The vertical hip fracture - a treatment challenge. A cohort study with an up to 9 year follow-up of 137 consecutive hips treated with sliding hip screw and antirotation screw

Biomechanical study of a biplanar double support screw (BDSF) technique based on Pauwels angle in femoral neck fractures: finite element analysis

Objective

The objective of the present study is to conduct a comparative analysis of the biomechanical advantages and disadvantages associated with a biplanar double support screw (BDSF) internal fixation device.

Methods

Two distinct femoral neck fracture models, one with a 30° angle and the other with a 70° angle, were created using a verified and effective finite element model. Accordingly, a total of eight groups of finite element models were utilized, each implanted with different configurations of fixation devices, including distal screw 150° BDSF, distal screw 165° BDSF, 3 CLS arranged in an inverted triangle configuration, and 4 CLS arranged in a "α" configuration. Subsequently, the displacement and distribution of Von Mises stress (VMS) in the femur and internal fixation device were assessed in each fracture group under an axial load of 2100 N.

Results

At Pauwels 30° Angle, the femur with a 150°-BDSF orientation exhibited a maximum displacement of 3.17 mm, while the femur with a 165°-BDSF orientation displayed a maximum displacement of 3.13 mm. When compared with the femoral neck fracture model characterized by a Pauwels Angle of 70°, the shear force observed in the 70° model was significantly higher than that in the 30° model. Conversely, the stability of the 30° model was significantly superior to that of the 70° model. Furthermore, in the 70° model, the BDSF group exhibited a maximum femur displacement that was lower than both the 3CCS (3.46 mm) and 4CCS (3.43 mm) thresholds.

Conclusion

The biomechanical properties of the BDSF internal fixation device are superior to the other two hollow screw internal fixation devices. Correspondingly, superior biomechanical outcomes can be achieved through the implementation of distal screw insertion at an angle of 165°. Thus, the BDSF internal fixation technique can be considered as a viable closed reduction internal fixation technique for managing femoral neck fractures at varying Pauwels angles.

Comparison of the Surgical Outcome between the Multiple Screw Fixation and Fixed Angle Devices for the Basicervical Femoral Neck Fractures

Introduction: Basicervical femoral neck fracture (FNF) is an uncommon type of femoral neck fracture and is associated with an increased risk of fixation failure due to its inherent instability. The purpose of this study was to compare the surgical parameters and reoperation rate between the use of a multiple cannulated screw (MCS) and fixed angle device (FAD) in treating basicervical FNFs. Methods: We retrospectively reviewed the records of 885 patients who underwent internal fixation between May 2004 and August 2019 to determine basicervical FNF with at least 12 months of follow-up. Among the identified 77 patients with basicervical FNF, 17 patients who underwent multiple cannulated screw (MCS) fixation and 36 patients who underwent fixed angle device (FAD) fixation were included. We compared the rates of fracture-site collapse and reoperations according to the fixation device. Results: Among the 53 patients with basicervical FNF, 13 patients (24.5%) sustained surgical complications (8 collapses of fracture site and 5 reoperations). The reoperation rate in the MCS group was significantly higher than that in the FAD group (23.5% vs. 2.8%, p = 0.016), without any significant difference in the collapse of the fracture site (11.8% vs. 16.7%, p = 0.642). Conclusions: Although basicervical FNF was rare among hip fractures, fracture site collapse was prevalent and prone to fixation failure. Surgeons should keep this in mind, and consider FAD for basicervical FNF.

The novel magnesium-titanium hybrid cannulated screws for the treatment of vertical femoral neck fractures: Biomechanical evaluation

Background

Conventional cannulated screws are commonly used for internal fixation in the treatment of vertical femoral neck fractures. However, the noticeably high rates of undesirable outcomes such as nonunion, malunion, avascular necrosis, and fixation failure still troubled the patients and surgeons. It is urgent to develop new cannulated screws to improve the above clinical problems. The purpose of this study was to design a novel magnesium-titanium hybrid cannulated screw and to further evaluate its biomechanical performance for the treatment of vertical femoral neck fractures.

Methods

A novel magnesium-titanium hybrid cannulated screw was designed, and the conventional titanium cannulated screw was also modeled. The finite element models for vertical femoral neck fractures with magnesium-titanium hybrid cannulated screws and conventional cannulated screws were respectively established. The hip joint contact force during walking gait calculated by a subject-specific musculoskeletal multibody dynamics model, was used as loads and boundary conditions for both finite element models. The stress and displacement distributions of the cannulated screws and the femur, the micromotion of the fracture surfaces of the femoral neck, and the overall stiffness were calculated and analyzed using finite element models. The biomechanical performance of the Magnesium-Titanium hybrid cannulated screws was evaluated.

Results

The maximum stresses of the magnesium-titanium hybrid cannulated screws and the conventional cannulated screws were 451.5 ​MPa and 476.8 ​MPa, respectively. The maximum stresses of the femur with the above different cannulated screws were 140.3 ​MPa and 164.8 ​MPa, respectively. The maximum displacement of the femur with the hybrid cannulated screws was 6.260 ​mm, lower than the femur with the conventional cannulated screws, which was 7.125 ​mm. The tangential micromotions in the two orthogonal directions at the fracture surface of the femoral neck with the magnesium-titanium hybrid cannulated screws were comparable to those with the conventional cannulated screws. The overall stiffness of the magnesium-titanium hybrid cannulated screw system was 490.17 ​N/mm, higher than that of the conventional cannulated screw system, which was 433.92 ​N/mm.

Conclusion

The magnesium-titanium hybrid cannulated screw had superior mechanical strength and fixation stability for the treatment of the vertical femoral neck fractures, compared with those of the conventional cannulated screw, indicating that the magnesium-titanium hybrid cannulated screw has great potential as a new fixation strategy in future clinical applications.The translational potential of this article: This study highlights an innovative design of the magnesium-titanium hybrid cannulated screw for the treatment of vertical femoral neck fractures. The novel magnesium-titanium hybrid cannulated screw not only to provide sufficient mechanical strength and fixation stability but also to contribute to the promotion of fracture healing, which could provide a better treatment for the vertical femoral neck fractures, beneficially reducing the incidence of nonunion and reoperation rates.

Femoral neck system vs. cannulated screws on treating femoral neck fracture: a meta-analysis and system review

Objective

This meta-analysis aimed to compare the relative safety and efficacy of cannulated compression screw (CCS) and femoral neck system (FNS) in treating patients with femoral neck fractures and to provide evidence-based medical evidence for FNS in treating femoral neck fractures.

Methods

PubMed, Embase, Cochrane, and China National Knowledge Infrastructure databases were searched to collect outcomes related to femoral neck fractures treated with FNS and CCS, including time to fracture healing, incidence of non-union, incidence of osteonecrosis of the femoral head, incidence of failure of internal fixation, rate of femoral neck shortening, Harris hip score, Barthel index, operative time, intraoperative blood loss, fluoroscopy frequency, and complications. A meta-analysis was performed using RevManv5.4 (The Cochrane Collaboration) and Stata v14.0 software.

Results

This analysis included 21 studies involving 1,347 patients. The results showed that FNS was superior to CCS in terms of fracture healing time [mean difference (MD) = -0.75, 95% CI = (-1.04, -0.46), P < 0.05], incidence of bone non-union [odds ratio (OR) = 0.53, 95% CI = (0.29, 0.98), P = 0.04], incidence of osteonecrosis of the femoral head [OR = 0.49, 95% CI = (0.28, 0.86), P = 0.01], incidence of internal fixation failure [OR = 0.30, 95% CI = (0.18, 0.52), P < 0.05], rate of femoral neck shortening [OR = 0.38, 95% CI = (0.27, 0.54), P > 0.05], Harris hip score [MD = 3.31, 95% CI = (1.99, 4.63), P < 0.001], Barthel index [MD =  4.31, 95% CI = (3.02, 5.61), P < 0.05], intraoperative bleeding [MD = 14.72, 95% CI = (8.52, 20.92), P < 0.05], fluoroscopy frequency [OR = 0.53, 95% CI = (0.29, 0.98), P = 0.04], and complications [OR = 0.31, 95% CI = (0.22, 0.45), P < 0.05]. The difference between FNS and CCS in operative time was not statistically significant [MD = -2.41, 95% CI = (-6.88, 2.05), P = 0.29].

Conclusion

FNS treatment of femoral neck fracture can shorten the fracture healing time; reduce the incidence and translucent rate of bone non-union, osteonecrosis of the femoral head, and internal fixation failure; reduce intraoperative blood loss and postoperative complications; and improve hip joint function and activity. We are confident in the findings that FNS, an effective and safe procedure for internal fixation of femoral neck fractures, is superior to CCS.

Novel screw fixation placement configuration for the treatment of Pauwels type III femoral neck fractures: a finite element analysis

Verticality of transcervical hip fractures in young patients is usually connected with typically high-energy fractures which are known as Pauwels type III. Artificial femoral head replacement surgery is mostly not considered for treating femoral neck fractures in such patients. The commonly used devices for the fixation of vertical femoral neck fractures are multiple screws or a sliding hip screw with or without an antirotation screw. Size, location and length of the screws are the most effective parameters in terms of the structural performance of internal fixation implants, but the optimal configuration of the screws is necessary to be investigated to direct the clinical practice. The aim of this study is to compare the biomechanical stability of the standard inverted triangle configuration with the various newly proposed x-crossed screw configurations. FEA simulations carried out in this study demonstrated that using an x-crossed-right assembly in treating Pauwels type III femoral neck fractures satisfies the biomechanical stability in terms of maximum von Mises stresses and maximum femoral head displacement. However, in terms of maximum relative neck fracture displacement, the x-crossed-right assembly would not entirely suffice the desired biomechanical stability. Therefore, using an x-crossed screw assembly in treating femoral neck fractures would provide the needed biomechanical stability.

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

BACKGROUND AND OBJECTIVE

The 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.

METHODS

Six 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.

RESULTS

The 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.

CONCLUSION

Both 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.

New Prognostic Factors in Operated Extracapsular Hip Fractures: Infection and GammaTScore

There is no universal postoperative classification of extracapsular hip fractures (ECFs). We wondered if infection (according to infection after fracture fixation criteria (IAFF)), immediate partial weight bearing (PWB) and/or the new GammaTScore tool could predict early cut-out. We also examined the correlation between GammaTScore and time to consolidation and studied long-term survival. This was a retrospective cohort study of low-energy complete ECFs operated with Gamma3T nailing in 2014 and fully monitoring, in patients aged over 65. Ten not distally locked cases, one late cut-out, one cut-through, one osteonecrosis and one pseudarthrosis were discarded. Patients were classified into early cut-out (7/204; 3.55%) and no early cut-out (197/204; 96.45%). There was a lower percentage of A2 fractures according to the AO Foundation/Orthopaedic Trauma Association classification (AO/OTA, 1997) in early cut-out. IAFF and only the GammaTScore reduction parameter were different for early cut-out, in opposition to immediate PWB, tip-to-apex distance (TAD) or the Baumgaertner-Fogagnolo classification. GammaTScore inversely correlated with consolidation (p < 0.01). Long-term survival time was not statistically significantly lower in the early cut-out group. Small sample of cases may limit our results. Apart from an important role of IAFF, GammaTScore would be useful for predicting consolidation, avoiding complications and reducing costs. Further studies are needed for reliability.

Clinical and Biomechanical Effects of Femoral Neck Buttress Plate used for Vertical Femoral Neck Fractures

PURPOSE

To investigate both the biomechanical and clinical effect of an inferomedial femoral neck buttress plate (FNBP) used to augment a sliding hip screw (SHS) and anti-rotational screw (ARS) in the treatment of traumatic vertical femoral neck fractures.

METHODS

Part 1: Clinical - Retrospective review of patients under age 65 treated with open reduction of a vertical femoral neck fracture. Patients were divided into two groups: Group 1 patients (18 patients) had SHS/ARS fixation augmented with a FNBP, while Group 2 patients (18 patients) had SHS/ARS fixation alone and were matched for age and sex. Demographic data, OTA fracture classification, immediate post-operative and follow-up radiographs were analyzed for quality of reduction, femoral neck shortening (FNS), neck-shaft angle (NSA), avascular necrosis (AVN) and union. Part 2: Biomechanical - Pauwels III femoral neck osteotomy was created in five pairs of cadaveric specimens, then each fracture was reduced and stabilized with a SHS/ARS construct. Specimens were matched and split into Groups 1 and 2, similar to Part 1. Cadaveric specimens were axially loaded in cyclical fashion to analyze for construct stiffness, fracture displacement femoral neck shortening and changes in the neck shaft angle.

RESULTS

Part 1: There were 18 matched patients (14 males and 4 females) in both Group 1 and Group 2. There were no statistically significant differences between the two groups with respect to Pauwels angle, femoral neck shortening, changes in neck-shaft angle, AVN or nonunion. One reoperation in Group 1 and four in Group 2. Part 2: All five cadaveric specimens in both groups survived the 10,000-cycle loading regimen. We were unable to detect any significant differences between the two groups with respect to construct stiffness, change in neck-shaft angle or amount of femoral neck shortening.

CONCLUSION

Based on the results of both clinical case series and biomechanical testing, an inferomedial neck buttress plate does not appear to offer long-term benefits with respect to maintenance of alignment or achieving union but may potentially help in obtaining the reduction.

How to choose the suitable FNS specification in young patients with femoral neck fracture: A finite element analysis

BACKGROUND

Consensus regarding the optimal approach for the treatment of femoral neck fractures remains lacking. A new internal fixation femoral neck system (FNS) was developed and used in clinical practice. We aimed to investigate the biomechanical outcomes of different types of FNS in the treatment of unstable femoral neck fractures.

METHOD

In this study, we constructed three different types of unstable femoral neck fractures of Pauwels classification with angles of 50°, 60°, and 70°. We set up four test groups, namely, the one-hole plated FNS group, two-hole plated FNS group, inverted cannulated screw group and triangle cannulated screw group. Under 2100 N axial loads, displacements and the von Mises stress of the femur and internal fixation components were measured for each fracture group.

RESULTS

When the Pauwels angle was 50°or 60°, the one-hole locking plated FNS was as superior as the two-hole plated FNS in terms of femur and internal fixation displacement, and the inverted cannulated screw had slightly better stability than the triangular cannulated screw. However, when the angle increases to 70°, the two-hole locking plate has the minimum displacement, followed by the triangular cannulated screw and inverted cannulated screw, which is the worst displacement for the single-hole locking plate. Regardless of the angle, the two sets of FNS have higher internal fixation stress than the two sets of cannulated screws, which is approximately 1.6-3.0 times that of the cannulated screw group.

CONCLUSION

From the perspective of biomechanics, we suggest that when the angle of the fracture line is less than 60°, both single-hole locking plated or double-hole locking plated FNS can be used to treat unstable femoral neck fractures. However, when the angle of the fracture line is greater than 70°, we recommend using a double-hole locking plated FNS. This result needs further verification in further clinical studies.

Treatment and outcomes of basicervical femoral neck fractures: A systematic review

PURPOSE

This study aims to systematically review the literature comparing surgical treatments options and respective failure rates for basicervical hip fractures.

METHODS

A comprehensive search of databases, including MEDLINE, Embase, Web of Science, and Cochrane Central for studies published in English on or before June 21, 2019 was performed. Selected search terms included "basicervical," "basi cervical," "AO/OTA type 31-B," "femoral neck fracture" AND "bone nails," "bone screws," "fracture fixation," "internal fixation," "arthroplasty," "cephalomedullary," "sliding hip screw," "ORIF," and "treatment outcome." We included studies that assessed outcomes of basicervical fracture fixation using open reduction internal fixation or arthroplasty. Two authors extracted the following data from each paper: study design, country, cohort year, definition of basicervical, intervention type, sample size, patient demographics, follow-up length, percent of fractures that required revision, and the percent of implants that failed.

RESULTS

Sixteen articles encompassing 910 patients were included. The main outcome was the percent of implants that required revision. The total revision rates were 8% (8 studies, 157 patients, range 0%-55%) for cephalomedullary nails, 7% (10 studies, 584 patients, range 0%-18%) for sliding hip screws, 23% (3 studies, 40 patients, range 16%-50%) for cannulated screws, 0% (1 study, 6 patients) for total hip arthroplasty, and 8% (2 studies, 13 patients, range 0%-11%) for hemiarthroplasty.

CONCLUSION

Management of basicervical fractures with SHS and CMN produces similar failure and re-operation rates. Limited evidence is available on the use of cannulated screws and arthroplasty, but available studies suggest that cannulated screws have an unacceptable revision rate (23%) while arthroplasty may be acceptable. Future studies examining the comparative efficacy of various fixation methods would benefit from strict definition of fracture type as well as consistent reporting of functional outcomes, re-operation rates, and mortality.

Influence of surgical quality (according to postoperative radiography) on mortality, complications and recovery of walking ability in 1425 hip fracture patients

PURPOSE

To evaluate the influence of surgical quality (as evaluated in the post-surgical radiographic control) on mortality, complications and recovery of walking ability in patients older than 64 years with hip fracture.

PATIENTS AND METHODS

Retrospective observational study of a single-center, consecutive cohort of 1425 patients operated from December/2012 to March/2018. Average age was 85.66±7.13 (65-108) years and 966 (67.86%) were female. Extracapsular fractures (811 cases, 56.91%) were fixed with trochanteric nails (Affixus-DePuy / PFNA-Synthes) (795 cases) or sliding-hip-screw-plates (Biomet) (16 patients). Intracapsular fractures (614, 43.09%) were treated with cannulated screws (Smith-Nephew) (134 cases) or with arthroplasty (472 bipolar and 8 total hip, Furlong-JRI or Exeter-Stryker). Postoperative radiographs were used to determine surgical quality (reduction, compression, screw position, tip-apex, stem position, Voss, intraoperative fracture). Patients were followed clinically and radiographically in outpatient clinic after 1, 3, 6, and 12 months.

STATISTICAL ANALYSIS

Bivariate analysis (Pearson, Fischer, Mann-Whitney, Wilcoxon) was applied to study statistically significant relations, and Relative Risks (RR) were calculated.

RESULTS

196 patients (13.75%) died along follow-up, and poor reduction was found to be a risk factor for mortality both in trochanteric nail group (p=0.0495) (RR 1.510, 1.01-2.26) and in cannulated screw group (p=0.0023) (RR 6.48, 2.40-17.53); this is a previously non-published risk factor. Surgical complications included 33 infections (2.36%), 12 non-unions (1.27%), 12 cut-outs (1.47%), 7 broken nails (0.86%), 21 hemiarthroplasty dislocations (4.37%), and 8 ischemic necrosis of the femoral head (5.97%). The significant risk factors were: poor reduction for trochanteric nail breakage (p=0.041) (RR 4.47, 1.13-17.67), poor reduction for non-union in cannulated screws (p=0.035) (RR 10.91, 1.70-70.09), as well as "tip-apex distance" over 25mm in trochanteric fractures for "cut-out" type of fixation failure (p=0.0159) (RR 3.84, 1.19-12.40). Previous walking ability was restored in 564 patients (39.58%) and worsened in 581 (40.77%), but statistical relationships were not found, although follow-up data were inadequate in 212 cases (14.88%).

CONCLUSIONS

Appropriate reduction of hip fractures is a significant step to reduce mortality, nail breakage and non-union. Adequate position of sliding screw (avoiding tip-apex distances over 25mm) is important to reduce "cut-out" in trochanteric fractures.

Comparison of Ordinary Cannulated Compression Screw and Double-Head Cannulated Compression Screw Fixation in Vertical Femoral Neck Fractures

Background

The treatment of vertical femoral neck fractures in young patients remains a challenge. This study is aimed at comparing ordinary cannulated compression screw (OCCS) and double-head cannulated compression screw (DhCCS) fixation in vertical femoral neck fractures both clinically and biomechanically.

Materials and Methods

Clinically, the radiographs of 81 patients with Pauwel's III femoral neck fractures, including 54 fractures fixed with three parallel OCCSs and 27 fractures fixed with three parallel DhCCSs, were reviewed retrospectively. Complications consisting of fixation failure (screw loosening, obvious fracture displacement, varus deformity, or femoral neck shortening), bony nonunion, and avascular necrosis (AVN) were determined. Biomechanically, twenty synthetic femur models of vertical femoral fractures with an 80° Pauwel's angle were divided into two groups and subsequently fixed with three parallel OCCSs or DhCCSs. All specimens were tested for axial stiffness, load to 5 mm displacement, and a maximum load to failure with a loading rate of 2 mm/min.

Results

Clinically, 22 fractures in the OCCS group experienced fixation failure, including 19 screw loosening, 18 femoral neck shortening, 14 varus deformities, and 8 obvious fracture displacements, whereas only 4 fractures experienced fixation failure in the DhCCS group, including 3 screw loosening, 3 femoral neck shortening, 3 varus deformities, and 1 obvious fracture displacement. Additionally, 11 fractures in the OCCS group exhibited nonunion, whereas only 3 in the DhCCS group exhibited nonunion. Nine fractures with AVN were noted in the OCCS group, whereas only 1 was observed in the DhCCS group. Biomechanically, the axial stiffness of the DhCCS group was greater than that of the OCCS group (154.9 ± 6.81 vs. 128.1 ± 7.41 N/mm), and the load to 5 mm displacement was also significantly greater in the DhCCS group (646.1 ± 25.87 vs. 475.8 ± 21.46 N). Moreover, the maximum load to failure in the DhCCS group exhibited significant advantages compared with that of the OCCS group (1148 ± 39.47 vs. 795.9 ± 51.39 N).

Conclusion

Our results suggested that using three DhCCSs improved the outcome of vertical femoral neck fractures compared to three OCCSs, offering a new choice for the treatment of femoral neck fracture.

Comparison of perioperative hidden blood loss for intertrochanteric fractures in the elderly by different intramedullary fixations: A randomized controlled study protocol

BACKGROUND

Till date only a few studies have reported the clinical outcomes of intraoperative hidden blood loss of intertrochanteric fracture in the old people treated with various intramedullary immobilizations. The aim of the trial is to investigate the best choice for treating intertrochanteric fractures, as well as the hidden blood loss among different intramedullary fixations.

METHODS

This randomized, single-blind, superiority clinical trial was admitted by the Ethics Committee in our hospital (The 7th Medical Center of PLA, 20200602DM). The eligibility criteria were:Patients who met any of the following conditions would not be able to participate in the test: composite femoral fracture, under 65 years of ages, experience of femoral fractures, surgical contraindications, nonambulatory before the presenting injury, or presence of any other traumatic fractures. 120 participants with unstable intertrochanteric fractures, treated by Gammar nail, (n = 40), Proximal Femoral Nail Antirotation (n = 40) and Intertrochanteric Antegrade Nail (n = 40) instruments were enrolled in this research. The main outcome measures were total blood loss and hidden blood loss, which were evaluated based on the haematocrit change after the operation. The experimental data was analyzed and sorted out with SPSS program (ver.19; SPSS Inc., Chicago, IL).

RESULTS

This experiment had strict inclusive criteria and exclusive criteria and a well- regulated intervention.

CONCLUSIONS

The results of this trial will provide more evidence on which technique can better treat unstable intertrochanteric fracture.

TRIAL REGISTRATION

This study protocol was registered in Research Registry (researchregistry5788).

Lag screw with DHS (LSD) for vertical angle femoral neck fractures in young adults

Vertical Pauwels Type III fractures of the neck of femur in young patients are difficult fractures to treat. These are usually as a result of high energy trauma which are associated with a significant degree of fracture comminution in the neck of femur. This makes the fracture reduction and fixation difficult. Many fixation methods and implants have been described for use in these fractures but are not without reported complications such as non-union and varus collapse. In this article, we highlight the incidence of fracture comminution in both the anterior and posterior cortices of the femoral neck, better visualised with axial computed tomography scanning and describe a simple technique utilizing lag screws and a DHS implant to adequately address these fractures.

Biomechanical analysis for five fixation techniques of Pauwels-III fracture by finite element modeling

BACKGROUND AND OBJECTIVES

There are many fixation methods for Pauwels- III fracture, the most common implants are Locking Plate (LP), Dynamic Hip Screw (DHS), Multiple Lag Screw (MLS), and mixed fixture (DHS+MLS) implants, the common procedure is HemiArthroplasty (HA). However, how these fixtures biomechanically function is not clear. The aims of this study are to compare the mechanical behaviors of these five implants by finite element modeling and determinate the most suitable procedure for individuals with Pauwels- III fractures.

METHODS

We gathered 20 sets of femur images from CT scans in the *.dicom format first, and then processed them by using reverse engineering software programs, such as Mimics, Geomagic Studio, UG-8, Pro-Engineer and HyperMesh. Finally, we assembled and analyzed the five types of fixture models, the LP, DHS, MLS, DHS+LS and HA models, by AnSys.

RESULTS

These numerical models of Pauwels III fractures, including fixators and a simulative HA, were validated by a previous study and a cadaver test. Our analytical findings include the following: the displacements of all fixtures were between 0.3801 and 1.0834 mm, and the differences were not statistically significantly different; the resulting average peaks in stress were e(Ha) = 43.859 ≤ d(LP) = 60.435 ≤ b(MLS) = 68.678 < c(LS+DHS) = 98.478 < a(DHS) = 248.595 in Mpa, indicating that the stress of DHS and DHS+LS are greater than those of LP, HA and MLS, while the last 3 models were not significantly different.

CONCLUSIONS

To optimize the treatment for Pauwels III factures clinically, HA and LP should be proposed.

Eliminating projection error of measuring Pauwels' angle in the femur neck fractures by CT plane manipulation

OBJECTIVES

The aim for the present study was to determine whether projection error of measuring Pauwels' angle in young femur neck fracture could be eliminated by CT plane manipulation.

METHODS

Clinical data of displaced femur neck fractures in young adults aged 20 to 64years old (13 females and 17 males) were retrospectively analyzed. Their average age was 47.9years (range: 22-64years; SD: 11.3). Using modified measurement method for Pauwels' angle using central line of the shaft as a guideline, the angle of a conventional coronal CT image was measured. CT images were imported into Mimics® software. The scanning plane was then reformatted parallel to the neck axis to eliminate projection error of injured limb. Measured angles were classified into three types (I<30°; II, 30-50°; and III>50°) and differences were analyzed.

RESULTS

Average Pauwels' angle was 52.9° (range: 28.6-68.3°; SD: 9.9; type II, 17 cases; type III, 13 cases) for conventional CT images and 68.7° (range: 29.8-91.2°; SD: 13.4; type II, 1 cases; type III, 29 cases) for reformatted CT images. Difference between these two measurements on average was 15.7° (range: 1.2-34.9°; SD: 7.3).

CONCLUSIONS

Reformatting CT scanning plane by manipulating the proximal fragment to be parallel with the neck axis of the distal neck-shaft fragment is a convenient and reliable technique for eliminating the projection error of measuring Pauwels' angle in the femur neck fractures.

LEVEL OF EVIDENCE

IV, cohort study.

Hybrid triad provides fracture plane stability in a computational model of a Pauwels Type III hip fracture

The study utilized finite element method to determine displacements and stresses in a set of Pauwels Type III femoral neck fractures repaired using 3 techniques (cannulated screws (Triad), sliding hip screw (SHS), and a Hybrid (SHS + cannulated screws). The research found that shear displacement doubled between the 65° and 75° fracture angles regardless of fixation construct. The SHS alone was the least stable construct, with highest construct stresses and shear displacement along the fracture plane. The stability of the Hybrid and Triad constructs were similar, but stress in the Hybrid was lower suggesting it would provide a higher load to failure than the Triad.

COMPARATIVE ANALYSIS FOR THREE FIXTURES OF PAUWELLS-II BY THE BIOMECHANICAL FINITE ELEMENT METHOD

Little is known about why and how biomechanics govern the hypothesis that three-Lag-Screw (3LS) fixation is a preferred therapeutic technique. A series models of surgical internal-fixation for femoral neck fractures of Pauwells-II will be constructed by an innovative approach of finite element so as to determine the most stable fixation by comparison of their biomechanical performance. Seventeen sets of CT scanned femora were imported onto Mimics extracting 3D models; these specimens were transferred to Geomagic Studio for a simulative osteotomy and kyrtograph; then, they underwent UG to fit simulative solid models; three sorts of internal fixators were expressed virtually by Pro-Engineer. Processed by Hypermesh, all compartments were assembled onto three systems actually as “Dynamic hip screw (DHS), 3LS and DHS+LS”. Eventually, numerical models of Finite Elemental Analysis (FEA) were exported to AnSys for solution. Three models for fixtures of Pauwells-II were established, validated and analyzed with the following findings: Femoral-shaft stress for [Formula: see text](3LS) is the least; Internal-fixator stress (MPa) for [Formula: see text]; Integral stress (MPa) for [Formula: see text]; displacement of femoral head (mm) for a[Formula: see text](DHS+LS) = 0.735; displacement of femoral shaft (mm) for [Formula: see text]; and displacement of fixators for [Formula: see text]. Mechanical comparisons for other femoral parks are insignificantly different, and these data can be abstracted as follows: the stress of 3LS-system was checked to be the least, and an interfragmentary displacement of DHS+LS assemblages was assessed to be the least”. A 3LS-system should be recommended to clinically optimize a Pauwells-II facture; if treated by this therapeutic fixation, breakage of fixators or secondary fracture is supposed to occur rarely. The strength of this study is that it was performed by a computer-aided simulation, allowing for design of a preoperative strategy that could provide acute correction and decrease procedure time, without harming to humans or animals.

Comparison of three different internal fixation implants in treatment of femoral neck fracture-a finite element analysis

Background

Current surgical interventions for the femoral neck fracture are using either cannulated screws (CCS) or a single large screw at a fixed angle with a side-plate (i.e., a sliding hip screw, AKA dynamic hip screw, DHS). Despite these interventions, the need for reoperation remains high (10.0–48.8%) and largely unchanged over the past 30 years. Femoral neck fracture is associated with substantial morbidity, mortality, and costs.

Methods

In this study, our group designed a plate that combines the strength of both CCS and sliding hip screw, through providing three dynamic screws at a fixed angle with a side-plate, namely the slide compression anatomic place-femoral neck (SCAP-FN). Finite element analyses (FEA) were carried out to compare the outcomes of the combination of our SCAP-FN plate with DHS+DS (derotational screw) and to those of using cannulated screws alone.

Results

SCAP-FN produces more stable fixation with respect to the femur and the stress distributions, stress peaks, and rotational angles.

Conclusions

The FEA encouraged us that in the following biomechanical experiment, SCAP-FN may remain the strengths of both CCS and DHS+DS and show a better performance in resisting shearing and rotational forces, therefore achieving the best stability in terms of smallest displacement and rotational angle.

Electronic supplementary material

The online version of this article (10.1186/s13018-019-1097-x) contains supplementary material, which is available to authorized users.

Comparative analysis for five fixations of Pauwels-I by the biomechanical finite-element method

Background: Little is known about how biomechanics govern the five fixtures such as DHS, MLS, DHS + LS, LP, and HA are accepted as common therapeutic techniques. Aims and objectives: A series of numerical models for a femoral neck fracture of Pauwels-I will be constructed by innovative approach of finite element in order to determine the most optimized option in comparison with biomechanical performance. Method: Twenty sets of computer tomography scanned femora were imported onto Mimics to extract 3 D models; these specimens were transferred to Geomagic-Studio for a simulative osteotomy and kyrtograph; then, they underwent UG to fit simulative solid models; 5 sorts of fixture were then expressed by Pro-Engineer virtually. After processing with HyperMesh, all compartments (fracture model + internal implant) were assembled onto 5 systems: "Dynamic Hip Screw (DHS), Multiple Lag screw (MLS), DHS + LS, femoral Locking Plate (LP) and HemiArthroplasty (HA)." Eventually, numerical models of the finite-elemental analysis were exported to AnSys to determine the solution. Result: Four models of fixation and a simulation of HA for Pauwels-I were established, validated, and analyzed with the following findings: In term of displacement, these 5 fixtures ranged between 0.3801 and 0.7536 mm have no significant difference; in term of stress, the averages of peaks for integral assemblage are b(MLS) = 43.5766 ≈< d(LP) = 43.6657 ≈< e(Ha) = 43.6657 < c(DHS + LS) = 66.5494 < a(DHS) = 105.617 in MPa indicate that MLS, LP and HA are not significantly different, but less than DHS + LS or DHS in each. Conclusion: A fixture of MLS or LP with optional HA should be recommended to clinically optimize a Pauwels-I facture.

A 10-Year Retrospective Study of 490 Hip Fracture Patients: Reoperations, Direct Medical Costs, and Survival

BACKGROUND AND AIMS

Reoperations after operative treatment of hip fracture patients may be associated with higher costs and inferior survival. We examined the acute hospital costs, long-term reoperation rates, and survival of patients with a new hip fracture.

MATERIALS AND METHODS

A total of 490 consecutive new hip fracture patients treated at a single center between 31 December 2004 and 6 December 2006 were analyzed retrospectively. Fractures were classified according to Garden and AO. All medical records were checked manually. The costs of reoperations were calculated using the diagnosis-related groups (DRG)-based prices. Survival analysis was performed using the life-table method. The follow-up time was 10 years.

RESULTS

In all, 70/490 patients (14.3%) needed reoperations. Of all reoperations, 34.2% were performed during the first month and 72.9% within 1 year after the primary operation. The hemiarthroplasty dislocation rate was 8.5%, and mechanical failures of osteosynthesis occurred in 6.2%. Alcohol abuse was associated with a heightened risk of reoperation. The mean direct costs of primary fracture care were lower than the mean costs of reoperations (€7500 vs €9800). The mortality rate at 10 years was 79.8% among non-reoperated patients and 62.9% among reoperated patients.

CONCLUSIONS

According to our hypothesis, the cost per patient of reoperation in acute care was 31% higher than the corresponding cost of a primary operation. Reoperations increased the overall immediate costs of index fractures by nearly 20%. One-third of all reoperations were performed during the first month and almost 75% within 1 year after the primary operation.

Ordinary Cannulated Compression Screws or Headless Cannulated Compression Screws? A Synthetic Bone Biomechanical Research in the Internal Fixation of Vertical Femoral Neck Fracture

Purpose

The purpose of this study is to verify whether the headless cannulated compression screw (HCCS) has higher biomechanical stability than the ordinary cannulated compression screw (OCCS) in the treatment of vertical femoral neck fractures.

Materials and Methods

30 synthetic femur models were equally divided into 2 groups, with 50°, 60°, and 70° Pauwels angle of femoral neck fracture, under 3D printed guiding plates and C-arm fluoroscopic guidance. The femur molds were fixed with three parallel OCCSs as OCCS group and three parallel HCCSs as HCCS group. All specimens were tested for compressive strength and maximum load to failure with a loading rate of 2 mm/min.

Results

The result showed that there was no significant difference with the compressive strength in the Pauwels angle of 50° and 60°. However, we observed that the maximum load to failure with the Pauwels angle of 50°, 60°, and 70° and the compressive strength with 70° of HCCS group showed better performance than the OCCS group.

Conclusion

HCCS performs with better biomechanical stability than OCCS in the treatment of vertical femoral neck fracture, especially with the Pauwels angle of 70°.

A model to evaluate Pauwels type III femoral neck fractures

While many femoral neck fractures can be reliably treated with surgical intervention, Pauwels III femoral neck fractures in the young adult population continue to be a challenging injury, and there is no consensus on optimal treatment. As such, there are past and ongoing biomechanical studies to evaluate the fixation provided by different constructs for this inherently unstable fracture. While many investigations rely on cadavers to evaluate the biomechanical performance of a construct, significant inter-subject variability can confound the analysis. Biomechanical femur analogs are being used more frequently due to more consistent mechanical properties; however, they have not been stringently evaluated for morphology or suitability for instrumentation. This study sought to determine the variability among composite femoral analogs as well as consistently create a Pauwels III injury and instrument the analogs without the need for fluoroscopic guidance. In total, 24 fourth-generation composite femoral analogs were evaluated for femoral height, neck-shaft angle, anteversion, and cortical thickness. A method was developed to simulate a Pauwels III fracture and to prepare three different constructs: an inverted triangle of cannulated screws, a sliding hip screw, and a hybrid inverted triangle with cannulated screws and a sliding hip screw. Radiographs were utilized to evaluate the variation in implant position. All but one of the morphological parameters varied by <1%. The tip-to-apex distance for all sliding hip screw hardware was 18.8 ± 3.3 mm, and all relevant cannulated screw distances were within 5 mm of the adjacent cortex. All screws were parallel, on average, within 1.5° on anterior-posterior and lateral films. Fourth-generation composite femora were found to be morphologically consistent, and it is possible to consistently instrument the analogs without the use of fluoroscopy. This analog and hardware implantation model could serve as a screening model for new fracture repair constructs without the need for cadaveric tissues or radiologic technology.

Management and treatment of femoral neck stress fractures in recreational runners: a report of four cases and review of the literature

Femoral neck stress fractures (FNSFs) in healthy young subjects are uncommon and most prevalent among long-distance runners and military recruits. Women seem to be at higher risk of developing stress fractures because of possible eating disorders followed by amenorrhea and osteoporosis. This case report describes four young and middle-aged, active female recreational runners who developed stress fractures of the femoral neck. In three of them, with a clinical history of persistent pain in the groin region, which worsened during training, early diagnosis by MRI was considered essential in detecting the fractures. The patients were clinically, metabolically and radiographically evaluated; they were then treated and followed-up at our institution. Only one case was treated conservatively, while the others underwent surgical internal fixation using a screw-plate (DHS®). All of them returned to sport physical activity after a recovery period. Regarding the challenging management of FNSFs, our report highlights the importance of groin pain, especially in athletic females, an early diagnosis by MRI, and a proper classification of these injuries for a correct choice of treatment in order to prevent further dislocation and avoid avascular necrosis of the femoral head. (www.actabiomedica.it)

Management and treatment of femoral neck stress fractures in recreational runners: a report of four cases and review of the literature

Femoral neck stress fractures (FNSFs) in healthy young subjects are uncommon and most prevalent among long-distance runners and military recruits. Women seem to be at higher risk of developing stress fractures because of possible eating disorders followed by amenorrhea and osteoporosis. This case report describes four young and middle-aged, active female recreational runners who developed stress fractures of the femoral neck. In three of them, with a clinical history of persistent pain in the groin region, which worsened during training, early diagnosis by MRI was considered essential in detecting the fractures. The patients were clinically, metabolically and radiographically evaluated; they were then treated and followed-up at our institution. Only one case was treated conservatively, while the others underwent surgical internal fixation using a screw-plate (DHS®). All of them returned to sport physical activity after a recovery period. Regarding the challenging management of FNSFs, our report highlights the importance of groin pain, especially in athletic females, an early diagnosis by MRI, and a proper classification of these injuries for a correct choice of treatment in order to prevent further dislocation and avoid avascular necrosis of the femoral head.

Management and treatment of femoral neck stress fractures in recreational runners: a report of four cases and review of the literature

Femoral neck stress fractures (FNSFs) in healthy young subjects are uncommon and most prevalent among long-distance runners and military recruits. Women seem to be at higher risk of developing stress fractures because of possible eating disorders followed by amenorrhea and osteoporosis. This case report describes four young and middle-aged, active female recreational runners who developed stress fractures of the femoral neck. In three of them, with a clinical history of persistent pain in the groin region, which worsened during training, early diagnosis by MRI was considered essential in detecting the fractures. The patients were clinically, metabolically and radiographically evaluated; they were then treated and followed-up at our institution. Only one case was treated conservatively, while the others underwent surgical internal fixation using a screw-plate (DHS®). All of them returned to sport physical activity after a recovery period. Regarding the challenging management of FNSFs, our report highlights the importance of groin pain, especially in athletic females, an early diagnosis by MRI, and a proper classification of these injuries for a correct choice of treatment in order to prevent further dislocation and avoid avascular necrosis of the femoral head.

Vertical femoral neck fractures in young adults: a closed fixation strategy using a transverse cancellous lag screw

Vertical femoral neck fractures (Pauwels type III classification) in young adults generally occur as a consequence of high-energy trauma and are frequently seen in association with multiple injuries. Considering the controversies regarding the optimal fixation for this fracture, our aim was to evaluate the clinical outcome of a closed fixation strategy for vertical femoral neck fractures in young adults using two parallel and one transverse cancellous lag screws. This was a single-surgeon, prospective study including 20 young adults with average age of 38.75 years (range 18-59 years) with a high-energy Pauwels III femoral neck fracture. Closed reduction and internal fixation with three cancellous lag screws were performed. The first screw was inserted crosswise to avoid further shear forces. Second and third parallel screws were placed above the lesser trochanter and centrally on the greater trochanter, respectively. Clinical outcomes were assessed by comparing postoperative and final follow-up radiographs 24 months post-injury. Eleven patients had an isolated vertical femoral neck fracture. Of these, five had further femoral neck comminution. Nine patients had an associated ipsilateral femoral shaft fracture. All fractures were displaced at the time of the first radiological evaluation. Closed reduction quality was considered excellent or good in 15 patients. After 24 months, bone union was achieved in 16 cases. Osteonecrosis of the femoral head developed in association with two fractures, and a nonunion developed in association with two fractures. We conclude that vertical high-energy femoral neck fractures can be treated successfully with internal fixation with two parallel cancellous lag screws positioned above the lesser trochanter and a third screw inserted centrally on the greater trochanter at an angle perpendicular to the fracture line.

A sliding hip screw augmented with 2 screws is biomechanically similar to an inverted triad of cannulated screws in repair of a Pauwels type-III fracture

OBJECTIVE

Pauwels III femoral neck fractures are highly unstable. These fractures are commonly treated with three cannulated screws or sliding hip screw (SHS) implants, however high rates of non-union persist. A hybrid SHS construct has recently been proposed. The objective of the study was to compare this construct to the familiar inverted triad of cannulated screws and to a single SHS.

METHODS

Fourth generation biomechanical femur analogs were used to create a highly repeatable injury model. The hybrid SHS construct contained a SHS with two superior cannulated screws in an inverted triangle configuration. Eight samples for each construct were biomechanically evaluated and the results compared using ANOVA (p<0.05).

RESULTS

The cannulated triad and hybrid SHS provided similar stiffness and fracture gap motion. The single SHS exhibited significantly lower stiffness and larger fracture plane diastasis than either the inverted triangle of cannulated screws or hybrid SHS (p<0.05). None of the constructs exhibited catastrophic failure during cyclic loading nor under loading up to 2.5 times body weight.

CONCLUSIONS

The single SHS provided the least stable fracture fixation, while the inverted triad and hybrid SHS constructs were mechanically similar. The fracture repair simulated here illustrates how these repairs have the potential to return near pre-fracture strength in ideal conditions with young, healthy bone. However; in clinical situations where comminution impairs load transfer through the cortices the hybrid SHS may be the most favorable option.

A new angle and its relationship with early fixation failure of femoral neck fractures treated with three cannulated compression screws

BACKGROUND

The Pauwels angle has been used widely, however an accurate evaluation of this angle is difficult because of deformity of the affected lower extremity. Therefore we designed a new measurement of the orientation of femoral neck fracture and applied this in a retrospective study to assess: (1) its reproducibility, (2) its advantages compared with the Pauwels angle, (3) its relationship with the short-term prognosis treated with three cannulated compression screws.

HYPOTHESIS

This new measurement is reproducible and has some reference meaning for the treatment of femoral neck fractures.

METHODS

Two hundred and twenty-eight patients with femoral neck fractures treated with three cannulated compression screws were retrospectively analyzed. The VN angle, which was the angle between the fracture line and the vertical of the neck axis, and the Pauwels angle were measured respectively. The method of ICC was performed to assess the reproducibility of the two angles, and the absolute value of difference in pre-operative and post-operative radiographs was used to evaluate the uniformity of the two angles. These fractures were divided into four groups according to VN angle (VN<0° (n=92), 0°≤VN<10° (n=82), 10°≤VN<15° (n=26), VN≥15° (n=28)), and the short-term (within 6 months) fixation results of radiographs in these fractures were evaluated.

RESULTS

The ICC of the VN angle and the Pauwels angle in pre-operative radiographs were 0.937 (95% confidence interval (CI): 0.922-0.950) and 0.942 respectively (95% CI: 0.914-0.970), indicating both angles had a good inter-rater reproducibility. However, there was a great difference between the Pauwels angle in pre-operative and post-operative radiographs (P=0.037), the absolute difference was 10.66±6.47 (range: 1.72-38.48), while no statistical difference for the VN angle (P=0.084) and the absolute difference was 2.20±1.63 (range: 0.05-7.56). The overall fixation failure rate which was defined as screw loosening, varus collapse, obvious fracture displacement or femoral neck shortening was 11.84%, and the mean failure rates according to VN angles were respectively 0%, 3.24% (95% CI: 1.64-4.84), 22.69% (95% CI: 16.43-28.96), 65.45% (95% CI: 59.36-71.53). The mean failure rates of fractures according to post-operative Pauwels angle (<30°, 30-50°, >50°) were respectively 0%, 1.46% (95% CI: 1.42-1.50) and 36.24% (95% CI: 34.93-37.54).

DISCUSSION

The VN angle has a good inter-rater reproducibility, a higher reliability than the Pauwels angle and is closely related to the short-term prognosis of femoral neck fractures treated with cannulated compression screws.

LEVEL OF EVIDENCE

Level IV, retrospective diagnostic study.

Lower limb stress fractures in sport: Optimising their management and outcome

Stress fractures in sport are becoming increasing more common, comprising up to 10% of all of sporting injuries. Around 90% of such injuries are located in the lower limb. This articles aims to define the optimal management of lower limb stress fractures in the athlete, with a view to maximise return rates and minimise return times to sport. Treatment planning of this condition is specific to the location of the injury. However, there remains a clear division of stress fractures by “high” and “low” risk. “Low risk” stress fractures are those with a low probability of fracture propagation, delayed union, or non-union, and so can be managed reliably with rest and exercise limitation. These include stress fractures of the Postero-Medial Tibial Diaphysis, Metatarsal Shafts, Distal Fibula, Medial Femoral Neck, Femoral Shaft and Calcaneus. “High risk” stress fractures, in contrast, have increased rates of fracture propagation, displacement, delayed and non-union, and so require immediate cessation of activity, with orthopaedic referral, to assess the need for surgical intervention. These include stress fractures of the Anterior Tibial Diaphysis, Fifth Metatarsal Base, Medial Malleolus, Lateral Femoral Neck, Tarsal Navicular and Great Toe Sesamoids. In order to establish the optimal methods for managing these injuries, we present and review the current evidence which guides the treatment of stress fractures in athletes. From this, we note an increased role for surgical management of certain high risk stress fractures to improve return times and rates to sport. Following this, key recommendations are provided for the management of the common stress fracture types seen in the athlete. Five case reports are also presented to illustrate the application of sport-focussed lower limb stress fracture treatment in the clinical setting.

Femoral Neck Stress Fractures in Sport: A Current Concepts Review

Femoral neck stress fractures (FNSFs) account for 3% of all sport-related stress fractures. The commonest causative sports are marathon and long-distance running.

The main types of FNSF are compression-sided, tension-sided and displaced. The most common reported symptom is exercise-related groin pain. Radiographs form the first line of investigation, with MRI the second-line investigation.

The management of FNSFs is guided by the location and displacement of the fracture. Delay in diagnosis is common and increases the likelihood of fracture displacement. Sporting outcomes are considerably worse for displaced fractures. Education programmes and treatment protocols can reduce the rates of displaced FNSFs.

This article aims to provide a current concepts review on the topic of FNSFs in sport, assess the current evidence on the epidemiology and pathophysiology of these injuries, detail the current recommendations for their imaging and management, and review the recorded sporting outcomes for FNSFs in the existing literature.

From this study, we conclude that although FNSFs are a rare injury, they should be considered in all athletes presenting with exercise-related hip pain, because delay in diagnosis and subsequent fracture displacement can significantly impair future return to sport. However, when detected early, FNSFs show promising results in terms of return-to-sport rates and times.

Mechanical analysis of femoral neck fracture fixation with dynamic condylar screw in synthetic bone

Objective:

To analyze statistically results in biomechanical testing of fixation of femoral neck Pauwels type III fractures, on synthetic bone, with dynamic condylar screw (DCS) and control group.

Methods:

Ten synthetic bones of a national brand were used. Test Group: fixation was performed after osteotomy at 70^o tilt using DCS plate with four holes. We analyzed the resistance of this fixation with 5 mm displacement and rotational deviation (Step 1) and with10 mm (Step 2). Control group: the models were tested in their integrity until the femoral neck fracture occurred.

Results:

The values of the test group in Step 1 showed a mean of 974N and SD = 114N. In Stage 2, we obtained on average 1335N and SD = 98N. The values in the control group were: 1544N, 1110N, 1359N, 1194N, 1437N, respectively. Statistical analysis using the Mann-Whitney test for comparison of the maximum force (N) between the test group and the control, in Step 2, demonstrated that there is no significant difference between the DCS and control plates (p = 0.91).

Conclusion:

There is no significant difference between the DCS boards and the control group exposed to full resistance. Level of Evidence III, Case Control.

Inflammatory bowel disease, high-dose steroids, osteoporosis, or an oncological etiology for a pathological femoral neck fracture in a young adult: a case report

Femoral neck fractures occur in approximately 6,000 of young adults annually (ages 18-49) (1). Of these, a high-energy traumatic event is the typical cause. Although medications and chronic diseases have been implicated as confounding causes of hip fractures, clinicians should have a high index of suspicion for an oncologic etiology of hip fractures occurring in young patients without an inciting traumatic event.

An 8-year follow-up study of 221 consecutive hip fracture patients in Finland: analysis of reoperations and their direct medical costs

BACKGROUND

Some hip fracture patients need one or more reoperations because of complications following initial operative treatment.

AIMS

The aim of this study was to identify all further surgical interventions in a cohort of patients with hip fractures over a period of 8 years after index fracture. Immediate direct costs of these reoperations were also calculated.

MATERIAL AND METHODS

This retrospective study investigated 221 consecutive patients with hip fractures operated on at two different hospitals in southeastern Finland. The study period in hospital A was from 1 February 2003 to 31 January 2004, and in hospital B from 1 February 2003 to 30 April 2004. About 50% were femoral neck fractures, 41% trochanteric fractures, and 9% subtrochanteric fractures. Patients' medical records were checked from the hospital records and confirmed manually. Short- and long-term complications were recorded. Survival analysis was performed using a life-table method. The actual costs for reoperations and other further procedures for each patient were calculated using diagnosis-related groups-based costs for both hospitals in 2012.

RESULTS

A total of 20 patients (9%) needed reoperations. Overall, 10 patients (8.9%) with a femoral neck fracture (n = 112), 8 patients (8.7%) with trochanteric fracture (n = 92), and 2 patients (10.5%) with subtrochanteric fracture (n = 19) were reoperated on. The median interval between the primary operation of the acute hip fracture (n = 20) and the first reoperation was about 300 days (range: 2 weeks to 82 months). Among the women reoperated on, the excess mortality was lower than among those undergoing a single operation. The median costs of treatment per patient with one or more reoperations were €13,422 in hospital A (range: €1616-€61,755), €11,076 in hospital B (range: €1540-€17,866), and €12,850 in the total study group (p = 0.43). In the case of infections (3 patients), the mean costs per patient were €28,751 (range: €11,076-€61,755).

CONCLUSIONS

Almost 10% of hip fracture patients required reoperations, and these reoperations caused significant direct costs to health care. However, direct costs account for only approximately 25% of the first year's total costs. These costs should be taken into account when evaluating the economics of hip fractures and the burden of health care.