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| Year : 2005 | Volume
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| Issue : 1 | Page : 75-76 |
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| Ultrasound diagnosis of lateral meniscus cyst |
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DH Thakkar
Plot no 349/1, Sector no 22, Gandhinagar, 382022., India
Click here for correspondence address and email
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Keywords: Lateral Meniscus cyst, ultrasound
How to cite this article:
Thakkar D H. Ultrasound diagnosis of lateral meniscus cyst. Indian J Radiol Imaging 2005;15:75-6 |
 Introduction | |  |
A 33 years old female presented with pain on the lateral aspect of left knee joint off and on since three and half years. There was acute exacerbation of pain since last three days. She was advised radiograph of left knee joint and sonography to see for meniscus.
Plain radiograph of left knee joint revealed- joint space is normal. No evidence of lytic or sclerotic lesion is seen. No definite evidence of bony injury is seen.
On sonography of left knee joint with high frequency broad- band linear transducer, anterior horn and posterior horn of medial meniscus appear normal. Genu of medial meniscus was not evaluated by sonography. Patellar tendon appear normal. Medial collateral and lateral meniscus involving the anterior horn, genu and posterior horn measuring 27 x 25 mm. No definite evidence of cystic lesion is seen in the popliteal fossa. Cruciate ligaments are not evaluated by sonography. Patellar tendon and quadiceps tendon appear normal. Popliteal artery and vein appear normal. On the basis of sonography findings diagnosis of lateral meniscus cyst involving the anterior horn, genu and posterior horn was suggested.
| Discussion | | |
Sonography is an excellent technique with which to visualize the extensor tendons of the knee. Because both the quadriceps and the patellar tendons may be slightly concave anteriorly when the knee is extended and at rest, scans should be obtained during contraction of the quadriceps muscle or with the knee flexed, which straightens the tendons and eliminates the hypoechoic artifact. The quadriceps tendon comprise four tendons (the tendons of rectus femoris, vastus lateralis, vastus medialis and vastus intermedius muscles), which are not usually distinguished sonographically as separate structures. The quadriceps tendon lies underneath the subcutaneous fat and anterior to a fat pad and to the collapsed suprapatellar bursae. On transverse scan the quadriceps tendon is oval. The patellar tendon extends from the patella to the tibial tuberosity, over a length of five to six cm. The subcutaneous prepatellar and infrapatellar bursa are not visible. The deep infrapatellar bursa may appear as aflattened, anechoic structure two to three mm thick. Sonography has been used in the evaluation of collateral ligaments, but normal ligaments are not always easily delineated from the article capsule and from the surrounding subcutaneous tissue. Anterior and posterior horns of medial and lateral meniscus appear as a hyperechoic triangular area beneath the respective collateral ligaments.As a rule cruciate ligaments are far better assessed with MRI. Though the lateral meniscus is rarerly injured, yet cyst of the lateral meniscus is commoner than that of the medial meniscus. A meniscal cyst is an accumulation of fluid in association with an adjacent meniscal tear extending from the joint surface to the meniscus to its outer border. Joint fluid is forced through the tear as the patient walks and accumulates at the meniscocapsular margin. Thus it is a false cyst, and not lined by synovium. They present typically as a hard tense mass adjacent to the joint line. On sonography it is seen as a anechoic area with few soft internal echoes depending on the protein content of the fluid. The anechoic area is not always oval like other cysts but triangular with the base towards the respective collateral ligament.
| Conclusion | | |
Ultrasound in conjunction with the history and clinical examination can prove to be a simple, noninvasive, cost effective, real time, dynamic and effective modality to asses the tendons, ligaments and meniscus around the knee joint.[3]
| References | | |
| 1. | Nata Grobbelaar and J. Antonio Bouffard: Sonography of the knee, A pictorial review. Seminars in Ultrasound, CT and MRI. Vol 2 No 3, June 2000, pp244-245.  |
| 2. | P.W.P Bearcrot and A.K. Dixon: Joint disease MRI aspects, Grainger and Allison's Diagnostic radiology. Vol3, p 2038. |
| 3. | S. Das: A Manual On Clinical Surgery, 3rd Edition, P 166. |
Correspondence Address:
D H Thakkar
Plot no 349/1, Sector no 22, Gandhinagar, 382022.
India
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/0971-3026.28751
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