INTRODUCTION Sarcopenia is defined as a progressive loss of muscle mass and function with increased age. The measurement of muscle mass and attenuation on the axial computed tomography (CT) scan has been reported to be a good indicator for sarcopenia in previous literature. This study aimed to compare muscle mass between the intertrochanteric fracture and femoral neck fracture groups by accurately measuring muscle mass around the hip joint using a CT scan. METHODS The cases were matched according to age and gender on a 1-to-1 basis. As a result, a total of 400 patients, 200 patients in each group with the same age and gender characteristics, were included in the study. At the disc of L4-L5 level, the cross-sectional area (CSA) of the psoas muscle was evaluated, and at the disc of L5-S1 level, the CSA of the psoas, iliacus and gluteus medius muscles were evaluated. In addition, attenuation was evaluated using the average Hounsfield Unit (HU) for the specific area. RESULTS The mean age of 400 patients (262 females, 138 male) included in the study was 78.49 ± 7.67 years. It was observed that the mean HU values of the patients in the femoral neck fracture group were significantly higher than the intertrochanteric fracture group (p < 0.001, p = 0.008; respectively). At the same time, the mean HU values of the gluteus medius muscle were higher in the femoral neck fracture group (p < 0.001), but in contrast with the psoas muscle, the CSA values of gluteus medius muscle were significantly higher in the intertrochanteric fracture group (p = 0.017). CONCLUSIONS Fatty degeneration of the psoas muscle among the muscles around the hip may affect the type of hip fracture. Elderly patients with strong psoas muscles may experience femoral neck fracture due to contraction and torsion during falling.

中文翻译：

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腰肌和臀中肌衰减对髋部骨折类型的影响。

简介 肌肉减少症被定义为随着年龄的增长肌肉质量和功能逐渐丧失。先前的文献报道，轴向计算机断层扫描（CT）扫描的肌肉质量和衰减测量是肌肉减少症的良好指标。本研究旨在通过 CT 扫描准确测量髋关节周围的肌肉质量，比较股骨粗隆间骨折组和股骨颈骨折组之间的肌肉质量。方法将病例按照年龄、性别进行1对1匹配。结果，共有400名患者纳入研究，每组200名具有相同年龄和性别特征的患者。在L4-L5水平的椎间盘处评估腰肌的横截面积（CSA），在L5-S1水平的椎间盘处评估腰肌、髂肌和臀中肌的CSA。此外，还使用特定区域的平均亨斯菲尔德单位 (HU) 来评估衰减。结果 该研究纳入的 400 名患者（262 名女性，138 名男性）的平均年龄为 78.49 ± 7.67 岁。结果发现，股骨颈骨折组患者的平均 HU 值显着高于股骨粗隆间骨折组（分别为 p < 0.001、p = 0.008）。同时，股骨颈骨折组臀中肌的平均 HU 值较高（p < 0.001），但与腰肌相比，股骨粗隆间骨折组臀中肌的 CSA 值显着较高组（p = 0.017）。结论 髋部周围肌肉中腰肌的脂肪变性可能影响髋部骨折的类型。腰肌强壮的老年患者，跌倒时可能会因收缩和扭转而发生股骨颈骨折。