3D打印股骨近端弧形柄仿生假体重建股骨中上段超极限骨缺损保髋治疗的中期临床疗效

Mid-term effectiveness of hip preservation in the reconstruction of ultrashort bone segments in the proximal femur with three-dimensional printed customized cementless intercalary endoprosthesis with an intra-neck curved stem

目的探索3D打印股骨近端弧形柄仿生假体的设计要点,评估将其应用于重建股骨中上段超极限骨缺损的手术要点和中期临床疗效。方法2015年10月—2021年1月,17例患者接受了3D打印股骨干弧形柄仿生假体重建。男11例,女6例;年龄10~76岁,平均30.1岁。骨肉瘤9例,尤文肉瘤4例,软骨肉瘤2例,脂肪肉瘤1例,肌纤维母细胞瘤1例。病程5~14个月,平均9.5个月。Enneking分期:ⅡB期16例,ⅢB期1例。根据X线片测量术前股骨头中心到人体正中线和髋臼顶点的距离,术后即刻及末次随访时弧形柄尖端到人体正中线和髋臼顶点的距离,以及术前、术后即刻和末次随访时的颈干角。通过X线片、CT和断层融合成像技术(Tomosynthesis-Shimadzu metal artefact reduction technology,T-SMART)评估骨-假体界面的骨整合状况及假体表面骨长入情况。随访患者生存状态、有无局部复发或远处转移,术后并发症发生情况。手术前后通过肌肉骨骼肿瘤学会(MSTS)评分评价下肢功能恢复情况,疼痛视觉模拟评分(VAS)评价疼痛缓解情况。结果患者股骨切除长度为(163.1±57.5)mm,剩余股骨近端长度为(69.6±9.3)mm,股骨切除长度/股骨总长度百分比为38.7%±14.6%。17例患者均获随访,随访时间25~86个月,平均58.1个月。随访期间1例患者于术后46个月死于肺转移,余16例患者无瘤生存。均未发生假体周围感染、切口延迟愈合、假体无菌性松动、假体断裂、假体周围骨折等并发症。X线片和T-SMART评估未发现植入假体柄周围微动磨损,也无明显放射性透亮带,并且在所有柄中都发现了骨-假体界面上骨向内生长的射线学迹象。术后即刻及末次随访时弧形柄尖端到人体正中线和髋臼顶点的距离分别与术前股骨头中心到人体正中线和髋臼顶点的距离比较,差异无统计学意义(P>0.05);术后即刻和末次随访间上述指标比较差异亦无统计学意义(P>0.05)。手术前后各时间点颈干角比较差异均无统计学意义(P>0.05)。末次随访时患者MSTS评分为(26.1±1.2)分,VAS评分为(0.1±0.5)分,均较术前[分别为(19.4±2.1)分和(5.7±1.0)分]显著改善(t=14.735,P<0.001;t=21.301,P<0.001)。末次随访时,患者均无需借助拐杖或其他助行器行走。结论3D打印股骨近端弧形柄仿生假体是股骨中上段恶性肿瘤切除术后超极限骨缺损重建的有效方法,术中操作可靠,术后下肢功能恢复满意,并发症发生率低。

Objective To explore the design points of a three-dimensional(3D)printed customized cementless intercalary endoprosthesis with an intra-neck curved stem and to evaluate the key points and mid-term effectiveness of its application in the reconstruction of ultrashort bone segments in the proximal femur.Methods Between October 2015 and January 2021,17 patients underwent reconstruction with a 3D printed-customized cementless intercalary endoprosthesis with an intra-neck curved stem.There were 11 males and 6 females,the age ranged from 10 to 76 years,with an average of 30.1 years.There were 9 cases of osteosarcoma,4 cases of Ewing sarcoma,2 cases of chondrosarcoma,1 case of liposarcoma,and 1 case of myofibroblastoma.The disease duration was 5-14 months,with an average of 9.5 months.Enneking staging included 16 cases of stageⅡB and 1 case of stageⅢB.The distances from the center of the femoral head to the body midline and the acetabular apex were measured preoperatively on X-ray images.Additionally,the distances from the tip of the intra-neck curved stem to the body midline and the acetabular apex were measured at immediate postoperatively and last follow-up.The neck-shaft angle was also measured preoperatively,at immediate postoperatively,and at last follow-up.The status of osseointegration at the bone-prosthesis interface and bone growth into the prosthesis surface were assessed by X-ray films,CT,and Tomosynthesis-Shimadzu metal artefact reduction technology(T-SMART).The survival status of the patients,presence of local recurrence or distant metastasis,and occurrence of postoperative complications were assessed.The recovery of lower limb function was evaluated pre-and post-operatively using the Musculoskeletal Tumor Society(MSTS)scoring system,and pain relief was evaluated using the visual analogue scale(VAS)scores.Results The patient’s femoral resection length was(163.1±57.5)mm,the remaining proximal femoral length was(69.6±9.3)mm,and the percentage of femoral resection length/total femoral length was 38.7%±14.6%.All 17 patients were followed up 25-86 months with an average of 58.1 months.During the follow-up,1 patient died of lung metastasis at 46 months postoperatively,and the remaining 16 patients survived tumor-free.There was no complication such as periprosthetic infection,delayed incision healing,aseptic loosening,prosthesis fracture,or periprosthetic fracture.No evidence of micromotion or wear around the implanted stem of the prosthesis was detected in X-ray and T-SMART evaluations.There was no significant radiolucent lines,and radiographic evidence of bone ingrowth into the bone-prosthesis interface was observed in all stems.There was no significant difference in the distance from the tip of the curved stem to the body midline and the apex of the acetabulum at immediate postoperatively and last follow-up compared with the distance from the center of the femoral head to the body midline and the apex of the acetabulum before operation,respectively(P>0.05),and there was no significant difference in the above indexes between immediate postoperatively and last follow-up(P>0.05).The differences in the neck-shaft angle at various time points before and after operation were also not significant(P>0.05).At last follow-up,the MSTS score was 26.1±1.2 and the VAS score was 0.1±0.5,which were significantly improved when compared with those before operation[19.4±2.1 and 5.7±1.0,respectively](t=14.735,P<0.001;t=21.301,P<0.001).At last follow-up,none of the patients walked with the aid of crutches or other walkers.Conclusion The 3D printed customized cementless intercalary endoprosthesis with an intra-neck curved stem is an effective method for reconstructing ultrashort bone segments in the proximal femur following malignant tumor resection.The operation is reliable,the postoperative lower limb function is satisfactory,and the incidence of complications is low.