Department of Musculoskeletal Oncology, HCG Hospital, Bangalore, India.
Department of Orthopaedic Oncology, Rizzoli Institute, Bologna, Italy.
Clin Orthop Relat Res. 2021 Aug 1;479(8):1780-1790. doi: 10.1097/CORR.0000000000001686.
Large, malignant bone tumors and revision limb salvage procedures often result in the resection of extensive lengths of the involved bone segment, leaving a residual segment of bone that may be too short to support a standard intramedullary stem for endoprosthetic reconstruction. Telescope allografting, in which an allograft is used to augment the remaining bone segment by telescoping it into the residual bone segment, was described for situations in which residual bone stock is insufficient after tumor resection or prosthetic revision. Apart from one study that first described the procedure [15], there are no other studies reporting the outcome of this telescopic concept for restoring bone stock.
QUESTIONS/PURPOSES: For patients younger than 18 years who underwent the telescopic allograft technique to augment a short segment of the proximal femur after resection of bone sarcomas who also underwent endoprosthesis reconstruction of the distal femur, we asked: (1) What is the survivorship free from removal of the telescopic allograft and the endoprosthetic stem at 7 years after surgery? (2) What proportion of these reconstructions will heal to the host bone without delayed union or nonunion? (3) What is the functional outcome based on the Musculoskeletal Tumor Society (MSTS) score?
We retrospectively studied our institutional database and identified 127 patients younger than 18 years who underwent surgery for a primary malignant bone tumor of the distal femur between December 2008 and October 2018. After excluding 16 patients undergoing amputation and rotationplasty and 57 patients undergoing recycled autograft/allograft reconstruction, 54 patients who underwent primary or revision distal femur endoprosthesis reconstruction were identified. Among these patients, we considered 15 patients who underwent telescopic allograft augmentation of the femur for analysis. One patient was lost to follow-up before 2 years but was not known to have died, leaving 14 for analysis at a median (range) 49 months (24 to 136 months) of follow-up. The indications for telescopic allograft augmentation of the femur in our institution were a proximal femur length of less than 120 mm after resection or resection of more than two-thirds of the total length of the femur. Ten of 14 patients underwent telescopic allograft augmentation as a revision procedure (distal femur resorption in five patients, endoprosthesis stem loosening in three patients, implant fracture in one patient, and infection in one patient), and the remaining four patients underwent telescopic allograft augmentation as a primary limb salvage procedure for large malignant bone tumors of the distal femur. The histologic diagnosis in all patients was osteosarcoma. At the time of telescopic allograft augmentation and reconstruction, the median age of the patients was 14 years (7 to 18 years). The size and the type of bone allograft to be used (femoral shaft or proximal femur) was planned before surgery, with consideration of the extent of resection, level of osteotomy, diameter of the host bone at the osteotomy site, and approximate diameter of the endoprosthesis stem to be used. The segment of the cylindrical allograft used for telescoping was thoroughly washed, prepared, and impacted onto the native femur to achieve telescoping and overlap. Serial digital radiographs were performed once a month for the first 6 months after the procedure, every 2 months until 1 year, and then every 6 months thereafter. Two surgeons in the department (at least one of which was involved in the surgery) retrieved and reviewed clinical notes and radiographs to determine the status of the telescopic allograft and endoprosthesis stem. We defined delayed union as radiological union at the osteotomy site more than 6 months after the procedure without additional surgery; we defined nonunion as no radiological evidence of callus formation at the osteotomy site 9 months after the procedure, necessitating additional surgery. The reviewers did not disagree about the definition of healing time. None of the patients missed radiographic follow-up. Kaplan-Meier survivorship free from removal of telescopic allograft and the endoprosthesis stem at 7 years after surgery was estimated. Patient function was assessed using the 1993 version of the MSTS [9], as determined by chart review of the institutional database performed by one of the surgeons from the department.
The survivorship free from removal of the telescopic allograft and endoprosthesis stem at 7 years after surgery was 80% (95% confidence interval 22% to 96%). The allograft united with the host bone in 100% (14 of 14) of the patients. Though 21% (3 of 14) had delayed union, no nonunions were seen. The median (range) MSTS score at the final follow-up interval was 27 (22 to 30).
Although this is a small group of patients, we believe that allograft segments help augment short bone stock of the proximal femur after long-segment resections, and the telescopic technique seems to be associated with a low proportion of nonunion or delayed union, which is one of the most common complications of allografts. Maintaining an adequate length of the proximal femur is important in preserving the hip, and this technique may be especially useful for young individuals who may undergo repeated revision procedures.
Level IV, therapeutic study.
大型恶性骨肿瘤和翻修保肢手术常导致受累骨段的广泛切除，留下一段可能太短而无法支撑标准髓内假体进行骨肿瘤重建的残余骨段。异体骨套叠术，即使用异体骨通过套叠到残余骨段中来增加剩余骨段的长度，用于描述肿瘤切除或假体翻修后残余骨量不足的情况。除了首次描述该手术的一项研究[15]外，没有其他研究报告这种用于恢复骨量的套叠概念的结果。
问题/目的：对于因骨肉瘤接受骨段切除且同时接受股骨远端假体重建的年龄小于 18 岁的患者，我们询问：(1)在手术后 7 年，从移除套叠异体骨和假体柄的角度来看，无生存率是多少？(2)这些重建中有多少比例能愈合到宿主骨，没有延迟愈合或不愈合？(3)基于肌肉骨骼肿瘤学会（MSTS）评分，功能结果如何？
我们回顾性地研究了我们的机构数据库，确定了 2008 年 12 月至 2018 年 10 月期间因原发性恶性骨肿瘤接受股骨远端手术的 127 名年龄小于 18 岁的患者。排除 16 名接受截肢和旋转成形术的患者和 57 名接受再循环自体/异体重建的患者后，确定了 54 名接受原发性或翻修股骨远端假体重建的患者。在这些患者中，我们考虑了 15 名接受套叠异体骨股骨段增强的患者进行分析。1 名患者在随访 2 年之前失访，但未死亡，因此有 14 名患者在中位数（范围）49 个月（24 至 136 个月）的随访中进行分析。在我们的机构中，采用异体骨套叠术增强股骨的指征为切除后股骨长度小于 120mm 或切除超过股骨总长度的三分之二。14 名患者中有 10 名（5 名患者为股骨远端吸收，3 名患者为假体柄松动，1 名患者为假体骨折，1 名患者为感染）接受了套叠异体骨增强作为翻修手术，其余 4 名患者接受了套叠异体骨增强作为大型恶性骨肿瘤的保肢手术。所有患者的组织学诊断均为骨肉瘤。在进行套叠异体骨增强和重建时，患者的中位年龄为 14 岁（7 至 18 岁）。在手术前计划使用的异体骨的大小和类型（股骨干或股骨近端），考虑到切除范围、截骨水平、截骨部位宿主骨的直径和拟使用的假体柄直径。用于套叠的圆柱形异体骨段在进行套叠和重叠之前进行了彻底清洗、准备和冲击。术后第一个 6 个月每月进行一次连续数字射线照相检查，直至 1 年每 2 个月一次，此后每 6 个月一次。部门的两名外科医生（至少有一名参与手术）检索并审查了临床记录和 X 光片，以确定套叠异体骨和假体柄的状态。我们将延迟愈合定义为术后 6 个月以上在截骨部位出现影像学愈合而无需额外手术；将无影像学证据的骨不连定义为术后 9 个月在截骨部位没有骨痂形成，需要额外手术。两位审稿人对愈合时间的定义没有分歧。没有患者错过影像学随访。估计手术后 7 年无套叠异体骨和假体柄移除的 Kaplan-Meier 生存率。通过对机构数据库的图表回顾，由部门的一名外科医生进行，评估患者的功能使用 1993 年版 MSTS[9]。
手术后 7 年无套叠异体骨和假体柄移除的生存率为 80%（95%置信区间为 22%至 96%）。所有患者（14 例中的 14 例）的异体骨均与宿主骨愈合。尽管 21%（3 例中的 3 例）发生延迟愈合，但未见骨不连。最终随访间隔的中位（范围）MSTS 评分为 27（22 至 30）。
尽管这是一个小患者群体，但我们认为异体骨段有助于在长段切除后增加股骨近端的短骨量，套叠技术似乎与低比例的骨不连或延迟愈合有关，这是异体骨最常见的并发症之一。保持股骨近端的适当长度对于维持髋关节的功能很重要，这种技术可能对可能需要反复翻修的年轻个体特别有用。
IV 级，治疗性研究。
