Spine Care Center, Wakayama Medical University Kihoku Hospital, Wakayama, Japan.
Department of Orthopaedic Surgery, Saiseika Hospital, Wakayama, Japan.
J Orthop Sci. 2021 Nov;26(6):986-991. doi: 10.1016/j.jos.2020.10.014. Epub 2020 Dec 5.
The impact of sagittal imbalance in patients has been reported in LBP and LBP-related disabilities due to spinopelvic imbalance. However, no reports investigating the spine-pelvis-lower extremity axis using lateral images have been reported thus far. This study introduced a novel parameter of the spine-pelvis-lower extremity axis and evaluated whether this parameter was related to symptoms.
A total of 343 subjects were included in this cross-sectional study. Standing spine-pelvis and pelvis-lower extremity radiographs were obtained to assess the sagittal vertical axis (SVA), pelvic tilt (PT), pelvic incidence (PI), sacral slope (SS), lumbar lordosis, and thoracic kyphosis. The sacral-knee distance (SKD) (i.e., distance from the anterior femoral condyle to the vertical axis at the upper posterior edge of S1 body) was measured. Furthermore, the SVA/SKD ratio was calculated for global balance. Subjects were divided into leg compensated (LC; SVA/SKD ratio <0.8) and decompensated (LD; SVA/SKD ratio ≥0.8) groups. The SVA was divided into balanced spine (BS; SVA ≤40 mm) and imbalanced spine (IS; SVA >40 mm) groups. All individuals were classified into LC + BS, LC + IS, LD + BS, and LD + IS groups. The relationships among the four groups and low back pain (LBP), Oswestry Disability Index (ODI), and knee pain were examined.
SKD was significantly correlated with SVA, SS, PI, PT, and knee-femoral angle. ODI was significantly higher in the LC + IS group than in the LD + BS group (p < 0.05). Knee pain prevalence was significantly higher in the LC + IS and LC + BS groups than in the LD + IS group (p < 0.05).
SVA/SKD ratio is useful for evaluating global alignment. Our findings are significant because they highlight the importance of SKD with respect to knee pain, LBP, and LBP- related disabilities.
由于脊柱骨盆失衡，脊柱失衡已在腰痛（LBP）和与腰痛相关的残疾中对患者产生影响。然而，迄今为止，尚无使用侧位图像研究脊柱骨盆下肢轴的报道。本研究引入了脊柱骨盆下肢轴的新参数，并评估了该参数是否与症状相关。
本研究共纳入 343 例受试者，行站立位脊柱骨盆位及骨盆双下肢位 X 线片，以评估矢状垂直轴（SVA）、骨盆倾斜（PT）、骨盆入射角（PI）、骶骨倾斜角（SS）、腰椎前凸角和胸腰椎后凸角。测量股骨前髁至 S1 体上后缘垂线的距离（即骶膝距（SKD））。此外，计算 SVA/SKD 比值以评估整体平衡。将受试者分为下肢代偿组（LC；SVA/SKD 比值＜0.8）和失代偿组（LD；SVA/SKD 比值≥0.8）。根据 SVA 将 SVA 分为平衡脊柱组（BS；SVA≤40mm）和失平衡脊柱组（IS；SVA＞40mm）。所有个体均被分为 LC+BS、LC+IS、LD+BS 和 LD+IS 四组。分析四组与腰痛（LBP）、Oswestry 功能障碍指数（ODI）和膝关节疼痛之间的关系。
SKD 与 SVA、SS、PI、PT 和膝关节-股骨角显著相关。LC+IS 组的 ODI 明显高于 LD+BS 组（p＜0.05）。LC+IS 组和 LC+BS 组的膝关节疼痛发生率明显高于 LD+IS 组（p＜0.05）。
SVA/SKD 比值可用于评估整体的脊柱骨盆下肢轴的对齐情况。本研究的结果具有重要意义，因为它们强调了 SKD 与膝关节疼痛、腰痛和腰痛相关残疾的重要性。
