A mathematical simulation of the tip-apex distance and the calcar-referenced tip-apex distance for intertrochanteric fractures reduced with lag screws

Factors Associated With Failure of Synthesis in the Treatment of Proximal Femur Fractures With Cephalomedullary Nails

INTRODUCTION

Proximal femur fractures are common in older patients and typically require surgical treatment, with cephalomedullary nails being the gold standard device for this approach. This study aimed to identify the factors associated with the failure of cephalomedullary nailing.

MATERIALS AND METHODS

We retrospectively evaluated 380 patients treated with a cephalomedullary nail between August 2021 and August 2022 in a trauma referral center in Brazil. A total of 221 (58.1%) patients were included in the study after applying specific eligibility criteria. Data were collected and rates were determined by reviewing patients' medical records and radiographs.

RESULTS

Of 221 patients, 14 (6.3%) had nail failures A significant association was found between post-fixation cervico-diaphyseal angle and the occurrence of nail failure (p<0.001). Furthermore, calcar-referenced tip-apex distance (CalTAD) and tip-apex distance (TAD) values were higher in cases with nail failure than in those without nail failure. Cutoff points were established for TAD and CalTAD to measure the correspondence with nail failures.

CONCLUSION

The present study supports previous evidence that varus reduction potentially causes collapse and nail failure in pertrochanteric fractures treated with cephalomedullary nailing and that high TAD and CalTAD values contribute to the incidence of cut-out.

Trochanteric fractures: Tip-Apex distance, Calcar Tip-Apex distance, and Chang criteria-a multiple variable analysis

Failure of osteosynthesis is a common complication of the nailing of trochanteric fractures which typically occurs through form of cut-out. Tip-Apex distance (TAD), Calcar Tip-Apex distance (CalTAD), and Chang criteria are validated variables to predict failure of cephalomedullary nailing. This is a retrospective study which analyzes treatment of trochanteric fractures from 2018 to 2020 (n = 296) evaluating postoperative radiographs and factors of mechanical failure. Our objective was to assess correlation among these variables and their influence on mechanical failure, either individually or creating a new score. Our results support the CalTAD and Chang's criteria as valid predictors of mechanical failure. Furthermore, they empathize the importance of fracture reduction and proper placement of cervical screw. To our knowledge, this is the first study performing multivariate analysis including these 3 variables.

Proposal of a modified tip apex distance for prediction of lag screw cut-out in trochanteric hip fractures

INTRODUCTION

Lag screw cut-out is a serious complication of dynamic hip screw fixation of trochanteric hip fractures. The lag screw position has been acknowledged as one of the important factors affecting the lag screw cut-out. We propose a modification of the Tip Apex Distance (TAD) and hypothesise that it could improve the reliability of predicting lag screws cut-out in these injuries.

MATERIALS AND METHODS

A retrospective study was conducted for hip fracture entries in the period from Jan 2018 to July 2022. A hundred and nine patients were suitable for the final analysis. The modified TAD was measured in millimetres based on the sum of the traditional TAD in the lateral view and the net value of two distances in the AP view, the first distance is from the tip of the lag screw to the opposite point on the femoral head along the axis of the lag screw while the second distance is from that point to the femoral head apex. The first distance is a positive value, whereas the second distance is positive if the lag screw is superior and negative if inferior. A receiver operating characteristic curve was used to evaluate the reliability of the different parameters assessing the lag screw position within the femoral head.

RESULTS

Reduction quality, fracture pattern as per the AO/OTA classification, TAD, Calcar Referenced TAD, Axis Blade Angle, Parker's ration in the AP view, Cleveland Zone 1, and modified TAD were statistically associated with lag screw cut-out. Among the tested parameters, the modified TAD had 90.1% sensitivity and 90.9% specificity for lag screw cut-out at a cut-off value of 25 mm with a P-value < 0.001.

CONCLUSION

The modified TAD had the highest reliability in the prediction of lag screw cut-out. A value ≤ 25 mm could potentially protect against lag screw cut-out in trochanteric hip fractures.

Standardized Tip-Apex Distance (STAD): a modified individualized measurement of cephalic fixator position based on its own femoral head diameter in geriatric intertrochanteric fractures with internal fixation

OBJECTIVE

To design a standardized Tip-Apex Distance (STAD) and analyze the clinical significance of STAD in predicting cut-out in geriatric intertrochanteric fractures with internal fixation.

METHODS

Firstly, we designed STAD according to the rule of TAD. We measured the STAD individually based on its own femoral head diameter (iFHD) instead of the known diameter of the lag screw in calculating TAD, resulting in that the STAD is simply the relative quantitation relationship of iFHD (the times of iFHD). In this study, we assumed that all the iFHD was 6D (1iFHD = 6D, or 1D = 1/6 of iFHD) in order for complete match of the Cleveland zone system, easy comparison of the STAD, and convenient identification for artificial intelligence. Secondly, we calculated and recorded all the STAD of cephalic fixator in 123 eligible ITF patients. Thirdly, we grouped all the ITF patients into the Failure and Non-failure groups according to whether cut-out or not, and analyzed the correlation between the cut-out and the STAD.

RESULTS

Cleveland zone, Parker's ratio (AP), TAD, and STAD were associated with the cut-out in univariate analysis. However, only STAD was the independent predictor of the cut-out by multivariate analysis. No cut-out was observed when STAD ≤ 2D (1/3 of iFHD). The Receiver Operating Characteristic (ROC) curve indicated that STAD was a reliable predictor of cut-out, and the best cut-off value of STAD was 2.92D. Cut-out rate increased dramatically when STAD increased, especially when STAD > 3D (1/2 of iFHD).

CONCLUSION

Essentially, the STAD is a relative quantitation relationship of iFHD. The STAD is a reliable measurement of cephalic fixator position in predicting cut-out in geriatric ITF patients with single-screw cephalomedullary nail fixations. For avoiding cut-out, the STAD should be no more than a half of iFHD.

LEVEL OF EVIDENCE

Level III, Prognostic Study.

Risk factors for cut-outs in geriatric intertrochanteric fractures with cephalomedullary nailing after obtaining acceptable reduction: a case-control study

BACKGROUND

It is irresponsible if we disregard reduction quality to talk about cut-outs in intertrochanteric fractures (ITF) with internal fixation. The aim of this study is to analyze the risk-factors for cut-outs in geriatric ITF with cephalomedullary nailing after obtaining acceptable reduction.

METHODS

In order to investigate the risk-factors for cut-outs in geriatric ITF after obtaining acceptable reduction, we retrospectively reviewed 367 patients who underwent cephalomedullary nail for ITF in our department between September 2016 and December 2021. Potential variables including demographic data and radiological parameters (namely the fracture type, Singh index, lateral wall fracture, cephalic nail position, Parker's ratio index, tip-apex-distance (TAD), and calcar-referenced TAD (CalTAD)) were collected. Logistic regression analysis was performed to identify the significant risk factors for cut-outs.

RESULTS

One hundred twenty-one patients were suitable for this study. Of the 121 cases, nine cases (7.4%) were observed with cut-out or pending cut-out. We found that Age (adjusted odds ratio (OR) 1.158, 95% confidence interval (CI) 1.016 to 1.318, p = 0.028), lateral wall fracture (adjusted OR 11.07, 95%CI 1.790 to 68.380, p = 0.01), and CalTAD (adjusted OR 1.277, 95%CI 1.005 to 1.622, p = 0.045) were independent risk-factors for cut-outs.

CONCLUSIONS

Age, lateral wall fracture and CalTAD are independent risk-factors for cut-outs in geriatric ITF with cephalomedullary nailing after obtaining acceptable reduction. In order to avoid cut-outs, an optimal CalTAD is necessary even obtaining acceptable reduction, especially in the over-aged patients with lateral wall fracture.

CalTAD is the Key Evaluation Tool for Measurement of Cephalic Fixation Position for Predicting Cut-Out in Geriatric Intertrochanteric Fracture Patients with Internal Fixations after Achieving Acceptable Reduction

Objective

To discover the key evaluation tool of the cephalic fixation position for predicting implant failures in geriatric intertrochanteric fracture (ITF) patients treated with internal fixations after achieving an acceptable reduction.

Methods

We measured the geriatric ITF patients undergoing single-screw cephalomedullary nailing (CMN) fixation surgery after obtaining the acceptable reduction (including anatomical reduction and positive medial cortex support reduction) in our treatment group between September 2016 and March 2020 by using four kinds of cephalic fixation position evaluation tools including Cleveland zone system, Parker’s ratio index, tip–apex distance (TAD), calcar-referenced TAD (CalTAD), and analyzed which were the key evaluation tools for measurement of cephalic fixation position for prediction of implant failures in geriatric ITF patients with internal fixations.

Results

Seventy-four ITF patients treated with single-screw CMN fixation after obtaining the acceptable reduction were enrolled in this study. Of the 74 patients, nine cases were observed with implant failures. There were six cases of cut-out and three of pending cut-out. We found that TAD (odds ratio (OR)=1.149; 95% confidence interval (CI), 1.00–1.32; P=.046) and CalTAD (OR=1.140; 95% CI, 1.00–1.30; P=.037) were risk factors for implant failures by univariate analysis, while only CalTAD (OR=1.200; 95% CI, 1.032–1.395; P=.018) was the independent risk factor for implant failures by multivariate analysis. The Kappa coefficient (κ) of CalTAD was .976 (95% CI, .966–.984) by ICC analysis. The ROC analysis showed that the best cut-off value of CalTAD was 23.76 mm with a sensitivity of 77.8% and specificity of 72.3% (area under the curve, AUC =.775; P = .001).

Conclusions

CalTAD is the key evaluation tool for measurement of cephalic fixation position for predicting implant failures in geriatric ITF patients treated with single-screw CMN after obtaining the acceptable reduction.

Early prediction of implant failures in geriatric intertrochanteric fractures with single-screw cephalomedullary nailing fixation

OBJECTIVE

The implant failures of intertrochanteric fractures (ITF) after single-screw cephalomedullary nailing (CMN) were multifactorially associated with various related factors. However, a comprehensive scoring system for the early prediction of implant failures is still lacking. Thus, this study aims to establish a quantification scoring system (QSS) and verify whether the QSS is reliable for predicting implant failures in geriatric ITF patients.

METHODS

We established the QSS of geriatric ITF with single-screw cephalomedullary nailing within three days after surgery. The QSS included eight points totally at eight parameters, including bone quality, fracture type, reduction quality, and internal fixation placement. Then we retrospectively analyzed seventy-seven ITF (seventy-six patients) with surgical treatment between October 2016 and July 2020 in our hospital to verify whether the QSS scoring is suitable for predicting implant failures in ITF patients.

RESULTS

Implant failures were in fifteen fractures (fifteen patients), including six cases of cut-out, eight of pending cut-out, and one of cut-through. There were three cases with 2 points in QSS, three with 3 points, five with 4 points, four with 5 points in these fifteen fractures. No fractures were with 1 point in QSS, and no implant failures when scoring over 5 points in QSS. Except for QSS scoring, no significant difference was in the collected data by binary logistic regression analysis. QSS scoring was significantly associated with implant failures (Adjusted odds ratio (OR) = 7.312; 95% confidence intervals (CI), 2.561 to 20.871; p < 0.001). In the analysis of Spearman's correlation, there was a strong correlation between QSS scoring and the occurrences of implant failures (RQSS = -0.964, p < 0.001). The ROC result indicated that QSS was reliable in predicting implant failures at the cut-off of 5 points (AUC (the area under the curve) = 0.944; 95% CI, 0.866 to 0.983; p < 0.001).

CONCLUSION

The QSS is a useful early prediction of implant failures in geriatric ITF with cephalomedullary nailing fixation. QSS scoring more than 5 points can effectively reduce the risk of implant failures.

Low filling ratio of the distal nail segment to the medullary canal is a risk factor for loss of anteromedial cortical support: a case control study

Background

Anteromedial cortical support apposition (positive and/or neutral cortical relations) is crucial for surgical stability reconstruction in the treatment of trochanteric femur fractures. However, the loss of fracture reduction is frequent in follow-ups after cephalomedullary nail fixation. This paper aimed to investigate the possible predictive risk factors for postoperative loss of anteromedial cortex buttress after nail fixation.

Methods

A retrospective analysis of 122 patients with AO/OTA 31A1 and A2 trochanteric femur fractures treated with cephalomedullary nails between January 2017 and December 2019 was performed. The patients were classified into two groups according to the postoperative status of the anteromedial cortical apposition in 3D CT images: Group 1 with contact “yes” (positive or anatomic) and Group 2 with contact “No” (negative, loss of contact). The fracture reduction quality score, tip-apex distance (TAD), calcar-referenced TAD (Cal-TAD), Parker ratio, neck-shaft angle (NSA), and the filling ratio of the distal nail segment to medullary canal diameter in anteroposterior (AP) and lateral fluoroscopies (taken immediately after the operation) were examined in univariate and multivariate analyses. Mechanical complications were measured and compared in follow-up radiographs.

Results

According to the postoperative 3D CT, 84 individuals (69%) were categorized into Group 1, and 38 individuals (31%) were classified as Group 2. The multivariate logistic regression analysis showed that the poor fracture reduction quality score (P < 0.001) and decreasing filling ratio in the lateral view (P < 0.001) were significant risk factors for the loss of anteromedial cortical contact. The threshold value for the distal nail filling ratio in lateral fluoroscopy predicting fracture reduction re-displacement was found to be 53%, with 89.3% sensitivity and 78.9% specificity. The mechanical complication (varus and over lateral sliding) rate was higher in Group 2.

Conclusions

The fracture reduction quality score and the decreasing filling ratio of the distal nail to the medullary canal in the lateral view (a novel parameter causing pendulum-like movement of the nail) were possible risk factors for postoperative loss of anteromedial cortical support.

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

Cut-out is one of the most common mechanical failures in the internal fixation of trochanteric hip fractures. The tip-apex distance (TAD), and the calcar-referenced tip apex distance (CalTAD) are the radiographic parameters that most predict the risk of cut-out. The optimal CalTAD value has not yet been defined, but the optimal TAD value is reported as 25 mm or less. However, this cut-off is highly specific but poorly sensitive. The aim of this study was to determine highly specific and sensitive TAD and CalTAD values and shed light on the role of other clinical variables. A total of 604 patients were included in this retrospective cross-sectional study. For each patient the following data were recorded: number of cut-out, AO/OTA classification, quality of the reduction, type of nail, cervicodiaphyseal angle, type of distal locking, post-operative weight-bearing, TAD and CalTAD values, and the position of the screw head in the femoral head according to the Cleveland system. The incidence of cut-out across the sample was 3.1%. The median TAD in the cut-out group was 38.72, while in the no cut-out group it was 22.16. The median CalTAD in the cut-out group was 39.34, while in the no cut-out group it was 22.19. The cut-off values for TAD and CalTAD with highest value of sensitivity and specificity for the risk of cut-out were 34.8 and 35.2, respectively. The incidence of cut-out can be reduced by performing careful minimal reduction and ensuring stable fixation by avoiding TAD > 34.8 mm and CalTAD > 35.2 mm.

The safety and accuracy of the fluoroscopic imaging during proximal femoral fixation: A computerized 3D reappraisal of the joint penetration risk

BACKGROUND

To assess the success of proximal cephalomedullary nailing operations for treating trochanteric fractures, surgeons utilize 2D fluoroscopy to observe the relative positions of the femoral head and the implant. One distance-based risk parameter, observed from the AP and Lateral projections, is the Tip-Surface Distance(TSD) that dictates how close to the outer cortex should the implant tip be residing to avoid post-surgical complications such as cut-out or joint penetration. In this study, the safety and the accuracy of the orthogonal fluoroscopic imaging were evaluated.

METHODS

A femoral head model was created and the risk zone was defined as a hemispherical shell of 5 mm thickness beneath the subchondral cortex, which should not be violated during screw insertion. The remaining hemisphere beneath the risk zone was designated as the safe zone. To assess the effect of head size, each simulation was conducted for 34, 47, and 60 mm diameter(D_femur) femoral heads. The rate of safe zone violation was calculated for all possible screw endpoints with a TSD of at least 5 mm on fluoroscopic orthogonal views (TSD_AP and TSD_Lat).

RESULTS

The minimum risk of joint penetration was achieved when the TSD_AP/TSD_Lat ratio was 1. For D_femur of 34 mm there was a risk of 91.7% of the safe zone violation when each TSD_AP and TSD_Lat were 5 mm and 0% for 9 mm. For D_femur of 47 mm, the risk was 92.2% for 5 mm and 0% for 11 mm. For D_femur of 60 mm, the risk was 92.3% for 5 mm and 0% for 13 mm. Safety maps were constructed for all possible TSD combinations for 34, 47, and 60 mm femoral heads.

CONCLUSIONS

Depending solely on the orthogonal fluoroscopic images is not a safe and accurate technique for assessing joint penetration risk during proximal femoral fixation due to the spherical geometry of the femoral head. The screw tip can lie completely outside of the femoral head even when it appears inside, in both orthogonal fluoroscopic views. Evidently, when using TSD, more stringent distance limits should be chosen, contrary to the recommended 5 mm limit. Our safety maps for TSD combinations may be used to check the security of the implantation.

[Comparison of the predictive value of tip-apex distance and calcar referenced tip-apex distance in treatment of femoral intertrochanteric fractures with Asian type proximal femoral nail fixation]

Objective

To compare the predictive value of the two concepts for complications by comparing the incidences of surgical complications associated with different tip-apex distance (TAD) and calcar referenced tip-apex distance (Cal-TAD) in the treatment of femoral intertrochanteric fractures with Asian type proximal femoral nail (APFN) fixation.

Methods

A total of 188 cases of femoral intertrochanteric fractures treated with APFN fixation between January 2014 and December 2018 were collected according to inclusion criteria. TAD and Cal-TAD were measured on the X-ray film at immediate after operation; the patients were divided into two groups according to the measurement results: <25 mm and ≥25 mm. Gender, age, and fracture side and AO type were recorded. The patients in each group were reviewed whether there was delayed fracture union or nonunion, whether the screw blade moved axially, whether the femoral neck collapsed or even screw blade cut out, whether the internal fixator became loose or broken within 12 months after operation. Then statistical analysis was performed.

Results

There were 119 patients with TAD<25 mm and 69 patients with TAD≥25 mm, and 142 patients with Cal-TAD<25 mm and 46 patients with Cal-TAD≥25 mm. There was no significant difference in gender, age, or fracture side and AO type between groups ( P>0.05). During the follow-up, 6 patients (5.04%) with TAD<25 mm, 10 patients (14.49%) with TAD≥25 mm had complications, and 1 patient (0.70%) with Cal-TAD<25 mm and 15 patients (32.61%) with Cal-TAD≥25 mm had complications. There were significant differences in the incidence of complication between the patients with different TAD, between the patients with different Cal-TAD, and between patients with TAD<25 mm and Cal-TAD<25 mm ( P<0.05).

Conclusion

In the operation of femoral intertrochanteric fracture with APFN fixation, surgical complications can be significantly reduced when TAD or Cal-TAD was controlled within 25 mm, Cal-TAD is more significant in the prediction of postoperative complications.

A novel lower bound for tip-apex distance

PURPOSE

The cut-out of the cephalomedullary nail is among the most common post-surgery complications for intertrochanteric fractures. As a risk predictor, a tip-apex distance (TAD) below 25 mm, observed from orthogonal fluoroscopic views, is recommended in the literature. This study aims to demonstrate that TAD < 25 mm is a mathematically insufficient risk definition and to complement the TAD upper bound with an appropriate lower bound, with the introduction of a novel distance parameter, TADX, based on the orthogonal projection of the nail tip on the central femoral midline.

METHOD

Through a mathematical simulation software, all the possible points that lie inside the AP and lateral views of the proximal femoral hemisphere are utilized to create a 3D grid that is sorted into geometrically safe and risk-bearing regions. Extending this methodology, TAD < 25 mm, 10 mm < TAD < 25 mm, and the ideal tip position volumes are simulated. Finally, intersection volumes are created by a combination of different candidate lower TADX bounds and TAD < 25 mm upper bound to determine satisfactory TADX limits.

RESULTS

Simulation of TAD-bound zones exposed that TAD is only a mathematically suitable parameter for defining the upper boundary but not the lower boundary for the optimal region. However, using a TADX lower limit creates a 3D volume that is much closer to the optimal tip region volumetrically and can still be as quickly calculated from 2D AP and lateral views.

CONCLUSIONS

According to the mathematical simulations, the use of a TADX lower bound of 9 mm for small, 7.5 mm for medium, and 7 mm for large femoral heads in conjunction with a TAD upper bound of 25 mm is suggested.

How to get better TAD? Relationship between anteversion angle of nail and position of femoral neck guide pin during nailing of intertrochanteric fractures

Background

To demonstrate the correlation between guide pin-shaft angle (PSA) at the anteroposterior film and anteversion angle of guide pin at the lateral film and investigate whether excellent tip–apex distance (TAD) can be obtained by changing the entry point via axial rotation of the main intramedullary nail.

Methods

Fifty patients with intertrochanteric femoral fractures (IFFs) undergoing internal fixation with intramedullary nails under 2D fluoroscopy were retrospectively enrolled. Both of the PSA at the anteroposterior film and anteversion angle at the lateral film before and after adjustment of the guide pin were collected. Pearson correlation analysis was performed to investigate their correlation. Intraoperative and postoperative outcomes were recorded. Furthermore, the software of Mimics 10.0 and Pro/E were used to establish the 3D models of the proximal femur and main intramedullary nail/guide pin, respectively. Surgery was simulated on the Pro/E software platform and solid geometry analysis was conducted to calculate the correlation between the PSA and the anteversion angle.

Results

Pearson correlation analysis indicated there was a positive correlation between PSA and anteversion angle, with the correlation coefficient of 0.902 (p < 0.01). By altering the PSA and anteversion angle, TAD was adjusted to be less than 25 mm in all patients. The mean operative time, fluoroscopy time and length of hospital stay were 65.82 ± 11.16 min, 2.03 ± 0.79 min and 6.66 ± 2.49 d. Thirty-one patients received blood transfusions (3.55 ± 1.95 U). Fracture reduction was considered to be good or acceptable in all patients. Complications occurred only in 6 patients (12.00%). At a 3-month follow-up, the mean Timed Up and Go was 31.54 ± 20.95 s and Harris Hip Score was 72.88 ± 8.79. The 3D surgery model also showed when the main intramedullary nail was externally rotated or internally rotated of 20° at the standard location, the PSA of guide pin at the anteroposterior position and anteversion angle of the guide pin at the lateral position were simultaneously increased or decreased.

Conclusion

Our findings suggest altering the PSA and anteversion angle may be beneficial for obtaining excellent TAD and achieving superior outcomes.

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.

Traditional distance "tip-apex" vs. new calcar referenced "tip-apex" - which one is the best peritrochanteric osteosynthesis failure predictor?

INTRODUCTION

In the treatment of trochanteric fractures, the distance between the tip of the screw and the apex of the femoral head or tip-to-apex distance (TAD) was popularized by Baumgaertner about 20 years ago as an important predictor of failure. Recently, a new reference point for determining the apex has been advocated. In this new calcar tip-to-apex (calTAD) the femoral head apex is referenced to the femoral calcar and not the center of the neck. The aim of this study is to evaluate which of these two indexes is better in predicting failure of pertrochanteric fracture fixation.

MATERIALS AND METHODS

We conducted a retrospective study focusing on pertrochanteric fractures operated in our institution between 2010-2013. Radiographic measurement of both indexes was performed. Demographic information, as well as several variables with recognized influence on the rate of failure, were collected. Finally, logistic regression analysis was used to identify variables independently associated with fixation failure.

RESULTS

A total of 463 pertrochanteric fractures were operated during this time period. One hundred and seventy cases were excluded because of early loss of follow-up (n = 143) or inadequate fluroscopic imaging (n = 27) control precluding accurate measurements. Two hundred and ninety-three fractures were included. Traditional TAD and calTAD were significantly different in the failure group: 24.9 vs. 18.0 mm (p < 0.001) and 29.2 vs. 22.6 mm (p < 0.001) respectively. No other registered variable was significantly different. Multivariate analysis confirms traditional TAD (p = 0.003; OR = 1.10) and calTAD (p = 0.002; OR = 1.12) as independent risk factors for failure.

DISCUSSION/CONCLUSION

Both the traditional TAD and the new calTAD have shown to be relevant indexes and independently predictive of the likelihood of failure of pertrochanteric fracture fixation. Interestingly, we found the optimal threshold for the traditional TAD to be lower (<20 mm) than the traditional cutoff (<25 mm). Our study did not confirm calTAD to be superior to the traditional TAD. From the surgical practice point of view, the authors argue that the ideal position of the screw is the central region of the femoral head (minimal traditional TAD). In case of deviation, it must be infero-central in order to maintain a low calTAD thus minimizing the risk of fixation failure.

[The migration of helical blade and the tip apex distance value in cephalomedullary nail for geriatric intertrochanteric fractures]

Objective

To investigate the association between the tip apex distance (TAD) and migration of helical blade in the femoral head of geriatric intertrochanteric fractures.

Methods

A retrospective study of intertrochanteric fractures treated with the proximal femoral nail antirotation (PFNA) between June 2015 and June 2018 was performed. There were 32 males and 55 females with an average age of 84.7 years (range, 80-101 years). All of them were unilateral fresh closed intertrochanteric fractures caused by low energy injury. According to AO/Orthopaedic Trauma Association (AO/OTA) classification, 33 cases belonged to type 31-A1, 35 cases to type 31-A2, and 19 cases to type 31-A3. The time interval from injury to operation was 1-16 days (mean, 3.7 days). The TAD was measured according to immediate postoperative X-ray films. The cases were divided into two groups: group A with TAD less than 20 mm and group B with TAD greater than 20 mm. The difference of fracture healing and migration of helical blade between the two groups were observed.

Results

According to the TAD value immediately after operation, 49 patients in group A had TAD of 8.9-19.7 mm, with an average of 18.6 mm; 38 patients in group B had TAD of 20.1-41.4 mm, with an average of 27.7 mm. The 87 patients were followed up for an average of 11.7 months, ranging from 4 to 28 months. Three cases (all in group B) underwent screw blade cutting and displacement, which resulted in internal fixation failure, including 1 case with femoral head cut upward and 2 cases with femoral head penetrated inward. The remaining 84 cases had bone healing without internal fixation related complications such as fracture of internal fixator and fracture of femoral shaft. There was significant difference in the incidence of internal fixation failure between group A and group B ( P=0.049).

Conclusion

Reducing the TAD value of helical blade appropriately (15-20 mm) in PFNA internal fixation for intertrochanteric fracture patients over 80 years old can increase initial stability without increasing the risk of helical blade migration.

A novel angle on helical blade placement in trochanteric fractures - The axis-blade angle

INTRODUCTION

For trochanteric fractures, helical blade placement is crucial to the prognosis of operations. Existing measurement methods used for blade placement include the Cleveland zone, the tip-apex distance (TAD), the calcar-referenced tip-apex distance (CalTAD), and the Parker's ratio. These methods all lack a direct view on blade direction. The current study proposed the axis-blade angle (ABA) to solve direction problem and investigated its clinical applicability.

METHODS

A retrospective study collected 156 patients between May 2014 and February 2018. The occurrence of mechanical complications was analyzed in relation to age, gender, fracture side, American Society of Anesthesiologists classification, fracture classification, reduction quality, bone quality, the Cleveland zone, the Parker's ratio, the TAD, the CalTAD, and the ABA.

RESULTS

119 patients, including 25 with mechanical complications, were suitable for full analysis. In the univariate analysis, the Cleveland zone, reduction quality, the TAD, the CalTAD and the ABA were statistically associated with mechanical complications. In the multivariate analysis, reduction quality (p = 0.008) and the ABA (p < 0.001; adjusted OR 0.86;95% CI 0.77 to 0.96) showed significant results, which indicated that reduction quality and the ABA were two independent influencing factors for mechanical complications. Calculation of the receiver operating characteristic (ROC) curve indicated that the ABA was a reliable predictor of mechanical complications at the cut-off of -10°.

CONCLUSIONS

The ABA provides instruction for the intraoperative adjustment of guide wire direction. Placing the helical blade with an ABA > -10° can effectively reduce the risk of mechanical complications.

Is calcar referenced tip-apex distance a better predicting factor for cutting out in biaxial cephalomedullary nails than tip-apex distance?

PURPOSE

To test the significance of calcar referenced tip-apex distance (CalTAD) and the length of anti-rotation screw (AR screw) as predictors for failure after biaxial cephalomedullary (CM) nailing of intertrochanteric fractures.

METHODS

We retrospectively reviewed 190 consecutive fractures that had undergone biaxial CM nailing. Of these, 67 met the inclusion criteria of a non-pathological fracture with a minimum of 90 days radiological follow-up (mean 458 days; 91 days to 4.9 years).

RESULTS

The overall failure rate was 15% (10 of 67). Failure was associated with a higher CalTAD in most of the patients (13%, p < 0.001). A higher tip-apex distance (TAD) was not significantly associated with failure ( p = 0.132), when the CalTAD was less than 25 mm. When the AR screw length exceeded a line connecting the tip of the nail and the lag screw, screw cutout occurred only in one patient ( p = 0.095).

CONCLUSION

Our data provide the first reported clinical evidence that the CalTAD is a better predictor of cutout in biaxial CM nailing than TAD measurement. However, the length of anti-rotational element does not seem to be an independent predictor of CM nailing failure.

A retrospective analysis of the InterTan nail and proximal femoral nail anti-rotation in the treatment of intertrochanteric fractures in elderly patients with osteoporosis: a minimum follow-up of 3 years

BACKGROUND

The study aims to compare the long-term functional and radiographic outcomes of two devices for the treatment of primary intertrochanteric fractures (IFs, OTA 3.1A2.1-A2.3) in elderly patients with osteoporosis.

METHODS

Between December 2010 and August 2014, 332 elderly osteoporosis patients with IFs (OTA 3.1A2.1-A2.3) fixed by an InterTAN nail (IT) or a proximal femoral nail anti-rotation (PFNA) device were retrospectively evaluated. Follow-up occurred 1, 3, 6, and 12 months postoperatively and every year thereafter. Mortality was recorded. Patient-related functional and radiographic outcomes were compared. The primary endpoint was the long-term radiographic outcomes. The secondary endpoint was the long-term functional outcomes.

RESULTS

A total of 283 patients (283 hips) with osteoporosis (IT, n = 144; PFNA, n = 139) were evaluated with a mean follow-up period of 38.8 months (range, 36-43 months). No between-group significant differences were noted in the patient demographics, operation variables, and postoperative Harris Hip Score. More radiographic complications were noted in terms of screw cut-out, femoral shaft fracture distal or around the tip of the main nail, and varus collapse of the femoral head in the PFNA group compared with that in the IT group (P < 0.05).

CONCLUSION

For osteoporotic IFs (OTA 3.1A2.1-A2.3) in elderly patients, the use of IT aids in decreasing radiographic complications, but the between-group functional outcomes showed no significant difference.

Anteromedial cortical support reduction in unstable pertrochanteric fractures: a comparison of intra-operative fluoroscopy and post-operative three dimensional computerised tomography reconstruction

PURPOSE

Anteromedial cortical support reduction is favourable for secondary stability after limited sliding in unstable pertrochanteric fractures. The aim of this study was to compare the accuracy and agreement between intra-operative fluoroscopy and post-operative 3D reconstruction.

MATERIALS AND METHODS

A retrospective analysis of 28 patients (mean 81.6 years) treated with short cephalomedullary nails was performed. All patients had full sets of intra-operative fluoroscopy and post-operative 3D CT images. Observation was focused on the position of the anteromedial cortices of the inferior corner between the head-neck fragment and femoral shaft, and their relationship was categorised into three types: positive, neutral and negative. The percentage of subsequent changes in cortical reduction quality between fluoroscopy and 3D CT was calculated and compared.

RESULTS

There were 24 positive (85.7%), four neutral and no negative positions in the anteroposterior (AP) view and one positive, 20 neutral (71.4%) and seven negative positions in the lateral view from fluoroscopy. On post-operative 3D CT images with a full range of rotation, definitive anteromedial cortical contact (positive and neutral support) was observed in 18 cases (64.3%). Ten cases lost the anteromedial cortical buttress. With the posteromedial region of the lesser trochanter detached, a positive AP cortical position combined with a positive/neutral lateral position on fluoroscopy (17 cases) was highly predictive of reliable, definitive cortical support (15 cases, 88.2%) on 3D CT. A negative lateral position on fluoroscopy (seven cases), regardless of the combination in the AP view, was likely to predict the final loss of cortical support (six cases, 85.7%) on 3D CT; a positive/neutral lateral position (21 cases) was only associated with loss of support in four cases (19.1%) (p < 0.05).

CONCLUSIONS

A lateral negative position of the anterior cortex on fluoroscopy for unstable pertrochanteric fractures may be highly predictive of post-operative final loss of the anteromedial cortical buttress, which should be avoided during operation.

A six-year retrospective analysis of cut-out risk predictors in cephalomedullary nailing for pertrochanteric fractures: Can the tip-apex distance (TAD) still be considered the best parameter?

OBJECTIVES

Intramedullary fixation is considered the most stable treatment for pertrochanteric fractures of the proximal femur and cut-out is one of the most frequent mechanical complications. In order to determine the role of clinical variables and radiological parameters in predicting the risk of this complication, we analysed the data pertaining to a group of patients recruited over the course of six years.

METHODS

A total of 571 patients were included in this study, which analysed the incidence of cut-out in relation to several clinical variables: age; gender; the AO Foundation and Orthopaedic Trauma Association classification system (AO/OTA); type of nail; cervical-diaphyseal angle; surgical wait times; anti-osteoporotic medication; complete post-operative weight bearing; and radiological parameters (namely the lag-screw position with respect to the femoral head, the Cleveland system, the tip-apex distance (TAD), and the calcar-referenced tip-apex distance (CalTAD)).

RESULTS

The incidence of cut-out across the sample was 5.6%, with a higher incidence in female patients. A significantly higher risk of this complication was correlated with lag-screw tip positioning in the upper part of the femoral head in the anteroposterior radiological view, posterior in the latero-lateral radiological view, and in the Cleveland peripheral zones. The tip-apex distance and the calcar-referenced tip-apex distance were found to be highly significant predictors of the risk of cut-out at cut-offs of 30.7 mm and 37.3 mm, respectively, but the former appeared more reliable than the latter in predicting the occurrence of this complication.

CONCLUSION

The tip-apex distance remains the most accurate predictor of cut-out, which is significantly greater above a cut-off of 30.7 mm.Cite this article: G. Caruso, M. Bonomo, G. Valpiani, G. Salvatori, A. Gildone, V. Lorusso, L. Massari. A six-year retrospective analysis of cut-out risk predictors in cephalomedullary nailing for pertrochanteric fractures: Can the tip-apex distance (TAD) still be considered the best parameter?. Bone Joint Res 2017;6:481-488. DOI: 10.1302/2046-3758.68.BJR-2016-0299.R1.