A Case Report on the Hidden Lesion of the Knee: Ramp Lesion

Abstract

Introduction
Ramp lesions, often associated with anterior cruciate ligament (ACL) injuries, exhibit a varied incidence rate of 9–42%, increasing with delayed ACL reconstruction. These lesions, resulting from abnormal tibial movements and semimembranosus muscle contraction, are challenging to diagnose due to their hidden nature in standard magnetic resonance imaging and arthroscopy procedures.

Case Report
This report examines the case of a ramp lesion in the context of a multi-ligament injured knee of a 34-year-old male. The patient had a complete ACL, medial collateral ligament, and avulsion of the posterior cruciate ligament with a type 1 ramp lesion. These findings were confirmed by arthroscopy and were treated with arthroscopic reconstruction of the ligament and all inside repair of the ramp lesion. We report the pertinent imaging findings relevant to the ramp lesions.

Conclusion
Ramp lesions present a significant diagnostic and treatment challenge in orthopedic practice. Enhanced imaging techniques and a deeper understanding of their pathophysiology are crucial for an accurate diagnosis.

Full text

Introduction
The posteromedial knee ramp lesions, likened to ramps for their
shape, have been known since 1983 but have gained recent
attention due to their association with ACL injuries. These
lesions, first termed “Ramp lesions” by Michael J. Strobel, involve
the peripheral attachment of the posterior horn of the medial
meniscus. For years, these injuries were often overlooked in
magnetic resonance imaging (MRIs) and ar throscopies,
primarily because standard MRI procedures, conducted with the
knee fully extended, obscured the posteromedial space. In
addition, specific examination techniques, like the trans-notch
view and assessment of the medial meniscus posterior horn
mobility, are necessary for their diagnosis, leading to them being
termed “hidden lesions.”
Their significance has risen in line with the quest to perfect ACL
reconstructions, as ramp lesions affect both anterior and
rotational knee stability. In the literature, ramp lesions are
typically def ine d as longitudinal or oblique superior
meniscocapsular junction tears or meniscotibial ligament tears,
often <2 cm, and usually accompanying ACL tears. In this report,
we present the imaging findings associated with a ramp tear in a
young male with multiple ligamentous injuries to the knee.
Case Report
Here, we report a 34-year-old male presented with knee injury
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DOI: https://doi.org/10.13107/jocr.2024.v14.i03.4306
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Dr. Arun AramDr. Iffath Misbah Dr. Aashika Parveen Amir
Case Report
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DOI:
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1Department of Radiodiagnosis, Saveetha Institute of Medical and Technical Sciences, Chennai, Tamil Nadu, India.
Address of Correspondence:
Dr. Iffath Misbah,
Department of Radiodiagnosis, Saveetha Institute of Medical and Technical Sciences, Chennai, Tami Nadu, India.
E-mail: iffathmisbahcp@gmail.com
© 2024 Journal of Orthopaedic Case Reports Published by Indian Orthopaedic Research Group |
Submitted: 28/11/2023; Review: 27/12/2023; Accepted: February 2024; Published: March 2024
Dr. Aadithiyan Sekar
Journal of Or thopaedic Case Reports 2024 March:14(3):Page 105-108
1 1 1 1
Iffath Misbah , Arun Aram , Aashika Parveen Amir , Aadithiyan Sekar
Introduction: Ramp lesions, often associated with anterior cruciate ligament (ACL) injuries, exhibit a varied incidence rate of 9–42%,
increasing with delayed ACL reconstruction. These lesions, resulting from abnormal tibial movements and semimembranosus muscle
contraction, are challenging to diagnose due to their hidden nature in standard magnetic resonance imaging and arthroscopy procedures.
Case Report: This report examines the case of a ramp lesion in the context of a multi-ligament injured knee of a 34-year-old male. The patient
had a complete ACL, medial collateral ligament, and avulsion of the posterior cruciate ligament with a type 1 ramp lesion. These findings were
confirmed by arthroscopy and were treated with arthroscopic reconstruction of the ligament and all inside repair of the ramp lesion. We report
the pertinent imaging findings relevant to the ramp lesions.
Conclusion: Ramp lesions present a significant diagnostic and treatment challenge in orthopedic practice. Enhanced imaging techniques and a
deeper understanding of their pathophysiology are crucial for an accurate diagnosis.
Keywords: Ramp, hidden lesion, magnetic resonance imaging, arthroscopy.
Abstract
Learning Point of the Article:
Ramp lesions are complex and challenging to diagnose due to their hidden nature in standard imaging procedures, necessitating advanced
magnetic resonance imaging techniques or arthroscopic intervention for accurate detection.
A Case Report on the Hidden Lesion of the Knee: Ramp Lesion

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following a collision injury with a moped. He was unable to
weight bear and walk following the injury and was subjected to
an imaging assessment after preliminary management of the
acute knee injury. Plain radiographs of the knee were obtained
and demonstrated an increased valgus opening, indicating a
medial collateral ligament (MCL) injury (Fig. 1). On the MRI,
complete disruption of the mid substance of the ACL and a
minimally displaced posterior cruciate ligament injury were
observed. The lateral collateral ligament was intact; however,
the MCL was torn on the tibial side and found to be retracted.
Regarding the menisci, the Lateral menisci had a complex
posterior horn tear, and the medial meniscus had a horizontal
cleavage tear of the posterior horn. Strikingly, there was an
irregularity in the posterior
margin of the menisco-capsular
junction with fluid filling, and
this could be attributed to the
r a m p l e s i o n ( F i g . 2 ) .
Subsequently, he was taken up
for arthroscopic surgery, which
confirmed the presence of a
ramp tear (Fig. 3). The order of
re co ns tr uc ti on wa s A CL
reconstruction, medial and
lateral meniscal repair, ramp
repair, a nd f ina lly, me dia l
collateral ligament repair was
performed. The PCL was left to
conservative management.
Discussion
Ramp lesions, often associated with ACL tears, vary in
inc id en ce fr om 9% to 42% , i nc rea si ng wh en AC L
reconstruction is delayed beyond 3 months. Jiang et al. [1]
found 20 cases of ramp lesions without complete ACL tears,
linked instead to ACL longitudinal splits, suggesting minimal
anterior instability and semimembranosus contraction as
potential causes (Fig. 1). The true prevalence of ramp lesions,
either alone or with ACL tears, is unclear due to difficulties in
detection through MRI and arthroscopy. Notably, their
incidence is consistent across adult and pediatric populations,
contrasting with the higher prevalence of other meniscal
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Journal of Orthopaedic Case Reports Volume 14 Issue 3 March 2024 Page 105-108 | | |
Misbah I, et al
Figure 1: Patho mechanics of Ramp lesion.
Figure 2: Arthroscopic view of the posterior joint, depicting the
ramp lesion (separated capsule from the posterior meniscal
attachment).
Figure 3: T2 weighted magnetic resource imaging demonstrating
the posterior irregularity at the meniscocapsular junction.

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Journal of Orthopaedic Case Reports Volume 14 Issue 3 March 2024 Page 105-108 | | |
injuries in younger age groups [2, 3].
Ramp lesions after an ACL tear are mainly due to excessive
anterior tibia movement, causing semimembranosus muscle
contraction and stressing the surrounding ligaments. This
stress, coupled with the medial meniscus being compressed
between the articular surfaces, leads to these lesions. They can
also result from valgus injuries involving internal tibia rotation
and axial loading or as a contrecoup injury from pivoting
movements causing varus strain and femur rotation on the tibia,
leading to meniscus trapping and tearing.
The sensitivity of 3.0-T MRI (83.3%) was superior to 1.5-T
MRI (67.6%), according to Hatayama et al. [4]. Irregularity at
the posterior margin and complete fluid filling were the most
sensitive findings for detecting ramp lesions on MRI, according
to Yeo et al. [5] and Laurens et al. [6]. Consecutive sagittal
im ag es s er ve to de te rm in e w hi ch reg io ns of th e
meniscocapsular junction and posterior horn are torn. Axial
images help to assess the mediolateral dimensions of the same
lesions. Salient features on MRI [7] are detailed in Table 1.
Meniscal ramp lesions have no consented treatment at the
present time. Research has shown that ramp lesions in the
context of acute ACLR may recover without surgical
intervention if the surrounding biological conditions are
appropriate. Some have suggested that ramp lesions should be
surgically addressed rather than being let to heal on its own due
to the hypermobility of the separated meniscocapsular
component. There are data to suggest that individuals with
similar longitudinal meniscal tear patterns who have ACLR
without first having surgery may benefit from nonsurgical
treatment. This is against the general view that ramp lesions
should be addressed when there is chronic ACL insufficiency
[8-10].
Conclusion
These lesions result from abnormal tibia movement and
semimembranosus contraction, often undetected due to
diagnostic challenges. They occur consistently across all age
groups, unlike other meniscal injuries. Advanced MRI
techniques offer improved detection, with specific imaging
features aiding in their identification. Treatment approaches for
Table 1: Summary of positive and negative findings for ramp lesions.
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Misbah I, et al

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108
ramp lesions remain debated, with some cases responding to
nonsurgical methods, particularly in acute ACLR contexts,
while others advocate for surgical intervention, especially in
chronic ACL insufficiency.
Clinical Message
A suspicious irregularity in the posterior meniscopcapsular junction
should raise suspicion of ramp lesions, and it is imperative to confirm
this during knee arthroscopy by probing the meniscocapsular
junction posteriorly.
Journal of Orthopaedic Case Reports Volume 14 Issue 3 March 2024 Page 105-108 | | |
Declaration of patient consent: The authors certify that they have obtained all appropriate patient consent forms. In the form,
the patient has given the consent for his/ her images and other clinical information to be reported in the journal. The patient
understands that his/ her names and initials will not be published and due efforts will be made to conceal their identity, but
anonymity cannot be guaranteed.
Conflict of interest: Nil Source of support: None
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7. Greif DN, Baraga MG, Rizzo MG, Mohile NV, Silva FD, Fox
T, et al. MRI appearance of the different meniscal ramp lesion
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8. Chahla J, Dean CS, Moatshe G, Mitchell JJ, Cram TR,
Yacuzzi C, et al. Meniscal ramp lesions: anatomy, incidence,
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10. DePhillipo NN, Cinque ME, Chahla J, Geeslin AG,
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How to Cite this Article
Misbah I, Aram A, Amir AP, Sekar A. A Case Report on the Hidden
Lesion of the Knee: Ramp Lesion. Journal of Orthopaedic Case
Reports 2024 March;14(3): 105-108.
Conflict of Interest: Nil
Source of Support: Nil
______________________________________________
Consent: The authors confirm that informed consent was
obtained from the patient for publication of this case report
References
Misbah I, et al