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 evaluate the impacts of 2 reduction sequences on the surgical treatment of Schatzker type Ⅳ tibial plateau fractures with coronal plane subluxation.Methods:A retrospective analysis was conducted of the 53 patients who had been treated for Schatzker type Ⅳ tibial plateau fractures with coronal plane subluxation at Department of Orthopaedics, Fuzhou Second General Hospital from June 2020 to October 2023. The patients were divided into 2 groups according to the 2 reduction sequences employed during surgery. In the observation group of 25 patients [16 males and 9 females with an age of (47.2±10.2) years], the coronal plane subluxation was first reduced and temporarily fixed, followed by reduction of the medial plateau, and fixation of both the medial and lateral plateaus. In the control group of 28 patients [13 males and 15 females with an age of (50.6±15.4) years], in the traditional manner, the medial plateau was first reduced and temporarily fixed, followed by reduction of the coronal plane subluxation and finally by fixation of both plateaus. Outcomes compared between the 2 groups included surgical duration, intraoperative blood loss, and fracture healing time. Additionally, postoperative outcomes were assessed on the second day after surgery using such parameters as medial proximal tibial angle, lateral plateau widening, rate of coronal plane subluxation, and Rasmussen score. Knee joint function was evaluated at the final follow-up.Results:No significant differences were found between the 2 groups in baseline characteristics, ensuring comparability ( P>0.05). The mean follow-up duration for all patients was (12.6±4.2) months. There were no significant differences in surgical duration, intraoperative blood loss, fracture healing time or medial proximal tibial angle between the 2 groups ( P>0.05). The observation group demonstrated a significantly higher success rate by Rasmussen score (100.0% [25/25]) than the control group (78.6% [22/28]), significantly smaller postoperative lateral plateau widening [(3.70±2.42) mm] than the control group [(5.79±3.38) mm], a significant lower rate of coronal plane subluxation [16.0% (4/25)] than the control group [42.9% (12/28)], a significantly higher Hospital for Special Surgery (HSS) knee score [(83.8±5.4) points] than the control group [(80.0±6.5) points] (all P<0.05). Conclusion:Compared to the traditional reduction sequence, the modified reduction sequence prioritizing the reduction of coronal plane subluxation during surgery for Schatzker type Ⅳ tibial plateau fractures with coronal plane subluxation leads to superior short-term outcomes, effectively reduced widening of postoperative lateral tibial plateau and a decreased rate of coronal plane subluxation.

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.

Postoperative infection of internal fixation of closed fractures the lower limbs in adults represents a devastating complication, characterized by diagnostic challenges, prolonged treatment duration and high disability rates. Current management of these infections faces multiple challenges, such as difficulties in early accurate diagnosis, and various controversies about the treatment plan, leading to poor overall diagnosis and treatment results. To address these issues, based on evidence-based medicine and principles with emphasis on scientific rigor, clinical applicability and innovation, the Trauma Branch of the Chinese Medical Association, Orthopedic Branch of the Chinese Medical Doctor Association, Orthopedics Branch of the Chinese Medical Association, and Trauma Orthopedics and Polytrauma Group of the Resuscitation and Emergency Committee of the Chinese Medical Doctor Association have collaboratively organized a panel of relevant experts to develop the Guideline for diagnosis and treatment of infection after internal fixation of closed lower limb fractures in adults ( version 2025). The guideline proposed 10 recommendations, aiming to provide a foundation for standardized diagnosis and treatment of postoperative infection in adults with closed lower limb fractures.

Postoperative infection of internal fixation of closed fractures the lower limbs in adults represents a devastating complication, characterized by diagnostic challenges, prolonged treatment duration and high disability rates. Current management of these infections faces multiple challenges, such as difficulties in early accurate diagnosis, and various controversies about the treatment plan, leading to poor overall diagnosis and treatment results. To address these issues, based on evidence-based medicine and principles with emphasis on scientific rigor, clinical applicability and innovation, the Trauma Branch of the Chinese Medical Association, Orthopedic Branch of the Chinese Medical Doctor Association, Orthopedics Branch of the Chinese Medical Association, and Trauma Orthopedics and Polytrauma Group of the Resuscitation and Emergency Committee of the Chinese Medical Doctor Association have collaboratively organized a panel of relevant experts to develop the Guideline for diagnosis and treatment of infection after internal fixation of closed lower limb fractures in adults ( version 2025). The guideline proposed 10 recommendations, aiming to provide a foundation for standardized diagnosis and treatment of postoperative infection in adults with closed lower limb fractures.

Objective:To evaluate the impacts of 2 reduction sequences on the surgical treatment of Schatzker type Ⅳ tibial plateau fractures with coronal plane subluxation.Methods:A retrospective analysis was conducted of the 53 patients who had been treated for Schatzker type Ⅳ tibial plateau fractures with coronal plane subluxation at Department of Orthopaedics, Fuzhou Second General Hospital from June 2020 to October 2023. The patients were divided into 2 groups according to the 2 reduction sequences employed during surgery. In the observation group of 25 patients [16 males and 9 females with an age of (47.2±10.2) years], the coronal plane subluxation was first reduced and temporarily fixed, followed by reduction of the medial plateau, and fixation of both the medial and lateral plateaus. In the control group of 28 patients [13 males and 15 females with an age of (50.6±15.4) years], in the traditional manner, the medial plateau was first reduced and temporarily fixed, followed by reduction of the coronal plane subluxation and finally by fixation of both plateaus. Outcomes compared between the 2 groups included surgical duration, intraoperative blood loss, and fracture healing time. Additionally, postoperative outcomes were assessed on the second day after surgery using such parameters as medial proximal tibial angle, lateral plateau widening, rate of coronal plane subluxation, and Rasmussen score. Knee joint function was evaluated at the final follow-up.Results:No significant differences were found between the 2 groups in baseline characteristics, ensuring comparability ( P>0.05). The mean follow-up duration for all patients was (12.6±4.2) months. There were no significant differences in surgical duration, intraoperative blood loss, fracture healing time or medial proximal tibial angle between the 2 groups ( P>0.05). The observation group demonstrated a significantly higher success rate by Rasmussen score (100.0% [25/25]) than the control group (78.6% [22/28]), significantly smaller postoperative lateral plateau widening [(3.70±2.42) mm] than the control group [(5.79±3.38) mm], a significant lower rate of coronal plane subluxation [16.0% (4/25)] than the control group [42.9% (12/28)], a significantly higher Hospital for Special Surgery (HSS) knee score [(83.8±5.4) points] than the control group [(80.0±6.5) points] (all P<0.05). Conclusion:Compared to the traditional reduction sequence, the modified reduction sequence prioritizing the reduction of coronal plane subluxation during surgery for Schatzker type Ⅳ tibial plateau fractures with coronal plane subluxation leads to superior short-term outcomes, effectively reduced widening of postoperative lateral tibial plateau and a decreased rate of coronal plane subluxation.

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 properties of posterolateral distal humeral plate, inverted anterior proximal humerus internal locking system (PHILOS), and anterior reconstruction plate in the treatment of distal humeral shaft fractures by a finite element analysis.Methods:One healthy adult male volunteer, aged 27 years, with a height of 171 cm and a weight of 70 kg, was recruited for this study. The finite element method was used to establish a simulation model of distal humeral shaft fracture. The maximum displacement and maximum stress were compared between fixation with posterolateral distal humeral plate (group A), fixation with inverted anterior PHILOS (group B), and fixation with anterior reconstruction plate (group C).Results:In groups A, B, and C, respectively, the overall stress peak values were 409.07 MPa, 217.04 MPa, and 370.64 MPa; the peak stresses under torsional load were 234.55 MPa, 348.80 MPa and 458.17 MPa; the overall stress peaks under bending load were 250.22 MPa, 466.76 MPa, and 582.32 MPa. The smaller the stress, the smaller the risk of fatigue fracture. In groups A, B, and C, respectively, the overall displacement peak values were 5.18 mm, 3.04 mm and 3.75 mm; the peak displacements under torsional load were 1.20 mm, 1.02 mm and 2.05 mm; the peak displacements under bending load were 3.85 mm, 5.28 mm and 9.04 mm. The smaller the displacement, the better the fixation stability.Conclusions:In the treatment of distal humeral shaft fractures, fixation with inverted anterior PHILOS leads to the best mechanical stability under axial compression and torsional stress, while fixation with the posterolateral distal humeral plate leads to the best mechanical stability under bending stress.

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.