New tip-apex distance and calcar-referenced tip-apex distance cut-offs may be the best predictors for cut-out risk after intramedullary fixation of proximal femur fractures

[Rotationally stable screw anchor (RoSA) vs. Gamma3 Nail (G3N) in pertrochanteric femoral fractures : A functional outcome analysis]

BACKGROUND

The pertrochanteric femoral fracture (PFF) represents one of the most common fracture types throughout Germany. To enable early mobilization of patients, the primary surgical goal is load-stable osteosynthesis. Implant failure still represents the largest group of implant-related complications (>80%).

OBJECTIVE

The aim of the study was to document and analyze the influence of the implant on the functional outcome and an evaluation of the rotationally stable screw anchor (RoSA) vs. Gamma3 nail.

MATERIAL AND METHODS

In a retrospective study 43 patients with PFF (AO 31A1-A3) were included in the study. The influence of the implant on the functional outcome was assessed by 2 standardized questionnaires (SF-36, NMS (New Mobility Score)) and analyzed in a retrospective evaluation.

RESULTS

In the study no significant differences in functional outcome scores ≥ 1 year after osteosynthesis of the PFF could be shown depending on the implant used. There is an overall tendency for a better outcome in the G3N group.

DISCUSSION/CONCLUSION

In the literature the superiority of intramedullary nailing over extramedullary implants is continually discussed. Implant failure is still the most frequent complication. In intramedullary implants, such as the G3N, the primary cause is failure of the head-neck component. For conventional extramedullary implants the biomechanical properties on the femoral shaft also pose a challenge in the case of unstable PFF. The further development of the RoSA to an intramedullary implant could combine the advantages of intramedullary load carriers with the advantages of the blade-screw combination in the head-neck fragment and lead to a reduction in implant-associated complications.

Predictive value of tip-apex distance and calcar-referenced tip-apex distance for cut-out in 398 femoral intertrochanteric fractures treated in a private practice with dynamic intramedullary nailing

Introduction

Cut-out, a biomechanical complication, is one of the most common causes of internal fixation failure of trochanteric hip fractures. The tip-apex distance (TAD) and the calcar-referenced tip-apex distance (CalTAD) have been suggested as the radiographic parameters that most predict the risk of cut-out. The purpose of this study was to check whether these two factors could predict implant cut-out in a series 398 of intertrochanteric hip fractures, treated by dynamic intramedullary nailing with the Trigen Intertan short nail.

Methods

We reviewed 398 consecutive intertrochanteric fractures included in a prospective study and treated in a single private hospital by the same surgeon. The radiographic parameters were obtained from anteroposterior (AP) and axial hip plain radiographs before surgery, immediately postoperatively, and every 3 weeks after surgery until 3 months postoperatively, and every month until the 6-month follow-up. The concept of medial cortex support (MCS) was also analyzed as a criterion for evaluating the quality of fracture reduction.

Results

The overall cut-out rate was 2.3% (9/398). The significant parameters in the univariate analysis were AO fracture type, quality of fracture reduction (p = 0.02), TAD (p < 0.001), CalTAD (p = 0.001), and quality of reduction. No statistically significant relationships were observed between the occurrence of cut-out and sex, age, fracture side, and American Society of Anesthesiologists type. Varus collapse and cut-out were only found in cases of negative MCS (22.2% and 77.8%, respectively). Multivariate analysis showed that only TAD showed an independent significant relationship to cut-out (p < 0.001). In this study, CalTAD has no predictive value in the multivariable analysis.

Conclusions

Our findings differed from those in previous reported studies suggesting that CalTAD is the best predictor of cut-out. According to our data, careful optimal reduction ensuring stable fixation with TAD >25 mm reduced the occurrence of cut-out after dynamic intramedullary nailing of intertrochanteric fractures.

Tip-apex distance as a risk factor for cut-out in cephalic double-screw nailing of intertrochanteric femur fractures

Aims

Proximal femur fractures treatment can involve anterograde nailing with a single or double cephalic screw. An undesirable failure for this fixation is screw cut-out. In a single-screw nail, a tip-apex distance (TAD) greater than 25 mm has been associated with an increased risk of cut-out. The aim of the study was to examine the role of TAD as a risk factor in a cephalic double-screw nail.

Methods

A retrospective study was conducted on 112 patients treated for intertrochanteric femur fracture with a double proximal screw nail (Endovis BA2; EBA2) from January to September 2021. The analyzed variables were age, sex, BMI, comorbidities, fracture type, side, time of surgery, quality of reduction, pre-existing therapy with bisphosphonate for osteoporosis, screw placement in two different views, and TAD. The last follow-up was at 12 months. Logistic regression was used to study the potential factors of screw cut-out, and receiver operating characteristic curve to identify the threshold value.

Results

A total of 98 of the 112 patients met the inclusion criteria. Overall, 65 patients were female (66.3%), the mean age was 83.23 years (SD 7.07), and the mean follow-up was 378 days (SD 36). Cut-out was observed in five patients (5.10%). The variables identified by univariate analysis with p < 0.05 were included in the multivariate logistic regression model were screw placement and TAD. The TAD was significant with an odds ratio (OR) 5.03 (p = 0.012) as the screw placement with an OR 4.35 (p = 0.043) in the anteroposterior view, and OR 10.61 (p = 0.037) in the lateral view. The TAD threshold value identified was 29.50 mm.

Conclusion

Our study confirmed the risk factors for cut-out in the double-screw nail are comparable to those in the single screw. We found a TAD value of 29.50 mm to be associated with a risk of cut-out in double-screw nails, when good fracture reduction is granted. This value is higher than the one reported with single-screw nails. Therefore, we suggest the role of TAD should be reconsidered in well-reduced fractures treated with double-screw intramedullary nail.

Application of deep learning algorithms in classification and localization of implant cutout for the postoperative hip

OBJECTIVE

This study aims to explore the feasibility of employing convolutional neural networks for detecting and localizing implant cutouts on anteroposterior pelvic radiographs.

MATERIALS AND METHODS

The research involves the development of two Deep Learning models. Initially, a model was created for image-level classification of implant cutouts using 40191 pelvic radiographs obtained from a single institution. The radiographs were partitioned into training, validation, and hold-out test datasets in a 6/2/2 ratio. Performance metrics including the area under the receiver operator characteristics curve (AUROC), sensitivity, and specificity were calculated using the test dataset. Additionally, a second object detection model was trained to localize implant cutouts within the same dataset. Bounding box visualizations were generated on images predicted as cutout-positive by the classification model in the test dataset, serving as an adjunct for assessing algorithm validity.

RESULTS

The classification model had an accuracy of 99.7%, sensitivity of 84.6%, specificity of 99.8%, AUROC of 0.998 (95% CI: 0.996, 0.999) and AUPRC of 0.774 (95% CI: 0.646, 0.880). From the pelvic radiographs predicted as cutout-positive, the object detection model could achieve 95.5% localization accuracy on true positive images, but falsely generated 14 results from the 15 false-positive predictions.

CONCLUSION

The classification model showed fair accuracy for detection of implant cutouts, while the object detection model effectively localized cutout. This serves as proof of concept of using a deep learning-based approach for classification and localization of implant cutouts from pelvic radiographs.

A Good Tip-Apex Distance Does Not Make Up For a Poor Reduction in Intertrochanteric Hip Fractures Treated with an Cephalomedullary Nail: The Utility of the Neck-Shaft Angle in Preventing Fixation Failure

PURPOSE

Determine if any fracture characteristics or radiographic parameters were predictive of fixation failure [FF] within 1 year following cephalomedullary nailing for intertrochanteric fractures.

METHODS

A consecutive series of intertrochanteric hip fracture patients (AO/OTA 31A) treated with a cephalomedullary nail were reviewed. Pre-fixation (neck-shaft angle [NSA], distance from ischial tuberosities to greater and lesser trochanters, integrity of lesser trochanter, and fracture angulation) and post-fixation (post-fixation NSA, posteromedial cortex continuity, lag screw position, tip to apex distance [TAD], and post-fixation angulation and translation) radiographic parameters were measured by blinded independent reviewers. The FF and non-FF groups were statistically compared. Logistic regression was performed to determine radiographic parameter correlates of FF.

RESULTS

Of 1249 patients, 23 (1.8%) developed FF within 1 year. The FF patients were younger than their non-FF counterparts (77.2 years vs 81.0 years, p=0.048), however there were no other demographic differences. The FF cohort did not differ in frequency of TAD over 25 mm (4.3% vs 9.6%, p=0.624) and had decreased mean TAD (13.6mm vs 16.3mm, p=0.021) relative to the non-FF cohort. The FF cohort had a higher rate of a post-fixation coronal plane NSA more than 10° different from the contralateral side (delta NSA>10°, 34.8% vs 13.7%, p=0.011) with the majority fixed in relative varus. For every 1° increase in varus compared to the contralateral side the odds of FF increased 7% (OR=1.065, 95%CI[1.005-1.130], p=0.034) on univariate analysis. On univariate logistic regression, patients with an absolute post-fixation NSA of 10° or more of varus compared to contralateral were significantly more likely to have a FF (OR=3.139, 95%CI[1.067-8.332], p=0.026).

CONCLUSION

Despite an acceptable TAD, post-fixation NSA in relative varus as compared to the contralateral side was significantly associated with failure in intertrochanteric hip fractures fixed with a cephalomedullary nail.

LEVEL OF EVIDENCE

Prognostic Level III.

[Research progress on evaluation methods for head-neck nail position in femoral intertrochanteric fractures]

Objective

To summarize the research progress on the evaluation methods of head-neck nail positions in femoral intertrochanteric fractures.

Methods

The literature about the evaluation methods of head-neck nail positions for femoral intertrochanteric fractures in recent years was extensively reviewed, and research progress in the aspects of evaluation methods, clinical applications, and limitations were summarized.

Results

The position of head-neck nails in femoral intertrochanteric fractures is closely related to postoperative complications of head-neck nail cutting. Currently, the tip-apex distance (TAD) and femoral head zoning are widely used to evaluate the position of head-neck nails. The main opinion in the literature is that the use of TAD and femoral head zoning can effectively reduce the incidence of head-neck nails cutting. Parker's ratio, as one of the evaluation methods, has been controversial in subsequent studies and has not been widely used in clinical practice. The TAD as referenced to the calcar (CalTAD), which was modified based on TAD, has been gradually accepted by the clinic, but whether it is better than the TAD has not yet been conclusively determined. In recent years, new evaluation methods have been proposed to supplement the previous evaluation methods, such as the tip-neck distance ratio (TNDR) and the standardized TAD (STAD) to avoid the limitations of the TAD and the CalTAD by the volume of the femoral head, and the axis-blade angle (ABA) to supplement the direction of the head-neck nails channel, but at present the clinical application is relatively underutilized, and the validity of the method needs to be further verified.

Conclusion

Currently, there are many methods for evaluating the position of head-neck nails in femoral intertrochanteric fractures, TAD<25 mm combined with head-neck nails placed in the middle-middle quadrant or lower-middle quadrant of the femoral head division is currently a highly recognized assessment in the literature, but the optimal assessment is still controversial, and further research needs to be studied.

A new scoring system for predicting cut-out risk in patients with intertrochanteric femur fractures treated with proximal femoral nail anti-rotation

OBJECTIVE

The objectives of this study were to: (1) determine all the potential risk factors defined in the literature for cut-out after proximal femoral nail anti-rotation in managing intertrochanteric fractures and (2) make a reliable prediction about the likelihood of cut-out by developing a quantitative scoring system.

METHODS

Four hundred eighty patients who were operated on for an intertrochanteric femur fracture were included in the study. The patients were evaluated retrospectively. Radiological parameters known to affect cut-out, including tip apex distance (TAD), calcarreferenced TAD (CalTAD), and reduction quality, were also used to evaluate the patients. Additionally, the classification of the fracture according to the cortical thickness index for osteoporosis, the Charlson comorbidity index for additional comorbidities, and the Arbeitsgemeinschaft Für Osteosynthesefragen classification were evaluated.

RESULTS

The cut-out rate among all patients was 7.2%. Cut-out risk could be predicted by gender, TAD, CalTAD, and reduction quality. Female gender, TAD > 29.45, CalTAD > 31.75, and acceptable or poor reduction quality significantly increased the cut-out risk. Based on the chi-square analysis, it was determined that there was a significant relationship between the cut-out risk and the variables of TAD, CalTAD, reduction quality, gender, and fracture type (P=.000, P=.000, P=.000, P=.008, P=.016, respectively). Logistic regression analysis showed a strong correlation between the newly developed scoring system and the risk of cut-out. The risk of cut-out increased 8.1 times in individuals with a score of more than 2 (P < .001).

CONCLUSION

Female gender, TAD > 29.45, CalTAD > 31.75, and acceptable or poor reduction quality are the parameters found to be significant in determining the cut-out risk. With the newly developed scoring system, risks can be calculated for all situations that may occur according to the scores obtained by the patients. The cut-out risk increases significantly in patients with a score above 2 points.

LEVEL OF EVIDENCE

Level III, Diagnostic Study.

Is new always better: comparison of the femoral neck system and the dynamic hip screw in the treatment of femoral neck fractures

BACKGROUND

Hip fractures in the elderly population are common and the number of patients is rising. For young and geriatric patients with undisplaced fractures osteosynthesis is the primary type of treatment. The dynamic hip screw (DHS) is around for many years and proved its value especially in displaced fractures. Since 2018 the femoral neck system (FNS) is available as an alternative showing promising biomechanical results. The aim of this study is to evaluate clinical results of the FNS and compare it to the DHS.

MATERIALS AND METHODS

Patients older than 18 years with Garden I-IV fractures that were treated with osteosynthesis in a level 1 trauma center were included in the study. Between January 2015 and March 2021, all patients treated with FNS (1-hole plate, DePuy-Synthes, Zuchwil, Switzerland) or DHS (2-hole plate, DePuy-Synthes, Zuchwil, Switzerland) for proximal femur fractures were included in the study. Closed reduction was achieved using a traction table. All operations were carried out by experienced orthopedic trauma surgeons. Primary outcome measures were rate of implant failure (cut out) and surgical complications (hematoma, infection). Secondary outcome measures were Hb-difference, length of hospital stay and mortality.

RESULTS

Overall, 221 patients were included in the study. 113 were treated with FNS, 108 with DHS. Mean age was 69 ± 14 years. There were 17.2% Garden I, 47.5% Garden II, 26.7% Garden III and 8.6% Garden IV fractures. No difference between the groups for age, body mass index (BMI), Charlson comorbidity index (CCI), time to surgery, Pauwels and Garden classification, rate of optimal blade position or tip apex distance was found. FNS showed lower pre- to postoperative Hb-difference (1.4 ± 1.1 g/l vs. 2.1 ± 1.4 g/l; p < 0.05), shorter operating time (36.3 ± 11.6 min vs. 54.7 ± 17.4 min; p < 0.05) and hospital stay (8.8 ± 4.3 d vs. 11.2 ± 6.8 d; p < 0.05). Surgical complications (FNS 13.3% vs. DHS 18.4%, p > 0.05), rate of cut out (FNS 12.4% vs. DHS 10.2%, p > 0.05) and mortality (FNS 3.5%; DHS 0.9%; p > 0.05) showed no difference between the groups. Logistic regression showed that poor blade position was the only significant predictor for cut out and increased the risk by factor 7. Implant related infection (n = 3) and hematoma/seroma (n = 6) that needed revision was only seen in DHS group.

CONCLUSION

FNS proved to be as reliable as DHS in all patients with hip fractures. Not the type of implant but blade positioning is still key to prevent implant failure. Still due to minimal invasive approach implant related infections and postoperative hematomas might have been prevented using the FNS.

Predictors of and predictive nomogram for cut-out of proximal femur nail anti-rotation device in intertrochanteric fractures

PURPOSE

This study determined independent predictors and developed a predictive nomogram for failed correction of intertrochanteric fractures due to cut-out of the proximal femur nail anti-rotation (PFNA) device.

METHODS

Demographic and radiological data of 592 adult patients with intertrochanteric fractures (AO 31A) treated by PFNA were collected retrospectively. Independent predictors of cut-out were obtained through univariate and multivariate analyses, and a predictive nomogram was established. The discrimination, calibration, and clinical utility of the nomogram were based on receiver operating characteristic curve (AUC), concordance index (C-index), calibration curve, and decision curve analysis, respectively.

RESULTS

Overall, 18 (3.04%) cases of cut-out occurred. Independent predictors according to the multivariate analysis were body mass index (BMI), poor-to-acceptable quality of reduction, PFNA blade position, and tip-apex distance (TAD). AUC of the nomogram was 0.849, and C-index was 0.849 (95% CI [0.844-0.854]). Bootstrapping yielded a corrected C-index of 0.849. The calibration and decision curves indicated good agreement and clinical benefit of the nomogram.

CONCLUSION

A reliable predictive nomogram was developed for cut-out of the PFNA in intertrochanteric fractures, based on BMI, quality of reduction, blade position, and TAD.

Cephalomedullary nailing for reverse oblique intertrochanteric fractures 31A3 (AO/OTA)

INTRODUCTION

Reverse oblique intertrochanteric fractures are classified by the Orthopaedic Trauma Association [OTA]/[AO] as 31A3, and account for up to one-third of all hip fractures, and 2-23% of all trochanteric fractures. The treatment of choice of those fractures is intramedullary nailing as it decreases soft tissue damage and permits early weight bearing.

MATERIAL AND METHODS

A retrospective comparative study was conducted on patients surgically treated for 31A3 fractures from October 2018 to January 2022 in a high-volume regional referral centre. All the patients had been treated with intramedullary nailing.

RESULTS

The selected group included 11 males (16%) and 59 females (84%), with a mean age of 83.6 years (range 61 to 96 years). A Trigen Intertan Nail was the most frequent choice of intramedullary nailing in 33 patients (47%), an Elos Long nail was chosen in 19 cases (27%), while a ZNN nail was used in 18 patients (26%). The mean time between admission and surgery was 2.5 days, with a mean Hb value of 10.5 g/dl reported preoperatively.

CONCLUSION

Patients treated with an Intertan nail reported the lowest TAD, CALTAD, and TALCALTAD mean radiographic values, and the lowest rate of Hb loss and blood transfusions.