Department of Orthopaedic Surgery, Beijing Jishuitan Hospital, Fourth Clinical College of Peking University, Beijing, 100035, China.
Clin Orthop Relat Res. 2010 Dec;468(12):3371-6. doi: 10.1007/s11999-010-1386-5. Epub 2010 May 18.
Previous studies show the shape of the femur in developmental dislocation of the hip (DDH) becomes more abnormal with increasing subluxation. Two kinds of high dislocations associated with DDH have been observed in clinical practice, one with (Type C1) and one without (Type C2) a false acetabulum. The presence or absence of a false acetabulum in high dislocated hips is associated with different loading patterns and could influence the development and shape of the proximal femur.
QUESTIONS/PURPOSES: We therefore determined whether (1) the proximal femoral shape and dimension in Type C1 and Type C2 hips differ from each other, and (2) the femur dislocated with the same height in Types C1 and C2 hips.
We examined the following variables on 54 proximal femurs from 54 patients with high DDH (28 Type C1 hips and 26 Type C2 hips) on AP and lateral radiographs; the ML widths of the cortical and medullary canals, height of the femoral head, height of dislocation, and height of the greater trochanter. Reproducibility of the measurements was tested by two researchers with high interobserver and intraobserver agreement.
The proximal femur in Type C2 hips was narrower and stovepipe shaped, with a smaller flare index (2.7 ± 0.6), compared with Type C1 hips (3.5 ± 1.2). The proximal femur migrated an average of 18 mm more superiorly in Type C2 than in Type C1 hips.
Our data confirm distinctions in the shape of the proximal femur in the presence and absence of a false acetabulum.
Owing to the abnormal shapes, special implants of different geometries or modular stems may be needed for reconstruction Type C2 high dislocations.
既往研究表明，随着髋关节发育性脱位（DDH）的半脱位程度增加，股骨的形状变得更加异常。在临床实践中观察到两种与 DDH 相关的高位脱位，一种伴有（C1 型）假髋臼，另一种不伴有（C2 型）假髋臼。高位脱位髋关节中假髋臼的存在与否与不同的载荷模式有关，并可能影响股骨近端的发育和形状。
问题/目的：因此，我们确定了 C1 型和 C2 型髋关节中（1）股骨近端的形状和尺寸是否存在差异，以及（2）在 C1 型和 C2 型髋关节中脱位高度相同的股骨。
我们在 54 例高位 DDH 患者（28 例 C1 型髋关节和 26 例 C2 型髋关节）的前后位和侧位 X 线片上检查了以下变量：皮质和髓腔的 ML 宽度、股骨头高度、脱位高度和大转子高度。两名研究人员进行了两次测量，以检验测量的可重复性，结果显示观察者间和观察者内的一致性均较高。
与 C1 型髋关节相比，C2 型髋关节的股骨近端更窄，呈管状，喇叭口指数更小（2.7±0.6）。C2 型髋关节的股骨近端比 C1 型髋关节平均向上迁移 18mm。
我们的数据证实了在存在和不存在假髋臼的情况下，股骨近端形状存在差异。
由于形状异常，可能需要使用不同几何形状的特殊植入物或模块化柄来重建 C2 型高位脱位。
