtle lateral meniscal abnormalities and has been shown to be highly associated with a tear of the lateral meniscus, with reported positive predictive value 79 % and specificity 96 % [26].Fig. 6


Spectrum of injuries associated with paediatric ACL tears: an MRI pictorial review.

Jaremko JL, Guenther ZD, Jans LB, Macmahon PJ - Insights Imaging (2013)

Posterolateral corner on sagittal PD FS images. a Normal, with intact lateral meniscus, and superior and inferior popliteomeniscal struts (arrows). b Tear of the superior (arrow) and inferior popliteomeniscal struts, with intact meniscus but associated tibial and femoral marrow contusions. c Vertical tear of lateral meniscus (arrow), with irregular appearance of inferior popliteomeniscal strut suggesting incomplete tearing, marrow contusions similar in pattern to b, and a partly visualised lateral femoral condyle impaction fracture
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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Fig6: Posterolateral corner on sagittal PD FS images. a Normal, with intact lateral meniscus, and superior and inferior popliteomeniscal struts (arrows). b Tear of the superior (arrow) and inferior popliteomeniscal struts, with intact meniscus but associated tibial and femoral marrow contusions. c Vertical tear of lateral meniscus (arrow), with irregular appearance of inferior popliteomeniscal strut suggesting incomplete tearing, marrow contusions similar in pattern to b, and a partly visualised lateral femoral condyle impaction fracture
Mentions: The posterolateral corner is an often overlooked site of soft tissue injury in patients with ACL tears. Injuries most commonly involve the popliteomeniscal fascicles (Fig. 6a, b), and the adjacent lateral meniscus (Fig. 6c) [23]. The popliteomeniscal fascicles are meniscocapsular extensions that blend with the popliteus and are considered functionally important stabilisers of the lateral meniscus, working in conjunction with the popliteus to prevent excessive lateral meniscal movement [24]. In adults, posterolateral corner injury implies a higher risk of ACL graft failure, likely due to the associated increased rotational instability [25]. This is likely also true in children but is not as well documented. Unfortunately, particularly in children these tiny structures are poorly seen, especially with motion artefact or a relatively large MRI field of view. The combination of regional oedema and non-visualisation of these tiny structures suggests, but does not confirm, a posterolateral corner injury. An abnormal superior popliteomeniscal fascicle serves as a useful clue for the detection of subtle lateral meniscal abnormalities and has been shown to be highly associated with a tear of the lateral meniscus, with reported positive predictive value 79 % and specificity 96 % [26].Fig. 6

Bottom Line: ACL injury usually occurs with axial rotation in the valgus near full extension.Paediatric-specific issues of note include tibial spine avulsion, normal difficulty visualising a thin ACL and posterolateral corner structures, and differentiation between incompletely closed physis and impaction fracture.Awareness of the spectrum of secondary findings illustrated here and the features distinguishing them from normal variation can aid in accurate assessment of ACL tears and related injuries, enabling effective treatment planning and assessment of prognosis. • The ACL in children normally appears thin or attenuated, while thickening and oedema suggest tear. • Displaced medial meniscal tears are significantly more common later post-injury than immediately. • The meniscofemoral ligaments merge with the posterior lateral meniscus, complicating tear assessment. • Tibial plateau impaction fractures can be difficult to distinguish from a partially closed physis. • Axial MR sequences are more sensitive/specific than coronal for diagnosis of medial collateral ligament (MCL) injury.

View Article: PubMed Central - PubMed

Affiliation: Department of Radiology and Diagnostic Imaging, 2A2.42 Walter Mackenzie Health Sciences Centre, University of Alberta, Edmonton, Alberta, Canada, T6G 2B7, jjaremko@ualberta.ca.

ABSTRACT

Objective: Magnetic resonance imaging (MRI) findings in anterior cruciate ligament (ACL) injury are well known, but most published reviews show obvious examples of associated injuries and give little focus to paediatric patients. Here, we demonstrate the spectrum of MRI appearances at common sites of associated injury in adolescents with ACL tears, emphasising age-specific issues.

Methods: Pictorial review using images from children with surgically confirmed ACL tears after athletic injury.

Results: ACL injury usually occurs with axial rotation in the valgus near full extension. The MRI findings can be obvious and important to management (ACL rupture), subtle but clinically important (lateral meniscus posterior attachment avulsion), obvious and unimportant to management (femoral condyle impaction injury), or subtle and possibly important (medial meniscocapsular junction tear). Paediatric-specific issues of note include tibial spine avulsion, normal difficulty visualising a thin ACL and posterolateral corner structures, and differentiation between incompletely closed physis and impaction fracture.

Conclusion: ACL tear is only the most obvious sign of a complex injury involving multiple structures. Awareness of the spectrum of secondary findings illustrated here and the features distinguishing them from normal variation can aid in accurate assessment of ACL tears and related injuries, enabling effective treatment planning and assessment of prognosis.

Teaching points: • The ACL in children normally appears thin or attenuated, while thickening and oedema suggest tear. • Displaced medial meniscal tears are significantly more common later post-injury than immediately. • The meniscofemoral ligaments merge with the posterior lateral meniscus, complicating tear assessment. • Tibial plateau impaction fractures can be difficult to distinguish from a partially closed physis. • Axial MR sequences are more sensitive/specific than coronal for diagnosis of medial collateral ligament (MCL) injury.

No MeSH data available.


Related in: MedlinePlus