Hoelsbrekken Sigurd Erik, Dolatowski Filip C
Department of Orthopedic and Rheumatic Surgery, Kongsvinger Hospital, P.O. Box 901, 2226, Kongsvinger, Norway.
Institute of Clinical Medicine, University of Oslo, Norway; Department of Orthopedics, Akershus University Hospital, N-1478Lørenskog, Norway.
Injury. 2017 Oct;48(10):2184-2188. doi: 10.1016/j.injury.2017.08.053. Epub 2017 Aug 26.
Lateral radiographs are important for the evaluation of Garden I and II femoral neck fractures. These fractures appear undisplaced in the anteroposterior view, but posterior tilt of the femoral head may still be present in the lateral view. The influence of posterior tilt is, however, debated, which could be caused by the use of non-standardized cross-table radiographs in the conflicting reports. The aim of this bone-model study was therefore to evaluate the influence of the hips position on measurements of posterior tilt.
We generated models of a Garden I-II femoral neck fracture and the non-injured contralateral femur from CT reconstructions with a 3D-printer. Lateral radiographs of the models were obtained in positions ranging from 90° internal rotation (IR) to 90° external rotation (ER) and 0-80° flexion. Two investigators independently measured posterior tilt on 27 lateral radiographs obtained from each model.
The inter-tester ICC was 0.91 (0.84-0.94), standard error of measurement (SEM) 2.6, and minimal detectable change (MDC) 7.2. The median (range) posterior tilt for the fracture model was 21.9° (5.0, 33.8) and 23.6° (2.2, 28.6) for observer 1 and observer 2, respectively. The corresponding posterior tilt within the range of 10° IR to 40° ER and 0 to 30° flexion of the fracture model, was 27.3° (24.0, 33.8) and 26.3° (24.8, 28.6).
The range of posterior tilt measurements for positions of the proximal femur restricted from 10° IR to 40° ER and 0 to 30° flexion, was above the MDC for observer 1, and below the MDC for observer 2. These findings indicate that rotation and flexion affect measurements of posterior tilt, but the influence may be negligible for positions of the injured extremity that are clinically relevant during cross-table lateral radiographs. A larger study that accounts for variations in anatomy and fracture displacement is required to confirm these findings.
侧位X线片对于评估Garden I型和II型股骨颈骨折很重要。这些骨折在前后位片上看似无移位，但在侧位片上股骨头仍可能存在后倾。然而，后倾的影响存在争议，这可能是由于在相互矛盾的报告中使用了非标准化的交叉台面X线片。因此，本骨模型研究的目的是评估髋关节位置对后倾测量的影响。
我们使用3D打印机根据CT重建生成了Garden I-II型股骨颈骨折模型和未受伤的对侧股骨模型。在从90°内旋（IR）到90°外旋（ER）以及0-80°屈曲的位置获取模型的侧位X线片。两名研究人员独立测量了从每个模型获得的27张侧位X线片上的后倾情况。
测试者间的组内相关系数（ICC）为0.91（0.84-0.94），测量标准误差（SEM）为2.6，最小可检测变化（MDC）为7.2。骨折模型的后倾中位数（范围），观察者1为21.9°（5.0，33.8），观察者2为23.6°（2.2，28.6）。骨折模型在10°内旋至40°外旋以及0至30°屈曲范围内的相应后倾，观察者1为27.3°（24.0，33.8），观察者2为26.3°（24.8，28.6）。
股骨近端位置限制在10°内旋至40°外旋以及0至30°屈曲时的后倾测量范围，对于观察者1高于MDC，对于观察者2低于MDC。这些发现表明旋转和屈曲会影响后倾测量，但对于交叉台面侧位X线片检查期间临床上相关的受伤肢体位置，其影响可能可忽略不计。需要进行一项考虑解剖结构和骨折移位变化的更大规模研究来证实这些发现。
