Objective:To study the anti-inflammatory mechanism of acupoint acupuncture combined with tetramethylpyrazine in regulating the nuclear factor kappa B (NF-κB)/NOD like receptor thermal protein domain associated protein 3 (NLRP3) signaling pathway in a T-2 toxin induced rat model of Kashin-Beck disease.Methods:A total of 40 clean-grade Sprague-Dawley (SD) rats (half male and half female), weighing 180 - 220 g, were divided using a random number table method into model group, tetramethylpyrazine group, acupoint acupuncture combined with tetramethylpyrazine group, and control group, with 10 rats in each group. Rats in the model group, the tetramethylpyrazine group, and the acupoint acupuncture combined with tetramethylpyrazine group were intraperitoneally injected with 1.5 mg/kg of 0.1% T-2 toxin five times per week for 4 consecutive weeks. Rats in both the tetramethylpyrazine group and the acupoint acupuncture combined with tetramethylpyrazine group were intraperitoneally injected with 100 mg·kg -1·d -1 tetramethylpyrazine solution. Meanwhile, rats in the model group and the control group were administered an equivalent volume of physiological saline for consecutive 4 weeks. Acupoint acupuncture combined with tetramethylpyrazine group was used to needle the bilateral "Qu Chi" and "Wei Zhong" of rats with a diameter of 3 - 5 mm, leaving the needle for 20 minutes, once a day, for 4 weeks. After the last injection, the rats were euthanized to collect blood samples and knee joint cartilage. Hematoxylin and eosin staining was performed to observe the pathological changes in the knee joint cartilage of rats. Enzyme-linked immunosorbent assay (ELISA) was used to measure serum levels of osteocalcin (OC), alkaline phosphatase (ALP), β-carboxy-terminal cross-linked telopeptide of type Ⅰ collagen (β-CTX), interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α). Western blot analysis was used to determine protein expression levels of NF-κB p65 and NLRP3. Results:In the control group, intact cartilage surface, middle, and deep structures were observed in the knee joint cartilage of rats. In the model group, pathological changes similar to adult Kashin-Beck disease were observed in the knee joint cartilage. The integrity of the knee joint cartilage of rats in the tetramethylpyrazine group and the acupoint acupuncture combined with tetramethylpyrazine group was significantly improved compared to the model group. Compared with the control group, the levels of OC and ALP in the serum of the model group rats were significantly reduced, while the level of β-CTX was significantly increased ( P < 0.05). Compared with the model group, the levels of OC and ALP in the serum of rats in the tetramethylpyrazine group and the acupoint acupuncture combined with tetramethylpyrazine group were significantly increased, while the levels of β-CTX were significantly decreased ( P < 0.05). The levels of OC and ALP in the serum of rats in the acupoint acupuncture combined with tetramethylpyrazine group were higher than those in the tetramethylpyrazine group, while the level of β-CTX was lower than that in the tetramethylpyrazine group ( P < 0.05). Compared with the control group, the levels of IL-1β, IL-6 and TNF-α in the serum of the model group rats were significantly increased ( P < 0.05). Compared with the model group, the levels of IL-1β, IL-6 and TNF-α in the serum of rats in the tetramethylpyrazine group and the acupoint acupuncture combined with tetramethylpyrazine group were significantly reduced ( P < 0.05). The levels of IL-1β, IL-6 and TNF-α in the serum of rats in the acupoint acupuncture combined with tetramethylpyrazine group were lower than those in the tetramethylpyrazine group ( P < 0.05). Compared with the control group, the expression levels of NF-κB p65 and NLRP3 proteins in the model group rats were significantly increased ( P < 0.05). Compared with the model group, the expression levels of NF-κB p65 and NLRP3 proteins were significantly reduced in the tetramethylpyrazine group and the acupoint acupuncture combined with tetramethylpyrazine group ( P < 0.05). The expression levels of NF-κB p65 and NLRP3 proteins in the acupoint acupuncture combined with tetramethylpyrazine group were significantly lower than those in the tetramethylpyrazine group ( P < 0.05). Conclusion:Acupoint acupuncture combined with tetramethylpyrazine has a good anti-inflammatory effect on T-2 toxin induced Kashin-Beck disease rats, and its mechanism may be related to the downregulation of NF-κB p65 and NLRP3 protein expression.

Objective To investigate the effect of postoperative reduction quality in femoral neck fracture internal fixation on mechanical properties of the femoral head from the perspective of trabecular bone biomechanics.Methods From patients who underwent hip replacement surgery for femoral neck fractures,a total of 26 femoral head slice specimens were obtained.The central axis of the primary compressive trabeculae was defined as the 0° group,with the intersection point of the primary compressive trabeculae and the femoral calcar serving as the center.By rotating the specimens to simulate different reduction angles,the cut femoral head slice specimens were randomly divided into five groups:-10°,-5°,0°,5°,and 10°,representing femoral heads with varying reduction qualities.The specimens were subjected to single compression load tests and fatigue load tests.The load was set from 70 N to 1 400 N,at a frequency of 1 Hz,with 10 000 cycles.Axial stiffness,displacement,and the number of collapse cycles were measured,to compare the biomechanical properties of femoral head specimens under different reduction qualities.Results There were differences in the axial stiffness,displacement,and number of collapse cycles among the femoral head specimens in different groups.Under 800 N load,the axial stiffness of 0° group was significantly greater than that of±10° groups(P＜0.05).The axial stiffness of 0° group was also greater than that of the±5° groups,but the differences were not statistically significant(P＞0.05).The axial stiffness of±5° groups was greater than that of±10° groups(P＜0.05).0° group had a lower displacement than±5° groups and±10° groups.However,the differences in displacement between 0° group and±5° groups were not statistically significant(P＞0.05),while the differences between the 0° group and±10° groups were statistically significant(P＜0.05).The differences in displacement between±5° groups and±10° groups were also statistically significant(P＜0.05).0° group had a significantly higher number of collapse cycles than±10° groups(P＜0.05).The number of collapse cycles in 0° group was also higher than that in±5° groups,but the differences were not statistically significant(P＞0.05).The number of collapse cycles in±5° groups was significantly higher than that±10° groups(P＜0.05).Conclusions The quality of reduction after internal fixation of femoral neck fractures significantly affects the biomechanical properties of the femoral head.This study provides a scientific basis for optimizing treatment and postoperative management,aiming to improve clinical outcomes and patients' quality of life.

Objective:To explore the degree of change in anteversion angle and related risk factors after intramedullary nail fixation of intertrochanteric femur fracture in the elderly.Methods:The data of 256 elderly patients who underwent intramedullary nail fixation for intertrochanteric fractures of the femur at Tianjin Hospital of Tianjin University from March 2020 to March 2023 were selected, including 114 males and 142 females, with an age of 75.40±10.69 years (range, 65-94 years). The degree of change in the anteversion angle of the affected hip before and after the surgery was measured by CT scan of the hip, the Receiver Operating Characteristic Curve (ROC) was plotted, the area under the ROC curve was analyzed, and the optimal degree of grouping was determined by calculating the Youden Index, then all the patients were divided into two groups. The correlation between various risk factors (age, sex, type of internal fixation, fracture AO type, quality of reduction, fracture medial cortical defect or not, cusp distance) and the change of anterior tilt angle was screened by univariate and multivariate logistic regression analyses.Results:All 256 patients were followed up for 20.7±2.1 months (range, 18-23 months). Anteversion on the healthy side was 12.68°±5.10° (range, 5°-28°); postoperative anteversion on the affected side was 15.04°±7.67° (range, 9°-36°). By comparing the difference in the anterior tilt angle between the affected side and the healthy side, it was found that the anterior tilt angle of 67 patients was completely restored to the healthy side level after the operation. The anteversion angle was enlarged in 131 cases, of which the mildly increased angle (1°-9°) was found in 106 cases, moderately increased (10°-15°) was found in 17 cases, and significantly increased (>15°) was found in 8 cases; 58 patients showed anteversion angle reduction, of which 45 cases were mildly reduced (1°-9°), 13 cases were moderately reduced (10°-14°). The area under the ROC curve for the patient's anteversion angle and its 95% CI were 0.714(0.559, 0.867), and the maximum value of its Youden Index was 0.221, which corresponded to the optimal critical angle of 4°. There was no statistically significant difference in age, gender, reduction quality or fracture AO classification between the group with an anteversion angle>4° and the group with an anteversion angle≤4° ( P>0.05). The types of internal fixation, medial cortical defect and insufficient tip apex distance (TAD) were included in the binary variable logistic regression analysis. The results showed that single-nail internal fixation [ OR=0.412, 95% CI(0.244, 0.695), P=0.007], medial cortical defect [ OR=0.471, 95% CI(0.279, 0.793), P=0.009] and TAD>25 mm [ OR=0.367, 95% CI(0.207, 0.651), P=0.003] are independent risk factors for changes in anteversion angle after intramedullary nail fixation of intertrochanteric femur fractures in elderly. Conclusion:Single-nail internal fixation, medial cortical defect and TAD >25 mm are independent risk factors for the change of anteversion angle after intramedullary nail internal fixation of intertrochanteric fractures in the elderly.

Objective:To evaluate the clinical effect of derotational distal femoral osteotomy (DDFO) combined with medial patellofemoral ligament (MPFL) reconstruction assisted by digital orthopedic technique in the treatment of recurrent patellar dislocation with enlarged femoral anteversion angle (FAA).Methods:TThe clinical data of 18 patients (4 men and 14 women; mean age 22.1±0.7 years; range, 18-26 years) with recurrent patellar dislocation (FAA≥30°) admitted to Digital Orthopedic Technology Clinical Application Center in Tianjin hospital from May 2022 to December 2023 were retrospectively analyzed. The average number of patella dislocations were 3.6±0.4 (range, 2-8 times), with a mean symptom duration of 4.3±0.4 years (range, 2-7 years). According to Dejour classification of femoral trochlea dysplasia, there were 5 cases of type A, 3 cases of type B, 6 cases of type C and 4 cases of type D. All patients underwent 3D CT scanning and digital modeling before operation. Based on the modeling results, personalized osteotomy and orthopedic integration guide were designed and printed to direct intraoperative DDFO and MPFL reconstruction. Radiological parameters, knee function and complications were assessed during follow-up. Knee function assessments included visual analogue scale (VAS), Intemational Knee Documentation Committee Knee Form (IKDC), Kujala, Lysholm and Tegner score. The radiological parameters included FAA, patellar tilt angle (PTA), tibial tuberosity-trochlear groove distance (TT-TG) and caton-deschamps index (CDI).Results:All patients underwent surgery and were followed up for 15.4±2.8 months (range, 12-20 months). Complications occurred in 3 patients, including deep venous thrombosis in 2 cases and wound effusion in 1 case. No other complications such as wound infection, nerve injury, vascular injury, fracture nonunion or patella dislocation were recorded. The VAS score improved from 5.4±0.3 preoperatively to 2.1±0.2 at one year postoperatively. The IKDC score improved from 44.4±2.7 to 79.2±1.9 points. The Kujala score improved from 51.8±2.6 to 86.1±1.6, the Lysholm from 49.8±2.5 to 84.9±1.5, and the Tegner score from 2.2±0.2 to 4.1±0.2. The FAA decreased from 39.7°±1.2° to 14.9°±0.2°, the PTA from 33.1°±2.6° to 12.6°±1.4°, and the TT-TG from 20.2±0.6 to 13.9±0.4 mm. The differences between time of all the above-mentioned parameters were statistically significant ( P<0.05). The CDI remained stable, which changed from 1.03±0.02 preoperatively to 1.07±0.01 one year after operation ( P>0.05). Conclusions:After the application of DDFO combined with MPFL reconstruction assist by personalized osteotomy and orthopedic integrated guide, the patient's knee function and imaging parameters were significantly improved at one-year follow-up. In the treatment of recurrent patellar dislocation with enlarged FAA, good early clinical efficacy could be achieved with this operation.

Objective:To analyze the efficacy of phantom-less quantitative computer tomography (PL-QCT) for the diagnosis of osteoporosis in patients with lumbar degenerative diseases.Methods:From October 2021 to October 2023, a total of 1 248 patients with lumbar degenerative disease who did not receive anti-osteoporosis treatment in the Department of Spine Surgery, Tianjin Hospital were retrospectively analyzed. There were 520 males and 728 females, aged 62.31±9.37 years (range, 40-87 years), height 1.66±0.08 m (range, 1.43-1.89 m), weight 69.04±8.27 kg (range, 49-93 kg). The mean body mass index was 26.11±3.67 kg/m 2 (range, 14.40-37.11 kg/m 2). Dual-energy X-ray absorptiometry (DXA) and PL-QCT were used to diagnose osteoporosis, and the detection rates of the two diagnostic methods were compared. The receiver operating characteristic (ROC) curve of PL-QCT for the diagnosis of osteoporosis was drawn, the area under the curve (AUC) and 95% confidence interval (CI), sensitivity and specificity were calculated. Results:Among 1 248 patients with lumbar degenerative diseases, 626 (50.2%) were diagnosed as osteoporosis by PL-QCT, 423(33.9%) were diagnosed by spine DXA, 488(39.1%) were diagnosed by hip DXA and 539 patients(43.2%) were diagnosed by dual-site DXA. The detection rate of osteoporosis of PL-QCT was higher than that of spine DXA (χ 2=193.557, P<0.001), hip DXA (χ 2=322.201, P<0.001) and dual-site DXA (χ 2=94.683, P<0.001), and the difference was statistically significant. Taking the diagnostic results of spinal DXA for osteoporosis as a reference, the ROC curve of PL-QCT for the diagnosis of osteoporosis showed a sensitivity of 79%, a specificity of 81%, and an AUC and 95% CI of 0.82(0.79, 0.85). Taking the diagnostic results of hip DXA for osteoporosis as a reference, the ROC curve of PL-QCT for the diagnosis of osteoporosis showed a sensitivity of 85%, a specificity of 55%, and an AUC and 95% CI of 0.75(0.71, 0.78). Taking the diagnostic results of two-site DXA for osteoporosis as a reference, the ROC curve of PL-QCT for the diagnosis of osteoporosis showed a sensitivity of 72%, a specificity of 75%, and an AUC and 95% CI of 0.81(0.78, 0.83). Conclusion:Compared with DXA, PL-QCT has a higher detection rate of osteoporosis in patients with degenerative lumbar spine disease and good diagnostic efficacy.

Objective:To investigate the clinical efficacy of lumbar lateral interbody fusion (LLIF) versus posterior lumbar interbody fusion (PLIF) in the treatment of severe lumbar spinal stenosis.Methods:The data of patients with severe lumbar spinal stenosis who underwent LLIF or PLIF from February 2019 to December 2023 were retrospectively analyzed. There were 30 patients in the LLIF group, 10 males and 20 females, aged 62.7±5.6 years (range, 53-74 years), including 21 cases of single segment and 9 cases of double segment. There were 46 patients in the PLIF group, including 20 males and 26 females, aged 63.2±8.4 years (range, 43-75 years), 40 cases of single segment and 6 cases of double segment. The visual analogue scale (VAS), Oswestry disability index (ODI), intervertebral space height, intervertebral foramen height and postoperative complications were compared between the two groups.Results:All patients were followed up for an average of 21.3±6.4 months (range, 12-32 months). The intraoperative blood loss in the LLIF group was 112.2±76.9 ml, which was significantly lower than 193.9±88.2 ml in the PLIF group ( P<0.05). The VAS scores of back pain and leg pain after operation were significantly lower than those before operation in the two groups ( P<0.05). There was no statistically significant difference between groups in back pain VAS scores at preoperative, 6 months postoperative, and final follow-up ( P>0.05); the back pain VAS score at 1 month postoperatively in the LLIF group was 1.6±1.2, which was less than 2.8±0.7 in the PLIF group ( P<0.05). There was no statistically significant difference between groups in leg pain VAS scores at preoperative, 1 month postoperative, and 6 months postoperative ( P>0.05); the leg pain VAS score at the final follow-up in the LLIF group was 1.2±1.5, which was smaller than 1.8±1.0 in the PLIF group ( P<0.05). The postoperative ODI was smaller than the preoperative one in both groups, and the difference was statistically significant ( P<0.05); the preoperative, 1-month postoperative, 6-month postoperative, and final follow-up ODIs in the LLIF group were 45.7%±16.0%, 17.9%±12.0%, 16.2%±11.6%, and 15.7%±11.7%, and those in the PLIF group were 47.9%±15.4%, 20.1%±9.3%, 16.9%±10.6%, and 14.6%±11.0% in the PLIF group, and the difference between the groups was not statistically significant ( P>0.05). The preoperative intervertebral space height in the LLIF group was 10.6±2.0 mm, which was smaller than that in the PLIF group 11.8±2.2 mm ( P<0.05). The intervertebral space heights in the immediate postoperative period and at the final follow-up were 13.3±2.3 mm and 12.3±2.2 mm in the LLIF group and 13.7±1.7 mm and 13.0±1.9 mm in the PLIF group ( P>0.05). The preoperative intervertebral foraminal height in the LLIF group was 18.0±3.2 mm, which was smaller than that of 19.7±2.4 mm in the PLIF group ( P<0.05); the intervertebral foraminal heights in the immediate postoperative period and at the final follow-up were 21.4±2.5 mm and 20.2±2.4 mm in the LLIF group, and in the PLIF group were 20.7±2.4 mm and 19.7±2.6 mm in the PLIF group ( P>0.05). In the LLIF group, 2 cases had femoral nerve injury and 2 cases had transient back pain after operation. There were 2 cases of cerebrospinal fluid leakage, 1 case of screw loosening, and 2 cases of deep vein thrombosis in the PLIF group. In the PLIF group, 2 patients underwent revision, including 1 case due to cage displacement and 1 case due to screw malposition. The fusion settling rate was 21% (8/39) in the LLIF group and 12% (6/52) in the PLIF group ( P>0.05). Conclusion:Both LLIF and PLIF can effectively restore the intervertebral height, improve the lumbar function and the symptoms of back and leg pain in the treatment of severe lumbar spinal stenosis.

Objective:To investigate the risk factors for complications following lateral lumbar interbody fusion (LLIF) surgery.Methods:A retrospective analysis was conducted on 196 patients who underwent LLIF surgery via the psoas major muscle approach in the Department of Spinal Surgery, Tianjin Hospital, Tianjin University, from October 2018 to July 2024. The age, gender, body mass index (BMI), presence of hypertension, type 2 diabetes, heart disease, osteoporosis, history of lumbar surgery, history of abdominal surgery, history of abdominal inflammation, smoking status, operative time, surgical segments (whether the surgery was single-segment or multi-segments), and use of internal fixation or not were compared between patients with and without postoperative complications, the indicators with P<0.10 were included in the binary variable logistic regression analysis, and determine the independent risk factors for complications after LLIF surgery. Complications included anterior thigh symptoms (pain, numbness, weakness), cage subsidence, surgery-related complications (nerve injury, surgical site infection, postoperative buttock pain, urinary and fecal incontinence, etc.), and medical complications (cerebrovascular accident, deep vein thrombosis, urinary tract infection, etc.). Results:All 196 patients were followed up for 27.02 (12.6, 40.69) months. Postoperative complications occurred in 71 cases (96 times), and no complications occurred in 125 cases. In the complication group, there were 15 males and 56 females with a mean age of 61.82±7.57 years; in the non-complication group, there were 43 males and 82 females with a mean age of 62.00± 8.39 years. In the complication group, there were 43 cases of anterior thigh symptoms, 38 cases of cage subsidence, 11 cases of surgical operation-related complications, and 4 cases of medical complications. There were statistically significant differences in gender (χ 2=3.829, P=0.051), operation time ( t=2.391, P=0.018), and surgical segment (χ 2=4.245, P=0.039) between the complication group and the non-complication group. No statistically significant differences were found in age, gender, BMI, presence of hypertension, type 2 diabetes, heart disease, osteoporosis, history of lumbar surgery, history of abdominal surgery, history of abdominal inflammation, smoking status, or use of internal fixation ( P>0.10). Binary variable logistic regression analysis indicated that prolonged operative time [ OR=1.007, 95% CI(1.001, 1.013), P=0.019] and multilevel surgery [ OR=2.099, 95% CI(1.095, 4.025), P=0.026] were independent risk factors for complications following LLIF. Conclusion:Prolonged operative time and multi-segments surgery are independent risk factors for complications following LLIF.

Objective:To evaluate the clinical efficacy of 3D-printed patient-specific instrument (PSI) in assisting high tibial osteotomy (HTO).Methods:Clinical studies on 3D-printed PSI-assisted HTO were retrieved from various databases, including China National Knowledge Infrastructure (CNKI), Wanfang Data Knowledge Service Platform, VIP, the Chinese Medical Journal Full-text Database, PubMed, Embase, and Web of Science. Key data extracted included the hip-knee-ankle (HKA) angle, weight-bearing line (WBL) ratio, mechanical medial proximal tibial angle (MPTA), number of intraoperative fluoroscopies, and operation time. Studies were categorized into a PSI group (using 3D-printed PSI for osteotomy) and a non-PSI group (without 3D-printed PSI assistance). Comparisons were made between pre- and post-operative radiographic improvements in the PSI group, as well as differences between post-operative outcomes and pre-operative planned values. Additionally, the number of fluoroscopies and operation time were compared between the PSI and non-PSI groups. Meta-analysis was performed using Stata 12.0 statistical softwar.Results:A total of 30 studies were included in the meta-analysis. The results indicated that in the PSI group, the post-operative WBL ratio [ WMD=-39.66, 95% CI(-43.19, -36.12), P<0.001], HKA [ WMD=-8.85, 95% CI(-10.17, -7.52), P<0.001], and MPTA [ WMD=-8.65, 95% CI(-9.61, -7.68), P<0.001] were significantly smaller compared to pre-operative values. However, there were no significant differences between the post-operative values and pre-operative planned values for the WBL ratio [ WMD=0.74, 95% CI(-0.17, 1.66), P=0.112], HKA [ WMD=0.20, 95% CI(-0.05, 0.45), P=0.116], or MPTA [ WMD=0.22, 95% CI(-0.04, 0.48), P=0.147] in the PSI group. Furthermore, the operation time [ WMD=-14.04, 95% CI(-17.66, -10.42), P<0.001] and the number of fluoroscopies [ WMD=-9.33, 95% CI(-12.36, -6.30), P<0.001] were significantly lower in the PSI group compared to the non-PSI group. Conclusion:3D-printed PSI-assisted HTO enhances precision, reduces operation time, and minimizes the number of intraoperative fluoroscopies.

Objective:This study aims to explore clinical subtypes of Garden typeⅠfemoral neck fractures and develop corresponding reduction strategies based on the characteristics of the fractures.Methods:A retrospective analysis was conducted on the data of 256 patients with Garden type I femoral neck fractures admitted to Tianjin Hospital from January 2015 to January 2018. There were 89 males and 167 females included, with a mean age of 56.5±12.8 years (range, 17-86 years), and with 159 on the left side and 97 on the right side. According to the anteroposterior and lateral X-ray images, the fractures were further classified into two subtypes: 111 cases of Garden type I a (simple abduction without hypsokinesis of the femoral head), characterized by abduction and impaction of the femoral head on anteroposterior images, and no obvious hypsokinesis of the femoral head or only central impaction of the femoral head on lateral images; 145 cases of Garden I b type (femoral head abduction with hypsokinesis), characterized by abduction and impaction of the femoral head on anteroposterior images, and remarkable hypsokinesis on lateral images. The injury mechanism of type I a involved abduction and impaction caused by the violent extension, abduction, and external rotation of the hip joint. Mild flexion and adduction of the hip joint can be used to reduce the abduction and impaction. The injury mechanism of type I b is similar to type Ia in the first stage, but the violence continues to increase and leading to significant hypsokinesis of the femoral head. Reduction was achieved by excessive flexion, adduction, and mild internal rotation, tilting the femoral head backward to facilitate reduction. The surgical strategy were close reduction and cannulated screw fixation (three cannulated screws in an "inverted triangle" arrangement). Postoperatively, anteroposterior and lateral X-rays were taken immediately to assess the quality of reduction, including the Garden index, Lowell "S" curve, and screw placement. During follow-up, fracture healing and complications were recorded, and Harris score was used to evaluate hip joint function at the final follow-up.Results:All patients successfully received operative therapy and were followed up with a mean of 7.1±1.9 years (range, 5-10 years). Garden index showed 91.4%(234/256) achieved anatomical reduction, with an excellent reduction rate of 97.3%(249/256). The excellent rate of the Lowell "S" curve was 97.7%(250/256), and the excellent and good rate for screw insertion was 98.8%(253/256). All patients achieved primary fracture healing without infection, nonunion of fractures, failure of internal fixation, or other complications. Two patitents with Garden I b fractures (0.8%) developed femoral head necrosis due to premature weight-bearing at 9 and 12 months postoperatively, respectively, after fracture healing. However, with strict hip preservation treatment, their symptoms resolved without further progression of necrosis or need for reoperation. At the final follow-up, the mean Harris score was 93.9±4.5 points (range, 81-100 points), with an excellent and good rate of 98.8%(253/256).Conclusions:Garden I femoral neck fractures can be categorized into two subtypes based on their characteristics and injury mechanisms. Adopting corresponding reduction methods according to subtypes can achieve anatomical reduction and favorable early to mid-stage therapeutic outcomes (primary fracture healing and low incidence of femoral head necrosis).

Objective:To explore the degree of change in anteversion angle and related risk factors after intramedullary nail fixation of intertrochanteric femur fracture in the elderly.Methods:The data of 256 elderly patients who underwent intramedullary nail fixation for intertrochanteric fractures of the femur at Tianjin Hospital of Tianjin University from March 2020 to March 2023 were selected, including 114 males and 142 females, with an age of 75.40±10.69 years (range, 65-94 years). The degree of change in the anteversion angle of the affected hip before and after the surgery was measured by CT scan of the hip, the Receiver Operating Characteristic Curve (ROC) was plotted, the area under the ROC curve was analyzed, and the optimal degree of grouping was determined by calculating the Youden Index, then all the patients were divided into two groups. The correlation between various risk factors (age, sex, type of internal fixation, fracture AO type, quality of reduction, fracture medial cortical defect or not, cusp distance) and the change of anterior tilt angle was screened by univariate and multivariate logistic regression analyses.Results:All 256 patients were followed up for 20.7±2.1 months (range, 18-23 months). Anteversion on the healthy side was 12.68°±5.10° (range, 5°-28°); postoperative anteversion on the affected side was 15.04°±7.67° (range, 9°-36°). By comparing the difference in the anterior tilt angle between the affected side and the healthy side, it was found that the anterior tilt angle of 67 patients was completely restored to the healthy side level after the operation. The anteversion angle was enlarged in 131 cases, of which the mildly increased angle (1°-9°) was found in 106 cases, moderately increased (10°-15°) was found in 17 cases, and significantly increased (>15°) was found in 8 cases; 58 patients showed anteversion angle reduction, of which 45 cases were mildly reduced (1°-9°), 13 cases were moderately reduced (10°-14°). The area under the ROC curve for the patient's anteversion angle and its 95% CI were 0.714(0.559, 0.867), and the maximum value of its Youden Index was 0.221, which corresponded to the optimal critical angle of 4°. There was no statistically significant difference in age, gender, reduction quality or fracture AO classification between the group with an anteversion angle>4° and the group with an anteversion angle≤4° ( P>0.05). The types of internal fixation, medial cortical defect and insufficient tip apex distance (TAD) were included in the binary variable logistic regression analysis. The results showed that single-nail internal fixation [ OR=0.412, 95% CI(0.244, 0.695), P=0.007], medial cortical defect [ OR=0.471, 95% CI(0.279, 0.793), P=0.009] and TAD>25 mm [ OR=0.367, 95% CI(0.207, 0.651), P=0.003] are independent risk factors for changes in anteversion angle after intramedullary nail fixation of intertrochanteric femur fractures in elderly. Conclusion:Single-nail internal fixation, medial cortical defect and TAD >25 mm are independent risk factors for the change of anteversion angle after intramedullary nail internal fixation of intertrochanteric fractures in the elderly.