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.

One year "ADAPT system" use for proximal femoral fracture osteosynthesis with intramedullary nail . A case control study.

Introduction: Proximal femoral fractures (PFF) are a significant health concern among the elderly, often leading to complications and high mortality rates. Intramedullary nailing is widely considered the most effective treatment for lateral proximal femoral fractures (LPFF), with the Tip Apex Distance (TAD) being a crucial predictor of surgical success. This study aimed to compare outcomes between patients treated with and without the ADAPT (ADAptive Positioning Technology) system, which aids in the precise placement of the cephalic screw. Materials and Methods: A retrospective analysis was conducted on 97 patients with intertrochanteric fractures treated in 2022. Patients were divided into two groups: those treated with the ADAPT system (group I, n=34) and those treated without it (group II, n=63). Fractures were classified according to AO/OTA classification. The primary outcomes measured were operative time, cephalic screw angle, TAD, and incidence of lag screw cut-out. Statistical analyses included chi-square tests and t-tests, with significance set at P < 0.05. Results: The ADAPT system did not significantly reduce TAD (18.21 mm in the ADAPT group vs. 19.94 mm in the control group, p=0.149). Operative times were similar between the groups. The incidence of lag screw cut-out was low in both groups, with no significant differences. The study confirmed a strong correlation between higher TAD and increased risk of screw cut-out, underscoring the importance of precise screw placement. Discussion: Computer-assisted surgery, such as the ADAPT system, aims to enhance the accuracy of cephalic screw placement. In this study, the ADAPT system didn't demonstrate a statistically significant advantage in reducing TAD or preventing screw cut-out. Nevertheless, the critical role of TAD in preventing fixation failure was reaffirmed, emphasising the need for precise surgical techniques. Conclusion: While the ADAPT system did not show a significant advantage in reducing TAD or preventing screw cut-out in this study, the importance of achieving optimal TAD in cephalomedullary nailing was reinforced. Future research should continue to explore the role of computer-assisted systems in enhancing surgical accuracy and improving outcomes for patients with LPFF.

A dual telescoping lag screw nailing system for intertrochanteric fractures: retrospective analysis of clinical and radiologic outcomes.

BACKGROUND AND PURPOSE: The aim of this study was to evaluate whether this system is associated with a reduced rate of failure and complications in patients treated for proximal femoral fractures with intramedullary nailing. MATERIALS AND METHODS: 742 Patients with AO-OTA 31-A intertrochanteric fractures were enrolled at a single Institution. Functional evaluation was assessed through the Functional Independence Measure (FIM™) instrument and Parker's New Mobility Score (NMS). Radiological follow-up included the degree of the reduction according to the Baumgartner criteria, the Tip-Apex Distance, and the shortening of the telescoping screws and its lateral protrusion. RESULTS: Pre-operative mean FIM™ and NMS were 4.3 (range 1-9) and 98.7 (range 22-126), respectively. At the 12-month follow-up the average FIM™ and NMS were 95.3 (range 22-126) and 3.7 (range 1-9), respectively. Mean shortening of the lag screws was 4.3 mm (range 1-8) and mean lateral protrusion was 1.7 mm (range 0-3). 3 Cases (0.70%) of non-consolidation requiring reoperation were recorded. 1 Case (0.24%) of these cases was also characterized by nail breakage. No case of cut-out has been reported at our follow-up. CONCLUSIONS: This dual telescoping nail system is effective and safe. The sliding of the telescoping screws within the barrel is able to decrease strain from the femoral head during weight bearing reducing the risk of cut-out.

Correlation between cephalic screw positioning of Standard Gamma 3 Nail for intertrochanteric fractures and cut-out incidence.

INTRODUCTION: Lateral fractures of proximal femur are the most frequent fractures in elderly people. Internal fixation using medullary nails is the gold standard of treatment (Gamma 3 nail is the most implanted device) due to reduced incidence of complications than other devices. We report our experience in treating this kind of fractures with Gamma 3 nail, between January 2015 and December 2021. METHODS: We performed a retrospective cohort study of patients treated in our orthopaedic department; level of clinical care is III: 559 patients (431 females and 128 males, with an average age of 85.3 years) with lateral femoral neck fracture. All patients were surgically treated with Gamma 3 standard nail (SGN). We evaluated preliminary X-rays to classify fractures, according to AO-OTA classification and post-operative X-ray to verify cephalic screw position site, according to areas described by Cleveland in 1959: we measured tip-to-apex distance (TAD) and tip-to-apex calcar referred distance (CalTAD). Finally Chang reduction quality criteria (CRQC) for fracture reduction of trochanteric fractures were determined using preoperative or postoperative Antero-Posterior (AP) and lateral radiographs in a Picture Archiving and Communication System (PACS). Incidence of cut-out was evaluated in relation with these parameters. Patients were divided into 2 groups: first group had cephalic screw in optimal positions (5-8-9), the other group had cephalic screw in other positions. RESULTS: In 328 patients (58.7%) screw was in positions 5-8-9, in 231 patients (41.2%) screw was in not-optimal position. Median TAD was 19.1 ± 7.0 mm (range = 0.0-50.5); in 463 patients (82.8%) TAD was ≤ 25 mm. Median CalTAD was 21.4 ± 4.7 mm (range = 5.7-39.2); in 105 patients (79.4%) CalTAD was ≤ 25 mm. Cut-out was observed in 8 cases (1.43%). Multivariate analysis showed a significant correlation (p < 0,05) between incidence of cut-out and fracture type 31A2 and with TAD values >25 mm. Cephalic screw position did not influence incidence of cut-out. DISCUSSION: In order to obtain fracture healing with a low risk of failure, in particular cut-out, it is necessary to obtain good reduction of fracture and optimal lag screw position in order to achieve a TAD inferior to 25 mm.

Applying Characteristic Impedance Compensation Cut-Outs to Full Radio Frequency Chains in Multi-Layer Printed Circuit Board Designs.

Modern wireless communication systems are of utmost importance to various sectors such as healthcare, education, the household, and the advancement of emerging technologies like the internet of things, autonomous vehicles, and the enhancement of 5G. Further development and improvement of these systems drives the need for small dimension, high integration and density, and cost-effective electronic devices. Achieving optimal performance in wireless electronic devices involves overcoming engineering challenges related to microstrip line signal integrity. This research addresses the impact of surface mount technology (SMT) component pads on signal integrity, proposing a novel high-frequency microstrip line structure for mitigating impedance discontinuities. The study introduces stepped microstrip lines and explores characteristic impedance compensation techniques. A six-layer printed circuit board (PCB) structure is presented, and the effects of compensation on signal integrity are analyzed using time-domain reflectometry and scattering parameter measurements. The results demonstrate the effectiveness of compensation methods in aligning characteristic impedance with desired values, thereby ensuring improved impedance matching and transmission coefficients. The average over-the-length impedance for the proposed structure with compensation applied was measured to be 52.7 Ω, which is only 1.3 Ω (2.5%) more than that of the reference microstrip. Applying reference plane cut-outs leads to a maximum compensated absolute value of more than 30 Ω to reach the target impedance with a 10% tolerance. This research contributes valuable insights for advancing wireless communication systems and maintaining robustness in high-frequency microstrip transmission lines.

Failure after intramedullary nailing for geriatric trochanteric fracture: does quality of fracture reduction on the AP and lateral planes show the same results?

PURPOSE: This study aimed to investigate the failure of trochanteric fracture fixation according to the quality of fracture reduction on the anteroposterior (AP) and lateral views. METHODS: Data from 340 female and 152 male patients ≥ 60 years of age who underwent intramedullary nailing for a trochanteric fracture between 2016 and 2020 were analysed retrospectively. The quality of fracture reduction was classified as type A, type E, and type I on the AP view and type N, type A, and type P on the lateral view according to the relative position of the proximal and distal fragments. The failure rate was evaluated and compared according to the quality of fracture reduction. The risk factors of the fixation failure were investigated by comparison of variables between patients with and without failure and by regression analysis. RESULTS: Patients with poor reduction, type I and type P had higher failure rates. However, a statistically significant difference was found only for patients with poor reduction (type P) on the lateral view (p < 0.001). Patients with failure showed significantly higher rates of poor reduction on the lateral view and AO/OTA type A3 fractures. The regression analysis also showed that poor reduction on the lateral view (odds ratio [OR] 12.70; 95% confidence interval [CI] 4.0-40.6; p < 0.001) and AO/OTA type A3 fractures (OR 5.40; 95% CI 1.24-23.49, p = 0.025) were risk factors for failure. CONCLUSION: Poor reduction such as type P reduction was associated with failure after intramedullary nailing for trochanteric fractures. Surgeons should check the quality of fracture reduction carefully with the proper fluoroscopic view to prevent failure in geriatric patients with trochanteric fractures.

Augmented versus non-augmented Trochanteric Fixation Nail-Advanced (TFNA) nails for treating trochanteric fractures in patients over sixty-five years of age.

PURPOSE: Intramedullary nailing is a common treatment for pertrochanteric fractures. However, implant-related mechanical failures, such as cut-out and cut-through, lead to higher rates of revision surgery, loss of autonomy, and mortality. Cemented augmentation enhances the bone-implant interface. This study compared the frequency of mechanical failures between augmented and non-augmented Trochanteric Fixation Nail-Advanced (TFNA) nails. METHODS: This descriptive, retrospective study at a level 1 trauma centre included patients aged > 65 years with pertrochanteric fractures treated by a short augmented or non-augmented TFNA nail. The primary outcome was the comparison of cut-out or cut-through rates between groups at three and six months postoperatively. RESULTS: Of the 181 patients analysed, 103 had augmented TFNA nails and 78 had non-augmented TFNA nails. There were no statistically significant differences between groups in terms of demographic characteristics, AO/OTA classification, or quality of reduction. The failure rate was significantly lower in the augmented group than in the non-augmented group: 1 (0.97%) versus 9 (11.54%) (p = 0.005). At six months postoperatively, there was no significant difference between the two groups concerning functional recovery, as measured by the Parker and EuroQoL 5-Dimensions scores. CONCLUSIONS: For patients aged over 65 years, the use of the augmented TFNA nail may reduce the risk of fixation failures such as cut-out.

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.

Experimental and numerical analysis of the influence of intramedullary nail position on the cut-out phenomenon.

BACKGROUND AND OBJECTIVE: Proximal femur fractures, colloquially known as hip fractures, are a common pathology with increasing incidence in the last years due to the enhanced ageing population. Regarding the extracapsular fracture, the treatment for this pathology consists of a fixation of the fragments using an osteosynthesis device, mainly the intramedullary nail. This repairing method implies several complications, which may include the failure of the fixation device, frequently occurring due to the "cut-out" mechanism. The present work focuses on the study of how the position of the cephalic screw, which should be fixed during surgery, affects the cut-out risk. Through experimental tests and numerical models some variables that can be critical for the cut-out phenomenon are analysed. METHODS: This study has been carried out through a numerical model based on the finite element method and experimental tests. The digital image correlation technique has been used in experimental tests to measure displacements on the femoral surface with the objective of numerical model validation. Some basic daily activities with different intramedullary nail positions have been analysed through the numerical model, considering variables that can induce the cut-out complication. RESULTS: The results show how the intramedullary nail position clearly influences the cut-out risk, showing that displacements in the upper, anterior and posterior direction increase the cut-out risk, while displacement in the lower direction endangers the intramedullary nail itself. Thus, the centred position is the one which reduces the cut-out risk. CONCLUSIONS: This work supposes an improvement in the knowledge of the cut-out phenomenon thanks to the combination of experimental testing and validated numerical models. The effects of different intramedullary nail positions in the femoral head are studied, including a novelty variable as torque, which is critical for the structural integrity of the fixation. The main conclusion of the work is the determination of the central intramedullary nail position as the most favourable one for decreasing the cut-out risk.

Double lag-screw compression for optimal fixation of intertrochanteric fractures with large fragment gap: A technical note.

Cephalomedullary nailing of unstable intertrochanteric fractures has been established as a fruitful surgical approach with relatively limited complications. Anatomic fracture reduction and proper implant positioning are vital to attaining a favorable long-term surgical outcome. Appropriate intraoperative fracture compression augments stability and invigorates healing. The amount of compression permitted by cephalomedullary nails cannot always adequately reduce large fragment gaps. This paper presents a novel technical trick of double compression of the fracture site, in order to achieve the essential extra compression and reduction when required, thus decreasing the risk of postoperative implant cut-out. The technique was used in 14 out of 277 peritrochanteric fractures treated with cephalomedullary nailing in our trauma center for 12 months, with satisfactory outcomes regarding both fracture site union and postoperative functional capacity.

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.

Blade Augmentation in Nailing Proximal Femur Fractures-An Advantage despite Higher Costs?

BACKGROUND: Proximal femoral fractures occur with increasing incidence, especially in the elderly. Commonly used implants for surgical treatment are cephalomedullary nails. To increase stability, a perforated femoral neck blade can be augmented with cement. The study investigated whether this results in a relevant clinical advantage and justifies the higher cost. MATERIALS AND METHODS: This is a single-center retrospective study of 620 patients with proximal femur fractures treated with cephalomedullary nailing. Between January 2016 and December 2020, 207 male and 413 female patients were surgically treated with a proximal femur nail (DePuy Synthes) using a perforated blade and cement augmentation in cases with severe osteoporosis. Primary outcome measures were the rate of cut-out, tip apex distance and the positioning of the blade in the femoral head. Secondary outcome measures were the implant costs and operating times. RESULTS: Of the 620 femoral neck blades, 299 were augmented with cement. A total of six cut-outs were seen in the first 3 months after the operation. There were three in the cement-augmented group (CAB = cement-augmented blade) and three in the conventional group (NCAB = non-cement-augmented blade). There was a significant positive correlation between age and augmentation, with a mean difference of 11 years between the two groups (CAB 85.7 ± 7.9 vs. NCAB 75.3 ± 15.1; p < 0.05). There was no difference in the tip-apex distance (CAB 15.97 vs. 15.69; p = 0.64) or rate of optimal blade positions between the groups (CAB 81.6% vs. NCAB 83.2%; p = 0.341). Operation times were significantly longer in the cemented group (CAB 62.6 21.2 min vs. NCAB 54.1 7.7 min; p < 0.05), and the implant cost nearly doubled due to augmentation. CONCLUSION: When the principles of anatomic fracture reduction, optimal tip-apex distance and optimal blade position are combined with cement augmentation in cases of severe osteoporosis, a cut-out rate of less than 1% can be achieved. Nevertheless, it should be noted that augmentation remains expensive and prolongs surgery time without definite proof of mechanical superiority.

Clinical and radiological outcome of the Chimaera short nailing system in inter- and subtrochanteric fractures.

BACKGROUND: cephalomedullary devices are popular treatment for femoral intertrochanteric or subtrochanteric fractures. Various complications include post-surgical lateral thigh pain and cut-out. To prevent those complications, a new concept cephalomedullary device system was designed (Chimaera, Orthofix®). This study aimed to evaluate the clinical and radiological outcomes in patients with femoral intertrochanteric or subtrochanteric fractures treated with the proximal femoral cephalomedullary device system. METHODS: A prospective cohort study involved consecutive patients with Arbeitsgemeinschaft für Osteosynthesefragen/ Orthopaedic Trauma Association type 31-A1, 2, 3 fractures treated with the Chimaera short cephalomedullary device system from October 2016 to September 2017 at our level 1 trauma center. The Parker and Palmer mobility score and Jensen social function scores and post-surgical lateral thigh pain were assessed at 3 months post-operatively and compared to before surgery. Radiologic assessment consisted of controlling the position of the cephalic screw by using the tip-apex distance (TAD) and Cleveland zone as well as union and cut-out rates. RESULTS: We included 99 patients (79 women; 100 hips; one bilateral fracture 3 months after a first trochanteric fracture) with a mean follow-up of 2 years. The Parker and Palmer mobility score decreased by 22% at 3 months post-operatively as compared with the pre-fracture score (42/99 patients showed a return to their pre-injury level). The Jensen social function score increased by 16.5% at 3 months post-operatively as compared with the pre-fracture score (68/99 patients showed a return to their pre-injury level). No major intra-operative complication was recorded. Nine TAD scores were > 25 mm. The mean TAD was 16.5 mm (range 5-36), and the lag screw position was well positioned in most (95%) hips according to Cleveland zones. Three patients required revision surgery (one for cut-out of the lag screw, one for hip osteoarthritis and one for gluteus medius insufficiency). All patients but the one with the cut-out showed fracture union. CONCLUSION: The Chimaera short cephalomedullary device exhibited good mid-term functional and radiological outcomes.

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.

Effect of cut-out rescan procedures on the accuracy of an intraoral scanner used for digitizing an ear model: An in vitro study.

PURPOSE: The purpose of this study was to evaluate the impact of the rescanning of mesh holes of different diameters on the accuracy of an intraoral scanner (IOS) used to digitize an ear model. MATERIALS AND METHODS: An ear model was digitized using an intraoral scanner (Medit i500) to obtain a reference mesh. A baseline experimental scan was created by editing a duplicate of the reference mesh using the cut-out tool of the IOS software. Three equal groups were created based on the diameter of the cut-out areas: 2 mm (G1), 5 mm (G2), and 8 mm (G3) (n = 15). The cut-out areas were rescanned and a total of 45 digital files were exported. The discrepancy between the reference and the experimental digital scans was measured using the root mean square calculation (RMS). The data were analyzed by a Kruskal-Wallis test followed by a post hoc Dunn's test with Bonferroni correction. RESULTS: The trueness values ranged from 19.53 to 27.13 µm. There were significant differences in the RMS error values among the groups tested (p < 0.001) and post hoc multiple comparisons showed significant differences between the G1 and G2 groups (p = 0.04), G1 and G3 groups (p < 0.001), and G2 and G3 groups (p = 0.004). Overall, the precision values ranged from 4.93 to 7.73 µm and significant differences in the RMS values were only found between the G1 and G2 groups (p = 0.014). CONCLUSIONS: Mesh hole rescanning affected the scanning accuracy (trueness and precision) of the IOS tested. The larger the diameter of the mesh holes, the less the trueness of the IOS tested. The precision values seemed to be less affected compared with the trueness by the cut-out and rescanning procedures.

Comparison of Helical Blade Systems for Osteoporotic Intertrochanteric Fractures Using Biomechanical Analysis and Clinical Assessments.

Background and Objectives: This study aimed to compare the biomechanical properties and outcomes of osteoporotic intertrochanteric fractures treated with two different helical blade systems, the trochanteric fixation nail-advanced (TFNA) and proximal femoral nail antirotation II (PFNA), to evaluate the efficacy and safety of the newly introduced TFNA system. Materials and Methods: A biomechanical comparison of the two helical blades was performed using uniaxial compression tests on polyurethane foam blocks of different densities. The peak resistance (PR) and accumulated resistance (AR) were measured during the 20 mm advancement through the test block. For clinical comparison, 63 osteoporotic intertrochanteric fractures treated with TFNA were identified and compared with the same number of fractures treated with PFNA using propensity score matching. Ambulatory status, medial migration, lateral sliding, fixation failure, and patient-reported outcomes were compared between the two groups over a minimum of 1 year's follow up. Results: The uniaxial compression test showed that a slightly, but significantly lower resistance was required to advance the TFNA through the test block compared with the PFNA (20 PCF, p = 0.017 and p = 0.026; 30 PCF, p = 0.007 and p = 0.001 for PR and AR, respectively). Clinically, the two groups showed no significant differences in post-operative ambulatory status and patient-reported outcomes. However, in TFNA groups, significantly more medial migration (TFNA, 0.75 mm; PFNA, 0.40 mm; p = 0.0028) and also, lateral sliding was noted (TFNA, 3.99 mm; PFNA, 1.80 mm; p = 0.004). Surgical failure occurred in four and two fractures treated with the TFNA and PFNA, respectively. Conclusions: The results of our study suggest that the newly introduced TFNA provides clinical outcomes comparable with those of the PFNA. However, inferior resistance to medial migration in the TFNA raises concerns regarding potential fixation failures.

Factores asociados al fallo en la osteosíntesis con el uso del sistema de tornillo dinámico de cadera (DHS) en el Hospital Obrero N°1 / Factors associated with failure in osteosynthesis with the use of the dynamic hip screw system (DHS) in the Hospital Obrero N°1

Las fracturas transtrocantericas representan casi la mitad de todas las fracturas de la región proximal del fémur siendo el manejo quirúrgico con el Sistema DHS la indicación más común con un 95% de éxito, con una complicación reportada de 1,9% hasta el 23% de las cuales la más frecuente es el cut out. El objetivo consiste en describir la asociación del fallo de la osteosíntesis con factores predictores evaluados en las radiografías preoperatorias y postoperatorias de los pacientes tratados con el sistema DHS, para determinar la probabilidad de cut out del tornillo dinámico en el Hospital Obrero N°1. Estudio retrospectivo, observacional y prospectivo en el servicio de Ortopedia y traumatología del Hospital Obrero N°1 entre las gestiones 2019 y 2020. Los parámetros radiológicos evaluados fueron la calidad de reducción según la clasificación de Fogagnolo, Índice punta ápex (TAI), Indice punta ápex modificado al calcar (TAICal), índice de Parker, la posición del tornillo en las proyecciones AP y lateral. Se utilizó media, desviación estándar, y rango para variables cuantitativas. Se intervinieron 84 pacientes con diagnóstico de fractura transtrocanterica de fémur mediante el uso del sistema DHS. Se encontró que en el 17,8% de los pacientes la localización del tornillo fue superior ­ anterior, en el 17,8% posterior ­ inferior y la complicación mas frecuente fue la malrotación que representó un 8,3% y en el 82,1% de los pacientes no se presento alguna complicación inmediata. A los 3 meses de seguimiento la complicación mas frecuente fue la varización del angulo cervicodiafisiario representando un 47,6%; el cut out se presentó en el 6% de los pacientes. Se encontró que un 53,6% de los pacientes presentarón una reducción buena y el 7,1% una reducción pobre. El TAI total post operatorio promedio fue de 28,21mm, TAIC al de 18,11mm, índice de Parker de 52,11. Los factores que resultaron estadísticamente significativo como predictores de falla en la osteosintesis para las fracturas transtrocantericas en la población estudiada son la calidad de reducción de la fractura, el índice punta ­ ápex modificado al calcar, índice de Parker y la posición del tornillo en la cabeza femoral, sin embargo estudios previos reportan que el factor que mejor predice la falla en la osteosíntesis es el TAI con una medición mayor de 25 mm, seguido del índice de TADCal y finalmente el índice de Parker.

Transtrochanteric fractures represent almost half of all fractures of the proximal region of the femur, being surgical management with the DHS System the most common indication with 95% success, with a complication reported from 1.9% to 23% of cases. which the most frequent is the cut out.The objective is to describe the association of osteosynthesis failure with predictive factors evaluated in the preoperative and postoperative radiographs of patients treated with the DHS system, to determine the probability of dynamic screw cut-out in Hospital Obrero N°1. Retrospective, observational and prospective study in the Orthopedics and Traumatology service of Hospital Obrero N°1 between 2019 and 2020. The radiological parameters evaluated were the quality of reduction according to the Fogagnolo classification, Tip Apex Index (TAI), Tip Index modified apex to calcar (TAICal), Parker index, screw position in AP and lateral projections. Mean, standard deviation, and range were used for quantitative variables. 84 patients diagnosed with transtrochanteric fracture of the femur were operated on using the DHS system. It was found that in 17.8% of the patients the location of the screw was superior - anterior, in 17.8% posterior - inferior and the most frequent complication was malrotation, which represented 8.3% and in 82, 1% of patients did not present any immediate complication. At 3 months of follow-up, the most frequent complication was varusing of the cervico-diaphyseal angle, representing 47.6%; the cut out occurred in 6% of the patients. It was found that 53.6% of the patients presented a good reduction and 7.1% a poor reduction. The average postoperative total TAI was 28.21mm, TAICal 18.11mm, Parker index 52.11The factors that were statistically significant as predictors of failure in osteosynthesis for transtrochanteric fractures in the population studied are the quality of fracture reduction, the tip-apex index modified to the calcar, the Parker index and the position of the screw in the head. However, previous studies report that the factor that best predicts osteosynthesis failure is TAI with a measurement greater than 25 mm, followed by the TADCal index and finally the Parker

Eccentric distance zone analysis system: New regional evaluation of cephalic fixator tip location for predicting cut-out in geriatric intertrochanteric fractures with internal fixation.

Objective: The aim of this study was to investigate an eccentric distance (ED) zone analysis system for regional evaluation of the cephalic fixator tip based on the ED of the cephalic fixator tip referenced to the radius of its own femoral head to predict cut-out in intertrochanteric fractures (ITF) with internal fixation. Methods: First, we assumed all the femoral heads were regular spheres with the radius (R FD) of "3" for a complete match of the Cleveland zone system and calculated the ED of the cephalic fixator tip by measuring the distances from the cephalic fixator tip to the geometric central axis in the femoral neck and head on both anteroposterior (AP) view and lateral view radiographs. Second, we defined the maximum transverse section of the femoral head into three zones named ED Zone A with ED less than "1," Zone B with ED ranging in "1-2," and Zone C with ED ranging in "2-3" in turns by concentric circles (circles A, B, and C) with the radius of 1/3, 2/3, and 3/3 times of R FD, respectively. Third, we evaluated the ED zones according to the ED and location of the cephalic fixator tip in the eligible 123 ITF patients with single-screw cephalomedullary nail (SCMN) fixation and then analyzed the correlation between the cut-out rate and the ED zones. Results: The cut-out rates in ED Zones A, B, and C were 4.17%, 38.46%, and 100%, respectively. Multivariate logistic regression indicated that ED Zone A had at least a 14 times lower rate of cut-out compared with ED Zone B. The cephalic fixator tip located in ED Zone A has a lower cut-out rate than that in Cleveland Zone 5. The cut-out rate in ED Zone A is significantly lower than that in the region inside Cleveland Zone 5 but outside ED Zone A. Conclusion: ED zone analysis system is a reliable regional evaluation of the cephalic fixator tip position for predicting cut-out in geriatric ITF patients with SCMN fixations and potentially an artificial intelligence measurement during surgery. For decreasing the cut-out rate, the cephalic fixator tip should be located in ED Zone A.

Optimizing fixation methods for stable and unstable intertrochanteric hip fractures treated with sliding hip screw or cephalomedullary nailing: A comparative biomechanical and finite element analysis study.

BACKGROUND: Despite recent advances in implants and surgical techniques, catastrophic and clinical failures in the treatment of intertrochanteric fractures continue to occur, with dire consequences in an overall frail population subset. The aim of the current study is to evaluate the effect of the factors under the surgeons' control, namely fracture reduction and implant selection, on the biomechanical behavior of fracture fixation constructs. MATERIAL-METHODS: An experimental protocol was conducted with the use of instrumented sawbones, in order to validate the finite element models. The implants used were the Gamma3®and DHS systems. Subsequently, a series of scenaria were considered, including various reduction and implant angle combinations. Data were retrieved concerning the peak cancellous bone stresses around the hip screw and the volume of cancellous bone in the femoral head stressed at critical levels, as well as implant stresses and stresses on the cortical bone of the distal fragment. RESULTS: All stable fracture models displayed significantly decreased cancellous bone stresses and implant stresses compared to their unstable counterparts, regardless of implant used. The effect of increasing implant angle led to a decrease in implant stresses in all models studied, but had a beneficial effect on the stresses in the cancellous bone of the proximal fragment only in the subgroups of stable fractures with both implants and unstable fractures treated with a cephalomedullary nail (CMN). In unstable fractures anatomically reduced, the use of CMN led to significantly lower peak stresses in the cancellous bone and a smaller volume of bone stressed at critical levels. Increasing the reduction angle by 5 ° led to a significant decrease in both peak stresses and volume of bone stressed at critical levels, more prominent in the sliding hip screw (SHS) models. Decreasing the reduction angle into varus by 5 or 10 ° led to a significant increase in bone and implant stresses regardless of implant used. CONCLUSIONS: In stable two-part (AO31.A2) fractures the use of the SHS appears to be biomechanically equivalent to CMN. In unstable, anatomically reduced fractures, the use of CMN leads to significantly reduced cancellous bone stresses and decreased rotation of the proximal fragment during loading. A reduction in varus should be avoided at all costs. In unstable fractures treated with SHS a reduction in slight valgus appears to be biomechanically beneficial. The highest implant angle that allows for proper screw position and trajectory in the femoral head should be used for stable fractures with both implants and unstable fractures treated with Gamma3®.