BACKGROUND Limiting reoperation or revision after operative stabilization or endoprosthetic reconstruction of a pathologic subtrochanteric femur fracture reduces morbidity, but how best to achieve this remains controversial. Endoprosthetic reconstruction offers durable mechanical stability but may not be most appropriate in patients who are frail or who are not expected to survive more than a few months. For that reason, cumulative incidence survival (looking at the endpoint of reoperation or revision with death as a competing risk) and factors associated with revision after surgical stabilization or reconstruction-both of which remain poorly characterized to date-would help surgeons make better decisions on behalf of these patients. QUESTIONS/PURPOSES We analyzed patients who were operatively treated for pathologic subtrochanteric femur fracture, and we asked: (1) What is the cumulative incidence of reoperation and revision at 3 months, 1 year, and 2 years after surgery for pathologic subtrochanteric femur fracture in patients undergoing each treatment type with death as a competing risk? (2) What are the factors associated with implant revision after operative treatment of pathologic subtrochanteric femur fracture? (3) What is the overall survival of patients in this population after surgery? (4) How do clinical and surgical factors along with the frequency of complications compare in this population by operative treatment? METHODS Between January 2000 and December 2020, 422 patients underwent surgery for completed proximal femur pathologic fractures. After excluding patients with non-subtrochanteric femur fractures (71% [301]), fractures caused by primary tumors of bone (< 1% [2]), and insufficient data (1% [6]), we included 113 patients who underwent operative treatment of completed pathologic subtrochanteric femur fractures. Our study period spanned 20 years because although implant trends may have shifted, the overall operative objective for pathologic subtrochanteric femur fractures-restoring function and alleviating pain, regardless of the extent of bony union-have remained relatively unchanged during this period. Median follow-up time was 6 months (range 1 month to 20.6 years). Intramedullary nailing (IMN) was performed in 68% (77) of patients, proximal femur replacement (PFR) was performed in 19% (22), and open reduction and internal fixation (ORIF) was performed in 12% (14) of patients. IMN was performed in patients with a poor prognosis but in whom fracture stabilization was felt to be advantageous. In instances of complex fractures in which adequate reduction could not be achieved, ORIF was generally performed. PFR was generally performed in patients with a better prognosis in which long-term implant survival and patient function were prioritized. We found a higher proportion of women in the IMN group (73% versus 32% in PFR and 50% in ORIF; p = 0.001). Rapid growth tumors (Katagiri classification) were found in 25% of patients with IMN, 27% with PFR, and 43% with ORIF. The primary outcome was the cumulative incidence of reoperation or revision surgery after initial stabilization. Competing risk analysis with death as a competing event was performed to estimate the cumulative incidence for reoperation and revision. Factors associated with revision surgery were identified using the Cox proportional hazards model, which rendered HRs. All analyses were adjusted to control for potential confounders. RESULTS The cumulative incidence for reoperation at 2 years was 5% (95% confidence interval [CI] 4% to 6%) for IMN, 15% (95% CI 9% to 22%) for PFR, and 32% (95% CI 15% to 50%) for ORIF (p = 0.03). The cumulative incidence for revision at 2 years was 4% (95% CI 3% to 4%) for IMN, 4% (95% CI 2% to 6%) for PFR, and 33% (95% CI 15% to 51%) for ORIF (p = 0.01). Factors associated with revision surgery were radioresistant tumor histology (HR 8.5 [95% CI 1.2 to 58.9]; p = 0.03) and ORIF (HR 6.3 [95% CI 1.5 to 27.0]; p = 0.01). The 3-month, 1-year, and 2-year overall survival was 80% (95% CI 71% to 87%), 35% (95% CI 26% to 45%), and 28% (95% CI 19% to 36%), respectively. Thirty-day postoperative complications did not differ by fixation type, but 90-day readmission was highest after ORIF (3 of 14 versus 4 of 22 in PFR and 4% [3 of 77] in IMN; p = 0.03) Periprosthetic joint infection (PJI) was more common after salvage PFR (2 of 6) than primary PFR (1 of 22) (p = 0.04). CONCLUSION Primary PFR may be preferred for pathologic subtrochanteric femur fractures arising from radioresistant tumor types, as the cumulative incidence of revision was no different than for IMN while restoring function, alleviating pain, and offering local tumor control, and it less commonly develops PJI than salvage PFR. In complex fractures not amenable to IMN, surgeons should consider performing a PFR over ORIF because of the lower risk of revision and the added benefit of replacing the pathologic fracture altogether and offering immediate mechanical stability with a cemented endoprosthesis. Future studies might evaluate the extent of bone loss from local tumor burden, and this could be quantified and analyzed in future studies as a covariate as it may clarify when PFR is advantageous in this population. LEVEL OF EVIDENCE Level III, therapeutic study.

中文翻译：

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哪些因素与种植体翻修治疗病理性股骨转子下骨折有关？


背景 在病理性股骨转子下骨折的手术稳定或假体重建后限制再次手术或翻修可降低发病率，但如何最好地实现这一目标仍存在争议。内假体重建提供持久的机械稳定性，但可能不是最适合虚弱或预计存活时间不会超过几个月的患者。因此，累积发生率生存率 （将再次手术或翻修的终点与死亡视为竞争风险）和手术稳定或重建后翻修相关的因素 - 这两者迄今为止仍然没有得到充分表征 - 将有助于外科医生代表这些患者做出更好的决策。问题/目的我们分析了接受病理性股骨转子下骨折手术治疗的患者，并询问： （1） 在接受每种治疗类型且死亡为竞争风险的患者中，术后 3 个月、1 年和 2 年再次手术和翻修的累积发生率是多少？（2） 病理性股骨转子下骨折术后种植体翻修的相关因素有哪些？（3） 该人群患者术后总生存期是多少？（4） 通过手术治疗，该人群的临床和手术因素以及并发症发生率如何比较？方法 2000 年 1 月至 2020 年 12 月期间，422 例患者接受了完全性股骨近端病理性骨折手术。 在排除非股骨转子下骨折 （71% [301]）、原发性骨肿瘤引起的骨折 （< 1% [2]）和数据不足 （1% [6] 患者）后，我们纳入了 113 例接受完整病理性股骨转子下骨折手术治疗的患者。我们的研究期跨越了 20 年，因为尽管种植体趋势可能已经发生变化，但病理性股骨转子下骨折的总体手术目标——恢复功能和减轻疼痛，无论骨结合的程度如何——在此期间保持相对不变。中位随访时间为 6 个月 （范围从 1 个月到 20.6 年）。68% （77） 的患者进行了髓内钉固定 （IMN），19% （22） 的患者进行了股骨近端置换术 （PFR），12% （14） 的患者进行了切开复位和内固定 （ORIF）。对预后不良但认为骨折稳定有利的患者进行 IMN。在无法实现充分复位的复杂骨折的情况下，通常进行 ORIF。PFR 通常在预后较好的患者中进行，其中优先考虑长期植入物存活率和患者功能。我们发现 IMN 组中女性的比例更高 （PFR 为 73% vs 32%，ORIF 为 50%;p = 0.001）。在 25% 的 IMN 患者中发现快速生长肿瘤 （Katagiri 分类），27% 的 PFR 患者和 43% 的 ORIF 患者。主要结局是初始稳定后再次手术或翻修手术的累积发生率。以死亡为竞争事件进行竞争风险分析，以估计再次手术和翻修的累积发生率。 使用 Cox 比例风险模型确定与翻修手术相关的因素，该模型呈现 HRs。调整所有分析以控制潜在的混杂因素。结果 2 年再次手术的累积发生率为 IMN 为 5% （95% 置信区间 [CI] 4% 至 6%），PFR 为 15% （95% CI 9% 至 22%），ORIF 为 32% （95% CI 15% 至 50%） （p = 0.03）。2 年翻修的累积发生率为 IMN 为 4% （95% CI 3%， 4%），PFR 为 4% （95% CI 2%， 6%），ORIF 为 33% （95% CI 15%， 51%） （p = 0.01）。与翻修手术相关的因素是放射抵抗性肿瘤组织学 （HR 8.5 [95% CI 1.2， 58.9];p = 0.03） 和 ORIF （HR 6.3 [95% CI 1.5， 27.0];p = 0.01）。3 个月、 1 年和 2 年总生存率分别为 80% （95% CI 71%， 87%）、35% （95% CI 26%， 45%） 和 28% （95% CI 19%， 36%）。术后 30 天并发症因固定类型而异，但 ORIF 后 90 天再入院率最高 （PFR 14 例中有 3 例，22 例中有 4 例，IMN 为 4% [77 例中的 3 例];p = 0.03）挽救性 PFR 后假体周围关节感染 （PJI） （6 例中的 2 例） 比原发性 PFR （22 例中的 1 例） 更常见 （p = 0.04）。结论原发性 PFR 可能首选放射抗性肿瘤类型引起的病理性股骨转子下骨折，因为翻修的累积发生率与 IMN 无差异，同时恢复功能、减轻疼痛并提供局部肿瘤控制，并且与挽救性 PFR 相比，PJI 更不常见。对于不适合 IMN 的复杂骨折，外科医生应考虑进行 PFR 而不是 ORIF，因为 ORIF 的翻修风险较低，并且具有完全替代病理性骨折的额外好处，并且使用骨水泥内假体提供即时的机械稳定性。 未来的研究可能会评估局部肿瘤负荷引起的骨流失程度，这可以在未来的研究中作为协变量进行量化和分析，因为它可以阐明 PFR 何时在该人群中是有利的。证据级别 III 级，治疗研究。