Arthrography of the discoid lateral meniscus

Area of Science:

• Orthopedic Surgery
• Radiology
• Knee Anatomy

Background:

• The lateral meniscus is a C-shaped cartilage crucial for knee joint function.
• Discoid lateral meniscus (DLM) is an uncommon anatomical variant where the meniscus has a disc-like shape.
• DLM can be associated with knee pain and meniscal tears.

Purpose of the Study:

• To analyze the arthrographic findings of discoid lateral meniscus (DLM).
• To classify DLM based on arthrographic and anatomical features.
• To establish diagnostic criteria for intact and torn DLM using arthrography.

Main Methods:

• Review of 985 knee arthrograms to identify cases of DLM.
• Classification of DLM based on shape, size, and arthrographic appearance.
• Analysis of associated knee symptoms and incidental findings.

Main Results:

• Twenty-seven cases of DLM were identified (2.7% prevalence).
• Nineteen cases showed a classic discoid shape; eight presented as a forme fruste.
• DLM was classified into six types based on arthrographic findings.
• Over one-third of DLM cases were incidentally diagnosed during evaluation for medial meniscus tears.

Conclusions:

• DLM exhibits significant variability in size and shape, likely due to combined congenital and environmental factors.
• Some DLM cases may develop secondary to trauma without a congenital predisposition.
• Arthrography is a valuable tool for diagnosing and classifying DLM, with specific criteria for intact and torn menisci.