Can the sonographic distal vastus medialis thickness be a useful marker to reflect disease progression of knee OA?

초록

Background and aims The objective of this study was to evaluate the correlations between radiologic staging and evaluated ultrasound results of the distal portion of VM muscle thickness in knee OA comparing with the previous mid-thigh level study. Methods Knee OA was graded according to the Kellgren-Lawrence classification. We measured the femur length using the distance from the surface landmark of ASIS to the lateral border of the patella. Then the mid-level (50%), and distal 25% of the femur level were calculated. At the mid-level, thickness of the rectus femoris, vastus intermedius, and VM was measured, and at the distal 25% level, VM muscle thickness was measured (Fig. 1). Results We included 30 patients (20 women and 10 men) aged 20 to 80 years. The subgroup was divided into two groups according to the severity of knee OA (Group 1: K-L grade 0-1, Group 2: K-L grade 2-4). A significant negative correlation between the thickness of some anterior thigh muscle and stage of knee OA was noticed. When the body mass effect was considered, it showed a more significant result between groups 1 and 2 (Table 1). With subgroup analysis, a statistically significant difference was determined in every muscle we investigated (Table 2). Conclusions Individual thigh muscle thickness showed a negative correlation with the progression of knee OA. With the easy accessibility and high reproducibility, exploring the thickness of the distal portion of VM can be a useful indicator for severe knee OA patients.