Nomogram for predicting reoperation following internal fixation of nondisplaced femoral neck fractures in elderly patients

Abstract

Objective We aimed to evaluate risk factors and develop a nomogram for reoperation after internal fixation of nondisplaced femoral neck fractures (FNFs) in elderly patients. Methods We conducted a retrospective study involving a total of 255 elderly patients who underwent closed reduction and internal fixation with cannulated screw system for nondisplaced FNFs between January 2016 and January 2019. We collected data on demographics, preoperative radiological parameters, surgery, serum biochemical markers, and postoperative rehabilitation. In addition, we performed univariate and multivariate logistic regression analyses to determine independent risk factors for reoperation, and then developed a nomogram to assess the risks of reoperation. Besides, discriminative ability, calibration, and clinical usefulness of the nomogram were evaluated using the concordance index (C-index), the receiver operating characteristic (ROC) curve, calibration curve and decision curve analysis (DCA), respectively. We employed bootstrap method to validate the performance of the developed nomogram. Results Our analysis showed that among the 255 patients, 28 (11.0%) underwent reoperation due to osteonecrosis of the femoral head (14 cases), mechanical failure (8 cases) or nonunion (6 cases). All of the 28 patients underwent conversion surgery to arthroplasty. The multivariate logistic regression analysis demonstrated that preoperative posterior tilt angle ≥ 20°, Pauwel’s III type, younger patients, preoperative elevated levels of alkaline phosphatase (ALP), preoperative hypoalbuminemia, and early postoperative weight-bearing were independent risk factors for reoperation. In addition, the C-index and the bootstrap value of the developed nomogram was 0.850 (95% CI = 0.803–0.913) and 0.811, respectively. Besides, the calibration curve showed good consistency between the actual diagnosed reoperation and the predicted probability, while the DCA indicated that the nomogram was clinically valuable. Conclusions Our analysis showed we successfully developed and validated a nomogram for personalized prediction of reoperation after internal fixation of nondisplaced FNFs in elderly patients. This model would help in individualized evaluation of the need for reoperation and inform strategies aimed at eliminating the need for the reoperation.

Evaluation of the Posterior Tilt Angle in Predicting Failure of Nondisplaced Femoral Neck Fractures After Internal Fixation: A Systematic Review

“…Several studies have demonstrated high interobserver and intraobserver reliability of the PTA measurement method described by Palm et al, which relies on appreciating the cortical lines of the femoral head and neck. 8,10,18,21,25,26,28 If adequate lateral radiographs to measure the posterior tilt are difficult to obtain, augmenting the workup with a CT scan and assessing axial cuts has been shown to be an effective alternative. 21 This was defined as the "retroversion angle" by Shin et al, 21 which provides a similar assessment to PTA seen on lateral radiographs, demonstrating a 0.961 interobserver correlation coefficient.…”

“…Difficulty obtaining perfect lateral radiographs to measure the PTA because of soft-tissue envelope or other possibilities should be considered. Although a high intraobserver and interobserver reliability is reported in measuring the PTA on radiographs, 8,10,18,21,25,26,28 this is a potential source of bias. We believe it would be reasonable to obtain a CT should the concern of accurately measuring the PTA on a lateral radiograph arise.…”

“…Of the included studies, 3 were level 2 9,14,15 and the remaining 14 were level 3. 8,10,11,[16][17][18][19][20][21][22][23][24][25][26] The included studies were published between 2009 and 2020. Three studies were performed in South Korea 19,21,22 ; 2 each in the United Kingdom, 16,20 Denmark, 8,26 and Sweden 10,14 ; and 1 each in Italy, 17 Scotland, 15 Norway, 18 the Netherlands, 11 Finland, 24 China, 25 and Japan, 23 while 1 study spanned several countries.…”

Development and validation of a predictive nomogram for preoperative deep vein thrombosis (DVT) in isolated calcaneal fracture

“…Nomograms, which can leverage the predictive value of each risk factor and visualize the final prediction results, have been widely used in studies of clinical predictive models 29 – 32 . Thus, we successfully established and validated a nomogram to facilitate clinicians' preoperative DVT risk assessment in newly admitted patients with calcaneal fractures.…”

Patients With Femoral Neck Fractures Are at Risk for Conversion to Arthroplasty After Internal Fixation: A Machine‐learning Algorithm

“…The minimum required sample size for this predictive model with a binary outcome, 27 possible predictor parameters, an R 2 of 0.247 (based on the AUC of 0.858 in Zhu et al [54]), and an outcome prevalence of 18% is 830 patients [42][43][44].…”