Lateral Femoral Wall Research Articles

Lateral femoral wall thickness in trochanteric hip fractures: a systematic review.

Thin lateral femoral wall has been investigated as a sign of instability in trochanteric hip fractures, necessitating lateral wall reconstruction or the use of a cephalomedullary nail (CMN). Various cut-off values have been proposed to guide implant choice. This review aims to determine the clinical significance of the lateral femoral wall thickness (LWT) in trochanteric hip fractures and identify an optimal cut-off value for increased risk of lateral wall (LW) fracture when using Dynamic Hip Screw (DHS). A comprehensive search was conducted in databases including Medline, Embase, and the Cochrane library up to July 2023. A predefined strategy was employed, with 5 eligible studies critically appraised using the methodological index for non-randomized studies (MINORS) criteria. Outcomes assessed encompassed the standardised mean difference (SMD) of LWT between the LW fracture and non LW fracture groups, aggregate LWT mean in LW fracture group, and the relation between AO/OTA fracture type with LW fracture utilising the chi-square test. Among 481 patients from 5 studies, 112 experienced LW fractures, while 369 did not postoperatively. Analysis indicated a significantly lower LWT in the LW fracture group (SMD -1.13, I² = 41.3%, p = 0.146). The mean LWT in the LW fracture group was 18.2 mm, with a 95% confidence interval of 17.29-19.10 mm. A preoperative thin lateral femoral wall is a critical predictor of fixation failure and suboptimal functional outcomes when using a DHS. Thorough evaluation of pre- and intraoperative x-rays is essential. CMN is recommended over DHS in cases with LWT measurements <19 mm.

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

To investigate the effect of locking plate internal fixation for the treatment of proximal lateral femoral wall fracture. 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. 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). 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.

Biomechanical comparison of an intramedullary nail combined with a reconstruction plate combination versus a single intramedullary nail in unstable intertrochanteric fractures with lateral femoral wall fracture: A finite element analysis.

This study aimed to compare the biomechanical performance of an intramedullary nail combined with a reconstruction plate and a single intramedullary nail in the treatment of unstable intertrochanteric femoral fractures with a fracture of the lateral femoral wall (LFW). A three-dimensional finite element (FE) femur model was established from computed tomography images of a healthy male volunteer. A major reverse obliquity fracture line, associated with a lesser trochanteric fragment defect and a free bone fragment of the LFW, was developed to create an AO/OTA type 31-A3.3 unstable intertrochanteric fracture mode. Two fixation styles were simulated: a long InterTAN nail (ITN) with or without a reconstruction plate (RP). A vertical load of 2100 N was applied to the femoral head to simulate normal walking. The construct stiffness, von Mises stress, and model displacement were assessed. The ITN with RP fixation (ITN/RP) provided higher axial stiffness (804 N/mm) than the ITN construct (621 N/mm). The construct stiffness of ITN/RP fixation was 29% higher than that of ITN fixation. The peak von Mises stress of the implants in the ITN/RP and ITN models was 994.46 MPa and 1235.24 MPa, respectively. The peak stress of the implants in the ITN/RP model decreased by 24% compared to that of the ITN model. The peak von Mises stress of the femur in the ITN/RP model was 269.06 MPa, which was lower than that of the ITN model (331.37 MPa). The peak stress of the femur in the ITN/RP model was 23% lower than that of the ITN model. The maximum displacements of the ITN/RP and ITN models were 12.12 mm and 13.53 mm, respectively. The maximum displacement of the ITN/RP model decreased by 12% compared with that of the ITN model. The study suggested that an additional plate fixation could increase the construct stiffness, reduce the stresses in the implant and femur, and decrease displacement after intramedullary nailing. Therefore, the intramedullary nail and reconstruction plate combination may provide biomechanical advantages over the single intramedullary nail in unstable intertrochanteric fractures with a fractured LFW.

The effect of distal locking mode on postoperative mechanical complications in intertrochanteric fractures: a retrospective cohort study of five hundred andseven patients.

The optimal choice of distal locking modes remains a subject due to limited available data, and therefore, this study aims to investigate the relationship between distal locking mode and postoperative mechanical complications in an intertrochanteric fracture (ITF) population who underwent closed reduction and intramedullary fixation with a PFNA-II. Patients aged 65years or older who underwent surgery with PFNA-II fixation in a university teaching hospital between January 2020 and December 2021 were potentially eligible. Based on the distal locking mode, patients were classified into static, dynamic, and limited dynamic groups, among which the differences were tested using univariate analysis. Multivariate logistic regression was used to examine whether the distal locking mode was independently associated with the risk of postoperative oneyear mechanical complications, adjusting for covariates and potential confounders. Subgroup analyses were performed to evaluate the robustness of the findings. Among 507 eligible patients, 33 (6.5%) developed postoperative mechanical complications. In the univariate analysis, sex (P = 0.007), fracture type (P = 0.020), LAT Parker ratio (P = 0.023), and lateral femoral (P = 0.003) wall showed that the differences were significant. Compared to the static group, the limited dynamic group and the dynamic group showed higher odds of postoperative mechanical complications (OR = 3.314, 95% CI: 1.215-9.041; and OR = 3.652, 95% CI: 1.451-9.191, respectively). These associations were robust across a series of analyses, including adjusting for confounders and subgroup analyses. Using a distal non-static locking mode significantly increases the risk of postoperative mechanical complications, and static locking could be a preferable option when treating an intertrochanteric fracture.

Laterally Protruded Cephalomedullary Nail Lag Screws are a Source of Consistent Thigh Pain After Pertrochanteric Fracture.

To assess the correlation between the amount of proximal screw lateralization and clinical symptoms in patients treated with a cephalomedullary nail (CMN) after a pertrochanteric fracture. Retrospective study. Level 1 trauma center. Patients operated for a pertrochanteric fracture (OTA/AO A1, A2, A3) between 2019 and 2022 and treated with a CMN were included. Three measurements were evaluated: D1 distance between the most laterally prominent point of the lag screw and the line tangent to the greater trochanter, D2 distance between the lateral femoral cortex and the most laterally prominent point of the lag screw, and D3 distance between the point where the lag screw emerges at the lateral edge of the femur shaft and the skin's surface. Clinical scores and information regarding lateral thigh pain were obtained, and a correlation analysis was performed. Mean age of the study cohort (n = 134) was 77.9 ± 12.3 years. Patients with categorical protrusion (considered present in cases where the distance between the lateral tip of the lag screw and the lateral border of the greater trochanter was ≥0.2 mm) had significantly higher rates of lateral thigh pain ( P = 0.007) and discomfort while lying on the side ( P = 0.032) compared with those without protrusion. Correlation analyses showed a positive correlation between measurements D1 and D2 and lateral thigh pain (r = 0.324 and r = 0.334, respectively, P < 0.001) and a negative correlation between D3 and lateral thigh pain (r = -0.286, P = 0.001). Regression analysis showed that higher D1 and D2 distances and shorter D3 distances are risk factors for lateral thigh pain ( P = 0.001, 0.001, and 0.002, respectively). Increasing lateral protrusion of the lag screw leads to significantly greater clinical complaints and lateral hip pain in patients treated with a CMN. Patients with lower distance between the lateral femoral wall and the skin are at higher risk of lateral pain. Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Lateral wall thickness is not associated with revision risk of medially stable intertrochanteric fractures fixed with a sliding hip screw.

This study aimed to determine whether lateral femoral wall thickness (LWT) < 20.5 mm was associated with increased revision risk of intertrochanteric fracture (ITF) of the hip following sliding hip screw (SHS) fixation when the medial calcar was intact. Additionally, the study assessed the association between LWT and patient mortality. This retrospective study included ITF patients aged 50 years and over treated with SHS fixation between 2019 and 2021 at a major trauma centre. Demographic information, fracture type, delirium status, American Society of Anesthesiologists grade, and length of stay were collected. LWT and tip apex distance were measured. Revision surgery and mortality were recorded at a mean follow-up of 19.5 months (1.6 to 48). Cox regression was performed to evaluate independent risk factors associated with revision surgery and mortality. The cohort consisted of 890 patients with a mean age of 82 years (SD 10.2). Mean LWT was 27.0 mm (SD 8.6), and there were 213 patients (23.9%) with LWT < 20.5 mm. Overall, 20 patients (2.2%) underwent a revision surgery following SHS fixation. Adjusting for covariates, LWT < 20.5 mm was not independently associated with an increased revision or mortality risk. However, factors that were significantly more prevalent in LWT < 20.5 mm group, which included residence in care home (hazard ratio (HR) 1.84; p < 0.001) or hospital (HR 1.65; p = 0.005), and delirium (HR 1.32; p = 0.026), were independently associated with an increased mortality risk. The only independent factor associated with increased risk of revision was older age (HR 1.07; p = 0.030). LWT was not associated with risk of revision surgery in patients with an ITF fixed with a SHS when the calcar was intact, after adjusting for the independent effect of age. Although LWT < 20.5 mm was not an independent risk factor for mortality, patients with LWT < 20.5 mm were more likely to be from care home or hospital and have delirium on admission, which were associated with a higher mortality rate.

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

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. 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. 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. 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.

Functional outcome of intertrochanteric fractures treated with trochanteric stabilizing plates

Background: Intertrochanteric fractures account for significant percentage of health care costs and result in high rates of morbidity and mortality. Since higher rate of mortality and complications most fractures can be successfully treated with trochanteric stabilizing plates. This study was conducted to assess functional outcome in intertrochanteric fracture femur treated with trochanteric stabilizing plates and define ideal mode of fixation for such fractures. Trochanter stabilizing plate (TSP) is modular extension of dynamic hip screw (DHS) that is mounted on lateral femoral wall to stabilize greater trochanter. It provides the flexibility to achieve plate to bone apposition as well as axial compression or angular stability because of three screw fixations at the proximal fragment. TSF can provide a stress shield for the lateral trochanteric wall and prevent lateral migration of proximal fragments. Thus, TSF does not fail at the screw bone interface and provide a strong anchor in osteoporotic bone. The multiple locking screw holes of the TSF provide various options to tackle complex fracture pattern. It functions as an internalized external fixator and minimizes the pressure on the periosteum and encourages biological healing. Methods: A total of 30 subjects of intertrochanteric fractures undergoing treatment with trochanteric stabilizing plates were taken up for the study after informed consent. Results: Significant results were obtained using Harris hip score (HHS) at different postoperative follow up time intervals with good outcome and low complication rate. Conclusions: Trochanteric buttress plate creates biomechanically stable construct by incorporating the comminuted trochanter it restores the proximal femoral anatomy, ensuring anatomical reduction hence subsequently reduces limb length discrepancy. We thus conclude this is an effective technique and has excellent functional and radiological outcomes with minimal complication and early rehabilitation rates. As Intertrochanteric fractures of the hip is a very common condition affecting a large number of patients of variable demographics and racial background, a more widespread study is required for a more conclusive study.

Prediction of internal fixation failure of femoral trochanteric fracture by external wall morphology

To investigate the relationship between the shape of the lateral wall and the early failure of internal fixation in the fracture of the femoral trochanteric region(FFT). Total 295 patients with femoral trochanteric fracture underwent internal fixation from January 2015 to January 2020 were selected. The patients were divided into two groups according to whether there was early internal fixation failure after surgery, 19 patients in the failure group and 276 patients in the normal group. Gender, affected side, age, AO classification, body mass index(BMI), preoperative hemoglobin, X-ray measurement of lower lateral wall thickness, preoperative internal diseases, intraoperative blood loss, postoperative tip apex distance(TAD), postoperative neck shaft angle, operation time and other data were compared between two groups. The shape of the lateral wall was compared between two groups, and the correlation between the shape of the lateral wall and the early internal fixation failure of femoral trochanteric fracture was analyzed. All patients were followed up for more than 1 year. There was no significant difference between two groups in terms of intraoperative blood loss, operation time, postoperative TAD, and postoperative neck shaft angle(P>0.05). At the latest follow-up, the visual anaglue scale (VAS) of the failure group was higher than that of the normal group(P<0.01), and the Harris score of the failure group was lower than that of normal group(P<0.05). The receiver operator characteristic (ROC) curve between shape of lateral wall and failure of early internal fixation of femoral trochanteric fracture was drawn. The critical value of the midpoint lateral wall thickness was 16.5 mm, and the area under the ROC curve was 0.845;The critical value of average sidewall thickness was 16.5 mm, and the area under ROC curve was 0.838;The critical value of the axial area of the sidewall was 7.5 mm, and the area under the ROC curve was 0.826. The shape of the lateral femoral wall measured by CT could be used as a predictive factor for the early failure of internal fixation of femoral trochanteric fractures. For patients at risk, more reasonable surgical plans and postoperative preventive measures should be developed.

Advances in the Restoration and Fixation of Lateral Femoral Wall Fracture

Hip fractures, especially intertrochanteric fractures, are more common with aging. After decades of progress, it is a general consensus to carry out internal fixation for this group of patients. However, the recent focus is on unstable intertrochanteric fractures to ensure better prognosis and prevent internal fixation failure. The lateral femoral wall, as a novel concept, is often disregarded. Many scholars have recognized that the lateral wall of the proximal femoral plays a crucial role in the stability of internal fixation for intertrochanteric fractures. In this paper, the historical evolution, definition, clinical significance, injury classification, choice of internal fixation, and possible prognosis of lateral femoral wall fracture are reviewed in order to provide clinicians strong evidence of treatment strategies.

Are The Lateral Wall Reduction And Ideal Tip-Apex Distance Important In Reverse Oblique And Transverse Intertrochanteric Femoral Fractures (31-A3) Treated With Gamma Nail?

Purpose: Reverse oblique and transverse intertrochanteric femoral fractures (31A3 AO/OTA classification) have their own mechanical and anatomical properties. The aim of our study is to verify whether the reduction of the lateral femoral wall and ideal tip-apex distance are important predictive factors in the future of these fractures treated by gamma nails in terms of healing and complication rates. Methods: The radiological and clinical outcomes of 35 fractures of this type treated by short and long gamma nail from June 2014 to April 2021 were retrospectively reviewed. The elements considered were the quality of the lateral femoral wall reduction, the tip-apex distance (TAD), the lag screw position and overall quality reduction using the Baumgaertner criteria. Union, nonunion, cutout, screw sliding, nail or screw breakage were also radiographically evaluated during follow-up. Results: The union rate was 97%. A significant association was not observed between the state of reduction of the lateral wall and the three types of complications considered (cutout: p=0.31; sliding screw: p=1.00; varus displacement: p=0.30), and the linear regression model obtained indicates that in subjects with a non-reduction of the lateral wall, the consolidation time is increased on average by approximately 3 months (β= 2.99; 95%CI: 1.79-4.20, p&lt;0.001). No significant association was found between TAD and complications (cut-out: p=1.00; sliding screw: p=1.00; varus displacement: p=0.13). Conclusion: Anatomic reduction of the lateral wall and an ideal TAD ≤ 25mm might not be as significant for 31A3 fractures treated with gamma nails. Acceptable reduction of the lateral wall and stable internal fixation are sufficient elements to achieve fracture healing and functional recovery.

A Retrospective Study of 98 Elderly Patients with High-Risk Lateral Femoral Wall Intertrochanteric Hip Fractures to Compare Outcomes Following Surgery with Proximal Femoral Nail Antirotation (PFNA) Versus Dynamic Hip Screw (DHS).

BackgroundThe aim of this study was to evaluate the efficacy of dynamic hip screw (DHS) and femoral nail antirotation (PFNA) in the treatment of lateral-wall high-risk type of intertrochanteric fractures.Material/MethodsA total of 98 patients with high-risk intertrochanteric fractures of the lateral wall who underwent surgery from January 2019 to December 2020 were selected as the study subjects. Of these, 52 were treated surgically with PFNA (mean age 73.45±5.95 years) and 46 with DHS (71.37±6.22 years). We followed up these patients and compared the occurrence of the 2 surgical methods in terms of perioperative period, complication rate, and functional recovery.ResultsIn terms of lateral wall fracture, there were 2 cases of PFNA and 10 cases of DHS, and the difference between groups was statistically significant (P<0.05). Operative time (mean 54.94±7.29 vs 61.17±6.45) and intraoperative blood loss (72.80±9.18 vs 96.12±8.22) was significantly lower in the PFNA group compared to the DHS group (all P<0.05). Efficacy in the PFNA group was significantly better than in the DHS group. The HHS at follow-up was significantly higher in the PFNA group (mean 80.73±9.20 vs 64.19±8.12) than in the DHS group (P<0.001). The VAS score at follow-up was significantly lower in the PFNA group (1.78±0.34 vs 2.65±0.23) than in the DHS group (P<0.001).ConclusionsPFNA is more effective than DHS in the treatment of high-risk lateral wall fractures in the elderly, with the advantages of lower incidence of complications and better recovery of hip joint function. PFNA warrants clinical application.

Reliability of the lateral femoral wall thickness for detecting the potential for treatment failure and implant choice in patients with trochanteric hip fractures: a prospective cohort study

Background: Trochanteric hip fractures represent one of the most challenging injuries in orthopaedic practice. Dynamic hip screw (DHS) remains the gold standard in management of these fractures. Lateral femoral wall thickness (LWT) is an evolving parameter for detecting the potential for lateral wall fracture. The aim of this study was to determine the mean and cutoff levels for LWT that warrant lateral wall fracture and its various implications. Methods: This prospective cohort study included 42 patients with trochanteric hip fractures treated with DHS. LWT was assessed in all patients preoperatively. Patients were divided into two groups according to the postoperative integrity of the lateral femoral wall; in group A the patients sustained a lateral femoral wall fracture, and in group B the lateral femoral wall remained intact. All patients were regularly followed up for 12 mo. Results: At 12 mo, 12% of patients suffered postoperative lateral wall fracture, while in 88% the lateral femoral wall remained intact. The mean LWT in group A was 18.04 mm compared to 26.22 mm in group B. Revision surgery was 40% in group A and 5% in group B. The cutoff point of LWT below which there is a high chance of postoperative lateral wall fracture when fixed with DHS was 19.6 mm. Conclusions: Preoperative measurement of LWT in elderly patients with trochanteric hip fractures is decisive. The cutoff point for postoperative lateral wall fracture according to this study was 19.6 mm; hence, intramedullary fixation should be considered in this situation. Level of Evidence: Level II.

Association between lateral femoral wall thickness and BMD with the occurrence of lateral wall fracture in DHS fixation

BackgroundNearly 50% of all hip fractures are intertrochanteric fractures (ITF) and are linked to osteopenia and advancing age. For secure ITF repair, the dynamic hip screw (DHS) fixation is regarded gold standard surgery. However, controversy exists regarding the use of DHS in the treatment of unstable ITF especially in patients with pre-operative lateral femoral wall fracture (LWF). The purpose of this study is to find if there's a link between lateral femoral wall thickness, bone mineral density and the risk of LWF in DHS fixation. Patient and methodsA prospective, observational cohort analysis of 70 consecutive patients with ITF was undertaken in a tertiary care government hospital. All patients were treated with a 135° DHS fixation under regional anaesthesia and fluoroscopic guidance. Lateral femoral wall thickness was assessed pre-operatively on radiographs and during surgery. Mean T score as a measure of bone mineral density was recorded in all patients. ResultPostoperative LWFs occurred in 11 individuals. In 11 patients who had a postoperative LWF, the mean lateral femoral wall thickness was 19.545 mm, while the remaining 54 patients had a mean lateral femoral wall thickness of 29.285 mm (P < 0.001) With 81.5% sensitivity, the lateral femoral wall thickness threshold that could predict LWF was determined to be less than 25 mm. The mean T score of the contralateral hip in LWF patients was −2.255 standard deviation, whereas it was −2.428 standard deviation in patients without LWF, the difference of which was statistically not significant. ConclusionDHS fixation alone should be avoided in ITF patients with lateral femoral wall thickness <25 mm and other implant choices should be explored for management of these patients.

The lateral femoral wall thickness on the risk of post-operative lateral wall fracture in intertrochanteric fracture after DHS fixation: A finite element analysis

BackgroundPatients with a lateral femoral wall (LFW) fracture were reported to have high rates of re-operation and complication. Although the LFW thickness was a reliable predictor of post-operative or intra-operative LFW fracture, there was a paucity of literature evaluating the critical stress distributions on the femur and screws of intertrochanteric fractures treated with dynamic hip screw (DHS). This study aimed to investigate the biomechanical performance of intertrochanteric fractures with different LFW thickness treated with DHS device. MethodsA three-dimensional model of the proximal femur was established by computed tomography images. The intertrochanteric fracture model with three different LFW thickness (10 mm, 20.5 mm and 30 mm, respectively) was created, which was fixed by DHS. The von Mises stress on the proximal femur, lateral femoral wall, DHS and the total displacement of the device components were evaluated and compared for three different LFW thickness model. ResultsThe maximum von Mises stress in the proximal fragment of the 10 and 20.5 mm model increased by 80.56% and 57.97% when compared with the 30 mm model. The peek von Mises stress around the blade entry point of the 10 mm and 20.5 mm model increased by 89.26% and 66.39% when compared with the 30 mm model. The peek von Mises in the DHS located near the junction of the barrel and side plate of each model and the 30 mm model had the smallest von Mises stress compared with the other two models. Furthermore, the maximum displacement in the 30 mm model was much smaller than that in the10mm model and 20 mm model. ConclusionsThe intertrochanteric fracture with a thinner LFW tended to have a higher risk of LFW fracture stabilized by a DHS device. Thus, the intertrochanteric fractures with a thinner LFW should not be treated by DHS alone and the intramedullary nail or an addition of trochanteric stabilization plate(TSP) was recommended.

Risk of proximal femoral nail antirotation (PFNA) implant failure upon different lateral femoral wall thickness in intertrochanteric fracture: a finite element analysis

Proximal Femoral Nail Antirotation (PFNA) has been commonly used to treat intertrochanteric fractures, despite the risk of implant failure. The integrity of the femur could influence the risk of implant failure. This study evaluated the influence of lateral femoral wall thickness on the potential of implant failure. A finite element model of the hip was reconstructed from the Computed Tomography of a female patient. Five intertrochanteric fracture models at different lateral femoral wall thickness (T1 = 27.6 mm, T2 = 25.4 mm, T3 = 23.4 mm, T4 = 21.4 mm, and T5 = 19.3 mm) were then created and fixed with PFNA. We simulated a critical loading condition by a high loading case during walking. Elastoplastic material models with yield stress and failure strain were applied to the bone and implant in which breakage can be simulated using the element deletion function. In addition, the stress and displacement of the implant and femur were analysed. Implant breakage occurred at the sides of the proximal nail canal in cases of T4 and T5 which was further supported by the higher maximum von Mises stress and nail displacement. The increased stress and displacement of the implant may implicate a reduction of stability and risk of implant failure. We suggested that precaution shall be taken when the wall thickness was less than 21.4 mm.

Risk factors for implant failure of intertrochanteric fractures with lateral femoral wall fracture after intramedullary nail fixation

IntroductionFew studies have specifically evaluated the comminution extent of lateral femoral wall (LFW) fracture and risk factors of implant failure in intertrochanteric fractures with LFW fracture. The aim of present study was to evaluate the influence of comminution extent of LFW fracture on implant failure and identify risk factors of implant failure in cases with LFW fracture after intramedullary fixation. MethodsThis retrospective study included 130 intertrochanteric fracture with LFW fracture treated with intramedullary fixation at a teaching hospital over a 13-year period from January 2006 to December 2018. Demographic information, cortical thickness index, the reduction quality, status of medial support, position of the screw/blade and status of lateral femoral wall were collected and compared. The logistic regression analyzes was performed to evaluate risk factors of implant failure in intertrochanteric fractures with LFW fracture after intramedullary nail fixation. Results10 patients (7.69%) suffered from mechanical failure after intramedullary fixation. Univariate analyzes showed that comminuted LFW fracture (OR, 7.625; 95%CI, 1.437~40.446; p = 0.017), poor reduction quality (OR, 49.375; 95%CI, 7.217~337.804; p < 0.001) and loss of medial support (OR, 17.818; 95%CI, 3.537~89.768; p < 0.001) were associated with implant failure. After adjustment for confounding variables, the multivariable logistic regression analyzes showed that poor reduction quality (OR, 11.318; 95%CI, 1.126~113.755; p = 0.039) and loss of medial support (OR, 7.734; 95%CI, 1.062~56.327; p = 0.043) were independent risk factors for implant failure. Whereas, comminuted LFW fracture was not associated with implant failure (p = 0.429). ConclusionsThe comminution extent of the LFW fracture might influence the stability of intertrochanteric fractures; and intramedullary fixation might be an effective treatment method. Furthermore, poor reduction quality and loss of medial support could increaze the risk of implant failure in intertrochanteric fractures with LFW fractures after intramedullary fixation. Therefore, we should pay great emphasis on fracture reduction quality in future.

Positive or negative anteromedial cortical support of unstable pertrochanteric femoral fractures: A finite element analysis study

ObjectiveTo explore the mechanical stability of unstable pertrochanteric fractures with proximal femoral nail anti-rotation (PFNA-Ⅱ) fixation under different anteromedial cortical support reduction patterns. MethodsA 65-year-old healthy male volunteer with no history of hip or systemic disease was recruited. High-resolution computed tomography images with a slice thickness of 0.67 mm of his right femur were obtained. These images were used to establish three-dimensional (3D) models. The lesser trochanter and lateral femoral wall were cut off to create an AO Foundation/Orthopaedic Trauma Association type 31-A2 unstable pertrochanteric fracture model. PFNA-Ⅱ was used to simulate fixation. Nine different fracture reduction patterns, which included positive-positive, positive-neutral, positive-negative, neutral-positive, neutral-neutral, neutral-negative, negative-positive, negative-neutral, and negative-negative cortical support reductions, were simulated. A load of 700 N was applied to simulate a 70 kg elderly patient standing on one leg. The models were subjected to finite element analysis. The displacement and von Mises stress distributions were analyzed. ResultsThe positive-positive cortical support reduction pattern showed minimal stress and the negative-negative reduction pattern showed maximal stress on the intramedullary nail. The stress was mainly concentrated at the junction of the helical blade and the main nail and at the site of the lateral aspect of the insertion point of the nail in the great trochanter. The positive cortical support reduction patterns seemed to have smaller maximum displacements of the entire fragment-implant assembly and relative displacements between the head-neck and shaft fragments. Meanwhile, the negative reduction patterns seemed to have larger displacements. ConclusionThe positive-positive support reduction pattern showed better mechanical stability for unstable pertrochanteric fractures. The negative-negative support reduction pattern was prone to fixation failure and should be avoided during an operation.

The Importance of the Lateral Femoral Wall Thickness in Intertrochanteric Fracture: Educational Corner

The article's abstract is not available.

Various factors influencing the outcome in DHS fixation of Intertrochanteric fractures

Background: Dynamic hip screw (DHS) is a standard device for intertrochanteric fractures (ITF). Implant failure in form of screw cut out leading to varus collapse of neck shaft angle is associated with various factors like bone quality, fracture pattern, fracture reduction, lateral femoral wall thickness (LFWT), screw position and tip-apex distance (TAD). But there has been no clear consensus to the relative importance of each factor. The purpose of our study is to assess individual factors for a favorable outcome in DHS fixation of ITF. Materials and methods: 121 hips sustaining ITF treated with DHS between June 2014 and July 2016 were reviewed in our prospective study with a mean period of 12 months. Factors under study were bone quality,fracture pattern, fracture reduction, LFWT, screw position and TAD, which were recorded and used for statistical analysis using SPSS. Chi-square test, Independent t-test and Paired t-test were used to evaluate the significance of the differences. Final analysis involved clinical and radiological assessment using Harris Hip Score (HHS) and radiographs respectively. Results and Analysis: The mean age of patient at the time of surgery was 65.27±3.21 years (range 24-85) with 80 males and 41 females. There was no statistical significant relation found between implant failure and osteoporosis even though cases of failure were found in weak osteoporotic bones. Implant failure in relation to unstable fracture pattern, non-anatomical fracture reduction, LFWT< 21.77 mm, screw placement in position apart from centre or centre-inferior and TAD greater than 25mm was found to be statistically significant (p<0.05).The final functional and radiological assessment revealed 68.85% and 86.88% of hips respectively in good to excellent category. Conclusion: DHS is a well-accepted implant for ITF with lower rate of complications only if proper surgical technique is followed. Good fracture reduction, adequate LFWT, ideal screw position and TAD less than 25mm are must to prevent implant failure. Level of Evidence: Level IV Keywords: Intertrochanteric fractures, DHS, Factors for failure