Teratani Takeshi, Naito Masatoshi, Shiramizu Kei, Nakamura Yoshinari, Moriyama Shigeaki
Department of Orthopedic Surgery, Fukuoka University School of Medicine, Fukuoka, Japan.
Acta Orthop. 2008 Aug;79(4):474-82. doi: 10.1080/17453670710015454.
Medial displacement of the femoral head reduces the force transmitted across the hip joint. Since 2005, we have performed a modified Ganz's osteotomy with curved periacetabular osteotomy (CPO) to obtain medialization of the femoral head. The modification involves cutting of the pubis at 30 degrees to the horizontal line. Here, we examined whether this modified CPO procedure medialized the femoral head more than the conventional CPO procedure.
69 patients (mean age 37 years, 72 hips) treated with the modified CPO procedure (the M group) were compared with 68 patients (mean age 38 years, 72 hips) previously treated with conventional CPO (the C group). All patients were operated because of dysplastic hips. We used radiographic measurements from anteroposterior radiographs. The magnitude of the resultant hip force normalized with respect to the body weight (R/WB) and hip contact joint stress (Pmax/ WB) was calculated in all cases.
The average lateral center-edge (CE) angle, acetabular roof obliquity (ARO), and acetabulum-head index (AHI) improved in both groups. The CE angle, ARO, and AHI were similar in the 2 groups before and after surgery. Medialization of the femoral head was larger in the M group than in the C group (p < 0.001). The average value of the resultant hip force decreased from 3.2 to 2.9 in the M group and remained unchanged, at 3.1, in the C group. In addition, the average value of the peak contact stress decreased more in the M group (from 9.4 kPa/N to 3.4 kPa/N) than in the C group (from 9.1 kPa/N to 4.3 kPa/N).
In dysplastic hips, the modified CPO reduces the contact hip stress more than the conventional CPO because of better medialization of the femoral head.
股骨头内移可减少通过髋关节传递的力量。自2005年以来，我们采用改良的甘茨截骨术联合髋臼周围弧形截骨术（CPO）来实现股骨头内移。改良之处在于耻骨截骨线与水平线呈30度角。在此，我们研究了这种改良的CPO手术是否比传统CPO手术能使股骨头内移更多。
将69例接受改良CPO手术的患者（平均年龄37岁，72髋）（M组）与68例先前接受传统CPO手术的患者（平均年龄38岁，72髋）（C组）进行比较。所有患者均因髋关节发育不良接受手术。我们使用前后位X线片进行影像学测量。计算所有病例中相对于体重归一化的合成髋关节力大小（R/WB）和髋关节接触关节应力（Pmax/WB）。
两组的平均外侧中心边缘（CE）角、髋臼顶倾斜度（ARO）和髋臼-股骨头指数（AHI）均有所改善。两组手术前后的CE角、ARO和AHI相似。M组股骨头内移程度大于C组（p < 0.001）。M组合成髋关节力的平均值从3.2降至2.9，而C组保持不变，为3.1。此外，M组峰值接触应力的平均值下降幅度（从9.4 kPa/N降至3.4 kPa/N）大于C组（从9.1 kPa/N降至4.3 kPa/N）。
在髋关节发育不良中，改良的CPO由于能更好地使股骨头内移，比传统CPO更能降低髋关节接触应力。
