Meniscii


 - Discussion:
    - semilunar cartilages are extensions of tibial articulation of knee;
    - w/o menisci, tibial articulation is incongruous with the femur; 
    - microscopic features 
    - vascular anatomy 
    - anatomy:
           - medial meniscus
                  - bucket handle meniscus tear 
                  - posterior horn tears of medial meniscus 
           - lateral meniscus
                  - discoid meniscus 
           - ref: A Quantitative Study of the Microstructure and Biochemistry of the Medial Meniscal Horn Attachments
    - load bearing function:
           - menisci distribute forces throughout underlying articular cartilage, thus minimizing point contact;
           - menisci bear 40 to 50% of the total load transmitted across joint in extension and 85% of the compressive load
                   is transmitted through the menisci at 90 deg of flexion;
    - motion characteristics:
           - meniscal motion allows maximal congruency during knee flexion and helps to protect the mensici from injury;
           - in the study by Vedi V, et al (1999), meniscal movement was studied using a dynamic MRI:
                 - w/ wt bearing, anterior horn of medial meniscus moved through a mean of 7.1 mm and posterior horn through 3.9 mm, and
                          there was 3.6 mm of mediolateral radial displacement;
                 - w/ wt bearing, the anterior horn of the lateral meniscus moves 9.5 mm and the posterior horn moves 5.6 mm, and there was
                          3.7 mm of radial displacement;
                 - authors felt that relative immobility of the posterior horn of the medial mensicus may account for its propensity for injury;
    - while secondary stabilizer, menisci do impart some stability to normal knee and more important to the ligament deficient knee;
    - each is attached at its periphery to capsular ligament on medial or lateral side of joint & at its horns to interarticular area of tibia;
    - connecting menisci anteriorly is the transverse ligament.
    - menisci help compensate for incongruence of the bones, and they appear to be involved in rotation by moving on the tibia;
    - as result of sufficient stress (usually rotary in wt-bearing, flexed knee), either meniscus may be torn w/in itself or from its
              peripheral attachment; 
    - ref: Meniscal movement. An in-vivo study using dynamic MRI.

-
MRI Features: 
      - Precision in the diagnosis of meniscal lesions: a comparison of clinical evaluation, arthrography, and arthroscopy.
      - Magnetic resonance imaging of a symptomatic meniscal ossicle.


- Management of Meniscus Tears:
 
       -
Meniscal Repairs 
              - ref: The Effect of Knee Flexion Angle on Neurovascular Safety of All-Inside Lateral Meniscus Repair: A Cadaveric Study
       - Menisectomy:
              - references:
                     - Dynamic Contact Mechanics of the Medial Meniscus as a Function of Radial Tear, Repair, and Partial Meniscectomy
                     - A long-term follow-up study of total meniscectomy in children
                     - Partial versus total meniscectomy. A prospective, randomised study with long-term follow-up
                     - Arthroscopic treatment of meniscal cysts.
                     - Lesions of the menisci. Autopsy incidence in adults less than fifty-five years old
                     - Total meniscectomy in adolescents. A 40-year follow-up


The knee joint meniscus. A fibrocartilage of some distinction.



Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Thursday, June 23, 2016 6:50 pm