采用锥形股骨柄生物学固定对高龄患者行全髋置换术后的骨改建及临床疗效

目的 探讨采用锥形股骨柄假体生物学固定对高龄患者行全髋关节置换术(total hip arthroplsty,THA)后的假体周围骨改建及中期临床疗效.方法 随机选取2003年1月-2005年1月采用锥形股骨柄假体生物学固定行THA的高龄患者(70～90岁)30例(34髋).对术后及随访X线片的影像学资料、术后及随访中采用双能X线骨密度仪(DEXA)测量的手术前、后假体周围骨密度资料进行分析,临床疗效采用Harris标准评定,并以Kaplan-Meier法评价股骨假体的使用寿命.结果 4例死于肺癌,余26例(30髋)获5～7年(平均6年)随访.术后X线片测量显示12髋1年内假体下沉＜1.5 mm,无假体松动.增生性骨反应见于Gruen 2,3,4,5,6,11,12区;吸收性骨反应见于1,7区.DEXA检查显示骨密度增加在2,3,4,5区,骨密度减少主要发生在1,6,7区.术后6个月内,2,5区的骨密度增加速度最快(P＜0.05),2年后各区骨密度改变趋于稳定(P＞0.05).术后1年内的假体周围总骨密度减少较多(P＜0.05),手术2年后的假体周围总骨密度基本无改变(P＞0.05),只是骨量从股骨近端到远端呈区域性重新分布.髋关节功能Harris评分从术前38.56±8.21提高至最近随访时的86.32±6.01,假体6年存留率达100%.结论采用锥形股骨柄假体生物学固定对高龄患者行THA后的假体周围具有良好的骨改建模式,且中期临床效果良好.

Clinical results of femoral shaft remodeling with tapered stems after total hip arthroplasty in the elderly patients

Objective To investigate periprosthetic femoral shaft remodeling with tapered femoral stems after total hip arthroplasty (THA) for elderly patients and evaluate the mid-term clinical outcomes.Methods The study involved 30 elderly (70-90 years) patients (34 hips) treated with femoral shaft remodeling with tapered stems after THA from January 2003 to January 2005. The postoperative X-ray images were collected and perioperative periprosthetic bone mineral density was analyzed by dual-energy X-ray absorptiometry (DEXA). The Harris score was applied in follow-up observation, and Kaplan-Meier method was used to evaluate the working life of the femoral prosthesis. Results Four patients were died of lung cancer. The remaining 26 patients ( 30 hips) were followed up for 5-7 years ( mean, six years). The postoperative X-ray measurements showed that total hip prosthesis subsidences were less than 1.5 mm within one year in 12 hips, with no prosthesis loosening observed. Bone proliferations were seen in Gruen zones 2, 3, 4, 5, 6, 11 and 12, and bone resorptions were seen in zones l and 7. DEXA showed that bone mineral density was increased in Gruen zones 2,3,4 and 5, but decreased mainly in Gruen zones 1,6 and 7. The increase of bone mineral density in zones 2 and 5 was faster compared to other sites six months after the operation ( P ＜ 0.05 ) and the change of bone mineral density was prone to be stable in two years ( P ＞ 0.05 ). Within one year after initial implantation, periprosthetic bone mineral density was significantly decreased ( P ＜ 0.05 ). Two years after the operation, rare changes of periprosthetic bone mineral density were found ( P ＞ 0.05 ), with only regional redistribution of bone mass from the proximal to the distal femur. The Harris score of hip joint function was increased from preoperative 38.56 ± 8.21 to 86.32 ± 6. 01 at the final follow-up. The 6-year survival rate of the prosthesis was 100%. Conclusion Femoral shaft remodeling with tapered stems after total hip arthroplasty for the elderly patients shows good periprosthetic bone remodeling and satisfactory mid-term clinical results.