2. INTRODUCTION
Introduction
Abnormal development of the meniscus leads
to a hypertrophic and discoid shaped meniscus
discoid meniscus is larger than usual
also referred to as "popping knee syndrome".
Epidemiology
incidence
present in 3-5% of population
location
usually lateral meniscus involved
25% bilateral
3. Classification
(A) The complete type is the disc-shaped meniscus that completely covers
the lateral tibial plateau and has a normal posterior attachment. (B) The
incomplete type has a semilunar shape and normal posterior attachment,
but it covers less than 80% of the lateral tibial plateau. (C) The Wrisberg
type is more normally shaped compared to the complete or incomplete type
of discoid meniscus, but it lacks the usual posterior meniscal attachments
(coronary ligament), and only the Wrisberg ligament connects the posterior
horn of the lateral meniscus.
Watanabe classification
5. Imaging
recommended views are AP and lateral of knee
findings
- widened joint space (up to 11mm)
- squaring of lateral condyle with cupping of lateral
tibial plateau
- hypoplastic lateral intercondylar spine
Radiographs
6. MRI
Indication is study of choice for suspected symptomatic
meniscal pathology
findings are as follows.
- diagnosis can be made with 3 or more 5mm sagittal
images with meniscal continuity ("bow-tie sign")
- sagittal MRI will show abnormally thick and flat
meniscus
- coronal MRI will show thick and flat meniscal tissue
extending across entire lateral compartment
indications and finding
8. Management Non operative is observation
indications is asymptomatic discoid meniscus without
tears.
9. Operative
management
- Operative procedure is partial meniscectomy and
saucerization.
- indications are
1) pain and mechanical symptoms
2) meniscal tear or meniscal detachment
- technique
obtain anatomic looking meniscus with debridement or
Repair meniscus if detached (Wrisberg variant)