Ultrasound Case of the Month

November 2013

81 year old woman withchronic left knee pain

Grayscale Images of the Left Knee

Trans image at the trochlea (knee flexed)

Trans image at the far lateral aspect of the femorotibial joint

Grayscale Images of the Left Knee

There are thin, hyperechoic linear foci within the hyaline cartilage of the trochlea and lateral femorotibial compartment

Diagnosis: Chondrocalcinosi

s

Chondrocalcinosis

• Multiple causes, the most common due to calcium pyrophosphate deposition disease (CPPD)

• Others include:• Gout• Wilson disease• Hemochromatosis• Ochranosis

• Hypophosphatasia• Hyperaparathyroidism• Hypomagnesemia• Hypothyroidism

Ultrasound of the Normal Knee

• Hyaline cartilage is normally homogeneously hypoechoic

• Trochlear and anterior surfaces of the femoral condyles are best seen with the knee flexed Trochlear

cartilage

Ultrasound of the Normal Knee

• Sharp anterior and posterior interfaces

• Ultrasound is limited in evaluating the far inner margins of both the lateral and medial femorotibial joints Far lateral aspect of the lateral femoral

condyle

Ultrasound of the Knee with Chondrocalcinosis

• Calcifications are within the hyaline cartilage

• Parallel to the femoral condyle

Ultrasound of the Knee with Chondrocalcinosis

• Acoustic shadowing typical of calcifications on ultrasound are not seen because these calcifications are small and do not function as a barrier to sound penetration

Ultrasound of the Knee with Chondrocalcinosis

• This heterogeneous calcification corresponds to meniscal (fibrocartilage) calcification seen on the ultrasound

• In our case, the patient had radiographs performed seven years prior, which also demonstrated chondrocalcinosis

Ultrasound of the Knee with Chondrocalcinosis

The lateral meniscus is extruded into the lateral joint space in this patient secondary to meniscal tear

Fem condyle Tibial plateau

Further Reading…

Foldes K. Knee chondrocalcinosis: An ultrasonographic study of hyalin cartilage. J of Clin Im. 2002; 26:194-196Kaushik S, et al. Effect of Chondrocalcinosis on the MR Imaging of Knee Menisci. AJR. 2001; 177:905-909.Sofka CM, Adler RS, Cordasco FA. Ultrasound diagnosis of chondrocalcinosis in the knee. Skel Rad. 2002; 31:43-45