K. Staats, K. Vertesich, I. K. Sigmund, P. T. Funovics, R. Windhager, Department of Orthopedics and Trauma Surgery, Medical University of Vienna, Vienna, Austria.
B. Sosa, Hospital for Special Surgery, New York, NY, USA.
Clin Orthop Relat Res. 2020 May;478(5):1062-1073. doi: 10.1097/CORR.0000000000001106.
Distal femur replacement is frequently used for limb salvage after bone tumor resections. It is also used in patients with severe bone loss because of traumatic conditions or revision TKA. Some studies on distal femur replacement reported on revision-free survival without distinguishing between patients with oncologic diagnoses and those without, although these patients might be incomparable because of their differences in important patient- and disease-specific characteristics. This may lead to an inaccurate and undifferentiated interpretation of the results of survival analyses.
QUESTIONS/PURPOSES: (1) What is the overall cumulative incidence of revision surgery after cemented and cementless distal femoral replacement, as determined with a competing risk analysis? (2) Does the cumulative incidence of revision surgery change over time? (3) Are there differences in the cumulative incidence of revision surgery between patients with oncologic conditions and those without who are treated with cemented or cementless distal femoral replacement?
A total of 403 patients were possible candidates for distal femoral replacement. Of these, 56 patients elected to undergo different procedures, 83 were excluded because an expendable growing prosthesis was implanted, and 28 were lost to follow-up. Therefore, 229 patients who underwent distal femoral replacement for oncologic or non-oncologic reasons between 1983 and 2016 were retrospectively included in this study. The type of fixation method (cemented or cementless) was obtained from the patients' medical records, operation reports, and radiographic analyses from plain radiographs. All radiographs were standardized and obtained at standard time intervals in our institution. No algorithm regarding the fixation approach was followed. According to our data, patients receiving cementless fixation were younger and therefore likely to be more active than those receiving cemented fixation. The median follow-up duration of the overall cohort was 85 months (range 0.1-391 months). Patients who died or had revision surgery before the 2-year minimum follow-up interval were adequately considered using competing risk calculation. The reasons for revision surgery were classified using the classification system proposed by the International Society for Limb Salvage. A competing risk analysis was performed to estimate the cumulative incidence function of revision, accounting for death as a competing event. To evaluate the influence of potential prognostic factors, including diagnosis (oncologic versus non-oncologic), fixation (cemented versus cementless), year of distal femoral replacement, age, and sex on the occurrence of revision surgery, univariate and multivariable Fine and Gray models were applied.
The competing risks analysis revealed cumulative incidences of revision surgery for any cause (Types 1 to 5) of 26% (95% CI, 20.3%-31.9%) at 12 months, 37.9% (95% CI, 31.3%-44.4%) at 24 months, 52.6% (95% CI, 45.1%-59.5%) at 5 years, and 58.2% (95% CI, 50.1%-65.4%) at 10 years for all patients. Rotating hinge-type prostheses showed a lower cumulative incidence of revision surgery (41.6%; 95% CI, 31.8%-51%) than fixed-hinge prostheses did (64%; 95% CI, 50.5%-74.5% ) at 5 years (Gray's test: p = 0.01). According to the multivariate Fine and Gray model, the year of surgery did not have any effect on the risk of revision surgery (1994 to 2003: hazard ratio 0.70; 95% CI, 0.46-1.07); 2004 to 2016: HR 0.83; 95% CI, 0.52-1.34; p = 0.26). The multivariate analysis, adjusted for disease, sex, age, cementation, and year of surgery, revealed a difference in the risk of revision surgery between patients with oncologic disease and those with non-oncologic disease (HR 0.44 for oncologic versus non-oncologic; 95% CI, 0.22-0.87; p = 0.02) and a reduction in the risk of overall revision with cemented fixation in patients with oncologic disease (HR 0.53; 95% CI, 0.29-0.98; p = 0.03).
This study indicates that even with newer implants, there was a high incidence of revision surgery after distal femoral replacement. According to our analysis, patients with oncologic diagnoses have a lower likelihood of revision when the stem is cemented whereas the type of fixation did not impact patients with non-oncologic diagnoses. Because of differences in patient demographics (age, etiology of disease, and use of chemotherapy) and outcomes of fixation, oncologic and non-oncologic patients should be analyzed separately in survival studies about distal femoral replacement.
Level III, therapeutic study.
在肿瘤切除术后保肢时，常使用股骨远端置换；在因创伤或翻修 TKA 导致严重骨质流失时，也会使用股骨远端置换。一些关于股骨远端置换的研究报告了无翻修生存率，但并未区分肿瘤诊断患者和非肿瘤诊断患者，尽管这些患者因重要的患者和疾病特异性特征而无法比较。这可能导致对生存分析结果的不准确和不加区分的解释。
问题/目的：(1) 用竞争风险分析确定，骨水泥固定和非骨水泥固定的股骨远端置换后总的翻修手术累积发生率是多少？(2) 翻修手术的累积发生率随时间变化吗？(3) 患有肿瘤和非肿瘤疾病的患者，分别接受骨水泥固定和非骨水泥固定的股骨远端置换，他们的翻修手术累积发生率是否存在差异？
共有 403 名患者可能适合股骨远端置换。其中，56 名患者选择接受不同的手术，83 名因植入可延展生长型假体而被排除，28 名失访。因此，回顾性纳入了 1983 年至 2016 年间因肿瘤或非肿瘤原因接受股骨远端置换的 229 名患者。固定方法（骨水泥固定或非骨水泥固定）的类型取自患者的病历、手术报告和 X 线平片的影像学分析。我们机构的所有 X 线片均采用标准化和标准时间间隔拍摄。没有遵循任何关于固定方法的算法。根据我们的数据，接受非骨水泥固定的患者更年轻，因此可能比接受骨水泥固定的患者更活跃。总体队列的中位随访时间为 85 个月（范围 0.1-391 个月）。对于在 2 年最小随访间隔之前死亡或接受翻修手术的患者，我们使用竞争风险计算充分考虑了这些患者。翻修手术的原因使用国际保肢协会提出的分类系统进行分类。使用竞争风险分析来估计翻修的累积发生率函数，将死亡作为竞争事件进行考虑。为了评估潜在的预后因素（包括诊断[肿瘤与非肿瘤]、固定[骨水泥与非骨水泥]、股骨远端置换的年份、年龄和性别）对翻修手术发生的影响，我们应用了单变量和多变量 Fine-Gray 模型。
竞争风险分析显示，所有患者在 12 个月时任何原因（类型 1 至 5）的翻修手术累积发生率为 26%（95%CI，20.3%-31.9%），在 24 个月时为 37.9%（95%CI，31.3%-44.4%），在 5 年时为 52.6%（95%CI，45.1%-59.5%），在 10 年时为 58.2%（95%CI，50.1%-65.4%）。旋转铰链型假体的翻修手术累积发生率（41.6%；95%CI，31.8%-51%）低于固定铰链假体（64%；95%CI，50.5%-74.5%），差异具有统计学意义（Gray 检验：p = 0.01）。根据多变量 Fine-Gray 模型，手术年份对翻修手术的风险没有影响（1994 年至 2003 年：危险比 0.70；95%CI，0.46-1.07；2004 年至 2016 年：HR 0.83；95%CI，0.52-1.34；p = 0.26）。多变量分析调整了疾病、性别、年龄、骨水泥固定和手术年份，结果显示肿瘤性疾病患者和非肿瘤性疾病患者的翻修手术风险存在差异（肿瘤性疾病患者的 HR 为 0.44，非肿瘤性疾病患者为 0.22-0.87；p = 0.02），肿瘤性疾病患者骨水泥固定的总体翻修风险降低（HR 为 0.53；95%CI，0.29-0.98；p = 0.03）。
本研究表明，即使使用了更新的植入物，股骨远端置换后的翻修手术发生率仍然较高。根据我们的分析，对于带柄的假体，患有肿瘤的患者在使用骨水泥固定时发生翻修的可能性较低，而固定类型对患有非肿瘤的患者没有影响。由于患者人口统计学特征（年龄、疾病病因和化疗使用）和固定效果的差异，在关于股骨远端置换的生存研究中，应分别分析肿瘤和非肿瘤患者。
III 级，治疗性研究。
