Construction of a prediction model for intraoperative wedge effect during PFNA fixation in intertrochanteric femoral fractures
YAN Kang
LI Wenbo
YUE Xijun
ZHU Ziqiang
Abstract：Objective To develop and validate a prediction model for the intraoperative wedge effect during proxi-mal femoral nail antirotation(PFNA)fixation in patients with intertrochanteric femoral fractures.Methods A total of 597 patients with intertrochanteric femoral fractures were retrospectively enrolled.The occurrence of wedge effect was de-termined based on postoperative radiographic criteria(a reduction in the neck-shaft angle by≥4° compared to the contra-lateral side and lateral displacement of the femoral shaft by≥7 mm).Admission-related clinical data were collected.Least absolute shrinkage and selection operator(LASSO)regression was used to screen predictive variables,and multi-variable Logistic regression analysis was performed to identify independent influencing factors and to construct a nomo-gram prediction model.Internal validation was conducted using the bootstrap resampling method(1,000 repetitions).The concordance index(C-index),area under the receiver operating characteristic curve(AUC),and Brier score were calculated,and calibration curves and decision curve analysis were plotted to evaluate the discrimination,calibration,and clinical applicability of the model.Results Intraoperative wedge effect occurred in 83 patients(13.9%)and did not occur in 514 patients(86.1%).Involvement of the greater trochanter(OR=18.022,95%CI:8.546-38.005),lat-eral wall fracture(OR=9.431,95%CI:4.703-18.910),body mass index(BMI)>24 kg/m²(OR=8.670,95%CI:4.228-17.778),and bone mineral density(BMD)T-score≤-2.5(OR=9.236,95%CI:4.548-18.755)were identi-fied as risk factors for the wedge effect(all P<0.05).In contrast,absence of lesser trochanter displacement(OR=0.386,95%CI:0.205-0.730)was a protective factor(P<0.05).The nomogram model constructed based on these fac-tors yielded an area under the receiver operating characteristic curve(AUC)of 0.922(95%CI:0.895-0.950),with a corrected C-index of 0.918 and a Brier score of 0.070.The calibration curve showed close agreement with the ideal ref-erence line,and decision curve analysis demonstrated that the model provided a net clinical benefit within a threshold probability range of 0.05-0.50.Conclusions Greater trochanter involvement,lateral wall fracture,BMI>24 kg/m²,and BMD T-score≤-2.5 are risk factors for the intraoperative wedge effect,while absence of lesser trochanter displace-ment is a protective factor.The prediction model incorporating these factors exhibits favorable discrimination,calibration,and clinical utility.
Keywords：intertrochanteric femoral fractureproximal femoral nail antirotation fixationwedge effectprediction model
Publication Date：2026-02-25
Online Publishing Date：2026-03-19(First online date of this platform, not the publication date of the document)
Pages：5( 109-113 )