Department of Orthopaedic Surgery, University of Utah, Salt Lake City, UT, USA.
Clin Orthop Relat Res. 2018 Jun;476(6):1253-1261. doi: 10.1007/s11999.0000000000000226.
Restoring normal femoral rotation is an important consideration when managing femur fractures. Femoral malrotation after fixation is common and several preventive techniques have been described. Use of the lesser trochanter profile is a simple method to prevent malrotation, because the profile changes with femoral rotation, but the accuracy of this method is unclear.
QUESTIONS/PURPOSES: The purposes of this study were (1) to report the rotational profiles of uninjured femora in an adult population; and (2) to determine if the lesser trochanter profile was associated with variability in femoral rotation.
One hundred fifty-five consecutive patients (72% female and 28% male) with a mean age of 32 years (range, 12-56 years) with a CT scanogram were retrospectively evaluated. Patients were included if CT scanograms had adequate cuts of the proximal and distal femur. Patients were excluded if they had prior hip/femur surgery or anatomic abnormalities of the proximal femur. CT scanogram measurements of femoral rotation were compared with the lesser trochanter profile (distance from the tip of the lesser trochanter to the medial cortex of the femur) measured on weightbearing AP radiographs. These measurements were made by a single fellowship-trained orthopaedic surgeon and repeated for intraobserver reliability testing. Presence of rotational differences based on sex and laterality was assessed and correlation of the difference in lesser trochanter profile to the difference in femoral rotation was determined using a coefficient of determination (r).
The mean femoral rotation was 10.9° (SD ± 8.8°) of anteversion. Mean right femoral rotation was 11.0° (SD ± 8.9°) and mean left femoral rotation was 10.7° (SD ± 8.7°) with a mean difference of 0.3° (95% confidence interval [CI], -1.7° to 2.3°; p = 0.76). Males had a mean rotation of 9.4°(SD ± 7.7°) and females had a mean rotation of 11.5° (SD ± 9.1°) with a mean difference of 2.1° (95% CI, -0.1° to 4.3°; p = 0.06). Mean lesser trochanter profile was 6.6 mm (SD ± 4.0 mm). Mean right lesser trochanter profile was 6.6 mm (SD ± 3.9 mm) and mean left lesser trochanter profile was 6.5 mm (SD ± 4.0 mm) with a mean difference of 0.1 mm (-0.8 mm to 1.0 mm, p = 0.86). The lesser trochanter profile varied between the sexes; males had a mean of 8.3 mm (SD ± 3.4), and females had a mean of 5.9 mm (SD ± 4.0). The mean difference between sexes was 2.5 mm (1.5-3.4 mm; p < 0.001). The magnitude of the lesser trochanter profile measurement and degree of femoral rotation were positively correlated such that increasing measures of the lesser trochanter profile were associated with increasing amounts of femoral anteversion. The lesser trochanter profile was associated with femoral version in a linear regression model (r = 0.64; p < 0.001). Thus, 64% of the difference in femoral rotation can be explained by the difference in the lesser trochanter profile. Intraobserver reliability for both the femoral version and lesser trochanter profile was noted to be excellent with intraclass correlation coefficients of 0.94 and 0.95, respectively.
This study helps define the normal femoral rotation profile among adults without femoral injury or bone deformity and demonstrated no rotational differences between sexes. The lesser trochanter profile was found to be positively associated with femoral rotation. Increasing and decreasing lesser trochanter profile measurements are associated with increasing and decreasing amounts of femoral rotation, respectively.
The lesser trochanter profile can determine the position of the femur in both anteversion and retroversion, supporting its use as a method to restore preinjury femoral rotation after fracture fixation. Although some variability in the rotation between sides may exist, matching the lesser trochanter profile between injured and uninjured femora can help reestablish native rotation.
在处理股骨骨折时，恢复正常的股骨旋转是一个重要的考虑因素。股骨固定后旋转不良很常见，已经描述了几种预防技术。使用小转子轮廓是一种预防旋转不良的简单方法，因为轮廓随股骨旋转而改变，但这种方法的准确性尚不清楚。
问题/目的：本研究的目的是：(1)报告成人中未受伤股骨的旋转情况；(2)确定小转子轮廓是否与股骨旋转的变化有关。
回顾性评估了 155 例连续患者（72%为女性，28%为男性），平均年龄为 32 岁（范围 12-56 岁）。如果 CT 扫描图有足够的股骨近端和远端的切割，患者将被纳入。如果患者有先前的髋关节/股骨手术或股骨近端解剖异常，则将患者排除在外。通过一名接受过 fellowship培训的骨科医生比较 CT 扫描股骨旋转的测量值与负重前后位 X 线片上测量的小转子轮廓（从小转子尖端到股骨内侧皮质的距离）。对观察者内可靠性进行了重复测试。评估了基于性别和侧别的旋转差异，并使用确定系数(r)确定小转子轮廓差异与股骨旋转差异之间的相关性。
平均股骨旋转为 10.9°（标准差±8.8°）的前倾角。右侧股骨平均旋转 11.0°（标准差±8.9°），左侧股骨平均旋转 10.7°（标准差±8.7°），平均差异为 0.3°（95%置信区间[-1.7°，2.3°]；p=0.76）。男性的平均旋转为 9.4°（标准差±7.7°），女性的平均旋转为 11.5°（标准差±9.1°），平均差异为 2.1°（95%置信区间[-0.1°，4.3°]；p=0.06）。小转子轮廓的平均宽度为 6.6mm（标准差±4.0mm）。右侧小转子轮廓的平均宽度为 6.6mm（标准差±3.9mm），左侧小转子轮廓的平均宽度为 6.5mm（标准差±4.0mm），平均差异为 0.1mm（-0.8mm 至 1.0mm，p=0.86）。小转子轮廓在性别之间存在差异；男性的平均宽度为 8.3mm（标准差±3.4mm），女性的平均宽度为 5.9mm（标准差±4.0mm）。男女之间的平均差异为 2.5mm（1.5-3.4mm；p<0.001）。小转子轮廓的测量值与股骨旋转的程度呈正相关，即小转子轮廓的测量值越大，股骨前倾角越大。线性回归模型显示，小转子轮廓与股骨旋转之间存在相关性（r=0.64；p<0.001）。因此，股骨旋转的差异有 64%可以用小转子轮廓的差异来解释。股骨旋转和小转子轮廓的观察者内可靠性都很好，组内相关系数分别为 0.94 和 0.95。
本研究有助于确定无股骨损伤或骨畸形的成年人的正常股骨旋转情况，并且没有发现性别之间的旋转差异。小转子轮廓与股骨旋转呈正相关。增加和减少小转子轮廓的测量值与股骨旋转量的增加和减少分别相关。
小转子轮廓可以确定骨折固定后股骨的前倾角和后倾角的位置，支持其作为一种恢复骨折固定后股骨旋转的方法。虽然两侧的旋转可能存在一定的差异，但在受伤和未受伤的股骨之间匹配小转子轮廓可以帮助重新建立原始旋转。
