Proximal Femur Bionic Nail (PFBN): A Panacea for Unstable Intertrochanteric Femur Fracture

With the aging population,intertrochanteric femur fracture in the elderly has become one of the most serious public health issues and a hot topic of research in trauma orthopedics.Due to the limitations of internal fixation techniques and the insufficient mechanical design of nails,the occurrence of complications delays patient recovery after surgical treatment.Design of a proximal femur bionic nail(PFBN)based on Zhang’s N triangle theory provides triangular supporting fixation,which dramatically decreases the occurrence of complications and has been widely used for clinical treatment of unstable intertrochanteric femur fracture worldwide.In this work,we developed an equivalent biomechanical model to analyze improvement in bone remodeling of unstable intertrochanteric femur fracture through PFBN use.The results show that compared with proximal femoral nail antirotation(PFNA)and InterTan,PFBN can dramatically decrease the maximum strain in the proximal femur.Based on Frost’s mechanostat theory,the local mechanical environment in the proximal femur can be regulated into the medium overload region by using a PFBN,which may render the proximal femur in a state of physiological overload,favoring post-operative recovery of intertrochanteric femur fracture in the elderly.This work shows that PFBN may constitute a panacea for unstable intertrochanteric femur fracture and provides insights into improving methods of internal fixation.

Numerical Simulation of Bone Remodeling Coupling the Damage Repair Process in Human Proximal Femur

Microdamage is produced in bone tissue under the long-termeffects of physiological loading,as well as age,disease and other factors.Bone remodeling can repair microdamage,otherwise this damage will undermine bone quality and even lead to fractures.In this paper,the damage variable was introduced into the remodeling algorithm.The new remodeling algorithm contains a quadratic term that can simulate reduction in bone density after large numbers of loading cycles.The model was applied in conjunction with the 3Dfinite elementmethod(FEM)to the remodeling of the proximal femur.The results showed that the initial accumulation of fatigue damage led to an increase in density but when the damage reached a certain level,the bone density decreased rapidly until the femur failed.With the accumulation of damage,bone remodeling was coupled with fatigue damage to maintain the function of bone.When the accumulation of damage reached a certain level,bone remodeling failed to repair the accumulated fatigue damage in time,and continued cyclic loading significantly weakened the loadbearing capacity of the bone.The new mathematical model not only predicts fatigue life,but also helps to further understand the compromise between damage repair and damage accumulation,which is of great significance for the prevention and treatment of clinical bone diseases.

Bone mineral density in fracture neck of femur patients:What's the significance?

BACKGROUND The National Institute for Health and Care Excellence(NICE)guidelines have advised further research is required into investigating the added prognostic value of bone mineral density(BMD)in the assessment of fracture risk with the Fracture Risk Assessment Tool(FRAX)score.AIM To investigate the significance of BMD in fracture neck of femur patients and compare it to the outcome of the FRAX score.METHODS Inclusion criteria for this study were all patients who underwent dual-energy Xray absorptiometry(DXA)scan following fracture neck of femur between 2015 and 2017.Analysis of BMD,FRAX scores and patient demographic data was undertaken.RESULTS A total of 69 patients were included in the study,mean age 74.1 years.There was no significant difference between mean BMD of the femoral neck in males(0.65)as compared to females(0.61)(P=0.364).Analyses showed no significant correlation between BMD and menopause age(rs=-0.28,P=0.090).A significant difference was seen of the femoral neck BMD between the different fracture pattern types(P=0.026).A stronger correlation was observed between BMD of femoral neck and FRAX major score(rs=-0.64,P<0.001)than with BMD of lumbar spine and FRAX major score(rs=-0.37,P=0.003).CONCLUSION This study demonstrated that BMD of the femoral neck measured by DXA scan is of added prognostic value when assessing patients for risk of fracture neck of femur in combination with the FRAX predictive scoring system.

Management bone loss of the proximal femur in revision hip arthroplasty: Update on reconstructive options

The number of revision total hip arthroplasties is expected to rise as the indications for arthroplasty will expand due to the aging population. The prevalence of extensive proximal femoral bone loss is expected to increase subsequently. The etiology of bone loss from the proximal femur after total hip arthroplasty is multifactorial. Stress shielding, massive osteolysis, extensive loosening and history of multiple surgeries consist the most common etiologies. Reconstruction of extensive bone loss of the proximal femur during a revision hip arthroplasty is a major challenge for even the most experienced orthopaedic surgeon. The amount of femoral bone loss and the bone quality of the remaining metaphyseal and diaphyseal bone dictate the selection of appropriate reconstructive option. These include the use of impaction allografting, distal press-fit fixation, allograft-prosthesis composites and tumor megaprostheses. This review article is a concise review of the current literature and provides an algorithmic approachfor reconstruction of different types of proximal femoral bone defects.

Dose of alendronate directly increases trabeculae expansivity without altering bone volume in rat femurs

AIM To evaluate the effects of sodium alendronate on bone repair in fractures created in appendicular bones. METHODS Wistar rats(n = 36) were allocated into three distinct groups: group C(control), group B1(received 1 mg/kg of alendronate), and group B2(received 3 mg/kg of alendronate). The rats underwent femoral transversal linear fracture surgery using stable internal fixation with a 2.0 mm plate and screw system. Each animal randomly received intraperitoneal applications of sodium alendronate at a dose corresponding to group B1 or B2 three times a week, while the control group received a 0.9% saline solution. Drug administration was performed until euthanasia at 45 d. The femurs were removed and each surgical piece was sent for radiographic, tomographic and microtomographic analysis. Data were submitted to descriptive and inferential statistical analysis(95% confidence interval).RESULTS Quantitative evaluations of bone neoformation did not show differences among the groups in the radiographic(P = 0.341), microtomographic(P = 0.581) and tomographic evaluations(P = 0.171). In the qualitative microtomographic analysis, a smaller distance was observed between the internal bone trabeculae in the groups that used alendronate(P = 0.05). On the other hand, group B2 had a higher amount of bone trabeculae per unit length when compared to the other groups(P = 0.04).CONCLUSION It is likely that the use of alendronate did not have a direct influence on the amount of bone neoformation, however it did influence the bone quality in a dosedependent manner, ultimately affecting the distance and quantity of the trabeculae.

Giant Aneurysmal Bone Cyst of the Right Femur about a Case

Aneurysmal bone cyst (ABC) is a rare bone tumor accounting for 1% - 4% of benign bone tumors. Its etiopathogenesis remains unknown. The main site is the metaphysis of the long bones. ABC occurs almost exclusively in young people, with a slight female predominance. We report an exceptional case of ABC of the femur with involvement of the right hip in a 16-year-old girl in the Medical Imaging Department of Pr Bocar Sidy Sall Hospital of Kati (Mali). We will discuss the clinical and radiological aspects of this pathology. Observation: Mrs N C., aged 16, was referred to the orthopaedic-traumatology department for an X-ray of the right thigh, indicated as having a large, disabling thigh. Clinical examination revealed a large thigh measuring 890 mm in circumference, compared with 300 mm on the contralateral side. Radiographically, the femur showed a blown appearance, with the cortex thinned and broken in places. Exceptionally, the lesion affected the entire femur. On CT scan, we found a voluminous fluid collection occupying the entire right femur, including the right femoral head and homolateral ischium. The cortex was interrupted in places, and the adjacent soft tissues were thinned or laminated, but not infiltrated. Histology revealed haemorrhagic and inflammatory elements compatible with the diagnosis of ABC. Conclusion: ABC is a tumor entity that is often difficult to diagnose. Medical imaging, topographical distribution and histology form an indissociable whole to establish a diagnosis of certainty.

The Effect of Bone Loss Pattern on the Structural Capacity of the Proximal Femur

The effect of age-related bone loss on the structural capacity of the proximal femur were investigated by Finite Element Analysis (FEA). Four bone loss patterns were considered. These were "uniform cortical bone loss", "neck cortical bone loss", "intertrochanteric cortical bone loss" and "uniform trabecular bone loss". The results show that the two "non-uniform cortical bone loss" patterns are more dangerous than the "uniform cortical bone loss" pattern, and that the cortical bone loss in intertrochanteric region is associated with a greater reduction in cortical failure load than the cortical bone loss in the femoral neck. The trabecular bone loss causes a limited decrease in both cortical failure and trabecular failure loads. This research should be helpful to the clinical assessment of femur fracture risk due to age-related bone loss.

Clinical and functional comparison of endoprosthetic replacement with intramedullary nailing for treating proximal femur metastasis

Objective： To evaluate the clinical and functional outcomes of modular endoprosthetic replacement （EPR） compared to proximal femur intramedullary nailing （IMN） for the treatment of proximal femur metastases. Methods： We retrospectively studied the records of patients with proximal femur metastatic lesions treated with surgical stabilization between January 2007 and December 2014 in terms of operation time, blood loss, postoperative score, soreness, Karnofsky performance score （KPS） and survival time. Results： There were 34 patients treated with surgical stabilization. The mean follow-up period was 12.1~8.6 months （range： 10-47 months）. Thirteen were treated with EPR and 21 were stabilized with IMN （20 males, 14 females; mean age： 68.7 years）. The median survival time was 11.0 months for both groups （P=0.147）. The operation time, blood loss and Harris score of IMN group were lower than those of EPR group （P=0.001, P=0.001, P=0.002, respectively）. Conclusions： Both EPR and IMN for treating proximal femur metastasis achieved effective clinical outcomes. Therefore, the suitable surgical methods depended on the general conditions and medical requirements of patients, as well as the technical advantages of the doctor.

Clinical and functional comparison of dynamic hip screws and intramedullary nails for treating proximal femur metastases in older individuals

Objective:To compare the outcomes of dynamic hip screws(DHS)and intramedullary nailing(IMN)in the treatment of extra-capsular metastatic carcinoma of the proximal femur.Methods:A retrospective case analysis method was used to examine data of patients with proximal metastatic cancer of the femur who were treated with internal fixation in Department of Orthopaedics,Beijing Friendship Hospital,from January 2007 to December 2018.Blood loss,postoperative pain,functional score,length of stay,and survival rates were compared,and postoperative complications were assessed.Results:Complete follow-up data were available for 33 patients.The mean follow-up period was 12.2±3.6(range:9-32)months and the average age was 72.3±4.7(range:59-83)years old.There were 20 females and 13 males.Twenty-three patients had undergone IMN and 10 DHS,according to bone defects and the patient’s overall condition.The median survival time was 10 months in the IMN group and 11 months in the DHS group.Duration of surgery(t=-7.366,P<0.001)and length of hospital stay(t=-3.509,P<0.001)differed significantly between the two groups.There was one case of breakage of internal fixation in the IMN group.Conclusions:There was no significant difference between DHS and IMN in terms of surgical efficacy.IMN and DHS were different in terms of surgical time and hospital stay.However,due to the limited number of cases in this study,multi-factor analysis has not been performed and needs to be further verified in future analysis.When developing a surgical plan,it is recommended to consider the patient’s condition and the surgeon’s experience.

Low-grade central osteosarcoma of distal femur, resembling fibrous dysplasia

We report a case of a 32 year-old male, admitted for a lytic lesion of the distal femur. One month after the first X-ray, clinical and imaging deterioration was evident. Open biopsy revealed fibrous dysplasia. Three months later, the lytic lesion had spread to the whole distal third of the femur reaching the articular cartilage. The malignant clinical and imaging features necessitated excision of the lesion and reconstruction with a custom-made total knee arthroplasty. Intraoperatively, no obvious soft tissue infiltration was evident. Nevertheless, an excision of the distal 15.5 cm of the femur including 3.0 cm of the surrounding muscles was finally performed. The histological examination of the excised specimen revealed central low-grade osteosarcoma. Based on the morphological features of the excised tumor, allied to the clinical findings, the diagnosis of low-grade central osteosarcoma was finally made although characters of a fibrous dysplasia were apparent. Central low-grade osteosarcoma is a rare, well-differentiated sub-type of osteosarcoma, with clinical, imaging, and histological features similar to benign tumours. Thus, initial misdiagnosis is usual with the condition commonly mistaken for fibrous dysplasia. Central low-grade osteosarcoma is usually treated with surgery alone, with rare cases of distal metastases. However, regional recurrence is quite frequent after close margin excision.

Comparison of Concentrations of Lead and Cadmium in Various Parts of The Femur Head in Patients after Arthroplasty of The Hip Joint in Northwest Poland

Abstract Objective To determine the concentrations of lead （Pb） and cadmium （Cd） in three kinds of materials （cartilage, cortical bone, and cancellous bone） of the femur head obtained from patients in the process of operation. Methods Concentrations of Pb and Cd were determined in selected parts of the femur head of 30 patients after total hip arthroplasty, using ICP-AES （atomic absorption spectrophotometry）. Results Pb contained the highest concentration in cortical bone, while Cd did so in cancellous bone. There were statistically significant differences in the concentrations of both elements between the cartilage and cortical bone, and also differences in the concentration of Pb between the cartilage and cancellous bone. There were no significant differences in the concentrations of Pb or Cd between cortical and cancellous bone. Conclusion Comparative studies on toxic metals should take into account both analogous bones and their fragments, as even if they come from the same kind of bones （e.g. femur head）, clear differences exist in concentrations of heavy metals related to the sampling site and type of tissue （cartilage, cortical bone, and cancellous bone）.

A Femur-Implant Model for the Prediction of Bone Remodeling Behavior Induced by Cementless Stem

Bone remodeling simulation is an effective tool for the prediction of long-term effect of implant on the bone tissue, as well as the selection of an appropriate implant in terms of architecture and material. In this paper, a finite element model of proximal femur was developed to simulate the structures of internal trabecular and cortical bones by incorporating quantitative bone functional adaptation theory with finite element analysis. Cementless stems made of titanium, two types of Functionally Graded Material （FGM） and flexible ＇iso-elastic＇ material as comparison were implanted in the structure of proximal femur respectively to simulate the bone remodeling behaviors of host bone. The distributions of bone density, von Mises stress, and interface shear stress were obtained. All the prosthetic stems had effects on the bone remodeling behaviors of proximal femur, but the degrees of stress shielding were different. The amount of bone loss caused by titanium implant was in agreement with the clinical obser- vation. The FGM stems caused less bone loss than that of the titanium stem, in which FGM I stem （titanium richer at the top to more HAP/Col towards the bottom） could relieve stress shielding effectively, and the interface shear stresses were more evenly distributed in the model with FGM 1 stem in comparison with those in the models with FGM II （titanium and bioglass） and titanium stems. The numerical simulations in the present study provided theoretical basis for FGM as an appropriate material of femoral implant from a biomechanical point of view. The next steps are to fabricate FGM stern and to conduct animal experiments to investigate the effects of FGM stem on the remodeling behaviors using animal model.

Indication and surgical approach for reconstruction with endoprosthesis in bone-associated soft tissue sarcomas:Appropriate case management is vital

It is important for surgeons performing sarcoma surgery to know that bone resection and tumor prosthesis applications in soft tissue sarcomas(STS)have unique features in terms of indication,surgical approach and follow-up,in terms of the management of these cases.Some STS are associated with bone and major neurovascular structures.Bone-associated STS are generally relatively large and relatively deep-seated.Additionally,the tendency for metastasis is high.In some cases,the decision about which structures to resect is difficult.These cases are often accompanied by poor oncological and surgical outcomes.Management of cases should be done by a multidisciplinary team in advanced centers specialized in this field.The surgical team must have sufficient knowledge and experience in the field of limb-sparing surgery.Preoperative evaluation and especially good planning of bone and soft tissue reconstruction are vital.

Long-term disease-free survival after surgical resection for multiple bone metastases from rectal cancer

Bone metastasis of primary colorectal cancer is uncommon.When it occurs,it is usually a late manifestation of disease and is indicative of poor prognosis.We describe a patient with multiple metachronous bone metastases from lower rectal cancer who was successfully treated with multimodal treatment including surgical resections and has shown 32 mo disease-free survival.Surgical resection of metastatic bone lesion(s)from colorectal cancer may be a good treatment option in selected patients.

Autologous grafts of double-strut fibular cortical bone plate to treat the fractures and defects of distal femur： a case report and review of literature

We reported a 23-year-old man who was involved in a high-speed motorcycle accident. He sustained a closed fracture at the right distal femur. The primary fracture happened on February 2008. He underwent open reduction and internal fixation with cloverleaf plate. And one hundred days after the surgery, the proximal screws were pulled-out, but the bone union was not achieved. Treatment consisted of exchanging the cloverleaf plate with a locking compression plate and using an auto-iliac bone graft to fill the nonunion gap. In July 2009, the patient had a sharp pain in the right lower limb. The X-ray revealed that the plate implanted last year was broken, causing a nonunion at the fracture site. Immediately the plate and screws were removed and an intramedullary nail was inserted reversely from the distal femur as well as a 7 cm long bone from the right fibula was extracted and longitudinally split into two pieces to construct cortical bone plates. Then we placed them laterally and medially to fracture site, drilled two holes respectively, and fastened them with suture. We carried on auto-iliac bone grafting with the nonunion bone grafts. The follow-up at 15 months after operation showed that the treatment was successful, X-ray confirmed that there was no rotation and no angular or short deformity. We briefly reviewed the literature regarding such an unusual presentation and discussed in details the possible etiology and the advantages of autologous double-strut fibular grafts to cope with such an intractable situation.

Solitary Bone Cyst of the Proximal Humerus with a Concomitant Stiff Shoulder Treated with both Arthroscopic Capsular Release and Arthroscope-Assisted Resection of the Bone Cyst: A Case Report

Solitary bone cysts are benign bone lesions that usually occur in the humerus, calcaneus, and femur of children and adolescents. When present in adults, they are usually diagnosed as incidental findings. In this report, we present an adult case of a solitary bone cyst of the proximal humerus with concomitant refractory stiff shoulder treated with both arthroscopic capsular release and arthroscope-assisted resection of the bone cyst. A 73-year-old woman was referred with a complaint of persistent left shoulder pain and limited range of motion. Magnetic resonance imaging showed an approximately 4.5-cm long diameter cystic bone lesion from the humeral neck to the shaft. At first, arthroscopic synovectomy and pan-capsular release were performed. Next, two 1-cm skin incisions and 8-mm drill holes into the lateral wall of the cyst were created with fluoroscopic guidance. After insertion of the arthroscope through the holes, the white membranous cyst wall was resected with a shaver until bone marrow was observed. Finally, an 8-mm cannulated hydroxyapatite pin was inserted. This is a simple technique that allows direct visualization and complete resection of the cyst wall with two small incisions. Such a technique may be superior to conventional open procedures or those under image guidance.

Bone mineral density in lifelong trained male football players compared with young and elderly untrained men

Purpose: The purpose of the present controlled cross-sectional study was to investigate proximal femur and whole-body bone mineral density(BMD), as well as bone turnover profile, in lifelong trained elderly male football players and young elite football players compared with untrained age-matched men.Methods: One hundred and forty healthy, non-smoking men participated in the study, including lifelong trained football players(FTE, n = 35)aged 65—80 years, elite football players(FTY, n = 35) aged 18—30 years, as well as untrained age-matched elderly(UE, n = 35) and young(UY,n = 35) men. All participants underwent a regional dual-energy X-ray Absorptiometry(DXA) scan of the proximal femur and a whole-body DXA scan to determine BMD. From a resting blood sample, the bone turnover markers(BTMs) osteocalcin, carboxy-terminal type-1 collagen crosslinks(CTX-1), procollagen type-1 amino-terminal propeptide(P1NP), and sclerostin were measured.Results: FTE had 7.3%—12.9% higher(p < 0.05) BMD of the femoral neck, wards, shaft, and total proximal femur in both legs compared to UE,and 9.3%—9.7% higher(p < 0.05) BMD in femoral trochanter in both legs compared to UY. FTY had 24.3%—37.4% higher(p < 0.001) BMD in all femoral regions and total proximal femur in both legs compared to UY. The whole-body DXA scan confirmed these results, with FTE showing similar whole-body BMD and 7.9% higher(p < 0.05) leg BMD compared to UY, and with FTY having 9.6% higher(p < 0.001) wholebody BMD and 18.2% higher(p < 0.001) leg BMD compared to UY. The plasma concentration of osteocalcin, CTX-1, and P1NP were 29%,53%, and 52% higher(p < 0.01), respectively, in FTY compared to UY.Conclusion: BMD of the proximal femur and whole-body BMD are markedly higher in lifelong trained male football players aged 65—80 years and young elite football players aged 18—30 years compared to age-matched untrained men. Elderly football players even show higher BMD in femoral trochanter and leg BMD than untrained young despite an age difference of 47 years.

Anybody仿真太极不同步法时股骨及下肢骨主要关节的应力特征

背景:Anybody骨肌建模系统,使用数学建模技术模拟人体骨骼、肌肉和环境的关系,可对人体的逆向动力学进行研究,得出下肢关节力等指标。目的:分析练习太极拳动作时下肢骨主要关节的应力分布规律,为其科学训练和锻炼价值提供依据。方法:在北京体育大学武术学院选取8名太极拳健将级运动员进行7组步法动作和右腿股骨CT的数据采集。使用BTS红外捕捉系统、Kistler三维测力台采集太极(八法五步)7组步法动作的运动和力学数据,利用Anybody 7.2骨肌模型的多体动力学仿真技术计算下肢关节动力学参数,结合Workbench 19.2对股骨进行应力计算分析。结果与结论:①利用Workbench软件分析得出了7组步法动作的股骨应力结果,7组动作的应力峰值由大至小顺序是:退步捋势(22.00 MPa)、退步採势(19.379 MPa)、左右移步挤按(9.35 MPa)、左右移步肘靠(6.30 MPa)、进步掤势(4.68 MPa)、进步挒势(2.57 MPa)、中定独立势(0.31 MPa)。②在7组步法动作中2种向后退步动作股骨应力最大(P<0.05),且在7组动作运动过程中的股骨最大应力位置均不同。③上述结果证实,在太极(八法五步)7种步法动作练习时,股骨应力阈值和最大应力位置会随着5种方向(7组动作)运动不同而变化,通过连续训练能够全面地刺激股骨体,进步动作对于股骨体正面和外侧上端影响较大,退步动作对股骨体后面和内侧影响较大,左右横向步法动作主要是股骨体两侧对称受力。④初学者要根据不同步法动作的受力特点来进行针对训练,进步动作和退步动作训练时要注重太极拳的旋转用力以及左右横移步法动作训练时的内侧对抗用力,根据自身薄弱问题,对太极拳训练步法有所侧重,进而达到更好的锻炼效果。

Automatic Bone Surface Restoration for Markerless Computer-Assisted Orthopaedic Surgery

An automatic markerless knee tracking and registration algorithm has been proposed in the literature to avoid the marker insertion required by conventional computer-assisted knee surgery,resulting in a shorter and less invasive surgical workflow.However,such an algorithm considers intact femur geometry only.The bone surface modification is inevitable due to intra-operative intervention.The mismatched correspondences will degrade the reliability of registered target pose.To solve this problem,this work proposed a supervised deep neural network to automatically restore the surface of processed bone.The network was trained on a synthetic dataset that consists of real depth captures of a model leg and simulated realistic femur cutting.According to the evaluation on both synthetic data and real-time captures,the registration quality can be effectively improved by surface reconstruction.The improvement in tracking accuracy is only evident over test data,indicating the need for future enhancement of the dataset and network.

Primary Malignant Giant Cell Tumor of Bone:A Case Report

Primary malignant giant cell tumor of bone is clinically rare,lack of specificity,and often misdiagnosed.Currently,related literature about this tumor remains scarce.One case of primary malignant giant cell tumor of bone was diagnosed and treated in our hospital,and the treatment effect was satisfactory.There was no recurrence or metastasis in 2 years of followup.The report is as follows.