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2022, Vol. 26 ›› Issue (6): 973-979Internal fixation failure after proximal femoral nail antirotation: causes and reoperation strategiesZhang Xinlong, Ci Wentao, Luo Kaiwen, Yan shi
Abstract: 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. Key words:intertrochanteric fractures, proximal femoral nail antirotation, internal fixation failure, helical blade cut out, collodiaphyseal angle, weight-bearing time, lateral femoral wall, unstable fractures |