Medial Buttress Research Articles

Biomechanical evaluation of different internal fixation methods based on finite element analysis for Pauwels type III femoral neck fracture

Background and objectiveThe best internal fixation method for the treatment of Pauwels type III femoral neck fractures (FNFs) remains to be demonstrated. Through finite element analysis, this study explored whether dynamic hip screw (DHS) combined with anti rotation screw or medial buttress plate can improve the stability of internal fixation, and the femoral neck system (FNS) with similar structure to DHS and the traditional cannulated screw (CSs) were added for comparison. To evaluate their respective biomechanical advantages and disadvantages in the treatment of Pauwels type III FNFs. MethodsSix groups of internal fixation models for the treatment of FNFs were established, including CSs, DHS, DHS combined with single anti-rotation screw (DHS + SS), and DHS combined with both anti-rotation screw (DHS + BS), DHS combined with medial buttress plate (DHS + MBP), new femoral neck internal fixation system (Femoral Neck System, FNS). Four finite element analysis models were established for each group, evaluation of femoral displacement and internal fixation stress during stair climbing and walking conditions, and the contact force of the hip joint was used in two cases, dynamic and static. ResultsThe fracture plane motion and peak stress of internal fixators were the lowest with DHS + BS and CSs fixation, and the two results are very close, The peak value of DHS combined with anti rotation screw or medial buttress plate is much lower than that of DHS, indicating that the fixation effect of the combined model is enhanced, and there is no significant difference between FNS and DHS + SS. ConclusionBoth the anti rotation screw and medial buttress plate can effectively reduce the movement of fracture section and share the shear force of DHS, FNS has the similar fixation stability to DHS + SS, DHS + BS has the biomechanical advantages of significantly reducing the risk of internal fixation failure and femoral yield. Therefore, the use of DHS + BS may be a more favorable choice in the case of Pauwels type III FNFs with higher fixation requirements.

Finite element analysis of femoral neck system in the treatment of Pauwels type III femoral neck fracture.

The optimal treatment strategy for femoral neck fractures remained controversial, especially the Pauwels type III femoral neck fracture of young patients was a challenge. Femoral neck system (FNS) was a newly developed internal fixation for treating femoral neck fracture and this study aimed to compare the biomechanical advantages and disadvantages between FNS and 3 cannulated configuration screws (CCS) with or without an additional medial buttress plate (MBP). In this study, Pauwels type III femoral neck fracture model with an angle of 70° was constructed and 3 different fixation models, FNS, CCS + MBP, CCS alone, were developed. A vertical force of 2100N was applied on the femoral head, then the maximum von Mises stress of whole model, distal femur, femoral head, and internal fixation was recorded, as well as the stress distribution of whole model, proximal fracture section, and internal fixation of the 3 models. Moreover, the maximum displacement of the whole model, distal femur, femoral head, internal fixation, and the relative displacement of the proximal and distal portion was also compared. The maximum von Mises stress value was 318.302 MPa in FNS, 485.226 MPa in CCS + 1/3 plate, and 425.889 MPa in CCS. The FNS showed lowest maximum von Mises stress values in distal part, femoral head, and internal implant. All fixation configurations were observed stress concentrated at the posteroinferior area of cross-section of femoral head and at the fracture section area of implant; however, FNS had more uniform stress distribution. For displacement, the maximum displacement value was 8.5446 mm in FNS, 8.2863 mm in CCS + 1/3 plate, and 8.3590 mm in CCS. However, FNS had higher maximum displacement in femoral head and internal implant, but lower maximum displacement in the distal part of fracture model. The FNS represented a significantly higher relative displacement between the femoral head and distal femur when compared with the other 2 fixation configurations. The newly developed FNS could achieve the dual effect of angular stability and sliding compression for the treatment of Pauwels type III femoral neck fractures, which provided superior biomechanical stability than CCS alone and CCS with additional MBP.

Comparative finite element analysis of four different internal fixation implants for Pauwels type III femoral neck fractures in various fracture angles in the sagittal plane.

Objectives This study aimed to evaluate the performance of four different fixation techniques for Pauwels type III femoral neck fractures considering the fracture morphology in the sagittal plane.Materials and methods We constructed three different fracture morphologies in the sagittal plane in Pauwels type III femoral neck fractures: posteriorly angled at 20°, neutral, and anteriorly angled at 20°. We set up four fixation devices, including three cannulated screws (3CS), a dynamic hip screw with an antirotational screw (DHS+CS), a proximal femoral locking plate (PFLP), and three cannulated screws with a medial buttress plate (3CS+MBP). The twelve models were created and analyzed using the finite element analysis.Results The finite element analysis revealed that 3CS+MBP yields better results in total vertical and rotational displacements, regardless of the fracture angle in the sagittal plane. For the anterior and posterior angled fractures in the sagittal plane, the PFLP was superior to the DHS+CS. However, the DHS+CS exhibited less displacement than the PFLP in the neutral fracture line in the sagittal plane. The 3CS group demonstrated poor mechanical stability for Pauwels type III fractures.Conclusion Regardless of the fracture line in the sagittal plane, the 3CS+MBP showed better biomechanical behaviors than the 3CS, DHS+CS, and PFLP. In addition, in contrast to the DHS+CS, the PFLP displayed less vertical and rotational displacement in the anterior and posterior fracture lines in the sagittal plane.

Biomechanical comparison of four different fixation methods in the management of Pauwels type III femoral neck fractures: Is there a clear winner?

BackgroundCannulated screws augmented with the medial buttress plate could confer greater biomechanical stability and higher union rates than the screw fixation alone for treating young patients with Pauwels type III femoral neck fractures (FNFs). No study has evaluated the effects of distal bicortical screw fixation and biomechanical properties of buttress plate augmentation under simultaneous vertical and rotational forces, physiologically acting on the hip joint. This study aimed to compare the biomechanical properties of four methods of three cannulated screw fixation under the combined axial and torsional loading in a synthetic femur model of type III FNF. MethodsTwenty-four third-generation composite femora were divided into four groups (6 femora in each group) based on the screw fixation configuration: inverted triangle configuration (Group A), Pauwels' configuration (Group B), inverted triangle configuration combined with medial buttress plate using distal unicortical (Group C), and distal bicortical screw placement (Group D). A Pauwels type III FNF was simulated on the sawbones. Each model was subjected to the combined axial and torsional cyclic loading and subsequently tested to failure. ResultSignificant differences were determined in axial stiffness (AS) among the four groups (p = 0.024), whereas there was no significant difference in torsional stiffness (p = 0.147). The mean AS was higher in group D (639.5 ± 86.2 N/mm) than in group A (430.6 ± 94.8 N/mm), group B (426.2 ± 41.9 N/mm), and group C (451.2 ± 156.7 N/mm). Failure forces (FFs) were significantly different among four groups (p = 0.007), while there was no considerable difference in failure moment values (p = 0.555). The mean FF was significantly higher in group D (1307.1 ± 96.4 N) than in group A (1076.9 ± 371.2 N) and group B (1075.5 ± 348.3 N) (p = 0.014 and p = 0.018, respectively). There was no significant difference in the mean FF between groups D and C. ConclusionRegardless of the medial plate use, multiple cannulated systems could provide similar biomechanical results regarding torsional stiffness and failure moments. Bicortical placement of the most distal screw in medial buttress plate application could improve axial stability but not significantly affect the rotational stability of the inverted triangle screw fixation system in managing type III FNFs.

Preliminary outcomes of the surgical navigation system combined with intraoperative three-dimensional C-arm computed tomography for zygomatico-orbital fracture reconstruction

This study analyzed the outcomes of zygomatico-orbital fracture reconstruction using the real-time navigation system with intraoperative three-dimensional (3D) C-arm computed tomography (CT). Fifteen patients with zygomatico-orbital or isolated orbital/zygoma fractures were enrolled in this prospective cohort. For zygoma reduction, the displacement at five key sutures and the differences between preoperative and intraoperative CT images were compared. For orbital reconstruction, the bilateral orbital volume differences in the anterior, middle, and posterior angles over the medial transitional buttress were measured. Two patients required implant adjustment once after the intraoperative 3D C-arm assessment. On comparing the preoperative and postoperative findings for the zygoma, the average sum of displacement was 19.48 (range, 5.1–34.65) vs. 1.96 (0–3.95) mm (P < 0.001) and the deviation index was 13.56 (10–24.35) vs. 2.44 (0.6–4.85) (P < 0.001). For the orbit, the mean preoperative to postoperative bilateral orbital volume difference was 3.93 (0.35–10.95) vs. 1.05 (0.12–3.61) mm3 (P < 0.001). The mean difference in the bilateral angles at the transition buttress was significantly decreased postoperatively at the middle and posterior one-third. There was no significant difference in orbital volume, angle of the transition zone, and the sum of five zygoma distances between post operative results and preoperative virtual planning. The surgical navigation system with the intraoperative 3D C-arm can effectively improve the accuracy of zygomatico-orbital fracture reconstruction and decrease implant adjustment times.

Medial Buttress Plate and Allograft Bone-Assisted Cannulated Screw Fixation for Unstable Femoral Neck Fracture with Posteromedial Comminution: A Retrospective Controlled Study.

ObjectiveTo investigate the outcomes of open reduction and internal fixation combined with medial buttress plate (MBP) and allograft bone‐assisted cannulated screw (CS) fixation for patients with unstable femoral neck fracture with comminuted posteromedial cortex.MethodsIn a retrospective study of patients operated on for unstable femoral neck fractures with comminuted posteromedial cortex from March 2016 to August 2020, the clinical and radiographic outcomes of 48 patients treated with CS + MBP were compared with the outcomes of 54 patients treated with CS only. All patients in the CS + MBP group were fixed by three CS and MBP (one‐third tubular plates or reconstructive plates) with bone allografts. The surgery‐related outcomes and complications were evaluated, including operative time, blood loss, union time, femoral head necrosis, femoral neck shortening, and other complications after the operation. The Harris score was evaluated at 12 months after the operation.ResultsAll patients were followed up for 12–40 months. The average age of patients in the CS‐only group (54 cases, 22 females) and CS + MBP group (48 cases, 20 females) was 48.46 ± 7.26 and 48.73 ± 6.38 years, respectively. More intraoperative blood loss was observed in the CS + MBP group than that of patients in CS‐only group (153.45 ± 64.27 vs 21.86 ± 18.19 ml, t = 4.058, P = 0.015). The average operative time for patients in the CS + MBP group (75.35 ± 27.67 min) was almost double than that of patients in the CS‐only group (36.87 ± 15.39 min) (t = 2.455, P < 0.001). The Garden alignment index of patients treated by CS + MBP from type I to type IV was 79%, 19%, 2%, and 0%, respectively. On the contrary, they were 31%, 43%, 24% and 2% for those in the CS‐only group, respectively. The average healing times for the CS‐only and CS + MBP groups were 4.34 ± 1.46 and 3.65 ± 1.85 months (t = 1.650, P = 0.102), respectively. Femoral neck shortening was better in the CS + MBP group (1.40 ± 1.73 mm, 9/19) than that in the CS‐only group (4.33 ± 3.32 mm, 24/44). Significantly higher hip function was found in the CS + MBP group (85.60 ± 4.36 vs 82.47 ± 6.33, t = 1.899, P = 0.06). There was no statistical difference between femoral head necrosis (4% vs 11%, χ 2 = 1.695, P = 0.193) and nonunion (6% vs 9%, χ 2 = 0.318, P = 0.719).ConclusionFor unstable femoral neck fractures with comminuted posteromedial cortex, additional MBP combined with bone allografts showed better reduction quality and neck length control than CS fixation only, with longer operative time and more blood loss.

Effectiveness analysis of medial buttress plate augmented hollow lag screws fixation in combination with sartorius pedicled iliac flap for the treatment of femoral neck fractures in young adults

To evaluate the effectiveness of medial buttress plate augmented hollow lag screws fixation in combination with sartorius pedicled iliac flap for the treatment of femoral neck fractures in young adults. The clinical data of 11 young adult patients with femoral neck fractures between February 2013 and February 2019 were analyzed retrospectively. There were 7 males and 4 females with a mean age of 45 years (range, 32-58 years). Fractures were caused by falling from height in 6 cases, by traffic accident in 4 cases, and by sports injury in 1 case. There were 7 cases in the left hip and 4 cases in the right hip. The mean Pauwels angle was 64° (range, 55°-75°). All patients were treated by medial buttress plate augmented hollow lag screws fixation and sartorius pedicled iliac flap. The X-ray film of pelvis, lateral X-ray film of hip joint, CT scan and three-dimensional reconstruction of hip joint were taken after operation to assess fracture healing and position of the internal fixators. The postoperative hip function was evaluated according to the Harris score. All the incisions healed by first intention, and no complication such as incision infection and lateral femoral cutaneous nerve injury happened. Re-examination on the second day after operation showed that reduction and fixation of fractures was good. All patients were followed up 18-36 months (mean, 29 months). All fractures achieved bony union. The time of bony union was 16-23 weeks, with an average of 18.2 weeks. One patient (9.1%) got osteonecrosis of the femoral head (ONFH) at 30 months after operation. At last follow-up, Harris score was used to evaluate hip joint function, 9 cases were excellent, 1 case was good, 1 case was fair, and the excellent and good rate was 90.9%. Medial buttress plate augmented hollow lag screws fixation in combination with sartorius pedicled iliac flap for the treatment of femoral neck fractures in young adults has the advantage of strong biomechanical stability and can effectively improve the blood supply of femoral head and neck, which subsequently reduce the incidence of ONFH. However, the surgical indication should be fully considered.

The role of the medial buttress plate in the treatment of Pauwels type II and III femoral neck fracture in nonelderly patients: a retrospective study and preliminary results

BackgroundThe purpose of this study was to compare the effectiveness of multiple cannulated screws combined with medial buttress plate or not for the treatment of unstable femoral neck fracture in nonelderly patients.MethodsSixty-nine nonelderly patients with Garden type III-IV femoral neck fracture were retrospectively analyzed. The patients were divided into MCS (multiple cannulated screws) group and CMBP (combined with medial buttress plate) group according to the surgical method. Patient’s demographic data, Harris Hip Score, EQ-5D index and complications at a minimum of 2 years follow-up were analyzed.ResultsThere were 47 patients in the MCS group (35 male and 12 females) with a mean age of 40.28 ± 12.64 years, whereas 22 patients in the CMBP group (17 male and 5 females) with a mean age of 43.86 ± 12.55 years. In the MCS group, there were 1 (2.1%) avascular necrosis, 5 (10.6%) postoperative nonunion, 5 (10.6%) implant failure, and 2 (4.3%) femoral neck shortening. While 1 (4.5%) implant failure, 2 (9.1%) postoperative nonunion and 2 (9.1%) impingement in the CMBP group. For patients with Pauwels type II and III femoral neck fracture, the CMBP group had higher HHS scores at 3 months after surgery than the MCS group (P < 0.05), whereas there was no statistical significance at 6 months, 1 year, and 2 years (P > 0.05). The same results were found in the EQ-5D index.ConclusionsIn our cohort, we observed better outcomes in the CMBP group at 3 and 6 months, with later results similar between groups. However, there were fewer complications in the CMBP group, without obviously blood-supply disruption, especially in Pauwels type II and III. Further, anatomic reduction and stable fixation may contribute to satisfactory outcomes in the treatment of nonelderly displaced femoral neck fractures.

Modified use of the proximal humeral internal locking system (PHILOS) plate for distal femoral nonunions

PurposeNonunion is a common complication after a distal femoral fracture (DFF). Standard treatment consists of revision plating and/or bone grafting. Single lateral plating for a distal femoral nonunion can be insufficient in case of a persistent medial gap and compromised bone stock. Alternatively, dual plating can be used to treat a distal femoral nonunion, but to date there is no Gold standard. The aim of our study was to report our results after use of a minimally invasively placed proximal humeral internal locking system (Philos) plate as a medial buttress in the treatment of a distal femoral nonunion.MethodsFifteen adult patients with a distal femoral nonunion were prospectively entered in a trauma database and retrospectively assessed. All patients underwent a similar operation, which included removal of failed hardware, nonunion debridement, fixation with a lateral plate, and a medial Philos plate combined with bone grafting. Data collected included union rate, time to union, complications and functional outcome.ResultsIn twelve out of fifteen patients (80%), the fracture united after our index operation. Median time to union was 4.8 months (range 1.6–15). Three patients (20%) needed additional bone grafting surgery. One patient underwent a Judet quadricepsplasty.ConclusionThis study suggests that the Philos plate is a safe and effective adjunct as a medial buttress plate for distal femoral nonunions.

Biomechanical analysis of two medial buttress plate fixation methods to treat Pauwels type III femoral neck fractures

BackgroundFemoral neck fractures in young people are usually Pauwels Type III fractures. The common treatment method are multiple parallel cannulated screws or dynamic hip screw sliding compression fixation. Due to the huge shear stress, the rate of complications such as femoral head necrosis and nonunion is still high after treatment. The aim of our study was to compare the stabilities of two fixation methods in fixating pauwels type III femoral neck fractures.MethodsAll biomimetic fracture samples are fixed with three cannulated screws combined with a medial buttress plate. There were two fixation groups for the buttress plate and proximal fracture fragment: Group A, long screw (40 mm); Group B, short screw (6 mm). Samples were subjected to electrical strain measurement under a load of 500 N, axial stiffness was measured, and then the samples were axially loaded until failure. More than 5 mm of displacement or synthetic bone fracture was considered as construct failure.ResultsThere were no significant differences in failure load (P = 0.669), stiffness (P = 0.842), or strain distribution (P > 0.05) between the two groups.ConclusionsUnicortical short screws can provide the same stability as long screws for Pauwels Type III Femoral Neck Fractures.

Comparison of fibula strut and calcium phosphate cement augmentation of the medial buttress in 2-part proximal humerus fractures reconstruction: a biomechanical study.

Augmentation strategies for surgical fixation of proximal humerus fractures (PHF) are available to address their relatively high failure rate. The purpose of this study was to compare two medial-buttress augmentation strategies for PHF fixation. A two-part PHF model with loss of medial buttress was created in 16 synthetic bones. The PHFs were fixed with locking plates and either calcium phosphate cement (CPC) or fibula strut (FS) augmentation. After cadaveric validations, the fixation constructs were subjected to nondestructive axial compression tests, followed by a cyclic test. Construct stiffness and angular displacement of the humerus head were recorded. Humeral head angular displacement was statistically greater in the CPC group than in the FS group at the applied force of 300N and higher (p <0.05). Axial stiffness was statistically greater in the FS fixation group than in the CPC group at initial and final phases of cyclic loading protocol (p <0.05). In an osteoporotic cadaveric model of a 2-part PHF with loss of a medial buttress, locked plate constructs augmented with FS have a higher resistance to varus collapse compared to those augmented with CPC.

Biomechanical study of two alternative methods for the treatment of vertical femoral neck fractures – A finite element analysis

BackgroundNo consensus has been reached for the treatment of vertical femoral neck fractures (vFNFs). Recently, two alternative methods were invented to treat vFNFs, one of which is a new plate with a sliding groove, which was designed as a substitution of the medial buttress locking plate to combine with cannulated compression screws (CCS) for reducing the breakage possibility of the proximal locking screw during the bone healing. Another one is the femoral neck system (FNS), which was believed with biomechanical superiority. This study aims to compare the biomechanics of these two new implants with three previous methods via finite element analysis (FEA) to validate whether they are suitable for the treatment of vFNFs. MethodsFive 70-degree Pauwels type III transcervical FNFs (vFNFs, AO/OTA 31B2.3r) models were built and fixed by CCS augmented with the newly designed sliding groove buttress plate (CCS+BS) and FNS. For comparison, models fixed by three parallel cannulated compression screws (CCS), biplane double-supported screw fixation (BDSF), CCS augmented with a medial buttress locking plate (CCS+BL) were also built. A 2100N load was applied along with the mechanical axis. Parameters of the maximal stress as well as the maximal displacement of the implants and bone, the maximal relative displacement of interfragments, and the stiffness, were analyzed to compare the biomechanical characteristics of the five models. ResultsCCS+BS and CCS+BL showed stronger fixation strength with improved stiffness (1012.05N/mm, 1092.04N/mm), reduced maximal displacement of the implants (1.976mm, 1.838mm) and bone (2.075mm, 1.923mm), when compared with CCS (925.11N/mm, 2.158mm and 2.270mm) and BDSF (842.36N/mm, 2.299mm and 2.493mm). While FNS showed the weakest stiffness (593.22N/mm) and largest maximal displacement of the implants (3.234mm) and bone (3.540mm) among the five models. ConclusionsCCS+BS has a better biomechanical performance than CCS and BDSF, which offers a new choice to deal with vFNFs. The construction stability of FNS is weaker than CCS, BDSF, and CCS+BL, indicating that this method may not as stable as reported in the previous study.

Factors Associated with Femoral Neck Shortening After Closed or Open Reduction and Screw Fixation.

This study aimed to evaluate the incidence of femoral neck shortening (FNS) after the treatment of displaced and non-displaced femoral neck fractures with closed or open reduction internal fixation, and determine the independent factors associated with this condition. The study included 81 patients who underwent internal fixation by closed or open reduction with multiple screws between 2013 and 2018 due to femoral neck fracture (FNF) and were followed up for at least 1year. Patients were divided into two groups as with and without FNS. The patient, fracture, and surgical parameters compared between the two groups, and the factors affecting development of FNS were investigated. Internal fixation was applied by closed reduction in 56 patients (69.1%) and open in 25 (30.9%). FNS was detected in 41 patients (50.6%), with the mean shortening 6.3 ± 6.4mm. Fracture union achieved in 72 patients (89%). The mean time to fracture union was 4.3 ± 2.3months.No statistically significant relationship found between FNS and the parameters of gender, age, smoking, reduction type, number, type and orientation of screws, Singh index, and Garden fix index (p > 0.05).However, there was significant difference between two groups regarding energy of the fracture, fragmentation, coronal angulation, Garden type, and fixation with medial buttress plate (p < 0.05). FNS is an expected condition in FNF fixed by screws. Patients with high-energy traumas and advanced Garden types are more likely to have FNS. The use of medial plate may be effective in preventing FNS.

The Role of Medial Buttress Plate Augmentation of Cannulated Screws in Unstable Femoral Neck Fractures: A Pilot Study

Background: About 20% of femoral neck fracture surgeries require re-operation. The use of medial buttress plate may reduce the reoperation rate. The purpose of this study is to examine the results of using the method of augmentation of the cannulated screws with medial buttress plate for treatment of unstable femoral neck fractures. Methods: This study included patients with femoral neck fractures of Pauwels type 2 and 3 in which closed reduction was not successful. The patients underwent open anatomical reduction and implantation of three screws, and then the medial placement of the buttress plate was performed. Patients were followed up after 2 weeks, 6 weeks, 3 months, and 6 months. Union and fracture healing and operative complications were assessed using plain radiography. Results: This study included 8 patients with Pauwels type 2 and 3 femoral neck fractures. All patients were men with the mean age of 38.0 ± 11.3 years. Re-hospitalization 30 days after surgery, surgical site infection, deep vein thrombosis (DVT), and deep infection were not observed in any of the patients. The angle between the neck and the femur shaft dramatically increased during the 6-month follow-up (P = 0.049). Union occurred in 6 (75%) patients after 6 months, while 2 patients were lost to follow up. Participants’ Harris Hip Score (HHS) had a significant improvement from 3 months to 6 months after surgery (P = 0.02). Conclusion: Augmentation of cannulated screws with medial buttress plate for unstable femoral neck fractures in patients has advantages in short-term clinical follow-up.

Reporting on quality of reduction and fixation of intertrochanteric fractures-A systematic review.

Patient outcomes after intertrochanteric fracture fixation is the subject of a large body of published and ongoing clinical research. Fracture reduction and stable fixation are a pre-requisite for achieving optimal results. However, reporting on the quality of postoperative reduction and fixation, has been inconsistent in the literature on intertrochanteric fractures. The purpose of this study was to examine the quality and consistency of reporting of immediate postoperative reduction and fixation in clinical outcome studies of intertrochanteric fracture fixation. Outcome studies of intertrochanteric fractures, published between 2001 and 2019, were identified using a PubMed. Six journals were identified as having a high impact on intertrochanteric fracture research by either having an impact factor greater than 3.0 or more than 30 published studies fulfilling inclusion criteria. Two independent reviewers reviewed each article for its reporting on immediate post-operative radiographic findings and whether an attempt was made to correlate these findings to outcomes. Quality and consistency of reduction reporting were assessed by recording the type and number of uniquely reported reduction metrics in all of the included studies. The reviewers identified 134 papers for the study, of which 110 (82%) reported on immediate postoperative radiographic findings. Of the papers reporting these findings, 84 (76%) reported quantitative measurements. Quantitative reporting changed from 79% in papers published between 2001-2014 to 86% in papers published between 2015-2019. Sixty-one (46%) papers reported Tip-Apex Distance, 56 (42%) reported degree of varus (compared to non-injured side), 42 (31%) reported Neck-Shaft Angle restoration, 31(23%) reported leg-length discrepancy, 18 (13%) reported rotation, 15(11%) reported on the status of the lateral wall, and 6 (4%) reported on calcar (medial buttress) reduction. Sixty-eight (51%) papers that measured reduction found an association between better immediate post-operative reduction and improved outcomes. Despite its recognized influence on outcomes of intertrochanteric fractures, leading peer-reviewed journals do not uniformly report on the immediate postoperative assessment of the quality of reduction and fixation. However, reporting has improved over the past five years. Standardized quantitative metrics will need to be reported in the future to allow meaningful comparisons between studies and accurate assessment of intertrochanteric fracture outcome.

Research progress of medial buttress plate assisted fixation for femoral neck fractures in young adults

To summarize the research progress of medial buttress plate assisted fixation for femoral neck fractures in young adults. The literature about buttress plate assisted fixation for femoral neck fractures in young adults was widely reviewed and analyzed. The design principle, background, biomechanical characteristics, and clinical results of buttress plate were summarized. Medial buttress plate assisted fixation is the latest treatment of femoral neck fractures in young adults, which can convert the shear force at the fracture sides into compression force and promote fracture healing. Medial buttress plate can improve the biomechanical stability of femoral neck fractures and reduce the maximum stress of fixation implants. In clinical, the medial buttress plate can maintain fracture reduction, reduce the incidences of nonunion and surgical failure, and improve hip joint function. Medial buttress plate assisted fixation can achieve good effectiveness for femoral neck fractures in young adults. However, due to the preliminary application, its indications, fixation implants, and long-term effectiveness need to be further studied and improved.

Biomechanical evaluation of internal fixation implants for femoral neck fractures: A comparative finite element analysis

Background and ObjectiveIt remains controversial regarding the optimal type of fixation implant for the treatment of femoral neck fractures (FNFs). Biomechanical rational for implant choices can benefit from the integration of finite element analysis (FEA) in device evaluation and design improvement. In this study, we aim to evaluate biomechanical performance of several internal fixation implants for Pauwels type III FNFs under physiological loading conditions using FEA, as well as to assess the biomechanical contribution of medial buttress plate (MBP) augmentation. MethodsSeveral fixation styles for FNFs have been analyzed numerically by the finite element method. Five groups of models were developed with different FNFs fixation implants, including dynamic hip screw (DHS), cannulated screws (CSs), proximal femoral nail antirotation (PFNA), DHS with MBP augmentation (DHS+MBP), and CSs with MBP (CSs+MBP). For each group, four FE models were established to evaluate strain in bone and stress in devices during walking and stair climbing conditions, which simulated the hip contact force using static and dynamic loadings respectively. ResultsNo notable differences were observed in peak strain within implanted bone and maximum stress values of the device between DHS and CSs. The implanted femur with PFNA was in a lower state of bone strain and implant stress. Although the buttress plate did not decrease peak bone strain, it alleviated stress concentration on device, especially for CSs under dynamic loadings. ConclusionsCompared to the other fixation styles, the PFNA showed biomechanical advantages of decreasing risk of implant failure and bone yielding. The MBP augmentation provided an additional load path to bridge fracture fragments, which reduced failure risk of DHS and CSs, especially during dynamic loading scenarios. Although further studies are needed for patients with other types of FNFs, our findings may provide valuable references for device design optimization in terms of complex physiological loadings, as well as for clinical decision making in surgical treatment of FNFs.

Dynamic limited axial compression yields favorable functional outcomes in the fixation of Pauwels type-3 femoral neck fractures: A retrospective cohort study

PurposePauwels type-3 femoral neck fractures are challenging injuries to manage with high rates of complications after internal fixation and no consensus has been reached regarding the optimal fixation construct. The current study aims to evaluate the effect of dynamic limited axial compression in parallel screws combined with medial buttress plate (SMBP) or lateral compression plate (LCP) fixation of Pauwels type-3 femoral neck fractures. MethodsWe performed a retrospective analysis of 51 cases of Pauwels type-3 femoral neck fractures who were fixed by SMBP or LCP. Specifically, the screw fixing the femoral head in the buttress plate was omitted. Postoperative complications and functional outcomes were mainly studied. ResultsWith a mean follow-up of 19.9 months, the rate of neck shortening was higher in the LCP group than that in SMBP group (32.1% vs. 8.7%, p = 0.04). Neither nonunion nor avascular necrosis was observed in both groups. Good-to-excellent Harris hip score accounts for 95.2% in SMBP group and 89.3% in LCP group (p = 0.40). Moreover, older age, fracture comminution and compression plate fixation predispose to neck shortening. ConclusionDynamic limited axial compression by SMBP or LCP fixation was effective to improve the functional outcome of patients with Pauwels type-3 femoral neck fractures.

Medial Buttress Plating for Humerus Fractures With Unstable Medial Column.

The purpose of this study was to report surgical tips and techniques on the use of additional medial buttress plate fixation in proximal humeral fractures with unstable medial column restoration after lateral locking compression plate fixation. Between April 2011 and January 2017, 17 patients with medial cortical deficiency were treated using this technique. The average follow-up period was 30 (range, 12-81) months. Successful fracture healing was achieved in all 17 cases. The mean neck-shaft angle change was 1.33 degree (range, 0-7.4 degree). Anterior glenoid rim erosion occurred in 1 patient. No avascular necrosis of the humeral head or significant loss of reduction, and no implant failure or screw perforation occurred. In the first part of this study, we described in detail the indications and surgical technique applied to these fractures. In the second part, we reviewed the clinical and radiographic outcomes of these patients. Supplemental medial buttress plate fixation after lateral locking compression plate fixation was effective in preventing varus collapse and implant failure for proximal humeral fractures with an unstable medial column.

Medial anatomical buttress plate in treating displaced femoral neck fracture a finite element analysis

BackgroundDisplaced femoral neck fractures in young adults are most likely to result from high energy trauma that causes a vertically-oriented shearing injury through the femoral neck. The optimal strategy for treatment of displaced femoral neck fractures remains an unsolved challenge in orthopedic surgery. Methodsour group has previously designed a medial anatomical buttress plate (MABP) based on the analysis of the computed tomography (CT) data of anatomical structures derived from a large sample population. In this study, finite element analyses (FEA) were carried out to compare the outcomes of the combination of our MABP with cannulated screws to those of the combination of tubular plate with cannulated screws, and to those of using cannulated screws alone. ResultsMABP resulted in a more stable fixation as compared to the other two approaches, with respect to the femur and the stress distributions, stress peaks, and Z axis displacements. ConclusionsThe FEA encouraged us that addition of a medial buttress plate not only achieved superior medial buttress stability but also achieves superior performance because it perfectly fits with the existing anatomic structure of medial femoral neck. The results from our study may provide references for clinical decision making in dealing with such patients.