Wedge effect following intramedullary hip screw fixation of intertrochanteric proximal femur fracture

Screening risk factors for the occurrence of wedge effects in intramedullary nail fixation for intertrochanteric fractures in older people via machine learning and constructing a prediction model: a retrospective study

PURPOSE

The wedge effect (V-effect) is a common complication in intramedullary nailing surgery for intertrochanteric fractures and can significantly affect postoperative outcomes. The purpose of this study was to screen risk factors for the intraoperative V-effect in intertrochanteric fractures and to develop a clinical prediction model.

METHODS

A total of 319 patients (77 patients who developed V-effects) from China were randomly divided into a training set (n = 223) and a validation set (n = 96) at a ratio of 7:3. The variables were screened via 3 machine learning methods, including least absolute shrinkage and selection operator (LASSO) regression, the Boruta algorithm, and recursive feature elimination (RFE). Variables that appeared in the three machine learning methods were included in multivariate logistic regression to construct predictive models. Spearman correlation analysis was used to exclude covariance between variables. Restricted cubic splines (RCSs) were used to analyze the relationships among femoral lateral wall thickness, BMI, and the V effect. The differentiation, calibration and clinical applicability of the model were assessed, and the reasonability of the model was analyzed.

RESULTS

Machine learning identified 8 variables that appeared in these 3 machine learning methods, and the covariance between these 8 variables was excluded (r < 0.6). BMI, surgical experience, a lesser trochanteric fracture, the thickness of the lateral wall, the insertion point, bone density, fracture classification, and holiday surgery were found to be risk factors for the occurrence of the V-effect via multivariate logistic regression. The RCS analysis revealed that the lateral wall thickness, BMI, and occurrence of the V effect were linearly related. The final predictive model had good differentiation, calibration and clinical applicability, and it had better predictive efficacy than the other models did.

CONCLUSION

This study employed three machine learning variable selection methods-the LASSO, RFE, and Boruta algorithms-to construct a V-effect predictive model. The model enables orthopedic surgeons to better understand the risk factors associated with the V-effect and provides a reference for surgeons to implement appropriate measures to reduce the incidence of the V-effect.

Risk factors of excessive sliding in elderly patients with intertrochanteric fractures treated with PFNA-II: a retrospective observational study

PURPOSE

Excessive sliding of cephalic components of cephalomedullary nails has been established to be significantly associated with the development of mechanical failures and unfavorable results in the surgical treatment of intertrochanteric fractures. This study aims to elucidate the risk factors that contribute to excessive sliding in elderly patients treated with PFNA-II devices for the fixation of intertrochanteric fracture.

METHODS

We conducted a retrospective analysis of patients aged 65 and older who presented with intertrochanteric fractures and underwent surgical treatment using PFNA-II devices at a university teaching hospital between January 2020 and December 2021. All patients were subjected to a minimum of one year of follow-up. We collected data on patient demographics, as well as preoperative, perioperative, and postoperative radiographic information, identifying mechanical failures during routine follow-ups. Patients were categorized into an excessive sliding group and a normal sliding group based on the sliding distance, with the optimal cut-off determined by receiver operating characteristic (ROC) curve analysis. Binary logistic regression was employed to identify independent risk factors associated with excessive sliding.

RESULT

Among the 507 eligible patients, the mean postoperative sliding distance was 4.45 mm (SD, 5.39 mm; range, 0-31.67 mm). The cut-off for excessive sliding was determined as 6.75 mm, with 61 patients (12.0%) classified as hving excessive sliding, of whom 18 (29.5%) experienced mechanical failures. Binary logistic analysis indicated that poor reduction quality (OR = 11.493, 95% CI: 3.386-39.014, P < 0.001), and Subtype P in LAT reduction (OR = 15.621, 95% CI: 5.984-40.779, P < 0.001) were independently associated with excessive sliding distance. Their associations were robust across subgroup analyses.

CONCLUSIONS

Poor reduction quality and the Subtype P in LAT reduction were identified as independent risk factors for excessive sliding. It is essential for surgeons to be mindful of these two risk factors during preoperative assessment and intraoperative procedures.

Impact of the nail insertion angle on the wedge effect in intramedullary nail fixation of intertrochanteric hip fractures

BACKGROUND

The wedge effect is known to be influenced by the insertion of the proximal femoral intramedullary nail through the fracture line and the large proximal diameter of the nail. However, the impact of the nail insertion angle (NIA) on the wedge effect remains unclear. This study aimed to investigate: (1) how to evaluate the NIA intraoperatively, (2) whether the NIA is associated with the wedge effect, (3) whether the NIA can serve as a reliable predictor of the wedge effect, (4) which factors affect the NIA, and (5) which surgical techniques can prevent the occurrence of the wedge effect associated with the NIA.

HYPOTHESIS

We hypothesized that an excessive NIA is related to the wedge effect and that lateral deviation of the entry point is associated with an excessive NIA.

PATIENTS AND METHODS

Intraoperative fluoroscopy images of patients who underwent intramedullary nail fixation for intertrochanteric hip fractures between 2013 and 2023 were analyzed. NIA and insertion point distance (IPD) were measured on hip anteroposterior radiographs with the guidewire inserted. Femoral shaft lateralization (FSL) and neck-shaft angle (NSA) were measured on hip anteroposterior radiographs before and after nail insertion; differences in FSL and NSA were calculated. A negative difference in FSL combined with a positive difference in NSA indicated the occurrence of the wedge effect. Pearson's correlation test was used to determine relationships between continuous variables (NIA, FSL, NSA, and IPD). Binary logistic regression analyzed the association between NIA and the wedge effect. Receiver operating characteristic (ROC) curve analysis was used to determine the threshold value of NIA, with predictive performance assessed using the area under the ROC curve (AUC). Other potential factors influencing the wedge effect were also examined.

RESULTS

A total of 408 patients were included. The mean NIA was 15.61 ± 4.49 °. Post-nail insertion, the average increase in FSL was 3.20 mm, and the average decrease in NSA was 1.90 °. Pearson's correlation test revealed that NIA was negatively correlated with the difference in FSL (R = 0.565, P < 0.001) and positively correlated with the difference in NSA (R = 0.509, P < 0.001). Binary logistic regression showed a significant correlation between NIA and the wedge effect (P < 0.001). ROC analysis indicated that the AUC for NIA was 0.813, with an optimal cutoff point of 14.85 °. IPD was positively correlated with NIA (R = 0.519, P < 0.001). Unstable fractures were associated with increased lateralization of the femoral shaft after nail insertion (P = 0.003).

DISCUSSION

The NIA is positively correlated with the wedge effect in intramedullary nail fixation of intertrochanteric hip fractures. The wedge effect tends to occur when the NIA is >14.85 °, particularly in unstable fractures. Lateral deviation of the entry point is associated with an excessive NIA. Adducting the affected limb, moving the entry point slightly medial and using a medial pusher may help control the NIA to less than 14.85 ° to reduce the wedge effect.

LEVEL OF EVIDENCE

III.

Unravelling variations: an examination of entry point selection in proximal femoral cephalomedullary nailing

BACKGROUND

The exact positioning of the cephalomedullary (CM) nail entry point for managing femoral fractures remains debatable, with significant implications for fracture reduction and postoperative complications. This study aimed to explore the variability in the selection of the entry point among trauma surgeons, hypothesizing potential differences and their association with surgeon experience.

METHODS

In this prospective multicenter study, 16 participants, ranging from residents to senior specialists, partook in a simulation wherein they determined the optimal entry point for the implantation of a proximal femoral nail antirotation (PFN-A; DePuy Synthes) in various femora. The inter- and intra-observer variability was calculated, along with comprehensive descriptive statistical analysis, to assess the variability in entry point selection and the impact of surgeon experience.

RESULTS

In this study, the mean distance from the selected entry points to the calculated mean entry point was 3.98 mm, with a smaller distance observed among surgeons with more than 500 implantations (ANOVA, p = 0.050). Intra-surgeon variability for identical femora averaged at 5.14 mm, showing no significant differences across various levels of surgical experience or training. Notably, 13.6% of selected entry points would not allow a proper intramedullary positioning of the implant, thereby rendering anatomical repositioning unfeasible. Among these impossible entry points, a significant skew towards anterior placement was observed (70.6% of the impossible entry points), with a smaller fraction being overly lateral (27.5%) or medial (13.7%). On a patient level, the impossibility rate varied widely from 0 to 35% among the different femora examined, with a significantly higher rate seen in younger patients (mean age 55.02 versus 60.32; t-test for independent samples, p = 0.04).

CONCLUSIONS

Significant variations exist in surgeons' selection of entry points for proximal femoral nailing, underscoring the task's complexity. Experience does not prevent the choice of unfeasible entry points, emphasizing the inadequacy of a universal approach and pointing towards the necessity for a patient-specific strategy for improved outcomes.

TRIAL REGISTRATION NUMBER

DRKS00032465.

Optimizing the Entry Point for Medullary Hip Screws

INTRODUCTION

Medullary hip screws (MHSs) are the most common treatment of intertrochanteric hip fractures because they can be used for varied fracture patterns and resist shortening. Identifying the appropriate MHS entry point can be intellectually and technically challenging. We aimed to quantify the variability in the ideal entry point (IEP) for MHSs.

METHODS

Standing alignment radiographs of 50 patients were evaluated using TraumaCad (Brainlab). The femoral neck shaft angle and the offset from the tip of the greater trochanter (GT) to the femur's longitudinal axis ('greater trochanter offset') were measured. Five MHS system templates were superimposed on the femur's longitudinal axis, and the distance from the GT tip to MHS's top center was measured. Five independent reviewers each templated 20 images such that all images were measured at least twice. A random sample of five images was selected for all five raters to measure and to calculate an intraclass coefficient Mean IEPs were compared with an independent sample Student t -test.

RESULTS

The mean GT offset was 13.5 ± 5.6 mm (range 12.9 to 26.7 mm). The mean neck shaft angle was 129.5 ± 4.0 (range 120 to 139). The mean IEP for nail systems ranged from 5.7 to 7.1 mm medial to the GT tip; there was no notable difference in pairwise comparison of nail systems or in aggregate. Intraclass coefficient for all ratings, measurements, and nail types ranged from moderate to good. Both intra-rater and inter-rater reliability were excellent.

DISCUSSION AND CONCLUSION

In a sample with broad variation in femoral anatomy, there is a specific, roughly 1.5 mm wide interval that is 6.4 mm medial to the GT tip that serves as the IEP for the most common MHS systems. No notable difference seems to exist in the IEP among these MHS systems.

How much of the superolateral femoral neck should be removed in intramedullary nail fixation for intertrochanteric fracture?

The objective of this study was to measure how much of the superolateral femoral neck should be removed to reduce the incidence of wedge effect. Simulating surgery: Computed Tomography images of 131 intertrochanteric fracture patients were included, three-dimensionally reconstructed, virtually reduced and implanted with Proximal Femoral Nail Antirotation blade-Ⅱ(PFNA-Ⅱ) nail. The antero-posterior length and media-lateral width of the intersection between superolateral femoral neck and PFNA-Ⅱ nail were measured. Retrospective study: The pre- and postoperative CT of 30 patients were collected. The average varus angle of the neck-shaft angle and the correlation between the angles and the difference in the actual and estimated width of the fragments removed were measured. Models of 108 patient were selected for analysis. The average antero-posterior length and media-lateral width were 14.46 mm (14.00-14.93 mm) and 9.33 mm (8.79-9.87 mm), respectively. The AO/OTA classification was not significantly associated with the outcome, but the gender was. In the retrospective study, the mean value of the varus angles was -4.58° (SE = 6.85°), and the difference of width was strongly positively correlated with the varus angle with a correlation coefficient of 0.698. Results obtained in this study can improve the understanding of this region and help surgeons to make appropriate preoperative planning to reduce the incidence of wedge effect. Retrospective study provided effective proof of the reliability of this study.

Inverse relationship between femoral lateralization and neck-shaft angle is a joint event after intramedullary nailing of per trochanteric fractures

This study explored the relationship between femoral lateralization and femoral neck-shaft angle after intramedullary nail (IM) fixation for per trochanteric fractures. 70 patients (AO/OTA 31A1-2) were investigated. Anteroposterior (AP) and lateral X-ray views pre- and post-operation were recorded. Patients were classified into three groups according to the position of the medial cortex of the head-neck fragment to that of the femoral shaft: being slightly superomedial (positive medial cortex support, PMCS), being smoothly contacted (neutral position, NP) or being displaced laterally (negative medial cortex support, NMCS). Patient demographics, femoral lateralization, and neck-shaft angle were measured and statistically analyzed pre- and post-operation. Functional recovery was evaluated by Harris score 3- and 6- months post-operation. All cases ultimately demonstrated radiographic fracture union. There was a tendency to have an increased neck-shaft angle (valgus alignment) in the PMCS group and increased femoral lateralization in the NP group (p < 0.05). Among those three groups, the change in femoral lateralization and neck-shaft angle was statistically different (p < 0.05). An inverse relationship between femoral lateralization and femoral neck-shaft angle was observed. Femoral lateralization increased correspondingly when the neck-shaft angle continuously decreased from the PMCS group to the NP group and then to the NMCS group, and patients in the PMCS group had better functional recovery than the other two groups (p < 0.05). Femoral lateralization was commonly produced after IM fixation for per trochanteric fractures. The fracture fixed in PMCS mode possesses the slightest change in femoral lateralization while maintaining valgus alignment of the femoral neck-shaft angle and good functional outcome, which is superior to NP or NMCS mode.

The application of a hollow trephine in femoral retrograde intramedullary nailing technique

PURPOSE

The purpose of this study was to describe and evaluate the use of a specially designed hollow trephine to create the entry point through the femoral condyle during retrograde interlocking intramedullary nailing for femoral fractures.

METHODS

From June 2019 to December 2021, we treated 11 patients (5 men, 6 women; mean age, 64 years; age range 40-77 years) with mid-distal femoral fractures by retrograde intramedullary femoral nailing using a self-designed hollow trephine for femoral condyle reaming and cancellous bone harvesting. The mode of all the nails is static. Patients were followed up at 1, 4, 8, and 12 weeks and for at least 6 months after surgery. The healing process and heterotopic ossification were evaluated by imaging. Partial weight bearing was permitted during the recovery period and complete weight bearing was permitted after clinical healing of the fracture displayed by X-ray.

RESULTS

The operation was successful in all patients. Over mean follow-up of 9.3 months (range, 6.0-12.0 months), all patients achieved clinical healing within three months. There were no complications such as knee joint infection, heterotopic ossification, knee joint adhesion and wedge effect.

CONCLUSION

The use of the hollow trephine during femoral retrograde intramedullary nailing helps avoid postoperative complications such as heterotopic ossification, knee joint adhesions, and wedge effect. It also facilitates bone graft harvesting.

Revision surgery in a middle-aged patient with pertrochanteric fracture nonunion due to wedge effect caused by cephalomedullary nail: A case report

Trochanteric femur fractures have traditionally been treated surgically with compression hip screws or cephalomedullary nails. With the increasing use of cephalomedullary nails, potential complications from this technique have surfaced. One of them is the potential for varus malreduction of trochanteric femur fractures, known as the "wedge effect", which is the distraction of fracture fragments generated during reamer and nail passage resulting in varus malalignment at the neck-shaft angle. Although trochanteric nonunion in the non-elderly is exceedingly rare, we experienced one such case after nailing due to the wedge effect that was subsequently successfully treated with a compression hip screw without bone grafting. Therefore, in the case of stable pertrochanteric fractures (AO/OTA 31A1) in younger patients, compression hip screw surgery may be the better choice of initial surgery to avoid later nonunion.

PFNA-II Internal Fixation Helps Hip Joint Recovery and Improves Quality of Life of Patients with Lateral-Wall Dangerous Type of Intertrochanteric Fracture

Objective

To analyze the effect of PFNA-II internal fixation on hip joint recovery and quality of life (QOL) in patients with lateral-wall dangerous type of intertrochanteric fracture.

Methods

One hundred and twelve patients with lateral-wall dangerous type of intertrochanteric fracture who underwent surgical treatment in our hospital from May 2017 to May 2019 were selected as the participants of the study. Based on the treatment method, all the enrolled patients were divided into two groups: proximal femoral nail antirotation (PFNA group; n = 59) who received closed reduction and minimally invasive PFNA internal fixation and dynamic hip screw group (DHS; n = 53) who received internal fixation. The clinical indicators, curative effect, hip function score, pain degree, postoperative QOL score, and complications were compared between the two groups.

Results

The operation time, intraoperative blood loss, postoperative drainage volume, and the incidence of postoperative complications in PFNA group were statistically lower than those in DHS group (P < 0.05). The curative effect in PFNA group was notably better than that in DHS group. There were no significant differences in scores of hip function, visual analogue scale (VAS), and QOL between the two groups before operation (P > 0.05). However, the hip function score and QOL score increased in both groups after surgery, and the increase was more significant in the PFNA group, while the VAS score decreased in both groups, and the decrease in PFNA group was more significant (P < 0.05).

Conclusion

PFNA internal fixation for the treatment of lateral-wall dangerous type of intertrochanteric fracture has the advantages of short operation time, less intraoperative blood loss, effective improvement of hip joint function, and fewer postoperative complications, which is worthy of clinical application.

Impact of Wedge Effect on Outcomes of Intertrochanteric Fractures Treated with Intramedullary Proximal Femoral Nail

The purpose of this study is to investigate the risk factors for wedge effect and its relevance between blade cut-out in patients with intertrochanteric fractures (ITF) treated with proximal femoral nail antirotation II (PFNA-II). A total of 113 patients with ITF treated with PFNA-II between 2012 and 2016 were retrospectively analyzed. Radiographic variables including preoperative fracture pattern, fracture classification, lateral wall fracture, and postoperative neck–shaft angle (NSA), femoral offset (FO), blade cut-out, and Parker’s ratio were measured for analysis. An average of 4.16° of varus malalignment in NSA and 5.5 mm of femoral shaft lateralization in FO was found post-operatively. The presence of lateral wall fracture was significantly related to post-operative varus change of NSA (p < 0.05). After at least one year of follow up, the blade cut-out rate was 2.65% (3/113), and Parker’s ratio was significantly higher in patients with blade cut-out (p = 0.0118). This study concluded that patients with ITF-present preoperative lateral wall fracture and postoperative higher Parker’s ratio in AP radiography showed higher incidence of wedge effect that might increase risk of blade cut out.

The influence of proximal femur canal size on reduction of intertrochanteric fracture with cephalomedullary nail

BACKGROUND

Malalignment is the most important risk factor for fixation failure after intertrochanteric fracture treated with a cephalomedullay nail (CMN). Malalignment continues to occur despite advances in surgical techniques.

HYPOTHESIS

We hypothesized that small femur canal size causes intra-operative reduction loss during cephalomedullary nail insertion.

METHODS

A retrospective study was performed from 2014 to 2017. Patients with acute intertrochanteric fracture implanted with the same sized CMN (Stryker, Mahwah, NJ, USA, diameter: 10mm, length: 170mm, degree 130) were included. Evaluated radiographic parameters included femoral canal size, corrected neck-shaft angle, and calcar reduction.

RESULTS

The study totally included and analyzed the data from 108 patients. Patients with smaller femoral canal size tended to have increased calcar distance according to Pearson's correlation coefficient analysis (r(106)=-0.805, p<0.001). Patients with calcar mal-reduction had higher corrected neck-shaft angle post-operatively. This observed correction tended to be lost during follow up.

CONCLUSIONS

Small femoral canal size resulted in poorer reduction quality. Reduction loss during nail insertion may be due to the whole proximal fragment instead of the superolateral femoral neck. Reaming the isthmus before nail insertion or choosing a smaller sized CMN is indicated in this patient population to prevent intra- or post-operative loss of reduction.

LEVEL OF EVIDENCE

III; retrospective study.

[Reasons of the guide pin eccentricity of helical blade during proximal femoral nail anti-rotation internal fixation for femoral intertrochanteric fractures]

Objective

To analyze the reasons and the influence of internal fixation about the guide pin eccentricity of helical blade during proximal femoral nail anti-rotation (PFNA) internal fixation for femoral intertrochanteric fractures.

Methods

A retrospective analysis of the intraoperative imaging data of 175 patients with femoral intertrochanteric fractures, who underwent closed reduction and PFNA internal fixation between January 2018 and January 2020, was performed. There were 76 males and 99 females with an average age of 79.8 years (mean, 61-103 years). The internal between admission and operation was 12-141 hours (median, 32 hours). According to AO/Orthopaedic Trauma Association (AO/OTA) classification, the fractures were rated as type 31-A1 in 64 cases and type 31-A2 in 111 cases. In the intraoperative fluoroscopy image by C-arm X-ray machine, the caputcollum-diaphysis (CCD) was measured after closed reduction and internal fixation, respectively; the angles between the center line of the head nail hole and the axis of proximal nail and between the axis of guide pin and proximal nail were measured, and the difference between the two angles was evaluated; the quality of fracture reduction was evaluated according to the alignment of the medial cortex, anterior cortex of the head and neck bone block, and femoral shaft cortex; the position of the helical blade in the femoral head was evaluated according to the Cleveland method.

Results

The CCDs of proximal femur were (134.6±6.8)° after closed reduction and (134.9±4.3)° after internal fixation. There was no significant difference between pre- and post-internal fixation ( t=0.432, P=0.766). The angles between the center line of the head nail hole and the axis of proximal nail and between the axis of guide pin and proximal nail were (125.4±2.44)° and (126.3±2.3)°, respectively, showing significant difference ( t=2.809, P=0.044). The difference between the two angles was (0.8±2.2)°. The guide pin eccentricity of helical blade occurred in 47 cases. After tapping the helical blade along the eccentric guide pin, 10 cases had fracture reduction loss, and 5 cases had a poor position of the helical blade in the femoral head.

Conclusion

During PFNA internal fixation, a variety of reasons can lead to the eccentric position of the guide pin of helical blade, including unstable fracture, soft tissue inserted, severe osteoporosis, mismatched tool, and fluoroscopic imaging factors. It is possible that the fracture end would be displaced again and the helical blade position may be poor when knocking into the helical blade along the eccentric guide pin. During operation, it should be judged whether the direction of the guide pin needs to be adjusted according to the eccentric angle.

Fluoroscopic landmarks to recognize iatrogenic varus displacement (wedge effect) during cephalomedullary nailing of intertrochanteric fractures

AIMS

Iatrogenic varus malreduction after intramedullary nailing of intertrochanteric fractures (wedge effect) may be more common than previously reported. The aim of study is to determine its incidence and to define easy fluoroscopic landmarks to recognize it intraoperatively.

PATIENTS AND METHODS

We included surgical procedures with residual varus malreduction and sufficient intraoperative fluoroscopy images to assess an intraoperative anatomical reduction at the beginning of the procedure. Two intraoperative fluoroscopic landmarks were defined to assess varus in the anteroposterior view: the position of the greater trochanter (GT) related to the femoral shaft (medialized GT sign), and the position (superior, centre or inferior) of the guide wire in both the neck and the head of the femur (cross wire sign). We describe our current method of treatment to avoid this complication.

RESULTS

A total of 369 extracapsular hip fractures were treated using PFNA and Gamma 3 systems. We found 55 (14.9%) fractures with a varus malreduction. Six were underreduced and fixed in varus. Thirty-five (9.48%) were well reduced by closed reduction but suffered a iatrogenic varus displacement when introducing the nail. 31 were female; mean age was 86.6 (range 70-97). Mean postoperative head-shaft angle was 119,2° range (113°-123°). Mean TAD was 24,37 range (14-36 mm).

CONCLUSION

Wedge effect (iatrogenic varus displacement of a well reduced intertrochanteric fracture when introducing the nail) could occur in at least 10% of intertrochanteric fractures. The medialized GT and the "crossing wire sign" seem to be good predictors of iatrogenic varus malalignement.

Reverse wedge effect following intramedullary nail fixation of trochanteric fracture, what does it imply?

Lag screw cut-out is the most common cause of fixation failure of trochanteric fractures. Intraoperative assessment of fracture reduction and fixation quality is vital to avoid fracture reduction and achieve good functional outcomes. In a recent study, Zhang et al. reported the occurrence of a reverse wedge effect after intraoperative nail insertion based on a new computed tomography(CT)-guided fracture classification system, which specifically happened to the basicervical facture type and resulted in valgus deformity with gapping at the medial inferior fracture line. Impingement between the reamer/nail and superolateral cortex of the femoral neck has been regarded as the main cause. Based on these findings, together with an extensive literature review, the practicality of the new fracture classification system, the definition of basicervical trochanteric fracture, and the mechanisms underlying the reverse wedge effect have been deeply discussed. More studies should be carried out in the future to analyse pre- and intraoperative related factors that could affect the intraoperative fragment migration effects and determine highly specific measures to address them.

Intertrochanteric Femur Fracture Treatment in Asia: What We Know and What the World Can Learn

Hip fractures are of great interest worldwide as the geriatric population continues to increase rapidly. Currently, surgeons prefer to use cephalomedullary nail for internal fixation of pertrochanteric/intertrochanteric fractures. This article summarizes 10 concepts in hip fracture treatment over the past 20 years, including fracture line mapping, proximal lateral wall and anterior cortex, posteromedial lesser trochanter-calcar fragment, anteromedial cortex support reduction, changes of fracture reduction after sliding and secondary stability, nail entry point and wedge-open deformity, tip-apex distance and calcar-referenced tip-apex distance, femoral anterior bowing and nail modification, long nails for wide medullary canal and large posterior coronal fragment, and postoperative stability score.

Reverse wedge effect following intramedullary nailing of a basicervical trochanteric fracture variant combined with a mechanically compromised greater trochanter

Background

To introduce an unreported intraoperative complication in intramedullary nailing (IN) of an anatomically reduced trochanteric fracture variant characterized by a basicervical fracture line and coronally disrupted greater trochanter (GT).

Methods

A total of 414 trochanteric fractures (TF) treated with intramedullary nails from 2013 to 2017 were included in this study. After analysis of intraoperative fluoroscopy data, 33 cases, including 21 females and 12 males, with a mean age of 72.5 years (33 to 96 years) were identified for internal rotation of the cephalocervical fragment and inferior opening at the basicervical fracture line caused by nailing a satisfactorily reduced TF. The morphological features of this group of patients were analyzed on computed tomography (CT) scan. On radiograph, the magnitude of the displacement and final femoral neck-shaft angle (NSA) were measured.

Results

CT analysis demonstrated that the basicervical fracture line and the posterolateral fragment (PLF) detached from the GT were the two dominant features of this cohort. They were classified according to the number of main fragments: a 3-fragmentary subgroup containing three consistent fragments (cephalocervical fragment, PLF and distal femoral shaft) and a 4-fragmentary subgroup embracing one additional fragment (lesser trochanter). The four subtypes were as follows: the 3-fragmentary S indicating a small PLF (6 cases), the 3-fragmentary M presenting a moderate PLF (3 cases), the 3-fragmentary L standing for the PLF involving whole lesser trochanter (LT) (4 cases) and the 4-fragmentary GL incorporating separated PLF and LT fragments (20 cases). Geological analysis demonstrated that the majority of the basicervical fracture lines (81.8%) just crossed the center of the piriformis fossa, while the others marginally involved the medial wall of the GT. Postoperatively, the mean width of the inferior opening at the basicervical region was 9.2 ± 4.6 mm. The mean NSA was 135.2 ± 7.8 degrees. The comparison between the 3- and 4-fragmentary subgroups revealed no significant differences in magnitude of displacement and NSA.

Conclusion

This unreported intraoperative complication predominantly occurred in the intramedullary nailed basicervical trochanteric fracture variant combined with a PLF from the GT. The magnitude of the secondary displacement was substantial and resulted in a relative valgus reduction. This secondary displacement was caused by an impingement of the reamer with the superolateral cortex of the cephalocervical fragment and should be addressed during the operation.

Level of evidence

Therapy IV.

A Percutaneous Threaded Wire as a Clamp Technique for Avoiding Wedge Deformity While Nailing Intertrochanteric Femur Fractures

Hip fractures are common injuries managed by the orthopaedic surgeon, and within the umbrella of hip fractures, intertrochanteric femur fractures constitute a significant portion of these injuries. Recent trends have shown an increased usage of cephalomedullary nails for these injuries. A known potential complication of this technique is the generation of a wedge deformity creating a varus alignment, especially when the cranial portion of the intertrochanteric fracture exits at or near the starting point of the nail. Although the biomechanics of this phenomenon are well described, few reports have shown techniques to help avoid this phenomenon. Here, we present a novel technique we have found useful to help prevent the wedge deformity incorporating commonly available instruments.

Cementless total hip arthroplasty following failed internal fixation for femoral neck and intertrochanteric fractures: A comparative study with 3-13 years' follow-up of 96 consecutive patients

BACKGROUND

The aim of this study was to investigate the postoperative outcomes of cementless Total hip arthroplasty (THA) following failed internal fixation for femoral neck and intertrochanteric fractures.

METHOD

Ninety-six cementless THAs for failed internal fixation after femoral neck fracture (59, group I) and intertrochanteric fracture (37, group II) with a minimum follow-up of 3 years were analyzed. Clinical and radiologic evaluations were performed on all patients.

RESULTS

The intraoperative blood loss and operating time were significantly increased in group II (p = 0.001, p = 0.001, respectively). Harris hip score at last follow-up was significantly improved in group I (p = 0.007) but, there were no differences in hospital stay, Koval score at last follow-up, and perioperative complications between both groups. Long femoral stems for diaphyseal fitting were frequently used in group II (32/37, 86%) (p = 0.001). Radiographically, none of the acetabular cups showed evidence of migration, loosening. All cases showed stable fixation of the femoral stem at last follow-up.

CONCLUSIONS

Outcomes of cementless THA following failed internal fixation for femoral neck and intertrochanteric fractures were satisfactory; increased intraoperative blood loss, operating time, and requirement of long femoral stem should be considered in the latter type of fracture.

Optimizing stability in AO/OTA 31-A2 intertrochanteric fracture fixation in older patients with osteoporosis

Objectives

To compare the functional and radiographic outcomes of InterTAN nail (IT) and proximal femoral nail anti-rotation (PFNA) for managing primary AO/OTA 31-A2 intertrochanteric hip fractures (IHFs) in older osteoporotic patients.

Methods

Patients aged 60 years or older who received surgical treatment for IHFs (AO/OTA 3.1A2.1-A2.3) with IT or PFNA were retrospectively evaluated. The primary outcome was the postoperative treatment failure rate. The secondary outcome was the Harris Hip Score (HHS).

Results

A total of 326 osteoporotic cases (326 hips: IT, n = 162; PFNA, n = 164) were assessed with a mean follow-up of 43.5 months (range, 38–48 months). For the entire cohort, the incidence of postoperative treatment failure (periprosthetic fracture and reoperation) was 29/326 (8.9%); the IT-treated cohort (7/162, 4.3%) had a significantly lower rate compared with the PFNA-treated cohort (22/165, 13.3%). The incidence of postoperative periprosthetic fractures was significantly lower in the IT-treated cohort than in the PFNA-treated cohort (2.5% vs 7.9%). The postoperative HHS at the final follow-up was not significantly different between the groups.

Conclusion

IT might show a better outcome in managing osteoporotic AO/OTA 31-A2 IHFs in terms of periprosthetic fracture and reoperation compared with PFNA.

Preventing Wedge Deformities When Treating Intertrochanteric Femur Fractures With Intramedullary Devices: A Technical Tip

Intertrochanteric femur fractures are common injuries associated with significant patient morbidity and mortality and high societal costs. Although intramedullary devices have shown promises for treating a wide range of intertrochanteric femur fractures, improper technique can lead to malalignment, fracture displacement, and/or iatrogenic fractures. In particular, a "wedge effect" has been described, in which the passage of conical reamers and the intramedullary nail itself results in the distraction of intertrochanteric fragments with lateralization of the shaft from the femoral neck and varus malalignment. Here, we describe the mechanism by which this deformity is generated and describe techniques for preventing it, including the use of a modified starting point and an alternative to the conical opening reamers.

Biomechanics-Hot Topics Part II

Orthopaedic surgery and biomechanics are intimately partnered topics in medicine. Biomechanical principles are used to design implants and fashion treatment protocols. Although it would seem that biomechanical principles in the design of fixation devices and fracture repair constructs have been already finalized, there are several points of controversy remaining. New technology has raised new questions, while at the same time, we still do not fully understand simple clinical principles such as time of fracture healing depending on the construct used. This review looks at several of these current controversies to better understand what work is needed in fracture care going forward.

Tip-Apex Distance Is Most Important of Six Predictors of Screw Cutout After Internal Fixation of Intertrochanteric Fractures in Women

Background

Six risk factors for screw cutout after internal fixation of intertrochanteric fractures have been reported. The purpose of the present study was to evaluate and compare the impact of the 6 risk factors of screw cutout to clarify the most important one.

Methods

We enrolled 8 consecutive patients who had screw cutout and 48 random control subjects after internal fixation of intertrochanteric fractures treated with proximal femoral nail antirotation systems at our institution. All of the patients were female. The group that had screw cutout and the control group were retrospectively evaluated and compared with respect to the OTA/AO classification, presence of a posterolateral fragment, types of reduction pattern on anteroposterior and lateral radiographic images, position of the screw, and the presence of a tip-apex distance (TAD) of ≥20 mm. The impact of each factor on screw cutout was assessed using backward stepwise multivariable logistic regression analysis with the Akaike information criterion. Risk stratification was assessed using classification and regression tree (CART) analysis.

Results

Among 6 risk factors, only a TAD of ≥20 mm had a significant impact on screw cutout, with an adjusted odds ratio of 12.4 (95% confidence interval, 1.6 to 129.0; p = 0.019). CART analysis also demonstrated that a TAD of ≥20 mm was the most important risk stratification factor (p < 0.001).

Conclusions

Among the 6 previously reported screw cutout-related factors, only a TAD of ≥20 mm was associated with screw cutout after internal fixation of intertrochanteric fractures with proximal femoral nail antirotation systems.

Level of Evidence

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Intertrochanteric fracture: Association between the coronal position of the lag screw and stress distribution

BACKGROUND/PURPOSE

The best position of the lag screw in the femoral head for the fixation of intertrochanteric fracture is controversial. Traditional view suggests that it should be positioned in the central axis of the femoral neck with a tip-apex distance (TAD) of <25 mm, but the mechanical properties have not been reported yet. Herein, we aimed to investigate internal fixation with the lag screw placed in different positions on the femoral coronal plane by performing a finite element analysis and to identify a reasonable lag screw position after the internal stress distributions at the femoral head.

METHODS

A three-dimensional finite element model of a healthy male's femur was set up, on which the intertrochanteric fracture model with proximal femoral nail antirotation (PFN-A) was based. Nine modalities of the model were established in accordance with different lag screw positions in the femoral head. Three-dimensional finite element calculations were conducted, and the distribution trends of characteristic high-stress concentration points were observed.

RESULTS

The area of high-stress concentration was distributed from the top of the femoral head to the medial cortex of the trochanteric region. Four characteristic high-stress concentration points were observed, and the following trends indicated that the lower the position of the lag screw, the greater its length.

CONCLUSIONS

A longer and lower lag screw may make the fixation sustain greater stress, reduce bone tissue stress correspondingly in intertrochanteric fractures fixated with PFN-A, and sustain greater stress and more cyclic load at the same bone density.

Removal of a broken trigen intertan intertrochanteric antegrade nail

Implant breakage is a serious complication after cephalomedullary nailing for unstable intertrochanteric fracture. Failure usually occurs at the lag screw hole in the nail body. On the other hand, lag screw failure is extremely rare and occurs around the nail-lag screw junction. We experienced rare mechanical failure of the Intertan nail, which showed breakage at the lag screw hole and failure of the integrated compression screw underneath the main lag screw.

Conversion to total hip arthroplasty after failed proximal femoral nail antirotations or dynamic hip screw fixations for stable intertrochanteric femur fractures: a retrospective study with a minimum follow-up of 3 years

Background

Conversion to total hip arthroplasty (CTHA) is a relatively common procedure after a failed dynamic hip screw (DHS) or proximal femoral nail anti-rotation (PFNA) fixation of intertrochanteric fractures, but there have been far fewer reports specifically describing the long-term results of CTHA after failed treatments of stable intertrochanteric fractures with DHS or PFNA. The aim of the present study was to compare the clinical and radiological outcomes of CTHA after failed PFNA or DHS fixations of stable intertrochanteric fractures after a minimum follow-up of 3 years.

Methods

Between January 2005 and April 2014, we retrospectively reviewed 142 active elderly patients treated at our institution (a single institution study). A total of 72 patients (72 hips; 41 women, 31 men; mean age 76.9 years old; range 60–92 years old) who underwent conversion of a failed PFNA to a THA were compared with 70 patients (70 hips; 36 women, 34 men; mean age 75.0 years old; range 60–90 years old) who underwent CTHA after a failed DHS fixation. The mean follow-up periods were 48 (range 43–52) and 48 (range 44–52) months for the DHS and PFNA groups, respectively. Clinical and radiologic evaluations were performed on all patients. The primary outcome was the Harris Hip Score (HHS). The secondary outcomes were the complication rates.

Results

The Harris Hip Score (HHS) improved from 50.61 ± 3.23 preoperatively to 85.28 ± 4.45 at the last follow-up in the PFNA group and from 51.46 ± 3.90 to 84.50 ± 4.34 in the DHS group, with no significant differences noted between the groups at each follow-up (P > 0.05). However, the complication rate in the converted DHS patients was significantly higher (42.9%) than that in the converted PFNA patients (20.8%; P = 0.003). Thirty-seven PFFs (2.4%) occurred during a mean follow-up of 44.4 months. The incidence of periprosthetic fractures was found to be significantly higher (P = 0.021) for the DHS group (15.7%) than for the PFNA group (4.2%).

Conclusions

CTHA after failed DHS fixations of stable intertrochanteric fractures might be associated with a significantly higher complication rate than CTHA after failed PFNA fixations. Therefore, PFNA patients with stable intertrochanteric fractures may be more suitable for CTHA.

Predictive variables of open reduction in intertrochanteric fracture nailing: a report of 210 cases

BACKGROUND

Factors that impede closed reduction in intertrochanteric fractures remain unknown. This study was designed with the aim of establishing radiological variables that can predict an open reduction when nailing those type of fractures.

MATERIALS AND METHODS

Observational prospective study carried out between March 2013 and March 2015. Patients of both gender who suffered an intertrochanteric fracture, and who were surgically treated by intramedullary nailing (PFN-A), were included. Patients were evaluated by means of a questionnaire designed in 12 de Octubre Trauma department. Radiological parameters assessed preoperatively, after fracture reduction in the traction table, and after fixation were: calcar, lateral wall and posterior buttress integrity or disruption; lesser trochanter location, varus or valgus deformities, and flexion or extension of the proximal fragment.

RESULTS

Association between open reduction and the following types of fractures was statistically significant (p<0.001): subtypes A2.3, A3.2 and A3.3 of AO classification and subtypes IV and V of Evans classification. There were four radiological parameters associated with the need for open reduction: disruption of lateral wall (p<0.0000), posterior wall fracture (p<0.001), calcar (p<0.004) and malalignment in the axial view (p<0.001).

CONCLUSIONS

Open reduction seems to be necessary for complex fracture patterns such as A2.3, A3.2 and A3.3 types of AO/OTA classification, as well as types IV and V of Evans classification. There are four major radiological parameters that can predict the need of approaching the fracture site: posterior buttress, calcar disruption, lateral wall disruption and proximal fragment flexion. The development of high quality evidence regarding this topic is necessary due to the vast impact that open reduction can have on elderly patients.