肌肉骨骼肿瘤治疗的进步使得恶性骨肿瘤患者的生存期更长，并且对于进行此类重建的患者来说，肿瘤内置假体的使用时间也更长。几项研究报告称，使用此类植入物可以增加血清金属离子。这些植入物的模块化引入了锥形连接腐蚀和沉降的风险，导致金属磨损颗粒释放，可能导致不良的局部组织反应或全身毒性。此外，这些植入物含有大表面积的钴和铬。目前尚不清楚血清离子水平升高的原因是锥体连接腐蚀还是植入物本身。据我们所知，之前没有研究报道过锥形连接处下沉。在这项研究中，我们试图（1）确定股骨模块化肿瘤内置假体中无放射照相锥形连接处下沉的存活率，以及（2）确定内置假体中的植入物特征1996年1月至2020年2月期间，资深作者在切除大腿和股骨的软组织或骨肿瘤后进行了150例近端或远端股骨置换术。其中，6%（150 名患者中的 9 名）在 2 年前失访，25%（150 名患者中的 37 名）由于随访期间缺乏 X 线平片而无法进行分析，13%（150 名患者中的 20 名）无法进行分析。 150）在随访 2 年前死亡，留下 56%（150 人中的 84 人）在这项回顾性研究中进行分析，患者索引切除和内置假体重建后的中位分析时间为 14 年（范围 2 至 31 年）股骨远端置换术患者的治疗期为 5 年（范围 2 至 19 年）。对涉及整个植入物的射线照片进行评估，以确定是否存在明显且清晰的锥形连接处下沉。使用回归分析检查了锥形连接数量、切除长度、塌陷连接数量以及从初次手术开始塌陷的时间之间的关联。总体而言，14%（84 名患者中的 12 名）接受了远端股骨置换术至少有一个模块化锥体的射线照相塌陷。 10 年无锥度沉降的存活率为 91%（95% CI 86% 至 96%），20 年存活率为 84%（95% CI 78% 至 90%）。所有患者均属于股骨远端置换组。下陷患者的中位随访时间为 15 年（范围 5 至 26 年）。 58%（12 人中的 7 人）的患者有两个连接点受累，25%（12 人中的 3 人）有 3 个连接点受累，17%（12 人中的 2 人）有 1 个连接点受累。除一名患者外，所有患者均在单个连接处出现下沉。中位沉降时间为 15 年（范围为 4.5 至 24.0 年）。所有出现这种情况的患者的下陷都是进行性的。 75% 的患者（12 人中的 9 人）锥体连接处完全下沉，25% 的患者（12 人中的 3 人）部分锥体连接处下沉。单变量和多变量回归分析并未表明我们研究的危险因素与沉降相关。两名出现连接处下沉的患者进行了翻修，一名患者因锥度骨折，另一名患者因远端连接处下沉而在总线交换过程中发生。远端股骨置换后，锥体损伤伴介入连接处晚期和渐进性下沉的情况并不少见。这种并发症的影响尚不清楚。进一步的研究应检查长期结果并将其与金属离子水平相关联。III 级，治疗研究。版权所有 © 2024，骨与关节外科医生协会。

Advancements in musculoskeletal oncologic treatment have allowed for longer survival of patients with malignant bone tumors and the associated longer use of tumor endoprostheses in those who have had such reconstructions. Several studies have reported on increased serum metal ions with the use of such implants. Modularity in these implants introduces the risk of taper junction corrosion and subsidence resulting in metal wear particle release that may cause an adverse local tissue reaction or systemic toxicity. Additionally, these implants contain a large surface area of cobalt and chromium. It is unclear whether the source of the increased serum ion levels was due to the taper junction corrosion or the implant itself. To our knowledge, no prior study has reported on taper junction subsidence.In this study we sought (1) to determine survivorship free from radiographic taper junction subsidence in a femoral modular tumor endoprosthesis, and (2) to identify the implant characteristics in the endoprostheses associated with taper subsidence.Between January 1996 and February 2020, the senior author performed 150 proximal or distal femur replacements following resections of soft tissue or bone tumors of the thigh and femur. Of those, 6% (9 of 150) of patients were lost to follow-up before 2 years, 25% (37 of 150) could not be analyzed due to absence of plain radiographs during follow-up, and 13% (20 of 150) died before 2 years follow-up, leaving 56% (84 of 150) for analysis in this retrospective study, with a median time for analysis of 14 years (range 2 to 31 years) after the index resection and endoprosthetic reconstruction for patients with distal femur replacements and 5 years (range 2 to 19 years) for patients with proximal femur replacement. Radiographs involving the entire implant were evaluated for the presence or absence of subsidence of the taper junction that was evident and clear to see if present. The association between the number of taper junctions, the length of resection, the number of collapsed junctions, and the time to collapse from the initial surgery were examined using regression analysis.Overall, 14% (12 of 84) patients with a distal femur replacement had radiographic collapse of at least one of the modular tapers. Survivorship free from taper subsidence was 91% (95% CI 86% to 96%) at 10 years and 84% (95% CI 78% to 90%) at 20 years. All patients were in the distal femur replacement group. The median follow-up of patients with subsidence was 15 years (range 5 to 26). Fifty-eight percent (7 of 12) of patients had two junctions involved, 25% (3 of 12) had three junctions, and 17% (2 of 12) had one junction involved. All but one patient had subsidence in a single junction. The median time to subsidence was 15 years (range 4.5 to 24.0 years). The subsidence was progressive in all patients who demonstrated it. The taper junction subsidence was complete in 75% (9 of 12) of patients and partial in 25% (3 of 12). Univariate and multivariable regression analyses did not show that the risk factors we studied were associated with subsidence. Two patients with junction subsidence were revised, one for taper fracture and one during busing exchange for distal junction subsidence.Taper damage with late and progressive subsidence of the intervening junction is not uncommon after distal femur replacement. The impact of such a complication is still unknown. Further studies should examine the long-term outcomes and correlate them with metal ion levels.Level III, therapeutic study.Copyright © 2024 by the Association of Bone and Joint Surgeons.