High resolution sonography for analysis of meniscal injuries.

High resolution ultrasonography was done prospectively in 51 adult patients with clinically suspected meniscal injuries to evaluate the sensitivity and specificity of ultrasonography as a primary diagnostic tool and to see if it was possible to evaluate the site, extent and size of the tear. All cases were confirmed arthroscopically; ultrasonographic examination revealed inhomogenecity in 45 cases and this was accurate in 40 cases; in 3 cases ultrasonography gave a false positive result and in 2 cases the wrong meniscus was shown to be torn. The six cases with no findings on ultrasonography were proven to have no meniscal tear. The sensitivity of ultrasonography as a screening test to rule out meniscal injuries was thus 100%; on the other hand the specificity (false positive screening test) was 54%. It was no possible to determine the site, size or extent of the tear by the ultrasonographic examination. Even though magnetic resonance imaging is more accurate in giving an exact diagnosis, ultrasonography is an excellent primary diagnostic tool which is inexpensive with no side-effects, is readily available and has very good sensitivity and a reasonable specificity.