Pitfalls in knee arthrography.

Sources of error in performing and interpreting knee arthrograms are discussed. Normal anatomic structures and technical factors can simulate tears in most areas of both the medial and lateral menisci. These pseudotears, as well as unrecognized true tears, occur more commonly in the posterior horn of the medial meniscus. Inferior meniscal recesses and coronary ligament irregularities of the posterior medial meniscus often represent incomplete tears. Diagnostic, etiologic, and therapeutic aspects of these recesses, or pseudorecesses, are discussed. Excessive intra-articular positive contrast medium may become localized and simulate a loose body in the joint.