[Clinical and sonographic meniscus diagnosis]

Clinical examination still plays an important role in diagnosing meniscal tears. The types of sensitive nerves in the knee joint are responsible for nonspecific pain, which is often correlated with too little specificity in meniscal tests. Ultrasound examination of meniscal structures of the knee joint has been debated extensively in recent years. Criticism of this noninvasive technique was due to small patient groups, improper technical and inaccurate manual standards. Since 1988 ultrasound of the tibial meniscus has become a standard technique in our Department of Orthopaedic Surgery with defined criteria of the intersecting plane and evaluation of ultrasound images. A prospective follow-up study during 6/1988 and 5/1993 including 1186 ultrasound examinations before arthroscopy, was performed. The sensitivity for ultrasound of the lateral meniscus was 58% and for the medial meniscus 83%. Specificity with 98% for the lateral and 90% for the medial meniscus was good. Sonographic detection of meniscal tears depends on the shape and location of meniscal tears. This has been shown by experimental studies in cadavers. A follow-up study including 113 knee joints was performed to prove the value of clinical and ultrasound examination in relation to arthroscopy. The sensitivity of sonography for medial meniscus was 81% and 40% for the lateral meniscus. Although the sensitivity of the clinical examination was 81% (medial) and 47% (lateral), the low specificity of 70% for meniscus tears indicated that it was because of false-positive clinical evaluation of meniscal disorders. In young patients with reflectory muscle spasm and those with acute trauma of the knee joint, clinical examination of the meniscal structures showed poor results. In these cases, too, ultrasound examination showed advantages. Ultrasound of the knee joint meniscus is noninvasive, reproducible and low cost. In cases of uncertain clinical results, ultrasound offers a good opportunity to visualize meniscal disorders.