Three-Dimensional Reconstruction Modeling of the Spatial Displacement, Extent and Rotational Orientation of Undisplaced Femoral Neck Fractures.

The purpose of this study was to employ a new three-dimensional (3D) reconstruction and modeling method to measure displacement of undisplaced femoral neck fractures (Garden stages I and II). We also aimed to evaluate the effectiveness of the Garden classification for determining the displacement of undisplaced femoral neck fractures. A total of 120 consecutive patients with undisplaced femoral neck fractures were enrolled between 2012 and 2014, including 60 within the Garden I group and 60 within the Garden II group. The displacements of the femoral head center (d1) and the lowest point of the fovea capitis femoris (d2) and rotational displacement of the femoral head (α) in the 3D model were measured with 3D computed tomography reconstruction and modeling. Five observers, trauma surgeons, were asked to found the centers of the femoral heads and the deepest points of the foveae. The intraobserver and inter-observer agreements were calculated using Fleiss' kappa. The inter-observer and intra-observer kappa values were 0.937 and 0.985, respectively. Current method has good reliability. We discovered that many participants in our study had been misclassified by an anterior-posterior radiograph as having an "incomplete" fracture. In incomplete fracture of Garden stage I group, the average displacements d1 and d2 were 3.69 ± 1.77 mm and 14.51 ± 1.91 mm, respectively. The mean α was 4.91° ± 2.49°. For impacted fracture of Garden stage I, significant spatial displacement in the impacted fractures was observed (d1: 6.22 ± 3.36 mm; d2: 10.30 ± 5.73 mm; and α: 17.83° ± 10.72°). Similarly, significant spatial displacement was observed among the Garden stage II group (d1: 7.16 ± 4.58 mm; d2: 12.95 ± 8.25 mm; and α: 18.77° ± 9.10°). There was no significant difference in α, d1, and d2 between impacted fracture and Garden stage II groups (P > 0.05). However, significant differences were found between incomplete fracture and Garden stage II groups (P < 0.05). Our findings suggest that 3D reconstruction and modeling may be a better tool for assessing femoral neck fractures than the Garden classification. Undisplaced femoral neck fractures showed variable degrees of displacement and were not undisplaced, stable fractures. Garden classification for undisplaced femoral neck fractures has certain limitations.

Reunderstanding of garden type I femoral neck fractures by 3-dimensional reconstruction.

Garden type I fractures include incomplete fractures and impacted fractures. With advances in scientific technology and medical treatment, certain deficiencies of the Garden classification have become apparent. The authors hypothesized that the incidence of incomplete femoral neck fractures was low and that impacted femoral neck fractures were not undisplaced and stable fractures. A new method was developed to precisely measure the spatial displacement of the femoral head in impacted femoral neck fractures. Between 2008 and 2011, nine hundred sixty-six patients with femoral neck fractures were treated, 48 of whom had Garden type I fractures, as seen on anteroposterior radiographs. Seven fractures were classified as incomplete on radiographs; however, after 3-dimensional reconstruction, 3 were classified as incomplete and 4 as complete fractures. Furthermore, the remaining 41 Garden I fractures that were classified as impacted on radiographs showed large spatial displacement on 3-dimensional reconstruction. The average rotational displacement of the femoral head was 19.29°±10.51°, and the average displacements of the femoral head center and the lowest point of the fovea capitis were 8.76±4.45 and 14.39±8.08 mm, respectively. This study showed that the incidence of incomplete femoral neck fractures was low. Impacted femoral neck fractures showed variable degrees of displacement and were not undisplaced, stable fractures. Garden classification for impacted femoral neck fractures has certain limitations. Impacted femoral neck fractures should be differentiated from Garden type I fractures so clinicians can select appropriate treatments for these fractures.

[Three-dimensional reconstruction study of the displacement of undisplaced femoral neck fractures].

OBJECTIVE: To measure the displacement parameters of femoral head in space through three-dimensional reconstruction so as to reunderstand undisplaced femoral neck fractures. METHODS: The clinical data of 80 undisplaced femoral neck fractures from January 2010 to June 2011 were selected, included Garden I 40 cases (group Garden I) and Garden II 40 cases (group Garden II), bilateral proximal femurs of everyone were scanned by CT and reconstructed by professional software. Registered the normal femur and fracture with mirror model, marked key points in the model and measured the displacement parameters of femoral head. The measurement accuracy of distance and angle were 0.01 mm and 0.01°, respectively. The parameters of femoral head displacement between group Garden I and Garden II were analyzed by independent-sample t-test. RESULTS: Eighty cases on X-ray films were not found rotated displacement. But 24 cases of them (30.0%) showed rotated displacement and rotation direction of the femoral head through three-dimensional reconstruction. Ten cases showed incomplete fractures on X-ray films, but only 3 cases were incomplete fractures with three-dimensional reconstruction. In group Garden I, the femoral head displacement angle was 18° ± 11°, the average displacement distance of femoral head center and deepest point of fovea capitis were (6 ± 3) mm and (10 ± 6) mm respectively. In group Garden II, the femoral head displacement angle was 17° ± 10°, the average displacement distance of femoral head center and deepest point of fovea capitis were (7 ± 5) mm and (13 ± 8) mm respectively. There were not statistical significance of the parameters of femoral head displacement between group Garden I and Garden II (P > 0.05). CONCLUSIONS: Three-dimensional reconstruction and digital measurement is a precise, efficient method for the measurement of femoral head displacement parameters in femoral neck fractures, has important clinical significance in the diagnosis and treatment of the femoral neck fractures. There are certain defects and limitations of the classical Garden classification for undisplaced femoral neck fractures.