Knee Joint Ultrasound: Scanning Protocol, Projections, and Norms
Structure of the Scanning Protocol
A comprehensive ultrasound examination of the knee joint covers several anatomical groups. According to Fundamentals of Musculoskeletal Ultrasound (Jacobson, 2026), the standard protocol includes the assessment of the following structures:
- Extensor apparatus: quadriceps tendon, patella, patellar tendon.
- Medial and lateral collateral ligaments.
- Iliotibial tract, biceps femoris tendon, popliteus tendon, common peroneal nerve.
- Popliteal area — exclusion of popliteal (Baker's) cyst.
- Limited assessment of the menisci.
- Evaluation of joint effusion, synovial hypertrophy, and intra-articular bodies.
Projections for Assessing Hyaline Cartilage
The transverse infrapatellar view is described for measuring the thickness of the distal femoral cartilage — an ultrasound technique proposed for quantitative assessment of femoral bone cartilage thickness (Lee SW et al., J Ultrasound Med, 2020). Specific reference values for hyaline cartilage thickness are not provided in the source fragments [clarify].
Assessment of Ligamentous Apparatus Using Bony Landmarks
To identify the medial and lateral tendons and ligaments of the knee, it is recommended to use bony landmarks as a simple method for localizing structures (De Maeseneer M et al., AJR Am J Roentgenol, 2002). The features of visualizing the proximal lateral collateral ligament on ultrasound and MRI (Falkowski AL et al., J Ultrasound Med, 2022) and potential errors in the bifurcation of the distal biceps femoris tendon (Smith J et al., J Ultrasound Med, 2011) are separately described.
Joint Effusion and Recess
Effusion assessment is part of the standard protocol. An example conclusion from the source includes the phrase "moderate-sized joint effusion without synovial hypertrophy and intra-articular bodies." Numerical thresholds for effusion volume or recess thickness are not specified in the fragments [clarify].
Hyaline Cartilage in Crystalline Arthropathies
Ultrasound assessment of hyaline cartilage is significant in gout and calcium pyrophosphate deposition disease (Filippucci E et al., Osteoarthritis Cartilage, 2009). The deposition of monosodium urate crystals on the cartilage surface and their disappearance upon achieving stable normouricemia is described (Thiele RG, Schlesinger N, Rheumatol Int, 2010).
Frequently asked questions
What structures are included in the standard knee ultrasound protocol?
Extensor apparatus (quadriceps tendon, patella, patellar tendon), collateral ligaments, iliotibial tract, biceps femoris, popliteus tendon, common peroneal nerve, popliteal area (Baker's cyst), menisci, and joint effusion.
Which projection is used to measure femoral cartilage thickness?
The transverse infrapatellar view is a technique for measuring the thickness of the distal femoral cartilage (Lee SW et al., J Ultrasound Med, 2020).
What are the norms for hyaline cartilage thickness provided by the source?
Specific numerical reference values for hyaline cartilage thickness are not presented in the source fragments [clarify].
How can the identification of knee ligaments be facilitated during scanning?
It is recommended to use bony landmarks as a simple method for identifying medial and lateral tendons and ligaments (De Maeseneer M et al., AJR, 2002).
What is assessed in the study of joint effusion?
The presence and volume of effusion, synovial hypertrophy, and intra-articular bodies; the conclusion indicates the size of the effusion (e.g., moderate). Numerical thresholds are not provided in the fragments [clarify].