Sonography of Knee Effusion

Abstract

Objective: A review of the anatomy of the synovial recesses of the knee is important to better understand the different effusion presentations, update the diagnosis criteria of knee effusion based on the measured synovial recesses and discuss the differentiation of some effused recesses from other lesions around the knee. Method: This review focuses on the anatomy of the synovial recesses of the knee and classifies them into three groups (anterior, parameniscal, and posterior recesses), as well as provides an overview on the etiology of knee effusion, its sonographic detection, and diagnosis criteria. Results: Knee effusion is a very common pathological finding in sonography of the knee. The unique joint structure of the knee provides the possibility to host complex synovial recesses. Fluid in some of the synovial recesses is valuable for the diagnosis of knee effusion, while in certain situations, some recesses may impose diagnostic uncertainty. Knowledge of these synovial recesses is essential to avoid diagnostic pitfalls. Conclusion: This review provides an important discussion of the differentiation of some recesses effusions from other lesions around the knee.

Sonographic Diagnosis of Medial Meniscocapsular Separation of the Knee

“…The shape of a meniscal cyst does not change with knee movement or with applied pressure, while the shape of a fluid collection of MCS may change. 13,14 Other important clinical factors are that most patients with meniscal cysts are asymptomatic and have no history of sports injury.…”

“…One consensus theory about the formation of a meniscal cyst is that it is developed from the collection of the synovial fluid through a tear in the articular surface of the meniscus. 12,14 Hence, a meniscal tear can often be found connected to a meniscal cyst during sonography. The shape of a meniscal cyst may be unilobular or multilobular.…”

Diagnostic Dilemmas and Treatment Strategy for Paediatric Non-Traumatic Knee Effusion

“…A knee effusion is defined as presence of increased volume of fluid in the synovial compartment of the knee which is the most common pathological finding in the synovial diseases of knee. It can occur due to traumatic as well as non-traumatic causes [1]. The later includes tumour, crystal deposition, degenerative arthritis, inflammatory arthritis, or infection [2,3].…”

Determination of Normal Reference Values for Meniscal Extrusion Using Ultrasonography During the Different Range of Motion

“…It is a traditional and accepted modality in detecting fluid collection such as abscess, joint effusion, and cellulitis, diagnosis of nerves and tendons discontinuity or even inflammation, and detection and categorization of soft tissue masses. 5,6 The idea of using ultrasound for detecting meniscal injuries goes back to more than 20 years. However, its accuracy and the exact pathological points remain controversial.…”

“…Ultrasonographic (US) study in the diagnosis of orthopedic‐related problems has become more popular in recent years. It is a traditional and accepted modality in detecting fluid collection such as abscess, joint effusion, and cellulitis, diagnosis of nerves and tendons discontinuity or even inflammation, and detection and categorization of soft tissue masses 5,6 …”