髋关节置换股骨偏心距和下肢长度重建方法

Reconstruction of femoral offset and lower extremity length for hip arthroplasty

背景:人工髋关节置换股骨偏心距和下肢长度的重建直接影响患者术后功能的恢复和假体的使用寿命,目前多采用术前模板测量来预测股骨假体的型号及置入位置,估计股骨颈的截骨水平,但是测量比较繁琐,欠精确。目的:设计通过股骨头假体长度和股骨颈截骨平面的选择来重建股骨偏心距和下肢长度的计算方法。设计、时间及地点:探索性实验,于2008-08/2009-02在单县中心医院完成。对象:选择单县中心医院接受髋关节置换的22例股骨颈骨折和股骨头缺血坏死患者。方法:术前测算健侧股骨偏心距E和髋关节旋转中心至小转子最高点的垂直距离D(下肢内旋15°)。设股骨假体偏心距为E′,垂降为H。设股骨颈截骨平面最下缘距小转子最高点的垂直距离为h,标准股骨头假体+0,其余为+L。股骨假体颈干角的补角为A。通过数学方法推导髋关节置换股骨偏心距和下肢长度重建股骨头长度及股骨颈截骨平面选择的计算公式。主要观察指标:股骨偏心距、髋关节旋转中心至小转子最高点的垂直距离、股骨假体偏心距、股骨假体颈干角、股骨假体垂降。结果:①E=E′+LsinA。②D=h+H+LcosA。结论:成功推导出髋关节置换股骨偏心距和下肢长度重建股骨头长度及股骨颈截骨平面选择的计算公式,该公式简单准确。

BACKGROUND： Reconstruction of femoral eccentricity and lower extremity length in artificial hip arthroplasty directly influences useful life of prosthesis and functional recovery of patients. Currently, preoperative measurement is frequently used to predict femoral prosthesis type and insertion location or to evaluate osteotomy level of femoral neck, but this method is tedious and not accurate. OBJECTIVE： To design computing methods to reconstruct femoral offset and lower extremity length by selecting artificial femoral head length and osteotomy plane of femoral neck. DESIGN, TIME AND SETTING： Exploration experiment was performed at Shanxian Central Hospital from August 2008 to February 2009. PARTICIPANTS： A total of 22 patients with femoral neck fracture and ischemic necrosis of femoral head, who underwent hip arthroplasty in Shanxian Central Hospital were selected. METHODS： The contralateral femoral offset E and the vertical distance D from hip joint rotational center to the highest point of small trochanter （lower limb internal rotation 15°） were measured preoperatively. Femoral prosthesis medial offset was assumed as E′, vertical height as H, the vertical distance from the lowest edge of femoral neck osteotomy plane to the highest point of small trochanter as h, the standard femoral head prosthesis as ＋0, the remaining as ＋L, and the supplementary angle of femoral neck-stem angle as A. The calculating formula for the selection of the femoral head length and femoral neck osteotomy plane used for reconstructing femoral offset and lower extremity length during hip arthroplasty was determined by mathematical method. MAIN OUTCOME MEASURES： Femoral offset, vertical distance from the hip joint rotational center to the highest point of small trochanter, femoral prosthesis medial offset, femoral neck-stem angle and femoral prosthesis vertical distance from the lowest edge of femoral neck osteotomy plane to the highest point of small trochanter. RESULTS：①E = E′＋ LsinA, ②D = h ＋ H ＋ LcosA. CONCLUSION： The formula for the selection of the femoral head length and femoral neck osteotomy plane used for reconstructing femoral offset and lower extremity length during hip arthroplasty was successfully deducted, and it is simple and accurate.