Ultrasonographic Assessment of the Normal Femoral Articular Cartilage of the Knee Joint: Comparison with 3D MRI

Abstract

Objective. Ultrasonography (US) has a promising role in evaluating the knee joint, but capability to visualize the femoral articular cartilage needs systematic evaluation. We measured the extent of this acoustic window by comparing standardized US images with the corresponding MRI views of the femoral cartilage. Design. Ten healthy volunteers without knee pathology underwent systematic US and MRI evaluation of both knees. The femoral cartilage was assessed on the oblique transverse axial plane with US and with 3D MRI. The acoustic window on US was compared to the corresponding views of the femoral sulcus and both condyles on MRI. The mean imaging coverage of the femoral cartilage and the cartilage thickness measurements on US and MRI were compared. Results. Mean imaging coverage of the cartilage of the medial femoral condyle was 66% (range 54%–80%) and on the lateral femoral condyle 37% (range 25%–51%) compared with MRI. Mean cartilage thickness measurement in the femoral sulcus was 3.17 mm with US and 3.61 mm with MRI (14.0% difference). The corresponding measurements in the medial femoral condyle were 1.95 mm with US and 2.35 mm with MRI (21.0% difference), and in the lateral femoral condyle, they were 2.17 mm and 2.73 mm (25.6% difference), respectively. Conclusion. Two-thirds of the articular cartilage of the medial femoral condyle, and one-third in the lateral femoral condyle, can be assessed with US. The cartilage thickness measurements seem to be underestimated by US. These results show promise for the evaluation of the weight-bearing cartilage of the medial femoral condyle with US.

The ultrasound assessment of osteoarthritis: the current status

“…To address this issue, Kauppinen et al (2021) studied 20 healthy knees with US and isotropic 0.6 mm MRI with 90-degree flexed knee to assess the capability of US to visualize the femoral articular cartilage. The authors concluded that up to two-thirds of the articular cartilage of the medial femoral condyle, and one-third in the lateral femoral condyle, can be assessed by US [ 1 ].…”

A Guide to Performing Seated, Foot-On-Floor Position Ultrasound Guided Knee Injections Targeting the Medial & Lateral Parapatellar Bursae & Their Channels

“…Studies have described that optimal intracondylar hyaline cartilage resolution is achieved with the probe in transverse suprapatellar plane with the knee flexed to 90 degrees. [24] If the structures with underlying cartilage are to be targeting for injection-aspiration, it therefore follows that the SKIF position approximates of 90 degrees of knee flexion, may also optimally distinguish cartilage from closely approximated bursal structures, thereby prevented procedural cartilage needle sticks. Though the SPB is a common target for knee aspiration-injection there are other pitfalls to successful tribursal, recess & channel injection procedures.…”

Articular surface integrity assessed by ultrasound is associated with biological characteristics of articular cartilage in early-stage degeneration

“…It requires the examiner to have a relatively high level of operating skills, also the visualization of articular cartilage is limited 13 , 14 . In the case of knee joints, it cannot assess the whole area of the femoral condyle 15 , 16 . However, despite these problems, it is expected to have a great potential in the evaluation of OA cartilage depending on how it is used, because it can evaluate surface tissues with higher resolution than MRI 16 , 17 .…”

“…In the case of knee joints, it cannot assess the whole area of the femoral condyle 15 , 16 . However, despite these problems, it is expected to have a great potential in the evaluation of OA cartilage depending on how it is used, because it can evaluate surface tissues with higher resolution than MRI 16 , 17 . In US images, healthy articular cartilage is detected as a homogeneous hypoechoic thin layer structure between the chondrosynovial and osteochondral margins at different synovial joints, including the knee, elbow, wrist, shoulder, tibiotalar, and metacarpophalangeal joints 14 .…”

“…In US images, healthy articular cartilage is detected as a homogeneous hypoechoic thin layer structure between the chondrosynovial and osteochondral margins at different synovial joints, including the knee, elbow, wrist, shoulder, tibiotalar, and metacarpophalangeal joints 14 . Previous studies have shown that US measurements of articular cartilage thickness mirror those assessed by MRI or contrast-enhanced micro-computed tomography (micro-CT) 16 – 18 . Furthermore, some under-researched US-assisted techniques such as quantitative US techniques and US elastography could show more mechanical properties of the cartilage, which may be applicable for arthroscopy or open surgery in the future 19 , 20 .…”