BACKGROUND Proximal femur reconstruction after bone tumor resection in children is a demanding surgery for orthopaedic oncologists because of the small bone size and possible limb-length discrepancy at the end of skeletal growth owing to physis loss. The most commonly used reconstruction types used for the proximal femur are modular prostheses and allograft-prosthesis composites. To our knowledge, there are no previous studies comparing the outcomes after modular prosthesis and allograft-prosthesis composite reconstruction of the proximal femur in children with primary bone tumors. QUESTIONS/PURPOSES (1) What was the cumulative incidence of reoperation for any reason after allograft-prosthesis composite and modular prosthesis reconstructions of the proximal femur in children with primary bone tumors? (2) What was the cumulative incidence of reconstruction removal or revision arthroplasty in those two treatment groups? (3) What complications occurred in those two treatment groups that were managed without further surgery or with surgery without reconstruction removal? METHODS Between 2000 and 2021, 54 children with primary bone tumors underwent resection and reconstruction of the proximal femur at a single institution. During that time, allograft-prosthesis composite reconstruction was used in very young children, in whom we prioritize bone stock preservation for future surgeries, and children with good response to chemotherapy, while modular prosthesis reconstruction was used in older children and children with metastatic disease at presentation and poor response to chemotherapy. We excluded three children in whom limb salvage was not possible and 11 children who underwent either reconstruction with free vascularized fibular graft and massive bone allograft (n = 3), an expandable prosthesis (n = 3), a massive bone allograft reconstruction (n = 2), a rotationplasty (n = 1), standard (nonmodular) prosthesis (n = 1), or revision of preexisting reconstruction (n = 1). Further, we excluded two children who were not treated surgically, three children with no medical or imaging records, and three children with no follow-up. All the remaining 32 children with reconstruction of the proximal femur (12 children treated with modular prosthesis and 20 children treated with allograft-prosthesis composite reconstruction) were accounted for at a minimum follow-up time of 2 years. Children in the allograft-prosthesis group were younger at the time of diagnosis than those in the modular prosthesis group (median 8 years [range 1 to 16 years] versus 15 years [range 9 to 17 years]; p = 0.001]), and the follow-up in the allograft-prosthesis composite group was longer (median 5 years [range 1 to 23 years] versus 3 years [range 1 to 15 years]; p = 0.37). Reconstruction with hemiarthroplasty was performed in 19 of 20 children in the allograft-prosthesis composite group and in 9 of 12 children in the modular prosthesis group. A bipolar head was used in 16 of 19 children, and a femoral ceramic head without acetabular cup was used in 3 of 19 children in the allograft-prosthesis composite reconstruction group. All 9 children in the modular prosthesis group were reconstructed with a bipolar hemiarthroplasty. Reconstruction with total arthroplasty was performed in one child in the allograft-prosthesis composite group and in three children in the modular prosthesis group. For both groups, we calculated the cumulative incidence of reoperation for any reason and the cumulative incidence of reconstruction removal or revision arthroplasty; we also reported qualitative descriptions of serious complications treated nonoperatively in both groups. RESULTS The cumulative incidence of any reoperation at 10 years did not differ between the groups with the numbers available (36% [95% confidence interval 15% to 58%] in the allograft-prosthesis composite group versus 28% [95% CI 5% to 58%] in the modular proximal femoral replacement group). The cumulative incidence of reconstruction removal or revision arthroplasty at 10 years likewise did not differ between the groups with the numbers available (10% [95% CI 2% to 28%] versus 12% [95% CI 0% to 45%], respectively). In the allograft-prosthesis composite group (20 children), hip instability (n = 3), nonunion (n = 2), fracture of the greater trochanter (n = 1), screw loosening (n = 1), limb-length discrepancy (n = 1), and coxalgia due to acetabular wear (n = 1) were treated surgically without reconstruction removal. Complications treated without surgery included resorption of the allograft at the trochanteric region (n = 4), fracture of the greater trochanter (n = 4), limb-length discrepancy (n = 6), and coxalgia due to acetabular wear (n = 2). In the modular prosthesis group (12 children), hip instability (n = 1), coxalgia due to acetabular wear (n = 1), and limb-length discrepancy (n = 1) were treated surgically without reconstruction removal. Complications treated without surgery included hip instability (n = 2), stress shielding (n = 6), infection (n = 1), sciatic nerve palsy (n = 1), and limb-length discrepancy (n = 3). CONCLUSION Although the two groups of children were not directly comparable due to differences in age and clinical characteristics, both modular prosthesis and allograft-prosthesis composite reconstructions of the proximal femur after bone tumor resection appear to be reasonable options with similar revision-free survival and complications. Therefore, the type of reconstruction following proximal resection in children with bone sarcoma should be chosen taking into consideration factors such as patient age, bone size, implant availability, technical expertise, and the surgeon's preference. Although children treated with expandable prostheses were not included in this study, such prostheses may be useful in bridging the surgical defect while correcting residual limb-length discrepancies even though they face limitations such as small intramedullary diameter, short residual bone segments, as well as stress shielding, loosening, and breakage. LEVEL OF EVIDENCE Level III, therapeutic study.

中文翻译：

---

模块化假体和同种异体假体复合材料用于原发性骨肿瘤儿童近端股骨重建的并发症、重建生存率和功能结果是什么？


背景 儿童骨肿瘤切除后的股骨近端重建对骨科肿瘤科医生来说是一项要求很高的手术，因为骨尺寸较小，并且由于骨骺缺失而在骨骼生长结束时可能出现肢体长度差异。用于股骨近端的最常用重建类型是模块化假体和同种异体移植假体复合材料。据我们所知，之前没有研究比较原发性骨肿瘤儿童股骨近端模块化假体和同种异体移植假体复合重建后的结果。问题/目的 (1) 原发性骨肿瘤儿童股骨近端同种异体假体复合假体和模块化假体重建后因任何原因再次手术的累积发生率是多少？ (2) 这两个治疗组中重建切除或翻修关节置换术的累积发生率是多少？ (3) 不进一步手术或不进行重建切除的两个治疗组发生了哪些并发症？方法 2000 年至 2021 年间，54 名原发性骨肿瘤儿童在同一机构接受了股骨近端切除和重建手术。在此期间，同种异体假体复合重建用于非常年幼的儿童，我们优先考虑保留骨量以备将来手术，以及对化疗反应良好的儿童，而模块化假体重建则用于年龄较大的儿童和患有转移性疾病的儿童。表现和化疗反应不佳。 我们排除了 3 名无法保肢的儿童，以及 11 名接受游离血管腓骨移植和大块同种异体骨移植重建 (n = 3)、可扩张假体 (n = 3)、大块同种异体骨移植重建 (n = 2)、旋转成形术 (n = 1)、标准（非模块化）假体 (n = 1) 或现有重建的修正 (n = 1)。此外，我们排除了两名未接受手术治疗的儿童、三名没有医疗或影像记录的儿童以及三名没有随访的儿童。其余 32 名接受股骨近端重建的儿童（12 名接受模块化假体治疗的儿童和 20 名接受同种异体移植假体复合重建治疗的儿童）均在最短 2 年的随访时间内进行了统计。同种异体移植假体组的儿童在诊断时比模块化假体组的儿童更年轻（中位年龄 8 岁[范围 1 至 16 岁] vs 15 岁[范围 9 至 17 岁]；p = 0.001]），并且同种异体移植-假体复合组的随访时间更长（中位 5 年[范围 1 至 23 年] vs 3 年[范围 1 至 15 年]；p = 0.37）。同种异体移植假体复合组的 20 名儿童中有 19 名进行了半关节置换术，模块化假体组的 12 名儿童中有 9 名进行了半关节置换术重建。同种异体假体复合重建组19名儿童中有16名使用双极头，19名儿童中有3名使用不带髋臼杯的股骨陶瓷头。模块化假肢组的所有 9 名儿童均通过双极半关节置换术进行重建。同种异体移植假体复合组中的一名儿童和模块化假体组中的三名儿童进行了全关节置换术重建。 对于两组，我们计算了因任何原因再次手术的累积发生率以及重建切除或翻修关节置换术的累积发生率；我们还报告了两组非手术治疗严重并发症的定性描述。结果 10 年时再次手术的累积发生率在现有数据组之间没有差异（同种异体移植-假体复合组为 36% [95% 置信区间 15% 至 58%]，而异体移植假体复合组为 28% [95% CI 5%]至 58%]（模块化近端股骨置换组）。 10 年时重建切除或翻修关节成形术的累积发生率在具有可用数据的组之间同样没有差异（10% [95% CI 2% 至 28%] 与 12% [95% CI 0% 至 45%]，分别）。在同种异体假体复合组（20名儿童）中，髋关节不稳（n = 3）、骨不连（n = 2）、大转子骨折（n = 1）、螺钉松动（n = 1）、肢体长度不等(n = 1) 和髋臼磨损引起的髋部疼痛 (n = 1) 均通过手术治疗，无需重建切除。不进行手术治疗的并发症包括转子区域同种异体移植物吸收（n = 4）、大转子骨折（n = 4）、肢体长度不等（n = 6）和髋臼磨损引起的髋痛（n = 2） ）。在模块化假体组（12 名儿童）中，髋关节不稳定（n = 1）、髋臼磨损引起的髋部疼痛（n = 1）和肢体长度不等（n = 1）均通过手术治疗，无需重建切除。无需手术治疗的并发症包括髋关节不稳定 (n = 2)、应力屏蔽 (n = 6)、感染 (n = 1)、坐骨神经麻痹 (n = 1) 和肢体长度差异 (n = 3)。 结论 虽然两组儿童由于年龄和临床特征的差异而无法直接比较，但骨肿瘤切除后股骨近端模块化假体和同种异体移植假体复合重建似乎都是合理的选择，具有相似的免翻修生存期和并发症。因此，骨肉瘤儿童近端切除术后重建类型的选择应考虑患者年龄、骨大小、植入物可用性、技术专长和外科医生偏好等因素。尽管使用可扩张假体治疗的儿童未包括在本研究中，但此类假体可能有助于弥补手术缺陷，同时纠正残肢长度差异，即使他们面临髓内直径小、残余骨段短以及应力等限制。屏蔽、松动、破损。证据级别 III 级，治疗研究。