三维CT评价骨盆内移截骨后青少年髋臼发育不良的效应

Effect of Chiari’s osteotomy for adolescents with acetabular dysplasia evaluated by three-dimensional CT

背景：通过传统的X射线评价,Chiari截骨能明显改善股骨头的覆盖,但对截骨后效果的三维立体评价研究很少。目的：利用三维CT评价Chiari截骨术后髋关节的形态变化,同时比较X射线及三维CT方法测量股骨头覆盖是否存在差异。设计、时间及地点：测量性试验,病例来自2003-01/2006-12中国医科大学附属盛京医院小儿骨科。对象：选择中国医科大学附属盛京医院小儿骨科收治的髋臼发育不良患儿12例（12髋）,男5例,女7例;左侧8例,右侧4例;手术时年龄7.2～15.2岁,平均11.5岁。方法：12例患者（12髋）均行Chiari截骨治疗。5髋在关节囊外截骨，7髋行关节囊小切口紧邻髋臼外上缘截骨。根据Colton提出的评分方法进行临床功能评价；在前后位X射线平片测量手术前、后的股骨头覆盖率及截骨的高度；在三维CT图像上测量股骨头前1／4、中1，2、后1/4部位的覆盖率。主要观察指标：X射线测量截骨前后股骨头覆盖率、截骨高度；三维CT测量冠状面上股骨头前1／4、中1／2、后1／4的覆盖率及髋臼前倾角；Colton法测量髋关节的功能评分。结果：所有12髋术后临床功能评定，优6髋，良3髋，3髋为一般；在切开关节囊的7髋中，优2髋，良3髋，未行关节囊切开的5髋中，优良各2髋；在切开关节囊的髋中，截骨高度低于未行关节囊切开髋中的截骨高度[（3．64±1．54），（11．00±2．09）mm，P〈0．01]；不同截骨高度与临床评定结果之间差异无显著性意义（P〉0．05）。术前9例有明显的髋痛，随访时，5例已无疼痛（其中4髋截骨高度适宜），4髋截骨过高者仍有疼痛；无深部感染、坐骨神经损伤、骨不连等严重并发症发生。术后，X射线及三维CT测得的股骨头覆盖率较术前均明显增加（P〈0．01）；但三维CT测得的股骨头前外侧、中外侧覆盖率明显小于X射线测量结果（P〈0．01）；术后在股骨头的前外侧仍存在覆盖不良。结论：利用X射线测量评价Chiari截骨术后股骨头的覆盖存在假像，真实情况并非像X射线测量结果那样完美。术前、术后利用三维CT仔细评价髋关节的病理缺陷是必要的。Chiari截骨后，在股骨头前外侧仍覆盖不良。为达到合适的截骨高度，行关节囊小切口准确显示髋臼的外上缘对术后关节活动无明显影响。

BACKGROUND： Traditional radiographic evaluation has demonstrated that the Chiari＇s osteotomy can provlde a sufficient osseous cover over the femoral head. However, there are few studies on three-dimensional evaluation following Chiari＇s osteotomy. OBJECTIVE： To evaluate the morphological changes of the hips after Chian＇s osteotomy, and to compare the difference of the femoral head coverage measured by three-dimension computed tomography （3D-CT） and radiographic findings. DESIGN, TIME AND SETTING： Measurement. The patients included in this study were selected from the Department of Pediatric Orthopaedics, Shengjing Hospital of China Medical University between January 2003 and December 2006. PARTICIPANTS： A total of 12 patients （12 hips） with acetabular dysplasia were selected, including 7 females and 5 males; 8 cases of the left and 4 cases of the right. The average age at operation was 11.5 years （ranging 7.2-15.2 years）. METHODS： All the patients were treated by Chiari＇s osteotomy. In 5 hips, an extra-articular osteotomy was performed. In the remaining hips, a minimal opening was made into the anterosuperiorjoint capsule for locating the acetabular edge accurately. The clinical function was evaluated using Colton scoring method. The femoral head coverage （anterior 1/4, middle 1/2, and posterior 1/4） and osteotomy height were measured by X-ray method. MAIN OUTCOME MEASURES： The anterolateral, mediolateral and posterolateral femoral head coverage and acetabular anteversion angle were evaluated by 3D-CT method. Colton＇s score system was used to assess the clinical function of the hip. RESULTS： In the clinical function evaluation of 12 hips, 6 hips were excellent, 3 were good and 3 were general. Of the 7 hips undergoing joint capsule opening, 2 were excellent and 3 were good; of the 5 hips without joint capsule opening, 2 were excellent and 2 were good. The average osteotomy height was lower in the intra-articular osteotomy group than in the extra-articular osteotomy group [（3.64±1.54）, （11.00±2.09） mm, P〈 0.01]. No correlation was found between the osteotomy height and the clinical results （P〉 0.05）. Nine cases had obvious hip pain preoperatively, and 5 were relieved during the follow-up （the height of 4 hips was appropriate）, but 4 still felt pain. No deep infection, injury of sciatic nerve, or bone nonunion occurred. The postoperative 3D-CT and radiological measurements showed a significant improvement in the femoral head coverage （P 〈 0.01 ）. However, the coverage measured by 3D-CT on the anterolateral and mediotateral coronal plane was significantly smaller than that measured by radiography （P 〈 0.01 ）. The postoperative 3D-CT demonstrated the femoral head coverage was still insufficient in the anterolateral and mediolateral part. CONCLUSION： Conventional radiographs may show sufficient cover of the femoral head whereas in fact the cover is insufficient. After Chiari＇s osteotomy, the anterior cover of femoral head is still insufficient. A minimal opening into the capsule is recommended to obtain a proper osteotomy height, which does not affect joint activity postoperatively.