Discoid meniscus is a rare human anatomy variant that usually affects the lateral meniscus of the knee. Usually someone with this anomaly has no complaints; however, may appear as pain, swelling, or a broken sound that is heard from the affected knee. Strongly suggestive findings on magnetic resonance imaging include a thickened meniscal body seen on more than two adjacent pieces.
Video Discoid meniscus
Description
The Watanabe classification of the lateral meniscus of the discoid is: (A) Incomplete, (B) Complete, and C) Witchberg-ligament variant Usually, the meniscus is a thin crescent-shaped sickle bone located between the weight of the joint bearing from the femur and tibia. It is attached to the lining of the knee joint along the peripheral and serves to absorb about one third of the impact load seen on the surface of joint cartilage and also provides some degree of stabilization for the knee. There are two menisci in the knee joint, with one on the outside (away from the midline) into the lateral meniscus and the deep (towards the midline) medial meniscus. Discoid meniskus is a kongenital ankle of the knee found in 3% of the population (up to 15% in Asia). This usually affects the lateral meniscus and can be found bilaterally (20%). Instead of the narrow crescent shape, as seen in the normal meniscus above, the discoid penis is thickened, and has a fuller crescent shape. In addition, discoid meniscus is not taper to the center of the joint and shaped like a disc. The thickness of the meniscus, reduced vascular blood supply, and in some cases, weak capsular attachment, makes it more susceptible to tears than with normal meniscus. The anomaly itself is asymptomatic; however, a meniscus tear can cause pain, swelling, and fracture of the affected knee. The discoid meniscus orthopedic classification includes: complete, incomplete or Wrisberg type ligaments as illustrated here. The coverage of the lateral tibia plateau determines the complete or incomplete designation. The type of Wrisberg ligament has an abnormal posterior abnormality by attaching to the posterior cruciate ligament section.
Maps Discoid meniscus
Diagnosis
The normal meniscus transverse diameter is about 10-11 mm; therefore the normal meniscus body will be seen only on 2 MR wedges with 4-5 mm sagittal slices. Discoid meniscus should be considered if there are more than two adjacent body segments. However, this method can cause false negatives when evaluating people with the discrete meniscus Wrisberg variant as it maintains a narrow crescent shape. The coronal and radial features of the meniscus are useful for demonstrating the expansion of the meniscus that deviates into the joints as seen here. In coronal images, it is diagnosed when the horizontal measurement between free margins and body edges is more than 1.4 cm. Rarely, X-rays may indicate widening of lateral joint space, squaring lateral condyle, cupping of the lateral tibial plateau and hypoplasia of the lateral tibia spine suggesting a discoid meniscus.
Maintenance/Management
In patients who complain of acute knee pain, an X-ray study will be performed to rule out bone pathology such as fractures. Because it is difficult to diagnose meniscal anomalies with X-rays, MRI will be necessary to visualize the meniscus diskologist. If the patient has no symptoms and does not complain of significant locking sensations in the knee or pain, the treatment is conservative and consists of stretching and strengthening exercises for quadriceps and hamstring muscles. "In cases where there is a significant disability, surgical excision may be necessary.When the meniscus diskoid is severely damaged, a total meniscal excision may be necessary.In most cases where the meniscus is intact, partial excision to maintain the bearing may be enough."
See also
- Knee pain
- Knee osteoarthritis
- Meniscal cyst
References
External links
- Discoid Meniscus in eMedicine
Source of the article : Wikipedia
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