Discoid Meniscus

DefinitionDiscoid Meniscus


Round or "D" shaped rather than crescenteric meniscus

- occupies > 70% of tibial surface

- 90% occur on lateral side





- 1:100

- usually presents in children & adolescents


Case reports of

- medial

- bilateral

- medial and lateral in same knee








1.  Failure of resorption of embryological meniscus centre

- however the lateral meniscus is never discoid during normal development


2. Lack of normal fixation to posterior tibia

- discoid shape 2° hypertrophy of posterior horn

- due to excessive motion




1.  Younger patients / adolescents < 15

- pain is commonest complaint

- clicking over lateral side

- recurrent effusions

- locking


2.  Adults

- may never be symptomatic

- some adults present with MRI showing discoid meniscus

- theory that meniscus is protective in these people

- have gone most of life without tearing meniscus

- only resect if unstable tear




Reproduce clicking at 110° flexion


Lateral joint line tenderness / mass




Limitation of extension / FFD


Classification Watanabe


1.  Complete

- entire articular surface of tibial plateau covered by thickened abnormal meniscus

- minimal symptoms

- stable - i.e. capsular attachments intact


Complete Discoid MeniscusComplete discoid meniscus 2Complete Discoid Meniscus 3


2. Incomplete 


Normal peripheral attachments but not as extensive as complete type


Incomplete Discoid Meniscus


3. Wrisberg Type 



- large posterior horn with no attachment to tibial plateau

- entire posterior portion hyper-mobile

- only attachment is Wrisberg Ligament


Most symptomatic

- displaced into intercondylar notch in extension




Widened joint space


Discoid Meniscus Flattened Condyle Widened Joint Space


Flattening or cupping of plateau


Flat LFC


Hypoplastic Lateral Tibial Spine




Obviously enlarged LM

See meniscus on 3 consecutive cuts


Discoid Meniscus MRI 1Discoid Meniscus MRI 2Discoid Meniscus MRI 3


Discoid Meniscus with intrasubstance degeneration






There is a protective element to lateral meniscus

- resect only if painful tear / young patient




Convert unstable meniscus to a stable contoured one




1.  Stable 

- partial central meniscectomy / saucerisation


2.  Unstable (Wrisberg type) 

- posterior capsular stabilisation / repair +/- saucerisation


Ahn et al Arthroscopy 2008

- 23 patients treated with posterior repair and partial central meniscectomy

- no reoperation at 51 months

- good symptomatic relief


3.  Prophylactic meniscectomy

- no role


Technique Saucerisation



- demanding and technically difficult

- takes 1 - 2 hours

- difficult to know how much to resect

- need to ensure don't damage chondral surfaces

- reported cases of rapid and severe chondrolysis post resection in young patients



- make incision with scissors in medial aspect

- resect posterior part

- saucerise laterally and anteriorly

- need to ensure don't detach anterior horn


Discoid Meniscus Saucerisation 1Discoid Meniscus Saucerisation 2Discoid Meniscus Saucerisation 3


Discoid Meniscus Saucerisation 4Discoid Meniscus Post Saucerisation