Characteristics and Treatment Strategies for Basicervical and Transcervical Shear Fractures of the Femoral Neck.

This study aimed to define basicervical and transcervical shear fractures using area classification and to determine the optimal osteosynthesis implants for them. The clinical outcomes of 1042 proximal femur fractures were investigated. A model of the proximal femur of a healthy adult was created from computed tomography images, and basicervical and transcervical shear fractures were established in the model. Osteosynthesis models were created using a short femoral nail with a single lag screw or two lag screws and a long femoral nail with a single lag screw or two lag screws. The minimum principal strains of the fracture surfaces were compared when the maximum loads during walking were applied to these models using finite element analysis software. Basicervical fractures accounted for 0.96% of all proximal femur fractures, 67% of which were treated with osteosynthesis; the failure rate was 0%. Transcervical shear fractures accounted for 9.6% of all proximal femur fractures, 24% of which were treated with osteosynthesis; the failure rate was 13%. Finite element analysis showed that transcervical shear fracture has high instability. To perform osteosynthesis, multiple screw insertions into the femoral head and careful postoperative management are required; joint replacement should be considered to achieve early mobility.

Structure-mechanical analysis of various fixation constructs for basicervical fractures of the proximal femur and clinical implications; finite element analysis.

OBJECTIVE: This present study was conducted to determine the structural-mechanical stability of various fixation constructs through finite element (FE) analysis following simulation of a basicervical fracture and to introduce the clinical implications. MATERIALS AND METHODS: We simulated fracture models by using a right synthetic femur (SAWBONES®). We imported the implant models into ANSYS® for placement in an optimal position. Five assembly models were constructed: (1) multiple cancellous screws (MCS), (2) FNS (femoral neck system®), (3) dynamic hip screw (DHS), (4) DHS with anti-rotation 7.0 screw (DHS + screw), and PFNA-II (Proximal Femoral Nail Antirotation-II®). The femur model's distal end was completely fixed and 7° abducted. We set the force vector at a 3° angle laterally and 15° posteriorly from the vertical ground. Analysis was done using Ansys® software with von Mises stress (VMS) in megapascals (MPa) and displacement (mm) RESULTS: The displacements of the proximal femur were 10.25 mm for MCS, 9.66 mm for DHS, 9.44 mm for DHS + screw, 9.86 mm for FNS, and 9.31 mm for PFNA-II. The maximum implant VMS was 148.94 MPa for MCS, 414.66 MPa for DHS, 385.59 MPa for DSH + screw, 464.07 MPa for FNS, and 505.07 MPa for PFNA-II. The maximum VMS at the fracture site was 621.13 MPa for MCS, 464.14 MPa for DHS, 64.51 MPa for DHS + screw, 344.54 MPa for FNS, and 647.49 MPa for PFNA-II. The maximum VMS at the fracture site was in the superior area with the high point around the posterior screw in the MCS, anterosuperior corner in the DHS, the posteroinferior site of the FNS, and posterosuperior site around the entry point in the PFNA-II. In the DHS + screw, the stresses were distributed evenly and disappeared at the maximum VMS fracture site. CONCLUSION: Based on the fracture site and implant's stress distribution, the model receiving the optimal load was a DHS + screw construct, and the FNS implant could be applied to anatomically reduced fractures without comminution. Considering the high-stress concentration around the entry point, a PFNA-II fixation has a high probability of head-neck fragment rotational instability.

Coronal shear fractures of the femoral neck: a comparison with basicervical fractures.

PURPOSE: We propose coronal shear fracture of the femoral neck (CSFF) as a new type of fracture that differs from a basicervical fracture. This study aimed to present the incidence of CSFF and compare its clinical characteristics and outcomes with those of basicervical fractures. METHODS: In this multicenter retrospective cohort study, 2207 patients with hip fractures were identified using computed tomography (CT), 17 and 27 patients were diagnosed with CSFF (CSFF group) and basicervical fractures (basicervical fracture group), respectively. The primary outcome was reoperation, while the secondary outcomes were postoperative radiographic findings, ambulatory ability, and 1-year mortality rate. These outcomes were compared between the two groups. We also conducted diagnostic reliability tests for these fractures using the Cohen's kappa coefficient. RESULTS: The incidence of CSFF and basicervical fractures in the 2207 patients were 0.77% and 1.22%, respectively. The inter-and intra-observer agreements for the diagnosis were almost perfect. The comorbidity score was significantly higher in the CSFF group than in the basicervical fracture group. No reoperations occurred in both groups. There were no significant intergroup differences in the postoperative radiographic findings. The 1-year mortality rate was higher in the CSFF group than in the basicervical fracture group (38.5% vs. 5.3%; odds ratio: 11.9, 95% CI: 1.2-118.5; p = 0.025). CONCLUSION: This study presents the definition and incidence of CSFF with a high diagnostic reliability. Patients with CSFF had similar reoperation rate postoperative radiographic outcomes to basicervical fractures, while 1-year mortality rate was high.

What is the most fixable intramedullary implant for basicervical fracture and transcervical shear fracture? - A finite element study.

Objective: The objectives of this study are 1) to biomechanically compare six different intramedullary fixations for basicervical fracture (AO 31-B3, Type 2 in area classification) and transcervical shear fracture (AO 31-B2.3, Type 1-2 in area classification) using the finite element (FE) method, and 2) to investigate the effects of two different unstable fracture types on fixation. Methods: FE models of two different types of proximal femoral fractures are constructed from CT scan images of a patient with osteoporosis. The fracture models are fixed with a short femoral nail with a single lag screw, short femoral nail with a single blade, and short femoral nail with double lag screws, and then fixed with long femoral nails for each of the three nail types. Subsequently, the maximum loads during walking and stair climbing, as well as the minimum principal strain and compressive failure elements are calculated to assess the fixation of each implant. Results: In both fracture types, the long nail with double lag screws show the smallest volume of compressive failure elements (basicervical fracture, 2 mm3; transcervical shear fracture, 217 mm3). In all types of implants, the volume of the compressive failure elements is larger in the transcervical shear fracture than in the basicervical fracture. A similar trend is observed for the minimum principal strain (compressive strain). Conclusion: The present study shows that a long nail with double lag screws is the most fixative intramedullary nail device for basicervical fracture and transcervical shear fracture in any condition. Furthermore, it is shown that transcervical shear fracture is considerably more unstable than basicervical fracture.

TresLock for Unstable Proximal Femoral Fractures: Morphological Compatibility and Clinical Results: A Case Series.

Introduction: A new device, TresLock (KISCO DIR Co., Ltd., Kobe), has been used for the treatment of unstable proximal femoral fractures and was designed based on Japanese anatomical characteristics. It has three sliding hip screws with one side plate. The angle of all screws relative to the plate has been set to 128°, and each hip screw has a short thread (15 mm) to prevent crossing of the fracture line. In this study, we evaluated the morphological compatibility of TresLock. Methods: We treated 10 patients with hip fractures using TresLock at our institution between September 2016 and December 2017. The average age of the patients was 83.8 years (range, 73-93 years). Fractures included five proximal neck transcervical shear fractures (Orthopaedic Trauma Association [OTA] type-31B2.3, Pauwels III) and five basicervical fractures (OTA type-31B3). The clinical course and three-dimensional computed tomography were evaluated postoperatively. Results: In all cases, all three screws were inserted within the femoral neck. The screws were inserted at an axis of 2.5 ± 1.3° varus to the femoral neck axis. The distance from the subcapital line to the three (proximal-anterior, proximal-posterior, and distal) screw thread ends was 12.0 ± 1.8 mm, 10.4 ± 2.4 mm, and 11.6 ± 4.0 mm, respectively and was sufficient to actuate compression force. However, one case (Pauwels III) required reoperation because of non-union. Conclusion: Careful follow-up is needed, but TresLock shows good anatomical compatibility for femurs among the Japanese population.

Comparison of hip structure analysis and grip strength between femoral neck and basicervical fractures.

BACKGROUND: The purpose of this study was to analyze differences in geometrical properties of the proximal femur and predict the occurrence of basicervical fractures through a comparative study of femoral neck and basicervical fractures in patients undergoing hip structural analysis (HSA). METHODS: All patients with hip fractures who were at least 65 years old and admitted to our hospital between March 2017 and December 2019 were eligible for this study. During the study period, 149 femur neck fractures (FNF) and basicervical fractures (intertrochanteric fractures of A31.2) were included in this study. Fifty-nine patients were included in the final analysis. Factors considered to be important confounders affecting the occurrence of basicervical hip fractures were chosen for propensity-score analysis. A logistic model with basicervical hip fracture as the outcome and age, sex, weight, spinal T-score, hip T-score, and vitamin D levels as confounders was used to estimate the propensity score. RESULTS: The cross-sectional moment of inertia (CSMI) of the intertrochanter was significantly lower in patients with basicervical hip fracture (HF) than in patients with FNF (p = 0.045). However, there was no significant differences in any other HSA variable between the two groups. Receiver operating characteristic (ROC) analysis showed that cutoff point for HSA was 100 for hip axis length (HAL) (AUC = 0.659, p < 0.001) and 5.712 for CSMI of the intertrochanter (AUC = 0.676, p < 0.001). ROC analysis showed that cutoff points of HAL, CSMI of intertrochanter, and handgrip strength were 104.8, 8.75, and 16.9, respectively (AUC = 0.726, p < 0.001). CONCLUSIONS: Proximal femoral geometric analysis using HSA is a useful method for predicting the type of hip fracture. Additionally, a lower CSMI, a shorter HAL, and a lower grip strength are major predictors of basicervical fractures.

Risk Factors Associated with Failure of Cephalomedullary Nail Fixation in the Treatment of Trochanteric Hip Fractures.

BACKGROUND: Intramedullary (IM) nailing is widely performed in elderly patients with trochanteric fractures. Thus, it is important to identify causative factors associated with fixation failure. We investigated fixation failures after IM nailing in elderly patients with trochanteric fractures and compared the failure group with nonfailure group to identify risk factors of fixation failure. METHODS: A total of 396 patients aged 65 years or older underwent IM nailing for trochanteric fractures between January 2012 and August 2016 at our institution. Of those, 194 patients who were followed up for more than 12 months were enrolled in this study; 202 patients were excluded due to death during follow-up, bedridden status before injury, and loss to follow-up. All patients underwent plain radiography and preoperative computed tomography (CT). RESULTS: Fixation failure occurred in 11 patients (5.7%). Seven patients had stable fractures (AO/OTA); eight patients had basicervical fractures (confirmed by CT). Five patients had comminution in the greater trochanter (confirmed by CT). Regarding fracture reduction, eight patients showed discontinuity in the anterior cortex. The position of the lag screw on the lateral view was in the center in six patients and in a posterior area in the other five patients. On the basis of comparison with the 183 patients without fixation failure, risk factors of fixation failure were higher body mass index (BMI; p = 0.003), basicervical type of fracture (p = 0.037), posterior placement of the lag screw on the lateral view (p < 0.001), and inaccurate reduction of the anterior cortex (p = 0.011). CONCLUSIONS: Among the risk factors of fixation failure after IM nailing in elderly patients with trochanteric fractures, discontinuity of the anterior cortex and posterior position of the lag screw are modifiable surgeon factors, whereas higher BMI and basicervical type of fracture are nonmodifiable patient factors. Therefore, care should be taken to avoid fixation failure in IM nailing for patients with a basicervical type of fracture or higher BMI or both.

Risk Factors Associated with Failure of Cephalomedullary Nail Fixation in the Treatment of Trochanteric Hip Fractures

BACKGROUND: Intramedullary (IM) nailing is widely performed in elderly patients with trochanteric fractures. Thus, it is important to identify causative factors associated with fixation failure. We investigated fixation failures after IM nailing in elderly patients with trochanteric fractures and compared the failure group with nonfailure group to identify risk factors of fixation failure.METHODS: A total of 396 patients aged 65 years or older underwent IM nailing for trochanteric fractures between January 2012 and August 2016 at our institution. Of those, 194 patients who were followed up for more than 12 months were enrolled in this study; 202 patients were excluded due to death during follow-up, bedridden status before injury, and loss to follow-up. All patients underwent plain radiography and preoperative computed tomography (CT).RESULTS: Fixation failure occurred in 11 patients (5.7%). Seven patients had stable fractures (AO/OTA); eight patients had basicervical fractures (confirmed by CT). Five patients had comminution in the greater trochanter (confirmed by CT). Regarding fracture reduction, eight patients showed discontinuity in the anterior cortex. The position of the lag screw on the lateral view was in the center in six patients and in a posterior area in the other five patients. On the basis of comparison with the 183 patients without fixation failure, risk factors of fixation failure were higher body mass index (BMI; p = 0.003), basicervical type of fracture (p = 0.037), posterior placement of the lag screw on the lateral view (p < 0.001), and inaccurate reduction of the anterior cortex (p = 0.011).CONCLUSIONS: Among the risk factors of fixation failure after IM nailing in elderly patients with trochanteric fractures, discontinuity of the anterior cortex and posterior position of the lag screw are modifiable surgeon factors, whereas higher BMI and basicervical type of fracture are nonmodifiable patient factors. Therefore, care should be taken to avoid fixation failure in IM nailing for patients with a basicervical type of fracture or higher BMI or both.

Treatment With Helical Blade Cephalomedullary Nail for Two-Part Basicervical Proximal Femoral Fracture in Elderly Patients: A Retrospective Observational Study.

BACKGROUND: Basicervical proximal femoral fracture is a known subtype of extracapsular fracture and is mechanically unstable, especially for the rotational direction, which may lead to implant failure. A cephalomedullary nail (CMN) is widely used for the fixation of unstable extracapsular fracture; however, its application for basicervical fracture remains controversial. Helical blade CMN is proven to have more rotational stability than traditional lag screw implants and potentially advantageous in the treatment of basicervical fracture. The aim of this study is to assess the effectiveness of helical blade CMN for basicervical fracture in elderly patients. METHODS: We conducted a retrospective review of 500 consecutive extracapsular fracture patients treated surgically between January 2005 and February 2015. Patients who had trochanteric extension or multifragment fracture were excluded. Sixteen cases of 2-part basicervical proximal femoral fracture were identified. All patients were treated with the same single helical blade CMN system (DePuy Synthes PFNA-II). Implant-related complications were recorded. RESULTS: Two patients dropped out during follow-up and 14 patients were included in the analysis. The average follow-up period was 21.9 months. No major complication was observed. The patients were subcategorized into 2 groups: nondisplaced (displacement <2 mm at any point of the fracture line) or displaced. Excessive telescoping was observed in 2 patients, both of whom were in the displaced fracture group. The overall implant-related complication rate was 14.2% (2/16). CONCLUSION: Internal fixation with the helical blade CMN system can be considered as a treatment option for 2-part basicervical proximal femoral fracture in elderly patients.

Diagnosis and treatment for the basicervical fractures of the trochanteric region / 北京大学学报(医学版)

Objective:To evaluate the rate of basicervical fractures and document their diagnosis and treatment.Methods: From January 2005 to May 2016,28 basicervical fractures of the 832 trochanteric fractures were collected and evaluated.The patients were treated with multiple screws,dynamic hip screw (DHS),intramedullary nail.Via the operation time,postoperative hospitalization,loss of blood duration the operation,hidden blood loss,total blood loss,mean union time and the final follow-up Harris hip score,the characteristics of different internal fixations were compared and analyzed.Results: The incidence of basicervical fractures was 3.37％ (28/832) in our study.In the intramedullary nail group (16 patients),the operation time was 55 (20,120) min,the postoperative hospitalization was 3(2,7) d,the intraoperative blood loss was 50(5,100) mL,the hidden blood loss was 533.37 (376.19,987.15) mL,and the total blood loss 627.35 (406.19,1037.16) mL.The union time and final follow-up Harris score were 6 (3,9) months and 90.25 (74,100) min.In the DHS group (8 patients),the operation time was 87.5 (65,115) min,the postoperative hospitalization was 5.5 (2,17) d,the intraoperative blood loss was 100 (50,300) mL,the hidden blood loss was 278.11 (202.43,849.97) mL,and the total blood loss 580.19 (368.55,899.97) mL.The union time and final follow-up Harris score were 5.5 (4,12) months and 85.5 (84,87) min.In the multiple screws group (4 patients),the operation time was 47.5 (35,75) min,the postoperative hospitalization was 5 (2,12) d,the intraope-rative blood loss was 20 (2,70) mL,the hidden blood loss was 150 (100.00,412.01) mL,and the total blood loss 195.00 (120.00,414.01) mL.The union time and final follow-up Harris score were 4 (4,6) months and 80 (61,97) min.The patients treated with multiple screws and intramedullary nail had a shorter operation time than the DNS group,but no obvious difference was found between the other two groups (P=0.367).Postoperative hospitalization had no significant difference among the three groups.The intraoperative bleeding was more in the DHS group,the other two groups had no significant difference (P=0.100).However,the hidden blood loss was more in the intramedullary nail group,the other two groups had no significant difference (P=0.134).The total blood loss in the intramedullary nail group was more than multiple screw group,similar to the DHS group (P=0.483).One patient treated with multiple screws underwent internal fixation failure three months after operation.The mean union time and final follow-up Harris scores had no significant difference among the three groups (P>0.05).Conclusion: Through this study,we found that the incidence of basicervical fractures is low.Fractures with no shift can be confirmed by preoperative X-ray.For displaced fractures,preoperative CT + 3D reconstruction is recommended.Surgical treatment by closed reduction and internal fixation with DHS or intramedullary nail is shown to be very effective.