Assessment of the local blood supply when femoral neck fracture occurs:advances in the anatomy research and its clinical application / 中国骨伤

The stability of internal fixation of femoral neck fractures can be obtained through surgical techniques, the configuration of screws and bone grafting, etc. However, the blood supply injury caused by fractures could not be completely reversed by the current medical management. Hence, the comprehensive evaluation of the residual blood supply of the femoral neck, to perioperatively avoid further iatrogenic injury, has become a hotspot. The anatomy of the extraosseous blood supply of the femoral neck has been widely reported, while its clinical application mostly involved the assessment of the medial circumflex femoral artery and retinacular arteries. However, further studies are needed to explore the prognosis of patients with these artery injuries, with different degrees, caused by femoral neck fractures. Direct observations of nutrient foramina in vivo are not possible with current clinical technologies, but it is possible to make reasonable preoperative planning to avoid subsequent femoral head necrosis based on the distribution features of nutrient foramina. The anatomy and clinical application studies of the intraosseous blood supply focused on the junction area of the femoral head and neck to probe the mechanism of femoral head necrosis. Thus, the intraosseous blood supply of other regions in the femoral neck remains to be further investigated. In addition, a blood supply evaluation system based on a three-level structure, extraosseous blood vessels, nutrient foramina, and intraosseous vascular network, could be explored to assist in the treatment of femoral neck fractures.

Review of closed reduction techniques for femoral neck fracture / 中国骨伤

For patients with femoral neck fractures who plan to undergo internal fixation, satisfied alignment of fracture ends is an important prerequisite for internal fixation stability and fracture healing. There are many reports on the reduction methods of displaced femoral neck fractures, which can be summarized into three categories:First, the solely longitudinal traction of lower limbs, supplemented by other manipulations such as rotation and compression; Second, the resultant force formed by the longitudinal traction of lower limbs and the lateral traction;the third is accomplished by vertical traction in the axis of femur with hip joint flexed. Each reduction method has its own advantages, but no single method can be applied to all fracture displacement. In this paper, some classical reduction techniques in the literatures are briefly reviewed. It is hoped that clinicians will not be limited to a certain reduction method, they should analyze the injury mechanism and fracture displacement process according to the morphology features and flexibly select targeted reduction methods to improve the success rate of closed reduction of femoral neck fracture.

Biomechanical analysis of four internal fixations for Pauwels Ⅲ femoral neck fractures with defects / 中国骨伤

OBJECTIVE@#To investigate the biomechanical characteristics of different internal fixations for Pauwels type Ⅲ femoral neck fracture with defect, and provide reference for the treatment of femoral neck fracture.@*METHODS@#Three-dimensional (3D) finite element models of femoral neck fractures were established based on CT images, including fracture and fracture with defects. Four internal fixations were simulated, namely, inverted cannulated screw(ICS), ICS combined with medial buttress plate, the femoral neck system (FNS) and FNS combined with medial buttress plate. The von Mises stress, model stiffness and fracture displacements of fracture models under 2 100 N axial loads were measured and compared.@*RESULTS@#When femoral neck fracture was fixed by ICS and FNS, the peak stress was mainly concentrated on the surface of the screw near the fracture line, and the peak stress of FNS is higher than that of ICS;When the medial buttress plate was combined, the peak stress was increased and transferred to medial buttress plate, with more obvious of ICS fixation. For the same fracture model, the stiffness of FNS was higher than that of ICS. Compared with femoral neck fracture with defects, fracture model showed higher stiffness in the same internal fixation. The use of medial buttress plate increased model stiffness, but ICS increased more than FNS. The fracture displacement of ICS model exceeded that of FNS.@*CONCLUSION@#For Pauwels type Ⅲ femoral neck fracture with defects, FNS had better biomechanical properties than ICS. ICS combined with medial buttress plate can better enhance fixation stability and non-locking plate is recommended. FNS had the capability of shear resistance and needn't combine with medial buttress plate.

Comparison of effect between internal fixation and total hip replacement in the treatment of displaced femoral neck fracture in middle age patients / 中国骨伤

OBJECTIVE@#To analyze and compare the clinical efficacy of internal fixation and total hip replacement in the treatment of displaced femoral neck fracture from 55 to 65 years.@*METHODS@#From September 2016 to August 2020, 86 patients with Garden type Ⅲ or Ⅳ femoral neck fracture were divided into two groups according to different surgical methods. Among them, 38 patients were treated with lag screws for internal fixation, there were 26 males and 12 females, aged 55 to 64 years old with an average of(60.2±3.1) years;the other 48 patients were treated with total hip replacement, including 28 males and 20 females, aged from 57 to 65 years old with an average of(61.3±3.8) years. The time from injury to operation ranged from 1 to 3 days. The reoperation rate, incidence of deep infection, Harris score of hip joint function, visual analogue scale(VAS) of pain and patients reported outcome scores(European five-dimensional Health Questionnaire, EQ-5D) were compared between two groups.@*RESULTS@#All patients were followed up for 24 to 54 months with an average of (35.8±10.3) months. There was significant difference in reoperation rate between two groups (P<0.05). There was no significant difference on the incidence of deep infection, hip Harris score and VAS between two groups(P>0.05) . The postoperative EQ-5D score of patients with internal fixation was lower than that of total hip replacement, and the difference was statistically significant(P<0.05).@*CONCLUSION@#Both the surgery of internal fixation and total hip replacement have similar effect in short-and medium term among the patients aged 55 to 65 years old. However, for the reoperation rate, the group of internal fixation was higher than that of total hip replacement. For the subjective functional score of patients, the group of internal fixation was lower than that of total hip replacement.

Comparison of curative effect between percutaneous compression plate and cannulated compression screw in the treatment of displaced femoral neck fractures in young and middle-aged patients / 中国骨伤

OBJECTIVE@#To compare the efficacy of percutaneous compression plate and cannulated compression screw in the treatment of displaced femoral neck fractures in young and middle-aged patients.@*METHODS@#From January 2015 to July 2020, 68 young and middle-aged patients with displaced femoral neck fracture were retrospectively analyzed. Among them, 31 cases were fixed by percutaneous compression plate (PCCP), and 37 cases were fixed by cannulated compression screw (CCS). General data such as gender, age, cause of injury, comorbidities, fracture classification and cause of injury of two groups were collected. The operation time, intraoperative blood loss, hospital stay, full weight bearing time, fracture healing time, visual analogue scale(VAS), Harris hip score and complications were compared between two groups.@*RESULTS@#Patients in both groups were followed up for more than 2 years. There were no significant differences in operation time, intraoperative blood loss, fracture reduction quality, hospital stay and VAS between two groups. The fracture healing time in PCCP group was significantly shorter than that in CCS group (t=-4.404, P=0.000). The complete weight bearing time of PCCP group was significantly shorter than that of CCS group (t=-9.011, P=0.000). Harris score of hip joint in PCCP group was better than that in CCS group 2 years after operation (P=0.002). Complications occurred in 3 cases (9.68%) in PCCP group, while 11 cases (29.72%) in CCS group, with a statistically significant difference (P=0.042).@*CONCLUSION@#Both PCCP and CCS can be used for the treatment of displaced femoral neck fractures in young and middle-aged people. Compared with CCS, PCCP fixation can achieve shorter fracture healing time and create conditions for early full weight bearing. PCCP results in higher hip score and lower complications.

Comparison of curative effect between Tianji robot assisted screw placement and traditional cannulated screw internal fixation for femoral neck fracture / 中国骨伤

OBJECTIVE@#To investigate the clinical efficacy and advantages of Tianji orthopedic robot assisted cannulated screw internal fixation for femoral neck fracture.@*METHODS@#The clinical data of 41 patients with femoral neck fracture who underwent internal fixation with cannulated screws from January 2019 to January 2022 were retrospectively analyzed. According to different surgical methods, they were divided into Tianji robot group and traditional cannulated screw fixation group (traditional operation group). Among them, there were 18 patients in Tianji robot group including 8 males and 10 females with age of (56.00±4.22) years old, Garden typeⅠ (4 cases), type Ⅱ (11 cases), type Ⅲ (2 cases), and type Ⅳ (1 case). There were 23 patients in the traditional operation group, including 10 males and 13 females, aged (54.87±4.81) years old;there were 5 cases of Garden typeⅠ, 14 cases of type Ⅱ, 3 cases of type Ⅲ and 1 case of type Ⅳ. The operation time, intraoperative blood loss, fluoroscopy times, guide needle placement times, operation costs and other indicators were observed and compared between two groups. Harris score was used to evaluate hip joint function 12 months after operation.@*RESULTS@#The wounds of all patients healed in Grade A without complications. There were significant differences between two groups in terms of operation time, times of intraoperative fluoroscopy, times of guide needle placement, amount of intraoperative bleeding, and operation cost (P<0.05). All 41 patients were followed up for at least 12 months. The fractures of both groups were healed. There was no infection, screw loosening, fracture displacement and femoral head necrosis in Tianji robot group during follow-up;Screw loosening occurred in 2 patients in the traditional operation group during follow-up. At 12 months after operation, Harris hip joint function score of Tianji robot group was higher than that of traditional operation group in daily activity, lameness, joint activity score and total score (P<0.05).@*CONCLUSION@#Tianji robot assisted nail placement is a better method for the treatment of femoral neck fracture, which improves the surgical efficiency, is more accurate, has higher success rate of one-time nail placement, shorter operation time, less radiation, and has better hip joint function recovery after surgery.

Disastrous triad of femoral head:femoral neck fracture meeting fracture-dislocation of femoral head / 中国骨伤

Femoral head and ipsilateral femoral neck fractures are serious and complicated injuries, which usually yield unsatisfactory results using conventional hip-preserving surgery. The key point of the management and prognosis mainly lies in femoral neck fractures. An apparent and consecutive relationship exists between femoral neck fractures and femoral head fracture-hip dislocation in such injuries. It is believed that disastrous triad of femoral head (DTFH) could summarize these specific injuries, and reflect the injury mechanism and prognostic characteristics. Based on our clinical observation and literature review, DTFH could be divided into three subgroups:TypeⅠ, common DTFH, in which femoral neck fractures occur following femoral head fractures-hip dislocation due to the same trauma; TypeⅡ, iatrogenic DTFH, in which femoral neck fractures come out in the caring process of femoral head fractures-hip dislocation; Type Ⅲ, stressed DTFH, in which femoral neck fractures occur after the management of femoral head fractures-hip dislocation. In the scenario, the line of femoral neck fractures locates distally to the femoral head fractures. Herein, we will discuss clinical characteristics of these types of DTFH.

Application of 3D printing percutaneous guide plate in closed reduction and cannulated screw internal fixation of femoral neck fracture / 中国骨伤

OBJECTIVE@#To investigate the application of 3D printing percutaneous surgical guide plate in closed reduction and cannulated screw internal fixation of femoral neck fracture.@*METHODS@#The clinical data of 12 patients with femoral neck fracture from March 2019 to March 2022 were retrospectively analyzed. Patients were divided into observation group and control group according to different operation plans, with 6 cases in each group. The observation group received percutaneous operation guide plate assisted closed reduction and hollow screw internal fixation, while the control group received closed reduction and hollow compression screw internal fixation. The operation time, intraoperative blood loss, fluoroscopy times, and Kirschner needle puncture times were compared between two groups. The location of screws were recordedon postoperative X-ray films, follow-up time, time of complete fracture healing, Harris score of hip joint and the incidence of complications were recorded on postoperative X-ray films.@*RESULTS@#The operation time of observation group (32.17±6.18) min was shorter than that of control group (53.83±7.31) min (P<0.05). The amount of intraoperative bleeding in the observation group (18.33±2.94) ml was less than that in the control group (38.17±5.56) ml(P<0.05). The times of fluoroscopy in the observation group (7.50±1.05) were less than those in the control group (21.00±4.82) (P<0.05). The number of Kirschner needle punctures (8.00±0.63) in observation group was less than that in control group (32.67±3.08) (P<0.05). The follow-up time was(12.88±0.74) months in observation group and (12.83±0.72) months in control group, there was no significant difference between two groups (P>0.05). One year after operation, Harris score of hip joint in the observation group was(82.00±4.52) points, while that in the control group was(81.00±3.41) points, there was no significant difference between two groups(P>0.05). The time of complete fracture healing in the observation group was (7.50±1.05) months, while that in the control group was (7.67±1.21) months, there was no significant difference between two groups(P>0.05). The parallelism of the screws in the observation group was (0.50±0.11) ° and (0.76±0.15) °, which were lower than that in the control group (1.57±0.31) ° and (1.87±0.21) ° (P<0.05). The screw distribution area ratio (0.13±0.02) cm2 in the observation group was higher than that in the control group (0.08±0.01) cm2 (P<0.05). No complications such as necrosis of femoral head, nonunion of fracture, shortening of femoral neck and withdrawal of internal fixation occurred in both groups.@*CONCLUSION@#The application of 3D printing percutaneous surgical guide plate improves the accuracy and safety of closed reduction and cannulated screw internal fixation for femoral neck fracture. It has the advantages of minimally invasive, reducing radiation exposure, fast and accurate, shortening the operation time and reducing intraoperative bleeding.

Surgical treatment for ipsilateral femoral neck and shaft fracture / 中国骨伤

OBJECTIVE@#To retrospectively analyze efficacy of single structure internal fixation and double structure internal fixation in the treatment of ipsilateral femoral shaft and neck fracture, and analyze their indications.@*METHODS@#From June 2015 to December 2020, 21 patients with ipsilateral femoral shaft and femoral neck fracture were treated, including 14 males and 7 females, aged 23 to 69 years old with an average of(38.1±12.9) years old. According to different femoral shaft fracture sites, some patients were fixed with cephalomedullary implant for both femoral neck and the femoral shaft(single structure, InterTan or PFNA Ⅱ), some patients were fixed with cannulated screws for the femoral neck and a retrograde locking nail for the femoral shaft (dual structure), and postoperative function and complications were recorded during follow-up. In 10 cases of single-structure fixation, the femoral necks were all basicervical fractures, and the femoral shaft fractures were located in the proximal isthmus;11 cases were double-structure fixation, 9 cases in 11 were basal type of femoral neck, 2 cases in 11 were neck type, and the femoral shaft fractures were located in the isthmus and the distal isthmus.@*RESULTS@#All patients were followed up for 12 to 27 months. No femoral head necrosis, deformity, delay or nonunion occurred in the patients with single-structure fixation, and no delayed union or nonunion occurred in femoral shaft fractures;At the final follow-up, Harris score of patients with single-structure fixation was 91.8±4.1, with 8 cases were excellent and 2 cases were good. The fractures of patients with dual-structure fixation achieved good union without femoral head necrosis, except 1 case of femoral shaft fracture had delayed union;At the final follow-up, Harris score of patients with dual-structure fixation was 92.4±5.9, 7 cases were excellent, 3 cases were good, and 1 case was fair.@*CONCLUSION@#Good reduction and fixation is the key to the treatment of such fractures. Both the single-structure fixation and the dual-structure fixation are good methods, and it should be selected according to the locations of femoral shaft and femoral neck fractures. Single-structure fixation is a good choice for femoral shaft fractures located at the proximal isthmus and basal femoral neck fractures. For isthmus and distal femoral shaft fractures combined with ipsilateral femoral neck fractures, dual-structure fixation is recommended.

Short term follow-up of unstable femoral neck fractures in young adults treated with femoral neck system and cannulated compression screws / 中国骨伤

OBJECTIVE@#To investigate the clinical efficacy of femoral neck system(FNS) and three cannulated compression screws(CCS) in the treatment of unstable femoral neck fractures in young adults.@*METHODS@#The clinical data of 52 young and middle-aged patients with unstable femoral neck fractures admitted from August 2018 to August 2021 were reviewed and analyzed. All patients were divided into two groups according to the internal fixation method, 25 cases were treated with FNS fixation, 27 cases were treated with closed reduction and 3 CCS inverted triangular distribution. The operation time, incision length, intraoperative bleeding, hospitalization expenses and fracture reduction quality of two groups were recorded and compared;The patients were followed up regularly after operation. The fracture healing time, complete weight-bearing time and postoperative complications(nonunion, femoral neck shortening, femoral head necrosis) of two groups were compared. The Harris score was used to evaluate hip function 6 months after surgery.@*RESULTS@#The operation was successfully completed in both groups. The patients in FNS group had more bleeding, longer incision length and higher hospitalization cost than CCS group(P<0.01). There ware no significant difference in operation time and Garden index between two groups(P>0.05). Patients in both groups were followed up for 6 to 32 months.The fracture healing time in FNS group was less than that in CCS group, the time of complete weight bearing after surgery was earlier than that in CCS group, and the hip Harris score was higher than that in CCS group (P<0.01). There were no internal fixation fracture complications in two groups during follow-up. In the FNS group, there were 4 cases of avascular necrosis of the femoral head and 2 cases of femoral neck shortening, of which 3 cases underwent total hip replacement due to avascular necrosis of the femoral head. In the CCS group, there were 2 cases of nonunion, 9 cases of avascular necrosis of the femoral head, and 11 cases of femoral neck shortening, among which 5 cases underwent total hip replacement due to nonunion and avascular necrosis of the femoral head.@*CONCLUSION@#With simple operation, rotational stability and angular stability, FNS enables patients to start functional exercise as early as possible and reduces the incidence of postoperative complications of unstable femoral neck fracture. It is a new choice for the treatment of unstable femoral neck fracture in young adults.

Treatment of femoral neck fractures with closed reduction assisted by joystick technique and cannulated screw fixation / 中国修复重建外科杂志

OBJECTIVE@#To investigate the effectiveness of joystick technique assisted closed reduction and cannulated screw fixation in the treatment of femoral neck fracture.@*METHODS@#Seventy-four patients with fresh femoral neck fractures who met the selection criteria between April 2017 and December 2018 were selected and divided into observation group (36 cases with closed reduction assisted by joystick technique) and control group (38 cases with closed manual reduction). There was no significant difference in gender, age, fracture side, cause of injury, Garden classification, Pauwels classification, time from injury to operation, and complications (except for hypertension) between the two groups ( P>0.05). The operation time, intraoperative infusion volume, complications, and femoral neck shortening were recorded and compared between the two groups. Garden reduction index was used to evaluate the effect of fracture reduction, and score of fracture reduction (SFR) was designed and was used to evaluate the subtle reduction effect of joystick technique.@*RESULTS@#The operation was successfully completed in both groups. There was no significant difference in operation time and intraoperative infusion volume between the two groups ( P>0.05). All patients were followed up 17-38 months, with an average of 27.7 months. Two patients in the observation group received joint replacement due to failure of internal fixation during the follow-up, and the other patients had fracture healing. Within 1 week after operation, the Garden reduxtion index of the observation group was better than the control group; the SFR score of the observation group was also higher than that of the control group; the proportion of femoral neck shortening within 1 week after operation and at 1 year after operation in the observation group were lower than those in the control group. The differences of the above indexes between the two groups were significant ( P<0.05).@*CONCLUSION@#The joystick technique can improve the effectiveness of closed reduction of femoral neck fractures and reduce the incidence of femoral neck shortening. The designed SFR score can directly and objectively evaluate the reduction effect of femoral neck fracture.

Femoral head necrosis rate and risk factors after internal fixation of femoral neck fracture:a Meta-analysis / 中国骨伤

OBJECTIVE@#To study the incidence and risk factors of osteonecrosis of the femoral head (ONFH) after internal fixation in adult patients with femoral neck fracture (FNF) after 2000, and identify high-risk population of ONFH.@*METHODS@#PubMed, Medline, The Cochrane Library, CNKI, Wanfang and VIP Database were searched to collect all the literatures on ONFH and related risk factors after internal fixation of FNF from January 1th 2000 to July 1th 2020. Study extraction was performed according to inclusion and exclusion criteria. Endnote X9 and Excel 2019 were used for literatures extraction, management and data entry, and R Studio 3.6.5 software was used for Meta-analysis. Subgroup analysis, sensitivity analysis and publication bias detection were used to explore the sources of heterogeneity and the reliability of the evaluation results.@*RESULTS@#A total of 16 studies with 5521 patients were included. Meta-analysis showed that the incidence of ONFH after internal fixation for adult FNF was 14.5% [95% CI(0.126-0.165)]. Fracture displacement[OR=0.27, 95%CI(0.21-0.35)] and reduction quality [OR=0.15, 95%CI(0.09-0.27)] were related risk factors for ONFH. The results of subgroup rate analysis showed that the non-displaced fracture necrosis rate was 6.2%[95%CI(0.051-0.077)] and the displaced fracture necrosis rate was 20.4% [95%CI(0.166-0.249)];the good reduction fracture necrosis rate was 8.3%[95%CI(0.072-0.095)] and the poor reduction fracture necrosis rate was 35.5%[95%CI(0.233-0.500)]. The included literatures have good consistency and no publication bias.@*CONCLUSION@#After 2000, the total incidence of ONFH after internal fixation of adult FNF has decreased, while the necrosis rates of patients with displaced fracture and poor reduction are still at a high level. The interval between injury and surgery was not analyzed in this study because of the inconstant division in the original literature.

Prognosis of hip fracture in elderly patients with dementia / 中华全科医师杂志

Objective:To investigate the prognosis of hip fracture in elderly patients with dementia.Methods:From January 2012 to December 2017, 91 dementia patients aged (82.7±6.6)y (21 males and 70 females) with hip fracture were enrolled in the study; 91 non-dementia patients matched by age, gender and fracture type were selected as controls. There were 54 cases of intertrochanteric fracture and 37 cases of femoral neck fracture. The length of hospital stay, mortality within 30 days and 1 year, walking ability and risk of reoperation were compared between the two groups. The effect of dementia on the mortality after surgery was analyzed by adjusting confounding factors through multivariate logistic regression analysis.Results:There was no significant difference in the length of hospital stay between dementia group and non-dementia group [(13.95±7.33) vs.(12.63±8.68)d, t=1.12, P=0.266]. The incidence rate of perioperative complications in dementia group was higher than that in non-dementia group [63.7%(58/91) vs. 23.1%(21/91), χ 2 = 44.59, P<0.001]. The incidence of delirium in dementia group was higher than that in non-dementia group [35.3%(42/91) vs.13.2%(12/91), χ 2 = 5.71, P=0.017]. The incidence of pulmonary infection in dementia group was higher than that in non-dementia group [11.0%(10/91) vs. 2.2%(2/91), χ 2= 11.989, P<0.001]. There was no significant difference in 30-day fatality rate [7.7%(7/91) vs. 1.1%(1/91), χ 2= 3.27, P=0.071] between two groups; while the 1-year fatality rate in dementia group was higher than that in non-dementia group [27.5%(25/91) vs. 14.3%(13/91), χ 2= 4.79, P=0.029]. After adjusting for the differences of confounding factors between the two groups, dementia was an independent risk factor for 1-year mortality after hip fracture surgery ( OR = 1.852, 95 %CI:1.048-3.043, P= 0.022). For walking ability of 1 year after operation, 22 (33.3%) patients in dementia group walked independently, 38 (57.6%) patients partially walked independently, 6 (9.1%) patients were in bed; while in non-dementia group, 45 (57.7%) patients walked independently, 27 (34.6%) patients partially walked independently, 6 (7.7%) patients were in bed; there was significant difference between the two groups (χ 2= 8.82, P=0.012). There was no significant difference in reoperation rate between two groups [6.6%(6/91) vs. 5.5%(5/91), χ2=0.10, P=0.756]. Conclusion:Compared to non-dementia patients, dementia patients with hip fracture have poorer prognosis, higher incidence of perioperative complications, pulmonary infection and delirium, higher risk of mortality 1 year after operation, and poorer ability of independent walking.

A novel device for cannulated screwing for femoral neck fracture / 中华创伤骨科杂志

Objective:To evaluate our self-designed novel guide device for cannulated screwing in the treatment of femoral neck fracture.Methods:Between June 2019 and July 2020, 40 patients with femoral neck fracture were treated with cannulated screwing at Department of Orthopaedics, The Second Hospital Affiliated to Shanxi Medical University. They were divided into a manual group of 20 cases whose cannulated screwing was implemented by hand and a guide group of 20 cases whose cannulated screwing was implemented with the aid of our self-designed guide device. In the guide group, there were 5 males and 15 females, with an age of (48.4±10.2) years (from 18 to 63 years); there were 12 cases of types Ⅰ & Ⅱ and 8 cases of types Ⅲ & Ⅳ by the Garden classification. In the manual group, there were 8 males and 12 females, with an age of (49.8±8.4) years (from 18 to 60 years); there were 13 cases of types Ⅰ & Ⅱ and 7 cases of types Ⅲ & Ⅳ by the Garden classification. All fractures underwent closed reduction and internal fixation with 3 cannulated screws. The intraoperative fluoroscopy, operation time, femoral cortex drilling, angle between the guide pin and the femoral neck axis in the anteroposterior view, angle between the guide pin and the femoral neck axis in the lateral view, fracture healing time, Harris hip score and complications were compared between the 2 groups.Results:There was no significant difference in the preoperative general data between the 2 groups, showing comparability ( P>0.05). In the guide group, intraoperative fluoroscopy [(10.0±2.2) times], operation time [(41.8±5.6) min], femoral cortex drilling [(4.5±1.1) times], angle between the guide pin and the femoral neck axis in the anteroposterior view (3.0°±0.8°) angle between the guide pin and the femoral neck axis in the lateral view (3.9°±1.0°) and fracture healing time [(6.2±0.5) months] were significantly less or smaller than those in the manual group [(24.8±8.3) times, (60.0±15.3) min, (12.8±2.0) times, 7.2°±1.8°, 7.6°±2.6°, and (7.2±0.5) months] (all P<0.05). There was no significant difference in Harris hip score between the 2 groups ( P>0.05). None of the patients had wound infection, internal fixation displacement, fracture nonunion or screw breakage. Conclusions:Application of our self-designed guide device can shorten operation time, improve accuracy of needle insertion, and reduce drilling attempts in the femoral cortex, making cannulated screwing easier for femoral neck fractures.

Research of Building 3D Model in External Fixator for Proximal Femoral Fracture Based on Locking Plate Shape / 中国医疗器械杂志

The software of 3D-Modeling(UG NX 10.0) was used to design a new external fixator model for proximal femoral fracture, and fresh femoral cadaver specimens were used to simulate experimental operation. The results showed that the external fixator designed with the proximal femoral locking plate shape can improve the accuracy of Kirschner wire penetration into the femoral neck, reduce fluoroscopic and soft tissue incision injuries, and make a good stability and is easy to operate, which has a certain value for patients with proximal femoral fracture, such as intolerant surgery and poor physical condition.

Development of Novel Guide Device for Cannulated Screws Implantation in Femoral Neck Fracture Surgery / 中国医疗器械杂志

Cannulated Screw is a common internal fixation for the treatment of femoral neck fractures. However, the traditional implantation method has disadvantages such as inaccuracy and large radiation exposure. Based on the anatomical characteristics of the femoral neck and geometric principles, we develop a novel guide device for cannulated screws insertion. The cadaver experiment showed that it can improve the accuracy of cannulated screws implantation, reduce puncture attempts and the radiation exposure of doctors and patients.

Vibration Characteristics of Hollow Screws and Locking Plates for Treating Femoral Neck Fractures / 医用生物力学

Objective To investigate the influence from natural and constrained modal of the hip joint on internal fixation after implantation of hollow screws and locking plates for treating femoral neck fractures. Methods CT image data of a patient with femoral neck fracture were analyzed, boundary of the hip joint was extracted to generate a three-dimensional (3D) model of the hip joint, and the assembly of common internal fixation models and hip joint models was established. Finite element simulation was then conducted, with focus on vibration characteristics. Results Vibration had a certain effect on internal fixation stability of hollow screws and locking plates. The occurrence of torsion would destroy the fixation environment of hollow screws and locking plates, resulting in a small displacement at the fracture end. In a constrained state, the modal frequency range was lower. Deformation of the vibration shape mostly occurred at proximal end of the femoral head, leading to the loosening phenomenon of internal fixation and prosthesis. A method for judging the stability of internal fixation was proposed from the perspective of vibration characteristics, and it was found that the stability of internal fixation with hollow screws was better than that of proximal locking plates. Conclusions For choosing internal fixation, influences from natural frequency of the screw and plate should be considered, so as to avoid natural frequency of the femur, which may cause resonance. The results can be used as a guidance for the selection of internal fixation materials and the design of structure and configuration.

Risk factors for femoral neck fracture in elderly population / 中南大学学报(医学版)

OBJECTIVES@#To explore the risk factors for femoral neck fracture in elderly population.@*METHODS@#A total of 124 elderly patients (≥60 years old) in hospital for trauma were enrolled, including 71 patients (57%) with femoral neck fracture and 53 non-femoral neck fracture patients (43%). All patients' age, gender, body mass index (BMI), bone mineral density (BMD), thigh length and average circumference were collected. Single factor analysis and multivariate logistic regression analysis were performed to explore whether the above factors were risk factors for femoral neck fracture.@*RESULTS@#Single factor analysis showed that the age, gender, BMI, BMD, thigh length, and average thigh circumference between the 2 groups were statistically different (all @*CONCLUSIONS@#Older age, female, lower BMI index (low body weight), lower BMD (osteoporosis), longer thigh length, and lower average circumference are risk factors for femoral neck fracture in the elderly population.

Influences of structural changes after valgus impacted femoral neck fracture on hip range of motion: a 3D simulation test / 中华创伤骨科杂志

Objective:To determine the influences of structural changes after valgus impacted femoral neck fracture on hip range of motion (ROM) so as to provide evidence for clinical judgment of whether reduction is necessary or not in the internal fixation of such fractures.Methods:1. 3D reconstructions of the CT hip scans were performed for the 73 patients who had been treated at Department of Orthopaedic Surgery, Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University for valgus impacted femoral neck fractures from January 2019 to April 2019.The femoral neck-shaft angle, anteversion angle, femoral offset, axial alpha angle, lateral center edge angle (LCEA), anterior center edge angle (ACEA) and center displacement were measured and compared between the affected and healthy sides to determine the influences of the fracture on the above indexes. 2. Hip motions (flexion and MIR-90°) were simulated on bilateral sides to determine the influences of structural changes after fracture on hip ROM using stepwise regression and Logistic regression. 3. The distribution of femoral-acetabular contact points on the femoral side was observed in simulation of hip flexion to detect the potential area for femoracetabular impingement (FAI) induced by the fracture displacement.Results:1. The valgus impacted femoral neck fractures had significant influences on femoral neck-shaft angle, anteversion angle, femoral offset and axial alpha angle. Compared with the healthy side, on average, the femoral neck-shaft angle increased by 5.1°, anteversion angle decreased by 6.5°, femoral offset decreased by 8.2 mm and axial alpha angle increased by 9.7° on the affected side, showing significant differences ( P<0.05).The displacements of the femoral head center averaged 9.2 mm. There was no significant difference in LCEA or ACEA between the affected and healthy sides ( P>0.05). 2. Compared with the healthy side, on average, the simulated hip flexion decreased significantly by 27.0° and the hip MIR-90° decreased significantly by 20.3° on the affected side after fracture ( P<0.05). Regression analysis showed that femoral anteversion angle, ACEA and displacement of the femoral head center had a significant influence on hip ROM, especially the anteversion angle. When the anteversion angle decreased by more than 7.1°, the hip flexion would decrease by at least 20%. 3. The points of FAI distributed more widely on the fracture side. Compared with the healthy side, the impact points extended outward and upward in hip flexion and extended inwardly in hip MIR-90° on the affected side. Conclusions:After a valgus impacted femoral neck fracture, if the femoral anteversion angle has been decreased by more than 7.1°, the hip ROM can be greatly influenced and the points of FAI can be distributed more widely. Therefore, reduction should be recommended before internal fixation of the fracture.

Analysis on Mechanical Characteristics of Femoral Neck Fracture with Different Reduction Qualities / 医用生物力学

Objective To investigate biomechanical characteristics of femoral neck fracture with different reduction qualities. Methods Three cases of Sawbones artificial femoral models were selected, and two cases of Pauwel III femoral neck fracture were modeled. Three cannulated screws were inserted into the models in the form of inverted triangle to fix the fracture. Two cases maintained different reduction qualities (defined as Model 1 and Model 2). In the 3 third case, no modeling operation was performed (defined as intact model). Then the strain gauges were respectively pasted on regions of interest of the 3 femoral models. Finally, the femur model was applied with the vertical load on mechanical testing machine. Results When the displacement of femoral head reached 4 mm, the average load of intact model, Model 1 and Model 2 was (236.30±5.35), (196.57±3.56), (69.50±2.95) N, showing significant differences. When the displacement of femoral head reached 5 mm, the average load of intact model, Model 1 and Model 2 was (276.7±3.40)，(232.93±2.64)，(80.83±4.54) N, showing significant differences. Conclusions The lower the reduction quality of the femoral neck fracture, the weaker the ability of the femur to bear stress, the higher the probability of nonunion, re-fracture and femoral head necrosis in the process of postoperative rehabilitation.