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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

Spectrum of posteromedial corner injury on sagittal T2 FS images (image d is T2 GRE). a Intact meniscus: normal (left); increased signal at meniscocapsular junction representing minor strain, not meeting criteria for tear (middle; note the underlying tibial contusion); meniscocapsular junction tear, with no dark meniscal tissue posterior to the high-signal cleft (right). b Meniscal tears: horizontal extending to undersurface (left); oblique tear with tibial contusion (middle); displaced oblique tear with tibial contusion (right). c Meniscal tears: vertical tear (left); vertical and intrasubstance tear (middle); displaced complex tear, with vertical and horizontal components (right)
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Fig4: Spectrum of posteromedial corner injury on sagittal T2 FS images (image d is T2 GRE). a Intact meniscus: normal (left); increased signal at meniscocapsular junction representing minor strain, not meeting criteria for tear (middle; note the underlying tibial contusion); meniscocapsular junction tear, with no dark meniscal tissue posterior to the high-signal cleft (right). b Meniscal tears: horizontal extending to undersurface (left); oblique tear with tibial contusion (middle); displaced oblique tear with tibial contusion (right). c Meniscal tears: vertical tear (left); vertical and intrasubstance tear (middle); displaced complex tear, with vertical and horizontal components (right)

Mentions: This region is the site of frequent, generally minor injury, either involving the meniscocapsular junction (Fig. 4b, c) or the peripheral “red” portion of the meniscus (Fig. 4d–i). The capsule posterior to the medial meniscus is usually only slightly higher in signal than adjacent tissue (Fig. 4a). In the posteromedial knee there is a confluence of structures (posterior oblique ligament, oblique popliteal ligament, and fibres of the semimembranosus tendon) that reinforce the posteromedial joint capsule. With valgus stress and knee rotation, capsular tension is transmitted to the meniscocapsular junction which places tensile stress on the periphery of the meniscus which can be subsequently torn [19]. The orientation (peripheral, vertical, and longitudinal) of this medial meniscal tear is typical after sports-related trauma. These tears account for most of the “false-positive” MRI diagnoses of meniscal tears, based on their absence (or interval healing) at later arthroscopy [20]. A likely explanation is that since the periphery of the meniscus is well vascularised, these tears heal well in the interval between MRI and surgery.Fig. 4


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

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

Spectrum of posteromedial corner injury on sagittal T2 FS images (image d is T2 GRE). a Intact meniscus: normal (left); increased signal at meniscocapsular junction representing minor strain, not meeting criteria for tear (middle; note the underlying tibial contusion); meniscocapsular junction tear, with no dark meniscal tissue posterior to the high-signal cleft (right). b Meniscal tears: horizontal extending to undersurface (left); oblique tear with tibial contusion (middle); displaced oblique tear with tibial contusion (right). c Meniscal tears: vertical tear (left); vertical and intrasubstance tear (middle); displaced complex tear, with vertical and horizontal components (right)
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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Fig4: Spectrum of posteromedial corner injury on sagittal T2 FS images (image d is T2 GRE). a Intact meniscus: normal (left); increased signal at meniscocapsular junction representing minor strain, not meeting criteria for tear (middle; note the underlying tibial contusion); meniscocapsular junction tear, with no dark meniscal tissue posterior to the high-signal cleft (right). b Meniscal tears: horizontal extending to undersurface (left); oblique tear with tibial contusion (middle); displaced oblique tear with tibial contusion (right). c Meniscal tears: vertical tear (left); vertical and intrasubstance tear (middle); displaced complex tear, with vertical and horizontal components (right)
Mentions: This region is the site of frequent, generally minor injury, either involving the meniscocapsular junction (Fig. 4b, c) or the peripheral “red” portion of the meniscus (Fig. 4d–i). The capsule posterior to the medial meniscus is usually only slightly higher in signal than adjacent tissue (Fig. 4a). In the posteromedial knee there is a confluence of structures (posterior oblique ligament, oblique popliteal ligament, and fibres of the semimembranosus tendon) that reinforce the posteromedial joint capsule. With valgus stress and knee rotation, capsular tension is transmitted to the meniscocapsular junction which places tensile stress on the periphery of the meniscus which can be subsequently torn [19]. The orientation (peripheral, vertical, and longitudinal) of this medial meniscal tear is typical after sports-related trauma. These tears account for most of the “false-positive” MRI diagnoses of meniscal tears, based on their absence (or interval healing) at later arthroscopy [20]. A likely explanation is that since the periphery of the meniscus is well vascularised, these tears heal well in the interval between MRI and surgery.Fig. 4

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