The hip fracture incidence in the high-risk area Oslo continues to decline.

Oslo in Norway has had the highest incidence of hip fractures in the world. The incidence in Oslo has been thoroughly described every decade since the late 1970s. The incidence in Oslo has previously been higher compared to the rest of Norway but has now decreased to a level below the country average. PURPOSE: The purpose of this study was to report the incidence of hip fractures in Oslo in 2019 and compare it with the incidence rates from the previous four decades. METHODS: Patients residing in Oslo in 2019 with a new hip fracture identified by searching the Oslo hospital's patient administrative systems and protocols from the operating theaters. The diagnosis was verified through medical records and/or radiographs. To compare with previous studies, the direct standardization method was used with the population of Oslo in 2019 as the standard. RESULTS: A total of 758 hip fractures, 70% women, were identified in 2019. The age-standardized incidence rates per 10,000 person-years in 2019 (95% CI) were 45 (41.1-48.8) for women and 30 (25.8-33.8) for men. In women, there has been a continuous decline in age-standardized rates the last three decades and in men the last two decades. The most pronounced decline was seen in the oldest age groups over 70 years. There has been a secular decline in both cervical and trochanteric fractures; however, the decrease in trochanteric fractures was most distinct for males, with more than two times higher risk in 1996/1997 compared to 2019. CONCLUSION: Incidence rates for hip fractures in Oslo in 2019 were the lowest rate reported since 1978. The decrease was significant for both men and women. For the first time, the incidence rates are below the national rates of Norway. However, the rates are still among the highest worldwide.

Histomorphometric analysis of patients with femoral neck fracture and 25-hydroxyvitamin D deficiency: a cross-sectional study.

INTRODUCTION: Vitamin D deficiency causes osteoporosis, bone mineralization disorders, and osteomalacia. Osteomalacia is diagnosed using blood biochemical tests, clinical symptoms, and imaging; however, accurate detection of mineralization disorders requires tissue observation. We investigated the prevalence of bone mineralization disorders and their relationship with serum 25-hydroxyvitamin D (25OHD) levels in patients with untreated osteoporosis with femoral neck fractures. MATERIALS AND METHODS: A non-demineralized specimen was prepared from the femoral head removed during surgery in 65 patients. Bone histomorphometry of cancerous bone in the femoral head center was conducted. Osteoid volume per bone volume (OV/BV) and osteoid thickness (O.Th) were measured as indicators of mineralization disorder. RESULTS: The mean serum 25OHD level (11.9 ± 5.7 ng/mL) was in the deficiency range (< 12 ng/mL). There were no clinically diagnosed cases of osteomalacia (OV/BV > 10% and O.Th > 12.5 µm); however, one case of mineralization disorder, considered histologically pre-osteomalacia (OV/BV > 5% and O.Th < 12.5 µm), was observed (OB/BV, 17.6%; O.Th, 12.3 µm). Excluding this case, those with severe (25OHD < 12 ng/mL, at risk of osteomalacia; n = 39) and non-severe deficiency (25OHD ≥ 12 ng/mL; n = 25) did not significantly differ in OV/BV (%; 0.77 ± 0.54 vs. 0.69 ± 0.38, p = 0.484) or O.Th (µm; 5.32 ± 1.04 vs. 5.13 ± 0.78, p = 0.410). Further, 25OHD and OV/BV were not significantly correlated (R = - 0.124, p = 0.327). CONCLUSION: This is the first study in the twenty-first century to examine serum 25OHD concentrations and bone mineralization disorders in Japanese patients with osteoporosis. The results indicate that vitamin D deficiency does not necessarily cause bone mineralization disorders and rarely leads to osteomalacia.

Evaluating Pain Management from Peripheral Nerve Block for Geriatric Patients following Bipolar Hemiarthroplasty for Displaced Femoral-Neck Fracture.

INTRODUCTION: The purpose of this study was to evaluate peripheral nerve block (PNB) effectiveness in postoperative pain management and surgical outcomes for displaced femoral-neck fracture in geriatric patients (>70 years) who underwent bipolar hemiarthroplasty (BHA). METHODS: From January 2017 to December 2021, 231 geriatric patients with displaced femoral-neck fracture who consecutively underwent BHA were retrospectively reviewed. Patients were divided into two groups: the patient-controlled analgesia (PCA) group (n = 132) who received only intravenous (IV) PCA for postoperative pain management, and all others who received PNB with IV PCA (PNB+PCA) such as femoral nerve block or fascia iliaca compartment block after surgery (n = 99). Primary outcomes were postoperative visual analog scale (VAS) at rest and during activity at 6, 24, and 48 h postoperatively. Secondary outcomes were postoperative complications, changes in hemoglobin, length of hospital stay, and total morphine usage after surgery. RESULTS: Postoperative resting VAS at 6 h and 48 h was significantly lower in the PNB+PCA group compared with the PCA group (p = 0.075, p = 0.0318, respectively). However, there was no significant difference in either resting VAS at 24 h or active VAS. Complications of pneumonia and delirium until 1 month postoperative were significantly lower in the PNB + PCA group than the PCA group (p = 0.0022, p = 0.0055, respectively). CONCLUSION: PNB with IV PCA seems to have a beneficial effect on geriatric femoral-neck patients who underwent BHA with postoperative analgesia for reducing postoperative resting pain and complications, especially pneumonia and delirium.

Postoperative rehabilitation exercise experiences of geriatric patients with femoral neck fractures based on the perspective of medical staff: a qualitative study.

BACKGROUND: The incidence of femoral neck fractures in older adults is increasing each year. Active and reasonable postoperative rehabilitation exercises can restore the activity of geriatric patients with femoral neck fractures to a great extent, while also avoiding bedridden complications and re-fractures. This study explores the perspectives, experiences, and recommendations of medical staff regarding the implementation status, existing problems, promoting factors, and hindering factors of post-surgical rehabilitation exercises for geriatric patients with femoral neck fractures. The ultimate goal is to further optimize rehabilitation exercise programs and to expedite this process for patients. METHODS: A qualitative, descriptive phenomenological study was conducted. A total of 21 clinical medical staff were selected using the purposive sampling method for semi-structured interviews. A content analysis method was used to collate and analyze the collected interview data. RESULTS: A total of 2 themes and 6 sub-themes were defined. The themes consisted of multiple obstacles occurring during the implementation of rehabilitation exercises and the scientific cognition of medical staff on these exercises. Respondents found that patient initiative during rehabilitation exercises was insufficient, that the comprehensiveness and continuity of exercises could not be guaranteed, and that unification between textbook theory and clinical practice was incomplete. Moreover, respondents believed that their professional quality should be excellent, but that staffing and organizational management required optimization, and that support was required for the implementation of rehabilitation exercises. CONCLUSION: This study investigated the opinions and experiences of medical staff during postoperative rehabilitation exercises in geriatric patients with femoral neck fractures. Collaborative efforts should fully engage hospitals, communities, and families, enhance the alignment of health education with patient needs, advance the scientific development of an integrated medical model by refining the curriculum and teaching system, and significantly elevate the level of medical science and technology. This study will serve as a valuable reference for the establishment of future professional, and personalized rehabilitation programs tailored for geriatric patients with femoral neck fractures.

A finite element analysis of a low-profile femoral neck system of screws in sleeves in a vertical femoral neck fracture model.

BACKGROUND: Femoral neck system (FNS) has exhibited some drawbacks, such as non-fit of the plate with the lateral femoral cortex, postoperative pain, and the potential risk of subtrochanteric fractures. We have developed a low-profile FNS system that addresses some compatibility issues in FNS. In this study, we conducted finite element analysis on the 1-hole FNS (1 H-FNS), 2-holes FNS (2 H-FNS), and low-profile FNS (LP-FNS) and compared their biomechanical performance. METHODS: After the mesh convergence analysis, we established three groups of 1 H-FNS, 2 H-FNS, and LP-FNS. The interfragmentary gap, sliding distance, shear stress, and compressive stress and the bone-implant interface compression stress, stiffness, and displacement were determined under the neutral, flexion, or extension conditions of the hip joint, respectively. The stress and displacement of the femur after the implant removal were also investigated. RESULTS: (1) There were no obvious differences among the three FNS groups in terms of the IFM distance. However, the LP-FNS group showed less rotational angle compared with conventional FNS (neutral: 1 H-FNS, -61.64%; 2 H-FNS, -45.40%). Also, the maximum bone-implant interface compression stress was obviously decreased under the neutral, flexion, or extension conditions of the hip joint (1 H-FNS: -6.47%, -20.59%, or -4.49%; 2 H-FNS: -3.11%, 16.70%, or -7.03%; respectively). (2) After the implant removal, there was no notable difference in the maximum displacement between the three groups, but the maximum von Mises stress displayed a notable difference between LP-FNS and 1 H-FNS groups (-15.27%) except for the difference between LP-FNS and 2 H-FNS groups (-4.57%). CONCLUSIONS: The LP-FNS may not only provide the same biomechanical stabilities as the 1 H-FNS and 2 H-FNS, but also have more advantages in rotational resistance especially under the neutral condition of the hip joint, in the bone-implant interface compression stress, and after the implant removal. In addition, the 1 H-FNS and 2 H-FNS have similar biomechanical stabilities except for the maximum von Mises stress after the implant removal. The femur after the LP-FNS removal not only is subjected to relatively little stress but also minimizes stress concentration areas.

Pre-sliding technique to improve femoral neck system against the shortening: a retrospective cohort study.

OBJECTIVE: To investigate the efficacy of using pre-sliding technique to prevent postoperative shortening of displaced femoral neck fracture fixed with femoral neck system (FNS). METHODS: Retrospective analysis of 110 cases of displaced femoral neck fracture treated with femoral neck system from September 2019 to November 2022 in our center, which were divided into 56 cases in the pre-sliding group and 54 cases in the traditional group. The baseline data such as gender, age, side, mechanism of injury, fracture type, operation time, intraoperative bleeding were recorded and compared between the two groups, and the quality of fracture reduction, shortening distance, Tip Apex Distance (TAD), union time, Harris score of the hip were also compared between the two groups. RESULTS: The TAD value of the pre-sliding group was smaller than that of the traditional group, and the difference was statistically significant (P < 0.001). The shortening distance in both groups on postoperative day 1 was smaller in the pre-sliding group than in the traditional group, but the difference was not statistically significant (P = 0.07), and the shortening distance was smaller than in the traditional group at 1, 3, 6, and 12 months postoperatively, and the difference was statistically significant (all P < 0.001). Of the 110 cases, 34 (30.9%) had moderate or severe shortening, of which 24 (44.4%) were in the traditional group and 10 (17.9%) in the pre-sliding group, and the difference was statistically significant (P < 0.001), and the Harris score at 1 year, which was higher in the pre-sliding group than in the traditional group, and the difference between the two groups was statistically significant (P < 0.001). There was no statistically significant difference in the comparison of baseline data such as gender, age, side, mechanism of injury, fracture type, operation time, intraoperative bleeding, and quality of reduction between the two groups (all P > 0.05), and no statistically significant difference in fracture healing time between the two groups (P = 0.113). CONCLUSION: The use of the pre-sliding technique of displaced femoral neck fracture fixed with FNS reduces the incidence of moderate and severe shortening, improves the postoperative TAD value, and improves the hip function scores, with a satisfactory midterm efficacy.

Bio-mechanical effects of femoral neck system versus cannulated screws on treating young patients with Pauwels type III femoral neck fractures: a finite element analysis.

INTRODUCTION: As a novel internal fixation for femoral neck fractures, the femoral neck system has some advantages for young Pauwels type III femoral neck fractures without clear biomechanical effects and mechanisms. Thus, the objection of the study is to realize the biomechanical effects and mechanism of FNS cannulated screws on treating young patients with Pauwels type III femoral neck fractures compared to cannulated screws which are commonly used for femoral neck fractures by finite element analysis. METHODS: Firstly, the model of young Pauwels type III femoral neck fractures, femoral neck system (FNS), and three cannulated screws (CS) arranged in an inverted triangle were established, and the internal fixations were set up to fix young Pauwels type III femoral neck fractures. Under 2100 N load, the finite element was performed, and the deformation, peak von Mises stress (VMS), and contact at fracture segments were recorded to analyze the biomechanical effects and mechanism of FNS and three-CS fixing young Pauwels type III femoral neck fractures. RESULTS: Compared to three-CS, the deformation of the whole model, internal fixation, and fracture segments after FNS fixation were lower, and the peak VMS of the whole model and the internal fixation after FNS were higher with lower peak VMS of the distal femur and the fracture segments. With a sticking contact status, the contact pressure at fracture segments after FNS fixation was lower than that of three-CS. CONCLUSIONS: FNS can provide better mechanical effects for young patients with Pauwels type III femoral neck fractures, which may be the mechanical mechanism of the clinical effects of FNS on femoral neck fracture. Although there is high stress on FNS, it is still an effective and safe internal fixation for young patients with Pauwels type III femoral neck fractures.

Comparison of young femoral neck fractures treated by femoral neck system, multiple cancellous screws and dynamic hip screws: a retrospectively comparison study.

BACKGROUND: Implant choice for the fixation of femoral neck fracture is one of the most important management controversies. This study aims to evaluate and compare the short-term outcomes associated with the use of the Femoral Neck System (FNS), Multiple Cancellous Screws (MCS), and Dynamic Hip Screws (DHS) in treating femoral neck fractures in a young patient population. METHODS: From June 2018 to June 2021, a total of 120 surgeries for a primary femoral neck fracture were retrospectively analyzed. This review encompassed demographic details of the patients and the mechanisms behind the injuries. Key surgical parameters such as operation duration, intraoperative blood loss, fluoroscopy duration, and hospital stay were meticulously documented. The employed surgical technique was described. All patients were followed up at 6 weeks, 3 months, 6 months, and 12 months postoperatively. Avascular necrosis of the femoral head (AVN), nonunion, malreduction, implant failure or other complications were noted. The functional status at the last follow-up was assessed using the Harris functional scoring criteria. RESULTS: There were 90 males and 30 females, with a mean age of 40.4 years. As to patient characteristics, there were no significant differences between the three groups. DHS group showed longer operation time(52.15 ± 4.80 min), more blood loss(59.05 ± 5.87 ml) and longer time of hospitalization(7.6 ± 0.90 d) than FNS group (39.65 ± 2.84 min, 45.33 ± 9.63 ml and 4.87 ± 0.48 d) and MCS group (39.45 ± 3.10 min, 48.15 ± 7.88 ml and 5.04 ± 0.49 d) (p < 0.05). In addition, the time of fluoroscopy in FNS group (15.45 ± 3.67) was less than that in MCS group (26.3 ± 4.76) and DHS group (27.1 ± 5.67) (p < 0.05). The cost of FNS group(44.51 ± 2.99 thousand RMB) was significantly higher than the MCS and DHS groups. The FNS, MCS and DHS groups showed a similar mean length of femoral neck shortening (LFNS) and Harris score. The FNS, MCS and DHS groups showed a similar mean rate of AVN and internal fixation failure. CONCLUSIONS: Following successful fracture reduction, FNS, MCS, and DHS are effective for in the young femoral neck fractures. No difference was found in complications between the three groups. However, the reduced fluoroscopy time associated with FNS contributes to shorter operation durations. The adoption of minimally invasive techniques correlates with decreased blood loss and shorter hospital stays. Nevertheless, these advantages may be offset by the potential economic burden they impose.

Association of osteoporotic fractures of femoral neck and femoral neck geometric parameters in native Chinese women.

BACKGROUND: Although it is generally believed that the femoral neck fracture is related to the femoral neck geometric parameters (FNGPs), the association between the risk of osteoporotic fracture of the femoral neck and FNGPs in native Chinese women is still unclear. METHODS: A total of 374 female patients (mean age 70.2 ± 9.32 years) with osteoporotic fracture of the femoral neck, and 374 non-fracture control groups were completely matched with the case group according to the age ratio of 1:1. Using DXA bone densitometer to measured eight FNGPs: the outer diameter (OD), cross-sectional area (CSA), cortical thickness (CT), endocortical diameter (ED), buckling ratio (BR), section modulus (SM), cross-sectional moment of inertia (CSMI), and compressive strength index (CSI) at the narrowest point of the femoral neck. RESULTS: Compared with the control group, the average values of OD (2.9%), ED (4.5%), and BR (26.1%) in the patient group significantly increased (p = 0.015 to < 0.001), while CSA (‒15.3%), CT (‒18.2%), SM (‒10.3%), CSMI (‒6.4%), and CSI (‒10.8%) significantly decreased (all p < 0.001). The prevalence of osteoporosis in the lumbar spine, femoral neck, and total hip was, respectively, 82%, 81%, and 65% in fracture patients. Cox proportional hazard model analysis showed that in the age adjusted model, the fracture hazard ratio (HR) of CSA, CT, BR, SM, and CSI significantly increased (HRs = 1.60‒8.33; 95% CI = 1.08‒16.6; all p < 0.001). In the model adjusted for age and femoral neck BMD, HRs of CT (HRs = 3.90‒8.03; 95% CI = 2.45‒15.1; all p < 0.001) and BR (HRs = 1.62‒2.60; 95% CI = 1.20‒5.44; all p < 0.001) were still significantly increased. CONCLUSION: These results suggest that the majority of osteoporotic fractures of the femoral neck of native Chinese women occur in patients with osteoporosis. CT thinning or BR increase of FNGPs may be independent predictors of fragility fracture of femoral neck in native Chinese women unrelated to BMD.

Mechanical analysis of modified femoral neck system in the treatment of osteoporotic femoral neck fractures.

BACKGROUND: Despite the explicit biomechanical advantages associated with FNS, it is currently inconclusive, based on the existing literature, whether Femoral Neck System (FNS) outperforms Cannulated cancellous screws (CSS) in all aspects. Due to variances in bone morphology and bone density between the elderly and young cohorts, additional research is warranted to ascertain whether the benefits of FNS remain applicable to elderly osteoporosis patients. This study aimed to investigate the biomechanical properties of FNS in osteoporotic femoral neck fractures and propose optimization strategies including additional anti-rotation screw. METHODS: The Pauwels type III femoral neck fracture models were reconstructed using finite element numerical techniques. The CSS, FNS, and modified FNS (M-FNS) models were created based on features and parameterization. The various internal fixations were individually assembled with the assigned normal and osteoporotic models. In the static analysis mode, uniform stress loads were imposed on all models. The deformation and stress variations of the femur and internal fixation models were recorded. Simultaneously, descriptions of shear stress and strain energy were also incorporated into the figures. RESULTS: Following bone mass reduction, deformations in CSS, FNS, and M-FNS increased by 47%, 52%, and 40%, respectively. The equivalent stress increments for CSS, FNS, and M-FNS were 3%, 43%, 17%, respectively. Meanwhile, variations in strain energy and shear stress were observed. The strain energy increments for CSS, FNS, and M-FNS were 4%, 76%, and 5%, respectively. The shear stress increments for CSS, FNS, and M-FNS were 4%, 65% and 44%, respectively. Within the osteoporotic model, M-FNS demonstrated the lowest total displacement, shear stress, and strain energy. CONCLUSION: Modified FNS showed better stability in the osteoporotic model (OM). Using FNS alone may not exhibit immediate shear resistance advantages in OM. Concurrently, the addition of one anti-rotation screw can be regarded as a potential optimization choice, ensuring a harmonious alignment with the structural characteristics of FNS.

Femoral neck system versus multiple cannulated screws for the fixation of Pauwels classification type II femoral neck fractures in older female patients with low bone mass.

BACKGROUND: Femoral neck fractures in older adult patients are a major concern and often necessitate surgical intervention. This study compared the clinical outcomes of 2 surgical techniques: the femoral neck system (FNS) and cannulated compression screws (CCSs). METHODS: A total of 40 female patients (mean age 73.50 ± 11.55 years) with femoral neck fractures of Pauwels classification type II and receiving surgical fixation between 2020 and 2022 were enrolled. The patients were categorized into an FNS group (n = 12) or a CCS group (n = 28), and surgical duration, intraoperative blood loss, length of hospital stay, and incidence of postoperative adverse events were analyzed. RESULTS: No significant intergroup differences in demographic characteristics were discovered. The mean surgical duration for all patients was 52.88 ± 22.19 min, with no significant difference between the groups. However, the FNS group experienced significantly higher intraoperative blood loss (P = 0.002) and longer hospital stay (P = 0.023) than did the CCS group. The incidence of osteonecrosis was higher in the CCS group, whereas the incidence of nonunion or malunion was higher in the FNS group. The surgical method did not appear to be a significant risk factor. The main risk factor for revision surgery was longer duration until the first adverse event (P = 0.015). CONCLUSION: The FNS does not appear to provide superior surgical outcomes compared with CCSs in older adult women with Pauwels classification type II femoral neck fractures. A longer duration between surgical fixation and the first adverse event before stabilization of the fracture site may be a risk factor for revision surgery.

Comparative analysis of the femoral neck system (FNS) vs. cannulated cancellous screws (CCS) in the treatment of Middle-aged and elderly patients with femoral neck fractures: clinical outcomes and biomechanical insights.

PURPOSE: This study aimed to compare the clinical outcomes and differences in biomechanical characteristics between the femoral neck system (FNS) and cannulated cancellous screws (CCSs) in the treatment of femoral neck fractures. METHODS: This study retrospectively analysed a cohort of 38 registered cases of femoral neck fractures treated surgically with either the FNS (n = 17) or CCSs (n = 21) between January 2020 and December 2023. Indicators such as fluoroscopy frequency, length of hospital stay, and fracture healing time were compared between the two groups. Functional status was evaluated via the Harris hip score (HHS) and visual analogue scale (VAS), whereas prognosis was assessed based on changes in the neck shaft angle and femoral neck shortening. Additionally, six sets of femoral neck fracture models were developed based on Pauwels angles of 30°, 40°, 50°, 60°, 70°, and 80°. Two experimental groups, FNS and CCS, were established, and a joint reaction force of 1800 N was applied to the proximal femur. The displacement, stress, and stiffness of the components of interest in the different models were tested and compared. RESULTS: The distributions of all the baseline characteristics were similar between the two groups (p > 0.05). The FNS group presented significantly shorter fluoroscopy frequency, length of hospital stay, and fracture healing time (p < 0.05). Harris and VAS scores were higher in the FNS group than in the CCS group (p < 0.05). Postoperative changes in the neck shaft angle and femoral neck shortening were significantly lower in the FNS group than in the CCS group (p < 0.05). The results of the finite element analysis indicated that the maximum stress on the femoral head and varus angle were generally lower in the FNS group than in the CCS group and that the maximum displacement of the femoral head and FNS was generally lower in the FNS group than in the CCS group. However, the superiority of FNS over CCS decreased with increasing Pauwels angle. Additionally, the effectiveness of FNS in limiting displacement of the femoral neck upper wall was not as favourable as that of CCS. CONCLUSIONS: The treatment of femoral neck fractures with FNS is superior and contributes to improved hip joint function. Biomechanical research has confirmed its structural stability and advantages in resisting femoral head varus. However, challenges to its fixation efficacy persist, particularly at higher Pauwels angles.

Comparison of rehabilitation outcomes between robot-assisted and freehand screw placement in treatment of femoral neck fractures: a systematic review and meta-analysis.

PURPOSE: To compare the postoperative rehabilitation of femoral neck fractures treated with robot-assisted nailing and freehand nailing. METHODS: We systematically searched the PubMed, EMBASE, Cochrane, China National Knowledge Infrastructure(CNKI), WanFang database, China Science and Technology Journal Database (VIP) and Web of Science databases to identify potentially eligible articles. Indispensable data such as the year of publication, country, study type, robot type, age, number of patients, sex distribution, study design, and outcome indicators were extracted. The outcome indicators of interest included healing rate, length of healing time, Harris score, operation time, frequency of X-ray fluoroscopy, frequency of guide pin insertion, and intraoperative blood loss. RevMan 5.4.1 was used for the meta-analysis. RESULTS: Fourteen studies with 908 participants were included in this meta-analysis. The results showed that in terms of healing rate (SMD = 2.75, 95% CI, 1.03 to 7.32, P = 0.04) and Harris score (SMD = 2.27, 95% CI, 0.79 to 3.75, P = 0.003), robot-assisted screw placement technique scores were higher than the traditional freehand technique. Additionally, operative time (SMD = -12.72, 95% CI, -19.74 to -5.70, P = 0.0004), healing time (SMD = -13.63, 95% CI, -20.18 to -7.08, P < 0.0001), frequency of X-ray fluoroscopy (SMD = - 13.64, 95% CI, - 18.32 to - 8.95, P < 0.00001), frequency of guide pin insertion (SMD = - 7.95, 95% CI, - 10.13 to - 5.76, P < 0.00001), and intraoperative blood loss (SMD = - 17.33, 95% CI, - 23.66 to - 11.00, P < 0.00001) were lower for patients who underwent robotic-assisted screw placement than those for patients who underwent the conventional freehand technique. CONCLUSION: Compared to the freehand nailing technique, robot-assisted nailing helps improve postoperative healing rates in patients with femoral neck fractures; shortens healing times; better restores hip function; reduces the number of intraoperative fluoroscopies, guides pin placements; reduces intraoperative bleeding; and increases perioperative safety.

The significance of reduction of valgus-intercalated femoral neck fracture with valgus angle > 15°and the selection of internal fixation by finite element analysis.

BACKGROUND: Currently, consensus is lacking on the necessity of internal fixation after reducing valgus-intercalated femoral neck fractures with abduction > 15°. This study employs finite element analysis to compare the biomechanical differences between the femoral neck dynamic cross nail system (FNS) and inverted cannulated screw (ICS), aiming to provide a foundation for clinical procedures. METHODS: Human femur CT scan data were processed using MimICS21.0 and Geomagic 2021 software, imported into Solidworks2021 to create fracture models, based on Garden I abduction and Valgus-intercalated femoral neck fractures. The internal fixation model was divided into two groups: A-Anatomic reduction group; B-Valgus-intercalated femoral neck fracture group. ANSYS software facilitated meshing, material assignment, and data calculation for stress and displacement comparisons when ICS and FNS were applied in reduction or non-reduction scenarios. RESULTS: Without internal fixation, peak femur stress in both groups was 142.93 MPa and 183.62 MPa. Post FNS fixation, peak stress was 254.11 MPa and 424.81 MPa; peak stresses for the two FNS models were 141.26 MPa and 248.33 MPa. Maximum displacements for the two FNS groups were 1.91 mm and 1.26 mm, with peak fracture-end stress at 50.751 MPa and 124.47 MPa. After ICS fixation, femur peak stress was 204.76 MPa and 274.08 MPa; maximum displacements were 1.53 mm and 1.15 mm. ICS peak stress was 123.88 MPa and 174.61 MPa; maximum displacements were 1.17 mm and 1.09 mm, with peak fracture-end stress at 61.732 MPa and 104.02 MPa, respectively. CONCLUSIONS: Our finite element study indicates superior mechanical stability with internal fixation after reducing valgus-intercalated femoral neck fractures (> 15°) compared to in situ fixation. Additionally, ICS biomechanical properties are more suitable for this fracture type than FNS.

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.

Application of robot navigation system for insertion of femoral neck system in the treatment of femoral neck fracture.

PURPOSE: To evaluate the short-term clinical efficacy and advantages of surgery robot positioning system for insertion of Femoral Neck System (FNS) in the treatment of femoral neck fractures. METHODS: The clinical data of 52 patients with Femoral neck fracture (FNF) who had been treated with FNS between June 2020 and September 2021 were retrospectively analyzed. Among them, 26 patients were treated with traditional FNS (control group), while 26 additional patients were treated with FNS assisted by an orthopaedic robot positioning system (study group). The operation duration, frequency of key-guide needle placement, intraoperative blood loss, incision length, fracture healing rate, fracture healing time, and the Harris scores at the last follow-up were calculated and compared between the 2 groups. RESULTS: The study group had shorter operation duration, fewer numbers of placing the key-guide needle, less intraoperative blood loss, and smaller surgical incisions than the control group (all, P < 0.05). There was no significant difference in the rate of fracture healing rate between the 2 groups (P = 0.47), while the fracture healing duration of the study group was shorter than that of the control group (P = 0.03). At the last follow-up, compared with the control group, the Harris score and the number of excellent and good ratings were significantly higher in the study group (all, P < 0.05). CONCLUSIONS: Using orthopaedic surgery robot positioning system-assisted FNS in the treatment of FNFs can effectively improve the efficiency of surgery, shorten operation time, and reduce the number of placing the key-guide needle, intraoperative blood loss, and operative trauma. Simultaneously, it shortens the duration of fracture healing and improves the recovery of hip function.

The small screw-apex distance is potentially associated with femoral head osteonecrosis in adults with femoral neck fractures treated by closed reduction and percutaneous 3 parallel cannulated screws.

OBJECTIVE: Femoral neck fractures (FNFs) are among the most common fractures in elderly individuals. Surgery is the main treatment for FNFs, and osteonecrosis of the femoral head (ONFH) is one of the unacceptable complications. This study aimed to assess both the clinical and radiological outcomes in patients with FNFs treated with three parallel cannulated screws and to identify relationship between screws position and ONFH. PATIENTS AND METHODS: A total of 100 patients who were treated with closed reduction and fixed with 3 parallel cannulated screws met the inclusion criteria between January 2014 and December 2020 at authors' institution. The follow-up duration, age, sex, affected side, and injury-to-surgery interval were collected; the neck-shaft angle of both hips, screw-apex distance (SAD) and the tip-apex distance (TAD)were measured; and the Garden classification, quality of reduction and presence of ONFH were evaluated. RESULTS: The sample consisted of 37 males and 63 females, with 60 left and 40 right hips affected. The mean age of patients was 54.93 ± 12.24 years, and the mean follow-up was 56.3 ± 13.38 months. The overall incidence of ONFH was 13%. No significant difference was observed in the incidence of ONFH by affected side, age, fracture displacement, injury-to-surgery interval, neck-shaft angle deviation, or reduction quality. The SAD was significantly shorter in ONFH patients than in normal patients for all three screws (p = 0.02, 0.02, and 0.01, respectively). CONCLUSIONS: The short SAD of all screws is associated with femoral head necrosis of FNFs treated with 3 cannulated screws. The short SAD indicated that screws malpositioning in the weight-bearing area of the femoral head, potentially harming the blood supply and compromising the anchorage of the primary compressive trabeculae in this region.

Comparison of acute outcomes from elective total hip replacements and after fragility femoral neck fractures in nonagenarians.

BACKGROUND: Hip hemiarthroplasty has traditionally been used to treat displaced femoral neck fractures in older, frailer patients whilst total hip replacements (THR) have been reserved for younger and fitter patients. However, not all elderly patients are frail, and some may be able to tolerate and benefit from an acute THR. Nonagenarians are a particularly heterogenous subpopulation of the elderly, with varying degrees of independence. Since THRs are performed electively as a routine treatment for osteoarthritis in the elderly, its safety is well established in the older patient. The aim of this study was to compare the safety of emergency THR to elective THR in nonagenarians. METHODS: A retrospective 10-year cohort study was conducted using data submitted to the National Hip Fracture Database (NHFD) across three hospitals in one large NHS Trust. Data was collected from 126 nonagenarians who underwent THRs between 1st January 2010 - 31st December 2020 and was categorised into emergency THR and elective THR groups. Mortality rates were compared between the two groups. Secondary outcomes were also compared including postoperative complications (dislocations, revision surgeries, and periprosthetic fracture), length of stay in hospital, and discharge destination. RESULTS: There was no significant difference in mortality between the two groups, with 1-year mortality rates of 11.4% and 12.1% reported for emergency and elective patients respectively (p = 0.848). There were no significant differences in postoperative complication rate and discharge destination. Patients who had emergency THR spent 5.56 days longer in hospital compared to elective patients (p = 0.015). CONCLUSION: There is no increased risk of 1-year mortality in emergency THR compared to elective THR, in a nonagenarian population. Therefore, nonagenarians presenting with a hip fracture who would have been considered for a THR if presenting on an elective basis should not be precluded from an emergency THR on safety grounds. TRIAL REGISTRATION: Not necessary as this was deemed not to be clinical research, and was considered to be a service evaluation.

Morphological characteristics of femoral neck fractures in young and middle-aged population: a retrospective descriptive study.

BACKGROUND: A understanding of morphological characteristics are important to femoral neck fractures (FNFs) resulting in high rates of complications in the young and middle-aged adults and the detailed data is lack in the literature. We aimed to report on the detailed morphological characteristics and the relationship between them in young and middle-aged adults with femoral neck fractures (FNFs). METHODS: The postoperative CT images of one hundred and fifty-two adults with FNFs were retrospectively reviewed. After image standardization, morphological characteristics including fracture orientation, cortex comminution, and intraosseous bone defects were measured and analyzed. Additionally, the distribution and correlation of these morphological features were analyzed using Pauwels classification, the right angle of the neck axis (VNA) classification, and the anteromedial oblique angle (AMA). RESULTS: Pauwels III fractures accounted for approximately half (55.2%) of the FNFs analyzed. Pauwels II and III could be detected in all four VNA types, and the distribution of the Pauwels types in VNA classification showed significant differences (χ2 = 106.363, p < 0.001). The VNA (9.0° ± 12.1) showed positive correlation with the neck-shaft angle (139.5° ± 6.3) and modified Pauwels angle (49.8° ± 10.6) (r = 0.441, r = 0.855, all p < 0.001). Cortical comminutions were commonly observed in the posterior (86.7%) and the inferior (80.7%). AMAs within the cases without posterior and inferior cortex comminutions were significantly larger than those with comminution (t = 2.594, 2.1196; p = 0.01, 0.036), but no difference could be detected after the AMA being divided into three groups (< 85°, 85°-95°, > 95°). The MPA, VNA and AMA of the group with an intraosseous defect were significantly different compared with those without (t = 2.847, 2.314, 2.268; p = 0.005, 0.022,0.025). The incidence of intraosseous defects within the groups with coronal and axial cortex comminutions were significantly higher than those within the groups without comminutions (χ2 = 34.87, 25.303; p < 0.001). CONCLUSIONS: The present study highlights the morphological diversity and complexity within FNFs in young and middle-aged adults, which allows for more accurate simulation of FNF patterns in the future biomechanical studies.

Insufficient stem antetorsion and lower cup abduction is a combined risk factor for posterior hip dislocation in patients undergoing THA for femoral neck fractures: a retrospective analysis.

BACKGROUND: The role of acetabular and femoral component positions with respect to the risk of post-operative instability and dislocation remains debated. In this study, we aimed to identify potential risk factors for early dislocation following primary total hip arthroplasty (THA) for displaced intracapsular femoral neck fractures (FNF) using radiological measurements. METHODS: We retrospectively analyzed data for patients who underwent cementless primary THA for FNF using a posterolateral approach between January 2018 and December 2021. Follow-up duration, age, sex, affected side, and mean time from THA to dislocation were recorded. Leg-length inequality, abductor lever arm, vertical and horizontal femoral offsets, vertical and horizontal hip centers of rotation, abduction, anteversion of the acetabulum and femoral prosthesis, and combined anteversion were measured. RESULTS: The study sample included 17 men and 34 women, with 21 and 30 patients undergoing left- and right-hip operations, respectively. The mean patient age was 70.18 ± 7.64 years, and the mean follow-up duration was 27.73 ± 13.52 months. The mean time between THA and dislocation was 1.58 ± 0.79 months. Seven patients (13.73%) sustained posterior dislocation of the hip. The abduction angle (36.05 ± 6.82° vs. 45.68 ± 8.78°) (p = 0.008) and anteversion of the femoral prosthesis (8.26 ± 4.47° vs. 19.47 ± 9.01°) (p = 0.002) were significantly lower in the dislocation group than in the control group. There were no significant differences in other parameters. CONCLUSIONS: Insufficient stem antetorsion combined with lower abduction angle of the acetabular component were associated with a high risk of dislocation, especially in patients with deep flexion or internal rotation of the flexed hip joint and knees, or in patients with a stiff spine or anterior pelvic tilt, impingement may then occur in the neck of the prosthesis and cup component, ultimately resulting in posterior dislocation. These findings could remind surgeons to avoid simultaneous occurrence of both in THA surgery. These results provide new insight into risk factors for hip dislocation in patients undergoing primary THA for FNF and may aid in reducing the risk of instability and dislocation. LEVEL OF EVIDENCE: Prospective comparative study Level II.