Nonanatomical reduction of displaced subcapital femoral fractures (Gotfried reduction)

Biomechanical comparison of Gofried positive support reduction of Pauwels type III femoral neck fractures: A finite elements analysis

OBJECTIVE

This study aims to investigate the biomechanical characteristics of non-anatomical reduction and different screw positions on the stability of Pauwels type III femoral neck fractures.

METHODS

Three-dimensional finite element models of femoral neck fractures were constructed using CT images. Four types of internal fixation methods were simulated, including biplane double-supported screw fixation (BDSF), three inverted triangular parallel cannulated screws (3CS), new parallel cannulated screws with posterior screws moving down (New 3CS), and two parallel cannulated screws (2CS). von Mises stress and total displacement were compared between the fracture models after the femoral head was subjected to an axial load of 2100 N. Stress and displacement data for the implants and the femur were recorded for each fixation method and compared.

RESULTS

The results demonstrated that positive reduction of a Pauwels type III femoral neck fracture provided greater stability than neutral or negative reduction. Specifically, the BDSF group showed the lowest maximum von Mises stress in the femur (17.66 MPa) in positive reduction, compared to 3CS (21.08 MPa), New 3CS (22.14 MPa), and 2CS (36.57 MPa). The total displacement of positive reduction in the BDSF group was 0.3143 mm, which was lower than in the 3CS (0.3498 mm), New 3CS (0.3343 mm), and 2CS (0.4533 mm) groups. The stress distribution in the positive support reduction group was lower than that of the other groups, indicating better load distribution. Among the three-screw fixation methods, the New 3CS system exhibited the highest stress in the screws (with a peak of 28.62 MPa), while the 2CS group displayed the highest stresses overall, both in the femur and the screws.

CONCLUSION

For Pauwels type III femoral neck fractures, a positive support reduction with BDSF fixation exhibited superior biomechanical performance than negative reduction. Based on the finite element analysis conducted in this study, the positive support reduction with BDSF fixation can enhance fixation stability, suggesting that non-anatomical reduction is recommended.

Biomechanical investigation of positive reduction in the femoral neck fracture: a finite element analysis

Background

Gotfried positive reduction offers an alternative strategy for femoral neck fracture (FNF) when achieving anatomical reduction is challenging. However, the biomechanical consequences of positive reduction remain unclear. The purpose of this study was to investigate the biomechanical behavior of positive reduction across different Pauwels classification, providing a reference for quantifying positive reduction in clinical practice.

Methods

Three-dimensional (3D) models of FNF were established and categorized according to the Pauwels classifications (Pauwels I, II, and III), each of them contained seven models with different reduction qualities, including an anatomical reduction model, two negative reduction models, and four positive reduction models, all of which were stabilized with dynamic hip screws (DHS) and cannulated screws (CS). We investigated the maximal von-Mises stress of internal fixation and proximal femoral, femoral fragment displacement, and maximal von-Mises strain at the proximal fragment fracture site when a 2100 N load was applied to the femoral head.

Results

The maximum von-Mises stress on the internal fixators in each Pauwels group was lowest in the anatomical reduction model. In the Pauwels I group, positive reduction exceeding 3 mm resulted in the maximum von-Mises stress on the internal fixators surpassing that of the negative reduction model. For the Pauwels II group, positive reduction beyond 2 mm led to the maximum von-Mises stress on the internal fixators exceeding that of the negative reduction model. In the Pauwels III group, positive reduction beyond 1 mm caused the maximum von-Mises stress on the internal fixators to be higher than that of the negative reduction model. The maximum von-Mises strain at the fracture site of proximal femur fragment increased with positive reduction. Varus displacement increased in positive reduction models as the Pauwels angle rose, potentially exacerbating rotation deformity in Pauwels III group.

Conclusion

Excessive positive reduction may increase the risk of FNF failure after internal fixation. From a biomechanical stability perspective, positive reduction should be limited to 3 mm or below in the Pauwels I group, restricted to not exceed 2 mm in the Pauwels II group, and should not exceed 1 mm in the Pauwels III group. Negative reduction should be avoided in all Pauwels groups.

Anteromedial cortical support reduction of intertrochanteric fractures-A review

The intertrochanteric fracture is a common fragility fracture typically resulting from low-energy falls. The functional outcome of intertrochanteric fractures is closely linked to the patient's underlying physical condition, intraoperative procedures, and postoperative complications. In terms of surgery, while timely surgery and appropriate internal fixation have demonstrated favorable outcomes, attention to intraoperative reduction is crucial. In recent years, there have been further developments in the evaluation of reduction of intertrochanteric fractures, particularly in the anteromedial cortical reduction, and these advances have been further scientifically elucidated in terms of their ability to provide stable fracture reduction and resist loss of reduction. In order to gain a comprehensive understanding of the anteromedial cortex theory, this article reviewed the anatomy, related theoretical progress, and controversies in recent years.

Anti-Shortening Screw for the Prevention of Postoperative Shortening in Displaced Femoral Neck Fractures: A Retrospective Cohort Study

BACKGROUND

Early femoral neck shortening after femoral neck system (FNS) fixation for displaced femoral neck fractures can occur in 22.3%-39.1% of cases, leading to decreased hip joint function. This study aimed to investigate the effectiveness of using an anti-shortening screw (ASS) in FNS fixation to prevent postoperative femoral neck shortening in displaced femoral neck fractures.

METHODS

We retrospectively analyzed 106 cases of displaced femoral neck fractures treated with FNS at the Hospital from April 2020 to April 2023. Patients were divided into two groups based on the use of an ASS: the traditional group and the ASS group, each consisting of 53 cases. The ASS group was age-matched with the traditional group treated during the same period without an ASS. The study variables included age, sex, body mass index (BMI), smoking and drinking history, injury mechanism, side of injury, fracture type, surgical time, intraoperative blood loss, Harris Hip Score (HHS) at the final follow-up, radiographic assessment (femoral neck shortening), and complications (infection, femoral head necrosis, nonunion, and secondary surgery). Statistical analysis was performed using SPSS software, with continuous and categorical variables analyzed using appropriate parametric (t-test) and nonparametric (Mann-Whitney U test) tests, and chi-square or Fisher's exact tests, respectively. A p-value <0.05 was considered significant.

RESULTS

There were no significant differences in background characteristics between the traditional and ASS groups. The shortening distance at postoperative day 1 did not differ significantly between the two groups (0 vs. 0 mm, p = 0.120). However, at 1, 3 months, and 1 year postoperatively, the femoral neck shortening in the ASS group was significantly less than that in the traditional group (1 month: 2.3 vs. 3.1 mm, p = 0.007; 3 months: 2.6 vs. 3.5 mm, p = 0.005; 1 year: 2.6 vs. 3.5 mm, p = 0.002). The ASS group also had a significantly lower shortening distance during the fracture healing process (0.9 vs. 2.7 mm, p = 0.005). The incidence of moderate to severe shortening (≥5 mm) at 1 year postoperatively was lower in the ASS group compared with the traditional group (15.1% vs. 37.7%, p = 0.001). The ASS group had a longer surgical time (63.0 ± 13.4 vs. 73.0 ± 23.2 min, p = 0.008) and a higher HHS (90.7 vs. 94.8, p = 0.008). There was no significant difference in fracture healing time or postoperative complications between the two groups. The traditional group had 3.8% cutouts, 7.5% nonunions, 5.7% avascular necrosis, and 7.5% secondary hip replacements. The ASS group saw 0% cutouts, 1.9% nonunions, 3.8% avascular necrosis, and 3.8% hip replacements. No significant differences in complication rates (p > 0.05).

CONCLUSION

The use of an ASS in FNS fixation for displaced femoral neck fractures can reduce the degree of postoperative shortening and improve hip joint function.

Nonanatomical reduction of femoral neck fractures in young patients with different Pauwels classifications: a retrospective study and finite element analysis

BACKGROUND

Previous studies have reported that positive buttress is as effective as anatomical reduction in treating young femoral neck fractures, but whether this effect is related to the Pauwels classification remains unclear. The purpose of this study was to retrospectively analyze the clinical prognosis of positive buttress in young femoral neck fractures with different Pauwels classifications, as well as to assess its biomechanical properties.

METHODS

A total of 170 young patients with femoral neck fractures who were treated with three cannulated screws were included in this study. Patients were divided into three groups based on their preoperative Pauwels classification. Each group was divided into three subgroups based on the reduction quality: positive buttress, negative buttress and anatomical reduction. The femoral neck shortening, the incidence of necrosis of the femoral head (AVN) and the Harris hip scores at the last follow-up were compared across the three reduction quality within each Pauwels classification. Subsequently, a volunteer was recruited, CT data of the hip was obtained, and finite element models representing different reduction quality under varying Pauwels classifications were established. The biomechanical properties of each model were then evaluated following the application of strains.

RESULTS

In Pauwels type I, there were no significant differences in postoperative femoral neck shortening, incidence of AVN, or Harris score among the three types of reduction quality (P > 0.05). However, positive buttress provided superior biomechanical stability compared to negative buttress and anatomical reduction. In Pauwels type II, the incidence of AVN was similar between the positive buttress and the anatomical reduction groups, and both were significantly lower than that in the negative buttress (P < 0.05). The Harris score of the positive buttress was higher than that of the negative buttress, and there was no significant difference in the occurrence of femoral neck shortening between the three groups (P > 0.05). Finite element analysis showed that the biomechanical stability of positive buttress was equivalent to anatomical reduction, and both were better than negative buttress. In Pauwels type III, the incidence of AVN in the anatomical reduction group was lower than that in both the positive buttress and negative buttress (P < 0.05). There was no significant difference in the occurrence of AVN or femoral neck shortening between positive buttress and negative buttress (P > 0.05). There was also no difference in postoperative Harris scores between the three reduction qualities (P > 0.05). Both positive buttress and negative buttress exhibited identical biomechanical qualities and were inferior to anatomical reduction.

CONCLUSIONS

The biomechanical and clinical dominance of positive buttress correlates with Pauwels type. Specifically, Positive buttress is biomechanically stable in Pauwels types I and II. In Pauwels type III, positive buttress is not advantageous. As the Pauwels angle increases, the biomechanical benefit of the positive buttress is lost. Therefore, regardless of the Pauwels classification, negative buttress should be avoided after reduction of femoral neck fractures in young patients.

Evaluation of the clinical efficacy of using an inverted triangular cannulated compression screw in combination with positive or negative buttress reduction for the healing of femoral neck fractures

OBJECTIVE

We aimed to compare the clinical efficacy of inverted triangular cannulated compression screws combined with Gotfried positive or negative buttress reduction in the healing of femoral neck fractures.

METHODS

Between October 2017 and March 2021, 55 patients with femoral neck fractures underwent treatment using inverted triangular cannulated compression screws combined with Gotfried positive or negative buttress reduction. Among these patients, 29 received inverted triangular cannulated compression screws combined with Gotfried positive buttress reduction treatment. This group consisted of 16 males and 13 females, with an average age of 43.45 ± 8.23 years. Additionally, 26 patients received inverted triangular cannulated compression nails combined with Gotfried negative buttress reduction treatment. This group included 14 males and 12 females, with an average age of 41.96 ± 8.69 years. Postsurgery, various measurements were taken, including the degree of shortening of the femoral neck, degree of bone nonunion, degree of fixation failure, degree of ischemic necrosis of the femoral head, and Harris score of the hip joint.

RESULTS

All patients were followed up for a minimum of 18 months. The group that underwent treatment with an inverted triangular cannulated compression screw combined with Gotfried positive buttress reduction did not experience any cases of bone nonunion, fixation failure, or ischemic necrosis of the femoral head. In the group that received treatment with inverted triangle cannulated compression screws combined with Gotfried negative buttress reduction, there was one case of bone nonunion, three cases of early fixation failure, and one case of ischemic necrosis. Ultimately, five patients (19.23% of the total) underwent joint replacement surgery. The average shortening lengths in the vertical plane were 4.07 ± 1.98 mm and 8.08 ± 3.54 mm, respectively. In the horizontal plane, the average shortening lengths were 3.90 ± 1.57 mm and 7.77 ± 3.31 mm, respectively. At the last follow-up, the group that received Gotfried positive buttress reduction had a greater Harris hip joint score.

CONCLUSION

The success rate of combining inverted triangular cannulated compression screws with Gotfried positive buttress reduction surgery is relatively high. This surgical approach effectively prevents femoral neck shortening and improves hip joint function. Moreover, it is crucial to avoid negative buttress reduction when managing femoral neck fractures.

A New Postoperative Stability Score to Predict Loss of Reduction in Intertrochanteric Fractures in Elderly Patients

The study aimed to validate a newly developed postoperative stability score for evaluating clinical follow-up in elderly patients with low-energy hip fractures. From 1 January 2020 to 31 December 2021, we enrolled patients aged over 65 who underwent cephalomedullary nail fixation using proximal femoral nail antirotation II (PFNAII) and had at least 6 months of follow-up; excluding multiple fractures, pathological fractures, and periprosthetic fractures. We collected general patient data. Parameters such as TAD, Parker's ratio (AP and lateral), and the new postoperative stability score were recorded. A loss of reduction was defined using the decline in the Chang reduction quality criteria (CRQC) score within one month. Among the 108 enrolled patients, 23 (21.3%) experienced a loss of reduction, with a mean age of 82.1 years and a mean follow-up time of 7.4 months. Univariate analysis showed no significant association between loss of reduction and general data. However, the new postoperative stability score correlated significantly with loss of reduction (mean scores: 6.68 vs. 4.83, p = 0.045). Multivariate analysis confirmed this association (odds ratio: 0.076, 95% confidence interval: 0.022-0.263, p < 0.05). The newly developed postoperative stability score, incorporating surgical technique assessment, improves prediction accuracy for loss of reduction in elderly intertrochanteric fracture (ITF) patients.

Positive buttress reduction in femoral neck fractures: a literature review

BACKGROUND

Femoral neck fractures (FNFs) in young adults are usually caused by high-energy trauma, and their treatment remains a challenging issue for orthopedic surgeons. The quality of reduction is considered an important factor in improving the poor prognosis of patients with FNFs. In recent years, positive buttress closed reduction technique has received widespread attention in the treatment of FNFs. This comprehensive literature review is designed to encapsulate the impacts of both non-anatomic and anatomic reduction on the biomechanical stability, clinical outcomes, and postoperative complications in the management of FNFs, conjecture the efficacy of positively braced reduction techniques and provide a thorough summarization of the clinical outcomes.

METHODS

In this literature review, we have examined all clinical and biomechanical studies related to the treatment of FNFs using non-anatomical reduction or positive and negative buttress reduction. PubMed, Web of Science, Google Scholar and Embase Library databases were searched systematically for studies published before September 1, 2023. Published literature on fracture reduction techniques for treating FNFs was reviewed. In addition, we evaluated the included literature using the MINORs tool.

RESULTS

Although the "arch bridge" structure formed by the positive buttress reduction technique improved the support to the cortical bone and provided a more stable biomechanical structure, no significant differences were noted in the clinical efficacy and incidence of postoperative complications between the positive buttress reduction and anatomical reduction.

CONCLUSION

Positive buttress reduction is an effective treatment method for young patients with FNFs. When facing difficult-to-reduce FNF, positive buttress reduction should be considered first, followed by anatomical reduction. However, negative buttress reduction should be avoided.

Sagittal support rather than medial cortical support matters in geriatric intertrochanteric fracture: A finite element analysis study

Hip fracture, increasing exponentially with age, is osteoporosis's most severe clinical consequence. Intertrochanteric fracture, one of the main types of hip fracture, is associated with higher mortality and morbidity. The current research hotspots lay in improving the treatment effect and optimizing the secondary stability after intertrochanteric fracture surgery. Cortex buttress reduction is a widely accepted method for treating intertrochanteric fracture by allowing the head-neck fragment to slide and rigidly contact the femoral shaft's cortex. Medial cortical support is considered a more effective option in treating young patients. However, osteo-degenerations features, including bone weakness and cortical thickness thinning, affect the performance of cortex support in geriatric intertrochanteric fracture treatment. Literature focusing on the age-specific difference in cortex performance in the fractured hip is scarce. We hypothesized that this osteo-19 degenerative feature affects the performance of cortex support in treating intertrochanteric fractures between the young and the elderly. We established twenty models for the old and the young with intertrochanteric fractures and performed static and dynamic simulations under one-legged stance and walking cycle conditions. The von Mises stress and displacement on the femur, proximal femoral nail anti-rotation (PFNA) implant, fracture plane, and the cutting volume of cancellous bone of the femur were compared. It was observed that defects in the anterior and posterior cortical bone walls significantly increase the stress on the PFNA implant, the displacement of the fracture surface, and cause a greater volume of cancellous bone to be resected. We concluded that ensuring the integrity and alignment of the anterior and posterior cortical bones is essential for elderly patients, and sagittal support is recommended. This finding suggests that the treatment method for intertrochanteric fracture may differ, considering the patient's age difference.

Role of Anteromedial Cortical Support for Unstable Intertrochanteric Fractures Being Treated With Cephalomedullary Nails

INTRODUCTION

Reduction quality is of paramount importance for an optimal outcome in unstable pertrochanteric fractures. The non-anatomical functional anteromedial buttress is proposed to prevent impending mechanical complications. We aimed to evaluate the role of anteromedial cortical support in preventing mechanical complications following fixation with the cephalomedullary nail.

MATERIALS AND METHODS

A prospective, single-arm interventional study was conducted in the Orthopaedics Department of a Combined Military Hospital (CMH) in Rawalpindi. The duration of the study was 24 months. Patients were recruited by the purposive sampling technique as per inclusion/exclusion criteria. Preoperatively, the reduction was categorized as per Baumgartner's and Chang's criteria. Post-operatively, weight bearing as tolerated was advised. Radiographs prior to discharge for loss of reduction were evaluated. Follow-up radiographic measurements of neck length, neck shaft angle, and their loss as per protocol were done at three and six months.

RESULTS

A total of 202 patients were operated on from October 21 until August 23. Mortality at six months in 39 patients (19.3%) and loss to follow-up in 31 patients (15.3%) resulted in 132 patients with complete follow-up and having developed complications in 12 patients (9.09%). The mean age was 76.3 ± 7.98 years; males were 105 (79.5%), and females were 27 (20.5%). Closed reduction was 58 (43.9%), and additional manoeuvres were required in 74 (56.1%). The mean tip apex distance (TAD) was 24.56 ± 2.76, and the Calcar gap was 5.16 ± 1.27. Cleveland zone centre-centre in 54 (40.9%), inferior-centre in 65 (49.2%), and inferior-posterior (9.9%) were statistically significant for mechanical complications (p≤0.001). There was a significant association between the grading of Chang's and Baumgartner's poor groups for the development of mechanical complications (p≤0.001). The mean time to full weight bearing without support was 21 ± 1.22 weeks. The mean Hip Harris score at six months was 69.27 ± 7.68.

CONCLUSION

Results suggest that anteromedial cortical support can lead to fewer potential mechanical complications at six months. A higher Chang's grade drives surgeons to engage in additional manoeuvres. Anteromedial cortical support is worth consideration for unstable pertrochanteric fractures.

Biomechanical Stability of Femoral Neck System for Pauwels Type III Femoral Neck Fractures Based on Different Reduction Quality

To further investigate the biomechanics of a femoral neck system (FNS) for Pauwels type III femoral fractures based on three different reductions.We constructed three different reduction (anatomical reduction, negative buttress reduction, and positive buttress reduction) models of Pauwels type III femoral neck fractures. Then, three cannulated screws (3CS), dynamic hip screws (DHS), dynamic hip screws combined with an anti-rotation screw (DHS + ARS), one-hole femoral neck system (1HFNS), and two-hole femoral neck system (2HFNS) were assembled with the reduction models, respectively, to simulate the internal fixation surgical procedure. All models had a load of 2100 N in line with the femoral mechanical axis applied. The implant stress, the head and implant displacements, and the rotational angles of all models were recorded and analyzed.Compared to 3CS and 2HFNS, 1HFNS had higher implant stress (higher than 92.5 MPa and 46.3 MPa, respectively) and displacement (higher than 0.9 mm and 0.8 mm, respectively) in the anatomical reduction. 2HFNS exhibited the highest stress values (225.5 MPa) in the anatomical reduction but the lowest values (159.8 MPa) in the positive buttress reduction when compared to the other implants. 2HFNS showed the best rotational stability in the negative and positive buttress reduction (rotational angels of 0.8° and 0.6°, respectively).Based on the outcome of this computational study, it might be concluded that 2HFNS was an alternative fixation for the treatment of Pauwels type III femoral neck fracture, especially when anatomical reduction cannot be perfectly attained. More relevant clinical and biomechanical studies are needed in the future.

Clinical observation of Gofried positive buttress reduction in the treatment of young femoral neck fracture: A systematic review and meta-analysis

BACKGROUND

Femoral neck fractures in young adults(<65 years), have always been a difficult problem, characterized by high rates of nonunion and avascular necrosis (AVN). The clinical efficacy of anatomical reduction and non-anatomical reduction methods needs to be supported by clinical data. Therefore, we conduct a meta-analysis on the clinical efficacy of different reduction methods to better guide clinical practice.

METHODS

Relevant studies published using internal fixation to treat femoral neck fracture in several databases were searched. The outcomes sought included Harris score and the rate of AVN, nonunion and femoral neck shortening (<5 mm). Included studies were assessed for methodological bias and estimates of effect were calculated. Potential reasons for heterogeneity were explored.

RESULTS

The clinical results showed that compared with the anatomical reduction and positive buttress, there is no significant difference in the rate of AVN (OR = 0.87, 95%CI: 0.55-1.37, P = .55), nonunion (OR = 0.54, 95%CI: 0.21-1.41, P = .21), femoral neck shortening (<5 mm) (OR = 1.03,95%CI: 0.57-1.86, P = .92), the Harris score (MD = -0.28, 95%CI: -1.36-0.80, P = .61) and the excellent and good rate of Harris score (OR = 1.73, 95%CI: 0.84-3.56, P = .61). However, compared with negative buttress, the rate of AVN (OR = 0.62, 95%CI: 0.38-1.01, P = .05), nonunion (OR = 0.34, 95%CI: 0.12-1.00, P = .05) and femoral neck shortening (<5 mm) (OR = 0.27, 95%CI: 0.16-0.45, P < .00001) were significantly lower, and the Harris score (MD = 6.53, 95%CI: 2.55 ~ 10.51, P = .001) was significantly better in positive buttress.

CONCLUSIONS

In the case of difficult to achieve anatomical reduction, for young patients (< 65 years) with femoral neck fracture, reduction with positive buttress can be an excellent alternative and negative buttress should be avoided as much as possible.

Femoral neck system and cannulated compression screws in the treatment of non-anatomical reduction Pauwels type-III femoral neck fractures: A finite element analysis

BACKGROUND

High shear force is a major factor detrimental to the healing of vertical femoral neck fractures. In addition to firm fixation, reduction quality is crucial for postoperative stability. The present study aimed to compare the biomechanical stability of the newly invented femoral neck system and three inverted-triangle cannulated compression screws treatments for non-anatomical reduction of Pauwels type-III femoral neck fractures.

METHODS

A total of 18 non-anatomical reduction Pauwels type-III femoral neck fracture finite element models were fabricated and fixed using three inverted-triangle cannulated compression screws or the femoral neck system. A 1950-N force was applied to the femoral head to simulate the physiological load during a single-leg stance. Parameters of the maximum total deformation, the interfragmentary gap, and the maximum von Mises stress of the implants and the proximal femur were analyzed.

FINDINGS

The results of the maximum total deformation, interfragmentary gap, and maximum von Mises stress of the implants in the negative-negative buttress model fixed by the femoral neck system were the largest among all groups (3.58 mm, 0.252 mm, and 729.68 MPa, respectively). In contrast, the anatomical-anatomical reduction model fixed by three inverted-triangle cannulated compression screws demonstrated the minimum total deformation, interfragmentary gap, and minimum von Mises stress of implants (1.107 mm, 0.09 mm, and 189.83 MPa, respectively).

INTERPRETATION

Anatomical reduction or positive buttress in femoral neck fractures should be recommended during fracture reduction. The femoral neck system showed weaker biomechanical stability than three inverted-triangle cannulated compression screws in treating Pauwels type-III femoral neck fractures.

Inverse relationship between femoral lateralization and neck-shaft angle is a joint event after intramedullary nailing of per trochanteric fractures

This study explored the relationship between femoral lateralization and femoral neck-shaft angle after intramedullary nail (IM) fixation for per trochanteric fractures. 70 patients (AO/OTA 31A1-2) were investigated. Anteroposterior (AP) and lateral X-ray views pre- and post-operation were recorded. Patients were classified into three groups according to the position of the medial cortex of the head-neck fragment to that of the femoral shaft: being slightly superomedial (positive medial cortex support, PMCS), being smoothly contacted (neutral position, NP) or being displaced laterally (negative medial cortex support, NMCS). Patient demographics, femoral lateralization, and neck-shaft angle were measured and statistically analyzed pre- and post-operation. Functional recovery was evaluated by Harris score 3- and 6- months post-operation. All cases ultimately demonstrated radiographic fracture union. There was a tendency to have an increased neck-shaft angle (valgus alignment) in the PMCS group and increased femoral lateralization in the NP group (p < 0.05). Among those three groups, the change in femoral lateralization and neck-shaft angle was statistically different (p < 0.05). An inverse relationship between femoral lateralization and femoral neck-shaft angle was observed. Femoral lateralization increased correspondingly when the neck-shaft angle continuously decreased from the PMCS group to the NP group and then to the NMCS group, and patients in the PMCS group had better functional recovery than the other two groups (p < 0.05). Femoral lateralization was commonly produced after IM fixation for per trochanteric fractures. The fracture fixed in PMCS mode possesses the slightest change in femoral lateralization while maintaining valgus alignment of the femoral neck-shaft angle and good functional outcome, which is superior to NP or NMCS mode.

Positive medial cortical support versus anatomical reduction for trochanteric hip fractures: Finite element analysis and biomechanical testing

BACKGROUND AND OBJECTIVES

The anatomical reduction (AR) is usually considered the best option for fractures. Nevertheless, in unstable trochanteric hip fractures (UTHF), previous clinical reports found that the positive medial cortical support (PMCS, an over-reduction technique) attained higher mechanical stability, but this challenging clinical finding still needs experimental validation.

METHODS

This study constructed in-silico and biomechanical PMCS and AR models, with the use of the most clinically-representative geometry design of fracture models, the multi-directional design in FE analysis, and the subject-specific (osteoporotic) bone material properties, to make the models better mimic the actual condition in clinical settings. Then multiple performance variables (von-Mises stress, strain, integral axial stiffness, displacement, structural changes, etc.) were assessed to uncover details of integral and regional stability.

RESULTS

Among in-silico comparison, PMCS models showed significantly lower maximum displacement than AR models, and the maximum von Mises stress of implants (MVMS-I) was significantly lower in PMCS models than in AR models (highest MVMS-I in -30°-A3-AR of 1055.80 ± 93.37 MPa). Besides, PMCS models had significantly lower maximum von Mises stress along fracture surfaces (MVMS-F) (highest MVMS-F in 30°-A2-AR of 416.40 ± 38.01 MPa). Among biomechanical testing comparison, PMCS models showed significantly lower axial displacement. Significantly lower change of neck-shaft angle (CNSA) was observed in A2-PMCS models. A fair amount of AR models converted into the obvious negative medial cortical support (NMCS) condition, whereas all PMCS models kept the PMCS condition. The results were also validated through comparison to previous clinical data.

CONCLUSIONS

The PMCS is superior to the AR in the UTHF surgery. The current study opens up the second thought of the role of over-reduction technique in bone surgery.

Nonanatomical reduction of femoral neck fractures in young patients treated with femoral neck system: a retrospective cohort study

PURPOSE

Negative buttress reduction should be avoided in the treatment of femoral neck fractures (FNFs) using conventional fixation. As the femoral neck system (FNS) has been recently developed and utilized widely to treat FNFs, the association of reduction quality with postoperative complications and clinical function has not been clarified. The purpose of this study was to evaluate the clinical effect of nonanatomical reduction in young patients with FNFs treated with FNS.

METHODS

This multicenter, retrospective cohort study included 58 patients with FNFs treated with FNS between September 2019 and December 2021. According to the reduction quality immediately following surgery, patients were classified into positive, anatomical, and negative buttress reduction groups. Postoperative complications were assessed with 12 months of follow-up. The logistic regression model was used to identify risk factors for postoperative complications. The postoperative hip function was assessed using the Harris hip scores (HHS) system.

RESULTS

At a follow-up of 12 months, a total of eight patients (8/58, 13.8%) had postoperative complications in three groups. Compared with the anatomical reduction group, negative buttress reduction was significantly associated with a higher complication rate (OR = 2.99, 95%CI 1.10-8.10, P = 0.03). No significant associations were found between positive buttress reduction and the incidence of postoperative complications (OR = 1.21, 95%CI 0.35-4.14, P = 0.76). The difference was not statistically significant in Harris hip scores.

CONCLUSION

Negative buttress reduction should be avoided in young patients with FNFs treated with FNS.

Biomechanical study of femoral neck system for young patients with nonanatomically reduced femoral neck fractures: a finite element

BACKGROUND

A consensus regarding the optimal approach for treating femoral neck fractures is lacking. We aimed to investigate the biomechanical outcomes of Femoral Neck System (FNS) internal fixation components in the treatment of nonanatomically reduced femoral neck fractures.

METHOD

We constructed two types of femoral neck fractures of the Pauwels classification with angles of 30° and 50°, and three models of anatomic reduction, positive buttress reduction and negative buttress reduction were constructed. Subgroups of 1 to 4 mm were divided according to the distance of displacement in the positive buttress reduction and negative buttress reduction models. The von Mises stress and displacements of the femur and FNS internal fixation components were measured for each fracture group under 2100-N axial loads.

RESULTS

When the Pauwels angle was 30°, the positive 1-mm and 2-mm models had lower FNS stress than the negative buttress model. The positive 3- and 4-mm models showed FNS stress similar to that of the negative buttress model. But the four positive buttress models had similar stresses on the femur as the negative buttress model. When the Pauwels angle was 50°, the four positive buttress models had higher FNS stress than the negative buttress model. Three positive buttress models (2 mm, 3 and 4 mm) resulted in lower stress of the femur than the negative buttress model, though the 1-mm model did not. When the Pauwels angle was 30°, the positive buttress model had a lower displacement of the FNS than the negative buttress model and a similar displacement of the femur with the negative buttress model. When the Pauwels angle was 50°, the positive buttress model had a higher displacement of the FNS and femur than the negative buttress model. Our study also showed that the von Mises stress and displacement of the internal fixation and the femur increased as the fracture angle increased.

CONCLUSION

From the perspective of biomechanics, when the Pauwels angle was 30°, positive buttress was more stable to negative buttress. However, when the Pauwels angle was 50°, this advantage weakens. In our opinion, the clinical efficacy of FNS internal fixation with positive buttress may be related to the fracture angle, neck-shaft angle and alignment in the lateral view. This result needs verification in further clinical studies.

Risk factors for cut-outs in geriatric intertrochanteric fractures with cephalomedullary nailing after obtaining acceptable reduction: a case-control study

BACKGROUND

It is irresponsible if we disregard reduction quality to talk about cut-outs in intertrochanteric fractures (ITF) with internal fixation. The aim of this study is to analyze the risk-factors for cut-outs in geriatric ITF with cephalomedullary nailing after obtaining acceptable reduction.

METHODS

In order to investigate the risk-factors for cut-outs in geriatric ITF after obtaining acceptable reduction, we retrospectively reviewed 367 patients who underwent cephalomedullary nail for ITF in our department between September 2016 and December 2021. Potential variables including demographic data and radiological parameters (namely the fracture type, Singh index, lateral wall fracture, cephalic nail position, Parker's ratio index, tip-apex-distance (TAD), and calcar-referenced TAD (CalTAD)) were collected. Logistic regression analysis was performed to identify the significant risk factors for cut-outs.

RESULTS

One hundred twenty-one patients were suitable for this study. Of the 121 cases, nine cases (7.4%) were observed with cut-out or pending cut-out. We found that Age (adjusted odds ratio (OR) 1.158, 95% confidence interval (CI) 1.016 to 1.318, p = 0.028), lateral wall fracture (adjusted OR 11.07, 95%CI 1.790 to 68.380, p = 0.01), and CalTAD (adjusted OR 1.277, 95%CI 1.005 to 1.622, p = 0.045) were independent risk-factors for cut-outs.

CONCLUSIONS

Age, lateral wall fracture and CalTAD are independent risk-factors for cut-outs in geriatric ITF with cephalomedullary nailing after obtaining acceptable reduction. In order to avoid cut-outs, an optimal CalTAD is necessary even obtaining acceptable reduction, especially in the over-aged patients with lateral wall fracture.

CalTAD is the Key Evaluation Tool for Measurement of Cephalic Fixation Position for Predicting Cut-Out in Geriatric Intertrochanteric Fracture Patients with Internal Fixations after Achieving Acceptable Reduction

Objective

To discover the key evaluation tool of the cephalic fixation position for predicting implant failures in geriatric intertrochanteric fracture (ITF) patients treated with internal fixations after achieving an acceptable reduction.

Methods

We measured the geriatric ITF patients undergoing single-screw cephalomedullary nailing (CMN) fixation surgery after obtaining the acceptable reduction (including anatomical reduction and positive medial cortex support reduction) in our treatment group between September 2016 and March 2020 by using four kinds of cephalic fixation position evaluation tools including Cleveland zone system, Parker’s ratio index, tip–apex distance (TAD), calcar-referenced TAD (CalTAD), and analyzed which were the key evaluation tools for measurement of cephalic fixation position for prediction of implant failures in geriatric ITF patients with internal fixations.

Results

Seventy-four ITF patients treated with single-screw CMN fixation after obtaining the acceptable reduction were enrolled in this study. Of the 74 patients, nine cases were observed with implant failures. There were six cases of cut-out and three of pending cut-out. We found that TAD (odds ratio (OR)=1.149; 95% confidence interval (CI), 1.00–1.32; P=.046) and CalTAD (OR=1.140; 95% CI, 1.00–1.30; P=.037) were risk factors for implant failures by univariate analysis, while only CalTAD (OR=1.200; 95% CI, 1.032–1.395; P=.018) was the independent risk factor for implant failures by multivariate analysis. The Kappa coefficient (κ) of CalTAD was .976 (95% CI, .966–.984) by ICC analysis. The ROC analysis showed that the best cut-off value of CalTAD was 23.76 mm with a sensitivity of 77.8% and specificity of 72.3% (area under the curve, AUC =.775; P = .001).

Conclusions

CalTAD is the key evaluation tool for measurement of cephalic fixation position for predicting implant failures in geriatric ITF patients treated with single-screw CMN after obtaining the acceptable reduction.

Early prediction of implant failures in geriatric intertrochanteric fractures with single-screw cephalomedullary nailing fixation

OBJECTIVE

The implant failures of intertrochanteric fractures (ITF) after single-screw cephalomedullary nailing (CMN) were multifactorially associated with various related factors. However, a comprehensive scoring system for the early prediction of implant failures is still lacking. Thus, this study aims to establish a quantification scoring system (QSS) and verify whether the QSS is reliable for predicting implant failures in geriatric ITF patients.

METHODS

We established the QSS of geriatric ITF with single-screw cephalomedullary nailing within three days after surgery. The QSS included eight points totally at eight parameters, including bone quality, fracture type, reduction quality, and internal fixation placement. Then we retrospectively analyzed seventy-seven ITF (seventy-six patients) with surgical treatment between October 2016 and July 2020 in our hospital to verify whether the QSS scoring is suitable for predicting implant failures in ITF patients.

RESULTS

Implant failures were in fifteen fractures (fifteen patients), including six cases of cut-out, eight of pending cut-out, and one of cut-through. There were three cases with 2 points in QSS, three with 3 points, five with 4 points, four with 5 points in these fifteen fractures. No fractures were with 1 point in QSS, and no implant failures when scoring over 5 points in QSS. Except for QSS scoring, no significant difference was in the collected data by binary logistic regression analysis. QSS scoring was significantly associated with implant failures (Adjusted odds ratio (OR) = 7.312; 95% confidence intervals (CI), 2.561 to 20.871; p < 0.001). In the analysis of Spearman's correlation, there was a strong correlation between QSS scoring and the occurrences of implant failures (RQSS = -0.964, p < 0.001). The ROC result indicated that QSS was reliable in predicting implant failures at the cut-off of 5 points (AUC (the area under the curve) = 0.944; 95% CI, 0.866 to 0.983; p < 0.001).

CONCLUSION

The QSS is a useful early prediction of implant failures in geriatric ITF with cephalomedullary nailing fixation. QSS scoring more than 5 points can effectively reduce the risk of implant failures.

Clinical Outcome and Biomechanical Analysis of Dynamic Hip Screw Combined with Derotation Screw in Treating Displaced Femoral Neck Fractures Based on Different Reduction Qualities in Young Patients (≤65 Years of Age)

Objective

To examine the clinical results and biomechanical mechanism of the dynamic hip screw (DHS) and derotation screw (DS) in the treatment of displaced femoral neck fractures (FNF) based on different reduction qualities in young patients (≤65 years of age).

Methods

All patients with FNF who received closed reduction and internal fixation with DHS+DS from January 2014 to August 2019 were retrospectively analyzed. Data on demographics, surgery, clinical outcomes, and postoperative complications were collected. According to the reduction quality immediately after surgery, all patients were categorized into the positive buttress reduction group (PBRG) and the anatomical reduction group (ARG). The complications and clinical outcomes were compared between the two groups. Meanwhile, the biomechanical mechanism of different reduction qualities was further analyzed with finite element analysis (FEA). The distribution of von Mises stress, the peak stress of internal fixation, and the displacement of the proximal fragment were compared between the two groups.

Results

A total of 68 patients were included in our study. Among them, 31 were divided into the PBRG while 37 were in the ARG. The surgical time and fluoroscopy time were significantly shorter in the PBRG than in the ARG (p < 0.05). The degree of femoral neck shortening and the varus change of the femoral-neck shaft angle were lower in the PBRG compared to the ARG (p < 0.05). The excellent-good rate of the Harris hip score was higher in the PBRG compared to the ARG (83.9% vs. 64.8%). The FEA results demonstrated that the stress of DHS+CS and the downward displacement of the proximal femoral neck fragment were greater in the ARG than in the PBRG.

Conclusion

For displaced FNF with difficulty to achieve reduction, DHS+CS combined with positive buttress reduction was an effective treatment in young patients due to better mechanical support, shorter surgical time, less radiation exposure, and higher excellent-good rate of Harris hip score.

Mapping of Vertical Femoral Neck Fractures in Young Patients Using Advanced 2 and 3-Dimensional Computed Tomography

OBJECTIVE

To better describe the pathoanatomy of young patients' femoral neck fractures with the goal of improving surgeons' decisions for treatment including reduction and fixation.

DESIGN

This is a retrospective study of patient records, plain radiographs, and the modern computed tomography scans to study the pathoanatomy of Pauwels II and III femoral neck fractures (coronal angle >30 degrees) in young adults.

SETTING

One American College of Surgeons Level 1 trauma center.

PATIENTS

All patients 18-49 years of age with a surgically repaired Pauwels' II and III (>30 degrees) femoral neck fracture between 2013 and 2017.

METHODS

Fifty-six adult patients younger than 50 years were identified with a femoral neck fracture in the study period, of whom 30 met study criteria. We evaluated plain radiography and computed tomography data including fracture orientation, characteristics of fracture morphology including size, shape, and dimensions, comminution, displacement, and deformity.

RESULTS

Fracture morphology typically included a wide-based caudal head-neck segment (80%) that ends at a variable location along the medial calcar, sometimes as caudal as the lesser trochanter. Comminution was present in 90% of cases mostly located in the inferior quadrant, but anterior or posterior to the void left by the head-neck's caudal segment. The fractures orientations and deformities were reported by means and ranges.

CONCLUSIONS

We investigated and reported on the pathoanatomy of high-energy femoral neck fractures in young adults with the goal of increasing understanding of the injury and improving surgeons' ability to provide for improved treatment decisions and quality fracture repair.

LEVEL OF EVIDENCE

Diagnostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Prediction Model of Osteonecrosis of the Femoral Head After Femoral Neck Fracture: Machine Learning-Based Development and Validation Study

BACKGROUND

The absolute number of femoral neck fractures (FNFs) is increasing; however, the prediction of traumatic femoral head necrosis remains difficult. Machine learning algorithms have the potential to be superior to traditional prediction methods for the prediction of traumatic femoral head necrosis.

OBJECTIVE

The aim of this study is to use machine learning to construct a model for the analysis of risk factors and prediction of osteonecrosis of the femoral head (ONFH) in patients with FNF after internal fixation.

METHODS

We retrospectively collected preoperative, intraoperative, and postoperative clinical data of patients with FNF in 4 hospitals in Shanghai and followed up the patients for more than 2.5 years. A total of 259 patients with 43 variables were included in the study. The data were randomly divided into a training set (181/259, 69.8%) and a validation set (78/259, 30.1%). External data (n=376) were obtained from a retrospective cohort study of patients with FNF in 3 other hospitals. Least absolute shrinkage and selection operator regression and the support vector machine algorithm were used for variable selection. Logistic regression, random forest, support vector machine, and eXtreme Gradient Boosting (XGBoost) were used to develop the model on the training set. The validation set was used to tune the model hyperparameters to determine the final prediction model, and the external data were used to compare and evaluate the model performance. We compared the accuracy, discrimination, and calibration of the models to identify the best machine learning algorithm for predicting ONFH. Shapley additive explanations and local interpretable model-agnostic explanations were used to determine the interpretability of the black box model.

RESULTS

A total of 11 variables were selected for the models. The XGBoost model performed best on the validation set and external data. The accuracy, sensitivity, and area under the receiver operating characteristic curve of the model on the validation set were 0.987, 0.929, and 0.992, respectively. The accuracy, sensitivity, specificity, and area under the receiver operating characteristic curve of the model on the external data were 0.907, 0.807, 0.935, and 0.933, respectively, and the log-loss was 0.279. The calibration curve demonstrated good agreement between the predicted probability and actual risk. The interpretability of the features and individual predictions were realized using the Shapley additive explanations and local interpretable model-agnostic explanations algorithms. In addition, the XGBoost model was translated into a self-made web-based risk calculator to estimate an individual's probability of ONFH.

CONCLUSIONS

Machine learning performs well in predicting ONFH after internal fixation of FNF. The 6-variable XGBoost model predicted the risk of ONFH well and had good generalization ability on the external data, which can be used for the clinical prediction of ONFH after internal fixation of FNF.

Treatment of Pauwels type III femoral neck fracture with medial femoral neck support screw: a biomechanical and clinical study

A femoral neck fracture is currently one of the most common types of fracture in clinical practice. The incidence continues to increase due to traffic accidents, trauma, and osteoporosis. This research includes a biomechanical study and a clinical retrospective study. In the biomechanical studies, three groups' effects (Control Group: 3CCS, DHS group, and study Group: 3CCS + mFNSS group) were compared by vertical compression tests, torsion tests, and fatigue tests. All the data were collected and analyzed. We subsequently performed a retrospective analysis of 131 patients with femoral neck fractures. The operative time, intraoperative blood loss, quality of postoperative fracture reduction, and follow-up observation of fracture healing, screw retreatment rates and fixation failure rates, as well as femoral head necrosis rates and hip function in two groups with 3CCS and 3CCS + mFNSS were compared. By the biomechanical study, we found that 3CCS + Mfnss group were biomechanically superior to 3CCS group and superior to the DHS group in terms of resistance to torsion. However, it was less effective than the DHS group in compressive strength and fatigue resistance. In terms of clinical application, 3CCS + mFNSS group was found to have lower screw retreatment rates and femoral head necrosis rates, and to have better fracture healing rates than group with 3CCS, indicating that medial support screws can effectively resist the vertical shear forces of fracture ends and promote the stability and healing of fracture ends, as well as to reduce the incidence of postoperative complications.

Clinical observation and finite element analysis of cannulated screw internal fixation in the treatment of femoral neck fracture based on different reduction quality

Objective

Femoral neck fracture is one of the most common bone types. The effect of reduction quality on hip joint function and complications after screw internal fixation is not fully understood. To investigate the clinical efficacy and mechanical mechanism of positive buttress, anatomical reduction, and negative buttress in the treatment of femoral neck fracture after cannulated screw fixation.

Methods

Retrospective analysis of patients with femoral neck fracture treated with three cannulated screws internal fixation in our hospital from January 2013 to December 2018. According to the quality of fracture reduction, the patients were divided into positive buttress group, anatomical reduction group, and negative buttress group. Basic information such as injury mechanism, time from injury to surgery, Garden classification and Pauwels classification was collected, Harris scores were performed at 3 months, 6 months, and 12 months after surgery, and postoperative complications (femoral head necrosis, femoral neck shortening, and femoral neck nonunion) were collected. At the same time, three groups of finite element models with different reduction quality were established for stress analysis, their stress clouds were observed and the average displacement and stress of the three groups of models were compared. P < 0.05 was used to represent a statistically significant difference.

Results

A total of 225 cases of unilateral femoral neck fractures were included and followed up for an average of 4.12 ± 0.69 years. There was no significant difference in age, gender, side, injury mechanism, time from injury to surgery, BMI, Garden classification, Pauwels classification, and follow-up time among the three groups (P > 0.05). However, there was significant difference in Harris score at 6 and 12 months after operation among the three groups (P < 0.05), which was higher in the positive buttress group and anatomical reduction group than in the negative buttress group. In addition, the incidence of osteonecrosis of the femoral head in the negative buttress group (32.2%) was greater than that in the anatomical reduction group (13.4%) and the positive buttress group (5.4%) (P < 0.05). In addition, the incidence of femoral neck nonunion and femoral neck shortening in the negative buttress group was also higher than that in the anatomical reduction positive buttress group (P < 0.05). The finite element results showed that the stress and fracture end displacement in the negative buttress group were greater than those in the positive buttress group (P < 0.05).

Conclusion

Both positive buttress and anatomical reduction in the treatment of femoral neck fracture with cannulated screw internal fixation can obtain better clinical effect and lower postoperative complications. Positive brace support and anatomic reduction can limit the restoration of femoral stress conduction. Therefore, it is not necessary to pursue anatomical reduction too deliberately during surgery, while negative buttress reduction should be avoided.

Effect of Fracture Reduction with Different Medial Cortical Support on Stability After Cephalomedullary Nail Fixation of Unstable Pertrochanteric Fractures: A Biomechanical Analysis

BACKGROUND

This study evaluated the biomechanics of the proximal femoral nail antirotation-II (PFNA-II) in AO/OTA 31A2.2 intertrochanteric fractures based on the fracture reduction quality.

METHODS

Unstable intertrochanteric fractures were created according to the AO classification and repaired by proximal femoral nail antirotation-II (PFNA-II) using one of three medial cortical support groups. The specimens were tested using cyclic axial loading. The following parameters were recorded: force and stiffness at failure, maximum vertical and horizontal displacement, neck-shaft angle, and location and patten of failure.

RESULTS

In the cyclic loading test, the force at failure in the anatomical reduction (AR) group was greater than that of the positive medial cortical support (PMCS) group (984.22 ± 12.63 vs. 936.95 ± 16.78) N (P < 0.05) and negative medial cortical support (NMCS) group (918.04 ± 28.86) N (P < 0.05). The stiffness in the AR group was 4.77 and 31.9% higher than that in the PMCS group (P > 0.05) and NMCS group (P < 0.05). The maximum vertical displacement was the largest in the NMCS group. The maximum horizontal displacement in the NMCS group was 28.6 and 19.1% larger than that in the AR group (P > 0.05) and PMCS group (P < 0.05). The neck-shaft angle in the NMCS group was smaller than that in the anatomic reduction group (P < 0.05) and positive support group (P < 0.05).

CONCLUSION

For the unstable AO/OTA 31A2.2 intertrochanteric fracture, there were significant differences in their mechanical stability among AR, PMCS and NMCS. The NMCS is not recommended during the intraoperative reduction.

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

OBJECTIVE

To explore the mechanical stability of unstable pertrochanteric fractures with proximal femoral nail anti-rotation (PFNA-Ⅱ) fixation under different anteromedial cortical support reduction patterns.

METHODS

A 65-year-old healthy male volunteer with no history of hip or systemic disease was recruited. High-resolution computed tomography images with a slice thickness of 0.67 mm of his right femur were obtained. These images were used to establish three-dimensional (3D) models. The lesser trochanter and lateral femoral wall were cut off to create an AO Foundation/Orthopaedic Trauma Association type 31-A2 unstable pertrochanteric fracture model. PFNA-Ⅱ was used to simulate fixation. Nine different fracture reduction patterns, which included positive-positive, positive-neutral, positive-negative, neutral-positive, neutral-neutral, neutral-negative, negative-positive, negative-neutral, and negative-negative cortical support reductions, were simulated. A load of 700 N was applied to simulate a 70 kg elderly patient standing on one leg. The models were subjected to finite element analysis. The displacement and von Mises stress distributions were analyzed.

RESULTS

The positive-positive cortical support reduction pattern showed minimal stress and the negative-negative reduction pattern showed maximal stress on the intramedullary nail. The stress was mainly concentrated at the junction of the helical blade and the main nail and at the site of the lateral aspect of the insertion point of the nail in the great trochanter. The positive cortical support reduction patterns seemed to have smaller maximum displacements of the entire fragment-implant assembly and relative displacements between the head-neck and shaft fragments. Meanwhile, the negative reduction patterns seemed to have larger displacements.

CONCLUSION

The positive-positive support reduction pattern showed better mechanical stability for unstable pertrochanteric fractures. The negative-negative support reduction pattern was prone to fixation failure and should be avoided during an operation.

The Role of Preoperative Computed Tomography on the Quality of Reduction and Outcomes in Intertrochanteric Fracture: A Controlled Trial

Purpose

The study is aimed at assessing the role of preoperative computerised tomography (CT) examination in the quality of reduction and outcomes in elderly patients with intertrochanteric fracture.

Methods

The elderly patients with an intertrochanteric fracture who were treated with proximal femoral nail antirotation were included. The patients were divided into the CT group and the no-CT group according to the presence of preoperative CT examination. Patients' baseline characteristics, quality of reduction, and function were recorded at follow-up. Functional outcomes were evaluated using the Harris hip scores (HHS).

Results

Totally, the study included 182 patients with intertrochanteric fractures, with 85 in the CT group and 97 in the no-CT group, admitted between January 2018 and June 2019. There was no difference in the quality of reduction, HHS, the fracture healing, or postoperative complications between the CT group and the no-CT group. However, the CT group experienced the shorter mean operative time and blood transfusion, compared to the no-CT group.

Conclusions

The preoperative CT examination seems to be excessive for elderly patients with an intertrochanteric fracture.

Nonanatomical Reduction of Femoral Neck Fractures in Young Patients (≤65 Years Old) with Internal Fixation Using Three Parallel Cannulated Screws

Purpose

The study is aimed at investigating the association between different reduction classifications (anatomic reduction, positive buttress position reduction, and negative buttress position reduction) and two end points (complications and reoperations).

Methods

The study retrospectively analyzed 110 patients undergoing internal fixation with three parallel cannulated screws from January 2012 to January 2019 in Huashan Hospital. Based on the principles of the “Gotfried reduction,” all enrolled patients were divided into three groups: anatomic reduction, positive buttress position reduction, and negative buttress position reduction intraoperatively or immediately after surgery. Clinical characteristics including age, sex, side, Garden classification, Pauwels classification, fracture level, reduction classification, Garden alignment index angles, cortical thickness index (CTI), tip-caput distance (TCD), angle of the inferior screw, and the two ending points (complications and reoperations) were included in the statistical analysis. The Mann-Whitney U-test, the chi-square test, Fisher's exact test, and multiple logistic regression analysis were used in the study.

Results

Of the 110 patients included in our study, the mean ± standard deviation (SD) of age was 51.4 ± 10.4 years; 41 patients showed anatomic reduction, 35 patients showed positive buttress position reduction, and 34 patients showed negative buttress position reduction. For the outcomes, 24 patients (anatomic reduction: 6 [14.6%]; positive buttress position reduction: 5 [14.3%]; negative buttress position reduction: 13 [38.2%]) had complications, while 18 patients (anatomic reduction: 5 [12.2%]; positive buttress position reduction: 3 [8.6%]; negative buttress position reduction: 10 [29.4%]) underwent reoperations after surgery. In the multivariate logistic regression analysis of complications, negative buttress position reduction (negative buttress position reduction vs. anatomic reduction, OR = 4.309, 95%CI = 1.137 to 16.322, and p = 0.032) was found to be correlated with higher risk of complications. The same variable (negative buttress position reduction vs. anatomic reduction, OR = 5.744, 95%CI = 1.177 to 28.042, and p = 0.031) was also identified as risk factor in the multivariate logistic regression analysis of reoperations. However, no significant difference between positive reduction and anatomical reduction was investigated in the analysis of risk factors for complications, not reoperations.

Conclusion

Positive buttress position reduction of femoral neck fractures in young patients showed a similar incidence of complications and reoperations compared with those of anatomic reduction. For irreversible femoral neck fractures, if positive buttress position reduction has been achieved intraoperatively, it is not necessary to pursue anatomical reduction; however, negative reduction needs to be avoided.

Assessing the effect of Gotfried reduction with positive buttress pattern in the young femoral neck fracture

BACKGROUND

Although many available surgical procedures for displaced femoral neck fractures in young patients, there are still many challenges to achieve satisfactory results. The incidence of avascular necrosis and nonunion rates remains relatively high despite the progress in our understanding and surgical technique. The purpose of this study was to evaluate the clinical efficacy of Gotfried reduction and cannulated screw fixation in the treatment of femoral neck fracture for young adults.

METHODS

A retrospective analysis was made on 67 cases from May 2013 to March 2019. They were divided into three groups according to the first postoperative anteroposterior view of hip X-ray: Anatomic reduction (group A), Gotfried positive buttress reduction (group B), and Gotfried negative buttress reduction (group C). The incidence of avascular osteonecrosis of the femoral head (AVN) and the Harris scores of hip joints were compared in three groups at the last follow-up.

RESULTS

The mean follow-up period after surgery was 22.5 ± 11.3 (range, 11-34) months. There were 21 cases (mean age, 49.7 ± 11.6) in group A, 24 cases (mean age, 48.6 ± 11.3) in group B, 22 cases (mean age, 48.3 ± 12.4) in group C. No significant difference in general preoperative demographics (P > 0.05). The incidence of avascular necrosis of femoral head in group A, B, and C was 19.05%, 20.83%, and 22.73%, respectively, showing no significant difference between groups (P = 0.156). The mean Harris hip scores at the final follow-up for groups A (85.6 ± 6.7) and B (84.5 ± 6.2) were significantly higher than group C (74.3 ± 8.3), and the difference was statistically significant (P = 0.043). The incidence of femoral neck shortening in group A and group B was significantly lower than that in group C in postoperative 1 year, and the difference was statistically significant (P < 0.05).

CONCLUSIONS

Gotfried positive buttress reduction and fixation for femoral neck fracture may lead to similar clinical results with anatomic reduction, but much better than Gotfried negative buttress reduction. For the patients of femoral neck fracture with severe displacement and difficulty reduction, it is not necessary to pursue anatomical reduction. Achieving positive valgus reduction can also obtain satisfactory clinical results, and should try to avoid negative buttress.

A quantitative biomechanical study of positive buttress techniques for femoral neck fractures: a finite element analysis

Background:

Refractory femoral neck fractures cannot be anatomically reduced by closed traction reduction which may affect fracture healing. We evaluated the biomechanical effects of positive, negative, and anatomic reduction of various degrees of displacement in Pauwels I femoral neck fractures by a finite element analysis.

Methods:

Five reduction models of Pauwels type I femoral neck fracture were established using the Mimics 17.0 (Materialize, Leuven, Belgia) and Hypermesh 12.0 (Altair Engineering, Troy, MI, USA). According to the degree of fracture displacement, there were three models of positive support, an anatomic reduction model, and a negative 2 mm reduction model. Finite element analysis was conducted using the ABAQUS 6.9 software (Simulia, Suresnes, France). The von Mises stress distribution and the stress peak of internal fixation in different models, the displacement between fracture blocks, and the principal strain of the femoral neck cancellous bone model were recorded under the axial stress of 2100 N.

Results:

The peak von Mises stress on screw of each model was located at the thread of the screw tip. The peak von Mises stress was the lowest at the tip of the anatomic reduction model screw (261.2 MPa). In the positive 4 mm model, the von Mises stress peak was the highest (916.1 MPa). The anatomic reduction model showed the minimum displacement (0.388 mm) between fracture blocks. The maximum displacement was noted in the positive 4 mm model (0.838 mm). The displacement in the positive 3 mm model (0.721 mm) was smaller than that in the negative 2 mm model (0.786 mm). Among the five models, the strain area of the femoral neck cancellous bone was mainly concentrated around the screw hole, and the area around the screw hole could be easily cut.

Conclusions:

Compared with negative buttress for femoral neck fracture, positive buttress can provide better biomechanical stability. In Pauwel type I fracture of femoral neck, the range of positive buttress should be controlled below 3 mm as far as possible.

Gotfried positive reduction promotes the repair of femoral neck fracture potentially via enhancing osteogenesis and angiogenesis

The aim of this study was to investigate the effect of Gotfried positive reduction (GPR) on repair of femoral neck fracture in rabbits and its underlying mechanisms. Male New Zealand white rabbits were employed to establish the model of femoral neck fracture. All the rabbits were randomly divided into four groups: control, open accurate reduction (OR), closed Gotfried negative support reduction (CR-N) and closed Gotfried positive support reduction (CR-P). At the 8th and 12th week after surgery, the anteroposterior and lateral radiographs of their hip joints were taken by X-ray, and local hemodynamics of their hip joints was detected by ultrasound. Histological examination was evaluated by HE staining and bone biological strength test was measured by testing machine, which was performed to study the repair of femoral neck fracture. Osteogenesis and angiogenesis-related proteins were measured by western blot in bone tissues and synovial tissues. The results revealed that the fracture healing intensity and blood supply in CR-P were better than those in CR-N and much more excellent than those in OR. In addition, the content of bone morphogenetic protein2 (BMP2), platelet derived growth factor (PDGF) and ocsteocalcin was higher in CR-P group than in CR-N, while lower in CR-P than OR. Furthermore, the expression of BMP2, COL-2 and angiopoietin (ANGPT) was upregulated in CR-P compared to CR-N and OR. Taken together, our results indicated that GPR was able to promote the repair of femoral neck fracture via enhancing osteogenesis and angiogenesis, which is valuable to us and shows good application prospect in bone tissue repair.

Comparison of Baumgaertner and Chang reduction quality criteria for the assessment of trochanteric fractures

Objectives

Different criteria for assessing the reduction quality of trochanteric fractures have been reported. The Baumgaertner reduction quality criteria (BRQC) are relatively common and the Chang reduction quality criteria (CRQC) are relatively new. The objectives of the current study were to compare the reliability of the BRQC and CRQC in predicting mechanical complications and to investigate the clinical implications of the CRQC.

Methods

A total of 168 patients were assessed in a retrospective observational study. Clinical information including age, sex, fracture side, American Society of Anesthesiologists (ASA) classification, tip-apex distance (TAD), fracture classification, reduction quality, blade position, BRQC, CRQC, bone quality, and the occurrence of mechanical complications were used in the statistical analysis.

Results

A total of 127 patients were included in the full analysis, and mechanical complications were observed in 26 patients. The TAD, blade position, BRQC and CRQC were significantly associated with mechanical complications in the univariate analysis. Only the TAD (p = 0.025) and the CRQC (p < 0.001) showed significant results in the multivariate analysis. In the comparison of the receiver operating characteristic curves, the CRQC also performed better than the BRQC.

Conclusion

The CRQC are reliable in predicting mechanical complications and are more reliable than the BRQC. Future studies could use the CRQC to assess fracture reduction quality. Intraoperatively, the surgeon should refer to the CRQC to achieve good reduction in trochanteric fractures.

Cite this article: Bone Joint Res 2019;8:502–508.

[Research progress on anteromedial cortical positive support reduction in treatment of intertrochanteric fracture]

Objective

To introduce the reduction concept of anteromedial cortical support in the treatment of intertrochanteric fracture, summarize the history, characteristics, biomechanics, and clinical applications, discuss the unsolved problems and prospect the future directions.

Methods

Relevant domestic and foreign studies on cortical support reduction of intertrochanteric fracture in recent years were reviewed. Conclusions were drawn combined with clinical experience.

Results

The positive cortical supportive reduction of intertrochanteric fracture, as a stable non-anatomical fracture reduction technique, has dual effects on mechanical buttress and biological bone healing. It does not increase the difficulty of doctors' surgical procedure. For patients, it decreases the loss of femoral neck length, the loss of neck-shaft angle, the incidence rate of coxa vara, and maintains stable mechanical structure of the pelvis. It also shows a lower rate of instrument-related complications, and higher limb function scores. The mechanical stability of medial cortex apposition is more important than that of anterior cortex. For the best stability of the fracture, both sides should get positive support reduction pattern.

Conclusion

Anteromedial cortical support reduction can improve the postoperative stability of intertrochanteric fracture, enable better imaging and functional prognosis. As a kind of non-anatomic form of functional reduction, it can be used as a suboptimal choice secondary to anatomic reduction.

Inferior calcar buttress reduction pattern for displaced femoral neck fractures in young adults: a preliminary report and an effective alternative

Background

Fracture reduction quality is of paramount importance for osteosynthesis. The aim of this study was to report the outcome of an inferior cortical buttress non-anatomic reduction pattern and internal fixation for displaced femoral neck fractures (Garden types III and IV) in young adults.

Methods

A retrospective analysis of 46 displaced femoral neck fractures was performed, which were treated by closed reduction and internal fixation with parallel cannulated screws. There were 20 males and 26 females, with an average age of 50.3 years (19–60). According to the inferior cortical reduction quality seen in recorded intraoperative fluoroscopy, the patients were divided into two groups. Group I (n = 30) was anatomic cortical apposition as the two inferior cortices were smoothly contacted, and group II (n = 16) was buttress cortical apposition as the two inferior cortices were located in positive support contact (Gotfried reduction pattern). With a mean follow-up of 22.0 months, femoral neck length, neck–shaft angle, and clinical outcomes were compared.

Results

Thirty-nine patients (84.8%) achieved uneventful fracture union. Complications occurred in seven patients, six in group I (20%) and one in group II (6.3%), including displacement to varus, neck shortening, early fixation failure, nonunion, and avascular necrosis of the femoral head. No significant difference existed in the complication rate between the two groups (p = 0.216). Four patients (13.3%) in group I were converted to prosthetic replacement, but none in group II.

Conclusions

For closed reduction and fixation of displaced femoral neck fractures in young adults, an inferior cortical buttress reduction pattern, though non-anatomic, can produce sustainable fracture stability and predictable clinical outcomes.

[Effectiveness analysis of surgical treatment of ipsilateral femoral neck fracture and subtrochanteric fracture]

Objective

To discuss the effectiveness of intramedullary nail fixation with selective cable wiring in the treatment of ipsilateral femoral neck fracture and subtrochanteric fracture.

Methods

Between June 2012 and December 2015, a total of 19 patients with ipsilateral femoral neck fracture and subtrochanteric fracture underwent closed reduction of femoral neck fracture and intramedullary nail fixation combined with selective cable wiring. There were 5 males and 14 females with a median age of 52 years (range, 35-77 years). The cause of injury included traffic accident injury in 17 cases and falling injury in 2 cases. According to Garden classification for femoral neck fractures, 7 cases were rated as type Ⅱ, 8 as type Ⅲ, and 4 as type Ⅳ. Femoral subtrochanteric fractures were classified by Seinsheimer classification, with 9 cases as type Ⅱ, 5 as type Ⅲ, 3 as type Ⅳ, and 2 as type V. The interval from injury to operation ranged from 2 to 7 days with an average of 3.7 days.

Results

The operation time was 58-125 minutes (mean, 82.4 minutes) and the intraoperative blood loss was 225-725 mL (mean, 289.5 mL). All incisions achieved healing by first intention and no early complication such as infection was observed. All patients were followed up 12-18 months (mean, 13.9 months). At 1 month after operation, the tip apex distance was 9-23 mm (mean, 15.2 mm). All patients achieved bone union with the healing time of 18-42 weeks (mean, 27.4 weeks). One case of hip varus and femoral neck re-displacement (femoral neck shaft angle was 122°) occurred at 3 months after operation, which achieved bone union at 42 weeks after operation. Five patients complained of postoperative pain with the visual analogue scale (VAS) score of 1-3 (mean, 1.8), which did not influence normal life. A total of 16 patients recovered preoperative hip function. During follow-up, no fracture nonunion, femoral head necrosis, implant failure, screw cut-out, and loosening of cable wiring was observed. The Harris hip score (HSS) was 72-92 (mean, 82.8) at last follow-up and 15 patients (78.9%) achieved good hip function.

Conclusion

Intramedullary nail fixation combined with selective cable wiring was effective in the treatment of ipsilateral femoral neck fracture and subtrochanteric fracture.

Intramedullary Fixation With Minimally Invasive Clamp-Assisted Reduction for the Treatment of Ipsilateral Femoral Neck and Subtrochanteric Fractures: A Technical Trick

The purpose of this study is to describe a surgical technique for intramedullary fixation and minimally invasive clamp-assisted reduction with selective cerclage wiring for the management of combined ipsilateral femoral neck and subtrochanteric fractures and to present the clinical outcomes in 17 patients after treatment using this technique.

Fracture reduction with positive medial cortical support: a key element in stability reconstruction for the unstable pertrochanteric hip fractures

PURPOSE

To introduce the concept of fracture reduction with positive medial cortical support and its clinical and radiological correlation in geriatric unstable pertrochanteric fractures.

METHODS

A retrospective analysis of 127 patients (32 men and 95 women, with mean age 78.7 years) with AO/OTA 31A2.2 and 2.3 hip fractures treated with cephalomedullary nail (PFNA-II or Gamma-3) between July 2010 and June 2013 was performed. They were classified into three groups according the grade of medial cortical support in postoperative fracture reduction (positive, neutral, and negative). The positive cortex support was defined that the medial cortex of the head-neck fragment displaced and located a little bit superomedially to the medial cortex of the shaft. If the neck cortex is located laterally to the shaft, it is negative with no cortical buttress, and if the two cortices contact smoothly, it is in neutral position. The demographic baseline, postoperative radiographic femoral neck-shaft angle and neck length, rehabilitation progress and functional recovery scores of each group were recorded and compared.

RESULTS

There were 89 cases (70 %) in positive, 26 in neutral, and 12 in negative support. No statistical differences were found between the three groups among patient age, sex ratio, prefracture score of activity of daily living, walking ability score, ASA physical risk score, number of medical comorbidities, osteoporosis Singh index, fracture reduction quality (Garden alignments), and the position of lag screw or helical blade in femoral head (TAD). In follow-up, patients in positive medial cortical support reduction group had the least loss in neck-shaft angle and neck length, and got ground-walking much earlier than negative reduction group, with good functional outcomes and less hip-thigh pain presence.

CONCLUSION

Fracture reduction with nonanatomic positive medial cortical support allows limited sliding of the head-neck fragment to contact with the femur shaft and achieve secondary stability, providing a good mechanical environment for fracture healing.