Finite element analysis of fixation stability according to reduction position for internal fixation of intertrochanteric fractures.

In recent years, finite element analysis (FEA) has been instrumental in comparing the biomechanical stability of various implants for femur fracture treatment and in studying the advantages and disadvantages of different surgical techniques. This analysis has proven helpful for enhancing clinical treatment outcomes. Therefore, this study aimed to numerically analyze fixed stability according to location using FEA. In this study, a virtual finite element model was created based on a clinically anatomically reduced patient. It incorporated positive and negative support derived from intramedullary and extramedullary reduction from the anteroposterior (AP) view and neutral support from the lateral view. The generated model was analyzed to understand the biomechanical behavior occurring in each region under applied physiological loads. The simulation results of this study showed that the average von Mises stress (AVMS) of the nail when performing intramedullary reduction for femoral fixation was 187% of the anatomical reduction and 171% of the extramedullary reduction, and individually up to 2.5 times higher. In other words, intramedullary reduction had a very high possibility of fixation failure compared to other reduction methods. This risk is amplified significantly, especially in situations where bone strength is compromised due to factors such as old age or osteoporosis, which substantially affects the stability of fixation. Extramedullary reduction, when appropriately positioned, demonstrates greater stability than anatomical reduction. It exhibits stable fixation even in scenarios with diminished bone strength. In instances in which the bone density was low in the support position, as observed in the lateral view, the AVMS on the nail appeared to be relatively low, particularly in cases of positive support. Additionally, the femur experienced lower equivalent stress only in the extramedullary reduction-negative position. Moreover, by comparing different reduction methods and bone stiffness values using the same femoral shape, this study offers insights into the selection of appropriate reduction methods. These insights could significantly inform decision making regarding surgical strategies for intertrochanteric fractures.

Functional Outcomes of Bipolar Hemiarthroplasty in Unstable Intertrochanteric Femur Fractures in the Elderly: A Prospective Study.

Background Intertrochanteric femur fractures are relatively common injuries among elderly individuals. Treatment options include fixation of intertrochanteric fractures using proximal femoral nails (PFNs), dynamic hip screws (DHSs), and unipolar and bipolar hemiarthroplasty. Unstable types of intertrochanteric fractures (Arbeitsgemeinschaft für Osteosynthesefragen (AO) types 31-A2 and A3) are more common in elderly osteoporotic people. Intertrochanteric femur fractures having a subtrochanteric extension, comminution at the posteromedial cortex, and reverse obliquity are considered to be unstable. The purpose of the study is to evaluate the functional outcomes of an unstable intertrochanteric femur fracture treated with bipolar hemiarthroplasty as the primary treatment option. Aims and objectives This study aims to assess the functional outcomes of bipolar hemiarthroplasty in unstable intertrochanteric fractures in the elderly using the Harris Hip Score (HHS) and the Merle d'Aubigné and Postel Criteria. The time point of assessment was from August 2016 to August 2018. Material and methods Fifteen elderly patients with unstable intertrochanteric fractures of the femur were treated with cemented bipolar hemiarthroplasty. Patients with unstable femur fractures or with osteoporosis and age above 65 years were included in the study. Harris Hip Score and the Merle d'Aubigné and Postel Criteria were used to measure functional outcomes. Patients were followed up at the first, third, and sixth months and subsequently at the end of one year. Results The mean age of the patients was 78.73 years. The majority (11) of the patients were female (73%). The average operative time was 119 minutes, the average blood loss was 380 ml, the mean postoperative hospital stay was 12 days, and the average time taken for mobilization was four days. An average of 15 elderly patients with unstable intertrochanteric fractures of the femur were treated with cemented bipolar hemiarthroplasty. The HHS on the first follow-up was 42.44 (SD of 6.52), followed by a score of 64.43 (SD of 8.11) on the second follow-up, 82.32 (SD of 2.81) on the third follow-up, and 84.23 (SD of 3.15) on the fourth follow-up. Eleven patients had good results, and two had fair results at the one-year follow-up, according to the HHS. According to the Merle d'Aubigné and Postel Criteria, 11 patients had very good results, and two had moderate results at the one-year follow-up. The average Merle d'Aubigné score was 14.6 on the final follow-up after one year. Conclusion Bipolar hemiarthroplasty in an unstable intertrochanteric femur fracture in the elderly results in better functional outcomes, as it helps in early full weight-bearing mobilization, which significantly decreases complications of prolonged immobilization and can be safely considered in the treatment of unstable intertrochanteric fractures in elderly patients.

Comparative efficacy of proximal femoral nail vs dynamic condylar screw in treating unstable intertrochanteric fractures.

BACKGROUND: Among the most frequent hip fractures are trochanteric fractures, which usually occur from low-energy trauma like minor falls, especially in older people with osteoporotic bones. AIM: To evaluate the treatment efficacy of dynamic condylar screws (DCS) and proximal femoral nails (PFN) for unstable intertrochanteric fractures. METHODS: To find pertinent randomized controlled trials and retrospective observational studies comparing PFN with DCS for the management of unstable femoral intertrochanteric fractures, a thorough search was carried out. For research studies published between January 1996 and April 2024, PubMed, EMBASE, Scopus, Web of Science, Cochrane Library, and Google Scholar were all searched. The complete texts of the papers were retrieved, vetted, and independently examined by two investigators. Disputes were settled by consensus, and any disagreements that persisted were arbitrated by a third author. RESULTS: This study included six articles, comprising a total of 173 patients. Compared to the DCS, the PFN had a shorter operation time [mean difference (MD): -41.7 min, 95% confidence interval (95%CI): -63.04 to -20.35, P = 0.0001], higher success rates with closed reduction techniques [risk ratio (RR): 34.05, 95%CI: 11.12-104.31, P < 0.00001], and required less intraoperative blood transfusion (MD: -1.4 units, 95%CI: -1.80 to -1.00, P < 0.00001). Additionally, the PFN showed shorter fracture union time (MD: -6.92 wk, 95%CI: -10.27 to -3.57, P < 0.0001) and a lower incidence of reoperation (RR: 0.37, 95%CI: 0.17-0.82, P = 0.01). However, there was no discernible variation regarding hospital stay, implant-related complications, and infections. CONCLUSION: Compared to DCS, PFN offers shorter operative times, reduces the blood transfusions requirements, achieves higher closed reduction success, enables faster fracture healing, and lowers reoperation incidence.

[Proximal femoral nail antirotation combined with locking plate in the treatment of femoral intertrochanteric fractures with lateral wall fractures].

OBJECTIVE: To investigate the effect of locking plate internal fixation for the treatment of proximal lateral femoral wall fracture. METHODS: From January 2021 to June 2022, 31 patients with intertrochanteric fractures and lateral wall fractures were treated. Among them, 15 patients were treated with proximal femoral nail antirotation (PFNA) fixation including 3 males and 12 females with an average age of (75.87±7.46) years old;the other 16 patients were treated with 3.5 mm pre-curved screw locking plate fixtion for lateral wall fracture including 4 males and 12 females with an average age of (76.15±9.47) years old. After surgery, the surgical index, tip-apical distance(TAD), postoperative standing weight-bearing time, and fracture reduction were compared between two groups. Postoperative hip function was evaluated according to Harris hip score. RESULTS: All patients were followed up for an average of (12±5) months ranging from 7 to 17 months. The immediate postoperative neck angle ranged from 111° to 132°(119.3±8.3)°. Fracture reduction results were excellent in 11 cases, fair in 2, worse in 1 in PFNA group;excellent in 12, fair in 3, worse in 1 in PFNA+locking plate group. One case of the PFNA group had a spiral blade cut out through the femoral head. There were significant differences in the time of operation, the amount of blood loss during the operation, the length of incision between two groups(P<0.05). There was no significant difference in TAD and postoperative standing weight-bearing time between two groups(P>0.05). There were significant differences in Harris scores at 6 months after surgery between two groups(P<0.05). CONCLUSION: The application of PFNA-assisted locking plate in the treatment of femoral intertrochanteric fractures with lateral wall fractures is effective, and can restore the integrity of lateral wall, improve the stability of PFNA internal fixation, and reduce postoperative complications.

Embracing the Timeless Value of Vintage Instrumentation in Orthopedics for Broken Femoral Nail Extraction with Novel Technique.

Introduction: Intramedullary nail placement is a preferred method for femoral shaft fractures due to biomechanical advantages. Despite its simplicity and efficacy, complications, such as pseudoarthrosis and nail fracture, pose challenges. Removing the distal fragment presents a vexing issue, often requiring specialized instruments. Current retrograde techniques may not be universally accessible, potentially leading to non-union site opening and tissue damage. While intramedullary nailing benefits fracture treatment, addressing its removal complications is crucial for further advancements. In this case, universal zig and K-nail reamers are used to extract the broken nail. Case Report: A 42-year-old male suffered an injury to his left thigh in a bike collision. Radiological examination revealed an oblique fracture in the proximal 1/3rd and distal 2/3rd junction of the left femur shaft. Closed reduction and internal fixation were initially performed, but delayed union occurred. Nine months post-surgery, a broken femoral nail and non-united fracture were observed. The patient underwent successful removal and replacement of the broken nail with a wider intramedullary nail. The procedure involved using a universal zig for removal of the proximal fragment and K-nail reamers to remove the distal fragment of the broken nail, and inserting a wider proximal femoral nail. The patient was discharged in satisfactory condition with tolerable weight-bearing. Conclusion: Broken femoral nail presents a unique challenge to the operating surgeon. It requires diligent planning with appropriate instruments and techniques. There have been many techniques devised to tackle this problem and the use of K-nail reamers as described in this case is another innovative method in this regard.

Biomechanical evaluation of ortho-bridge system and proximal femoral nail antirotation in intertrochanteric fractures with lateral wall fracture based on finite element analysis.

Background: The integrity of the lateral wall in femoral intertrochanteric fractures significantly impacts fracture stability and internal fixation. In this study, we compared the outcomes of treating intertrochanteric fractures with lateral wall involvement using the ortho-bridge system (OBS) combined with proximal femoral nail antirotation (PFNA) versus simple PFNA from a biomechanical perspective. Methods: Finite-element models of femoral intertrochanteric fractures with lateral wall involvement were subjected to fixation with OBS combined with PFNA and simple PFNA. Von Mises stress measurements and corresponding displacement assessments for each component of the model, including the proximal femur and lateral wall, were used to evaluate the biomechanical effects of OBS fixation on bone and intramedullary nail stability. Results: Using PFNA alone to fix intertrochanteric fractures with lateral wall involvement resulted in von Mises stress levels on the lateral wall exceeding safe stress tolerances for bone growth. OBS fixation significantly reduced stress on the lateral wall of the femur and minimized the stress on each part of the intramedullary nail, reducing the overall displacement. Conclusion: In cases of intertrochanteric fractures with lateral wall involvement, PFNA fixation alone may compromise the biomechanical integrity of the lateral femoral wall, increasing the risk of postoperative complications. The addition of OBS to PFNA significantly reduces stress on the lateral femoral wall. Consequently, OBS should be considered for lateral wall fixation when managing intertrochanteric fractures combined with lateral wall fractures.

An Unusual Complication Encountered During the Extraction of the Femoral Nail: A Case Report.

Orthopedic implant removal is a common surgery performed either due to patient's complaint of pain, dysfunction or infection or on doctor's advice depending on the nature of the implant and its related future problems. The surgery may range from simple k-wire removal to difficult plate or intramedullary nail removal. Many unforeseen complications are experienced during implant removal, and occasionally, it results in failure of removal, fracture, prolonged per-operative bleeding and damage to nerves and vessels. We report here an unusual complication of coiling of a thick k-wire used during implant extraction surgery to prevent sinking of the nail and the difficulties in removing this coil and the nail, along with the precautions to be taken to avoid such difficulties.

Research Progress on the Treatment of Geriatric Intertrochanteric Femur Fractures with Proximal Femur Bionic Nails (PFBNs).

Intertrochanteric femur fracture is the most common hip fracture in elderly people, and the academic community has reached a consensus that early surgery is imperative. Proximal femoral nail anti-rotation (PFNA) and InterTan are the preferred internal fixation devices for intertrochanteric femur fractures in elderly individuals due to their advantages, such as a short lever arm, minimal stress shielding, and resistance to rotation. However, PFNA is associated with complications such as nail back-out and helical blade cut-out due to stress concentration. As a new internal fixation device for intertrochanteric femur fractures, the proximal femoral biodegradable nail (PFBN) addresses the issue of nail back-out and offers more stable fracture fixation, a shorter lever arm, and stress distribution compared to PFNA and InterTan. Clinical studies have shown that compared to PFNA, PFBNs lead to faster recovery of hip joint function, shorter non-weight-bearing time, and faster fracture healing. This article provides a literature review of the structural characteristics, biomechanical analysis, and clinical studies of PFBNs, aiming to provide a theoretical basis for the selection of internal fixation devices for the treatment of intertrochanteric femur fractures in elderly patients and to improve the quality of life of patients during the postoperative period.

Impact of blade direction on postoperative femoral head varus in PFNA fixed patients: a clinical review and biomechanical research.

Intertrochanteric femur fracture is a common type of osteoporotic fracture in elderly patients, and postoperative femoral head varus following proximal femoral nail anti-rotation (PFNA) fixation is a crucial factor contributing to the deterioration of clinical outcomes. The cross-angle between the implant and bone might influence fixation stability. Although there is a wide range of adjustment in the direction of anti-rotation blades within the femoral neck, the impact of this direct variation on the risk of femoral head varus and its biomechanical mechanisms remain unexplored. In this study, we conducted a retrospective analysis of clinical data from 69 patients with PFNA fixation in our institution. We judge the direction of blade on the femoral neck in on the immediate postoperative lateral X-rays or intraoperative C-arm fluoroscopy, investigating its influence on the early postoperative risk of femoral head varus. p < 0.05 indicates significant results in both correlation and regression analyses. Simultaneously, a three-dimensional finite element model was constructed based on the Syn-Bone standard proximal femur outline, exploring the biomechanical mechanisms of the femoral neck-anti-rotation blade direction variation on the risk of this complication. The results indicated that ventral direction insertion of the anti-rotation blade is an independent risk factor for increased femoral head varus. Complementary biomechanical studies further confirmed that ventral angulation leads to loss of fixation stability and a decrease in fixation failure strength. Therefore, based on this study, it is recommended to avoid ventral directional insertion of the anti-rotation blade in PFNA operation or to adjust it in order to reduce the risk of femoral head varus biomechanically, especially in unstable fractures. This adjustment will help enhance clinical outcomes for patients.

[Comparison of effectiveness of long and short proximal femoral nail anti-rotation in treatment of type A2.3 intertrochanteric fracture of femur].

Objective: To compare the effectiveness of long and short proximal femoral nail anti-rotation (PFNA) in the treatment of type A2.3 intertrochanteric fracture of femur (IFF). Methods: The clinical data of 54 patients with type A2.3 IFF admitted between January 2020 and December 2022 were retrospectively analyzed. According to the length of PFNA nail used in the operation, they were divided into long nail group (PFNA nail length>240 mm, 24 cases) and short nail group (PFNA nail length≤240 mm, 30 cases). There was no significant difference in baseline data such as gender, age, fracture side, body mass index, and time from fracture to operation between the two groups ( P>0.05). The operation time, intraoperative blood loss, intraoperative fluoroscopy frequency, intraoperative reduction quality score, fracture healing, and complications of the two groups were recorded and compared. Harris score was used to evaluate the hip function of patients at 1 year after operation. According to the relationship between the fracture line of type A2.3 IFF and the lesser trochanter, the two groups of patients were divided into type Ⅰ(the fracture line extends to the level of the lesser trochanter), type Ⅱ(the fracture line extends to less than 2 cm below the lesser trochanter), and type Ⅲ (the fracture line extends to more than 2 cm below the lesser trochanter), and the postoperative stability and internal fixator loosening of each subtype were evaluated. Results: The operation time, intraoperative blood loss, and intraoperative fluoroscopy frequency in short nail group were significantly less than those in long nail group ( P<0.05). There was no significant difference in the intraoperative reduction quality score between the two groups ( P>0.05). Patients in both groups were followed up 12-18 months, with an average of 13.5 months. The postoperative stability score of short nail group was significantly lower than that of long nail group ( P<0.05). The Harris score in the long nail group was significantly higher than that in the short nail group at 1 year after operation ( P<0.05), but there was no significant difference in Harris score grading between the two groups ( P>0.05). Complications occurred in 3 cases of the long nail group (including 1 case of coxa varus caused by external nail entry point and 2 cases of loose internal fixator), and 7 cases of the short nail group (including 1 case of coxa varus caused by external nail entry point and 6 cases of loose internal fixator). Neither group had any anterior femoral arch damage, there was no significant difference in the incidence of complications between the two groups ( P>0.05). The number of type Ⅲ patients was relatively small and not included in the statistics; there was no significant difference in the postoperative stability score and the incidence of internal fixator loosening between the long and short nail groups in type Ⅰ patients ( P>0.05). In type Ⅱ patients, the postoperative stability score and the incidence of internal fixation loosening in the long nail group were significantly better than those in the short nail group ( P<0.05). Conclusion: Long PFNA fixation for type A2.3 IFF has longer operation time and more intraoperative blood loss, but the overall stability of fracture is better after operation. For type A2.3 IFF with fracture line extending to less than 2 cm below the lesser trochanter, long PFNA is used for fixation, although the surgical trauma is large, but the postoperative stability is better than that of short PFNA; for type A2.3 IFF with fracture line extending to the lesser trochanter, there is no significant difference in postoperative stability between long and short PFNAs.

A Comparison of the Clinicoradiological Outcomes of Intertrochanteric Fractures Treated Using Proximal Femoral Nail and Proximal Femoral Nail Anti-rotation.

Background Managing intertrochanteric fractures presents challenges for orthopedic surgeons, not only in fixing the fracture but also in preventing and managing associated complications, especially in the vulnerable geriatric population. Cephalomedullary nails are commonly used for surgical fixation due to their favorable functional profile, which preserves the hip's abductor lever arm and proximal femur anatomy. However, there's a lack of data comparing two major options: proximal femoral nail (PFN) and proximal femoral nail anti-rotation (PFNA). This study aimed to compare the radiological fracture reduction and fixation as well as functional outcomes of these two implants in treating intertrochanteric fractures. Methods The study, spanning 24 months, involved a prospective comparative design. Participants included patients diagnosed with intertrochanteric femur fractures classified as AO Type 31 A1, AO Type 31 A2, and AO Type 31 A3. Fifty patients were evenly distributed into PFN and PFNA groups. Preoperatively, clinical and radiological assessments were conducted, along with serum vitamin D level measurements. Surgeries, performed under anesthesia with image intensifier guidance, followed defined reduction and implant insertion protocols for each group. Postoperatively, evaluations were conducted up to six months, examining parameters such as tip-apex distance (TAD), Cleveland index, and modified Harris hip score, while documenting intraoperative duration and blood loss. Data analysis utilized the statistical software Statistical Package for Social Sciences (SPSS), version 22.0 (IBM Corp., Armonk, NY), employing descriptive statistics, chi-square tests, independent t-tests, and paired t-tests, with significance set at p < 0.05. Results In our study, 50 patients were enrolled, with equal gender distribution (64.0% male, 36.0% female, p=1.000). The mean ages in the PFN and PFNA groups were 66.2 ± 9.8 years and 66.4 ± 11.3 years, respectively (p=0.936). All fractures united by six months, with no implant-related complications reported. PFNA showed significantly lower blood loss and shorter surgery durations (p<0.001). TAD and neck shaft angle were similar between groups (p=0.826, p=0.555). Cleveland index placement and modified Harris hip score improvement were comparable (p=0.836, p<0.001). Predominant vitamin D deficiency was observed in both groups. Conclusion PFNA offers measurable intraoperative benefits over conventional PFN in terms of operative time, blood loss, and need for fluoroscopic imaging. However, no statistically observable benefits were noted in postoperative functional outcomes or complications between the two implants.

Is nail-plate docking worth the effort? A biomechanical analysis of docking a plate and a nail in peri-implant femur fractures.

Purpose: The ideal treatment of peri-implant femur fractures (PIFFs) remains unclear due to the thin clinical and biomechanical evidence concerning the most suitable form of osteosynthesis. The purpose of the present study was thus to determine the biomechanical stability that results from combining a cephalomedullary nail and a plate for proximal PIFFs, especially when the nail-plate docking technique is applied. Methods: Twenty four PIFFs were simulated in both 12 foam and 12 composite specimens and were stabilized via a combination of a cephalomedullary nail and a plate. The control group (n = 6) had a nail and a plate without a connection, while the intervention group (n = 6) had a screw that connected the plate with the interlocking screw hole of the nail, thereby creating a nail-plate docking system. The specimens were evaluated under axial and torsional loading using a material-testing machine and a 3D metrology system. Results: The data regarding stiffness, failure load, and failure displacement showed significantly higher stability for specimens without nail-plate docking. For docked specimens, a non-significant trend toward a higher resistance to torque was observed. Both techniques displayed no significant difference in fracture gap displacement or total displacement. Conclusion: The present study suggests that nail-plate docking of a cephalomedullary nail, and a plate significantly decreases the stiffness and stability of osteosynthesis under axial loading. However, there seems to be a tendency toward higher resistance to torque. Therefore, surgeons should consider this technique if higher torsional stability is necessary, and they should decide against it, if axial stability is preferred.

Changes in nail position and antirotation blade angles on the risk of femoral head varus in PFNA fixed patients: a clinical review and comprehensive biomechanical research.

BACKGROUND: Femoral head varus triggers poor clinical prognosis in intertrochanteric fracture patients with proximal femoral nail antirotation (PFNA) fixation. Studies present that changes in nail position and screw insertion angles will affect fixation stability, but the biomechanical significance of these factors on the risk of femoral head varus has yet to be identified in PFNA fixed patients. METHODS: Clinical data in PFNA fixed intertrochanteric fracture patients have been reviewed, the relative position of intermedullary nail has been judged in the instant postoperative lateral radiography. Regression analyses have been performed to identify the effect of this factor on femoral head varus. Corresponding biomechanical mechanism has been identified by numerical mechanical simulations. RESULTS: A clinical review revealed that ventral side nail insertion can trigger higher risk of femoral head varus, corresponding numerical mechanical simulations also recorded poor fixation stability in models with ventral side nail insertion, and changes in the trajectory of anti-rotation blade will not obviously affect this tendency. CONCLUSIONS: Ventral side insertion of intramedullary nail can trigger higher risk of femoral head varus in PFNA fixed patients by deteriorating the instant postoperative biomechanical environment, and changes in blade trajectory cannot change this tendency biomechanically. Therefore, this nail position should be adjusted to optimize patients' prognosis.

Tibio-Talo-Calcaneal Arthrodesis: Evaluation of the Effectiveness of a Specific Surgical Technique in 17 Cases.

INTRODUCTION: Ankle arthrodesis is a crucial surgical intervention for advanced hindfoot conditions, aiming to restore plantigrade walking and alleviate pain. This study evaluates the effectiveness of a specific surgical approach for tibiotalocalcaneal arthrodesis (TTCA), focusing on rigorous risk factor control, corticocancellous grafting, and internal fixation using an angled retrograde femoral nail in the sagittal plane, and assesses the outcomes of this approach in terms of bone fusion and reduction of postoperative complications. MATERIALS AND METHODS: This retrospective analysis includes 17 patients who underwent TTCA in a trauma-orthopedic department over seven years. Data were collected from medical records, the HOSIX software, and patient consultations. Preoperative assessments, surgical techniques, postoperative care, and follow-up evaluations were documented. RESULTS: The mean age of patients was 42.4 years, with a male predominance. Surgical indications included post-traumatic arthropathy (53%), inflammatory arthropathy, ankle infectious pathologies, and Charcot foot and ankle prosthesis failures. All patients underwent standard preoperative evaluations and received corticocancellous grafts. An angled retrograde femoral nail in the sagittal plane was used for internal fixation. Postoperative immobilization lasted 6 to 8 weeks, with subsequent rehabilitation. The bone fusion rate was 100%, with a low complication rate (23.5%). DISCUSSION: Our study showed a younger patient population with a male predominance, different from some previous studies. Surgical techniques, including the anterior approach combined with a lateral subtalar approach, were consistent with some studies but differed from others. Corticocancellous grafts and the angled retrograde femoral nail in the sagittal plane demonstrated favorable outcomes in terms of fusion. Complication rates were lower compared to some previous reports, highlighting potential improvements in postoperative management. CONCLUSION: The surgical approach described for TTCA, emphasizing rigorous risk factor control, corticocancellous grafting, and internal fixation using an angled retrograde femoral nail in the sagittal plane, led to satisfactory bone fusion and reduced postoperative complications. These results underscore the importance of this approach in achieving optimal functional outcomes in ankle arthrodesis.

Feasibility biomechanical study of injectable Biphasic Calcium Phosphate bone cement augmentation of the proximal femoral nail antirotation (PFNA) for the treatment of two intertrochanteric fractures using cadaveric femur.

This study evaluated the feasibility of the femoral bone after fixation using biphasic calcium phosphate cement-augmentation of the proximal femoral nail antirotation (PFNA) compared with PFNA without cement. This study presented to compare the stiffness, fatigue testing, and compressive strength between stable (AO31-A2.1) and unstable (AO31-A3.3) intertrochanteric fractures treated by cement augmented PFNA of the cadaveric femoral. Biphasic calcium phosphate cement was injected to align and compatible with PFNA and the reconstructive procedure was monitored the cement placement using x-ray imaging during operation. The testing demonstrated that the cement could be injected through a small needle (13 G, 16 cm length, 1.8 mm inner diameter) within a suitable operating time. The feasibility study of the biomechanical testing was divided into three tests: stiffness test, fatigue cyclic load, and compression test. The results showed that the cement-augmented specimens exhibited higher stiffness than the control specimens without cement. The cement-augmented specimens also showed lower strain energy during the fatigue test, resulting in higher compressive strength (4730.7 N) compared to the control specimens (3857.4 N). There is a correlation between BMD and fracture load and the increase in compression load of the cement-augmented femoral compared to the controls as well as an increase in strain energy of fatigue cyclic testing was found. Biphasic calcium phosphate cement-augmented of the PFNA biomechanically enhanced the cut-out resistance in intertrochanteric fracture. This procedure is especially efficient for unstable intertrochanteric fracture suggesting the potential benefits of using biphasic calcium phosphate cement in medical applications.

Rates of interlock screw back-out are high with the retrograde femoral nailing advanced system for distal femur fractures.

PURPOSE: The retrograde femoral nailing advanced (RFNA) system (DePuy synthes) is a commonly used implant for the fixation of low distal femur and periprosthetic fractures. There is concern that the rate of distal interlock screw back-out may be higher for the RFNA compared to other nails (ON). The purpose of this study was to evaluate the incidence of interlock screw back-out and associated screw removal for RFNA versus ON, along with associated risk factors. METHODS: A retrospective comparative study of patients who underwent retrograde nailing for a distal femur fracture at an academic level one trauma center was performed. The incidence of distal interlock screw back-out and need for screw removal were compared for RFNA versus a propensity score matched cohort who received other nails. RESULTS: One hundred and ten patients underwent retrograde nailing with the RFNA for a distal femur fracture from 2015 to 2022 (average age: 66, BMI: 32, 52.7% smokers, 54.5% female, 61.8%). There was a significantly higher rate of interlock back-out in the RFNA group compared to the ON (27 patients, 24.5% vs 12 patients, 10.9%, p = 0.01), which occurred 6.3 weeks postoperatively. Screw removal rates for back-out were not significantly different for the RFNA group versus ON (8 patients, 7.3% vs 3 patients, 2.7%, p = 0.12). CONCLUSION: In this retrospective comparative study of distal femur fractures treated with retrograde nailing, the RFNA implant was associated with an increased risk of distal interlock screw back-out compared to other nails.

Finite element study on the micromechanics of cement-augmented proximal femoral nail anti-rotation (PFNA) for intertrochanteric fracture treatment.

Blade cut-out is a common complication when using proximal femoral nail anti-rotation (PFNA) for the treatment of intertrochanteric fractures. Although cement augmentation has been introduced to overcome the cut-out effect, the micromechanics of this approach remain to be clarified. While previous studies have developed finite element (FE) models based on lab-prepared or cadaveric samples to study the cement-trabeculae interface, their demanding nature and inherent disadvantages limit their application. The aim of this study was to develop a novel 'one-step forming' method for creating a cement-trabeculae interface FE model to investigate its micromechanics in relation to PFNA with cement augmentation. A human femoral head was scanned using micro-computed tomography, and four volume of interest (VOI) trabeculae were segmented. The VOI trabeculae were enclosed within a box to represent the encapsulated region of bone cement using ANSYS software. Tetrahedral meshing was performed with Hypermesh software based on Boolean operation. Finally, four cement-trabeculae interface FE models comprising four interdigitated depths and five FE models comprising different volume fraction were established after element removal. The effects of friction contact, frictionless contact, and bond contact properties between the bone and cement were identified. The maximum micromotion and stress in the interdigitated and loading bones were quantified and compared between the pre- and post-augmentation situations. The differences in micromotion and stress with the three contact methods were minimal. Micromotion and stress decreased as the interdigitation depth increased. Stress in the proximal interdigitated bone showed a correlation with the bone volume fraction (R2 = 0.70); both micromotion (R2 = 0.61) and stress (R2 = 0.93) at the most proximal loading region exhibited a similar correlation tendency. When comparing the post- and pre-augmentation situations, micromotion reduction in the interdigitated bone was more effective than stress reduction, particularly near the cement border. The cementation resulted in a significant reduction in micromotion within the loading bone, while the decrease in stress was minimal. Noticeable gradients of displacement and stress reduction can be observed in models with lower bone volume fraction (BV/TV). In summary, cement augmentation is more effective at reducing micromotion rather than stress. Furthermore, the reinforcing impact of bone cement is particularly prominent in cases with a low BV/TV. The utilization of bone cement may contribute to the stabilization of trabecular bone and PFNA primarily by constraining micromotion and partially shielding stress.

Retrospective evaluation of radiological and clinical outcomes after surgical treatment of proximal femoral fractures utilizing PFNA and PFNA augmented.

INTRODUCTION: The primary aim of this study was to evaluate the clinical and radiological outcomes after surgical treatment of proximal femoral fractures utilizing the Proximal Femoral Nail Antirotation (PFNA), with the main focus on complications and reoperations. The secondary aim was to compare the outcomes of patients with and without cement augmentation of the cephalomedullary nails. MATERIALS AND METHODS: All patients with an acute proximal femoral fracture consequently treated with a PFNA between January 2011 and Dezember  2018 were evaluated. Clinical and radiological data were assessed for intra- and postoperative complications, including treatment failure. In addition, intra- and postoperative radiographs were used to determine the position of the implant, and any migration, via Tip-Apex-Distance (TAD) and the caput-collum-diaphyseal angle (CCD). The accuracy of the fracture reduction was rated according to Baumgaertners criteria. RESULTS: Two hundred sixty-four consecutive patients (mean age 78.8 ± 12.0; 73.1% female) were included. The predominant OTA/AO fracture classification was 31A1 (153 cases, 58.0%). The average duration of surgery was 63.1 ± 28.0 min and showed no significant differences between PFNA and PFNA with augmentation. The implant positioning was rated as good in 222 cases (84.1%). Two hundred sixty-three patients (99.6%) showed evidence of healing within the time frame of three months postoperatively, one case of delayed union healed after secondary dynamization. During the observational period, 18 patients (6.8%) required a total of 23 additional surgeries. Overall, a lower reoperation rate was observed following the use of the augmentation option (2/86 patients (2.3%) vs. 16/178 patients (9.0%), p = 0.04). In particular, there were no cases of cut-out or cut-through among patients who underwent augmentation as part of osteosynthesis. CONCLUSIONS: Overall reoperation rate after surgical treatment of proximal femoral fractures utilizing the Proximal Femoral Nail Antirotation (PFNA) was 6.8%, with 23 additional surgeries performed in 18 patients. The usage of the PFNA with augmentation showed equally good implant positioning, excellent healing rates and fewer postoperative complications compared to the PFNA implant alone with a similar overall duration of surgery.

The clinical efficacy of Medial Sustain Nail(MSN) and Proximal femoral nail anti-rotation(PFNA) for fixation of medial comminuted trochanteric fractures: a prospective randomized controlled trial.

PURPOS: To evaluate the clinical efficacy of the Medial Sustain Nail (MSN) for medial comminuted trochanteric fractures fixation in comparison to Proximal Femoral Nail Antirotation (PFNA) through a clinical study. METHODS: A non-inferiority randomized controlled trial was conducted at a single centre between July 2019 and July 2020. Fifty patients diagnosed comminuted trochanteric fractures were randomly assigned to either the MSN group (n = 25) or the PFNA group (n = 25). A total of forty-three patients were included in the final study analysis. The primary outcome measure was Short Form 36 health surgery physical component summary (SF-36 PCS) score. Secondary outcomes included the Oxford Hip Scores (OHS), weight bearing, complication relate to implant and so on. This study was not blined to surgeons, but to patients and data analysts. RESULTS: The MSN demonstrated significantly better functional outcomes as measured by SF-36 PCS and OHS at six months postoperative compared to PFNA (p < 0.05). Union of fractures in the MSN group reached 90.9% at three months after surgery, whereas the PFNA group achieved a union rate of 57.1% (p < 0.05). Furthermore, weight-bearing time of MSN group was earlier than PFNA group (p < 0.05). Additionally, complications related to implant usage were more prevalent in the PFNA group (33.3%) compared to the MSN group (4.5%) (p < 0.05). CONCLUSION: MSN exhibited superior quality of life outcomes compared to PFNA at six months postoperative. This indicates that MSN effectively reconstructs medial femoral support in patients with comminuted trochanteric fractures, which facilitates early weight-bearing and accelerates the recovery process. TRIAL REGISTRATION: Trial registration number: NCT01437176, Date of the trial registration:2011-9-1, Date of commencement of the study:2011-9, Date of enrolment/recruitment of the study subjects:2019-7.

Outcomes of Distal Third Femur Fractures in Patients 18 Years and Older: A Pilot Study.

INTRODUCTION: The selection of the most optimal fixation method for fractures of the distal femur, whether intramedullary nail (NL), lateral locking plate (PL), or nail/plate (NP) is not always clear. This study retrospectively evaluates surgical patients with distal femur fractures and introduces a pilot study using cluster analysis to identify the most optimal fracture fixation method for a given fracture type. METHODS: This is a retrospective cohort study of patients 18 years and older with an isolated distal femur fracture who presented to our Level-1 trauma center between January 1, 2012, and December 31, 2022, and obtained NL, PL, or NP implants. Patients with polytrauma and those without at least six months of follow-up were excluded. A chart review was used to obtain demographics, fracture classification, fixation method, and postoperative complications. A cluster analysis was performed. The following factors were used to determine a successful outcome: ambulatory status pre-injury and 6-12 months postoperatively, infection, non-union, mortality, and implant failure. RESULTS: A total of 169 patients met inclusion criteria. No statistically significant association between the fracture classification and fixation type with overall outcome was found. However, patients treated with an NP (n = 14) had a success rate of 92.9% vs only a 68.1% success rate in those treated with a PL (n = 116) (p = 0.106). The most notable findings in the cluster analysis (15 total clusters) included transverse extraarticular fractures demonstrating 100% success if treated with NP (n = 6), 50% success with NL (n=2), and 78.57% success with PL fixation (n=14). NP constructs in complete articular fractures demonstrated success in 100% of patients (n = 5), whereas 77.78% of patients treated with NL (n = 9) and 61.36% of those treated with PL (n = 44). CONCLUSIONS: Plate fixation was the predominant fixation method used for distal third femur fractures regardless of fracture classification. However, NP constructs trended towards improved success rates, especially in complete intraarticular and transverse extraarticular fractures, suggesting the potential benefit of additional fixation with these fractures. Cluster analysis provided a heuristic way of creating patient profiles in patients with distal third femur fractures. However, a larger cohort study is needed to corroborate these findings to ultimately develop a clinical decision-making tool that also accounts for patient specific characteristics.