OBJECTIVES: This study aims to analyze the biomechanics of three kinds of rigid internal fixation methods for condylar head fractures. METHODS: A three dimensional finite element model of the normal mandible was constructed. It was then used to prepare condylar head fracture finite element model and three kinds of rigid internal fixation finite element model (unilateral tension screw, bilateral tension screw, tension screw+titanium plate). The mechanical characteristics and changes of the mandible condyle under the same mechanical conditions were compared among the three different rigid internal fixation methods. RESULTS: The maximum equivalent stress and displacement of the non-free end of condyle under the rigid internal fixation method of unilateral tension screw were 71.03 MPa and 4.72 mm, respectively. The maximum equivalent stress and displacement of the free end of condyle were 78.45 MPa and 4.50 mm, respectively. The maximum stress of fracture suture was 3.27 MPa. The maximum equivalent stress and displacement of the non-free end of condyle under the rigid internal fixation method of bilateral tension screw were 70.52 MPa and 4.00 mm, respectively. The maximum equivalent stress and displacement of the free end of condyle were 72.49 MPa and 3.85 mm, respectively. The maximum stress of fracture suture was 2.33 MPa. The maximum equivalent stress and maximum displacement of the non-free end of condyle under the rigid internal fixation method of tension screw+titanium plate were 67.26 MPa and 2.66 mm, respectively. The maximum equivalent stress and maximum displacement of the free end of condyle were 69.66 MPa and 2.50 mm, respectively. The maximum stress of fracture suture was 2.18 MPa. CONCLUSIONS The tension screw+titanium plate rigid internal fixation method is the most conducive to biomechanical distribution for condylar head fractures.
Fracture Fixation, Internal/instrumentation* ; Mandibular Condyle/surgery* ; Biomechanical Phenomena ; Bone Screws ; Finite Element Analysis ; Humans ; Mandibular Fractures/surgery* ; Bone Plates ; Titanium ; Stress, Mechanical

This study explored a novel digital design and fabrication method for a double constrained split orthodontic miniscrew guide to improve the accuracy and safety of clinical miniscrew implantation and reduce related complications. A patient requiring miniscrew implantation was selected, and data were acquired using cone beam computed tomography (CBCT) and intraoral optical scanning. For the construction of a double constrained split guide including a screw-hole guide and an insertion rod guide, different types of software such as Mimics 24.0, Geomagic wrap 2021, and Materialise magics 21.0 were utilized for 3D reconstruction, model integration, and guide design. The guide was then fabricated via laser metal 3D printing. Model and intraoral try-in results demonstrated that the guide fitted well and was stable. Postoperative CBCT verified that the final miniscrew implantation site was consistent with the preoperative design, and no related complications occurred. This double constrained split orthodontic miniscrew guide provides a precise and safe digital solution for clinical miniscrew implantation.
Humans ; Bone Screws ; Cone-Beam Computed Tomography ; Printing, Three-Dimensional ; Orthodontic Anchorage Procedures/instrumentation* ; Imaging, Three-Dimensional ; Computer-Aided Design

This article aims to compare and analyze the biomechanical differences between wing-shaped titanium plates and traditional titanium plates in fixing acetabular anterior column and posterior hemi-transverse (ACPHT) fracture under multiple working conditions using the finite element method. Firstly, four sets of internal fixation models for acetabular ACPHT fractures were established, and the hip joint stress under standing, sitting, forward extension, and abduction conditions was calculated through analysis software. Then, the stress of screws and titanium plates, as well as the stress and displacement of the fracture end face, were analyzed. Research has found that when using wing-shaped titanium plates to fix acetabular ACPHT fractures, the peak stress of screws decreases under all working conditions, while the peak stress of wing-shaped titanium plates decreases under standing and sitting conditions and increases under forward and outward extension conditions. The relative displacement and mean stress of the fracture end face decrease under all working conditions, but the values are higher under forward and outward extension conditions. Wing-shaped titanium plates can reduce the probability of screw fatigue failure when fixing acetabular ACPHT fractures and can bear greater loads under forward and outward extension conditions, improving the mechanical stability of the pelvis. Moreover, the stress on the fracture end surface is more conducive to stimulating fracture healing and promoting bone tissue growth. However, premature forward and outward extension rehabilitation exercises should not be performed.
Titanium ; Bone Plates ; Humans ; Acetabulum/surgery* ; Fracture Fixation, Internal/methods* ; Biomechanical Phenomena ; Finite Element Analysis ; Bone Screws ; Fractures, Bone/surgery* ; Stress, Mechanical ; Working Conditions

OBJECTIVE: To explore effectiveness of TiRobot-assisted screw implantation in the treatment of coracoid process fractures of the scapula. METHODS: A retrospective analysis was conducted on the clinical data from 24 patients with coracoid process fractures of the scapula admitted between September 2019 and January 2024 and met selection criteria. Among them, 12 patients underwent TiRobot-assisted screw implantation (robot group) and 12 underwent manual screw implantation (control group) during internal fixation. There was no significant difference ( P>0.05) in baseline data such as gender, age, body mass index, disease duration, cause of injury, coracoid process fracture classification, and proportion of patients with associated injuries between the two groups. The incision length, operation time, intraoperative blood loss, hospital stay, accuracy of screw placement, coracoid process fracture healing time, and complications were recorded and compared, as well as pain visual analogue scale (VAS) score, and Constant-Murley score at last follow-up. RESULTS: The intraoperative blood loss and incision length in the robot group were significantly lower than those in the control group ( P<0.05); however, there was no significant difference in operation time and hospital stay between the two groups ( P>0.05). All patients were followed up 8-27 months (mean, 17.5 months), and the difference in follow-up time between the two groups was not significant ( P>0.05). At last follow-up, the VAS score for shoulder pain in the robot group was signifncatly lower compared to the control group, and the Constant-Murley score was significantly higher ( P<0.05). In the robot group, 16 screws were implanted intraoperatively, while 13 screws were implanted in the control group. Radiographic re-evaluation showed that the excellent and good rate of screw implantation was higher in the robot group (93.8%, 15/16) than in the control group (61.5%, 8/13), but the difference in the precision of screw implantation between the two groups was not significant ( P>0.05). Four patients in the robot group and 1 in the control group achieved double screws fixation; however, the difference in achieving double screws fixation between the two groups was not significant ( P>0.05). All fractures healed in both groups with 1 case of malunion in the control group. There was no significant difference in healing time between the two groups ( P>0.05). During follow-up, 1 patient in the control group experienced screw loosening and displacement. There was no significant difference in the incidence of screw loosening and fracture malunion between the two groups ( P>0.05). CONCLUSION Compared with manual screw implantation, TiRobot-assisted minimally invasive treatment of coracoid process fractures of the scapula can reduce intraoperative blood loss, shorten incision length, alleviate pain, and obtain better promote shoulder joint functional recovery.
Humans ; Male ; Female ; Retrospective Studies ; Fracture Fixation, Internal/instrumentation* ; Minimally Invasive Surgical Procedures/instrumentation* ; Adult ; Middle Aged ; Fractures, Bone/surgery* ; Bone Screws ; Coracoid Process/surgery* ; Robotic Surgical Procedures/methods* ; Scapula/surgery* ; Treatment Outcome ; Operative Time ; Young Adult ; Length of Stay ; Blood Loss, Surgical

OBJECTIVE: To compare the short-term effectiveness between Gamma 3 intramedullary nails and Gamma 3 U-Blade system in the treatment of osteoporotic intertrochanteric fractures in the elderly. METHODS: A retrospective analysis was conducted on the clinical data of 124 elderly patients with osteoporotic intertrochanteric fractures, who were admitted between February 2020 and February 2023 and met the selection criteria. The fractures were fixed with Gamma 3 intramedullary nails in 65 patients (control group) and Gamma 3 U-Blade systems in 59 patients (UB group). The differences between the two groups were not significant in age, gender, body mass index, American Society of Anesthesiologists (ASA) classification, bone mineral density, time from injury to operation, fracture classification, and affected side ( P>0.05). The operation time, intraoperative blood loss, hospital stay, and fracture healing time were recorded; the tip-apex distance, fracture reduction quality, and lag screw position were evaluated on X-ray films at immediate after operation; the lag screw sliding distance and change value of neck-shaft angle were measured on X-ray films at last follow-up. Harris hip score at 1 year after operation and the occurrence of internal fixation-related complications were compared between the two groups. RESULTS: The operation time, intraoperative blood loss, and hospital stay in the UB group increased compared to the control group, but the differences were not significant ( P>0.05). All patients in both groups were followed up 12-24 months (mean, 17.1 months). At 12 months after operation, there was no significant difference in the Harris hip score between the two groups ( P<0.05). Radiological examination showed that there was no significant difference between the two groups ( P>0.05) in terms of tip-apex distance, fracture reduction quality, and lag screw position. Fractures healed in both groups, and there was no significant difference in healing time ( P>0.05). At last follow-up, the change value of neck-shaft angle and lag screw sliding distance in the UB group were significantly lower than those in the control group ( P<0.05). During follow-up, no related complications occurred in the UB group, while 6 cases (9.2%) in the control group experienced complications, and the difference in the incidence was significant ( P<0.05). CONCLUSION For the osteoporotic intertrochanteric fractures in the elderly, the Gamma 3 U-Blade system fixation can achieve good short-term effectiveness, with better imaging results compared to Gamma 3 intramedullary nails fixation.
Humans ; Retrospective Studies ; Hip Fractures/surgery* ; Male ; Female ; Aged ; Fracture Fixation, Intramedullary/methods* ; Osteoporotic Fractures/surgery* ; Bone Nails ; Bone Screws ; Aged, 80 and over ; Treatment Outcome ; Fracture Healing ; Operative Time ; Length of Stay

OBJECTIVE: To analyze the effectiveness of three internal fixation methods, namely hollow screw combined with Kirschner wire tension band, hollow screw combined with anchor nail, and modified 1/3 tubular steel plate, in the treatment of avulsion fracture of tibial tubercle (AFTT) in adolescents. METHODS: Between January 2018 and September 2023, 19 adolescent AFTT patients who met the selection criteria were admitted. According to different internal fixation methods, patients were divided into group A (8 cases, hollow screw combined with Kirschner wire tension band), group B (6 cases, hollow screw combined with anchor nail), and group C (5 cases, modified 1/3 tubular steel plate). There was no significant difference in the baseline data of age, gender, side, cause of injury, Ogden classification, and time from injury to operation among the three groups ( P>0.05). The range of motion (ROM), weight-bearing time, normal activity time of knee joint, and the hospital for special surgery (HSS) score at last follow-up were recorded and compared among the three groups. Recorded whether the fracture was displaced, whether the fracture line was blurred at 1 month after operation, whether there was epiphyseal dysplasia, and whether there was incision infection and other complications. RESULTS: There was no significant difference in hospital stay between the groups ( P>0.05). All patients were followed up 10-24 months, with an average of 14.3 months; there was no significant difference between the groups ( P>0.05). All the incisions healed well without soft tissue irritation or fracture nonunion, and no limb shortening deformity or epiphyseal dysplasia was found during follow-up. At 1 month after operation, the knee joint ROM and hospitalization expenses in group A were better than those in groups B and C, the fracture healing time, knee joint weight-bearing time, and normal activity time of knee joint were better than those in group C, and the hospitalization expenses in group C were better than those in group B, with significant differences ( P<0.05); there was no significant difference in the other indicators between the groups ( P>0.05). In group A, the fracture line was blurred 1 month postoperatively, the fracture ends were in close contact, and there was no fracture displacement; in groups B and C, the fracture line was clear in 2 cases, and 1 case in group C had slight fracture displacement; except for 1 case in group B, there was no fracture split in the other two groups. There was no significant difference in the incidences of blur of fracture line, fracture displacement, and intraoperative bone split between the groups at 1 month after operation ( P>0.05). At last follow-up, the HSS scores of knee joints in the three groups were excellent and good, and there was no significant difference between the groups ( P>0.05). CONCLUSION Hollow screw combined with Kirschner wire tension band technique is effective in treating adolescent AFTT, which has the advantages of stabilizing fracture, accelerating fracture healing and rehabilitation, early feasible knee joint functional exercise, and reducing hospitalization expenses.
Humans ; Tibial Fractures/surgery* ; Adolescent ; Male ; Fracture Fixation, Internal/instrumentation* ; Female ; Fractures, Avulsion/surgery* ; Bone Wires ; Bone Screws ; Bone Plates ; Treatment Outcome ; Range of Motion, Articular ; Bone Nails ; Weight-Bearing ; Fracture Healing

OBJECTIVE: To investigate the effectiveness of using 3 hollow compression screws combined with 1 screw off-axis fixation under the guidance of three-dimensional (3D) printed guide plate with mortise-tenon joint structure (mortise-tenon joint plate) for the treatment of Pauwels type Ⅲ femoral neck fractures. METHODS: A clinical data of 78 patients with Pauwels type Ⅲ femoral neck fractures, who were admitted between August 2022 and August 2023 and met the selection criteria, was retrospectively analyzed. The operations were assisted with mortise-tenon joint plates in 26 cases (mortise-tenon joint plate group) and traditional guide plates in 28 cases (traditional plate group), and without guide plates in 24 cases (control group). There was no significant difference in the baseline data of gender, age, body mass index, cause of injury, and fracture side between groups ( P>0.05). The operation time, intraoperative blood loss, frequency of intraoperative fluoroscopy, incision length, incidence of postoperative deep vein thrombosis of lower extremity, pain visual analogue scale (VAS) score at 1 week after operation, and Harris score of hip joint at 3 months after operation were recorded and compared. X-ray re-examination was taken to check the quality of fracture reduction, fracture healing, and the shortening length of the femoral neck at 3 months after operation, and the incidences of internal fixation failure and osteonecrosis of the femoral head during operation. RESULTS: Compared with the control group, the operation time, intraoperative blood loss, and frequency of intraoperative fluoroscopy reduced in the two plate groups, and the quality of fracture reduction was better, but the incision was longer, and the differences were significant ( P<0.05). The operation time and intraoperative blood loss were significantly higher in the traditional plate group than in the mortise-tenon joint plate group ( P<0.05), the incision was significantly longer ( P<0.05); and the difference in fracture reduction quality and the frequency of intraoperative fluoroscopy was not significant between two plate groups ( P>0.05). There was 1 case of deep vein thrombosis of lower extremity in the traditional plate group and 1 case in the control group, while there was no thrombosis in the mortise-tenon joint plate group. There was no significant difference in the incidence between groups ( P>0.05). All patients were followed up 12-15 months (mean, 13 months). There was no significant difference in VAS score at 1 week and Harris score at 3 months between groups ( P>0.05). Compared with the control group, the fracture healing time and the length of femoral neck shortening at 3 months after operation were significantly shorter in the two plate groups ( P<0.05). There was no significant difference between the two plate groups ( P>0.05). There was no significant difference in the incidences of non-union fractures, osteonecrosis of the femoral head, or internal fixation failure between groups ( P>0.05). CONCLUSION For Pauwels type Ⅲ femoral neck fractures, the use of 3D printed guide plate assisted reduction and fixation can shorten the fracture healing time, reduce the incidence of postoperative complications, and be more conducive to the early functional exercise of the affected limb. Compared with the traditional guide plate, the mortise-tenon joint plate can reduce the intraoperative bleeding and shorten the operation time.
Humans ; Femoral Neck Fractures/diagnostic imaging* ; Bone Plates ; Fracture Fixation, Internal/instrumentation* ; Male ; Female ; Retrospective Studies ; Middle Aged ; Bone Screws ; Adult ; Aged ; Treatment Outcome ; Printing, Three-Dimensional ; Operative Time

OBJECTIVE: To investigate the effectiveness of 5G remote robotic surgery in the treatment of pelvic fractures. METHODS: A retrospective analysis was conducted on the clinical data of 160 patients with pelvic fractures admitted between July 2023 and June 2024 who met the selection criteria. Among these patients, 80 underwent internal fixation surgery with the assistance of 5G remote robotic surgery (5G group), while 80 received local robotic surgical assistance (control group). Baseline characteristics, including gender, age, body mass index, disease duration, cause of injury, and fracture classification, were compared between the two groups, and no significant difference was found ( P>0.05). The incision length, operation time, intraoperative blood loss, hospital stay, accuracy of screw placement, maximum residual displacement postoperatively, quality of fracture reduction, incidence of complications, Majeed pelvic function score and classification at last follow-up were recorded and compared between the two groups. RESULTS: In the 5G group, 180 screws were implanted during surgery, while 213 screws were implanted in the control group. The 5G group demonstrated significantly reduced intraoperative blood loss and shorter incision length compared to the control group ( P<0.05). No significant difference was observed between the two groups in terms of operation time or hospital stay ( P>0.05). Radiographic evaluation revealed excellent and good reduction rates of 98.8% (79/80) in the 5G group and 97.5% (78/80) in the control group, while excellent and good screw placement accuracy rates were 98.3% (177/180) in the 5G group and 95.8% (204/213) in the control group. No significant difference was found between the two groups in maximum residual displacement, reduction quality, or screw placement accuracy ( P>0.05). All patients were followed up 7-16 months (mean, 11.3 months), with no significant difference in follow-up duration between the groups ( P>0.05). No perioperative or follow-up complication, such as wound infection, iatrogenic fractures, iatrogenic neurovascular injury, screw loosening or breakage, or nonunion, were observed in either group. The control group exhibited a worse degree of gait alteration compared to the 5G group ( P<0.05), while no significant difference was found in incidences of squatting limitation or persistent pain ( P>0.05). At last follow-up, no significant difference was observed between the groups in Majeed pelvic function scores or grading ( P>0.05). CONCLUSION Compared with the local surgery group, 5G remote robotic surgery supported by remote expert technical guidance demonstrated smaller incision lengths, less intraoperative blood loss, and fewer postoperative complications, and was shown to be a precise, minimally invasive, safe, and reliable surgical method.
Humans ; Robotic Surgical Procedures/instrumentation* ; Pelvic Bones/surgery* ; Male ; Retrospective Studies ; Fracture Fixation, Internal/instrumentation* ; Female ; Fractures, Bone/surgery* ; Middle Aged ; Bone Screws ; Adult ; Operative Time ; Treatment Outcome ; Blood Loss, Surgical ; Length of Stay ; Postoperative Complications/epidemiology* ; Aged ; Young Adult

OBJECTIVE: To explore effectiveness of intermediate screw assisted reduction and fixation technique in the treatment of Schatzker type Ⅴ and Ⅵ tibial plateau fractures. METHODS: A clinical data of 22 patients with Schatzker type Ⅴ and Ⅵ tibial plateau fractures, who were admitted between June 2022 and December 2023 and met the selection criteria, was retrospectively analyzed. During operation, the intermediate screw assisted reduction and fixation technique was used. There were 14 males and 8 females with an average age of 46.3 years (range, 17-65 years). The fractures were caused by traffic accident in 13 cases, by falls in 5 cases, and by falling from height in 4 cases. According to Schatzker classification criteria, 9 cases were type Ⅴ and 13 cases were type Ⅵ. The interval between injury and operation was 5-12 days (mean, 7.9 days). The operation time, intraoperative fluoroscopy times, and length of hospital stay were recorded. The range of motion of knee joint and Hospital for Special Surgery (HSS) score were recorded at last follow-up. X-ray films were taken to review the fracture healing. Rasmussen score, tibial plateau varus angle (TPVA), and posterior tibial slope (PTS) were estimated before operation, at immediate after operation, and at last follow-up in order to evaluate the fracture reduction effect and postoperative outcome. RESULTS: The operation time was 85-140 minutes (mean, 103.9 minutes). Intraoperative fluoroscopy was performed 7-15 times (mean, 10.1 times). All incisions healed by first intention after operation, and no complication such as nerve or blood vessel injury occurred. The length of hospital stay ranged from 8 to 17 days (mean, 12.4 days). All patients were followed up 10-22 months (mean, 14.8 months). At last follow-up, the range of motion of knee joint was 110°-140° (mean, 125°). HSS score was rated as excellent in 16 cases, good in 5 cases, and fair in 1 case, with an excellent and good rate of 95.5%. X-ray films reexamination showed that all fractures healed with the healing time of 12-17 weeks (mean, 14.8 weeks). No internal fixation failure occurred. Rasmussen score, TPVA, and PTS at immediate after operation and at last follow-up were significantly superior to those before operation ( P<0.05). And there was no significant difference between immediately after operation and last follow-up ( P>0.05). CONCLUSION The treatment of Schatzker type Ⅴ and Ⅵ tibial plateau fractures with intermediate screw assisted reduction and fixation technique is reliable, which can reduce the difficulty of reduction and fixation, improve the efficiency of reduction and fixation, reduce the operation time, achieve satisfactory reduction and fixation effect and postoperative prognosis, and achieve good recovery of knee joint function.
Humans ; Tibial Fractures/diagnostic imaging* ; Male ; Female ; Adult ; Middle Aged ; Bone Screws ; Fracture Fixation, Internal/instrumentation* ; Retrospective Studies ; Adolescent ; Aged ; Young Adult ; Treatment Outcome ; Range of Motion, Articular ; Operative Time ; Length of Stay ; Tibial Plateau Fractures

OBJECTIVE: To investigate whether adding 1 transverse screw (TS) to the triangular parallel cannulated screw (TPCS) fixation has a mechanical stability advantage for Pauwels type Ⅲ femoral neck fractures by conducting finite element analysis on four internal fixation methods. METHODS: Based on CT data of a healthy adult male volunteer's femur, three Pauwels type Ⅲ femoral neck fracture models (Pauwels angle 70°, Pauwels angle 80°, and Pauwels angle 70° combined with bone defect) were constructed using Mimics 21.0 software and SolidWorks 2017 software. Four different internal fixation models were built at the same time, including TPCS, TPCS+TS, three cross screws (TCS), and TPCS+medial buttress plate (MBP). The mechanical stability of different models under the same load was compared by finite element analysis. RESULTS: The femoral model established in this study exhibited a maximum stress of 28.62 MPa, with relatively higher stress concentrated in the femoral neck. These findings were comparable to previous studies, indicating that the constructed femoral finite element model was correct. The maximum stress of internal fixation in finite element analysis showed that TCS was the lowest and TPCS+MBP was the highest in Pauwels angle 70° and 80° models, while TPCS+TS was the lowest and TCS was the highest in Pauwels angle 70° combined with bone defect model. The maximum displacement of internal fixation in each fracture model was located at the top of the femoral head, with TCS having the highest maximum displacement of the femur. The maximum stress of fracture surface in finite element analysis showed that TCS was the lowest and TPCS was the highest in the Pauwels angle 70° model, while TPCS+MBP was the lowest and TPCS/TCS were the highest in the Pauwels angle 80° model and the Pauwels angle 70° combined with bone defect model, respectively. The maximum displacement of fracture surfece analysis showed that TPCS+MBP was the lowest and TCS was the highest in Pauwels angle 70° and 80° models, while TPCS+TS was the lowest and TCS was the highest in Pauwels angle 70° combined with bone defect model. CONCLUSION For Pauwels type Ⅲ femoral neck fractures, the biomechanical stability of TPCS+TS was superior to that of TPCS alone and TCS, but it has not yet reached the level of TPCS+MBP.
Finite Element Analysis ; Humans ; Femoral Neck Fractures/diagnostic imaging* ; Bone Screws ; Fracture Fixation, Internal/instrumentation* ; Male ; Bone Plates ; Stress, Mechanical ; Biomechanical Phenomena ; Tomography, X-Ray Computed ; Adult ; Femur Neck/surgery*