Dynamic ultrasonography of the medial meniscus during walking in knee osteoarthritis

Medial meniscal extrusion (MME) is a risk factor for the progression of knee osteoarthritis (OA). MME evaluation is crucial and it is commonly performed using magnetic resonance imaging (MRI) or static ultrasonography. We developed a prototype flat-shaped ultrasound transducer to visualize the actual meniscal movements during walking.

The aim of this study was to investigate whether it is feasible to visualize and evaluate the meniscal movements during walking using the novel flat-shaped ultrasound transducer for dynamic ultrasonography.

Six participants who were diagnosed with primary unilateral or bilateral tibiofemoral knee OA on radiography (mean age, 67.1 ± 9.9 years; males/females, 4/2) and six healthy volunteers without any symptoms in their knees (mean age, 26.3 ± 4.0 years; males/females, 4/2) were enrolled in this study. The movement of the medial meniscus during walking was visualized using the novel transducer and the gait motion was recorded as video images that were synchronized with the ultrasonogram. MME and ΔMME (the difference between the minimum and maximum MME during the stance phase of the gait cycle) were evaluated in those with OA and compared with those in healthy volunteers.

In both groups, MME was visualized clearly in the stance phase. The mean values of MME and ΔMME in the knee OA group were significantly greater than those in the control group (P < .01).

Dynamic meniscal movement during gait can be evaluated with the specially developed novel ultrasound transducer. Our approach will be helpful in unveiling unknown pathological mechanisms in knee OA.