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

OBJECTIVE: To investigate the accuracy and safety of pedicle screw placement using 3D-printed auxiliary guides in scoliosis correction surgery for adolescents. METHODS: A retrospective analysis was conducted on the clinical data of 51 patients who underwent posterior scoliosis correction surgery from January 2020 to March 2023. Among them, there were 35 cases of adolescent idiopathic scoliosis and 16 cases of congenital scoliosis. The patients were divided into two groups based on the auxiliary tool used:the 3D-printed auxiliary guide screw placement group (3D printing group) and the free-hand screw placement group (free-hand group, without auxiliary tools). The 3D printing group included 32 patients (12 males and 20 females) with an average age of (12.59±2.60) years;the free-hand group included 19 patients (7 males and 12 females) with an average age of (14.58±3.53) years. The two groups were compared in terms of screw placement accuracy and safety, spinal correction rate, intraoperative blood loss, number of intraoperative fluoroscopies, operation time, hospital stay, and preoperative and last follow-up scores of the Scoliosis Research Society-22 (SRS-22) questionnaire. RESULTS: A total of 707 pedicle screws were placed in the two groups, with 441 screws in the 3D printing group and 266 screws in the free-hand group. All patients in both groups successfully completed the surgery. There was a statistically significant difference in operation time between the two groups (P<0.05). The screw placement accuracy rate of the 3D printing group was 95.46% (421/441), among which the Grade A placement rate was 89.34% (394/441);the screw placement accuracy rate of the free-hand group was 86.47% (230/266), with a Grade A placement rate of 73.31% (195/266). There were statistically significant differences in the accuracy of Grade A, B, and C screw placements between the two groups (P<0.05), while no statistically significant differences were observed in intraoperative blood loss, number of fluoroscopies, correction rate, or hospital stay (P>0.05). In the SRS-22 questionnaire scores, the scores of functional status and activity ability, self-image, mental status, and pain of patients in each group at the last follow-up were significantly improved compared with those before surgery (P<0.05), but there were no statistically significant differences in all scores between the two groups (P>0.05). CONCLUSION In scoliosis correction surgery, compared with traditional free-hand screw placement, the use of 3D-printed auxiliary guides for screw placement significantly improves the accuracy and safety of screw placement and shortens the operation time.
Humans ; Male ; Scoliosis/surgery* ; Female ; Adolescent ; Printing, Three-Dimensional ; Retrospective Studies ; Pedicle Screws ; Child

PURPOSE: Hoffa fracture is a femoral condyle fracture in the coronal plane. The lateral condyle is more commonly involved. The diagnosis is often difficult to detect with routine radiographs. Conservative management in this type of fracture resulted in nonunion, malunion, and other complications, such as stiff knee. Therefore, surgical management is mandatory in displaced fractures. Previous studies suggest only application of cancellous screw fixation, but these are not enough to counter vertical shear stress. Therefore, this study will evaluate the clinical outcomes of open reduction and internal fixation of Letenneur type I Hoffa fracture using cancellous screws with posterior buttressing plate. METHOD: This was a prospective cohort study conducted from March 2017 to July 2022 in orthopaedics department of tertiary care center after approval of institutional ethical committee. The study included 36 patients with Letenneur type I fractures treated by open reduction and internal fixation using posterior buttress plate and cancellous screws. Radiographs and clinical outcomes, range of movement (ROM), bone union, and knee society score (KSS) of patients were assessed at the end of 4 and 12 months in the follow-ups. All statistical analysis was done using Epi info version 7.2.1.0. RESULTS: In the 36 patients with Letenneur type I fracture, the majority belong to younger age group between 25 and 54 years with 22 males and 14 females. The modes of injury were road traffic accidents in 25 patients and fall from height in 11 patients. The right knee was involved in 21 cases and left was involved in 15 cases. Lateral condyle involvement was seen in 27 cases and medial condyle in 9 cases. All 36 patients with Letenneur type I Hoffa fracture were evaluated 4 months after surgical intervention. The notable improvements were observed in terms of ROM 120.4° ± 5.0° and KSS 85.0 ± 4.2. At the 12-month follow-up, considerably better outcomes were maintained regarding ROM 128.1° ± 5.2° and KSS 89.3 ± 4.8 with p < 0.05 which was statistically significant. At the final follow-up, all patients had routine fracture healing with a union time of (3.2 ± 3.4) months. CONCLUSIONS Fixation of Letenneur type I Hoffa fracture with cancellous screws and posterior buttress plate is effective, reliable and capable of providing adequate stability. Buttress plate assisted fixation is a valuable enhancement of the conventional technique of lag screw fixation of Hoffa fractures.
Humans ; Bone Plates ; Male ; Female ; Fracture Fixation, Internal/instrumentation* ; Adult ; Prospective Studies ; Middle Aged ; Femoral Fractures/surgery* ; Bone Screws ; Range of Motion, Articular ; Young Adult ; Aged ; Hoffa Fracture

PURPOSE: Percutaneous ilio-sacral screw (ISS) insertion using conventional C-arm fluoroscopy has been a widely employed technique for pelvic posterior ring fixation, particularly in developing regions. However, this approach presents technical challenges, leading to a high malposition rate. We introduced a new method for ISS insertion without additional equipment or software and suggested whether it could reduce the malposition rate and operating time. METHODS: This is a retrospective cohort study. The study included all patients who underwent percutaneous ISS fixation between January 2020 and December 2022. Patients treated with open reduction or other types of implants were excluded. The patients were divided into 2 groups based on the screw insertion method: Group A utilized the traditional dual-plane adjustment method, while Group B received the newly introduced method. In all cases, conventional C-arm fluoroscopy was the sole guidance during the surgical procedure. Malposition rate, radiation exposure, and operating time were compared between groups. Post-operative CT scans were used to assess screw accuracy using the Smith grading method. The Student's t-test or the Mann-Whitney U test was chosen for comparing the quantitative variables based on the normality test results. The Chi-squared test was utilized for comparing qualitative variables. RESULTS: A total of 72 patients with pelvic posterior ring disruption treated with percutaneous ISS under conventional fluoroscopy guidance were included in this study. Among them, 32 patients were in Group A and 40 patients were in Group B. In Group B, the average operation duration per screw was 33 min with 29 fluoroscopy applications, which was significantly lower than that in Group A (44 min, p < 0.001, 38 times, p < 0.001, respectively). Furthermore, the post-operative CT scan revealed that only 10.7% (6/56) of screws in Group B were inappropriately positioned according to the Smith criteria. CONCLUSION The novel method introduced in this study demonstrated a reduction in both malposition rates and operating time compared to the traditional dual-plane adjustment method. Precise pre-operative CT planning in conjunction with conventional fluoroscopy could establish this method as a widely applicable technique for percutaneous ISS fixation.
Humans ; Fluoroscopy/methods* ; Retrospective Studies ; Bone Screws ; Female ; Male ; Tomography, X-Ray Computed/methods* ; Sacrum/diagnostic imaging* ; Middle Aged ; Operative Time ; Adult ; Fracture Fixation, Internal/methods* ; Ilium/diagnostic imaging* ; Aged

PURPOSE: Bone cement-reinforced fenestrated pedicle screws (FPSs) have been widely used in the internal fixation and repair of the spine with osteoporosis in recent years and show significant improvement in fixation strength and stability. However, compared with conventional reinforcement methods, the advantages of bone cement-reinforced FPSs remain undetermined. This article compares the effects of fenestrated and conventional pedicle screws (CPSs) combined with bone cement in the treatment of osteoporosis. METHODS: A clinical control study of FPSs and CPSs combined with bone cement reinforcement in osteoporotic vertebral internal fixation was performed using the database PubMed, Embase, Cochrane Library, CNKI, the Wanfang, and the China Biomedical Literature Service System. Two evaluators screened the relevant literature in strict accordance with the inclusion criteria (diagnosis of participants, type of clinical study, treatment with FPS and CPS, and outcome indicators) and exclusion criteria (duplicate literature and missing or incorrect data) and independently conducted data extraction and quality evaluation. Clinical control studies of direct comparison between FPS and CPS combined with bone cement reinforcement in patients who were definitively diagnosed with thoracolumbar fractures or spinal degenerative diseases were included. Quality evaluation was conducted using the Cochrane risk bias evaluation tool for randomized controlled studies and using the Newcastle-Ottawa scale for retrospective case-control studies. RevMan software (version 5.3) was used for the meta-analysis to compare the clinical efficacy, radiological results, and related complications of the 2 methods. RESULTS: A total of 13 articles were included, including 7 randomized controlled studies and 6 retrospective case-control studies. There were 909 patients in these studies, 451 in the FPS and polymethyl methacrylate (FPS & PMMA) group and 458 in the CPS and polymethyl methacrylate (CPS & PMMA) group. The results of the meta-analysis showed that there was no significant difference between the 2 groups in operation time, hospital stay, visual analogue score, Japanese orthopaedic association score, Oswestry disability index score, Cobb angle, vertebral body deformation index and fusion rate (p > 0.05). The mean difference of intraoperative bleeding volume was -10.45, (95% confidence intervals (CI) (-16.92, -3.98), p = 0.002), the mean difference of loss height of the anterior edge of the vertebral body after surgery was -0.69 (95% CI (-0.93, -0.44), p < 0.001), and the relative risk (RR) of overall complication rate was 0.43 (95% CI (0.27, 0.68), p < 0.001), including the RR of bone cement leakage rate was 0.57 (95% CI (0.39, 0.85), p = 0.005). The screw loosening rate (RR = 0.26, 95% CI (0.13, 0.54), p < 0.001) of the FPS group was significantly lower than that of the CPS group. CONCLUSION The existing clinical evidence shows that compared with the CPS combined with bone cement, the use of FPS repair in the internal fixation of an osteoporotic vertebral body can reduce the amount of intraoperative bleeding, be more conducive to maintaining the height of the vertebral body, and significantly reduce the incidence of postoperative complications such as bone cement leakage and screw loosening.
Humans ; Pedicle Screws ; Bone Cements ; Spinal Fractures/surgery* ; Osteoporotic Fractures/surgery* ; Fracture Fixation, Internal/instrumentation*

PURPOSE: The fixation method commonly employed worldwide for treating unstable fractures of the posterior pelvic ring is the percutaneous iliosacral screw technique. However, prolonged operation time and frequent fluoroscopies result in surgical risks. This study aimed to investigate whether a new triangulation method could reduce operative and fluoroscopy times and increase the accuracy of screw placement. METHODS: This study is a real-world retrospective cohort analysis that examined a patient cohort who underwent percutaneous iliosacral screw fixation between January 1, 2019 and December 31, 2022. Inclusion criteria were patients (1) diagnosed with posterior pelvic ring instability who underwent pelvic fracture closed reduction and percutaneous S1 transverse-penetrating iliosacral screw placement and (2) aged >18 years. Exclusion criteria were: (1) combined proximal femoral fractures, (2) severe soft tissue injury in the surgical area, (3) incomplete imaging data, and (4) declining to provide written informed consent by the patient. The patients were divided into 2 groups according to the screw insertion method: conventional and triangulation methods. Screw placement and fluoroscopy times recorded by the C-arm were compared between the 2 methods. The accuracy of screw placement was evaluated by Smith grading on postoperative CT. Normality tests were conducted to assess the distribution of the quantitative variables and the Chi-square test was used to compare the qualitative variables. RESULTS: The study included a total of 94 patients diagnosed with posterior pelvic ring instability, who underwent percutaneous iliosacral screw placement. The patients were divided into 2 groups: 46 patients treated with the conventional surgical method and 48 patients received the triangulation method. The operation time (61.13±9.69 vs. 35.77±6.27) min and fluoroscopy frequency times (52.15±9.29 vs. 24.40±4.04) of the triangulation method were significantly reduced (p<0.001). CONCLUSIONS The use of a triangular positioning technique for the surface positioning of percutaneous iliosacral screws could reduce the operative time and fluoroscopy frequency. And the screw placement accuracy using this new method was comparable to that using other conventional methods.
Humans ; Retrospective Studies ; Bone Screws ; Pelvic Bones/surgery* ; Male ; Female ; Fracture Fixation, Internal/methods* ; Fractures, Bone/surgery* ; Adult ; Middle Aged ; Fluoroscopy ; Aged ; Sacrum/surgery* ; Operative Time

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