股骨近端防旋髓内钉修复后内固定失效:原因和再手术的策略分析

Internal fixation failure after proximal femoral nail antirotation:causes and reoperation strategies

背景:股骨近端防旋髓内钉在治疗股骨转子间骨折方面优势显著,但仍有3.35%-31.08%的内固定失效率发生,且类型多样,原因复杂,因此,对股骨近端防旋髓内钉各类内固定失效的原因进行总结分析,同时明确长钉与短钉选择的分界以及术后内固定失效后的再手术策略,是临床更好针对性预防相应的内固定失效以及后续治疗的关键。目的:探讨应用股骨近端防旋髓内钉治疗股骨转子间骨折术后发生各类内固定失效的原因和再手术策略。方法:检索PubMed、中国知网和万方数据库中2010年1月至2021年5月发表的相关文献。英文检索词为"intertrochanteric fractures,risk factors,failure of internal fixation,PFNA,nonunion of fracture,cut out,cut in,helical blade position,osteoporosis,Long and short intramedullary,Revision surgery",中文检索词为"股骨转子间骨折、PFNA、内固定失败、螺旋刀片切出、内固定物周围骨折、骨折不愈合、骨质疏松、长短髓内钉、再手术策略",将股骨近端防旋髓内钉治疗股骨转子间骨折术后发生各种类型的内固定失效原因及再手术策略进行归纳总结。结果与结论:螺旋刀片的切出、髋内翻、骨折不愈合、头钉的退钉、内固定物断裂及内植物周围骨折是股骨近端防旋髓内钉术后内固定失败常见的6种类型。(1)刀片位置放置不当、颈干角及前倾角的复位不佳、不稳定的骨折类型、严重的骨质疏松以及高龄是刀片切出的主要原因。(2)髋内翻可由股骨距后内侧的骨缺损致术后股骨内侧缺乏支撑引起,也常继发于其他内固定失效类型,延长负重时间可以有效避免此种情况发生。(3)骨折不愈合受全身及局部因素影响,对于远端锁钉的使用需慎重考虑。(4)骨质疏松是导致刀片退出最常见原因,严重骨质疏松患者术中有必要对螺旋刀片用长尾帽固定,术后延长负重时间。(5)骨折复位不佳、骨不连、不稳定骨折使用远端锁钉及主钉与髓腔不匹配都有可能造成内固定物断裂。(6)植入物周围骨折常与骨髓腔和髓内钉不匹配、主钉入钉点位置偏差致皮质撞击率增加以及局部应力集中相关,临床上应选择合适长度的主钉,避免"中裤效应"发生。(7)对于长短钉的选择,除某些特殊病例外,建议临床医师选择短钉固定,关于A3型转子间骨折长、短髓内钉的选择,是临床医师需要继续探索的一个方向。(8)关于股骨近端防旋髓内钉内固定失效后的再手术策略,从股骨头的破坏程度、骨折部位情况以及骨缺损3个方面来确定二次翻修策略是一种合适的选择。

BACKGROUND:The proximal femoral nail antirotation has significant advantages in the treatment of intertrochanteric fractures,but there is still a 3.35%-31.08%failure rate of internal fixation.Internal fixation failures are not only of various types,but also of complex causes.Therefore,to summarize and analyze the causes of the failure of various proximal femoral nail antirotation internal fixations,and to clarify the boundary between the selection of long nails and short nails as well as the secondary surgical strategies after the failure of postoperative internal fixation is the key to better targeted prevention of the corresponding internal fixation failure and subsequent treatment in clinical practice.OBJECTIVE:To investigate the causes of various types of internal fixation failure secondary surgical strategies after the application of proximal femoral nail antirotation for the treatment of intertrochanteric fractures.METHODs:To search the relevant documents from January 2010 to May 2021 on PubMed,CNKI and Wanfang databases,with English search terms as"intertrochanteric fractures,risk factors,failure of internal fixation,PFNA,nonunion of fracture,cut out,cut in,helical blade position,osteoporosis,long and short intramedullary,revision surgery".Chinese search terms were"intertrochanteric fracture,PFNA,failure of internal fixation,helical blade cut-out,periprosthetic fracture,non-union of fracture,osteoporosis,long and short intramedullary,revision surgery".In addition,the reasons for the failure of various types of internal fixation and secondary surgical strategies after proximal femoral nail antirotation treatment of intertrochanteric fracture of femur were summarized.REsULTs AND CONCLUsION:The six common types of internal fixation failure after proximal femoral nail antirotation surgery are helical blade cut out,hip varus,fracture nonunion,head nail withdrawal,internal fixation fracture,and fracture around the implant.(1)Improper placement of the blade,poor reduction of the neck shaft angle and anteversion angle,unstable fracture type,severe osteoporosis and high age are the main reasons for blade cut out.(2)Hip varus can be caused by postoperative lack of support of the medial femur due to a bone defect in the posterior medial part of the proximal femur,or secondary to other types of fixation failure,which can be avoided by delaying the loading time.(3)Fracture nonunion is affected by systemic and local factors,and the use of distal locking nails should be carefully considered.(4)Osteoporosis is the most common cause of blade withdrawal.In patients with severe osteoporosis,it is necessary to use a long-tailed cap to fix the spiral helical during the operation and delayed the postoperative loading time.(5)Failure of internal fixation may result from poor reduction,bone nonunion,and unstable fractures with distal locking nails and a mismatch between implant and bone.(6)Fractures around the implant are often associated with the mismatch between the bone marrow cavity and the intramedullary nail,the deviation of the main nail entry point,resulting in increased cortical impingement rate and local stress concentration.Clinically,the appropriate length of the main nail should be selected to avoid the occurrence of the"middle trousers effect".(7)Except for some special cases,it is recommended that clinicians choose short nails for fixation.In addition,the choice of long and short intramedullary nails for A3 type intertrochanteric fractures is a direction that orthopedic surgeons need to continue to explore in the future.(8)For the reoperation strategy after the failure of proximal femoral nail antirotation internal fixation,it is a good choice to determine the second revision strategy from three aspects:the degree of femoral head destruction,the fracture site and the bone defect.