Objective:To compare the biomechanical stability of a novel interlocking intramedullary nail (nIMN) with that of a traditional interlocking intramedullary nail (tIMN) in the treatment of type AO 32-A3 femoral shaft fractures using a finite element analysis.Methods:A healthy adult male volunteer, aged 30 years old and weighing 70 kg, was selected for collection of his CT scan data of the femur. A three-dimensional finite element model of the femur was established using software Mimics 17.0 and Geomagic Studio. After femoral shaft fractures of AO/OTA types 32-A3a, 32-A3b, and 32-A3c were simulated, nIMN and tIMN were assembled respectively. After boundary conditions and material properties of the models were set based on reference literature, 4 load states were simulated: vertical standing, slow walking, fast walking, and descending stairs. The displacements and stress distribution at the femoral fracture ends under the same conditions were compared between nIMN and tIMN schemes of fixation. The stabilities of each fracture model at different fixation schemes and load states were analyzed.Results:In the 4 load states simulated, the displacements of the fracture ends averaged 0.129 mm, and the maximum stresses 111.00 MPa. The smallest displacement and maximum stress (0.014 mm and 29.48 MPa) were found in the vertical standing in the femoral shaft fracture of type 32-A3c fixed with nIMN. The largest displacement and maximum stress (0.325 mm and 242.98 MPa) were found in descending stairs in the femoral shaft fracture of type 32-A3a fixed with tIMN. In femoral shaft fractures of types 32-A3a, 32-A3b, and 32-A3c, regardless of tIMN or nIMN fixation, the displacement and maximum stress increased with the load, with the femoral shaft fracture of type 32-A3a being particularly evident. nIMN fixation resulted in lower displacements and maximum stresses in AO/OTA types 32-A3a, 32-A3b, and 32-A3c than tIMN fixation. Taking descending stairs as an example, the overall maximum stress occurred on the proximal part of the femur and the surrounding area of Adams'arc, with the maximum stress fluctuating between 86.62 and 242.98 MPa. The maximum stress at the fracture end fluctuated between 0.44 and 56.49 MPa. The stress mainly concentrated on the medial part, and decreased from type 32-A3a to type 32-A3b to type 32-A3c.Conclusion:In type AO 32-A3 femoral shaft fractures, nIMN leads to a smaller fracture end displacement and a lower maximum stress than tIMN, indicating better rotational stability.

Objective:To investigate the impact of sliding distance of the fmoral neck system (FNS) on the curative efficacy of displaced femoral neck fractures.Methods:A retrospective study was conducted to analyze the clinical data of the 179 patients with displaced femoral neck fracture who had been treated by FNS fixation at Department of Orthopaedics, The Second General Hospital of Fuzhou between September 2019 and September 2023. Based on the FNS sliding distance measured on X-ray films on the day after surgery or one day after surgery, the patients were assigned into 2 groups: a short sliding distance group [sliding distance ≤5 mm, n=55; 35 males, 20 females; median age: 50.0 (34.0, 59.0) years; body mass index (BMI): (24.0±2.4) kg/m 2] and a long sliding distance group [5 mm 0.05). At postoperative 3, 6, and 12 months, the distances of femoral neck shortening in the short sliding distance group [2.5 (0.7, 3.5) mm, 2.6 (0.7, 3.5) mm, and 2.7 (0.7, 3.5) mm] were significantly shorter than those in the long sliding distance group [3.2 (1.3, 5.7) mm, 3.2 (1.3, 7.1) mm, and 3.2 (1.4, 7.1) mm] ( P<0.05). The incidence of moderate-to-severe shortening at one year after surgery in the long sliding distance group [26.6% (33/124)] was significantly higher than that in the short sliding distance group [3.6%(2/55)] ( P<0.05). No significant differences were found between the 2 groups in tip-apex distance, operation time, intraoperative blood loss, fracture reduction quality, fracture healing time, or incidence of complications ( P>0.05). At the last follow-up, the Harris Hip Score in the short sliding distance group [93.5 (88.7, 96.2) points] was significantly higher than that in the long sliding distance group [90.1 (82.9, 94.9) points] ( P<0.05). Conclusion:In the treatment of displaced femoral neck fractures with FSN fixation, compared with those with a long sliding distance, the patients with a short sliding distance demonstrate superior outcomes in postoperative femoral neck shortening and functional recovery of the hip, but no significant difference in the incidence of complications.

Objective:To compare the biomechanical stability of a novel interlocking intramedullary nail (nIMN) with that of a traditional interlocking intramedullary nail (tIMN) in the treatment of type AO 32-A3 femoral shaft fractures using a finite element analysis.Methods:A healthy adult male volunteer, aged 30 years old and weighing 70 kg, was selected for collection of his CT scan data of the femur. A three-dimensional finite element model of the femur was established using software Mimics 17.0 and Geomagic Studio. After femoral shaft fractures of AO/OTA types 32-A3a, 32-A3b, and 32-A3c were simulated, nIMN and tIMN were assembled respectively. After boundary conditions and material properties of the models were set based on reference literature, 4 load states were simulated: vertical standing, slow walking, fast walking, and descending stairs. The displacements and stress distribution at the femoral fracture ends under the same conditions were compared between nIMN and tIMN schemes of fixation. The stabilities of each fracture model at different fixation schemes and load states were analyzed.Results:In the 4 load states simulated, the displacements of the fracture ends averaged 0.129 mm, and the maximum stresses 111.00 MPa. The smallest displacement and maximum stress (0.014 mm and 29.48 MPa) were found in the vertical standing in the femoral shaft fracture of type 32-A3c fixed with nIMN. The largest displacement and maximum stress (0.325 mm and 242.98 MPa) were found in descending stairs in the femoral shaft fracture of type 32-A3a fixed with tIMN. In femoral shaft fractures of types 32-A3a, 32-A3b, and 32-A3c, regardless of tIMN or nIMN fixation, the displacement and maximum stress increased with the load, with the femoral shaft fracture of type 32-A3a being particularly evident. nIMN fixation resulted in lower displacements and maximum stresses in AO/OTA types 32-A3a, 32-A3b, and 32-A3c than tIMN fixation. Taking descending stairs as an example, the overall maximum stress occurred on the proximal part of the femur and the surrounding area of Adams'arc, with the maximum stress fluctuating between 86.62 and 242.98 MPa. The maximum stress at the fracture end fluctuated between 0.44 and 56.49 MPa. The stress mainly concentrated on the medial part, and decreased from type 32-A3a to type 32-A3b to type 32-A3c.Conclusion:In type AO 32-A3 femoral shaft fractures, nIMN leads to a smaller fracture end displacement and a lower maximum stress than tIMN, indicating better rotational stability.

Objective:To investigate the impact of sliding distance of the fmoral neck system (FNS) on the curative efficacy of displaced femoral neck fractures.Methods:A retrospective study was conducted to analyze the clinical data of the 179 patients with displaced femoral neck fracture who had been treated by FNS fixation at Department of Orthopaedics, The Second General Hospital of Fuzhou between September 2019 and September 2023. Based on the FNS sliding distance measured on X-ray films on the day after surgery or one day after surgery, the patients were assigned into 2 groups: a short sliding distance group [sliding distance ≤5 mm, n=55; 35 males, 20 females; median age: 50.0 (34.0, 59.0) years; body mass index (BMI): (24.0±2.4) kg/m 2] and a long sliding distance group [5 mm 0.05). At postoperative 3, 6, and 12 months, the distances of femoral neck shortening in the short sliding distance group [2.5 (0.7, 3.5) mm, 2.6 (0.7, 3.5) mm, and 2.7 (0.7, 3.5) mm] were significantly shorter than those in the long sliding distance group [3.2 (1.3, 5.7) mm, 3.2 (1.3, 7.1) mm, and 3.2 (1.4, 7.1) mm] ( P<0.05). The incidence of moderate-to-severe shortening at one year after surgery in the long sliding distance group [26.6% (33/124)] was significantly higher than that in the short sliding distance group [3.6%(2/55)] ( P<0.05). No significant differences were found between the 2 groups in tip-apex distance, operation time, intraoperative blood loss, fracture reduction quality, fracture healing time, or incidence of complications ( P>0.05). At the last follow-up, the Harris Hip Score in the short sliding distance group [93.5 (88.7, 96.2) points] was significantly higher than that in the long sliding distance group [90.1 (82.9, 94.9) points] ( P<0.05). Conclusion:In the treatment of displaced femoral neck fractures with FSN fixation, compared with those with a long sliding distance, the patients with a short sliding distance demonstrate superior outcomes in postoperative femoral neck shortening and functional recovery of the hip, but no significant difference in the incidence of complications.

Objective:To investigate the incidence of and risk factors for femoral neck shortening in young and middle-aged patients with displaced femoral neck fracture treated by a femoral neck system (FNS).Methods:A retrospective study was conducted to analyze the clinical data of 135 patients with displaced femoral neck fracture who had been treated by closed reduction and FNS internal fixation at Department of Orthopaedics, The Second Hospital of Fuzhou from December 2019 to December 2021. There were 85 males and 50 females, with an age of 51 (42, 57) years and a body mass index of 22.6 (20.9, 24.2) kg/m 2. According to the Garden classification, there were 29 cases of type Ⅲ and 106 cases of type Ⅳ. Femoral neck shortening was observed. The patients' gender, age, side of shortening, body mass index, fracture type, high-energy injury, time from injury to surgery, cortical comminution at the fracture end, reduction quality (Garden index), partial weight bearing time, complete weight bearing time, and functional evaluation (Harris score) were recorded for a univariate analysis. Multivariate logistic regression was used to analyze the influencing factors for moderate to severe shortening. Results:All the 135 patients were followed up for 17.2 (15.0, 20.2) months. Different degrees of femoral neck shortening happened in all patients, yielding an incidence of 100%(135/135). The femoral neck shortening was 4.2 (2.6, 7.7) mm in displaced femoral neck fractures fixated by FNS. The shortening continued to worsen within the first 3 months after operation, reaching a stable state in the first 6 months. Persistent shortening hardly occurred after 6 months. According to the shortening distance, the patients were divided into a mild shortening group (76 cases <5 mm) and a moderate to severe shortening group (59 cases ≥ 5 mm). The Harris score at the last follow-up in the mild shortening group (91.7 ± 2.3) was significantly higher than that in the moderate to severe shortening group (87.9 ± 3.8) ( P<0.001). The fracture healing rate was 98.7% (75/76) in the mild shortening group and 98.3% (58/59) in the moderate to severe shortening group, showing no significant difference ( P=1.000). Logistic regression analysis found that the risk factors for moderate to severe shortening were fracture type (type Ⅳ) ( OR = 10.227, 95% CI: 1.845 to 56.693, P = 0.008), cortical comminution at the fracture end (if present) ( OR=52.697, 95% CI: 9.870 to 281.352, P<0.001), and partial weight bearing time <4 weeks ( OR = 0.168, 95% CI: 0.032 to 0.893, P = 0.036). Conclusions:The incidence of femoral neck shortening may be high in young and middle-aged patients with displaced femoral neck fracture treated by FNS, leading to decreased hip function. The main risk factors for femoral neck shortening are fracture type (Garden type Ⅳ), cortical comminution at the fracture end and partial weight-bearing time less than 4 weeks.

Objective:To compare the efficacy of femoral neck system (FNS) and cannulated compression screw (CCS) in the treatment of femoral neck fracture in the young and middle-aged patients.Methods:A retrospective cohort study was conducted to analyze the clinical data of 91 patients with femoral neck fracture admitted to Fuzhou Second Hospital from July 2020 to December 2021, including 52 males and 39 females; aged 23-65 years [(48.9±10.3)years]. Garden classification of the fracture found that 31 patients were with type I, 9 with type II, 12 with type III and 39 with type IV. Pauwels classification of the fracture found that 7 patients were with type I, 33 with type II and 51 with type III. A total of 53 patients were treated with FNS fixation (FNS group) and 38 patients with CCS fixation (CCS group). The operation time, intraoperative blood loss, Haidukewych fracture reduction quality, hospitalization time, Barthel index, fracture healing time, and weight-bearing time were compared between the two groups. The hip function was assessed by Harris hip score in both groups at postoperative 3 months, 6 months and 1 year and at the final follow-up. The incidences of postoperative complication and secondary surgery were also compared between the two groups.Results:All the patients were followed up for 15-31 months [(22.2±5.5)months]. There were no significant differences in the operation time, Haidukewych fracture reduction quality, hospitalization time, or Barthel index (all P>0.05). The intraoperative blood loss in the FNS group was 50.0(20.0,85.0)ml, which was more than that in the CCS group [20.0(10.0,50.0)ml] ( P<0.01). The fracture healing time, partial weight-bearing time, and full weight-bearing time in the FNS group [4.0(3.0,5.0)months, 3.0(2.0,3.0)months, 5.0(4.5,6.0)months] were shorter than those in the CCS group [6.0(5.0,7.0)months, 3.0(2.8,4.0)months, 6.0(6.0,7.0)months] (all P<0.01). The Harris hip score at postoperative 3 months, 6 months and 1 year and at the final follow-up were 74.0(71.0,77.0)points, 87.0(84.0,88.5)points, 91.0(88.0,95.0)points, and 94.0(91.0,96.0)points in the FNS group, significantly higher than those in the CCS group [73.0(70.0,74.0)points, 82.5(79.8,87.0)points, 88.0(83.5,91.0)points, 89.0(84.0,93.0)points] (all P<0.05 or 0.01). There were no statistically significant differences in the incidences of postoperative complication or secondary surgery between the two groups (all P>0.05). Conclusion:Compared with CCS, FNS can shorten fracture healing time, allow patients to carry full weight as soon as possible, and significantly improve hip function in the treatment of middle-aged and young adults with femoral neck fracture, although there is more intraoperative blood loss.

Objective:To investigate the clinical efficacy of the femoral neck system (FNS) after the reduction of the Schanz screw combined with the rod stick technique in the treatment of valgus-impacted femoral neck fracture.Methods:A retrospective analysis of clinical data from 66 patients with valgus-impacted femoral neck fractures from December 2019 to November 2021 has been performed. All patients were treated with the Femoral Neck System. Auxiliary reduction group (using the Schanz screw and rod stick technique), including 32 cases, 9 males and 23 females with an average age of 52.7±12.0 years (range, 28-77 years); 14 patients on the left side and 18 patients on the right side; body mass index 23.1±2.6 kg/m 2. Manual reduction group (using the traditional Flynn closed reduction technique), including 34 cases, 18 males and 16 females with an average age of 52.1±12.7 years (range, 26-75 years); 18 patients on the left side and 16 patients on the right side; body mass index 23.4±2.3 kg/m 2. The surgery time, intraoperative blood loss, complications, and Harris hip score at the last follow-up were collected and compared between the two groups. Preoperative and postoperative abduction angle and posterior tilt angle were measured in the anterior-posterior and lateral positions of the hip, as well as the length of the femoral neck shortening at the last follow-up. Pearson analysis was used to evaluate the correlation between preoperative and postoperative abduction angle and posterior tilt angle, the length of femoral neck shortening, and Harris hip score. Results:There were no significant differences in baseline data such as gender, age, side of injury, height, weight, and body mass index, and the surgery time and intraoperative blood loss between auxiliary reduction group and manual reduction group ( P>0.05). All 66 cases with a mean follow-up of 20.4 months (ranges 12-29 mouths). The fracture healing time was 5.0±0.9 weeks in the auxiliary reduction group and 4.9±0.8 weeks in the manual reduction group ( t=-0.41, P>0.05). There were no significant statistical difference in the preoperative abduction angle and preoperative posterior tilt angle between the auxiliary reduction group and the manual reduction group ( P>0.05). The postoperative abduction angle and posterior tilt angle of the auxiliary reduction group (1.8°±3.1°, 1.2°±3.0°) were significantly lower than those of the manual reduction group (13.7°±6.5°, 6.8°±4.1°, t=-9.55, P<0.001; t=-7.42, P<0.001). Preoperatively, 61 cases (92%) were associated with a posterior tilt of the femoral head, and 30 (46%) of them had a posterior tilt angle of more than 10°. The length of femoral neck shortening at the last follow-up and the moderate and severe femoral neck shortening rate postoperatively in the auxiliary reduction group (1.4±2.1 mm, 0, and 3%) were significantly lower than those in the manual reduction group (8.1±4.8 mm, 38%, and 32%, P<0.05). Harris hip score at the last follow-up in the auxiliary reduction group 91.1±4.5 was significantly higher than those in the manual reduction group 85.5±5.4 ( t=4.54, P<0.001). The postoperative abduction angle and length of femoral neck shortening showed correlations with the Harris hip score respectively ( r=-0.551, -0.743; P<0.001). In the auxiliary reduction group, 1 case of broken temporary fixed Kirschner wire was removed by nucleus pulposus forceps, and the fracture site healed after surgery. In 2 cases, the Schanz screw loosened and pulled out during the reduction process, and the successful reduction was achieved after increasing the depth of the Schanz screw insertion, and no peri-Schanz screw fracture occurred. After surgery, 3 cases (1 case in the auxiliary reduction group and 2 cases in the manual reduction group) developed avascular necrosis of the femoral head (18 months, 18 months, and 2 years after surgery, respectively), femoral head collapse and severe shortening of the femoral neck, all of which underwent total hip arthroplasty. Conclusion:FNS after the reduction of the Schanz screw combined with the rod stick technique in the treatment of valgus-impacted femoral neck fracture has the advantages of effectively correcting preoperative abduction angle and posterior tilt angle and reducing the length of femoral neck shortening, and it can obtain satisfactory short and medium-term clinical efficacy.

Objective:To investigate the risk factors for incision complications in open reduction and internal fixation of closed calcaneal fracture via an enlarged lateral L-shaped incision.Methods:A case-control study was used to analyze the clinical data of 128 patients (139 feet) with closed calcaneal fracture treated by open reduction and internal fixation via an enlarged lateral L-shaped incision in Fuzhou Second Hospital affiliated to Xiamen University from January 2019 to January 2022, including 113 males (123 feet) and 15 females (16 feet); aged 24-79 years [(48.2±10.8)years]. The fracture was on the one side in 117 patients and on both sides in 11 patients. According to Sanders classification, type I was noted in 3 feet, type II in 92, type III in 40, and type IV in 4. All patients were treated with an enlarged lateral L-shaped shaped incision for open reduction and internal fixation. The patients were divided into complication group (33 feet) and control group (106 feet), according to the occurrence of postoperative incisional complications. Data were recorded in both groups, including gender, age, side, fracture subtype, combined fractures, diabetes history, smoking history, local blistering, preoperative waiting time, bone graft, drainage, operative time, time of tourniquet use, number of prophylactic antibiotic use, postoperative treatment to improve microcirculation and preoperative and postoperative laboratory indices (white blood cell count, haemoglobin and albumin). The correlation between the above data and postoperative incisional complications was analyzed using the univariate analysis, followed by identification of independent risk factors by the multi-factor Logistic regression analysis.Results:Univariate analysis showed that diabetes history, smoking history, number of prophylactic antibiotic use, postoperative treatment to improve microcirculation, postoperative albumin and postoperative haemoglobin were associated with postoperative incisional complications (all P<0.05). On the contrary, gender, age, side, fracture subtype, combined fractures, local blistering, preoperative waiting time, bone graft, drainage, operative time, time of tourniquet use, preoperative white blood cell count, preoperative albumin, preoperative haemoglobin and postoperative white blood cell count were not associated with postoperative incisional complications (all P>0.05). Multi-factor Logistic regression analysis showed that diabetes history ( OR=3.51, 95% CI 1.29-9.50, P<0.05), smoking history ( OR=3.53, 95% CI 1.34-9.30, P<0.05), prophylactic antibiotic use<2 times ( OR=2.52, 95% CI 1.04-6.10, P<0.05) and lack of postoperative treatment to improve microcirculation ( OR=2.97, 95% CI 1.79-12.45, P<0.05) were significantly associated with postoperative incisional complications ( P<0.05). Conclusion:Diabetes history, smoking history, prophylactic antibiotic use<2 times and lack of postoperative treatment to improve microcirculation are independent risk factors for incisional complications in open reduction and internal fixation of closed calcaneal fracture via a lateral enlarged L-shaped shaped incision.

Objective: To investigate the effects of beta-blocker, propranolol and timolol on the proliferation and apoptosis of hemangioma stem cells (HemSCs). Methods: Different concentrations(3, 30, 90, 150 μmol/L)of propranolol and timolol were added in HemSCs culture respectively for 24, 48 and 72 h, and cell proliferation and apoptosis were detected by flow cytometry. Experimental data were analyzed using SPSS 19.0 software. Statistically significance was determined using Student′s t test. Values of P<0.05 were considered statistically significant. Results: Proliferation assay indicated that different concentrations of propranolol and timolol could inhibit HemSCs proliferation, and inhibition degree increased with increasing concentration. However, the effects of propranolol was slightly stronger than that of timolol at high concentrations (30, 90 and 150 μmol/L), but the opposite was observed at low concentration(3 μmol/L)(P<0.05). The results of apoptosis experiment showed that timolol had stronger effect than propranolol in promoting apoptosis at low concentrations (3 and 30 μmol/L), which was 13.7% and 1.1% higher, respectively. Conclusions Inhibiting HemSCs proliferation and promoting apoptosis may be one of the mechanisms of propranolol and timolol in treating infantile hemangioma.The specific effects of both varies with the concentration and time.

Objective To establish a reliable method of isolation and culture of infantile hemangioma stem cells (HemSCs).Methods Proliferating infantile hemangioma specimens were digested with collagenase to form a single cell suspension.The HemSCs were isolated with anti-CD133 MicroBeads,and were incubated in fibronectin coated 96-well plates with EBM-2 (10％ FBS).HemSCs were identified by morphological characteristics,flow cytometry,cell tubule formation assay,osteoinductive and adipogenic differentiation assay,and subcutaneous tumor formation assay.Results This method enables the rapid isolation of HemSCs which demonstrated typical mesenchymal stem cell morphology in culture.CD133 (+)HemSCs expressed CD29 (99.5％),CD44 (97.9％),CD90 (87.6％) and CD105 (98.5％),but barely expressed CD31 (0.2％),CD34 (0.1％),CD45 (0.1％) and CD144 (0.1％).These cells could differentiate into osteoblasts and adipocytes,and could form vascular wall like structure in vitro.When implanted into subcutaneous of the nude mice,the cells can develop into hemangioma like lesion histologically.Conclusions This technique can effectively isolate HemSCs from the proliferative hemangioma.These cells could be further used to reveal the charaeteristics of HemSCs,as well as for further study of widespread application.