Reverse Oblique Intertrochanteric Fractures Research Articles

Biomechanical comparison of femoral neck anti-rotation and support system versus femoral neck system for unstable pauwels III femoral neck fractures

BackgroundThe optimal treatment method for managing unstable Pauwels III femoral neck fractures remains undetermined. The aim of this study was to compare the biomechanical properties of two types of Femoral Neck Anti-rotation and Support System (FNAS) and a Femoral Neck System (FNS) in unstable Pauwels III femoral neck fractures.MethodsEighteen synthetic femoral models were implanted with one of three fixation devices: FNS, FNAS I, or FNAS II. An unstable Pauwels III (OTA/AO 31-B2.3) femoral neck fracture was simulated using a custom-made needle and osteotomy guide. Torsion and axial compression loading tests were conducted, and the torque, torsion angle, load to failure, displacement, and stiffness values were recorded.ResultsFNAS II exhibited significantly higher torsional stiffness (0.67 ± 0.10 Nm/°) compared to FNAS I (0.52 ± 0.07 Nm/°, P = 0.01) and FNS (0.54 ± 0.07 Nm/°, P = 0.005). FNS demonstrated significantly greater mean axial stiffness (239.24 ± 11.38 N/mm) than both FNAS I (179.33 ± 31.11 N/mm, P = 0.005) and FNAS II (190.07 ± 34.11 N/mm, P = 0.022). FNAS I (302.37 ± 33.88 N/mm, P = 0.001) and FNAS II (319.59 ± 50.10 N/mm, P < 0.001) showed significantly higher initial axial stiffness compared to FNS (197.08 ± 33.68 N/mm). Both FNAS I and II improved resistance to deforming forces at a load level before approximately 1000 N, which is sufficient to withstand the load from most daily life activities. No significant differences were observed in compression failure load among the groups. The failure patterns at the point of failure included the pull-out of the distal locking screw and reverse oblique intertrochanteric femur fracture for FNS, while for FNAS I and II, the failures were characterized by a cleft on the calcar femorale and a decrease in the load–displacement curve.ConclusionsIn unstable Pauwels III femoral neck fractures, the FNAS II enhances stability and is easier to manage for reoperation. The results of the current study support the potential of FNAS II as an alternative option for treating unstable Pauwels III femoral neck fractures in young individuals.

Comparative study of a novel proximal femoral bionic nail and three conventional cephalomedullary nails for reverse obliquity intertrochanteric fractures: a finite element analysis

Comparative study of a novel proximal femoral bionic nail and three conventional cephalomedullary nails for reverse obliquity intertrochanteric fractures: a finite element analysis

No Difference in Clinical and Hospital Quality Outcomes in Treatment of Reverse Obliquity Intertrochanteric Hip Fractures (AO/OTA 31.A3) Based on Cephalomedullary Nail Length

IntroductionThe purpose of this study was to evaluate outcomes following reverse obliquity (RO) intertrochanteric hip fractures based on the use of short cephalomedullary nails (CMNs) compared to long CMNs for fixation. MethodsAn IRB-approved prospectively collected hip fracture registry at an urban academic medical center was queried for all AO/OTA 31A3.1-3 reverse obliquity intertrochanteric (RO) fractures. One hundred and seventy patients with age > 55 years old and minimum 6-month follow-up were identified for analysis. Data was collected for patient demographics, injury details, intraoperative radiographic parameters, perioperative physiologic parameters, hospital quality measures, and outcomes including radiographic time to healing, need for reoperation, nonunion, and mortality. Comparative analyses were conducted between cohorts. Additional multivariable binary logistic and linear regression analyses were performed to evaluate for factors independently associated with short and long nail usage. ResultsThe mean age of the entire cohort was 80.91±10.09 years: 103 patients had a long CMN implanted, and 67 patients had a short CMN implanted. There were no demographic differences or differences in radiographic time to healing, rates of mortality, readmission, nonunion, and need for reoperation. Univariable analysis revealed that short CMN had lower intraoperative blood loss (111.19±83.97mL vs 176.72±161.45mL, p=0.002), decreased need for transfusion (37% vs. 55%, p=0.022), and shorter procedures (118.67±57.87min vs. 148.95±77.83min, p=0.002. Multivariable analysis revealed that short nail usage was associated with decreased intraoperative blood loss, decreased need for transfusion, and shorter operative times. ConclusionNail length does not affect healing or hospital quality outcomes in the treatment of RO hip fractures. The use of short CMNs for these fractures did correlate with lower intraoperative blood loss, operative time, and need for blood transfusion, with non-inferior outcomes and similar hospital quality measures when compared to long CMNs.

Reverse oblique fracture needs more augmentation with IM nail: A use of trochanteric support plate (TSP)

Abstract Background: There are various type of unstable intertrochanteric femur fracture of which reverse oblique fracture is most challenging to fix because of its displacement. Reverse oblique fracture accounts for 1/3rd of all hip fractures and are very unstable. Posteromedial part is effectively support by intramedullary nail but fail to support broken lateral wall. Objective: A Prospective study to evaluate the comparative outcome of buttressing lateral wall with trochanteric support plate(Long PFN + TSP) &amp; without trochanteric support plate(long PFN alone). Materials and Methods: A study was carried out from 2018 to 2023; 60 cases of acute reverse oblique intertrochanteric femur fracture were studied, out of which 28 were treated with long PFN +TSP plate &amp; 32 were treated with Long PFN. Result: Bone healing is observed in all patient. Minimum average follow up of patients was 10.2 months. Patient treated with only Long PFN have mean bone healing time of 116.06 days whereas patients treated with Long PFN + TSP plate have mean time of 61.56 days. Conclusion: With proper pre operative planning, with anatomical/acceptable reduction long PFN + TSP plate is an ideal modality for reverse oblique intertrochanteric femur fracture.

Posterolateral wall integrity in reverse oblique intertrochanteric fracture fixation: A new perspective in evaluation.

Treatment of reverse oblique fractures has the highest complication rate among proximal femur fractures. Although intramedullary nailing is the preferred treatment option, a high failure rate has been reported. Previous studies have identified several contributing factors to these failures, yet the significance of posterolateral wall integrity in ensuring postoperative stability has not been emphasized. This study aims to investigate the impact of posterolateral wall integrity on the failure rates of reverse oblique intertrochanteric fractures treated with intramedullary nails (IMN) and assess the vulnerability of certain IMN designs to these failures. Between 2010 and 2016, 53 patients with reverse oblique fractures were analyzed to identify factors associated with IMN failure. Variables such as posterolateral wall integrity, quality of reduction, posteromedial support, and IMN design were considered as potential risk factors. Logistic regression analysis was conducted to evaluate these risk factors, with statistical significance defined as p<0.05. Eleven cases of implant failure were identified. Univariate statistical analysis indicated that loss of posterolateral support (p=0.002), IMN with single-screw proximal fixation (p=0.048), poor reduction quality (p=0.004), and loss of posteromedial support (p=0.040) were associated with implant failure. Multivariate analysis confirmed loss of posterolateral support (p=0.009), poor reduction quality (p=0.039), and loss of posteromedial support (p=0.020) as independent risk factors for failure. However, IMN with single proximal fixation (p=0.859) did not significantly impact fixation failure. Reverse oblique intertrochanteric fractures with compromised posterolateral support exhibit a high rate of mechanical failure when treated with IMN. Additionally, poor reduction quality and loss of posteromedial support increase the risk for failure of these fractures. An IMN design featuring dual separate proximal screw fixations could provide better stability compared to a design with a single proximal screw, thereby reducing the risk of mechanical failure.

Comparison of Proximal Femoral Nail versus Dynamic Condylar Screw in Treating Reverse Oblique Intertrochanteric Femoral Fractures

Aim: Comparison of proximal femoral nail versus dynamic condylar screw in treating reverse oblique intertrochanteric femoral fractures. Study Design: Retrospective study Place and duration of study: CMH Kharian, Allama Iqbal International Hospital Kharian and Madni Hospital Gujrat from 1st January 2020 to 31st December 2022. Methodology: Sixty five patients who had suffered from reverse oblique intertrochanteric femoral fractures and were either treated through proximal femoral nail or by dynamic condylar screw were included. Patients who were treated with proximal femoral nail were placed in group 1 while those treated with dynamic condylar screw were placed in group 2. The comparative outcomes between both groups were than analyzed and documented in a well-structured questionnaire. Results: There was no significant variance in the mean age of the patients in group 1 (proximal femoral nail) and group 2 (dynamic condylar screw) with a value as 65.53±3.1 and 59.35±3.2 years respectively. There were more females in both groups than males however with no significant variance. Non-union and implant breakage observed in the dynamic condylar screw cases were 5/32 and PFN cases 2/33 respectively; with a significant p value difference. The fixation revision was required in 5case with dynamic condylar screw implant failure while it was 2 in cases of proximal femoral nail. The rate of infection was higher in dynamic condylar screw patients. Practical Implication: There was no advantage of open reduction by dynamic condylar screw over the closed proximal femoral nail reduction. Proximal femoral nail reduction and fixation presented to be a better option for treating reverse oblique intertrochanteric femoral fractures. Conclusion:A high rate of non-union is presented in dynamic condylar screw treated cases.Proximal femoral nail fixation presented to be a better option for treating reverse oblique intertrochanteric Femoral Fractures Keywords: Intertrochanteric, Intramedullary, Femur, Reverse Oblique fractures

Reduced cutout for reverse oblique intertrochanteric hip fractures treated with trochanteric fixation advanced (TFN-A) nail compared to the short gamma-3 nail.

Reverse oblique fractures (AO/OTA 31-A3) account for 5-23% of all intertrochanteric fractures and are challenging to manage. The Gamma 3-Proximal Femoral Nail (GPFN) and the Trochanteric Fixation Nail Advanced (TFNA) are two common cephalomedullary systems used to treat this fracture. No study has reported on outcomes with the TFN-A for reverse oblique fractures. This study aimed to compare outcomes and complication rates in patients with reverse oblique fractures, treated with either TFNA or GPFN. A total of 203 patients with reverse oblique fractures (137 in the GPFN group and 66 in the TFNA group), were treated in our institution between June 2010 and May 2019. Data was collected on postoperative radiological variables including screw or blade location, and tip-apex distance (TAD). Data were also collected for non-orthopaedic complication rates and orthopaedic complications. A sub-group analysis was additionally performed for different nail lengths. We found no significant difference in the overall rate of complications and revisions between the two groups. Patients treated with the 235mm TFN-A nail sustained lower rates of cutout, compared to 180mm GPFN (GPFN: 6% TFN-A: 0%, p=0.043). The frequency of revision surgeries and malunions/non-unions did not differ significantly between the two groups and additionally showed no difference in the subgroup analysis. The 235mm TFN-A was associated with lower rates of cut-out compared to the short GPFN for reverse oblique intertrochanteric fractures. Future well-designed prospective studies are warranted to investigate the role of the TFN-A in improving outcomes for such fractures.

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

Reverse oblique intertrochanteric fractures are classified by the Orthopaedic Trauma Association [OTA]/[AO] as 31A3, and account for up to one-third of all hip fractures, and 2-23% of all trochanteric fractures. The treatment of choice of those fractures is intramedullary nailing as it decreases soft tissue damage and permits early weight bearing. A retrospective comparative study was conducted on patients surgically treated for 31A3 fractures from October 2018 to January 2022 in a high-volume regional referral centre. All the patients had been treated with intramedullary nailing. The selected group included 11 males (16%) and 59 females (84%), with a mean age of 83.6 years (range 61 to 96 years). A Trigen Intertan Nail was the most frequent choice of intramedullary nailing in 33 patients (47%), an Elos Long nail was chosen in 19 cases (27%), while a ZNN nail was used in 18 patients (26%). The mean time between admission and surgery was 2.5 days, with a mean Hb value of 10.5 g/dl reported preoperatively. Patients treated with an Intertan nail reported the lowest TAD, CALTAD, and TALCALTAD mean radiographic values, and the lowest rate of Hb loss and blood transfusions.

Reverse Obliquity Intertrochanteric Fracture Treated with a Dynamic Distal Locked Intramedullary Hip Nail.

The aim of this study was to describe the clinical and radiological results of reverse obliquity intertrochanteric fractures treated with dynamic distal locked intramedullary hip nails. Patients with a reverse obliquity intertrochanteric fracture (AO/OTA type 31 A3.1 or A3.3) underwent surgical treatment with a dynamic distal locked intramedullary hip nail between August 2017 and September 2020. Fracture type, reduction quality, change in the position of the distal bone fragment, bone union, complications, and walking ability were evaluated. Ten patients with reverse obliquity intertrochanteric fractures (seven females and three males) underwent dynamic distal locked intramedullary hip nailing. The mean age was 72.0 ± 18.9 years. Two patients were classi fied as having A3.1 fractures; eight patients were classified as having A3.3 fractures. Anatomical reduction was achieved in six patients, medial displacement remained in three patients, and lateral displacement remained in one patient postoperatively. In 9 out of 10 patients, the center of the proximal end of the distal bone fragment had moved laterally between the time immediately after surgery and the time of the final evaluation. Bone union was obtained uneventfully without any additional treatments in all patients. There were no complications such as infection or implant failure. Walking ability decreased in four patients. In all patients, bone union was achieved due to good contact of the medial cortices or the migration of the distal bone fragment into the proximal bone fragment. This procedure can be an option for treating reverse obliquity intertrochanteric fractures.

Risk factors for over-telescoping in reverse oblique intertrochanteric fractures.

Postoperative over-telescoping (OT) with lag screws is often observed in reverse oblique intertrochanteric fractures. This study aimed to clarify the risk factors of OT in patients with reverse oblique intertrochanteric fractures. Electronic medical records of patients diagnosed with reverse oblique intertrochanteric fractures using plain radiography who underwent operative fixation with an intramedullary nail between August 2013 and December 2019 were reviewed. Patients were classified into two groups according to the Futamura classification: lateral wall pattern (LW) and reverse oblique pattern (RO). The incidence of OT in the LW and RO groups was compared. Also, we compared the incidence of OT for each reduction type in the LW group. Twenty patients had LW, and nine had RO. OT was observed in eight fractures (42.1%) in the LW group but not in the RO group. The incidence of OT was significantly higher in the LW group than in the RO group (P = 0.0261). Among the 19 fractures with LW, OT was observed in 7 of 10 and 1 of 9 fractures with postoperative reduction in the intramedullary and extramedullary or anatomical types, respectively. In the LW group, the incidence of OT was significantly higher in fractures with postoperative reduction in the intramedullary type than in those of the extramedullary or anatomical type (P = 0.0198). Our study showed that the incidence of OT was significantly higher in LW than in RO and that postoperative reduction in the intramedullary type in LW was a risk factor for OT.

Biomechanical study of extramedullary and intramedullary fixation in the treatment of unstable intertrochanteric reversed-tilt fractures of the femur.

BackgroundTo investigate the efficacy of the 135° hip screw, 95° intramedullary hip screw (IMHS) and 95° hip screw in the treatment of intertrochanteric reverse dip fracture of the femur.MethodsWe retrospectively analyzed 125 matched pairs of human femurs (median age 64 years) which were osteotomized at a 33° angle in the left femur and extended downward from the minor trochanter to simulate a reverse oblique intertrochanteric fracture. The right femur served as a control. The left femur (n=4) was implanted with a 135° hip screw, 95° hip screw, or IMHS. A strain detector was placed distal to the fracture site to monitor fragment strain. The lateral displacement of the proximal femur was measured by a linear variable differential transformer. An Instron tester measured stiffness, strain, and lateral displacement at 25° adduction, and 90° adduction with vertical loads on the femoral head. A 2 cm gap was then formed at the fracture site to simulate comminution and the mechanical test was repeated.ResultsBefore the formation of the gap, there was no significant difference in stiffness among different bone structures (P>0.05), but after the formation of the gap, the stiffness of all the adduction structures decreased (P=0.03), and the difference in adduction was statistically significant (135° hip screw: 46.6%±3%; 95° hip screw: 22.9%±2%; IMHS: 53.7%±7.8%; P<0.05). Similar results were found for the abduction and buckling positions. There was no significant difference in the lateral displacement of the gap before (P=0.92) and after (P=0.26), but a significant difference in the failure load was found (135° hip screw: 1,222±560 N; 95° hip screw: 2,566±283 N; IMHS: 4,644±518 N; P=0.02).ConclusionsThere was no statistically significant difference in stiffness among different structures (P>0.05). However, in the presence of gaps, IMHS bone implant structures are much stiffer than 135° and 95° structures and have a greater destructive load.

Expandable Proximal Femoral Nail versus Gamma Proximal Femoral Nail for the treatment of hip reverse oblique fractures.

Reverse oblique intertrochanteric fractures are classified by the AO/OTA as 31A3 and account for 2-23% of all trochanteric fractures. The Gamma 3-Proximal Femoral Nail (GPFN) and the Expendable Proximal Femoral Nail (EPFN) are among the various devises used to treat this fracture. The aim of this study was to compare outcomes and complication rates in patients with AO/OTA 31A1-3 fractures, treated by either a GPFN or an EPFN. A total of 67 patients (40 in the GPFN group and 27 in the EPFN group, average age 78.8years) were treated in our institution between July 2008 and February 2016. Data on postoperative radiological variables, including peg location and tip-apex distance (TAD), as well as orthopedic complications, such as union rate, surgical wound infection and cut-outs rates were also recorded, along with the incidence of non-orthopedic complications and more surgical data. Functional results were evaluated and quantified using the Modified Harris Hip Score (MHHS) and by the Short Form 12 Mental Health Composite questionnaire (SF-12 MHC) in order to assess the quality of life. The total prevalence of postoperative orthopedic complications including postoperative infection showed a significant difference with a p-value of 0.016 in favor of the EPFN group. Nonetheless, the frequency of revision did not differ between the two groups, being 0.134. The main orthopedic complication in both groups was head cut-out of the GPFN lag screw and the EPFN expendable peg, which was 20% and 7.4%, respectively, and required a revision surgery using a long nail or total hip replacement (THR). However, the average TAD did not significantly differ between groups which might be due to a relatively low cohort to reach a significant difference. Nonunion rate of 5% occurred solely in the GPFN group, with similar results of intraoperative open reduction between both groups. The EPFN group achieved better scores in both questionnaires (p = 0.027 and p = 0.046, respectively). Both the MHHS and SF-12 MCS values significantly differed between groups, with the EPFN group achieving better scores than the GPFN group in both questionnaires (p = 0.027 and p < 0.05, respectively). According to this study, the EPFN yields better results in comparison with the GPFN, with relatively less complications rate, for the treatment of unstable reverse oblique pertrochanteric fracture. In light of this results, we conclude that the EPFN might be as good as GPFN for the treatment of reverse oblique intertrochanteric fractures. Level III retrospective study. The local institutional review board of the Tel Aviv Medical Center approved this study and all the surgeries were done exclusively in this institution.

Medial support nail and proximal femoral nail antirotation in the treatment of reverse obliquity inter-trochanteric fractures (Arbeitsgemeinschaft fur Osteosynthesfrogen/Orthopedic Trauma Association 31-A3.1): a finite-element analysis

BackgroundThe reverse obliquity inter-trochanteric fracture is a distinct fracture pattern that is mechanically different from most inter-trochanteric fractures and the optional treatment of it is still controversial. The purpose of this study was to compare differences in the efficacy of a novel nail (medial support nail [MSN-II]) and proximal femoral nail anti-rotation (PFNA-II) in the treatment of reverse obliquity inter-trochanteric fractures (Arbeitsgemeinschaft fur Osteosynthesfrogen/Orthopedic Trauma Association [AO/OTA] 31-A3.1) using finite-element analysis.MethodsModeling software was used to establish a three-dimensional model of MSN-II and PFNA-II and an A3.1 inter-trochanteric fracture model. Abaqus software was used to implement different force loads to compare finite-element biomechanical parameters such as the maximum stress in implant and the displacement of fracture site.ResultsThe femoral stress, implant stress and fracture site displacement of MSN-II was less than that of PFNA-II. The results indicated that the maximal femoral stress was 581 MPa for PFNA-II and 443 MPa for the MSN-II. The maximum stress values in the PFNA-II and MSN-II models were 291 and 241 MPa, respectively. The maximal displacements of the fracture site were 1.47 and 1.16 mm in the PFNA-II and MSN-II models, respectively.ConclusionCompared with PFNA-II for inter-trochanteric fracture (AO/OTA 31-A3.1), MSN-II which was designed with a triangular stability structure can provide better biomechanical stability. The MSN-II may be a feasible option for the treatment of reverse obliquity inter-trochanteric fracture.

Finite element analysis of two cephalomedullary nails in treatment of elderly reverse obliquity intertrochanteric fractures: zimmer natural nail and proximal femoral nail antirotation-\u0399\u0399

BackgroundMore elderly patients are suffering from intertrochanteric fractures. However, the choice of internal fixation is still controversial, especially in the treatment of unstable intertrochanteric fracture; thus, previous implants continue to be improved, and new ones are being developed. The purpose of our study was to compare the biomechanical advantages between the zimmer natural nail (ZNN) and proximal femoral nail antirotation-II (PFNA-II) in the treatment of elderly reverse obliquity intertrochanteric fractures.MethodsA three-dimensional finite element was applied for reverse obliquity intertrochanteric fracture models (AO31-A3.1) fixed with the ZNN or PFNA-II. The distribution, peak value and position of the von Mises stress and the displacement were the criteria for comparison between the two groups.ResultsThe stresses of the internal fixation and femur in the ZNN model were smaller than those in the PFNA-II model, and the peak values of the two groups were 364.8 MPa and 171.8 MPa (ZNN) and 832.3 MPa and 1795.0 MPa (PFNA-II). The maximum amount of displacement of the two groups was similar, and their locations were the same, i.e., in the femoral head vertex (3.768 mm in the ZNN model and 3.713 mm in the PFNA-II model).ConclusionsThe displacement in the two models was similar, but the stresses in the implant and bone were reduced with the ZNN. Therefore, the ZNN implant may provide biomechanical advantages over PFNA-II in reverse obliquity intertrochanteric fractures, as shown through the finite element analysis. These findings from our study may provide a reference for the perioperative selection of internal fixations.

Comparison of Third Generation Proximal Femoral Nails in Treatment of Reverse Oblique Intertrochanteric Fractures

Comparison of Third Generation Proximal Femoral Nails in Treatment of Reverse Oblique Intertrochanteric Fractures

Comparative study of intramedullary nailing in reverse obliquity intertrochanteric fractures with or without Cerclage wire augmentation

Comparative study of intramedullary nailing in reverse obliquity intertrochanteric fractures with or without Cerclage wire augmentation

Correction to: A biomechanical comparison of three fixation techniques in osteoporotic reverse oblique intertrochanteric femur fracture with fragmented lateral cortex.

This study was done with the financial support of the Istanbul University Scientific Research Projects.

A biomechanical comparison of three fixation techniques in osteoporotic reverse oblique intertrochanteric femur fracture with fragmented lateral cortex.

The treatment of the reverse oblique osteoporotic femur fractures is still problematic and can be complicated especially that are accompanied by a fragmented lateral cortex. The aim of this study was to compare three different internal fixation methods in the osteosynthesis of osteoporotic reverse oblique intertrochanteric femur fracture models with a fragmented lateral cortex. Biomechanical experiment study. A total of 24 osteoporotic femur models were obtained and divided into three groups [Group A: Proximal femoral nail(PFN), Group B: 95° angled blade plate (ABP), and Group C: proximal femoral anatomic locking plate (PFLP)] with each group which include eight bones. A standard fracture configuration was created as a reverse oblique intertrochanteric fracture and fixed with these implants. After fixation, all femur constructs were tested with an Instron 5800R tester (Instron, Canton, MA) in the biomechanics laboratory with axial loading and bending forces to assess axial and rotational stiffness and failure load. Displacement over 10mm and angulation greater than 10° in the fracture line were considered as failure. In all tests, ABP had statistically poorer results in comparison to the PFN and PFLP group. PFLP fixation had better biomechanical fixation results in comparison to the PFN group, although the results were not statistically significant. Orthopaedic surgeons should keep in mind that lateral cortex comminution brings further instability to these reverse oblique intertrochanteric osteoporotic fractures and high rates of failure may be encountered due to this instability. PFLP fixation may be an alternative fixation method biomechanically for these instable fractures.

Embedding the lateral end of the lag screw within the lateral wall in the repair of reverse obliquity intertrochanteric femur fracture.

ObjectiveThe management of reverse oblique intertrochanteric femoral fractures is difficult because such fractures have unique biomechanical characteristics. This study was performed to review the results of treating reverse oblique intertrochanteric femoral fractures with a long cephalomedullary nail by embedding the lateral end of the lag screw to secure axial compression.MethodsWe herein report the surgical outcomes in seven patients with reverse oblique intertrochanteric fractures treated with our procedure. Patients whose hip screws obviously had no contact with the distal fragment and whose follow-up time was too short were excluded. The lateral end of the lag screw was embedded within the lateral cortex, and the screws were locked to the nail. All nails were long, and a distal locking screw was inserted in the dynamized position.ResultsNo reoperation, definite leg length discrepancy, or malunion occurred in this study.ConclusionsThese data suggest that early complications do not seem to increase when the lateral end of the lag screw is embedded and the screw is locked to the nail in the treatment of reverse oblique intertrochanteric fracture at this stage.

Biomechanical assessment of newly-designed proximal femoral medial buttress plate for treatment of reverse oblique femoral intertrochanteric fracture

To evaluate the biomechanical properties of proximal femoral medial buttress plate (PFMBP) for fixing the reverse oblique intertrochanteric fractures by comparing with proximal femoral locking compression plate (PFLCP) and proximal femoral nail antirotation (PFNA). Eighteen synthetic femoral bone models (Synbone) were divided into 3 groups (group PFLCP, group PFNA, and group PFMBP), 6 models in each group; an AO 31-A3.1 reverse oblique femoral intertrochanteric fracture was made based on the same criterion. After being fixed and embeded, the axial load testing, torsion testing, and axial load-to-failure testing were performed on each model. The axial displacement of different loads, torque of different torsion angles, and failure load of each model were recorded, and the stiffness of axial load and torsion were calculated. The axial stiffness in groups PFLCP, PFNA, and PFMBP were (109.42±30.14), (119.13±29.14), and (162.05±22.05) N/mm respectively, showing significant differences between groups ( P<0.05). There were significant differences in torque between different torsion angles in the same group, as well as in the torque between groups at the same torsional angle ( P<0.05). The torsion stiffness in groups PFLCP, PFNA, and PFMBP were (1.45±0.44), (1.10±0.13), and (1.36±0.32) N·mm/deg respectively; there were significant differences when compared groups PFLCP and PFMBP with group PFNA ( P<0.05), but no significant difference was found between group PFLCP and group PFMBP ( P>0.05). The failure loads of groups PFLCP, PFNA, and PFMBP were (1 408.88± 0.17), (1 696.56±0.52), and (2 154.65±0.10) N respectively, showing significant differences between groups ( P<0.05). The newly-designed PFMBP is better than PFNA and PFLCP in axial load stiffness and torsion stiffness for fixing reverse oblique intertrochanteric fracture by biomechanical test, indicating that reconstruction of medial stability is a key element for unstable intertrochanteric fracture.