Foot and Ankle surgery, The Third Hospital of Hebei Medical University, Hebei, China.
Imaging Department, The Third Hospital of Hebei Medical University, Hebei, China.
BMC Musculoskelet Disord. 2023 Oct 31;24(1):857. doi: 10.1186/s12891-023-06976-9.
Varus-valgus lower alignment is a risk factor for patellofemoral osteoarthritis, but malalignment alone affect not only the tibiofemoral joint but also the patellofemoral joint. The aim of the present study was to analyse the contact area of patellofemoral joint in varus alignment and valgus alignment of healthy subjects using magnetic resonance imaging.
Twenty-six healthy subjects with valgus lower limb alignment (Group I, n = 26) and twenty-six volunteers with varus lower limb alignment (Group II, n = 26) was performed. An MRI scan was used to capture and measure the patellofemoral joint articular cartilage contact area at different degrees of knee flexion (20°, 40°,60°) in passive movement. All subjects were categorized on the basis of the global limb alignment and mechanical alignment of the femur and tibia. Varus alignment is hip-knee-ankle angle ≥ 3°; and valgus alignment is hip-knee-ankle angle ≥ - 3°. To obtain medial facet contact area and lateral facet contact area for each slice, the length of each respective line of contact was multiplied by the 5 mm slice thickness.
The overall joint contact area increased from 168.0 ± 20.5 mm at 20° knee flexion to 334.4 ± 30.5 mm at 60° knee flexion in group (I) The overall joint contact area increased from 178.0 ± 18.9 mm at 20° knee flexion to 328.9 ± 27.2 mm at 60° knee flexion in group (II) There was a significant difference in lateral facet contact area between group I and group II at 40° of knee flexion. There was significantly different in medial facet contact area between group I and group II at 20° and 40° of knee flexion.
Throughout the knee movement, the contact area on the lateral facet of the patellofemoral joint was greater in the valgus group. In the early phase of knee flexion, the contact area of the medial patellofemoral joint was larger in the varus group. Lower alignment is an important factor in patellofemoral joint degeneration.
内翻-外翻下肢对线不良是髌股关节炎的危险因素，但对线不良不仅影响胫股关节，还影响髌股关节。本研究旨在使用磁共振成像分析健康受试者在膝内翻和膝外翻时髌股关节的接触面积。
对 26 例膝内翻下肢对线不良的健康受试者（I 组，n=26）和 26 例膝外翻下肢对线正常的志愿者（II 组，n=26）进行研究。使用 MRI 扫描在被动运动时拍摄并测量不同膝关节屈曲度（20°、40°、60°）时髌股关节关节软骨的接触面积。所有受试者均根据下肢整体对线和股骨与胫骨机械对线进行分类。膝内翻是指髋膝踝角≥3°；膝外翻是指髋膝踝角≥-3°。为了获得每个切片的内侧关节面接触面积和外侧关节面接触面积，将每个接触线的长度乘以 5mm 的切片厚度。
I 组的总关节接触面积从膝关节 20°屈曲时的 168.0±20.5mm 增加到 60°屈曲时的 334.4±30.5mm。II 组的总关节接触面积从膝关节 20°屈曲时的 178.0±18.9mm 增加到 60°屈曲时的 328.9±27.2mm。在膝关节 40°时，I 组和 II 组的外侧关节面接触面积有显著差异。在膝关节 20°和 40°时，I 组和 II 组的内侧关节面接触面积有显著差异。
在整个膝关节运动过程中，髌股关节外侧关节面的接触面积在膝外翻组中较大。在膝关节屈曲的早期阶段，膝内翻组的内侧髌股关节接触面积较大。下肢对线不良是髌股关节退变的重要因素。
