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Basic Knee Imaging RSSA Durban 2008 . Richard de Villiers Van Wageningen and Partners. Aims . Anatomy of the Meniscus Imaging protocol. Terminology. Speak the same language as your referrer Keep up to date with the relevant terminology. Anatomy. Meniscal anatomy Attachments.
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Basic Knee ImagingRSSA Durban 2008 Richard de Villiers Van Wageningen and Partners
Aims • Anatomy of the Meniscus • Imaging protocol
Terminology • Speak the same language as your referrer • Keep up to date with the relevant terminology
Anatomy • Meniscal anatomy • Attachments
Basic anatomy Medial meniscus Lateral meniscus
Morphology • Wedge-shaped • Semilunar ( C -shaped) • Surface • Superior • concave • Inferior • flat • Fibrocartilage (collagen fibres) • Fibres • superficial • circumferential hoop • radial tie
A.Superficial layer a ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° mesh-like matrix of fine fibrils measuring 100μ
Superficial layer a 100 micrometre
° ° ° ° ° ° ° ° ° ° ° ° ° c ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° B.Circumferential hoop fibres b rope-like collagen fibre bundles c. smaller radial fibres - reeinforcement
a b
° ° ° ° ° ° ° ° ° ° ° ° ° c ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° ° C. Radial Tie fibres b -reinforcement
Terminology Red-white zone Free edge Menisco-capsular junction Peripheral zone (outer) Red zone Central zone Inner White zone
Vascularity • From the genicular vessels • Extent • Medial (10-30% of width) • Lateral (10-25% of width)
Arnoczky SP (1992) In: Mow VC, Arnoczky SP, Jackson DW (Eds) Knee meniscus: Basic and clinical foundations. Raven Press, New York
Relevance • If tear involves outer, vascular 1/3 (3-5 mm from capsule) • Surgical repair / or conservative • If tear involves inner,-non-vascular 1/3 • Partial / total meniscectomy
Medial Meniscus • Size (AH < PH) • AH ( 7.6 mm) • Body ( 9.6 mm) • PH ( 10.6mm)
Lateral meniscus • Size ( AH = PH) • AH (10.2 mm) • Body (11.6 mm) • PH (10.6 mm)
Attachments • Menisci maintained in optimal position • Various direct and indirect attachments to the tibia and femur. • Peripheral attachments to capsule
Medial Meniscus • Attachments • AH • Transverse ligament • Anterior root ligament • Body (capsular) • Meniscofemoral • Meniscotibial ( coronary) • Minor capsular attachments • PH • Posterior root ligament
Radiologist attending this lecture according to the attendance register
Lateral meniscus • Attachments • AH • Transverse meniscal ligament • Root ligament • Body • Capsular ligaments • Superior and inferior • To ITB • NOT attached to the LCL • PH • Meniscofemoral ligaments • Humphrey and Wrisberg • Popliteomeniscal ligaments • Meniscal struts • Root ligament
Transverse meniscal ligament • The menisci are attached to each other anteriorly by the transverseligament • 44 - 58 % incidence
Root attachments Cannabis sativa – Durban Poison • Critical attachment sites to the central tibial plateau. • Resist hoop stress • Well-defined relations to each other and to the cruciate ligament insertions • The Meniscal Roots: Gross Anatomic Correlation with 3-T MRI FindingsAm. J. Roentgenol., May 2007; 188: W446 - W450 Jeffrey M. Brody, Michael J. Hulstyn, Braden C. Fleming, and Glenn A. Tung.
Meniscofemoral ligaments • Ligaments of Humphrey and Wrisberg. • Superomedially • Posterior horn of thelateral meniscus to the lateral aspect of the medial femoral condyle. • Name based on their location • Either 70% • Both 6% • Minor role
Ligament of Wrisberg • Posterior • Larger • Inserts into the medial femoral condyle.
Ligament of Humphrey • Anterior • Smaller • 1/3 of PCL diameter
Popliteomeniscal ligaments • Superior and inferior struts • Anchor the posterior horn of the lateral meniscus to the capsule
MM capsular attachments Meniscotibial/femoral ligaments • MM attached via the deep portion of the MCL and the • meniscofemoral (f) and • meniscotibial (t) ligaments
Minor capsular attachments • Periphery of menisci usually attach to capsule via synovial attachments
Oblique menisco-meniscal ligament • Normal variant • runs obliquely from the anterior horn of one meniscus to the posterior horn of the opposite meniscus. • 1% to 4% • mimic a meniscal tear
Our institution 1.5 T Siemens Symphony Dedicated knee coil Well-trained, dedicated MR technicians Sagittal, axial and coronal PD/ PDFS PD for anatomy PDFS for pathology Occasionally MR arthrogram ( ? CT > MR) Post-surgical ? Meniscal retear Stability of osteochondral lesion Plica WE-DESS 1mm cuts : subtle meniscal & chondral abN 3D MPR GRE Subtle meniscal abN T1 Fracture/ tumour T2 Ganglion/cyst PC-T1FS Synovitis Infection Tumour MRI Protocols
Thank you • www.samsig.co.za