Background 

Endoprosthetic reconstruction after oncologic resection of bone tumors requires stable fixation between the prosthesis and residual host bone. Compressive osseointegration has been developed as an alternative to traditional stemmed implants to address the challenges and complications of achieving this fixation. Sufficient time has now passed from the advent of compressive implants to allow for an assessment of the intermediate-term and long-term results of this form of fixation.

Questions/purposes 

At a minimum follow-up of 10 years after implantation of a compressive osseointegration device for oncologic reconstruction: (1) What is the risk of periprosthetic fracture, aseptic loosening, or implant breakage resulting in revision surgery for endoprosthesis removal? (2) What is the long-term cortical response at the host-endoprosthesis interface as visualized on plain radiographs?

Methods 

A single-center, retrospective study was performed between 2002 and 2010, in which 110 patients with primary bone sarcoma of the proximal or distal femur were considered for oncologic resection and reconstruction. Patients were considered for a compressive osseointegration endoprosthesis if they were 50 years of age or younger, had not previously received femoral radiation, had no metabolic disease impairing bone healing, were not diagnosed with metastatic disease, and had life expectancy greater than six months. Of the 110 patients, 25 were treated with a compressive osseointegration implant of the proximal or distal femur, and 85 patients were treated with conventional stemmed implants or amputation because of older age, advanced disease, metabolic comorbidities, inability to tolerate a nonweightbearing postoperative period, or in the case of rotationplasty, patient preference. All patients who received this device during the period of study were considered eligible for inclusion in this review. The median (range) age was 18 years (7 to 50), and 13 of 25 patients were men. Five patients died of disease before the minimum follow-up duration of 10 years; two underwent amputation due to local recurrence and three died with the implant in situ, leaving 20 patients for complete analysis. Median follow-up was 144 months, and all 20 surviving patients had a minimum follow-up of 10 years (121 to 230 months). The primary endpoint was reoperation and implant removal for periprosthetic fracture, aseptic loosening, or mechanical breakage of any component of the compressive device in the endoprosthesis. In final analysis, death was considered a competing event to revision surgery, and cumulative incidence was reported after competing-event analysis. A secondary aim was radiographic evaluation of the host-implant interface to assess the long-term cortical response to compressive osseointegration.

Results 

Spindle fracture or loosening was noted in three patients, and the remaining 17 patients maintained the compression device until the final follow-up. The risk of reoperation for aseptic loosening, periprosthetic fracture, or mechanical breakage of the implant using a competing risks estimator was 12% at 10 years (95% CI 0% to 26%). These complications occurred within 29 months of the index surgery; no patients had implant loosening or mechanical breakdown after this initial period. On radiographic assessment, 14 patients demonstrated cortical hypertrophy of the bone-implant interface, six patients had maintenance of the native cortical contour, and no patients had cortical atrophy or narrowing at the implant interface.

Conclusion Long-term follow-up in patients with compressive osseointegrative endoprosthetic devices demonstrated no late revisions because of periprosthetic fracture, aseptic loosening, or implant breakage in this cohort with a minimum 10-year follow-up. There was no evidence of late-onset cortical atrophy or stress shielding at the host-implant interface. This study supports the long-term stability of the interface between host bone and the endoprosthesis in compressive osseointegration devices.

Level of Evidence 

Level IV, therapeutic study.

中文翻译：

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至少 10 年随访期的股骨加压假体骨整合的长期手术结果是什么？

背景 

骨肿瘤肿瘤切除后的内假体重建需要假体和残留宿主骨之间的稳定固定。压缩骨整合已被开发为传统带柄种植体的替代方案，以解决实现这种固定的挑战和并发症。自压缩植入物出现以来已经过去了足够的时间来评估这种固定形式的中期和长期结果。

问题/目的 

植入用于肿瘤重建的压缩性骨整合装置后至少随访 10 年：(1) 假体周围骨折、无菌性松动或种植体破损导致内假体移除翻修手术的风险有多大？(2) 平片上显示的宿主-内置假体界面处的长期皮质反应是什么？

方法 

2002 年至 2010 年间进行了一项单中心回顾性研究，其中 110 名股骨近端或远端原发性骨肉瘤患者考虑进行肿瘤切除和重建。如果患者年龄不超过 50 岁、之前未接受过股骨放疗、没有影响骨愈合的代谢性疾病、未诊断出患有转移性疾病，并且预期寿命超过 6 个月，则可以考虑使用压缩性骨整合内置假体。在 110 名患者中，25 名接受了股骨近端或远端压缩性骨整合植入物治疗，85 名患者因年龄较大、晚期疾病、代谢合并症、无法忍受术后非负重期而接受了传统带柄植入物或截肢治疗，或者在旋转成形术的情况下，患者偏好。在研究期间接受该设备的所有患者均被视为有资格纳入本次审查。中位（范围）年龄为 18 岁（7 至 50 岁），25 名患者中有 13 名是男性。5 名患者在最短 10 年随访时间之前死于疾病；两名患者因局部复发而接受截肢，三名患者在植入原位后死亡，剩下 20 名患者需要进行完整分析。中位随访时间为 144 个月，所有 20 名幸存患者的最短随访时间为 10 年（121 至 230 个月）。主要终点是因假体周围骨折、无菌性松动或内置假体中压缩装置任何部件的机械断裂而进行的再次手术和植入物移除。在最终分析中，死亡被认为是修复手术的竞争事件，并且在竞争事件分析后报告累积发生率。次要目标是对宿主-种植体界面进行放射学评估，以评估皮质对压缩骨整合的长期反应。

结果 

3 名患者出现纺锤体断裂或松动，其余 17 名患者维持加压装置直至最后随访。使用竞争风险估计器，10 年时因无菌性松动、假体周围骨折或种植体机械断裂而再次手术的风险为 12%（95% CI 0% 至 26%）。这些并发症发生在初次手术后 29 个月内；在此初始阶段之后，没有患者出现种植体松动或机械损坏。在放射学评估中，14 名患者表现出骨-种植体界面的皮质肥大，6 名患者维持了天然皮质轮廓，没有患者在种植体界面出现皮质萎缩或狭窄。

结论对使用压缩性骨整合内置假体装置的患者进行的长期随访表明，在该队列中，至少随访 10 年，没有因假体周围骨折、无菌性松动或种植体破损而进行晚期翻修。没有证据表明宿主-植入物界面出现迟发性皮质萎缩或应力屏蔽。这项研究支持压缩骨整合装置中宿主骨和内置假体之间界面的长期稳定性。

证据水平 

IV级，治疗研究。