Analysis Of Risk Factors For Failure Of PFNA In Elderly Patients With Intertrochanteric Fracture

[objective] : To investigate the risk factors of failure of internal fixation in the treatment of intertrochanteric fractures by proximal antirotation intramedullary nail(PFNA)internal fixation and the effect of failure of internal fixation on hip joint function.[methods] : Retrospective analysis was performed on the clinical data of 184 patients with intertrochanteric fracture who were treated with PFNA internal fixation from January 2013 to June 2017 in our hospital and met the inclusion and exclusion criteria with complete follow-up data.According to the criteria of internal fixation failure,it is divided into the success group and the failure group,and then check the basic information of the patients,fractures AO type,spire(TAD),wall thickness,outer side parting,spiral blade area,osteoporosis index(Singh index),the positive side of the indicators such as difference of counterpoint.X-ray reexamination was conducted at 3,6,12,and 24 months after surgery to observe the imaging status of internal fixation.After the operation,the recovery status of the patients was known regularly,the time of postoperative weight-bearing activities and the hip joint function score(Harris score)of the patients were asked by telephone follow-up.The collected case data were statistically analyzed,and the Logistic regression model was established to analyze the risk factors that might lead to the failure of internal fixation.[results]: All the patients were follow up for 18~24 months with an average of(21.10 ± 2.15)months.During the follow up period,32 patients got failed internal fixation,accounted for 17.39%,while the remaining 152 patients had successful internal fixation,accounted for 82.61%.Compared the failed group with the non-failed group,there were no significant differences regarding to gender,age,deviation of lateral alignment and the blade position between the two(P>0.05).However,the failed group had significantly higher ratio of unstable fracture,less thickness of lateral cortex,greater deviation of anteroposterior alignment,severer osteoporosis in Singh index,greater tip apex distance and poorer integrity of lateral wall than the non-failed group(P<0.05).As results of multiple logistic regression analysis,unstable fracture(OR=8.299.P=0.044),thin thickness of lateral cortex(OR=1016.867.P=0.001),sever osteoporosis in Singh index(OR=6.453.P=0.023),great tip apex distance(OR=2.846,P=0.026)and poor integrity of lateral wall(OR=8.678 P=0.025)were the risk factors of PFNA failure.Three months after the operation,the Harris score of the failure group was(60.50±4.35),while that of the successful group was(80.30±6.37),which was significantly higher than that of the former group(t=7.66,P=0.002).At the last follow-up,Harris functional score of the successful group was(82.10±5.45),which was statistically significant(T=0.078,P=0.738).[conclusion] : The unstable fracture,thin thickness of lateral cortex,sever osteoporosis in Singh index,great tip apex distance and poor integrity of lateral wall are the risk factors of PFNA failure for femoral intertrochanteric fracture in the elderly,and once the internal fixation failure occurs,the hip joint functionwill be seriously reduced and the quality of life will be reduced.