synonyms: "Popping knee syndrome," discoid meniscus
Discoid Meniscus ICD-10
Discoid Meniscus ICD-9
- 717.5 (derangement of meniscus, not elsewhere classified)
Discoid Meniscus Etiology / Epidemiology / Natural History
- Discoid menisus is a congenital abnormality caused by failure of apoptosis during development in utero. No known genetic cause.
- Prone to tearing and often with minimal trauma.
- Contralateral discoid menisci are noted in 20% of patients.
Discoid Meniscus Anatomy
Discoid Meniscus Clinical Evaluation
- C/O knee pain with mechnical symptoms.
- Meniscal symptoms in a child <10y/o.
- Classic complaint is popping with the knee in extension.
Discoid Meniscus Xray / Diagnositc Tests
- Lateral and weight bearing A/P knee films, may show joint space widening, squaring of the lateral condlye, cupping of the lateral tibia plateau or a hypoplastic lateral intercondylar spine.
- MRI: generally clearly shows abnormal meniscal morphology.
Discoid Meniscus Classification / Treatment
- Incomplete (Type II):
- Complete (Type I):
- Wrisberg's variant Type III): discoid meniscus is only attached to the medial femoral condyle via the meniscofemoral (Wrisberg) ligament. Can displace into the notch with knee extension.
- Incidental discoid meniscus found during knee arthroscopy do not require treatment
- Tears in discoid menisci are treated with excision of the torn portion and saucerization. Repair is indicated for peripheral detachments.
Discoid Meniscus Associated Injuries / Differential Diagnosis
Discoid Meniscus Complications
Discoid Meniscus Follow-up Care
- 71% excellent, 24% good, 5% fair for arthroscopic lateral menisectomy in patients with symptomatic discoid lateral meniscus. (Aglietti P, Am J Knee Surg 1999;12:83).
Discoid Meniscus Review References
- Insall & Scott Surgery of the Knee: Expert Consult - Online and Print, 5e, 2011
- DeLee & Drez's, Orthopaedic Sports Medicine: 3e; 2009
- Good CR, Green DW, Griffith MH, Valen AW, Widmann RF, Rodeo SA. Arthroscopic treatment of symptomatic discoid meniscus in children: classification, technique,and results. Arthroscopy. 2007 Feb;23(2):157-63.
- Kramer DE, Micheli LJ. Meniscal tears and discoid meniscus in children:diagnosis and treatment. J Am Acad Orthop Surg. 2009 Nov;17(11):698-707.