Objectives: 

To compare retrograde intramedullary nail (RIMN) and open reduction internal fixation (ORIF) in very distal periprosthetic distal femur fractures (PDFFs) to determine whether RIMN is an acceptable option for these fractures that are often considered too distal for IMN due to limited bone stock.

Design: 

Retrospective comparative series.

Setting: 

Level 1 trauma center.

Patients: 

Patients were treated with fracture fixation for a very distal PDFF, defined as the fracture extending to the anterior flange of the implant or distal. Fifty-six patients met inclusion criteria, with 8 excluded for less than 12 months of follow-up.

Intervention: 

The intervention involved fracture fixation with RIMN or ORIF.

Main Outcome Measurements: 

The primary outcome was unplanned return to surgery. Secondary outcomes included fracture union, radiographic alignment, visual analog score, and Patient-Reported Outcome Measurement Information System (PROMIS) Physical Function (PF) and Pain Interference.

Results: 

The mean follow-up period was 27 months. Twelve patients were treated with ORIF and 36 with RIMN. Twenty-one fractures were at the flange, and 27 extended distal to the flange. There were no differences between fixation methods for reoperation, deep infection, nonunion, malunion, visual analog score pain score, and PROMIS Pain Interference score. The mean PROMIS PF score was higher in the RIMN group compared with that in the ORIF group. There were 5 reoperations in the RIMN group (14%) and 3 in the ORIF group (25%).

Conclusions: 

This is the largest series, to the best of our knowledge, of a subset of very distal PDFFs. The results suggest that RIMN may be an acceptable treatment option for these very difficult fractures.

Level of Evidence: 

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

中文翻译：

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股骨远端低位假体周围骨折的结果

目标： 

比较逆行髓内钉 (RIMN) 和切开复位内固定 (ORIF) 在极远端股骨远端假体周围骨折 (PDFFs) 中的疗效，以确定 RIMN 是否适合这些因骨量有限而通常被认为对 IMN 太远的骨折的选择.

设计： 

回顾性比较系列。

环境： 

一级创伤中心。

患者： 

患者接受了非常远端 PDFF 的骨折固定治疗，定义为骨折延伸到植入物的前缘或远端。56 名患者符合纳入标准，其中 8 名患者被排除在外，随访时间不到 12 个月。

干涉： 

干预涉及使用 RIMN 或 ORIF 进行骨折固定。

主要成果测量： 

主要结果是计划外返回手术。次要结果包括骨折愈合、射线照相对齐、视觉模拟评分和患者报告结果测量信息系统 (PROMIS) 身体功能 (PF) 和疼痛干扰。

结果： 

平均随访时间为 27 个月。12 名患者接受了 ORIF 治疗，36 名患者接受了 RIMN 治疗。21 处骨折位于法兰处，27 处延伸至法兰远端。再次手术、深部感染、骨不连、畸形愈合、视觉模拟评分疼痛评分和 PROMIS 疼痛干扰评分的固定方法之间没有差异。RIMN 组的平均 PROMIS PF 评分高于 ORIF 组。RIMN 组有 5 例再次手术（14%），ORIF 组有 3 例（25%）。

结论： 

据我们所知，这是最远端 PDFF 子集的最大系列。结果表明，对于这些非常困难的骨折，RIMN 可能是一种可接受的治疗选择。

证据等级： 

治疗级别 III。有关证据级别的完整描述，请参见作者说明。